Coronary artery bypass grafting remains one of the most commonly performed cardiac operations worldwide. However, despite the growing body of evidence, important questions remain regarding graft selection and, more specifically, the optimal harvesting technique. Current guidelines recommend prioritizing arterial grafts in patients with a long life expectancy. In this setting, the radial artery has shown excellent midterm and long-term results in terms of patency, morbidity, and mortality, both in comparison with venous grafts and with other arterial conduits.

Nevertheless, the evidence regarding radial artery harvesting technique remains limited, particularly with respect to randomized clinical trials. Although some observational studies and small trials suggest a possible benefit of the endoscopic technique in terms of local complications, the currently available data remain insufficient to support this approach conclusively.

It is within this context that the NEO trial (Neurological Complications in Endoscopic versus Open Radial Artery Harvest) was conducted, a superiority trial comparing both techniques. This study is part of a broader project that will evaluate different arterial graft configurations (mammario-radial and aorto-radial), although those results are not included in the present analysis.

After sample size calculation, 300 adult patients with isolated multivessel coronary artery disease scheduled for elective or subacute surgery were enrolled. Participants were randomized in a 1:1 ratio to endoscopic or open harvest, with stratification by age and sex. As is usual in this type of intervention, neither patients nor surgeons could be blinded. However, ancillary test evaluators, statisticians, and authors remained unaware of the specific assignment of each group.

The primary endpoint, hand function at 3 months, was assessed using the Hand Function Questionnaire (HFQ), a 9-item scale with a total score ranging from 5 to 49, with lower values indicating better function. The secondary endpoint included assessment of neurologic deficit by means of nerve conduction studies and clinical examination. Donor-limb complications and major adverse events related to cardiac surgery were also recorded.

The primary endpoint analysis was performed using a two-sided significance level of 5%, whereas secondary variables were described with 95% confidence intervals without adjustment for multiplicity.

Between May 2013 and October 2018, 4923 patients were screened, of whom 300 were ultimately randomized (151 to the endoscopic group and 149 to the open group). The analysis was performed according to the intention-to-treat principle, with only 4 patients lost to follow-up.

At 3 months, the mean HFQ score was 7.2 in the endoscopic group versus 7.74 in the open group, a statistically significant difference (p = .03). Regarding neurologic deficit, abnormalities on nerve conduction studies were more frequent in the open group (55% vs. 21.2%), as were pathologic findings on clinical examination (45.6% vs. 29.8%).

Complications in the donor limb were also more frequent with the open technique (17.4% vs. 12.6%). However, serious adverse events, such as reoperation for bleeding, need for repeat revascularization, or death, were more common in the endoscopic group (6% vs. 2.7%).

The authors conclude that endoscopic radial artery harvest is associated with a modest improvement in patient-reported function and with a lower incidence of neurologic deficit at 3 months. However, they acknowledge important limitations, including the absence of a clear threshold for clinically meaningful difference and the inherent challenges of blinding in surgical trials.

COMMENTARY:

As in many areas of cardiovascular surgery, and of medical practice more broadly, graft selection in coronary revascularization, together with harvesting technique and graft configuration, remains surrounded by controversy and supported by limited scientific evidence. The difficulty in identifying clinically meaningful differences probably reflects patient heterogeneity, the burden of comorbidities, variability in the presentation of coronary artery disease, and, not least, the technical and logistical constraints inherent to both surgeons and centers.

This Danish study tackles a question of clear clinical significance and does so with a methodological rigor consistent with the standards of the journal in which it appears. Even so, a critical reading requires going beyond the main manuscript and carefully reviewing both the supplementary material and the previously published protocol, where key elements can be found for an appropriate interpretation of the results and for answering many of the questions that arise while reading it.

What is striking is the very small magnitude of the difference in patient satisfaction with the donor limb between the 2 groups: less than 1 point on a scale of up to 49. The questionnaire used, developed by an Australian group led by Yan Zhu in 2017, has not been formally validated, unlike widely used instruments such as DASH in hand surgery. Although its authors proposed a value of 3 in certain items as a threshold for clinical relevance, that criterion lacks robust validation.

Review of the supplementary material is particularly revealing: virtually all questionnaire items cluster around values of 1, absence of symptoms, or 2, trivial symptoms, in both groups, that is, at the least severe end of the spectrum. Although no item-by-item statistical comparisons are presented, the differences that seem to underpin the overall result are concentrated in the questions addressing paresthesia and scar appearance. In both cases, the open-harvest group shows slightly higher scores, approaching a value of 2, yet always within the range of trivial symptoms and below the threshold considered clinically relevant.

These very small differences contrast with the results obtained using validated scales that were also included in the supplementary material. Thus, on the LANSS scale for pain and neuropathic symptoms, the endoscopic harvest group actually showed a slightly higher proportion of patients with significant symptoms (7.9% vs. 6% in the open group). Likewise, cosmetic scar assessment using the validated Stony Brook scale, widely used in plastic surgery, showed no relevant between-group differences (4.55 vs. 4.37 for endoscopic and open harvest, respectively).

And it is worth emphasizing that such important events as reoperation for bleeding, potentially related to less reliable vascular control of collateral branches, the need for repeat revascularization, or death were more frequent in the endoscopic group (6% vs. 2.7%). These events, although infrequent, undermine any attempt to justify reduced invasiveness in graft harvest for the 3.3% of patients in whom they occurred.

Taken together, the study by Carranza et al. demonstrates statistically significant differences in the HFQ. However, the fact that this was a nonvalidated tool and that the observed differences were of such limited magnitude raises serious doubts about their true clinical relevance. In this context, it is difficult to argue that these findings alone justify widespread adoption of a more complex and more costly technique.

Even so, given the methodological strength of the investigative group, it is reasonable to anticipate that future analyses, particularly those focused on composite arterial graft configurations, will provide more conclusive evidence and help illuminate a field that, for now, remains in partial shadow.

REFERENCE:

Carranza CL, Petersen JJ, Ballegaard M, Werner MU, Hasbak P, Kjaer A et al. Endoscopic or Open Radial Artery Harvest in Coronary Artery Bypass Surgery. NEJM Evid. 2026 Jan;5(1):EVIDoa2500199. doi: 10.1056/EVIDoa2500199.