Single versus multiple arterial coronary artery bypass grafting in men and women: results from Polish National Registry of Cardiac Surgery Procedures

Abstract

Background:

The objective of this multicenter study aimed to investigate the impact of sex on long-term survival among patients with multivessel coronary artery disease undergoing coronary artery bypass grafting (CABG) using multiple arterial grafting (MAG) or a single artery with saphenous vein grafts.

Materials and methods:

Data were obtained from the Polish National Registry of Cardiac Surgery Procedures database. This study included 81 136 patients who underwent CABG for multivessel disease between January 2012 and December 2020 (22.9 were women and 77.1% were men). MAG was performed in 8.3 and 11.7% of female and male patients, respectively. A 1:1 propensity score (PS)-matching was performed. Long-term mortality was compared between matched groups of men and women. Subgroup analyses of patients aged <70 and ≥70 years, with an ejection fraction (EF) >40% and ≤40%, and with and without diabetes, obesity, peripheral artery disease (PAD), or chronic lung disease (CLD) were performed separately in women and men.

Results:

MAG was associated with lower long-term mortality than saphenous vein grafts in 1528 PS-matched female pairs [hazard ratio (HR): 0.74; 95% CI: 0.59–0.92; P=0.007) and 7283 PS-matched male pairs (HR: 0.80; 95% CI: 0.72–0.88; P<0.001). Subgroup analyses confirmed the results among female patients aged <70 years, with diabetes and EF >40%, and without PAD or CLD, and of male patients aged <70 and ≥70 years; with EF >40%; with or without diabetes, obesity, or PAD; and without CLD.

Conclusions:

In patients undergoing CABG, MAG was associated with significantly improved survival in both sexes. The long-term benefits of MAG observed across subgroups of men and women support the consideration of a multiarterial revascularization strategy for a broader spectrum of patients.

Introduction

Highlights

• Multiple arterial grafting (MAG) had lower long-term mortality than single artery with saphenous vein grafts (SAG) in men.

• MAG had lower long-term mortality than SAG in women.

• MAG had lower long-term mortality than SAG in female patients younger than 70 years, with diabetes, with an EF higher than 40%, without peripheral artery disease, and without chronic lung disease.

• MAG had lower long-term mortality than SAG in patients aged <70 and ≥70 years, with EF >40%, without chronic lung disease, and with or without diabetes, obesity, and peripheral artery disease.

Coronary artery bypass grafting (CABG) is considered to be the treatment of choice in patients with multivessel or left main coronary artery disease (CAD); revascularization of the stenotic left anterior descending artery with the left internal thoracic artery is the gold standard of care^1,2. The effect of patient sex on this treatment has been underappreciated, and despite major advances in treating CAD, little progress has been made in improving the outcomes of CAD in women compared to men³. Recent studies evaluated the impact of sex on outcomes following CABG and showed that women have worse early and long-term outcomes compared to men following CABG^4,5. The sex-related outcome differences after CABG could be explained by the fact that women with CABG have markedly more adverse risk factors, smaller coronary vessels, and advanced CAD^4,5.

Multiple studies showed the benefits of multiple arterial grafting (MAG) using the radial artery (RA) and right internal thoracic artery in reducing long-term mortality and major adverse cardiac and cerebral events (MACCE)^6–10. Yet, the strategies for surgical coronary revascularization may differ between sexes, and women remain underrepresented, accounting for 14–30% of the patients enrolled in the randomized controlled trials (RCTs) comparing revascularization strategies^11,12. Furthermore, the effect of MAG on the long-term outcomes in women undergoing CABG remains controversial^13,14. Therefore, this multicenter study aimed to investigate the impact of sex on long-term survival among patients undergoing CABG using MAG or a single artery with saphenous vein grafts (SAG) in Poland.

