Endoscopic versus open radial artery harvesting for coronary artery bypass grafting: an updated systematic review, meta-analysis, and GRADE assessment

Abstract

Background

Endoscopic radial artery harvesting (ERAH) is a minimally invasive alternative to open radial artery harvesting (ORAH) for coronary artery bypass grafting (CABG), though concerns persist regarding graft patency and neurological outcomes.

Methods

PubMed, Embase, Cochrane Library, and ClinicalTrials.gov were searched through February 21, 2026. Randomized controlled trials and propensity-matched observational studies were included. Risk of bias was assessed using ROB 2 and the Newcastle-Ottawa Scale; certainty of evidence was evaluated using GRADE. Pooled risk ratios and mean differences with 95% confidence intervals were calculated using a random-effects model.

Results

ERAH significantly reduced wound complications (RR = 0.61, 95% CI: 0.39–0.96) and wound infections (RR = 0.57, 95% CI: 0.35–0.93), though this benefit did not persist in RCT-only analysis. Neurological complications were reduced after sensitivity analysis (RR = 0.44, 95% CI: 0.34–0.57). Graft patency was comparable (RR = 1.01, 95% CI: 0.90–1.14), with no significant differences in mortality, MACCE, or myocardial infarction. Observational data showed modest reductions in cardiopulmonary bypass time and hospital stay.

Conclusions

ERAH demonstrates comparable graft patency and major clinical outcomes to ORAH. Donor-site benefits suggested by observational studies are not consistently supported by randomized evidence. Large trials with standardized outcomes and long-term follow-up are needed.

Trial registration

PROSPERO, CRD420261334767.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s12872-026-06326-2.

Introduction

Coronary artery disease (CAD) remains the leading cause of cardiovascular mortality, accounting for nearly 9 million deaths annually [1]. Against this backdrop, coronary artery bypass grafting (CABG) continues to play a pivotal role in revascularization and is the most frequently performed major cardiac surgery worldwide, particularly in patients with multivessel or left main disease, diabetes, or impaired left ventricular function [2, 3]. The long-term success of CABG is closely dependent on conduit selection, which critically influences graft patency and clinical outcomes. While the left internal thoracic artery to the left anterior descending artery remains the gold standard, attention has increasingly shifted toward optimizing additional conduits. In this context, the radial artery (RA) has emerged as the preferred second arterial graft due to its superior durability and clinical performance. Supporting this, a patient-level meta-analysis of six randomized controlled trials demonstrated that RA use significantly reduces graft occlusion, all-cause mortality, myocardial infarction, and repeat revascularization at five years compared with saphenous vein grafts [4].

Open radial artery harvesting (ORAH) is the traditional technique, performed through a longitudinal forearm incision. Although it provides direct visualization and facilitates careful conduit dissection, ORAH is associated with donor-site complications, including wound infection, hematoma, and neurological deficits [5].

Endoscopic radial artery harvesting (ERAH) was developed as a minimally invasive alternative to reduce forearm morbidity while preserving conduit quality. Current evidence suggests that ERAH achieves comparable graft patency and mortality to ORAH, while reducing the incidence of wound infections and neurological complications [5, 6]. However, prior studies are limited by heterogeneity, short follow-up durations, small sample sizes, and the inclusion of unadjusted observational cohorts, raising concerns about selection bias and the reliability of pooled estimates [6, 7].

In light of these limitations, and with the emergence of several recent large randomized controlled trials and propensity-matched studies [8–10], an updated meta-analysis (update to Rahouma et al. [5]) is warranted. Importantly, existing meta-analyses on this topic are now over five years old and may not adequately reflect contemporary surgical practice, particularly given ongoing refinements in endoscopic harvesting techniques, improved operator experience, and evolving perioperative care. As such, their findings may have limited applicability to current clinical settings. By incorporating more recent, higher-quality evidence, performing subgroup analyses by study design, and applying the GRADE framework, this study aims to provide a more robust and contemporary comparison of ERAH and ORAH. It evaluates perioperative, safety, and efficacy outcomes to offer an updated and clinically relevant assessment of these techniques in patients undergoing CABG.

Methods

Study design and protocol registration

This meta-analysis was performed following the recommendations of the Cochrane Handbook for Systematic Review of Interventions and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [11]. These protocols governed the study’s design, execution, and data synthesis. The review was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the following ID: CRD420261334767.

Data resources and search strategy

To identify relevant studies evaluating endoscopic versus open radial artery harvesting for coronary artery bypass grafting (CABG), we performed an electronic search of PubMed, Embase, the Cochrane Library and Clinicaltrials.gov. The search encompassed all literature from November 1, 2016 till February 21, 2026. The following Medical Subject Headings (MeSH) were used: “radial artery”, “harvest”, “minimally invasive” and “conventional”. The reference lists of included studies were also screened to ensure a comprehensive retrieval of studies. Complete search strategies, including all keywords and Boolean operators, are provided in Supplementary Table 1.

Study selection and eligibility criteria

Upon completion of the electronic search, all the selected studies were imported into Rayyan AI for screening, where duplicates were identified and removed. The remaining studies were screened based on their titles and abstracts by two independent reviewers. Records meeting the initial criteria underwent a comprehensive full-text evaluation to confirm eligibility. Any conflicts were resolved through discussion with a third reviewer.

Inclusion was restricted to studies meeting the following criteria: (1) Study design: randomized controlled trials and propensity matched cohort/observational studies, (2) Population: patients undergoing coronary artery bypass grafting (CABG), (3) Intervention: Endoscopic radial artery harvesting (ERAH), (4) Control: open or conventional radial artery harvesting (ORAH), (5) Outcomes: reporting sufficient baseline data and at least one relevant outcome.

Exclusion criteria included: (1) cohort studies without propensity score matching, (2) studies that were reviews, conference abstracts, case reports, case series, reviews, meta-analyses, editorials, unpublished manuscripts or articles not in English, (3) Ineligible patient cohorts, (4) republished literature.

Data extraction and outcomes

Data from the main text, tables and figures of included studies was extracted independently by two authors using a pre-piloted Microsoft Excel spreadsheet. Any disagreements arising were resolved by a third author. The following baseline characteristics were extracted: study ID, type of study, country, sample size, regimen, male percentage, study duration and follow up. The patient characteristics included: age, left ventricular ejection fraction (LVEF) and comorbidities including hypertension, diabetes mellitus, peripheral artery occlusion disease and prior myocardial infarction.

