Skip to main content
Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease logoLink to Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease
. 2019 Jan 12;8(2):e010839. doi: 10.1161/JAHA.118.010839

Radial Artery Versus Right Internal Thoracic Artery Versus Saphenous Vein as the Second Conduit for Coronary Artery Bypass Surgery: A Network Meta‐Analysis of Clinical Outcomes

Mario Gaudino 1,†,, Roberto Lorusso 2,, Mohamed Rahouma 1, Ahmed Abouarab 1, Derrick Y Tam 3, Cristiano Spadaccio 4,5, Gaëlle Saint‐Hilary 6, Jeremy Leonard 1, Mario Iannaccone 7, Fabrizio D'Ascenzo 7, Antonino Di Franco 1, Giovanni Soletti 1, Mohamed K Kamel 1, Christopher Lau 1, Leonard N Girardi 1, Thomas A Schwann 8, Umberto Benedetto 9, David P Taggart 10, Stephen E Fremes 3
PMCID: PMC6497341  PMID: 30636525

Abstract

Background

There remains uncertainty regarding the second‐best conduit after the internal thoracic artery in coronary artery bypass grafting. Few studies directly compared the clinical results of the radial artery (RA), right internal thoracic artery (RITA), and saphenous vein (SV). No network meta‐analysis has compared these 3 strategies.

Methods and Results

MEDLINE and EMBASE were searched for adjusted observational studies and randomized controlled trials comparing the RA, SV, and/or RITA as the second conduit for coronary artery bypass grafting. The primary end point was all‐cause long‐term mortality. Secondary end points were operative mortality, perioperative stroke, perioperative myocardial infarction, and deep sternal wound infection (DSWI). Pairwise and network meta‐analyses were performed. A total of 149 902 patients (4 randomized, 31 observational studies) were included (RA, 16 201, SV, 112 018, RITA, 21 683). At NMA, the use of SV was associated with higher long‐term mortality compared with the RA (incidence rate ratio, 1.23; 95% CI, 1.12–1.34) and RITA (incidence rate ratio, 1.26; 95% CI, 1.17–1.35). The risk of DSWI for SV was similar to RA but lower than RITA (odds ratio, 0.71; 95% CI, 0.55–0.91). There were no differences for any outcome between RITA and RA, although DSWI trended higher with RITA (odds ratio, 1.39; 95% CI, 0.92–2.1). The risk of DSWI in bilateral internal thoracic artery studies was higher when the skeletonization technique was not used.

Conclusions

The use of the RA or the RITA is associated with a similar and statistically significant long‐term clinical benefit compared with the SV. There are no differences in operative risk or complications between the 2 arterial conduits, but DSWI remains a concern with bilateral ITA when skeletonization is not used.

Keywords: arterial conduits, coronary artery bypass, coronary artery bypass graft surgery, saphenous vein graft

Subject Categories: Cardiovascular Surgery, Revascularization


Clinical Perspective

What Is New?

  • The use of the radial artery or the right internal thoracic artery is associated with a similar and statistically significant long‐term clinical benefit compared with the saphenous vein.

  • There are no differences in operative risk or complications between the two arterial conduits, but deep sternal wound infection remains a concern with bilateral internal thoracic artery when skeletonization is not used.

What Are the Clinical Implications?

  • The results of our study support the superiority of the use of a second arterial over venous graft, and suggest the equivalence in long‐term and perioperative outcomes among RITA and radial artery.

Introduction

One of the most important unresolved questions in contemporary coronary artery bypass (CABG) surgery is the choice of the conduit to complement the internal thoracic to left anterior descending artery anastomosis.

The radial artery (RA), the right internal thoracic artery (RITA), and the saphenous vein (SV) are all currently being used routinely, although the majority of the surgeons favor the SV.

Abundant observational evidence suggests a survival benefit for the use of arterial grafts, and the current guidelines encourage a wider use of the RA or the RITA, especially in patients with a long life expectancy.1, 2, 3, 4 However, the reported benefit of arterial grafts has not been confirmed in a large randomized controlled trial (RCT) , and it has been hypothesized that the survival benefit seen in observational studies may be due to unmatched confounders and treatment allocation bias.5, 6 An important additional unresolved question is the relative role of the RITA and RA. Although the RITA is biologically identical to the left internal thoracic artery, data comparing the patency rate and clinical outcome of the 2 arterial grafts has been contradictory and inconclusive.7, 8

Network meta‐analysis (NMA) with adjusted indirect comparison among treatments is a useful technique to reduce the potential for heterogeneity or allocation biases, in particular when analyzing both RCTs and observational studies.9

To date, the only published NMA comparing the SV, RITA and RA as the second conduit in CABG focused only on angiographic patency and not on clinical outcomes.10 Due to the well‐known discrepancy between occlusion of grafts to non–left anterior descending arteries and clinical outcomes,11 a similar analysis focusing on clinical end points is of particular relevance to the surgical community.

Here, we performed an NMA with the aim to specifically investigate the differences in late survival (primary outcome) and other clinical outcomes according to the type of second graft used for CABG.

Material and Methods

The authors declare that all supporting data are available within the article and its online supplementary files. This systematic review and NMA follows the Preferred Reporting Items for Systematic Reviews and Meta‐Analysis statement.12

Data Sources and Systematic Literature Review

Ovid's version of MEDLINE and EMBASE were searched from inception to February 2018 (full search strategy attached in Table S1). Inclusion criteria were English language publications, adjusted or matched observational studies or RCTs comparing RA and/or SV and/or RITA as the second conduit for CABG. In addition, we searched recent meta‐analyses and reviews on this topic for potential additional studies. All citations were reviewed by 3 investigators independently (A.A., A.D.F., and M.R.), and any disagreements were resolved by consensus. In case of overlapping studies, the largest series were included.

Data Extraction and Quality Assessment

Data extraction was performed independently by 2 investigators (A.A. and A.D.F.). The following variables were included: study demographics (sample size, number of centers, institutions involved, publication year, study period, design and country, length of follow‐up), patient demographics (age, sex, diabetes mellitus, and ejection fraction) and procedural (use of skeletonization) and postoperative data. The quality of the included studies was assessed by the Newcastle–Ottawa Scale (Table S2).13 Only RCTs and observational studies of high quality (Newcastle–Ottawa Scale score >6) were included in the final analysis.

Outcomes

The primary outcome was all‐cause long‐term mortality. The secondary outcomes were operative mortality, perioperative stroke, perioperative myocardial infarction (MI), and deep sternal wound infection (DSWI), as defined in the original articles.

Two levels of analyses were conducted for all outcomes: (1) pairwise meta‐analysis between arterial grafts (with either RITA or RA) and SV and between RITA and RA, and (2) network meta‐analyses between RITA, RA, and SV.

Data Synthesis and Analysis

Pairwise meta‐analysis

Late outcomes were pooled as the natural logarithm of the incident rate ratio (IRR) to account for potentially different follow‐up durations between the groups. We estimated the IRR through several means depending on the available study data. When hazard ratios for matched (preferentially)/adjusted cohorts were provided, we took the natural logarithm of the hazard ratio; the standard error was derived from the 95% CI or log rank P value.14 When Kaplan–Meier curves were present, we estimated the event rates from the curves using GetData Graph Digitizer software 2.26 (http://getdata-graph-digitizer.com/). In case of missing Kaplan–Meier curves, we used the reported event rates in order to calculate the IRR, as previously described.15, 16 Short‐term binary outcomes were pooled using log odds ratio (OR) with 95% CI using the generic inverse variance method.9 Random effect meta‐analysis was performed using meta and metafor packages in R (version 3.3.3 R Project for Statistical Computing).17, 18 Heterogeneity was reported as low (I2=0–25%), moderate (I2=26–50%), or high (I2 >50%).19 In random‐effects meta‐analysis, the extent of variation among the effects observed in different studies (between‐study variance) is referred to as tau2 (ie, the variance of the true effect size parameters across the population of studies). Tau2 reflects the amount of true variance (heterogeneity), while tau is the estimated standard deviation of underlying true effects across studies, and they are used to describe the distribution of true effects; if there is no variance between studies, tau2 is low (or zero).20, 21, 22 We reported tau2 values throughout tables and figures, as appropriate.

Sensitivity analysis using leave‐one‐out analysis and publication bias assessment by funnel plot and Egger's test were conducted for the primary outcome. Subgroup analysis was used to compare the relative results of RITA and RA versus SV. Meta‐regression was used to explore the effect of age, sex, diabetes mellitus, and preoperative ejection fraction on the IRR for the primary outcome.

Network meta‐analysis

Network (multiple‐treatment) meta‐analysis was conducted in R (version 3.3.3 R Project for Statistical Computing) using the “netmeta” statistical package based on the method described by Rücker.23, 24, 25 Inconsistency was evaluated with Cochran's Q.26 Pooled log IRRs with 95% CIs was used to determine the relative effect estimates of late outcomes. ORs with 95% CIs were used for the binary outcomes. A random‐effects model was preferentially used to improve the model fit, but results using a fixed model were also reported.