Materials and methods

Study design

Data were collected and reported in accordance with the Polish National Registry of Cardiac Surgery Procedures (KROK Registry) database (www. krok. csioz. gov. pl), which is mandatory for all cardiac surgeries in Poland. Centers enrolling patients in the KROK registry are required to transfer data concerning every cardiac surgical procedure to the central database and are financially liable for data integrity and completeness. The database contains detailed information on preoperative, intraoperative, and postoperative hospital variables for all patients undergoing cardiac surgery. Data were collected either at presentation or by a physician’s review of the hospital records and were forwarded to the KROK registry. The forms were reviewed for clinical and analytical internal validity. This study was designed according to the Strengthening the Reporting of Cohort, Cross-Sectional, and Case–Control Studies in Surgery (STROCCS) guidelines¹⁵. Between January 2012 and December 2020, we identified 105 391 adult patients undergoing isolated CABG using the KROK participant user account; of these, we excluded patients who underwent CABG for single-vessel disease (n=13 344), were managed exclusively with venous conduits (n=4839), were hemodynamically unstable (i.e. preoperative shock, inotropic, or mechanical circulatory support (MCS) requirement; n=2548), had missing data (n=2021), had previously undergone heart surgery (n=1157), and were undergoing multivessel minimally invasive CABG (n=346). Figure 1 shows the flowchart of patient information. This study was approved by the Institutional Review Board of the University of Zielona Gora (RCM-CM-KBUZ.031.35.2023), Poland. The requirement for individual consent for anonymous data analysis was waived by the committee.

Figure 1.

Flow diagram detailing selection of patients within each group. The diagram presents included and excluded patients as well as number of patients before and after propensity score matching. CABG, coronary artery bypass grafting; MAG, multiarterial graft; SAG, single arterial graft with veins.

Study endpoints and definitions

The primary endpoint was late survival in men and women receiving MAG vs those receiving SAG. Survival data were obtained from the National Health Fund (an obligatory nationwide public insurer in Poland) and incorporated into the KROK registry.

Short-term outcomes included 30-day mortality, in-hospital myocardial infarction (MI), in-hospital cerebral adverse events (CAEs), reoperation for bleeding, new-onset renal replacement therapy (RRT), postoperative MCS, and sternal wound infection (SWI). MI was defined according to the Fourth Universal definition¹⁶. CAE was defined as the development of a new permanent or transient (lasting up to 72 h) neurologic deficit, confirmed by stroke team-member assessment of the patient and computed tomography, MRI, or autopsy examination. MCS was defined as the implantation of any MCS device intraoperatively or postoperatively. SWI was defined as a sternal infection involving the muscle, bone, and/or mediastinum requiring surgical intervention and treatment with antibiotics. Data regarding early postoperative outcomes and long-term survival were available for all patients in the study.

Statistical analysis

Continuous variables are expressed as means±SD and categorical variables as numbers and percentages. For continuous data, Student’s t-test was used for between-group comparisons, while categorical variables were compared with the Pearson-χ ² test. A total of 1.91% of patients with missing data regarding any of the variables were excluded from the study. Variables with missing data, had missing data below 1% (renal failure, age, sex, BMI, conduit type). All models were developed based on complete records.

Propensity score (PS)-matching was used to reduce the impact of confounders inherent in observational studies. PSs were generated separately for women and men using a multivariate logistic regression model based on all preoperative and intraoperative variables (Table S1). Patients were then matched in a 1:1 ratio using a caliper-matching method without replacement with a caliper width of 0.2 SD of the logit of the PS. The balance of covariates was tested using standardized mean difference (SMD). Statistical guidelines suggest a meaningful covariate balance of the variables to generate PS with SMD ≤0.1 between the two groups. Table 1 shows the baseline and operative characteristics after PS-matching in both sexes. Figures S1 and S2 show SMD plots before and after PS-matching in women and men, respectively. Matched data were analyzed using procedures for matched analyses. Short-term outcomes were analyzed separately in women and men using conditional logit analysis, and odds ratios (ORs) were estimated for postoperative short-term outcomes in the matched sample^17–22.

Table 1.

Baseline and operative characteristics after propensity score matching in both sexes.