The outcomes extracted were as follows: wound complications, wound infection rate, patency rate, in-hospital/ 30-day mortality, long term mortality (over 1 year), neurological complications defined as the impairment of sensitivity and mobility of the harvest sites, length of hospital stay, freedom from MACCE (Major Adverse Cardiac & Cerebrovascular Events) and length of harvested artery. The operative outcomes were aortic cross clamp time, cardiopulmonary bypass (CPB) time and harvest time. The data regarding adverse effects were also extracted and included myocardial infarction, septicemia, hand ischemia, renal failure and pain. Moreover, the outcome data was extracted as mean and standard deviation in case of continuous outcomes and in the form of events and total for dichotomous outcomes.

Quality assessment

The Revised Cochrane Risk of Bias Tool for Randomized Trials (ROB 2) was used to evaluate the quality of the included randomized controlled trials [12]. Two independent reviewers scrutinized each study across five domains: the randomization process, deviations from intended interventions, missing outcome data, measurement of outcomes, and selection of reported results. Overall bias for each study was classified as low, some concerns, or high risk. Disagreements were resolved via consensus with a third reviewer.

On the other hand, cohort studies were appraised using the Newcastle Ottawa Quality Assessment Scale (NOS), which assesses bias across three domains: Selection of the participants, comparability of study groups and assessment of outcomes. Each study was awarded a maximum of nine stars, with higher scores indicating high quality studies. The evaluation of each study was performed individually by two reviewers and conflicts were resolved through discussion.

GRADE assessment

We employed the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework to evaluate the certainty of evidence, utilizing the GRADEpro Guideline Development Tool [13]. Two independent reviewers appraised the evidence categorizing it as high, moderate, low, or very low certainty. In cases of disagreement, a final rating was reached through discussion and consensus.

Data analysis

Statistical analysis was performed using Review Manager (RevMan) 5.4. Treatment effects were expressed as pooled risk ratio (RR) for dichotomous data and mean differences (MD) for continuous data with 95% confidence intervals for both. Outcomes for which reported data were in the form of risk ratios and 95% confidence intervals were analyzed using the generic inverse variance method. Cochran Q Test and I² statistics were used to monitor heterogeneity, with P < 0.10 or I² > 50% suggesting significant inconsistency [14]. The DerSimonian and Laird random-effects model was used for all outcomes [15]. A two-tailed p-value < 0.05 indicated statistical significance for clinical endpoints. A sensitivity analysis for the outcomes of length of artery and neurological complications was performed using the leave-one-out method by systematically excluding each study and re-analyzing the data to verify the stability of the pooled results and confirm that the aggregate estimates were not skewed by any individual study. Moreover, subgroup analyses were performed based on study design (RCT or cohort) for all outcomes and publication year (pre-2020 vs. ≥2020) for outcomes with sufficient data.

Assessment of publication bias for the outcome of wound complications was not performed, as although ten studies reported this endpoint, two studies had zero events in both arms and were not contributory to effect estimation; thus, fewer than ten studies were effectively available for meaningful evaluation, rendering publication bias assessment unreliable.

Results

Search results

This updated systematic review and meta-analysis builds upon the prior work of Rahouma et al. [5], which included six studies. A comprehensive literature search of PubMed (n = 108), Embase (n = 185), and the Cochrane Library (n = 21), along with clinical trial registries (n = 7), yielded a total of 321 records. After removal of 148 duplicates, 173 records underwent title and abstract screening, of which 154 were excluded. Nineteen reports were sought for full-text retrieval, all of which were successfully obtained and assessed for eligibility. Fourteen reports were subsequently excluded, including 12 that did not meet the eligibility criteria and 2 conference abstracts. Ultimately, five new studies met the inclusion criteria and were incorporated into the updated analysis, resulting in a total of eleven studies included in the final review [8–10, 16−23].It is worth noting that two studies; Burns et al. [19] and Kiaii et al. [23], corresponded to the same trial registration number but reported distinct outcomes, and were thus treated as separate study reports in the analysis. A detailed overview is shown in the PRISMA flow diagram (Fig. 1).

Fig. 1.

PRISMA flow diagram

Study and baseline characteristics

The analysis included 11 studies comprising 8 randomized controlled trials (RCTs) and 3 non-randomized, matched cohort studies (NRCTs), conducted across Europe, North America, and Saudi Arabia. Sample sizes ranged from 40 to 5,552 patients, with intervention groups receiving ERAH and control groups undergoing ORAH. The majority of participants were male (64–93%), with mean ages ranging from 55.7 to 69.7 years. Left ventricular ejection fraction (LVEF) varied across studies, with most reporting preserved function, though some studies did not provide LVEF data. Comorbidities were common, including hypertension (56–95%), diabetes mellitus (15–72%), peripheral artery occlusive disease (0–41%), and prior myocardial infarction (6.7–51%). Notably, the Burns [19] and Kiaii [23] studies share the same trial registration number and baseline characteristics, differing only in study setting, follow-up duration, and reported outcomes. Follow-up periods ranged from in-hospital assessment to 5 years, reflecting both short- and long-term outcomes across studies. Detailed baseline characteristics are summarised in Tables 1 and 2.

Table 1.