Inconsistency in NMA was evaluated by conducting conventional pairwise meta‐analyses and testing consistency by comparing the direct and indirect evidence. The consistency equation used was μBC=μAC−μAB, where μAB is the treatment effect for treatment B compared with treatment A.27, 28 We used Cochran's Q statistic to assess inconsistency, and the presence of P<0.05 signifies inconsistency. Statistical significance (at the 5% level) was declared when 95% CI did not cross the line of no effect. For the primary outcome, a network meta‐regression was used to relate the size of treatment effect to potential effect modifiers (mean age, percentage of female, percentage of patients with diabetes mellitus, and mean preoperative ejection fraction). Network meta‐regression was conducted using the logit transformation method with random‐effects model with no priori. The logit transformation was used as suggested by other authors.29, 30

Results

Description of the Included Studies and of the Population

A total of 2455 studies were retrieved and 35 met inclusion criteria and were included in the final meta‐analysis (Figure S1). Seven studies were international and multicenter; 11 studies were from the United States; 4 from Canada, 3 each from Italy and the United Kingdom; 2 each from Japan and Australia, and 1 each from Austria, Serbia, and Argentina (Tables 1 and 2).31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65

Table 1.

Characteristics of the Included Studies

Author/Year Study Period Mean/Median SD Follow‐Up (Years) Hospitals/Centers Type
Benedetto 201331 1996–2012 6.4±3.6 Papworth Hospital, Cambridge, England PSM
Benedetto 201432 2001–2013 4.0±3.2 Harefield Hospital, London, United Kingdom PSM
Benedetto 201733 1996–2015 10.2±4.5 Bristol Heart Institute, United Kingdom PSM
Buxton 199834 1985–1995 4.3 Austin and Repatriation Medical Center, University of Melbourne, Victoria, Australia Adjusted
Calafiore 200435 1986–1999 Overall: 7.3±4.8
RITA: 7.1±5.0
SV: 7.5±4.7
University Hospital, Torino, Italy and “G D'Annunzio” University, Chieti, Italy PSM
Carrier 200936 1995–2007 10.0 Montreal Heart Institute, Montreal, Quebec, Canada Adjusted
Cohen 200137 1994–1999 Max 3.0 Sunnybrook and Women's College Health Sciences Centre, Toronto, Canada PSM
Dewar 199538 1984–1992 4.0 Vancouver Hospital and Health Sciences Centre, University of British Columbia, Vancouver, Canada PSM
Goldman 201139 2003–2009 Max 1.0 Multicenter RCT
Goldstone 201840 2006–2011 Median arterial: 5.3 (IQR: 3.8–6.7)
Median venous: 5.2 (IQR: 3.7–6.6)
Multicenter PSM
Grau 201541 1994–2013 Overall: 10.5±5.0
RITA: 10.9±5.0
SV: 10.1±5.0
Columbia University College of Physicians and Surgeons, Ridgewood, NJ, United States PSM
Hayward 2013 (RAPCO)42 1996–2004 6 (1.8–10.4) University of Melbourne, Victoria, Australia RCT
Ioannidis 200143 1993–1996 NR Multicenter Adjusted
Janiec 201744 2001–2015 SV: 9.3 (4.2)
RA: 10.7 (4.1)
RITA: 5.5 (5.0)
Multicenter Adjusted
Kurlansky 201045 1972–1994 Overall: 11.0±0.5
RITA: 12±.0.7.0
SV: 11.0±1.0
Florida Heart Research Institute, Miami, FL, United States Adjusted
LaPar 201546 2001–2013 30.0 days VCSQI database, Virginia, United States PSM
Lin 201347 1997–2001 9.4 (5.7–11.9) Cedars‐Sinai Medical Center in Los Angeles, CA PSM
Locker 201348 1993–2009 7.6 Mayo Clinic, Rochester, MN, United States Adjusted
Lytle 200449 1971–1989 RITA: 16.2±2.4
SV: 16.3±2.5
The Cleveland Clinic Foundation, Cleveland, OH, United States PSM
Nasso 200950 2003–2006 24.1±9.8 months Multicenter RCT
Navia 201651 1996–2014 Median: 5.5 (IQR: 2.6–8.8) Instituto Cardiovascular de Buenos Aires, Buenos Aires, Argentina PSM
Parsa 201352 1984–2009 NR Duke University Medical Center, Durham, NC, United States Adjusted
Petrovic 201553 2001–2003 Max 8.0 Belgrade University School of Medicine, Belgrade, Serbia RCT
Pusca 200854 1997–2006 NR Emory University School of Medicine, Atlanta GA, United States Adjusted
Rosenblum 201655 2003–2013 Median: 2.8 (1.1–4.9) Emory University School of Medicine, Atlanta, GA, United States PSM
Ruttman 201156 2001–2010 Overall: 57.7 (3.0–112.0) months
RITA: 32.7 (3–111.0)
RA: 67.3 (3–112.0)
Innsbruck Medical University, Austria PSM
Santarpino 201057 2003–2007 3.17±0.07 Magna Graecia University of Catanzaro, Italy Adjusted
Schwann 201658 1987–2011 4.7 Multicenter PSM
Stevens 200459 1985–1995 Overall: 11.0±3.0
RITA: 8.0±2.0
SV: 12.0±3.0
Montreal Heart Institute, Montreal, Quebec, Canada Adjusted
Tarelli 200160 1988–1990 Overall: 9.2
RITA: 9.2±2.8
SV: 9.1±2.5
Varese Hospital, Varese, Italy PSM
Tranbaugh 201061 1995–2009 7.7 (0.1–13.8) Beth Israel Medical Center, New York, NY, United States PSM
Tranbaugh 201762 1995–2012 RA: 8.8±4.0
RITA: 8.9±4.9
SV: 9.1
Multicenter Adjusted
Tsuneyoshi 201563 2000–2013 6.1±7.8 “Kurashiki Central Hospital, Okayama, Japan” PSM
Yoshida 201764 1997–2007 7.5±4.4 Fukui Cardiovascular Center, Shinbo, Fukui, Japan PSM
Zacharias 200465 1996–2002 3.7±1.9 Mercy St Vincent Medical Center, Toledo, OH, United States PSM

IQR indicates interquartile range; NR, not reported; PSM, propensity score matched; RA, radial artery; RAPCO, Radial Artery Patency and Clinical Outcomes randomized trial; RCT, randomized controlled trial; RITA, right internal thoracic artery; SV, saphenous vein; VCSQI, Virginia Cardiac Services Quality Initiative.

Table 2.

