5. From reduction to complete avoidance of aortic manipulations: anaortic OPCAB
Surgical strategies that rely on any type of manipulation of the aorta (including its major branches) or on the use of CPB may ultimately fail to meaningly improve the rate of perioperative neurologic injury in patients with severe aortic atherosclerosis. Anaortic OPCAB techniques eliminate aortic handling through the use of Y, T or extension grafts (Figure 4) (73) and have been described as safe and effective in preventing neurologic complications (38). As reflected by Class 1B recommendation in the 2018 ECS/EACTS guidelines (30), solid evidence supports the concept of “aortic no-touch” (17-26, 74-80) in patients with ascending aortic atherosclerosis (Table 1).
In a landmark paper by Calafiore (25) the presence of any aortic manipulation rather than the use of CPB itself was identified as an independent predictor of cerebrovascular accidents, especially in patients with extra-coronary vasculopathy. Similar results were shown by Patel (22), Kim (23), Kapetanakis (24), Vallely (26) and Moss (17): anOPCAB is consistently associated with significant neurologic benefit compared to strategies involving any aortic manipulation either on-pump or off-pump. Finally, Albert (20) reported a postoperative stroke rate as low as 0.49% in a series of 4,485 anOPCABs; although the study wasn’t randomized, a significant neurologic advantage of aortic no-touch was found especially for early stroke (0.09% vs 0.83%, p<0.0001). When comparing anOPCAB with the CABG arm of the SYNTAX trial a trend for lower stroke rate was found for anOPCAB at 1 year (0.8% vs 2.2%; p=0.07) (75); this became significant at 3-years (1.3% vs 3.4%; p=0.032) (78). Interestingly when anOPCAB is compared to the PCI arm no significant differences in terms of neurologic outcome is found at 1 and 3 years (1.3 vs 2.0%; p=0.347 and 0.8% vs 0.6%l p=NS), showing that surgical technique rather than the revascularization strategy affected the stroke rate. Similar results came from a network meta-analysis by Zhao (79): no difference in 30-day stroke risk when comparing anOPCAB with PCI (OR 0.92, 95% CI 0.47–1.78). The authors concluded that anOPCAB should be considered for reducing stroke risk in patient groups known to benefit most from surgical revascularization compared with PCI.
When looking solely at off-pump CABG performed with or without aortic manipulation, anOPCAB shows superior neurologic outcome both in a single center series (0.2% vs 2.2%, p=0.01) (21) and in two meta-analyses by Misfeld (80) (0.5% vs 1.4%; odds ratio, 0.46; 95% confidence interval, 0.29–0.72; I2=0.8%; p=0.0008) and Pawliszak (18) (0.36% vs 1.28%; risk ratio 95% CI: 0.41 (0.27-0.61); p<0.01; I2=0%).
Finally, a recent large network meta-analysis by Zhao (19) compared post-operative outcomes between all CABG techniques; 13 studies were included with a total of 37,720 patients (Figure 5). AnOPCAB was the most effective treatment for decreasing the risk of post-operative stroke (-78% vs. CABG, 95% CI 0.14 to 0.33; -66% vs. side-clamp OPCAB, 95% CI: 0.22 to 0.52; -52% vs. OPCAB-proximal anastomotic device, 95% CI: 0.27 to 0.86), mortality, renal failure, bleeding complications and atrial fibrillation.