DISCUSSION
The aim of this study was to compare the mid-term outcomes of intermediate-risk patients operated on for severe AS with RDAVR with INTUITY, or TAVR with Sapien 3 valve. The main findings were: (1) At two years, there was a significantly lower occurrence of the composite criterion (death from any cause, disabling stroke and/or rehospitalization) in RDAVR group. (2) This result was mainly driven by less rehospitalization related to CHF in RDAVR group (3) Both valves provide a similar rate of PPM, PVR≥ 2 and PM implantation.
The recent progress in new generation THV urges surgeons to rethink surgical techniques. The INTUITY Valve is a hybrid option between conventional AVR and TAVR. RDAVR allows removal of the native leaflets as would a surgical procedure and is balloon-expanded as for TAVR. This enable to reduce CPBT by nearly 20 minutes compared to conventional AVR [18]. However, the clear benefit of this reduction on morbidity and mortality has not been demonstrated so far [19]. Thus, authors propose to limit its implantation to elderly patients in need of a combined surgery or in case of a complex aortic valve reoperation [20]. Meanwhile, indications for TAVR in patients with severe, symptomatic AS have been widely extended to younger patients since recent data showed that TAVR is non-inferior to surgery in intermediate and low risk patients [5,6].
While several studies have compared RDAVR with conventional AVR[13–15] and TAVR with conventional AVR[4–6], literature is poor on the direct comparison of RDAVR with INTUITY to TAVR with Sapien 3.
In this study, RDVAR with INTUITY provides better outcomes than TAVR with Sapien 3 at two-years FU. Based on the same composite criterion used in PARTNER 3, we showed a significantly lower rate of death from any cause, disabling stroke and/or rehospitalization in RDAVR group when compared to TAVR group. This was mainly driven by a lower rate of rehospitalization related to CHF in RDAVR group.
The ultimate goal of AVR is to decrease left ventricular (LV) afterload to allow LV mass regression and improve LV compliance and myocardial perfusion. This enhances survival and quality of life and decreases the risk for CHF.
CHF after TAVR is already known as a powerful predictor of mortality and multiple CHF readmissions predicted the highest mortality rates [21]. CHF symptoms develop usually in case of incomplete LV afterload relief, untreated mitral regurgitation or residual myocardial ischemia leading to increase in left atrial pressure and sPAP [22–24]. Interestingly, sPAP was significantly higher in TAVR group at one-month FU when compared to RDAVR group. Moreover, LVEF was similar in both groups as well as the rate of MR≥ 2. This suggests that other mechanisms could be involved in the increased risk of CHF in TAVR group.
Most TAVR patients had a history of coronary artery disease (CAD) but no standardized revascularization strategy was endorsed in the absence of guidelines [25]. Hence, the timing to perform percutaneous coronary intervention (PCI) before or after TAVR was at the discretion of the heart team. We assume that postponing PCI could have increase the risk of ischemic myocardial injury after the TAVR procedure. Conversely, most RDAVR patients had combined procedures with coronary artery bypass grafting (CABG), limiting the risk of residual myocardial ischemia, LV diastolic or systolic dysfunction and CHF.
Another explanation to understand the higher rate of CHF after TAVR could be an increased incidence of significant PVR. PVR is known as a powerful predictor of mortality and CHF after TAVR [26]. PVR could limit LV hypertrophy regression by exposing patients to a residual LV afterload, diastolic dysfunction and impaired coronary flow reserve. However, we didn’t find any difference regarding the occurrence of PVR≥ 2 in both groups. The rate of PVR≥ 2 was low in TAVR group(2,17%) in accordance with previous results reported in the literature [27].
The occurrence of PPM can also promote CHF after TAVR [28]. PPM leads to a lesser LV mass regression owing to the persistence of a residual LV afterload. However, the rate of moderate/severe PPM was similar between both RDAVR and TAVR groups in our study and could not explain a significantly higher rate of CHF in TAVR group.