Patient Demographics and Surgical Details

Author/Year Total Number Age, y (Mean±SD) Sex (Female) N (%) Ejection Fraction (Mean±SD) COPD N (%) Diabetes Mellitus N (%) RA Target Vessel Stenosis (%) OPCAB/ONCAB Details
RA SV RITA RA SV RITA RA SV RITA RA SV RITA RA SV RITA RA SV RITA
RA vs SV studies
Benedetto 201331 809 809 ··· 64±10 65±10 ··· 178 (22) 157 (19.4) ··· NR NR ··· 83 (10.3) 92 (11.4) ··· 82 (10.1) 98 (12.1) ··· NR OPCAB: RA, 27.8%
SV, 25.5%
Cohen 200137 478 956 ··· 60.7±8.8 61.2±8.7 ··· 76 (15.9) 152 (15.9) ··· NR NR ··· 40 (4.2) 23 (4.8) ··· 160 (33.5) 238 (24.9) ··· NR NR
Goldman 201139 366 367 ··· 61±8 62±8 ··· 1 (1) 5 (1) ··· NR NR ··· NR NR ··· 154 (42) 153 (42) ··· >70 OPCAB: RA, 11%
SV, 13%
Lin 201347 260 260 ··· 70.6±8.7 70.6±8.7 ··· 79 (30.4) 77 (29.4) ··· NR NR ··· 39 (15.0) 33 (12.7) ··· 101 (38.8) 91 (33.5) ··· NR OPCAB: RA, 16.5%
SV, 18.1%
Petrovic 201553 100 100 ··· 56.3±6.1 57.1±6.5 ··· 27 (27) 27 (27) ··· 48.8±10.7 48.0±10.8 ··· 8 (8) 9 (9) ··· 39 (39) 43 (43) ··· >80 NR
Santarpino 201057 150 180 ··· 72.19±9.9 70.52±9.586 ··· 20 (11.1) 49 (27.2) ··· 53.5±9.92 49.2±10.7 ··· 27 (18) 24 (13.3) ··· 49 (27.2) 36 (24) ··· >80 OPCAB: RA, 28.9%
SV, 24%
Tranbaugh 201061 862 862 ··· 60.8±8.1 60.8±9.2 ··· 203 (23.5) 185 (22.5) ··· 48.3±11.8 47.7±13.2 ··· 173 (20.1) 187 (21.7) ··· 314 (36.4) 332 (38.3) ··· >70 OPCAB: SV, 4.1%
RA, 1.3%
Yoshida 201764 91 91 ··· 64±8.8 64.7±9.7 ··· 21 (23.1%) 22 (24.2%) ··· NR NR ··· NR NR ··· 35 (38.5) 38 (41.8) ··· 87.2±13.2% OPCAB: RA, 30.9%
SV: 26.1%
Zacharias 200465 925 925 ··· 63±10 63±10 ··· 268 (28.1) 271 (28.5) ··· 49±10 49±10 ··· 174 (18.3) 177 (18.6) ··· 326 (34.2) 327 (34.3) ··· From <70 to >90 NR
RITA vs SV studies
Benedetto 201432 ··· 750 750 ··· NR (Ranges) NR (Ranges) ··· (21.2) (10.8) ··· <50% in 22.1% <50% in 13.2% ··· 10.6 7.7 ··· 31.5 15.9 ··· OPCAB: RITA, 71.7%
SV, 72.5%
Buxton 199834 ··· 1557 1269 ··· 64.9±9 58.6±9 ··· (22) (10.6) ··· <50% in 24.2% <50% in 4.9% ··· NR NR ··· 19.9 6.8 ··· NR
Calafiore 200435 ··· 570 570 ··· 60.8±9.0 60.7±8.3 ··· (17.5) (19.3) ··· 59.3±13.8 59.4±13.1 ··· 3 2.8 ··· 24.2 24.2 ··· OPCAB: RITA, 32.5%
SV, 24.2%
Carrier 200936 ··· 5420 1235 ··· 68±8 61±9 ··· 29 16 ··· NR NR ··· NR NR ··· 31 21 ··· NR
Dewar 199538 ··· 765 377 ··· NR NR ··· 16.6 15.4 ··· NR NR ··· NR NR ··· 19.3 17.7 ··· NR
Grau 201541 ··· 1006 1006 ··· 62±9 60±9 ··· 12.1 10.4 ··· 50±12 51±11 ··· 5.9 5.1 ··· 13.3 11 ··· OPCAB: RITA, 49.2%
SV 49.2%
Ioannidis 200143 ··· 830 867 ··· 65.2 (9.8) 62.0±10.3 ··· 37.3 22.6 ··· 42.0 (13.1) 46.5±13.7 ··· 19.3 13 ··· 38.4 25.6 ··· All ONCAB
Kurlansky 201045 ··· 2369 2215 ··· 67.5±9.4 62.9±10.0 ··· 25.7 14.9 ··· CAT CAT ··· NR NR ··· 27.3 20.8 ··· All ONCAB
LaPar 201546 ··· 1333 1333 ··· 59±10 56±10 ··· 18.7 14.3 ··· 55 (50–60) 55 (50–60) ··· 11.4 10.7 ··· 34.9 18.2 ··· NR
Lytle 200449 ··· 1152 1152 ··· 57.8±8.3 57.5±8.1 ··· 14 12 ··· NR NR ··· NR NR ··· 12 12 ··· NR
Navia 201651 ··· 485 485 ··· NR 63.7±9.1 ··· NR 9.8 ··· NR NR ··· NR 4.2 ··· NR 25.9 ··· ONCAB: RITA, 0.4%
SV, 61%
Parsa 201352 ··· 16 881 728 ··· 64 (median) 59 (median) ··· 28.5 19.8 ··· 52% (median) 51% (median) ··· 8.2 3.9 ··· 29.9 14.7 ··· NR
Pusca 200854 ··· 10 212 599 ··· 62.9 (10.7) 58.0±0.34 ··· 2810 (27.5) 17.4 ··· 50.1 (12.7) 51.6±11.4 ··· 1564 (15.3) 7 12 ··· 3725 (36.5) 25.2 ··· OPCAB: SV, 39%
RITA, 90%
Rosenblum 201655 ··· 306 306 ··· 63.8±10.6 59.0±10.1 ··· 28.7 15.5 ··· 51.7±12.4 52.2±11.0 ··· 6.3 1.8 ··· 43.8 27.6 ··· ONCAB: SV, 33.7%
RITA: 18.8%
Stevens 200459 ··· 2547 1835 ··· 63±9 57±9 ··· 25 12 ··· NR NR ··· 6 4 ··· 18 12 ··· NR
Tarelli 200160 ··· 150 150 ··· 59.3±8.3 56.5±8.2 ··· 17.3 7.3 ··· 54.5±13.5 57.2±13.6 ··· NR NR ··· 24.7 11.3 ··· NR (presumably all ONCAB)
RA vs RITA studies
Benedetto 201733 764 ··· 764 58±8 ··· 57±9 53 (6.9) 54 (7.1) CAT ··· CAT 36 4.7 ··· 38 5.0 49 (6.5) ··· 39 (5.1) >75 OPCAB: RA, 69%
RITA, 44.9%
Hayward 2013 (RAPCO)42 198 ··· 196 59.2 (37.9–71.0) ··· 59.5 (36.2–70.9) 23 (12) ··· 18 (9) NR ··· NR NR ··· NR 22 (11%) ··· 20 (10%) >70 All ONCAB
Ruttman 201156 277 ··· 277 57.8±9.0 ··· 56.6±9.6 28 (10.1) ··· 28 (10.1) 52.9±12.1 ··· 54.9±10.8 92 (33.2) ··· 92 (33.2) 62 (22.4) ··· 59 (21.3) NR NR
Tsuneyoshi 201563 118 ··· 118 67.9±10 ··· 68.3±8 30 (25) ··· 22 (19) CAT ··· CAT 2 (1.6) ··· 2 (1.6) 53 (45) ··· 63 (53) “Severe” All OPCAB
RA vs SV vs RITA studies
Goldstone 201840 4268 5813 1574 62.1±10.5 62.5±10.4 61.7±10.3 614 (14.5) 916 (15.8) 229 (14.3) 55.5±12.0 55.6±12.0 56.1±12.0 629 (14.8) 856 (14.7) 250 (15.6) 1525 (35.7) 2066 (35.5) 528 (33.7) NR NR
Janiec 201744 1036 46 343 862 64.5 (9.7) 66.4 (8.4) 63.9 (9.0) 277 (26.7%) 8879 (19.2%) 146 (16.9%) CAT CAT CAT 39 (5.7%) 2551 (6.9%) 59 (7.7%) 212 (20.7%) 11 077 (24.3%) 206 (24.0%) NR OPCAB: SV, 2.4%
RA, 2.4%
RITA 6.7%
Locker 201348 169 1153 (Matched) 589 NR 59±10 NR NR 187 (16.2) NR NR 58±13 NR NR 86 (7.5) NR NR 221 (19.2) NR NR OPCAB: SV, 4.4% MultArt, 3.3%
Nasso 200950 202 202 201 70.5±3.1 69.7±3.5 69.2±3.9 87 (43.1) 84 (41.6) 88 (43.8) CAT CAT 57 (28.2) 56 (27.7) 55 (27.4) 73 (36.1) 77 (38.1) 76 (37.8) >70 All ONCAB
Schwann 201658 551 551 551 58.4±10.2 60.6±10.3 59.5±9.7 72 (13) 97 (18) 77 (14) 52±10 54±10 53±11 46 (8.3) 39 (7.1) 41 (7.4) 100 (18) 94 (17) 93 (17) >75 ONCAB: RITA, 98%
RA, 96%
SV, 95%
Tranbaugh 201061 4577 7073 1674 60.3±9.7 67.4±9.9 64.9±10.3 1033 (22.6) 2448 (34.6) 460 (27.5) 49.1±10.9 47.2±12.9 46.4±14.3 781 (17.1) 1804 (25.5) 149 (8.9) 702 (37.2) 2704 (38.2) 597 (35.7) LCX:>70
RCA:>90
OPCAB: SV, 3.5%
RA, 3.0%
RITA, 1.4%

CAT indicates reported as categories; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; EF, ejection fraction; LCX, left circumflex artery territory; MultiArt, multiple arterial grafting group; NR, not reported; ONCAB, on‐pump coronary artery bypass; OPCAB, off‐pump coronary artery bypass; RA, radial artery; RCA, right coronary artery territory; RITA, right internal thoracic artery; SV, saphenous vein.

A total of 149 902 patients were included (RA, 16 201; SV, 112 018; and RITA, 21 683) from 4 RCTs (n=1932) and 31 observational studies (n=147 970). Demographics of the included studies are shown in Tables 1 and 2.

The number of patients in the individual studies ranged from 182 to 48 241 (91–4577 in the RA group, 91–46 343 in the SV group, and 118–2215 in the RITA group). The mean age ranged from 56.0 to 72.1 (56.3–72.1 years in the RA group, 57.1–70.6 years in the SV group, and 56.2–69.2 in the RITA group). Female sex ranged from 1.1 to 43.8% (1.0–43.1% in the RA group, 1.1–41.6% in the SV group, and 7.3–43.8% in the SV group). Most patients had a normal or low‐normal ejection fraction (range 42–59.4%). The incidence of diabetes mellitus ranged from 5.1 to 53.2% (6.5–45.1% in the RA group, 12.0–43.8% in the SV group, and 5.1–53.3% in the RITA group).

Pairwise Meta‐Analysis

The main results of the pairwise meta‐analysis are summarized in Table 3.

Table 3.