	Women			Men
Baseline characteristics	MAG (n=1528)	SAG (n=1528)	P	SMD	MAG (n=7283)	SAG (n=7283)	P	SMD
Age (years)	64.0±9.17	64.1±9.01	0.88	0.005	59.7±8.70	59.7±8.33	0.98	<0.001
Age ≥70 years	452 (29.6)	462 (30.2)	0.72	0.014	955 (13.1)	956 (13.1)	>0.99	<0.001
BMI (kg/m2)	28.2±4.68	28.2±4.59	0.95	0.002	28.3±3.94	28.4±4.05	0.51	0.011
BMI ≥30 kg/m2	506 (33.1)	513 (33.6)	0.81	0.010	2278 (31.3)	2266 (31.1)	0.84	0.004
NYHA III–IV	218 (14.3)	202 (13.2)	0.43	0.030	774 (10.6)	801 (11.0)	0.48	0.012
Recent MI	426 (27.9)	414 (27.1)	0.65	0.018	2163 (29.7)	2092 (28.7)	0.20	0.021
Previous PCI	344 (22.5)	350 (22.9)	0.82	0.009	2062 (28.3)	2076 (28.5)	0.81	0.004
Smoker	268 (17.5)	271 (17.7)	0.92	0.005	1787 (24.5)	1818 (25.0)	0.56	0.010
Diabetes	550 (36.0)	562 (36.8)	0.67	0.016	2107 (28.9)	2149 (29.5)	0.45	0.013
History of CAEs	41 ( 2.7)	36 (2.4)	0.64	0.021	181 ( 2.5)	187 ( 2.6)	0.79	0.005
Hypertension	1342 (87.8)	1339 (87.6)	0.91	0.006	6127 (84.1)	6125 (84.1)	0.98	0.001
Hyperlipidemia	1044 (68.3)	1043 (68.3)	>0.99	0.001	4822 (66.2)	4812 (66.1)	0.87	0.003
PAD	300 (19.6)	308 (20.2)	0.75	0.013	1130 (15.5)	1172 (16.1)	0.35	0.016
CLD	109 ( 7.1)	100 ( 6.5)	0.56	0.023	492 ( 6.8)	497 ( 6.8)	0.89	0.003
AF	66 ( 4.3)	60 ( 3.9)	0.64	0.020	248 ( 3.4)	233 ( 3.2)	0.51	0.012
LM disease	437 (28.6)	474 (31.0)	0.15	0.053	2258 (31.0)	2282 (31.3)	0.68	0.007
EF (%)	54.1±9.51	54.0±9.49	0.76	0.011	51.9±9.76	51.6±9.72	0.07	0.030
EF ≤40%	152 ( 9.9)	149 ( 9.8)	0.90	0.007	1059 (14.5)	1129 (15.5)	0.11	0.027
Nonelective surgery	654 (42.8)	654 (42.8)	>0.99	<0.001	3023 (41.5)	2974 (40.8)	0.41	0.014
Renal impairment	631 (41.3)	643 (42.1)	0.68	0.016	2027 (27.8)	2071 (28.4)	0.42	0.013
Moderate renal impairment	562 (36.8)	544 (35.6)	0.52	0.025	1638 (22.5)	1648 (22.6)	0.85	0.003
Severe renal impairment	62 ( 4.1)	83 ( 5.4)	0.08	0.065	368 ( 5.1)	403 ( 5.5)	0.20	0.021
On dialysis	7 ( 0.5)	16 ( 1.0)	0.09	0.068	21 ( 0.3)	20 ( 0.3)	>0.99	0.003
OPCAB	1004 (65.7)	1006 (65.8)	0.97	0.003	4354 (59.8)	4406 (60.5)	0.38	0.015
Number of grafts	2.5±0.73	2.5±0.66	0.69	0.014	2.6±0.79	2.6±0.72	0.42	0.013

Data are expressed as mean±SD or n (%), unless otherwise indicated.

Renal impairment defined as eGFR<85 ml/min/1.73 m², Moderate and severe renal impairment defined as eGFR>50<85 ml/min/1.73 m² and eGFR<50 ml/min/1.73 m², respectively.

AF, atrial fibrillation; OPCAB, Off-pump coronary artery bypass grafting; CAEs, cerebral adverse events; CLD, chronic lung disease; EF, ejection fraction; eGFR, estimated glomerular filtration rate; LM, left main disease; MAG, multiple arterial grafting; MI, myocardial infarction; NYHA, New York Heart Association; PAD, peripheral artery disease; PCI, percutaneous coronary intervention; SAG, single arterial graft + saphenous vein graft; SMD, standardized mean difference.

The Kaplan–Meier curve was plotted to estimate patient survival. For the matched cohorts, the Cox proportional hazard model stratified on matched pairs was conducted. The hazard ratios (HRs) and corresponding 95% CIs were reported. All P values were from two-sided tests, and results were deemed statistically significant at P <0.05. Patients were censored at the end of the follow-up (31 May 2022).

