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.