Outcomes Summary of the Pairwise Meta‐Analysis

Model Studies* Point Estimate 95% CI Overall Effect (Z‐Value, P Value) Heterogeneity (I2, P Value) Tau2 Interpretation
Long term mortality
RA/SV 11 0.81 0.73 to 0.90 ··· 47, 0.04 0.0110 Better in RA
RITA/SV 17 0.80 0.73 to 0.86 ··· 73, <0.01 0.0136 Better in RITA
RITA/RA 9 0.96 0.83 to 1.11 ··· 57, 0.02 0.0204 ND
ART/SV 28 0.80 0.75 to 0.85 −6.93, <0.0001 66, <0.01 0.0115 Better in ART
Perioperative DSWI
RA/SV 8 1.10 0.80 to 1.51 ··· 0, 0.48 0 ND
RITA/SV 14 1.33 1.04 to 1.69 ··· 24, 0.20 0.0463 Higher in RITA
RITA/RA 6 2.22 1.09 to 4.54 ··· 40, 0.14 0.2795 Higher in RITA
ART/SV 21 1.27 1.05 to 1.54 2.41, 0.0159 14, 0.27 0.0264 Higher in ART
Perioperative mortality
RA/SV 7 0.66 0.46 to 0.95 −2.27, 0.0234 29, 0.21 0.0599 Better in RA
RITA/SV 17 0.68 0.53 to 0.87 −3.11, 0.0019 56, 0.1327 Better in RITA
RITA/RA 7 1.76 1.21 to 2.55 2.98, 0.0029 11.7, 0.34 0.0310 Better in RA
ART/SV 24 0.68 0.55 to 0.83 −3.79, 0.0002 49.1, 0.004 0.1043 Better in ART
Perioperative stroke
RA/SV 7 0.73 0.54 to 1.00 ··· 0, 0.72 0 Better in RA
RITA/SV 11 0.85 0.62 to 1.16 ··· 36, 0.11 0.0875 ND
RITA/RA 5 0.87 0.45 to 1.68 ··· 29, 0.23 0.1653 ND
ART/SV 18 0.80 0.65 to 0.98 −2.11, 0.0350 14, 0.29 0.0266 Better in arterial
Perioperative MI
RA/SV 7 0.67 0.42 to 1.07 ··· 0, 0.56 0 ND
RITA/SV 8 0.79 0.65 to 0.96 ··· 0, 0.65 0 Better in RITA
RITA/RA 2 0.32 0.03 to 3.13 ··· 61.1, 0.11 1.67 ND
ART/SV 15 0.77 0.64 to 0.92 −2.82, 0.0048 0, 0.73 0 Better in ART

ART indicates all arterial grafts; DSWI, deep sternal wound infections; MI, myocardial infarction; ND, no difference; RA, radial artery; RITA, right internal thoracic artery; SV, saphenous vein.

*

Articles reporting the outcomes in RA, RITA, and SV cohorts were included as 3 studies (RA/SV, RITA/SV, and RITA/RA).

Incidence rate ratio was used for long‐term mortality, while odds ratio was used for operative mortality and perioperative outcomes.

At a mean follow‐up of 6.9 years, the use of any arterial graft (RA or RITA) was associated with lower long‐term mortality compared with the use of the SV (IRR, 0.80; 95% CI, 0.75–0.85). There was a significantly higher risk of DSWI (OR 1.27; 95% CI, 1.05–1.54) in the arterial graft group. Operative mortality (OR, 0.68; 95% CI, 0.55–0.83), perioperative MI (OR, 0.77; 95% CI, 0.64–0.92) and perioperative stroke (OR, 0.80; 95% CI, 0.65–0.98) were lower in the arterial graft group.

The use of the RA was associated with lower long‐term mortality (IRR, 0.81; 95% CI, 0.73–0.90) at a mean follow‐up of 8.1 years compared with the SV. Operative mortality (OR, 0.66; 95% CI, 0.46–0.95) and perioperative stroke (OR, 0.73; 95% CI, 0.54–1.00) were lower in the RA group, while the risk of perioperative MI (OR, 0.67, 95% CI, 0.42–1.07), and DSWI were similar (OR, 1.10; 95% CI, 0.80–1.51).

The use of the RITA was associated with lower long‐term mortality (IRR, 0.80; 95% CI, 0.73–0.86) at mean 8.5 years follow‐up compared with SV. Perioperative MI (OR, 0.79; 95% CI, 0.65–0.96) and operative mortality (OR, 0.68; 95% CI, 0.53–0.87) were lower in the RITA arm. There was no difference in perioperative stroke (OR, 0.85; 95% CI, 0.62–1.16), while the risk of DSWI higher in the RITA group (OR, 1.33; 95% CI, 1.04–1.69).

When directly comparing the 2 arterial grafts, the use of RITA was associated with similar long‐term mortality (IRR, 0.96; 95% CI, 0.83–1.11) at 7.1 years’ mean follow‐up compared with the RA. The risk of perioperative MI (OR, 0.32; 95% CI, 0.03–3.13) and perioperative stroke (OR, 0.87; 95% CI, 0.45–1.68) were similar between the 2 arterial grafts. There was a significantly higher risk of DSWI (OR, 2.22; 95% CI, 1.09–4.54) and operative mortality (OR, 1.76, 95% CI, 1.21–2.55) in the RITA group. When limiting the analysis to the studies where the skeletonization technique was used for ITA harvesting, no difference in DSWI between the RA and RITA groups was found (Figure S2).

A subgroup analysis for the primary outcome comparing the results of RCT versus non‐RCT studies is provided in Figure S3.

Leave‐one‐out analysis was robust for the primary outcome in the main analysis (arterial grafts versus SV (Figure S4A). Funnel plot Egger's test intercept for the primary outcome in arterial versus venous comparison was −0.64±0.46, P=0.17 (Figure S4B).

Network Meta‐Analysis

The results of the NMA are summarized in Figure and Tables S3 and S4.

Figure 1.

Figure 1

Full network meta‐analytic estimates (expressed as incidence rate ratio [IRR] and odds ratio [OR] with 95% credible interval) for the different outcomes using random and fixed models respectively. A, Long‐term mortality (SV is associated with higher long‐term mortality compared with RA; IRR=1.23, 95%CI=1.12–1.34; τ2=0.0127; I2=64%); B, Operative mortality (SV is associated with higher operative mortality compared with RA expressed as OR, 1.71; 95% CI. 1.17–2.52; τ2=0.1219; I2=48.7%); C, Perioperative MI (SV is associated with similar perioperative MI compared with RA expressed as OR=1.32, 95%CI=0.84–2.07; τ2=0.0041; I2=2.1%); D, Perioperative stroke (SV is associated with similar perioperative stroke compared with RA expressed as OR=1.30, 95%CI=0.90–1.88; τ2=0.0573; I2=22%); E, Perioperative DSWI (SV is associated with similar perioperative DSWI compared with RA expressed as OR=0.98, 95%CI=0.67–1.46; τ2=0.0671; I2=25.4%I). DSWI indicates deep sternal wound infections; MI, myocardial infarction; RA, radial artery; RITA, right internal thoracic artery; SV, saphenous vein.

The use of the SV was associated with higher late mortality (IRR, 1.23; 95% CI, 1.12–1.34) and operative mortality (OR, 1.71; 95% CI, 1.17–2.52) compared with the RA. The risk of perioperative MI (OR, 1.32; 95% CI, 0.84–2.07), perioperative stroke (OR, 1.30; 95% CI, 0.90–1.88), and DSWI (OR, 0.98; 95% CI, 0.67–1.46) was not statistically different when compared with the RA.

The use of the SV was associated with higher late mortality (IRR, 1.26; 95% CI, 1.17–1.35), operative mortality (OR, 1.45; 95% CI, 1.14–1.84), and perioperative MI (OR, 1.30; 95% CI, 1.06–1.61) compared with the RITA. The risk of perioperative stroke (OR, 1.24; 95% CI, 0.93–1.64) was not statistically different, and the risk of DSWI (OR, 0.71; 95% CI, 0.55–0.91) was lower with the SV compared with the RITA.

The use of the RITA was associated with similar late mortality (IRR, 0.98; 95% CI, 0.89–1.07) and perioperative MI (OR, 1.01; 95% CI, 0.62–1.65) compared with the RA. There was a trend toward higher risk of DSWI in the RITA group (OR, 1.39; 95% CI, 0.92–2.1), while operative mortality and stroke were similar for the 2 arteries.

At network meta‐regression, mean age, percentage of female, percentage of patients with diabetes mellitus, and mean preoperative ejection fraction were not found to significantly modify the treatment effect (Figure S5).

Discussion

The balance between possible better long‐term clinical and angiographic outcomes of arterial grafts and the potential risk of harvesting site complications and the increased technical complexity associated with their use has been the center of a continuous debate over the past 25 years.66 Also, the relative efficacy of the RITA and RA as the second arterial grafts remains controversial.7

Several pairwise meta‐analyses on the topic have been published previously.1, 67, 68 However, pairwise meta‐analyses have known limitations in terms of heterogeneity of the included studies and potential for treatment allocation bias. NMAs have been proposed to overcome the limitations of the pairwise comparison, especially when summarizing the evidence of RCTs and observational studies.9, 69 It has been suggested that NMA can be superior to classical pairwise analyses, especially in case of comparison of a new treatment to a standard one.70

This is the first NMA specifically addressing the differences in clinical outcomes according to the type of second graft used for CABG. The only published network meta‐analysis on the subject focused only on the patency rates of conduits and did not include clinical outcomes.10 Due to the demonstrated absence of a consistent correlation between angiographic failure and clinical events,11 a deeper understanding of the clinical impact of the type of second conduit used for CABG seems of major relevance.

