Discussion
Patients with BAV present with multiple configurations of the cusps, commissures, sinuses with/without additional aortopathy [13]. The mechanism of AR in BAV can be diverse. Cusp prolapse, fenestration or a restrictive cusp can cause AR. In addition, annulus dilatation or root enlargement can be existent. Therefore, during BAV repair, the surgeon has to consider all aspects of pathological changes in cusp and aortic root in order to restore the valve geometry [7]. Aortic valve repair is a feasible alternative to valve replacement that is referred to as Class IC indication in the 2017 European Association for Cardio-Thoracic Surgeons/European Society of Cardiology Guidelines for management of valvular heart disease [14]. Reconstruction of BAV has been already described in the 1990´s by Cosgrove and colleagues with triangular resection and plication of the prolapsing cusp [15]. We used that technique and modified it in our series to create a larger coaptation surface. The pericardial patch augmentation was evolved in addition to the mid-leaflet plication technique [5]. In patients with BAV and additional root dilatation we combined BAV repair with aortic valve reimplantation procedure (David procedure) to create a competent valve and restore the root geometry. We performed a subgroup analysis and compared the results of isolated BAV repair (group 1) with the David procedure in patients with BAV. In our series the in-hospital mortality was 1% (n=1) in group 1, and 2% (n=1) in group 2 (p=0.6). We did not observe any neurological events (stroke) perioperatively. The BAV repair data of our study demonstrate that it is a safe procedure and comparable to published in-hospital mortality rates between 0 and 1% [7,16]. CPB duration was significantly longer in group 2 (132±41 minutes in group 1 vs 191±52 minutes in group 2, p<0.01). Similar results were observed for cross-clamp time. This might be related to additional root reimplantation technique in Group 2 that is a complex procedure. The fact that significantly more patients of Group 1 received pericardial patch augmentation (89%) in comparison of Group 2 patients (71%, p<0.01) did not have an impact on the reoperation rate when comparing the two groups. The 5- and 10-year freedom from reoperation were similar in both groups, (p=0.83). Reported 10-year freedom from reoperation ranges between 78% and 81% in large series with BAV repair which is comparable to our results [16,17]. In our series, we observed a high number of endocarditis (n=7) at the late follow-up which was the cause of reoperation in 44% of patients. It is hard to explain why the observed endocarditis rate is so high. The aortic valve mean gradient was significantly higher in group 1 (17±12 mmHg) in comparison to group 2 (9±5 mmHg, p<0.01; Table 4). This could be related to a slightly higher aortic valve mean gradient of group 1 patients preoperatively that increased in course of time.
Pericardial patch augmentation seems to have a negative impact on AV repair durability as 92% of patients of Group 1 who had to be reoperated on the AV or had AR≥2° in the follow-up period received pericardial patch augmentation at time of primary operation. Similar results were observed in Group 2 (67%).
Our 5- and 10-year survival were good in both groups and did not differ significantly (p=0.31; Figure 2). Other published data with reported 10-year survival between 92% and 100% are comparable to our results [7,16,17]. The inferior 10-year survival in Group 1 in comparison to Group 2 might be related to a longer follow-up period of Group 1 and could also be influenced by more concomitant procedures at time of operation that have been performed in Group 1 (mitral and tricuspid valve procedures; Table 2). The cumulative linearized incidence of all valve-related complications (bleeding, stroke, endocarditis, reoperation) was 2.9% /patient-year in group 1, respectively 4%/patient-year in group 2, (p=0.6) which is lower to the reported incidence of prosthetic valve complications of 5% per patient per year [18]. Our results demonstrate that BAV repair techniques are safe and feasible. The mid-term durability of BAV repair is encouraging.