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J Am Coll Cardiol, 2007; 49:790-796, doi:10.1016/j.jacc.2006.10.052
(Published online 6 February 2007). © 2007 by the American College of Cardiology Foundation |



* Department of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany
Department of Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany
Department of Cardiology and Electrophysiology, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany
Department of Biomedical Statistics, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany.
Manuscript received July 20, 2006; revised manuscript received September 13, 2006, accepted October 16, 2006.
* Reprint requests and correspondence: Dr. Farhad Bakhtiary, Department of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe University Hospital, Theodor-Stern-Kai 7, 60596 Frankfurt/Main, Germany. (Email: farhad{at}bakhtiary.de).
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 [ClinicalTrials.gov] )
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