Objectives: This prospective-randomized study investigated the effect of aortic valve design and patient-prosthesis mismatch (PPM) on coronary flow reserve (CFR) after mechanical or biological aortic valve replacement (AVR) in patients with aortic stenosis (AS). Background: Coronary flow reserve may be an important parameter of long-term survival after AVR in patients with AS. Reduced CFR may contribute to more cardiovascular events and greater rates of mortality. Methods: A total of 48 patients undergoing AVR underwent magnetic resonance imaging for the measurement of coronary flow preoperatively, 5 days postoperatively, and at 6-month follow-up with measurement of CFR. Patients scheduled for mechanical AVR were randomized to a tilting disc or bileaflet prosthesis (n = 12 in each group). For biological AVR, patients were scheduled to receive a stented (n = 12) or stentless (n = 12) valve. Patients also underwent echocardiography with measurement of transvalvular pressure gradients and left ventricular mass regression. Results: Postoperatively, coronary flow increased significantly in all groups (p < 0.001). Only stentless valves demonstrated a normal CFR (3.4 ± 0.3 vs. 2.3 ± 0.1 for stented biological valves, 2.1 ± 0.2 for tilting disc, and 2.2 ± 0.3 for bileaflet mechanical valves). Patient-prosthesis mismatch with an indexed effective orifice area <0.85 cm2/m2 led to decreased rates of CFR in the tilting disc, stentless, and stented groups. Pressure gradients were 14 ± 3 mm Hg for tilting disc, 12 ± 4 mm Hg for bileaflet, 19 ± 6 mm Hg for stented, and 10 ± 4 mm Hg for stentless valves. Conclusions: Normalization of CFR after AVR in patients with AS was observed only for stentless valves. Coronary flow reserve might explain the excellent long-term results for stentless valves. (Impact of Patient-Prosthesis Mismatch on Coronary Flow Reserve; http://www.clinicaltrials.gov/ct/show/NCT00310947?order=1; NCT00310947). © 2007 American College of Cardiology Foundation.
Bakhtiary, F., Schiemann, M., Dzemali, O., Dogan, S., Schächinger, V., Ackermann, H., … Kleine, P. (2007). Impact of Patient-Prosthesis Mismatch and Aortic Valve Design on Coronary Flow Reserve After Aortic Valve Replacement. Journal of the American College of Cardiology, 49(7), 790–796. https://doi.org/10.1016/j.jacc.2006.10.052