Hemodynamic characteristics of Edwards Sapien aortic valve prosthesis assessed with transesophageal echocardiography

Transcatheter aortic valve implantation (TAVI) has become the therapy of choice in high-risk patients with aortic stenosis. Transesophageal echocardiography provides important anatomic and functional information before, during, and after any procedure. The study aim was to determine the hemodynamic properties of 23 and 26 mm Edwards Sapien (ES) valves immediately after implantation, and to compare these data to those previously reported for surgically implanted valves.

A total of 284 patients treated with transapical TAVI (90 patients with ES 23 mm valves, 194 with ES 26 mm valves) for severe aortic stenosis was analyzed. Quantitative echocardiographic data were obtained both pre- and post-procedure, and stored. Measurements were also made of the aortic annulus diameter, and the effective orifice area (EOA) was also calculated. In addition, the effective energy loss coefficient, as a parameter of left ventricular (LV) workload assessment, was determined. For risk estimation of prosthesis-patient mismatch (PPM), the EOA was indexed by body surface area; typically, an iEOA value < 0.65 cm2/m2 was considered indicative of PPM.

The LV systolic function, assessed as biplane ejection fraction (EF) was improved significantly (pre-procedure 53 +/- 17% versus post-procedure 59 +/- 14%; p < 0.0001). The improvement was more pronounced in patients with a reduced preoperative function (correlation between AEF and EF pre; R = -0.55, p < 0.00001). The peak post-procedure pressure gradients in the 23 mm and 26 mm groups were 11.9 +/- 6.3 and 9.5 +/- 5.2 mmHg, respectively, the mean pressure gradient was 6.3 +/- 3.4 and 5.0 +/- 2.6 mmHg, and the EOA was 1.55 +/- 0.36 and 1.85 +/- 0.42 cm2. In 7.2% of all patients (10.1% in the 23 mm group and 5.8% in the 26 mm group; p = 0.30), the post-procedure iEOA was below the borderline value for PPM.

The main hemodynamic characteristics of the Edwards Sapien valves were low peak and mean pressure gradients, and a low incidence of PPM after TAVI. The EOA was highly comparable with that of stented and stentless biological prostheses used for conventional aortic valve surgery. An ability to maintain these favorable hemodynamic characteristics of the ES valves during a long-term follow up would serve as a strong argument to extend the indication for TAVI to lower-risk patients.