Characteristics of the Included studies

Study ID	Type of study	Country	Sample size			Regimen		Male Percentage %		Study duration	Follow-up
			Intervention	Control	Total	Intervention	Control	Intervention	Control
Bisleri 2016 [22]	NRCT, matching.	Italy, Poland	82	82	164	ERAH	ORAH	79.2	71.9	January 2005 – January 2014	5 years
Burns 2015 [19]	RCT	Canada	60	59	119	ERAH	ORAH	93.2	90	April 2005 – January 2007	> 5 years (mean ≈ 79 months)
Carrranza 2025 [10]	RCT	Denmark	151	149	300	ERAH	ORAH	88.7	88.6	May 2013 – October 2018	Primary follow-up: 3 months, Additional follow-up: 1 year
Grus 2011 [18]	RCT	Czech Republic	20	20	40	ERAH	ORAH	90	95	January 2005 – December 2007	1 month postoperative
Kiaii 2017 [22]	RCT	Canada	60	59	119	ERAH	ORAH	93.2	90	September 2006 – October 2009	6–8 weeks (clinical outcomes) + 6-month angiographic assessment
Navia 2011 [19]	NRCT, matching.	USA	39	117	156	ERAH	ORAH	90	95	January 2001 – July 2004	During hospitalization until discharge
Nowicki 2011 [21]	RCT	Poland	100	100	200	ERAH	ORAH	88	91	Jan 2004 – Dec 2007	3 years
Razzavi 2025 [9]	NRCT, matching.	US	2776	2776	5552	ERAH	ORAH	82.1	81	October 2015 – December 2022.	5 years (Mean follow-up: 3.18 yrs)
Rudez 2007 [17]	RCT	Croatia	25	25	50	ERAH	ORAH	64	72	October 2002 - October 2004	37 ± 7 months (approx. 3 yrs)
Shapira 2007 [16]	RCT	US	18	36	54	ERAH	ORAH (Cautery) + ORAH (Harmonic shears)	77.8	83.3	NA	Clinical follow-up during hospital stay.
Tamim 2020 [8]	RCT	Saudia Arabia	25	25	50	ERAH	ORAH	88	80	2016–2018	1 year

ERAH Endoscopic Radial Artery Harvest, ORAH Open Radial Artery Harvest, NA Not Available

Table 2.

Patient characteristics of the included studies

Study ID	Age (Years) Mean (SD)		LVEF (%) Mean (SD)		HTN (%)		DM (%)		PAOD (%)		Prior MI (%)
	ERAH	ORAH	ERAH	ORAH	ERAH	ORAH	ERAH	ORAH	ERAH	ORAH	ERAH	ORAH
Bisleri 2016 [22]	65.12 ± 11.29	66.5 ± 7.3	NA	NA	73.1	67.9	23.1	34.6	26.8	34.6	40.2	44.4
Burns 2015/ Kiaii 2017 [19, 23]	57.8 ± 6.8	57.9 ± 7.9	NA	NA	NA	NA	25	20.3	0	3.4	6.7	30.5
Carrranza 2025 [10]	63.17 ± 8.52	64.33 ± 10.37	NA	NA	68.2	69.1	15.9	17.4	NA	NA	25.8	23.5
Grus 2011 [18]	55.7 ± 6.8	53.3 ± 4.6	NA	NA	60	65	55	60	NA	NA	NA	NA
Navia 2011 [20]	60 ± 9.9	62 ± 9.1	50 ± 13	47 ± 13	77	79	18	19	41	43	51	50
Nowicki 2011 [21]	55.7 (NA)	59.7 (NA)	NA	NA	NA	NA	20	18	10	12	NA	NA
Razzavi 2025 [9]	69.67 ± 5.12	69.67 ± 5.2	NA	NA	95	94.4	48	48.2	27.2	28	NA	NA
Rudez 2007 [7]	60.5 ± 9.2	61.2 ± 9.8	NA	NA	56	60	32	24	NA	NA	NA	NA
Shapira 2007 [16]	60 ± 10	ORAH (Cautery): 58 ± 12; ORAH (Harmonic shears): 62 ± 12	53 ± 13	ORAH (Cautery): 51 ± 14; ORAH (Harmonic shears): 54 ± 11	72	ORAH (Cautery): 83; ORAH (Harmonic shears): 78	44	ORAH (Cautery): 61; ORAH (Harmonic shears): 22	22	ORAH (Cautery): 11; ORAH (Harmonic shears): 22	NA	NA
Tamim 2020 [8]	55.7 ± 9.1	56.8 ± 9.9	45.5 ± 7.5	48.4 ± 10.2	76	80	72	48	4	0	NA	NA

LVEF Left Ventricular Ejection Fraction, HTN Hypertension, DM Diabetes Mellitus, PAOD Peripheral Artery Occlusion Disease, MI Myocardial Infarction, ERAH Endoscopic Radial Artery Harvest, ORAH Open Radial Artery Harvest, NA Not Available

Risk of bias

Risk of bias was assessed for all included studies. Among the eight RCT reports included in the review, Burns et al. [19] and Kiaii et al. [23] originated from the same randomized trial and were therefore assessed as a single study using the Cochrane Risk of Bias 2 (RoB 2) tool. Consequently, seven unique RCTs were evaluated using the Cochrane Risk of Bias 2 (RoB 2) tool, two were judged to have a low risk of bias, four had some concerns primarily related to domains 2 (Deviation from intended intervention), 4 (Measurement of the outcome), and 5 (Selection of the reported result), and one was rated as high risk due to issues in domains 1 (Randomization process) and 5 (Selection of the reported result). Of the three observational studies, all were considered low risk, each achieving 8 stars on the Newcastle-Ottawa Scale. The full evaluations for each RCT are presented in Supplementary Figs. 1 and 2, while NOS ratings are provided in Supplementary Table 2.

GRADE assessment

The GRADE assessment of our results showed variable certainty of evidence across outcomes, ranging from high to very low. Freedom from MACCE was supported by high-quality evidence, reflecting consistent and precise estimates. Most key clinical outcomes; including 30-day and long-term mortality, myocardial infarction, stroke, patency rates, and wound-related complications; were graded as moderate to low certainty, mainly due to imprecision from wide confidence intervals and limited event numbers. Peri-operative outcomes such as cardiopulmonary bypass time, cross-clamp time, harvest time, and length of hospital stay were generally moderate quality in RCTs but low to very low in matched studies because of inconsistency, small sample sizes, or heterogeneity.

Neurological complications, pain-related outcomes, and the number of participants experiencing pain were downgraded to low certainty due to small event numbers and inconsistency. Rare outcomes including renal failure, septicemia, and hand ischemia could not be reliably assessed due to insufficient data. Overall, the most frequent reason for downgrading was imprecision, with additional downgrading for inconsistency and small event numbers in selected outcomes. Detailed GRADE assessment is provided in the Supplementary Table 3.

Meta-analysis of primary outcomes

Wound complications

Ten studies including 6,685 participants (3,296 intervention vs. 3,389 control) were analyzed. Overall, the intervention significantly reduced wound complications (RR = 0.61; 95% CI: 0.39 to 0.96; p = 0.03), with low-to-moderate heterogeneity (I² = 38%).