The results of our study support the superiority of the use of a second arterial over venous graft, and suggest the equivalence in long‐term and perioperative outcomes between the RITA and RA.

The superior midterm patency rate of arterial grafts (especially the RA) has been convincingly demonstrated in RCTs and observational studies.50, 71, 72, 73, 74 A large amount of observational evidence also suggests a clinical benefit in terms of survival and event‐free survival for the use of the RA or the RITA instead of the SV as the second graft.1, 7, 75, 76 However, we have recently shown how unmatched confounders are present even in the best comparative observational studies and suggested that a treatment allocation bias may be responsible for the better clinical outcome of patients receiving more than 1 arterial graft.6

This type of bias is potentially present even in the present meta‐analysis, but the additional power and precision of NMA in defining relations and interactions between treatments from the aggregated estimates of all the available evidence should permit a more efficient comparison among different strategies.9

Our results are in line with those of a recent patient‐level meta‐analysis on the comparison between the RA and the SV.76 However, at first sight, our results appear to contradict the overall neutral findings of the ART (Arterial Revascularization Trial), where on the primary intention‐to‐treat analysis, there was no difference in survival between single and bilateral ITA grafts at 10 years (in press). However, 40% of patients in the ART received a different treatment from that initially proposed and an as‐treated analysis showed a significant survival benefit in patients receiving >1 arterial graft, consistent with the results of the current study. Difference in sample size and length of follow‐up and the fact that in observational studies the revascularization strategy is based on surgical judgment and not mandated by protocol are possible explanations for these apparent contradictions.

A key finding of this study is the demonstration of equivalence between the RITA and RA with respect to all the short‐ and long‐term clinical outcomes. Of note, in our analysis, the relative survival benefit of the RITA and RA compared with the SV were identical (SV versus RITA and RA, IRR, 1.26; 95% CI, 1.17–1.35). Although there was a trend toward higher risk of DSWI with RITA, this risk became nonsignificant in a subgroup analysis of studies where the skeletonization of ITA was employed. This finding is in accordance with what was reported by previous meta‐analyses7 and by a post hoc analysis of the ART.77

The literature on the comparison between the RITA and RA is discordant. We previously published a pairwise meta‐analysis of the propensity‐matched studies comparing the 2 arterial grafts and found that the use of the RITA was associated with a 25% relative reduction in the risk of long‐term mortality.7 The reason underlying the discrepancy between our previous meta‐analysis and the present findings is probably related to the different sample size (149 902 patients with 6.9 years of follow‐up for the present analysis versus 15 374 patients and a range of 45–168 months of follow‐up for the previous pairwise comparison). Also, our previous analysis did not include 2 recent large studies comparing the 2 arterial grafts.33, 78 Finally, the use of NMA and direct/indirect comparisons allow for better precision around estimates compared with pairwise comparisons.

Of note, in a large study the Society of Thoracic Surgeons National Database of >1.4 million patients, Schwann et al8 showed significantly higher perioperative mortality and risk of DSWI using the RITA, but not the RA, versus the SV as the second graft—findings that were also demonstrated in the present study. The authors also described a significant volume‐to‐outcome relation for the use of the RITA but not of the RA. Similarly, in a meta‐analysis of 34 bilateral internal thoracic artery (BITA) series and 27 000 BITA patients, we recently identified a highly significant BITA use‐to‐outcome relationship for long‐term survival and incidence of DSWI that was independent from the well‐known CABG volume/outcome effect.78 These findings suggest that BITA grafting may be more technically demanding than the use of the single internal thoracic artery and that a volume/outcome relation can explain the marginally increased operative risk in the RITA arm.

A key point when using the RA for CABG is the degree of target vessel stenosis. It has been shown that the patency rate of RA grafts is strongly influenced by the degree of target coronary stenosis.79, 80, 81 In fact, a target vessel stenosis >70% was a common criterion for using the RA in the studies included in this meta‐analysis (Table 2).

This study shares the usual limitations of meta‐analyses of observational studies.82 Despite statistical adjustment and the use of NMA, between‐studies heterogeneity remains a source of bias. Important details such as the etiology of follow‐up of death, the protocols used to reduce the risk of DSWI (with the exception of skeletonization of the ITA), and the incidence of repeat revascularization were not systematically retrievable and could not be included in our analyses.

Additionally, we recognize that despite including only adjusted studies, the presence of unmeasured confounders and treatment allocation biases cannot be excluded.6 However, the NMA approach utilized and the low‐moderate‐grade heterogeneity found across the studies should have attenuated these biases.

In conclusion, in an NMA of adjusted observational and randomized studies comparing the RA, the RITA, and the SV as the second conduit for CABG, we found that the use of the RITA or the RA was associated with a similar long‐term clinical benefit compared with the use of the SV. No differences in late and operative mortality and postoperative complications was found between the 2 arterial conduits, although DSWI remains a concern after BITA grafting if skeletonization is not used.

Disclosures

None.

Supporting information

Table S1. Search Strategy

Table S2. Newcastle‐Ottawa Scale for the Included Studies

Table S3. Comparison of Direct and Indirect Estimates to Assess Inconsistency Within Network Loops for the Outcomes

Table S4. Rank Scores With Probability Rank of Different Graft Groups With the Greatest Reduction in Outcomes Within the Different Treatment Groups (RITA, RA, and SV) Where the Closer to One Equates to the Probability the Therapy Leads to the Greatest Reduction

Figure S1. Preferred Reporting Items for Systematic Reviews and Meta‐Analysis flow chart of study selection.

Figure S2. A, Forest plot showing subgroup differences for skeletonization on deep sternal wound infection (DSWI) in RITA vs RA/SVG pairwise comparisons (subgroup difference P=0.1933); B, Forest plot showing subgroup differences for skeletonization on deep sternal wound infection (DSWI) in RITA vs SVG pairwise comparisons (subgroup difference P=0.4194); C, Forest plot showing subgroup differences for skeletonization on deep sternal wound infection (DSWI) in RITA vs RA pairwise comparisons (subgroup difference P=0.2786). RA indicates radial artery; RITA, right internal artery; SV, saphenous vein.

Figure S3. Long‐term mortality for arterial grafts (RA/RITA) vs SV in RCT vs non‐RCT trials (subgroup difference P=0.4897). ART indicates all arterial grafts; RA, radial artery; RITA, right internal thoracic artery; SV, saphenous vein.

Figure S4. Leave one out (A) and funnel plot (B) for the primary analysis. RA indicates radial artery; RITA, right internal artery; SV, saphenous vein.

Figure S5. Network meta‐regression for long term mortality. A, Mean age; B, Female percent; C, Diabetes mellitus percent; D, Ejection fraction (EF) percent.

(J Am Heart Assoc. 2019;8:e010839 DOI: 10.1161/JAHA.118.010839.)

