Stroke and anaortic technique
Stroke is one of the most devastating adverse events of cardiac surgery and one that is most likely to impact long-term physical function, independence, and quality of life of our patients. Incidence of peri-operative stroke after CABG in the general population is 0.48-2.9%[5]. These cerebrovascular events arise from the disruption and dislodgment of atheromatous emboli by manipulation of the ascending aorta[14,15]. The risk is determined by the extent and severity of atherosclerotic aortic disease[5]. Van der Linden have found a nearly 5-fold increase in peri-operative stroke in patients with atherosclerotic ascending aorta disease compared to those without (8.7% vs 1.8%, p<.001)[27]. Involvement of more than half of the ascending aorta increased the risk of stroke to 33%. The risk of stroke is also determined by the degree of aortic manipulation as demonstrated by Zhao et al. Their meta analysis showed anaortic OPCAB to be the most effective technique in reducing stroke risk, decreasing cerebrovascular events by 78% compared to traditional on-pump CABG[14]. Further, fully anaortic OPCAB was demonstrated to be superior compared to OPCAB utilizing a proximal clamp and heart-string device, reducing stroke by 66% and 52% respectively[14]. Anaortic OPCAB is a well-established technique which in dedicated high-volume practices has been shown to lower risk of 30-day mortality (OR 0.42, p<.001), early complications, and length of hospital stay while providing equivalent long-term outcomes compared to standard CABG decades after surgery [25,26,28-31]. Further, OPCAB reduces operative blood loss and thus need for transfusion of blood products which are associated with adverse outcomes[32]. Further, OPCAB has been shown to benefit elderly patients, especially those with high calcific load, diabetes, and COPD, reducing their risk of death, stroke, and MI[13,16,33-35]. Finally, the anaortic approach allows for safe intervention in patients with a porcelain aorta, such as in our cohort, mitigating both the technical limitations the condition imposes and the excessive risk of stroke described above. This is reflected in the current guidelines - anaortic OPCAB is recognized as a Class I and Class 2a indication for surgical coronary revascularization in patients with a diseased aorta by EACTS 2018 and ACC/AHA 2021 guidelines respectively[13,16].
Likewise, transfemoral TAVR provides a safe and effective option for surgical treatment of aortic stenosis which is minimally invasive and does not require the manipulation of the aorta unlike traditional SAVR. In fact it is the only truly anaortic AVR technique. Strategies such as deep hypothermic circulatory arrest and use of apico-aortic conduit have been proposed, but none completely avoid aortic manipulation. Analysis of the TAVR arm of the PARTNER trial revealed severe aortic atherosclerotic disease to be the most common reason (46%) for patients to be considered inoperable due to technical reasons[36]. TAVR carries similar benefits to that of OPCAB - it reduces risk of mortality, bleeding and transfusion rates, while allowing for shorter hospital stays than SAVR[12] and has been found to carry a lower risk of postoperative stroke in high risk patients[17,37]. The choice of access site further dictates the outcomes of the TAVR procedure. The transfemoral approach has been shown to be definitively superior to transapical and transaortic in regards to risk of mortality and stroke[38,39]. The transaxillary approach is a reasonable alternative, however the most recent meta-analysis comparing the two access sites found it to carry significantly higher risk of mortality, stroke, and major vascular complications than transfemoral access[40]. The carotid artery is the most novel access site with equivocal mortality risk, but higher risk of stroke than the transfemoral approach[41]. The fully anaortic technique allowed by femoral access, as opposed to transaortic or transapical, is crucial in these high risk populations.
It is worth noting that while the anaortic technique is most valuable in this highly selected high risk population, it’s benefits through relative decrease in invasiveness, avoidance of aortic manipulation and cardiopulmonary bypass are also useful in those without above prohibitions and/or at lower surgical risk. These are proven, safe, non-inferior alternatives to traditional surgical management.
Combined OPCAB and TAVR have been described in previous studies, however aortic manipulation was involved in each one due to transaortic TAVR placement or proximal anastomoses in at least a subset of patients[18-21]. Our case series is the first to describe an entirely anaortic OPCAB combined with a transfemoral TAVR procedure. We have shown excellent results with device success achieved with no paravalvular leak on TEE in 100% of our cohort and complete revascularization achieved in 100% of patients. Our 30-day mortality rate was 0% and no patient suffered from myocardial infarction, stroke, or acute kidney injury in our cohort despite having significant atherosclerotic load. Removing significant aortic manipulation with the utilization of an anaortic OPCAB technique and a transfemoral TAVI is crucial in the avoidance of significant morbidity and mortality.
This study follows in the footsteps of many others in describing advances in techniques which allow us to now intervene in patients who hitherto have been prohibitively high risk or had anatomy, eg due to porcelain aorta, which did not allow for surgery. Despite the extent and invasiveness of the surgical intervention, risk of mortality and major adverse events is low even in octogenarians and nonagenarians[9,42-44]. By adopting and employing new techniques such as anaortic OPCAB and TAVR, we can minimize the cerebrovascular burden of intervention while providing excellent long-term results equivalent to standard therapy.