Subgroup analysis by study design showed no significant difference in RCTs (RR = 0.49; 95% CI: 0.18 to 1.38; p = 0.18; I² = 37%) or observational studies (RR = 0.59; 95% CI: 0.29 to 1.20; p = 0.15; I² = 57%), as illustrated in Fig. 2. Similarly, subgroup analysis by publication year showed no statistically significant difference in studies published before 2020 (RR = 0.37; 95% CI: 0.13 to 1.07; p = 0.07; I² = 36%) or in those published in/after 2020 (RR = 0.81; 95% CI: 0.64 to 1.01; p = 0.06; I² = 0%) (Supplementary Fig. 19).

Fig. 2.

Forest plot of wound complications

Wound infection rate

Nine studies comparing endoscopic versus open radial artery harvest included a total of 1,133 patients (520 endoscopic vs. 613 open). Overall, endoscopic harvest was associated with a significantly lower wound infection rate (RR = 0.57; 95% CI: 0.35 to 0.93; p = 0.03), with no heterogeneity observed (I² = 0%).

Subgroup analysis by study design showed no significant difference in RCTs (RR = 0.61; 95% CI: 0.36 to 1.03; p = 0.07; I² = 0%) or observational studies (RR = 0.30; 95% CI: 0.04 to 2.19; p = 0.24; I² = 41%) (Fig. 3). However, subgroup analysis by publication year demonstrated a significant reduction in wound infection among studies published before 2020 (RR = 0.28; 95% CI: 0.11 to 0.76; p = 0.01; I² = 0%), whereas studies published in or after 2020 showed no significant difference between groups (RR = 0.72; 95% CI: 0.41 to 1.26; p = 0.25; I² = 0%) (Supplementary Fig. 20).

Fig. 3.

Forest plot of wound infection rate

Patency rate

Four studies assessed patency rates. Overall, there was no significant difference between endoscopic and open radial artery harvest (RR = 1.01; 95% CI: 0.90 to 1.14; p = 0.23), with no heterogeneity (I² = 0%) (Fig. 4).

Fig. 4.

Forest plot of graft patency rate

Subgroup analysis by study design wasn’t feasible as no included observational studies reported this outcome. Similarly, stratification by publication year showed no significant difference in studies published before 2020 (RR = 0.98; 95% CI: 0.63 to 1.51; p = 0.91; I² = 0%) or in those published in or after 2020 (RR = 1.02; 95% CI: 0.90 to 1.14; p = 0.79; I² = 0%) (Supplementary Fig. 21).

Neurological complications

Seven studies including 872 patients (400 endoscopic vs. 472 open) reported neurological complications following radial artery harvest. Overall, there was no significant difference between groups (RR = 0.66; 95% CI: 0.35 to 1.24; p = 0.19), with substantial heterogeneity (I² = 73%) (Fig. 5). After sensitivity analysis excluding one outlier study (Tamim et al. [8]), the endoscopic group showed a significant reduction in neurological complications (RR = 0.44; 95% CI: 0.34 to 0.57; p < 0.00001; I² = 0%) (Supplementary Fig. 3).

Fig. 5.

Forest plot of neurological complications

In subgroup analysis by study design, RCTs showed no significant difference (RR = 0.75; 95% CI: 0.33 to 1.69; p = 0.48; I² = 82%), whereas observational studies demonstrated a significant benefit for endoscopic harvest (RR = 0.42; 95% CI: 0.20 to 0.91; p = 0.03; I² = 0%), shown in Fig. 5. When stratified by publication year, a significant benefit of endoscopic harvest was observed in the pre-2020 subgroup (RR = 0.53; 95% CI: 0.36 to 0.77; p = 0.0008; I² = 0%), but not in studies from 2020 onward (RR = 1.36; 95% CI: 0.10 to 18.70; p = 0.82; I² = 95%) (Supplementary Fig. 22).

Meta-analysis of secondary outcomes

Thirty-day mortality

Eight studies including 6,185 patients (3,045 endoscopic vs. 3,140 open) evaluated 30-day mortality. Overall, there was no significant difference between endoscopic and open radial artery harvest (RR = 1.22; 95% CI: 0.78 to 1.92; p = 0.38), with no observed heterogeneity (I² = 0%).

In subgroup analysis by study design, RCTs showed no effect (RR = 0.98; 95% CI: 0.06 to 15.36; p = 0.99), and observational studies also found no significant difference (RR = 1.23; 95% CI: 0.78 to 1.94; p = 0.38; I² = 0%), illustrated in Supplementary Fig. 5. This finding remained unchanged after stratification by publication year, with no significant differences observed in studies published before 2020 (RR = 0.78; 95% CI: 0.10 to 5.94; p = 0.81; I² = 0%) or in those published in or after 2020 (RR = 1.25; 95% CI: 0.79 to 1.98; p = 0.34) (Supplementary Fig. 23).

Long-term mortality

Five studies including 6,185 patients (3,094 endoscopic vs. 3,091 open) evaluated long-term mortality. Overall, there was no significant difference between endoscopic and open radial artery harvest (RR = 0.93; 95% CI: 0.82 to 1.06; p = 0.27), with no heterogeneity observed (I² = 0%).

Subgroup analysis by study design showed no significant effect in RCTs (RR = 0.76; 95% CI: 0.21 to 2.72; p = 0.67; I² = 0%) or observational studies (RR = 0.93; 95% CI: 0.82 to 1.06; p = 0.29; I² = 0%) (Supplementary Fig. 6). Comparable findings were observed after stratification by publication year, with no significant differences in studies published before 2020 (RR = 0.62; 95% CI: 0.21 to 1.84; p = 0.39; I² = 0%) or in those published in or after 2020 (RR = 0.94; 95% CI: 0.82 to 1.06; p = 0.32; I² = 0%) (Supplementary Fig. 24).

Freedom from Major Adverse Cardiac and Cerebrovascular Events (MACCE)

Freedom from MACCE was reported in two observational studies including 5,716 patients (2,858 endoscopic vs. 2,858 open). Overall, there was no significant difference between endoscopic and open radial artery harvest (RR = 1.00; 95% CI: 0.98 to 1.03; p = 0.87), with no heterogeneity (I² = 0%) (Supplementary Fig. 7).