References

  • 1. Buttar SN, Yan TD, Taggart DP, Tian DH. Long‐term and short‐term outcomes of using bilateral internal mammary artery grafting versus left internal mammary artery grafting: a meta‐analysis. Heart. 2017;103:1419–1426. [DOI] [PubMed] [Google Scholar]
  • 2. Authors/Task Force Members , Windecker S, Kolh P, Alfonso F, Collet J‐P, Cremer J, Falk V, Filippatos G, Hamm C, Head SJ, Jüni P, Kappetein AP, Kastrati A, Knuuti J, Landmesser U, Laufer G, Neumann F‐J, Richter DJ, Schauerte P, Sousa Uva M, Stefanini GG, Taggart DP, Torracca L, Valgimigli M, Wijns W, Witkowski A. 2014 ESC/EACTS guidelines on myocardial revascularization: the Task Force on Myocardial Revascularization of the European Society of Cardiology (ESC) and the European Association for Cardio‐Thoracic Surgery (EACTS). Developed with the special contribution of the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur Heart J. 2014;35:2541–2619. [DOI] [PubMed] [Google Scholar]
  • 3. Levine GN, Bates ER, Bittl JA, Brindis RG, Fihn SD, Fleisher LA, Granger CB, Lange RA, Mack MJ, Mauri L, Mehran R, Mukherjee D, Newby LK, O'Gara PT, Sabatine MS, Smith PK, Smith SC. 2016 ACC/AHA guideline focused update on duration of dual antiplatelet therapy in patients with coronary artery disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines: an update of the 2011 ACCF/AHA/SCAI Guideline for Percutaneous Coronary Intervention, 2011 ACCF/AHA Guideline for Coronary Artery Bypass Graft Surgery, 2012 ACC/AHA/ACP/AATS/PCNA/SCAI/STS Guideline for the Diagnosis and Management of Patients With Stable Ischemic Heart Disease, 2013 ACCF/AHA Guideline for the Management of ST‐Elevation Myocardial Infarction, 2014 AHA/ACC Guideline for the Management of Patients With Non‐ST‐Elevation Acute Coronary Syndromes, and 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery. Circulation. 2016;134:e123–e155. [DOI] [PubMed] [Google Scholar]
  • 4. Aldea GS, Bakaeen FG, Pal J, Fremes S, Head SJ, Sabik J, Rosengart T, Kappetein AP, Thourani VH, Firestone S, Mitchell JD; Society of Thoracic Surgeons . The Society of Thoracic Surgeons clinical practice guidelines on arterial conduits for coronary artery bypass grafting. Ann Thorac Surg. 2016;101:801–809. [DOI] [PubMed] [Google Scholar]
  • 5. Taggart DP, Altman DG, Gray AM, Lees B, Gerry S, Benedetto U, Flather M; ART Investigators . Randomized trial of bilateral versus single internal‐thoracic‐artery grafts. N Engl J Med. 2016;375:2540–2549. [DOI] [PubMed] [Google Scholar]
  • 6. Gaudino M, Di Franco A, Rahouma M, Tam DY, Iannaccone M, Deb S, D'Ascenzo F, Abouarab AA, Girardi LN, Taggart DP, Fremes SE. Unmeasured confounders in observational studies comparing bilateral versus single internal thoracic artery for coronary artery bypass grafting: a meta‐analysis. J Am Heart Assoc. 2018;7:e008010 DOI: 10.1161/JAHA.117.008010. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7. Benedetto U, Gaudino M, Caputo M, Tranbaugh RF, Lau C, Di Franco A, Ng C, Girardi LN, Angelini GD. Right internal thoracic artery versus radial artery as the second best arterial conduit: insights from a meta‐analysis of propensity‐matched data on long‐term survival. J Thorac Cardiovasc Surg. 2016;152:1083–1091.e15. [DOI] [PubMed] [Google Scholar]
  • 8. Schwann TA, Habib RH, Wallace A, Shahian DM, O'Brien S, Jacobs JP, Puskas JD, Kurlansky PA, Engoren MC, Tranbaugh RF, Bonnell MR. Operative outcomes of multiple‐arterial versus single‐arterial coronary bypass grafting. Ann Thorac Surg. 2018;105:1109–1119. [DOI] [PubMed] [Google Scholar]
  • 9. Song F, Harvey I, Lilford R. Adjusted indirect comparison may be less biased than direct comparison for evaluating new pharmaceutical interventions. J Clin Epidemiol. 2008;61:455–463. [DOI] [PubMed] [Google Scholar]
  • 10. Benedetto U, Raja SG, Albanese A, Amrani M, Biondi‐Zoccai G, Frati G. Searching for the second best graft for coronary artery bypass surgery: a network meta‐analysis of randomized controlled trials. Eur J Cardiothorac Surg. 2015;47:59–65; discussion 65. [DOI] [PubMed] [Google Scholar]
  • 11. Gaudino M, Antoniades C, Benedetto U, Deb S, Di Franco A, Di Giammarco G, Fremes S, Glineur D, Grau J, He G‐W, Marinelli D, Ohmes LB, Patrono C, Puskas J, Tranbaugh R, Girardi LN, Taggart DP; ATLANTIC (Arterial Grafting International Consortium) Alliance . Mechanisms, consequences, and prevention of coronary graft failure. Circulation. 2017;136:1749–1764. [DOI] [PubMed] [Google Scholar]
  • 12. Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gøtzsche PC, Ioannidis JPA, Clarke M, Devereaux PJ, Kleijnen J, Moher D. The PRISMA statement for reporting systematic reviews and meta‐analyses of studies that evaluate health care interventions: explanation and elaboration. Ann Intern Med. 2009;151:W65–W94. [DOI] [PubMed] [Google Scholar]
  • 13. Wells G, Shea B, O'Connell D, Peterson J, Welch V, Losos M. Newcastle‐Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in metaanalysis. 3rd Symp Syst Rev Basics Improv Qual Impact. 2000.
  • 14. Parmar MK, Torri V, Stewart L. Extracting summary statistics to perform meta‐analyses of the published literature for survival endpoints. Stat Med. 1998;17:2815–2834. [DOI] [PubMed] [Google Scholar]
  • 15. Yanagawa B, Verma S, Jüni P, Tam DY, Mazine A, Puskas JD, Friedrich JO. A systematic review and meta‐analysis of in situ versus composite bilateral internal thoracic artery grafting. J Thorac Cardiovasc Surg. 2017;153:1108–1116.e16. [DOI] [PubMed] [Google Scholar]
  • 16. Tierney JF, Stewart LA, Ghersi D, Burdett S, Sydes MR. Practical methods for incorporating summary time‐to‐event data into meta‐analysis. Trials. 2007;8:16. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17. Schwarzer G. meta: an R package for meta‐analysis. R News. 2007;7:40–45. [Google Scholar]
  • 18. Viechtbauer W. Conducting meta‐analyses in R with the metafor package. J Stat Softw. 2010;36:1–48. [Google Scholar]
  • 19. Higgins JPT, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta‐analyses. BMJ. 2003;327:557–560. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20. Deeks J, Higgins J, Altman DG. Analysing data and undertaking meta‐analyses In: Sally G, Julian H, eds. Cochrane Handbook for Systematic Reviews of Interventions: Cochrane Book Series. England: John Wiley & Sons; 2008:243–296. [Google Scholar]
  • 21. Borenstein M, Hedges L, Higgins J, Rothstein H. Introduction to Meta‐Analysis. West Sussex, England: John Wiley & Sons; 2009. [Google Scholar]
  • 22. Borenstein M, Hedges L, Rothstein H. A basic introduction to fixed‐effect and random‐effects models for meta‐analysis. Res Synth Methods. 2010;1:97–111. [DOI] [PubMed] [Google Scholar]
  • 23. Rücker G, Schwarzer G, Krahn U, König J. Netmeta: network meta‐analysis using frequentist methods. R package version 0.9‐7. [Internet]. 2017. Available at: https://CRAN.R-project.org/package=netmeta. Accessed September 3, 2018.
  • 24. Rücker G, Schwarzer G, König J. Netmeta: network meta‐analysis with R. Version 0.6‐0 2014. 12. [Internet]. 2014. Available at: http://cran.r-project.org/web/packages/netmeta/index.html. Accessed September 3, 2018.
  • 25. Rücker G. Network meta‐analysis, electrical networks and graph theory. Res Synth Methods. 2012;3:312–324. [DOI] [PubMed] [Google Scholar]
  • 26. Krahn U, Binder H, König J. A graphical tool for locating inconsistency in network meta‐analyses. BMC Med Res Methodol. 2013;13:35. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27. Higgins JP, Whitehead A. Borrowing strength from external trials in a meta‐analysis. Stat Med. 1996;15:2733–2749. [DOI] [PubMed] [Google Scholar]
  • 28. Higgins JP. Identifying and addressing inconsistency in network meta‐analysis. Cochrane comparing multiple interventions methods group Oxford training event. 2013; Available at: https://methods.cochrane.org/sites/methods.cochrane.org.cmi/files/public/uploads/S9-L%20Identifying%20and%20addressing%20inconsistency%20in%20network%20meta-analysis.pdf. Accessed September 3, 2018.
  • 29. Qin G, Hotilovac L. Comparison of non‐parametric confidence intervals for the area under the ROC curve of a continuous‐scale diagnostic test. Stat Methods Med Res. 2008;17:207–221. [DOI] [PubMed] [Google Scholar]
  • 30. Snell KI, Ensor J, Debray TP, Moons KG, Riley RD. Meta‐analysis of prediction model performance across multiple studies: which scale helps ensure between‐study normality for the C‐statistic and calibration measures? Stat Methods Med Res. 2018;27:3505–3522. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31. Benedetto U, Codispoti M. Age cutoff for the loss of survival benefit from use of radial artery in coronary artery bypass grafting. J Thorac Cardiovasc Surg. 2013;146:1078–1084; discussion 1084–1085. [DOI] [PubMed] [Google Scholar]
  • 32. Benedetto U, Amrani M, Gaer J, Bahrami T, de Robertis F, Simon AR, Raja SG; Harefield Cardiac Outcomes Research Group . The influence of bilateral internal mammary arteries on short‐ and long‐term outcomes: a propensity score matching in accordance with current recommendations. J Thorac Cardiovasc Surg. 2014;148:2699–2705. [DOI] [PubMed] [Google Scholar]
  • 33. Benedetto U, Caputo M, Gaudino M, Marsico R, Rajakaruna C, Bryan A, Angelini GD. Right internal thoracic artery or radial artery? A propensity‐matched comparison on the second‐best arterial conduit. J Thorac Cardiovasc Surg. 2017;153:79–88.e4. [DOI] [PubMed] [Google Scholar]
  • 34. Buxton BF, Komeda M, Fuller JA, Gordon I. Bilateral internal thoracic artery grafting may improve outcome of coronary artery surgery. Risk‐adjusted survival. Circulation. 1998;98:II1–II6. [PubMed] [Google Scholar]
  • 35. Calafiore AM, Di Giammarco G, Teodori G, Di Mauro M, Iacò AL, Bivona A, Contini M, Vitolla G. Late results of first myocardial revascularization in multiple vessel disease: single versus bilateral internal mammary artery with or without saphenous vein grafts. Eur J Cardiothorac Surg. 2004;26:542–548. [DOI] [PubMed] [Google Scholar]
  • 36. Carrier M, Cossette M, Pellerin M, Hébert Y, Bouchard D, Cartier R, Demers P, Jeanmart H, Pagé P, Perrault LP. Statin treatment equalizes long‐term survival between patients with single and bilateral internal thoracic artery grafts. Ann Thorac Surg. 2009;88:789–795; discussion 795. [DOI] [PubMed] [Google Scholar]
  • 37. Cohen G, Tamariz MG, Sever JY, Liaghati N, Guru V, Christakis GT, Bhatnagar G, Cutrara C, Abouzahr L, Goldman BS, Fremes SE. The radial artery versus the saphenous vein graft in contemporary CABG: a case‐matched study. Ann Thorac Surg. 2001;71:180–185; discussion 185–186. [DOI] [PubMed] [Google Scholar]
  • 38. Dewar LR, Jamieson WR, Janusz MT, Adeli‐Sardo M, Germann E, MacNab JS, Tyers GF. Unilateral versus bilateral internal mammary revascularization. Survival and event‐free performance. Circulation. 1995;92:II8–II13. [DOI] [PubMed] [Google Scholar]
  • 39. Goldman S, Sethi GK, Holman W, Thai H, McFalls E, Ward HB, Kelly RF, Rhenman B, Tobler GH, Bakaeen FG, Huh J, Soltero E, Moursi M, Haime M, Crittenden M, Kasirajan V, Ratliff M, Pett S, Irimpen A, Gunnar W, Thomas D, Fremes S, Moritz T, Reda D, Harrison L, Wagner TH, Wang Y, Planting L, Miller M, Rodriguez Y, Juneman E, Morrison D, Pierce MK, Kreamer S, Shih M‐C, Lee K. Radial artery grafts vs saphenous vein grafts in coronary artery bypass surgery: a randomized trial. JAMA. 2011;305:167–174. [DOI] [PubMed] [Google Scholar]
  • 40. Goldstone AB, Chiu P, Baiocchi M, Wang H, Lingala B, Boyd JH, Woo YJ. Second arterial versus venous conduits for multivessel coronary artery bypass surgery in California. Circulation. 2018;137:1698–1707. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41. Grau JB, Johnson CK, Kuschner CE, Ferrari G, Shaw RE, Brizzio ME, Zapolanski A. Impact of pump status and conduit choice in coronary artery bypass: a 15‐year follow‐up study in 1412 propensity‐matched patients. J Thorac Cardiovasc Surg. 2015;149:1027–1033.e2. [DOI] [PubMed] [Google Scholar]
