Graft patency was assessed in selected studies by coronary angiography or computed tomography angiography at the time of discharge or postoperative follow-up. When both investigations were performed, data from coronary angiography were selected for analysis because it remains to be the standard investigation to assess graft patency. A graft was considered “patent” as defined by individual studies, including those grafts that were perfectly patent, grafts that were patent with minor irregularities, or grafts that did not demonstrate occlusion or stenosis.10,12,15 Two studies reported graft patency outcomes according to the number of grafts (88.7% vs 85.8%; RR, 1.04; 95% CI, 0.97–1.12; P = 0.24; I2 = 0%), and two studies reported the number of patients who had patent grafts at follow-up (75.9% vs 78.1%; RR, 1.00; 95% CI, 0.83-1.21; P = 0.97; I2 = 0%, Fig. 4). Neither measurements reached statistical significance comparing endoscopic versus open techniques.
In regard to perioperative morbidities, patients who underwent endoscopic radial artery harvesting had significantly lower incidences of wound infection (1.0% vs 4.0%; RR, 0.36; 95% CI, 0.16–0.82; P = 0.01; I2 = 0%; Fig. 5), hematoma formation (2.9% vs 4.0%; RR, 0.45; 95% CI, 0.26–0.77; P = 0.004; I2 = 43%; Fig. 6), and paresthesia (23.5% vs 30.9%; RR, 0.77; 95% CI, 0.61–0.99; P = 0.04; I2 = 42%; Fig. 7) when compared with patients who underwent the conventional open approach.
Since the introduction of antispasmodic medications and improvements in surgical techniques in the 1990s, there has been a growing interest in the use of the radial artery as a conduit for CABG. Although patients with less severe native coronary artery disease (<90% stenoses) have been shown to have worse patency outcomes,10,23 available evidence suggests that the radial artery is associated with superior angiographic outcomes at short-term and midterm follow-up compared with saphenous veins. Meta-analysis of randomized controlled trials have established higher incidences of complete patency as well as lower incidences of graft occlusion and graft failure after CABG using the radial artery.4,5 Nonetheless, concerns about the angiographic finding of the “string sign” persist, and patient selection in the randomized trials was strictly limited to severe (>70% stenoses) target vessel lesions.
Endoscopic harvesting of conduits attracted growing popularity since the first endoscopic saphenous vein harvest was performed in 1996.24 Encouraging data from institutional reports suggesting similar MACCE with improved perioperative morbidity outcomes through the endoscopic approach have resulted in the popularization of this technique during the past decade. Recent data from The Society of Thoracic Surgeons National Database reported that endoscopic harvesting was performed in up to 70% of CABG surgeries in the United States.25 However, a large retrospective analysis involving 3000 patients recently demonstrated that the endoscopic harvesting technique was associated with higher rates of vein graft failure at 12 to 18 months after surgery as well as higher incidences of mortality, myocardial infarction, or revascularization at 3 years.25
The results of the present study comparing endoscopic versus open techniques of harvesting the radial artery identified similar MACCE outcomes but superior morbidity outcomes for the minimally invasive approach. The incidences of mortality, myocardial infarction, and graft patency outcomes were similar between the two treatment groups, but patients who underwent endoscopic harvesting had significantly lower incidences of wound infection, hematoma formation, and paresthesia. Although the findings regarding MACCE outcomes are similar to previous individual reports, perioperative morbidities were consistently lower after endoscopic surgery in the present meta-analysis as compared with individual reports, possibly as a result of a larger number of patients analyzed. Our data suggest that patients who undergo endoscopic harvesting are less than half as likely to have hematoma formation and nearly a third as likely to have wound infection, when compared with the conventional open approach.
A number of limitations of the present meta-analysis should be acknowledged, and our results should be interpreted with caution. Firstly, none of the 12 selected studies included for analysis were randomized, and hence, these were subject to patient selection bias. Secondly, patient baseline characteristics, endoscopic harvesting techniques, and medication regimens varied among institutions. However, no statistically significant heterogeneity was identified from our analysis. Finally, the follow-up periods were relatively short or not specified, and outcomes such as graft patency were often measured only at the time of discharge. However, one study involving more than 200 patients who underwent angiography beyond 3 years demonstrated similar patency outcomes between the two surgical treatment groups.12 Overall, the results of the meta-analysis should be interpreted with caution because of the abovementioned limitations, and any superiority of the endoscopic approach should not be overstated because of the limited evidence.
In conclusion, existing evidence suggests that endoscopic harvesting of the radial artery is a safe procedure that can potentially offer superior perioperative outcomes related to wound infection, hematoma formation, and paresthesia, without clearly demonstrating any increased major adverse events such as mortality, myocardial infarction, and graft occlusion. However, future studies should aim to involve randomization with longer follow-up periods and a larger patient cohort to assess both angiographic and clinical outcomes to provide more robust evidence.
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This meta-analysis examined endoscopic versus conventional open radial harvesting for coronary artery bypass graft surgery. Twelve studies involving more than 3000 patients were examined. There were no significant differences in overall mortality, recurrent myocardial infarction, or graft patency between the two techniques. However, patients who underwent endoscopic harvesting were found to have a significantly lower incidence of wound infections, hematoma formation and paresthesias.
This meta-analysis suggests that the endoscopic approach has superior perioperative outcomes without compromising short-term results. However, there are weaknesses in this analysis. None of the studies that were examined were randomized, and hence, all may have been subjected to patient selection bias. Finally, the follow-up periods were relatively short, and only one of the studies looked at even medium-term outcomes. Keeping these limitations in mind, this study suggests that endoscopic harvesting of the radial artery is a safe procedure in the short-term and may offer superior perioperative outcomes in terms of wound complications. However, if there was a difference in long-term patency between these techniques, these advantages would be nullified. Future studies in this area are keenly anticipated.