Subgroup analysis by study design could not be performed because only observational studies reported this outcome. Stratification by publication year likewise revealed no appreciable difference, with the pre-2020 study reporting an RR of 0.99 (95% CI: 0.91 to 1.07; p = 0.75) and the post-2020 study an RR of 1.00 (95% CI: 0.98 to 1.03; p = 0.78) (Supplementary Fig. 25).

Length of harvested artery (cm)

Four studies including 330 patients (165 endoscopic vs. 165 open) reported the length of harvested artery (cm). Overall, there was no significant difference between groups (MD = − 0.39; 95% CI: −1.54 to 0.76; p = 0.51), with considerable heterogeneity (I² = 88%) (Supplementary Fig. 8).

After sensitivity analysis removing Nowicki et al. [21], endoscopic harvest was associated with a significantly shorter artery length (MD = − 0.99; 95% CI: −1.48 to − 0.51; p < 0.0001), and heterogeneity was eliminated (I² = 0%) (Supplementary Fig. 4). Subgroup analysis by study design was not feasible, as this outcome was reported exclusively by RCTs. When stratified by publication year, no significant difference was observed in studies published before 2020 (MD = − 0.39; 95% CI: −1.75 to 0.97; p = 0.58; I² = 92%) or in the study published in or after 2020 (MD = − 0.40; 95% CI: −2.09 to 1.29; p = 0.64) (Supplementary Fig. 26).

Number of patients experiencing pain

Three studies including 246 participants (84 endoscopic vs. 162 open) reported the number of patients experiencing pain. Overall, endoscopic radial artery harvest was associated with a significantly lower incidence of pain (RR = 0.44; 95% CI: 0.26 to 0.74; p = 0.002), with no heterogeneity (I² = 0%).

Subgroup analysis demonstrated a significant reduction in pain in RCTs (RR = 0.19; 95% CI: 0.04 to 0.80; p = 0.02; I² = 0%), and a similar significant benefit was observed in observational studies (RR = 0.50; 95% CI: 0.28 to 0.88; p = 0.02), shown in Supplementary Fig. 9.

Meta-analysis of safety outcomes

Postoperative pain (VAS)

Two studies (one RCT and one observational study) including 283 participants (142 endoscopic vs. 141 open) assessed postoperative pain using the VAS score. Overall, there was no significant difference between groups (MD = − 1.16; 95% CI: −2.85 to 0.54; p = 0.33).

In subgroup analysis, the RCT showed no significant difference (MD = − 0.27; 95% CI: −0.82 to 0.28), while the observational study demonstrated a significant reduction in pain with endoscopic harvest (MD = − 2.00; 95% CI: −2.12 to − 1.88; I² = 0%) (Supplementary Fig. 10).

Hand ischemia

Three studies including 268 patients (125 endoscopic vs. 143 open) reported hand ischemia. No events of hand ischemia were observed in either group across all included studies, precluding estimation of a pooled effect size (Supplementary Fig. 11).

Septicemia

Two studies including 275 patients (99 endoscopic vs. 176 open) assessed septicemia following radial artery harvest. The overall analysis showed no significant difference between the groups (RR = 1.15; 95% CI: 0.13 to 10.10; p = 0.90), with minimal heterogeneity (I² = 8%).

By study design, the RCT reported no significant effect (RR = 0.33; 95% CI: 0.01 to 7.89; p = 0.49), and the observational study also found no significant difference (RR = 3.00; 95% CI: 0.19 to 46.83; p = 0.43), illustrated in Supplementary Fig. 12.

Myocardial Infarction (MI)

Four studies including 513 patients (249 endoscopic vs. 264 open) reported myocardial infarction (MI) after radial artery harvest. Overall, there was no significant difference between endoscopic and open groups (RR = 0.40; 95% CI: 0.08–2.40; p = 0.27), with no heterogeneity observed (I² = 0%) (Supplementary Fig. 13).

Subgroup analysis by study design was not applicable, as only RCTs reported this outcome. Stratification by publication year likewise showed no significant difference, with an RR of 0.33 (95% CI: 0.04 to 3.09; p = 0.33; I² = 0%) in studies published before 2020 and 0.49 (95% CI: 0.05 to 5.38; p = 0.56) in studies published in or after 2020 (Supplementary Fig. 27).

Renal failure

Two studies including 275 patients (99 endoscopic vs. 176 open) reported renal failure. Overall, there was no significant difference between groups (RR = 0.42; 95% CI: 0.02–7.98; p = 0.56) (Supplementary Fig. 14). Subgroup analysis was limited, as no events occurred in the RCTs.

Meta-analysis of peri-operative outcomes

Cardiopulmonary Bypass (CPB) time

Four studies including 489 patients (206 endoscopic vs. 283 open) reported CPB time. Overall, CPB time was significantly shorter in the endoscopic group (MD = − 4.22 min; 95% CI: −6.46 to − 1.98; p = 0.0002), with no heterogeneity (I² = 0%).

In subgroup analysis by study design, RCTs showed no significant difference (MD = − 1.53 min; 95% CI: −11.55 to 8.48; p = 0.76; I² = 17%), whereas observational studies demonstrated a significant reduction in CPB time with endoscopic harvest (MD = − 4.38 min; 95% CI: −6.70 to − 2.06; p = 0.0002; I² = 0%) (Supplementary Fig. 15). Publication-year stratification revealed a significant reduction in CPB time in studies published before 2020 (MD = − 4.41 min; 95% CI: −6.67 to − 2.15; p = 0.0001; I² = 0%), but not in those published in or after 2020 (MD = 6.00 min; 95% CI: −10.67 to 22.67; p = 0.48) (Supplementary Fig. 28).

Aortic cross-clamp time

Four studies including 489 patients (206 endoscopic vs. 283 open) reported aortic cross-clamp time. Overall, there was no significant difference between groups (MD = − 0.59 min; 95% CI: −3.03 to 1.86; p = 0.64; I² = 0%).

Subgroup analysis by study design showed no significant difference in RCTs (MD = 0.12 min; 95% CI: −5.76 to 6.01; p = 0.97; I² = 0%) or in observational studies (MD = − 0.73 min; 95% CI: −3.43 to 1.96; p = 0.59; I² = 0%) (Supplementary Fig. 16). No meaningful variation was observed after stratification by publication year, as both pre-2020 (MD = − 0.73 min; 95% CI: −3.43 to 1.96; p = 0.59; I² = 0%) and those published in or after 2020 (MD = 4.00 min; 95% CI: −6.84 to 14.84; p = 0.47) showed no significant difference (Supplementary Fig. 29).