  • 42. Hayward PA, Buxton BF. Mid‐term results of the Radial Artery Patency and Clinical Outcomes randomized trial. Ann Cardiothorac Surg. 2013;2:458–466. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43. Ioannidis JP, Galanos O, Katritsis D, Connery CP, Drossos GE, Swistel DG, Anagnostopoulos CE. Early mortality and morbidity of bilateral versus single internal thoracic artery revascularization: propensity and risk modeling. J Am Coll Cardiol. 2001;37:521–528. [DOI] [PubMed] [Google Scholar]
  • 44. Janiec M, Dimberg A, Nazari Shafti TZ, Lagerqvist B, Lindblom RPF. No improvements in long‐term outcome after coronary artery bypass grafting with arterial grafts as a second conduit: a Swedish nationwide registry study. Eur J Cardiothorac Surg. 2018;53:448–454. [DOI] [PubMed] [Google Scholar]
  • 45. Kurlansky PA, Traad EA, Dorman MJ, Galbut DL, Zucker M, Ebra G. Thirty‐year follow‐up defines survival benefit for second internal mammary artery in propensity‐matched groups. Ann Thorac Surg. 2010;90:101–108. [DOI] [PubMed] [Google Scholar]
  • 46. LaPar DJ, Crosby IK, Rich JB, Quader MA, Speir AM, Kern JA, Tribble C, Kron IL, Ailawadi G; Investigators for the Virginia Cardiac Surgery Quality Initiative . Bilateral internal mammary artery use for coronary artery bypass grafting remains underutilized: a propensity‐matched multi‐institution analysis. Ann Thorac Surg. 2015;100:8–14; discussion 14–15. [DOI] [PubMed] [Google Scholar]
  • 47. Lin J, Cheng W, Czer LS, De Robertis MA, Mirocha J, Ruzza A, Kass RM, Khoynezhad A, Ramzy D, Esmailian F, Trento A. Coronary artery bypass graft surgery using the radial artery as a secondary conduit improves patient survival. J Am Heart Assoc. 2013;2:e000266 DOI: 10.1161/JAHA.113.000266. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 48. Locker C, Schaff HV, Dearani JA, Daly RC. Improved late survival with arterial revascularization. Ann Cardiothorac Surg. 2013;2:467–474. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 49. Lytle BW, Blackstone EH, Sabik JF, Houghtaling P, Loop FD, Cosgrove DM. The effect of bilateral internal thoracic artery grafting on survival during 20 postoperative years. Ann Thorac Surg. 2004;78:2005–2012; discussion 2012–2014. [DOI] [PubMed] [Google Scholar]
  • 50. Nasso G, Coppola R, Bonifazi R, Piancone F, Bozzetti G, Speziale G. Arterial revascularization in primary coronary artery bypass grafting: direct comparison of 4 strategies–results of the Stand‐in‐Y Mammary Study. J Thorac Cardiovasc Surg. 2009;137:1093–1100. [DOI] [PubMed] [Google Scholar]
  • 51. Navia DO, Vrancic M, Piccinini F, Camporrotondo M, Dorsa A, Espinoza J, Benzadon M, Camou J. Myocardial revascularization exclusively with bilateral internal thoracic arteries in T‐graft configuration: effects on late survival. Ann Thorac Surg. 2016;101:1775–1781. [DOI] [PubMed] [Google Scholar]
  • 52. Parsa CJ, Shaw LK, Rankin JS, Daneshmand MA, Gaca JG, Milano CA, Glower DD, Smith PK. Twenty‐five‐year outcomes after multiple internal thoracic artery bypass. J Thorac Cardiovasc Surg. 2013;145:970–975. [DOI] [PubMed] [Google Scholar]
  • 53. Petrovic I, Nezic D, Peric M, Milojevic P, Djokic O, Kosevic D, Tasic N, Djukanovic B, Otasevic P. Radial artery vs saphenous vein graft used as the second conduit for surgical myocardial revascularization: long‐term clinical follow‐up. J Cardiothorac Surg. 2015;10:127. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 54. Pusca SV, Kilgo PD, Vega JD, Cooper WA, Vassiliades TA, Chen EP, Lattouf OM, Guyton RA, Puskas JD. Propensity‐score analysis of early outcomes after bilateral versus single internal thoracic artery grafting. Innovations (Phila). 2008;3:19–24. [DOI] [PubMed] [Google Scholar]
  • 55. Rosenblum JM, Harskamp RE, Hoedemaker N, Walker P, Liberman HA, de Winter RJ, Vassiliades TA, Puskas JD, Halkos ME. Hybrid coronary revascularization versus coronary artery bypass surgery with bilateral or single internal mammary artery grafts. J Thorac Cardiovasc Surg. 2016;151:1081–1089. [DOI] [PubMed] [Google Scholar]
  • 56. Ruttmann E, Fischler N, Sakic A, Chevtchik O, Alber H, Schistek R, Ulmer H, Grimm M. Second internal thoracic artery versus radial artery in coronary artery bypass grafting: a long‐term, propensity score‐matched follow‐up study. Circulation. 2011;124:1321–1329. [DOI] [PubMed] [Google Scholar]
  • 57. Santarpino G, Onorati F, Cristodoro L, Scalas C, Mastroroberto P, Renzulli A. Radial artery graft flowmetry is better than saphenous vein on postero‐lateral wall. Int J Cardiol. 2010;143:158–164. [DOI] [PubMed] [Google Scholar]
  • 58. Schwann TA, Hashim SW, Badour S, Obeid M, Engoren M, Tranbaugh RF, Bonnell MR, Habib RH. Equipoise between radial artery and right internal thoracic artery as the second arterial conduit in left internal thoracic artery‐based coronary artery bypass graft surgery: a multi‐institutional study. Eur J Cardiothorac Surg. 2016;49:188–195. [DOI] [PubMed] [Google Scholar]
  • 59. Stevens LM, Carrier M, Perrault LP, Hébert Y, Cartier R, Bouchard D, Fortier A, El‐Hamamsy I, Pellerin M. Single versus bilateral internal thoracic artery grafts with concomitant saphenous vein grafts for multivessel coronary artery bypass grafting: effects on mortality and event‐free survival. J Thorac Cardiovasc Surg. 2004;127:1408–1415. [DOI] [PubMed] [Google Scholar]
  • 60. Tarelli G, Mantovani V, Maugeri R, Chelazzi P, Vanoli D, Grossi C, Ornaghi D, Panisi P, Sala A. Comparison between single and double internal mammary artery grafts: results over ten years. Ital Heart J. 2001;2:423–427. [PubMed] [Google Scholar]
  • 61. Tranbaugh RF, Dimitrova KR, Friedmann P, Geller CM, Harris LJ, Stelzer P, Cohen B, Hoffman DM. Radial artery conduits improve long‐term survival after coronary artery bypass grafting. Ann Thorac Surg. 2010;90:1165–1172. [DOI] [PubMed] [Google Scholar]
  • 62. Tranbaugh RF, Schwann TA, Swistel DG, Dimitrova KR, Al‐Shaar L, Hoffman DM, Geller CM, Engoren M, Balaram SK, Puskas JD, Habib RH. Coronary artery bypass graft surgery using the radial artery, right internal thoracic artery, or saphenous vein as the second conduit. Ann Thorac Surg. 2017;104:553–559. [DOI] [PubMed] [Google Scholar]
  • 63. Tsuneyoshi H, Komiya T, Shimamoto T, Sakai J, Hiraoka T, Kawashima T, Muraoka G, Fujimoto M, Yamanaka K. The second best arterial graft to the left coronary system in off‐pump bypass surgery: a propensity analysis of the radial artery with a proximal anastomosis to the ascending aorta versus the right internal thoracic artery. Gen Thorac Cardiovasc Surg. 2015;63:335–342. [DOI] [PubMed] [Google Scholar]
  • 64. Yoshida S, Numata S, Tsutsumi Y, Monta O, Yamazaki S, Seo H, Samura T, Ohashi H. Short‐ and long‐term results of radial artery and saphenous vein grafts in the right coronary system: a propensity‐matched study. Surg Today. 2017;47:335–343. [DOI] [PubMed] [Google Scholar]
  • 65. Zacharias A, Habib RH, Schwann TA, Riordan CJ, Durham SJ, Shah A. Improved survival with radial artery versus vein conduits in coronary bypass surgery with left internal thoracic artery to left anterior descending artery grafting. Circulation. 2004;109:1489–1496. [DOI] [PubMed] [Google Scholar]
  • 66. Dai C, Lu Z, Zhu H, Xue S, Lian F. Bilateral internal mammary artery grafting and risk of sternal wound infection: evidence from observational studies. Ann Thorac Surg. 2013;95:1938–1945. [DOI] [PubMed] [Google Scholar]
  • 67. Yi G, Shine B, Rehman SM, Altman DG, Taggart DP. Effect of bilateral internal mammary artery grafts on long‐term survival: a meta‐analysis approach. Circulation. 2014;130:539–545. [DOI] [PubMed] [Google Scholar]
  • 68. Takagi H, Goto S, Watanabe T, Mizuno Y, Kawai N, Umemoto T. A meta‐analysis of adjusted hazard ratios from 20 observational studies of bilateral versus single internal thoracic artery coronary artery bypass grafting. J Thorac Cardiovasc Surg. 2014;148:1282–1290. [DOI] [PubMed] [Google Scholar]
  • 69. Greco T, Landoni G, Biondi‐Zoccai G, D'Ascenzo F, Zangrillo A. A Bayesian network meta‐analysis for binary outcome: how to do it. Stat Methods Med Res. 2016;25:1757–1773. [DOI] [PubMed] [Google Scholar]
  • 70. Chalmers I, Matthews R. What are the implications of optimism bias in clinical research? Lancet. 2006;367:449–450. [DOI] [PubMed] [Google Scholar]
  • 71. Gaudino M, Tondi P, Benedetto U, Milazzo V, Flore R, Glieca F, Ponziani FR, Luciani N, Girardi LN, Crea F, Massetti M. Radial artery as a coronary artery bypass conduit: 20‐year results. J Am Coll Cardiol. 2016;68:603–610. [DOI] [PubMed] [Google Scholar]
  • 72. Buxton BF, Raman JS, Ruengsakulrach P, Gordon I, Rosalion A, Bellomo R, Horrigan M, Hare DL. Radial artery patency and clinical outcomes: five‐year interim results of a randomized trial. J Thorac Cardiovasc Surg. 2003;125:1363–1371. [DOI] [PubMed] [Google Scholar]
  • 73. Glineur D, D'hoore W, de Kerchove L, Noirhomme P, Price J, Hanet C, El Khoury G. Angiographic predictors of 3‐year patency of bypass grafts implanted on the right coronary artery system: a prospective randomized comparison of gastroepiploic artery, saphenous vein, and right internal thoracic artery grafts. J Thorac Cardiovasc Surg. 2011;142:980–988. [DOI] [PubMed] [Google Scholar]
  • 74. Deb S, Cohen EA, Singh SK, Une D, Laupacis A, Fremes SE; RAPS Investigators . Radial artery and saphenous vein patency more than 5 years after coronary artery bypass surgery: results from RAPS (Radial Artery Patency Study). J Am Coll Cardiol. 2012;60:28–35. [DOI] [PubMed] [Google Scholar]
  • 75. Taggart DP, Altman DG, Flather M, Gerry S, Gray A, Lees B, Benedetto U; ART (Arterial Revascularization Trial) Investigators . Associations between adding a radial artery graft to single and bilateral internal thoracic artery grafts and outcomes: insights from the Arterial Revascularization Trial. Circulation. 2017;136:454–463. [DOI] [PubMed] [Google Scholar]
  • 76. Gaudino M, Benedetto U, Fremes S, Biondi‐Zoccai G, Sedrakyan A, Puskas JD, Angelini GD, Buxton B, Frati G, Hare DL, Hayward P, Nasso G, Moat N, Peric M, Yoo KJ, Speziale G, Girardi LN, Taggart DP; RADIAL Investigators . Radial‐artery or saphenous‐vein grafts in coronary‐artery bypass surgery. N Engl J Med. 2018;378:2069–2077. [DOI] [PubMed] [Google Scholar]
  • 77. Benedetto U, Altman DG, Gerry S, Gray A, Lees B, Pawlaczyk R, Flather M, Taggart DP; Arterial Revascularization Trial Investigators . Pedicled and skeletonized single and bilateral internal thoracic artery grafts and the incidence of sternal wound complications: insights from the Arterial Revascularization Trial. J Thorac Cardiovasc Surg. 2016;152:270–276. [DOI] [PubMed] [Google Scholar]
  • 78. Gaudino M, Bakaeen F, Benedetto U, Rahouma M, Di Franco A, Tam D, Iannaccone M, Schwann T, Habib R, Ruel M, Puskas J, Sabik J, Girardi L, Taggart D, Fremes S. Use rate and outcome in bilateral internal thoracic artery grafting: insights from a systematic review and meta‐analysis. J Am Heart Assoc. 2018;7:e009361 DOI: 10.1161/JAHA.118.009361. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 79. Maniar HS, Sundt TM, Barner HB, Prasad SM, Peterson L, Absi T, Moustakidis P. Effect of target stenosis and location on radial artery graft patency. J Thorac Cardiovasc Surg. 2002;123:45–52. [DOI] [PubMed] [Google Scholar]
  • 80. Hashimoto H, Isshiki T, Ikari Y, Hara K, Saeki F, Tamura T, Yamaguchi T, Suma H. Effects of competitive blood flow on arterial graft patency and diameter. Medium‐term postoperative follow‐up. J Thorac Cardiovasc Surg. 1996;111:399–407. [DOI] [PubMed] [Google Scholar]
  • 81. Manninen HI, Jaakkola P, Suhonen M, Rehnberg S, Vuorenniemi R, Matsi PJ. Angiographic predictors of graft patency and disease progression after coronary artery bypass grafting with arterial and venous grafts. Ann Thorac Surg. 1998;66:1289–1294. [DOI] [PubMed] [Google Scholar]
  • 82. Song F, Xiong T, Parekh‐Bhurke S, Loke YK, Sutton AJ, Eastwood AJ, Holland R, Chen Y‐F, Glenny A‐M, Deeks JJ, Altman DG. Inconsistency between direct and indirect comparisons of competing interventions: meta‐epidemiological study. BMJ. 2011;343:d4909. [DOI] [PMC free article] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Table S1. Search Strategy