Subgroup analyses of patients aged <70 and ≥70 years, with ejection fraction (EF) >40% and ≤40%, and with and without diabetes, obesity, peripheral artery disease (PAD), and chronic lung disease (CLD) were performed separately in women and men. New PS matches utilizing the aforementioned method were used to create matched pairs for each subgroup among women and men. Tables S2–S25 present the preoperative and intraoperative variables after matching with the corresponding SMD in each subgroup of women and men. A Cox proportional hazard model stratified by matched pairs was used for each subgroup. HRs and corresponding 95% CIs were reported. Figure 2 shows the caterpillar plot of the subgroup analyses of long-term mortality after MAG and SAG in women and men.

Figure 2.

Risk of mortality in women and men who underwent multiple arterial graft (MAG) versus single arterial graft (SAG) in the propensity score matched patients and in the propensity matched subgroup of patients younger than age 70 years and aged 70 years or older, diabetic and non diabetic patients, obese and nonobese patients, ejection-fraction (EF) above 40% and equal or below 40%, with and without peripheral artery disease (PAD), and with and without chronic lung disease (CLD), separately in women and men.

All statistical analyses were carried out in R (R Core Team; 2021) version 4.2.2. R software is a language and environment for statistical computing (R Foundation for Statistical Computing; https://www.R-project.org/).

Results

We identified 81 136 patients who underwent CABG for multivessel disease between January 2012 and December 2020; of these, 18 528 (22.9%) were women and 62 608 (77.1%) were men. Among female patients, 1534 (8.3%) received MAG, and 16 994 (91.7%) received SAG. Among male patients, 7296 (11.7%) underwent MAG, and 55 312 (88.3%) underwent SAG. The median follow-up time was 5.7 years (interquartile range: 3.4–7.9 years) for women and 5.4 years (interquartile range: 3.2–7.7 years) for men.

Table S1 shows the baseline and operative characteristics of the patients included in the study before matching. Patients undergoing MAG, both women and men, were younger, had lower BMIs, lower incidence of renal failure, lower previous CAEs, and higher EF, and were more likely to be smokers and have left main disease than those receiving SAG. Regarding operative variables, patients undergoing MAG were more likely to undergo off-pump coronary surgery and consequently received fewer grafts than those undergoing SAG. PS-matching selected 1528 pairs of women and 7283 pairs of men; both groups were comparable for all characteristics and well-balanced (SMD <0.1) (Table 1) (Figs. S1, S2).

The short-term outcomes of the matched cohorts of women and men are summarized in Table 2. MAG and SAG had comparable outcomes in women and men in terms of 30-day mortality, in-hospital MI, in-hospital CAEs, new-onset RRT, rethoracotomy due to bleeding, and MCS device implantation. However, increased incidence of SWI was observed in male patients receiving MAG (conditional logit, OR: 1.28; 95% CI: 1.02–1.61) but not in female patients receiving MAG when compared to patients receiving SAG (conditional logit, OR: 1.10; 95% CI: 0.71–1.68). In the matched cohorts, 67.9% of male patients who underwent MAG received bilateral internal thoracic arteries (BITA)+/-RA or saphenous vein graft (SVG), and 60.8% of female patients who underwent MAG received BITA+/- RA or SVG. BITA was associated with an increased risk of SWI compared to SAG in men (conditional logit, OR: 1.5; 95% CI: 1.16–1.96) but not in women (conditional logit, OR: 1.48; 95% CI: 0.87–2.51). No difference was observed in SWI between MAG when compared to SAG when RA was used as a second graft, both in women (conditional logit, OR: 0.61; 95% CI: 0.28–1.29) and men (conditional logit, OR: 0.81; 95% CI: 0.52–1.27).

Table 2.

Short-term outcomes in propensity matched cohorts.

Women	MAG (n=1528)	SAG (n=1528)	Conditional logit, OR (95% CI)
30-day mortality	33 (2.1)	34 (2.2)	0.97 (0.60–1.57)
Perioperative MI	26 (1.7)	28 (1.8)	0.92 (0.53–1.60)
CAEs	16 (1.0)	21 (1.4)	0.73 (0.37–1.47)
New onset RRT	21 (1.4)	16 (1.0)	1.31 (0.68–2.52)
SWI	46 (3.0)	42 (2.7)	1.10 (0.71–1.68)
MCS	26 (1.7)	22 (1.4)	1.20 (0.66–2.17)
Rethoracotomy due to bleeding	23 (1.5)	38 (2.5)	0.60 (0.35–1.02)
Men	MAG (n=7283)	SAG (n=7283)
30-day mortality	87 (1.2)	66 (0.9)	1.33 (0.96–1.84)
Perioperative MI	73 (1.0)	70 (0.9)	1.04 (0.75–1.45)
CAEs	59 (0.8)	55 (0.8)	1.08 (0.73–1.57)
New onset RRT	56 (0.8)	52 (0.7)	1.08 (0.73–1.57)
SWI	173 (2.4)	135 (1.9)	1.28 (1.02–1.61)
MCS	56 (0.8)	78 (1.1)	0.71 (0.50–1.01)
Rethoracotomy due to bleeding	198 (2.7)	224 (3.1)	0.88 (0.72–1.07)

Data are displayed as n (%).