Radial artery harvest time

Six studies including 627 patients (305 endoscopic vs. 322 open) evaluated radial artery harvest time. Overall, there was no significant difference between the endoscopic and open groups (MD = 8.77 min; 95% CI: −6.02 to 23.56; p = 0.25), with substantial heterogeneity (I² = 99%).

Subgroup analysis by study design revealed a non-significant increase in harvest time in RCTs (MD = 11.24 min; 95% CI: −13.05 to 35.54; p = 0.36; I² = 99%), while observational studies showed a significant reduction in harvest time with the endoscopic technique (MD = − 2.70 min; 95% CI: −3.96 to − 1.44; p < 0.0001), as illustrated in Supplementary Fig. 17. This pattern remained unchanged after stratification by publication year, with neither pre-2020 (MD = 9.95 min; 95% CI: −7.23 to 27.14; p = 0.26; I² = 99%) nor those published in or after 2020 (MD = 3.00 min; 95% CI: −3.38 to 9.38; p = 0.36) showing a significant difference (Supplementary Fig. 30).

Length of hospital stay (days)

Length of hospital stay (LOS) was reported in two studies including 5,602 patients (2,801 endoscopic vs. 2,801 open). Overall, endoscopic radial artery harvest was associated with a small but significant reduction in LOS (MD = − 0.33 days; 95% CI: −0.48 to − 0.17; p < 0.0001), with no heterogeneity (I² = 0%).

Subgroup analysis showed no difference in RCTs (MD = 0.00 days; 95% CI: −1.01 to 1.01; p = 1.00), whereas observational studies demonstrated a significant reduction in LOS with the endoscopic approach (MD = − 0.33 days; 95% CI: −0.49 to − 0.18; p < 0.0001) (Supplementary Fig. 18).

Discussion

This updated systematic review and meta-analysis evaluated the safety and efficacy of endoscopic radial artery harvesting (ERAH) versus open radial artery harvesting (ORAH) in patients undergoing CABG. Eleven studies, including eight RCTs and three propensity-matched observational studies involving more than 6,600 patients, were included. Overall, ERAH was associated with lower rates of wound complications, wound infection, and postoperative pain, while demonstrating comparable graft patency, perioperative outcomes, and short- and long-term mortality. No significant differences were observed in major adverse cardiac and cerebrovascular events (MACCE), myocardial infarction, or other postoperative complications. These findings suggest that ERAH provides comparable clinical outcomes to ORAH, with potential donor-site benefits that should be interpreted cautiously in light of the randomized evidence.

The radial artery has emerged as an important conduit for CABG due to its favorable biological characteristics, including a thicker medial layer, greater resistance to atherosclerosis, and superior long-term patency compared with saphenous vein grafts [4]. Multiple randomized trials and meta-analyses have demonstrated its superiority over saphenous vein grafts in terms of long-term patency and major adverse cardiac events, particularly in vessels with high-grade stenosis [24]. Despite these advantages, the conventional open radial artery harvesting technique involves a long forearm incision that may predispose patients to wound complications, postoperative pain, and sensory disturbances. These donor-site complications have historically been considered potential barriers to the broader adoption of radial artery grafting in clinical practice. Endoscopic radial artery harvesting was introduced as a minimally invasive technique to reduce surgical trauma and improve cosmetic outcomes while preserving conduit integrity [25, 26]. However, early skepticism existed regarding potential endothelial injury or conduit damage during endoscopic dissection, raising concerns about graft durability and long-term patency. The findings of the present meta-analysis contribute additional evidence addressing these concerns.

One of the most important findings of our analysis was the significant reduction in wound complications (RR = 0.61) and wound infection rate (RR = 0.57) associated with ERAH. The pooled analysis demonstrated a moderate risk reduction favoring the endoscopic technique. These findings are broadly consistent with prior meta-analyses. Huang et al. reported significantly lower wound complication rates (RR = 0.33, p = 0.0005) among patients undergoing endoscopic harvesting compared with the open technique [6]. Similarly, Cao et al. demonstrated reduced wound infection and hematoma formation with ERAH [7]. Rahouma et al., in a meta-analysis of randomized and propensity-matched studies, also confirmed a significant reduction in wound complications associated with the endoscopic approach [5]. The somewhat attenuated effect estimate observed in the present analysis for wound complications (RR = 0.61 vs. RR = 0.36) may partly reflect the more conservative study selection criteria, as the exclusion of non-matched observational studies reduces the potential influence of selection bias, where endoscopic harvesting may have been preferentially performed in lower-risk patients. Notably, this benefit was not preserved in the RCT-only subgroup, suggesting that the overall effect may be influenced by observational data, unlike previous meta-analyses [5–7]. Subgroup analysis by publication year showed attenuation of the reduction in wound complications over time, although the findings continued to favor ERAH. This trend may reflect improvements in open harvesting techniques and wound care protocols in contemporary surgical practice, potentially narrowing the difference between the two approaches. The mechanistic explanation for this benefit is likely multifactorial. The open technique requires a full-length forearm incision and extensive soft-tissue dissection, which may increase the risk of tissue trauma, infection, and delayed healing. In contrast, ERAH utilizes a small portal incision and endoscopic dissection with minimal disruption of surrounding tissue planes. This small (approximately 2–3 cm) incision substantially reduces the surface area at risk for contamination, devitalized tissue, and wound dehiscence [27]. Reduced tissue trauma and improved preservation of skin vascularity may therefore contribute to the lower wound complication rates observed with the endoscopic technique. Regarding wound infection, publication-year subgroup analysis suggested that the benefit of ERAH was confined to earlier studies (RR = 0.28), with no significant difference observed in more contemporary studies. This temporal pattern may reflect advances in perioperative infection control, antimicrobial prophylaxis, and wound closure techniques, which have likely reduced baseline infection rates and narrowed the relative advantage of the endoscopic approach.