Table S2. Newcastle‐Ottawa Scale for the Included Studies

Table S3. Comparison of Direct and Indirect Estimates to Assess Inconsistency Within Network Loops for the Outcomes

Table S4. Rank Scores With Probability Rank of Different Graft Groups With the Greatest Reduction in Outcomes Within the Different Treatment Groups (RITA, RA, and SV) Where the Closer to One Equates to the Probability the Therapy Leads to the Greatest Reduction

Figure S1. Preferred Reporting Items for Systematic Reviews and Meta‐Analysis flow chart of study selection.

Figure S2. A, Forest plot showing subgroup differences for skeletonization on deep sternal wound infection (DSWI) in RITA vs RA/SVG pairwise comparisons (subgroup difference P=0.1933); B, Forest plot showing subgroup differences for skeletonization on deep sternal wound infection (DSWI) in RITA vs SVG pairwise comparisons (subgroup difference P=0.4194); C, Forest plot showing subgroup differences for skeletonization on deep sternal wound infection (DSWI) in RITA vs RA pairwise comparisons (subgroup difference P=0.2786). RA indicates radial artery; RITA, right internal artery; SV, saphenous vein.

Figure S3. Long‐term mortality for arterial grafts (RA/RITA) vs SV in RCT vs non‐RCT trials (subgroup difference P=0.4897). ART indicates all arterial grafts; RA, radial artery; RITA, right internal thoracic artery; SV, saphenous vein.

Figure S4. Leave one out (A) and funnel plot (B) for the primary analysis. RA indicates radial artery; RITA, right internal artery; SV, saphenous vein.

Figure S5. Network meta‐regression for long term mortality. A, Mean age; B, Female percent; C, Diabetes mellitus percent; D, Ejection fraction (EF) percent.


Articles from Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease are provided here courtesy of Wiley

RESOURCES