CAEs, cerebral adverse events; MAG, multiarterial grafts; MCS, mechanical circulatory support, MI, myocardial infarction; OR, odds-ratio; RRT, renal replacement therapy, SAG, single-arterial-graft+saphenous-vein; SWI, sternal wound infection.

In 1528 PS-matched female pairs, survival probabilities at 3, 6, and 9 years were 92 vs. 91%, 87 vs. 82%, and 79 vs. 71% in the MAG and SAG groups, respectively. MAG was associated with lower long-term mortality than SAG (HR: 0.74; 95% CI: 0.59–0.92; P=0.007; Fig. 3A). Subgroup analyses confirmed the results in female patients aged <70 years with diabetes, with EF >40%, and without PAD or CLD. MAG was associated with lower long-term mortality in 1073 PS-matched pairs of a subgroup of women aged <70 years (HR: 0.70; 95% CI: 0.52–0.92; P=0.01), 546 PS-matched pairs of a subgroup of women with diabetes (HR: 0.67; 95% CI: 0.47–0.96; P=0.03), 1373 PS-matched pairs of a subgroup of women with EF >40% (HR: 0.76; 95% CI: 0.60–0.96; P=0.02), 1225 PS-matched pairs of a subgroup of women without PAD (HR: 0.76; 95% CI: 0.59–0.99; P=0.04), and 1419 PS-matched pairs of a subgroup of women without CLD (HR: 0.79; 95% CI: 0.63–0.99; P=0.04). No differences were observed between MAG and SAG in PS-matched pairs of subgroups of women aged ≥70 years, without diabetes, with or without obesity, and with EF ≤40%, PAD, and CLD (Fig. 2).

Figure 3.

Kaplan–Meier survival curve probabilities after propensity score weighting in women (A) and in men (B). MAG, multiarterial grafts, SAG, single artery+saphenous vein graft.

In 7283 PS-matched male pairs, survival probabilities at 3, 6, and 9 years were 93 vs. 92%, 87 vs. 84%, and 79 vs. 73% in the MAG and SAG groups, respectively. MAG was associated with lower long-term mortality than SAG (HR: 0.80; 95% CI: 0.72–0.88; P<0.001; Fig. 3B). Subgroup analyses confirmed the results in male patients aged <70 and ≥70 years, without CLD, with EF >40%, and with or without diabetes, obesity, and PAD. MAG was associated with lower long-term mortality in 6324 PS-matched pairs of a subgroup of men aged <70 years (HR: 0.79; 95% CI: 0.70–0.90; P<0.001), 953 PS-matched pairs of the subgroup of men aged ≥70 years (HR: 0.81; 95% CI: 0.66–0.98; P=0.03), 2099 and 5167 PS-matched pairs of subgroups of men with and without diabetes, respectively (HR: 0.77; 95% CI: 0.64–0.93; P=0.006 and HR: 0.83; 95% CI: 0.73–0.94; P=0.005, respectively), 2275 and 4997 PS-matched pairs of subgroups of men with and without obesity, respectively (HR: 0.80; 95% CI: 0.66–0.96; P=0.01 and HR: 0.82; 95% CI: 0.73–0.93; P=0.002, respectively), 6222 PS-matched pairs of the subgroup of men with EF >40% (HR: 0.78; 95% CI: 0.69–0.8; P<0.001), 1130 and 6150 PS-matched pairs of subgroups of men with and without PAD, respectively (HR: 0.75; 95% CI: 0.61–0.92; P=0.006 and HR: 0.82; 95% CI: 0.73–0.93; P=0.001, respectively), and 6789 PS-matched pairs of the subgroup of men without CLD (HR: 0.82; 95% CI: 0.73–0.91; P<0.001). No difference was observed between MAG and SAG in PS-matched pairs of a subgroup of men with EF ≤40% and CLD (Fig. 2).