Postoperative pain is another clinically meaningful outcome that favored ERAH in the present study. Our analysis demonstrated a significant reduction in the proportion of patients experiencing postoperative forearm pain with the endoscopic technique (RR = 0.44) with no heterogeneity. These findings are consistent with previous randomized trials and observational studies of patient-reported outcomes following radial artery harvesting. Kiaii et al. reported significantly lower postoperative pain and improved patient satisfaction with ERAH compared with ORAH [23]. Similarly, Bisleri and colleagues observed reduced neuralgia and improved cosmetic satisfaction in patients undergoing endoscopic harvesting [26]. The VAS-based pain assessment, reported in two studies with a combined 283 patients, did not achieve statistical significance in the pooled analysis (MD = − 1.16), although the observational study component showed a larger significant reduction (MD = − 2.00). The discordance between these two pain metrics may reflect heterogeneity in pain assessment methodologies and the relatively modest sample sizes of studies reporting VAS outcomes. The biological plausibility for less pain with ERAH is supported by the extensive skin mobilization, retraction, and subcutaneous dissection required with the open approach, which may predispose to lateral antebrachial cutaneous nerve injury, scar-related hypersensitivity, and prolonged wound healing [28].

Neurological complications following radial artery harvesting, including numbness, paresthesia, and sensory deficits, represented a more heterogeneous outcome in this meta-analysis. In the primary analysis, ERAH did not demonstrate a statistically significant reduction in neurological complications (RR = 0.66), with substantial heterogeneity (I² = 73%); however, sensitivity analysis revealed a significant benefit once an outlier study was removed. Previous studies have also reported variable results, partly due to differences in the definition and assessment of neurological complications. Bleiziffer et al. observed higher rates of superficial radial nerve irritation following endoscopic harvesting, potentially related to the confined endoscopic working space [28]. Conversely, other investigations have suggested that open harvesting may increase the risk of injury to the lateral antebrachial cutaneous nerve due to extensive skin retraction. Huang et al. reported a significant reduction in neurological complications with ERAH in their meta-analysis, suggesting that the minimally invasive technique may reduce clinically relevant nerve injury [6]. Publication-year subgroup analysis suggested that the neurological benefit of ERAH was evident only in earlier studies, whereas more contemporary studies showed no clear advantage. This may reflect improvements in surgical technique, evolving outcome definitions, or differences in patient selection, although the limited number of recent studies warrants cautious interpretation. Overall, the available evidence suggests a possible advantage of ERAH in donor-site neurological morbidity, although the findings remain somewhat inconsistent across studies.

Preservation of graft patency is the most critical determinant of long-term success following CABG. Our analysis demonstrated no significant difference in radial artery graft patency between ERAH and ORAH (RR = 1.01), indicating that the endoscopic technique does not appear to compromise conduit integrity. These findings are consistent with previous randomized trials and meta-analyses evaluating graft durability [5, 6]. Wu et al. conducted a meta-analysis focusing specifically on graft patency and concluded that ERAH does not compromise conduit performance [29]. A prospective RCT by Tamim et al. [8] involving 50 patients reported 90% 1-year angiographic patency with no intergroup difference, further supporting the comparability of the two techniques when performed at experienced centres [8]. This preservation of graft patency is biologically plausible, as endothelial integrity can be maintained during endoscopic dissection when appropriate surgical technique is employed. Modern endoscopic harvesting systems provide precise visualization and controlled vessel dissection, helping minimize mechanical trauma while preserving conduit function.The absence of temporal differences in subgroup analyses further supports the consistency of conduit quality across earlier and contemporary studies.

Regarding conduit length, our meta-analysis showed that ERAH produced slightly shorter radial artery segments than ORAH (MD = − 0.99 cm), although the clinical impact is likely minimal, as the artery remains adequate for grafting. This complements prior reports [5], which cited only a single study with a minor length difference, and suggests that technical constraints of the endoscopic tunnel may reduce harvested length by about 1 cm without compromising graft utility. Publication-year subgroup analysis did not demonstrate meaningful temporal differences, suggesting that this modest reduction has remained consistent over time.

Another important observation from the present analysis is the lack of significant differences in major clinical outcomes, including 30-day mortality, long-term mortality, freedom from MACCE, myocardial infarction, renal failure, septicemia, and hand ischemia. While some of these outcomes were assessed for the first time in this study, others were consistent with previous systematic reviews evaluating harvesting techniques. Cao et al. and Huang et al. also reported no significant differences in survival outcomes between ERAH and ORAH [6, 7]. These findings suggest that the minimally invasive harvesting technique is unlikely to introduce additional perioperative risk. Publication-year subgroup analyses also showed no evidence that short- or long-term mortality differed between earlier and more recent studies, supporting the consistent safety profile of ERAH across study eras.

Among perioperative outcomes, ERAH was associated with a modest reduction in cardiopulmonary bypass time, although this effect was primarily driven by observational studies (MD = − 4.22 min). This reduction was observed only in earlier studies, whereas more recent studies showed no significant difference, suggesting that improvements in operative workflow may have reduced the procedural advantage of ERAH over time. Aortic cross-clamp time and radial artery harvest time were not significantly different between techniques. Variability in harvest time likely reflects the learning curve associated with ERAH, as surgeons typically require approximately 20–40 cases to achieve efficiency comparable to open harvesting [25]. Hospital length of stay was significantly shorter with ERAH (MD = − 0.33 days; p < 0.0001), although this finding was largely influenced by the observational study component and should therefore be interpreted cautiously.

Implications for guidelines

The findings of this meta-analysis carry direct relevance in the context of contemporary revascularization guidelines, which have increasingly elevated the role of the radial artery as a surgical conduit. The 2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization confers a Class I recommendation for the use of the radial artery over the saphenous vein as a conduit to bypass the second most critical coronary target vessel with significant stenosis [30]. Similarly, the 2018 ESC/EACTS Guidelines on Myocardial Revascularization recommended the use of radial artery grafts over saphenous vein in patients with high-grade coronary stenosis, reinforcing its role as a preferred secondary conduit in CABG [31]. Accordingly, the optimal harvesting technique for the radial artery, open versus endoscopic, becomes an increasingly important consideration. A key concern historically raised against ERAH was the possibility of endothelial injury during endoscopic dissection compromising conduit quality; the present meta-analysis, demonstrating comparable graft patency (RR = 1.01) and long-term clinical outcomes between the two techniques, provides reassurance that ERAH can be performed without compromising conduit integrity. Notably, the same 2018 ESC/EACTS guidelines included a Class IIa recommendation that the no-touch technique be employed when saphenous vein harvesting is performed open [31], highlighting the importance of minimizing conduit trauma where technically feasible and drawing parallels with the endoscopic approach to radial artery harvesting. The present evidence base suggests analogous considerations should apply to radial artery harvesting, with ERAH representing a technically viable and clinically safe approach. Importantly, however, the lack of a consistently demonstrable wound-complication benefit when the analysis is restricted to randomized evidence, and the temporal attenuation of several outcome benefits in post-2020 studies, suggests that future guideline recommendations regarding ERAH specifically should await higher-quality RCT data before a formal technique preference can be endorsed.

