Acute improvement in arterial-ventricular coupling after transcatheter aortic valve implantation (CoreValve) in patients with symptomatic aortic stenosis

Abstract

The recent development of transcatheter aortic valve implantation (TAVI) to treat severe aortic stenosis (AS) offers a viable option for high-risk patients categories. Our aim is to evaluate the early effects of implantation of CoreValve aortic valve prosthesis on arterial-ventricular coupling by two dimensional echocardiography. Sixty five patients with severe AS performed 2D conventional echocardiography before, immediately after TAVI, at discharge (mean age: 82.6 ± 5.9 years; female: 60%). The current third generation (18-F) CoreValve Revalving system (Medtronic, Minneapolis, MN) was used in all cases. Vascular access was obtained by percutaneous approach through the common femoral artery; the procedure was performed with the patient under local anesthesia. We calculated, apart the conventional parameters regarding left ventricular geometry and the Doppler parameters of aortic flow (valvular load), the vascular load and the global left ventricular hemodynamic load. After TAVI we showed, by echocardiography, an improvement of valvular load. In particular we observed an immediate reduction of transaortic peak pressure gradient (P < 0.0001), of mean pressure gradient (P < 0.0001) and a concomitant increase in aortic valve area (AVA) (0.97 ± 0.3 cm(2)). Left ventricular ejection fraction improved early after TAVI (before: 47 ± 11, after: 54 ± 11; P < .0001). Vascular load, expressed by systemic arterial compliance, showed a low but significant improvement after procedure (P < 0.01), while systemic vascular resistances showed a significant reduction after procedure (P < 0.001). As a global effect of the integrated changes of these hemodynamic parameters, we observed a significant improvement of global left ventricular hemodynamic load, in particular through a significant reduction of end-systolic meridional stress (before: 80 ± 34 and after: 55 ± 29, P < 0.0001). The arterial-valvular impedance showed a significant reduction (before: 7.6 ± 2 vs after: 5.8 ± 2; P < 0.0001. Furthermore we observed a significant reduction with a normalization of arterial-ventricular coupling (P < 0.005). With regard to left ventricular (LV) efficiency, we observed, after the procedure, a significant reduction of stroke work (P < 0.001) and potential energy (P < 0.001), with a significant increase of work efficiency early after the procedure (P < 0.001). Our results showed that the TAVI procedure was able to determine an early improvement of the global left ventricular hemodynamic load, allowing a better global LV performance. Further follow-up investigations are needed to evaluate these results in a more prolonged time observation.