Discussion

In the present PS-matched study of patients with CAD who underwent CABG in Poland from 2012 to 2020, we focused on the prognostic impact of sex on long-term survival after CABG using MAG and SAG. MAG was associated with improved long-term survival in both men and women. Subgroup analyses confirmed the results in women aged <70 years, with diabetes, with EF >40%, and without PAD and CLD. In contrast, in male patients, subgroup analyses confirmed the results in men, irrespective of age, or the presence of diabetes, obesity, and PAD. No difference was observed between MAG and SAG in subgroups of men and women with EF ≤40% and CLD.

The effect of sex has traditionally been underappreciated, and despite major advances in CAD treatment, little progress has been made in improving the outcomes of CAD in women compared to that in men³. In a pooled analysis of four RCTs, Gaudino et al.⁵. studied the effect of sex on outcomes after CABG and showed that over 5 years of follow-up, women had a higher risk of MACCE but similar mortality compared with men. However, these differences in MACCE were not seen in patients aged ≥75 years. Although the benefit of a revascularization strategy using MAG has been reported in several studies^6–10, only a few have examined the association between sex and outcomes of MAG vs. SAG, and the results remain controversial. Schwann et al.²³. showed superior late survival when RA was used as a second arterial conduit in men (HR: 0.65; 95% CI: 0.54–0.70; P<0.001) and women (HR: 0.75; 95% CI: 0.57–0.79; P=0.045). In a PS-matched study, Dimitrova et al.²⁴ supported these findings and showed superior 15-year survival with RA as a second graft compared to SAG in women (70 vs. 58%; P log-rank = 0.018, respectively). In contrast, in a PS-matched cohort from New York’s Cardiac Surgery Reporting System database, Gaudino et al.¹³ showed that overall, MAG benefited male patients regarding survival compared to SAG (HR: 0.80; 95% CI: 0.73–0.87; P<0.001) rather than female patients (HR: 0.99; 5% CI: 0.84–1.15; P=0.85). However, when stratified by the estimated risk of death, MAG was associated with better survival and a lower rate of MACCE among patients of both sexes with low-risk but not high-risk. Tam et al.¹⁴ showed that MAG in women is associated with longer survival at 10 years (HR: 0.85; 95% CI: 0.74–0.98) and higher freedom from MACCE (HR: 0.85; 95% CI: 0.76–0.95) compared to SAG. A meta-analysis of six studies performed by Robinson et al.²⁵ showed that MAG was associated with reduced long-term mortality in women compared to SAG (HR: 0.85; 95% CI: 0.76–0.96). Our study is consistent with the findings and showed that both sexes benefit more from MAG than from SAG.

Several reports have shown sex differences in the choice of revascularization strategies in patients undergoing CABG. Jabagi et al.²⁶ showed that women received fewer multiple arterial coronary revascularizations than men, as in other studies^13,14,27. Consistent with the literature, our study found that the use of MAG was significantly more frequent in men than in women (11.7 vs. 8.3%; P<0.001), respectively. Several factors may influence the potential underutilization of MAG in women compared with that in men. First, the concern of increased SWI, which has been shown in several studies that the female sex is a strong predictor of SWI, especially when BITA is used^14,28,29. In contrast to these reports, our analysis showed that MAG in female patients had insignificant differences when compared to SAG in terms of SWI, regardless of whether the BITA or RA was used as the second arterial conduit; however, this was not the case in men: BITA was associated with an increased risk of SWI but not when the RA was grafted. Second, studies suggest that female patients are referred later for CABG and present with more advanced disease^30,31. Moreover, female patients have smaller native coronary vessels on average, which may be more challenging to graft^32,33 and might adversely impact early morbidity and mortality. Therefore, these factors of delayed diagnosis, with a tendency toward a higher burden of comorbidities, older age, obesity, diabetes, smaller coronary vessels, and an increased risk of SWI, may explain the underutilization of MAG in women compared to men. Our study suggests that despite the higher burden of comorbidities in women than in men, surgeons should consider the MAG approach given its long-term benefits and similar early outcomes compared to SAG.