Strengths

This meta-analysis has several important strengths. First, the study design was restricted to randomized controlled trials and propensity-matched studies, thereby minimizing selection bias compared with previous reviews that included unmatched observational cohorts. Second, the analysis included a large pooled sample size exceeding 6,000 patients, providing greater statistical power for evaluating clinically relevant outcomes. Third, rigorous methodological assessment was performed using established tools for risk of bias evaluation and certainty of evidence was assessed using the GRADE framework for each outcome.

Limitations

Despite these strengths, several limitations should be acknowledged. The number of randomized trials included in the analysis was relatively limited, and some outcomes were associated with small event numbers, resulting in wide confidence intervals. Additionally, definitions of certain outcomes, particularly neurological complications and wound complications, varied between studies, which may have contributed to heterogeneity. Differences in surgical expertise and institutional experience may also influence outcomes, as ERAH is known to involve a procedural learning curve. Additionally, publication bias could not be formally assessed for most outcomes due to the limited number of included studies, which precludes reliable evaluation of funnel plot asymmetry. Subgroup analyses by publication year were limited by the small number of studies in each temporal stratum, reducing statistical power and increasing the instability of effect estimates, particularly for outcomes with few events. Only three included studies were published in 2020 or later, and only one had a large sample size, limiting the representativeness and reliability of the post-2020 subgroup. Additionally, three included studies lacked follow-up beyond one year, further restricting the assessment of long-term conduit durability and the evolution of ERAH techniques over time. For the majority of secondary and safety outcomes, only a single post-2020 study contributed data, precluding meaningful documentation of trends over time for these endpoints. Taken together, these limitations underscore the exploratory nature of the publication-year subgroup analyses, and the temporal comparisons presented should be interpreted with caution rather than as definitive evidence of technical progress or regression.

Conclusion

ERAH shows comparable graft patency and major clinical outcomes to ORAH in CABG. Although prior meta-analyses reported reduced donor-site morbidity, this benefit is not consistently supported when restricted to randomized evidence in the present updated analysis, suggesting uncertainty regarding its true magnitude. Subgroup analysis by publication year further indicates that several outcome benefits previously attributed to ERAH, including wound infection and neurological complications, appear attenuated or absent in more contemporary studies, raising the possibility that advances in open harvesting techniques and perioperative care may have narrowed the gap between the two approaches. However, these temporal observations should be interpreted cautiously given that only three studies from 2020 onward were included, only one of which had a large sample size, and most outcomes in the post-2020 subgroup were informed by a single study with limited follow-up. As such, the present data do not permit definitive conclusions regarding technical progress over time. ERAH therefore appears safe but not definitively superior. Future well-powered multicentre RCTs with standardized outcome definitions, formal nerve conduction assessments, and long-term angiographic follow-up will be important to further clarify neurological outcomes and long-term conduit durability.

Abbreviations

CABG

Coronary Artery Bypass Grafting

CAD

Coronary Artery Disease

CI

Confidence Interval

CPB

Cardiopulmonary Bypass

DM

Diabetes Mellitus

ERAH

Endoscopic Radial Artery Harvesting

GRADE

Grading of Recommendations Assessment, Development and Evaluation

HTN

Hypertension

LVEF

Left Ventricular Ejection Fraction

MACCE

Major Adverse Cardiac and Cerebrovascular Events

MD

Mean Difference

MI

Myocardial Infarction

NOS

Newcastle–Ottawa Scale

ORAH

Open Radial Artery Harvesting

PAOD

Peripheral Arterial Occlusive Disease

PRISMA

Preferred Reporting Items for Systematic Reviews and Meta–Analyses

RA

Radial Artery

RCT

Randomized Controlled Trial

ROB 2

Revised Cochrane Risk of Bias Tool 2

RR

Risk Ratio

SD

Standard Deviation

VAS

Visual Analog Scale

Authors’ contributions

Authors' Contributions T.I.Q. contributed to screening, data extraction, and analysis. A.A.M. contributed to risk of bias assessment, screening, data extraction, manuscript compilation, and journal selection. M.K. participated in data extraction, analysis, and screening. M.Ya. contributed to GRADE assessment and results writing. Y.A. wrote the discussion section. S.I. drafted the introduction and abstract sections. M.U.G. assisted with data extraction and risk of bias assessment. A.K. contributed to manuscript revision, response to reviewers, and critical review of the revised manuscript. F.M. compiled the manuscript and performed referencing. A.S.K. wrote the methods section and contributed to screening. A.S. contributed to corresponding author responsibilities, manuscript review, and submission procedures. M.M.A. designed and prepared the graphical abstract. P.K. contributed to data extraction. M.A.A.R. contributed to screening and analysis. S.R. contributed to discussion writing. M.Ys. contributed to GRADE assessment and evidence synthesis. M.H.K. contributed to results writing. H.W.K. contributed to methods writing. A.B. contributed to quality assessment and search strategy formulation. Ha.W.K. contributed to introduction writing. B.W.K. conceptualized the study, supervised the project, and thoroughly reviewed the manuscript. All authors contributed to the revision of the manuscript, critically reviewed the final version, and approved the manuscript for publication.

Funding

The authors declare no potential conflicts of interest related to the research, authorship, and publication of this article, and report that no funding was received for this study.

Data availability

All data supporting the findings of this study are available within the paper and its Supplementary Information.

Declarations

Ethics approval and consent to participate

Ethical approval was not required for this systematic review and meta-analysis. Human Ethics and Consent to Participate declarations: not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.