In a PS-matched study, Pu et al.³⁴. showed that MAG was associated with a significantly lower mortality rate regardless of diabetes, obesity, or renal disease and in patients with EF >35% compared to SAG. However, no difference was observed in patients with severely impaired EF and in patients aged ≥70 years with PAD or CLD. Schwann et al.³⁵ reported that MAG with RA was associated with long-term survival in patients with and without obesity. In contrast, in a PS-matched study based on data from the New Jersey registry, Alsaleh et al.³⁶ showed that MAG was associated with lower long-term mortality, a lower risk of repeated revascularization, and MACCE in patients with diabetes compared to SAG. Moreover, subgroup analyses in patients with diabetes confirmed the results in patients aged below and above 70 years as well as in male and female patients. In our study, we performed subgroup analyses in both men and women and found that MAG was associated with improved survival in women aged <70 years, with diabetes, with EF >40%, and without PAD and CLD compared to SAG; in contrast, in male patients, subgroup analyses confirmed the results in men, irrespective of age, or the presence of diabetes, obesity, and PAD. Conversely, no difference was observed between MAG and SAG in subgroups of men and women with impaired EF (≤40%) and CLD.

The ongoing ‘Randomization of Single vs. Multiple Arterial Grafts in Women: The ROMA:Women Trial’ (NCT04124120) will hopefully provide further evidence for this debate³⁷. This large trial aims to compare a multiple vs. single arterial strategy and will include all women enrolled in the main ROMA trial (NCT03217006)³⁸, and add 1310 women to the sample. The findings of ROMA:Women will provide important data regarding the optimal strategy for surgical coronary revascularization in women undergoing CABG.

This study had some limitations. The main limitation was its inherently retrospective nature, including potential selection bias regarding patients who underwent MAG or SAG. A PS-matching procedure was performed to reduce the impact of potential confounders. However, it should be noted that even in a well-balanced matching study, the results could reflect the effects of unknown or unmeasured confounders. The choice of revascularization strategy is often subjective and may be affected by several prognostically important factors that were unavailable in our registry. Factors such as the size and quality of the harvested grafts, their coronary targets, and patient frailty are unmeasured and important for the surgeon’s choice of revascularization strategy. Moreover, an important potential confounder is the surgeon’s or study center’s influence, which is unknown and may differ. In addition, no data were available regarding the cause of death, MACCE, the need for repeated revascularization, or graft patency. Notably, the power of the study to detect differences in survival in subgroup analyses, especially in women, was very low because of the small sample size. Lastly, we did not analyze the outcomes of different conduits concerning the grafted territory.

Conclusions

In this retrospective study of data from a mandatory Polish registry, multiple arterial grafts were associated with significantly improved survival rates in male and female patients. The long-term benefits consistently observed across subgroups of men and women support the consideration of a multiarterial revascularization strategy for a broader spectrum of patients. Evidence from further prospective studies, including the ROMA and ROMA:Women trials^37,38, is needed to provide a definitive answer to this debate.

Ethical approval

The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Institutional Ethics Committee of University of Zielona Gora (RCM-CM-KBUZ.031.35.2023).

Consent

Individual patient consent was waived because of the study’s retrospective design and the data collection from routine care.

Sources of funding

This study received no specific grant from any funding agency in the public, commercial, or not for profit sectors.

Author contribution

S.S.A., G.H., B.P., R.C., and T.H.: study concept and design; S.S.A., G.H., B.P., M.J., T.H., M.B., M.D., J.R., M.C., M.K., L.A., K.W., W.G., J.P., P.B., P.S., B.J.M., R.C., and T.H.: acquisition of data; S.S.A., G.H., B.P., T.H., J.R., M.K., R.C., and T.H.: analysis and interpretation of data; S.S.A., G.H., B.P., M.J., T.H., M.B., M.D., J.R., M.C., M.K., L.A., K.W., W.G., J.P., P.B., P.S., B.J.M., R.C., and T.H.: drafting of the manuscript; S.S.A., G.H., B.P., M.J., T.H., M.B., M.D., J.R., M.C., M.K., L.A., K.W., W.G., J.P., P.B., P.S., B.J.M., R.C., and T.H.: critical revision of the manuscript. All authors have read and agreed to the published version of the manuscript.

Conflicts of interest disclosure

The authors have nothing to disclose.

Research registration unique identifying number (UIN)

1. Name of the registry: Researchregistry.com.

2. Unique identifying number or registration ID: researchregistry9694.

3. Hyperlink to your specific registration (must be publicly accessible and will be checked): https://www.researchregistry.com/browse-theregistry#home/registrationdetails/6552906729a6e9002ac7857d/.

Guarantor

Sleiman Sebastian Aboul-Hassan.

Data availability statement

Data available upon reasonable request.

Provenance and peer review

Not applicable.