Background. Left ventricular hypertrophy (LVH) is the main compensatory mechanism to pressure overload in patients with aortic stenosis (AS). The increased left ventricular mass, related diastolic and coronary microcirculation dysfunctions (CMD) contribute to diastolic heart failure, clinical angina, arrhythmias and sudden death. Aortic valve replacement (AVR) leads to hemodynamic and metabolic improvement and to favorable changes in myocardial perfusion contributing to prolongation of survival. The aim of this study was to evaluate whether mechanical or porcine aortic prostheses differently impact diastolic dysfunction (DD) and CMD recovery after AVR for pure AS. Methods. Fifty patients having undergone AVR for pure AS with Medtronic Mosaic Ultra (MMU) bioprosthesis 21 mm (n=25) or St. Jude Medical Regent (SJR) mechanical valve 19 mm (n=25) were evaluated preoperatively and 12 months postoperatively comparing the hemodynamic behavior and the coronary flow by echocardiography and adenosine and rest cardiac magnetic resonance-myocardial perfusion imaging (CMR-MPI). Results. At 12 month follow-up significant differences in E/A ratio and isovolumetric relaxation time between the two groups were found. The E/A ratio decreased from 1.3 ± 0.2 to 0.8 ± 0.2 in the MMU group and from 1.1 ± 0.1 to 0.9 ± 0.1 in the SJR group (p<0.001). The isovolumetric relaxation time increased from 62 ± 5 msec to 83 ± 7 msec and from 60 ± 4 msec to 76 ± 5 msec, respectively (p=0.002). Stress-rest CMR-MPI revealed that myocardial perfusion reserve index (MPRI) increased from preoperative 1.57 ± 0.44 to 1.92 ± 0.32 (+19%) in the MMU group and from 1.58 ± 0.43 to 1.73 ± 0.26 (+9%) in the SJR group (p=0.04). Conclusions. Improvement of MPRI and DD recovery were more evident for bioprostheses than for mechanical valves, which may have some impact on exercise capability during normal daily life. The more physiological behavior of porcine valves could indicate a reassessment of traditional indications to the valve choice for AVR regardless of patient age.

CORONARY MICROVASCULAR AND DIASTOLIC DYSFUNCTIONS AFTER AORTIC VALVE REPLACEMENT: COMPARISON BETWEEN MECHANICAL AND BIOLOGICAL PROSTHESES

MANNACIO, VITO ANTONIO;VOSA, CARLO
2014

Abstract

Background. Left ventricular hypertrophy (LVH) is the main compensatory mechanism to pressure overload in patients with aortic stenosis (AS). The increased left ventricular mass, related diastolic and coronary microcirculation dysfunctions (CMD) contribute to diastolic heart failure, clinical angina, arrhythmias and sudden death. Aortic valve replacement (AVR) leads to hemodynamic and metabolic improvement and to favorable changes in myocardial perfusion contributing to prolongation of survival. The aim of this study was to evaluate whether mechanical or porcine aortic prostheses differently impact diastolic dysfunction (DD) and CMD recovery after AVR for pure AS. Methods. Fifty patients having undergone AVR for pure AS with Medtronic Mosaic Ultra (MMU) bioprosthesis 21 mm (n=25) or St. Jude Medical Regent (SJR) mechanical valve 19 mm (n=25) were evaluated preoperatively and 12 months postoperatively comparing the hemodynamic behavior and the coronary flow by echocardiography and adenosine and rest cardiac magnetic resonance-myocardial perfusion imaging (CMR-MPI). Results. At 12 month follow-up significant differences in E/A ratio and isovolumetric relaxation time between the two groups were found. The E/A ratio decreased from 1.3 ± 0.2 to 0.8 ± 0.2 in the MMU group and from 1.1 ± 0.1 to 0.9 ± 0.1 in the SJR group (p<0.001). The isovolumetric relaxation time increased from 62 ± 5 msec to 83 ± 7 msec and from 60 ± 4 msec to 76 ± 5 msec, respectively (p=0.002). Stress-rest CMR-MPI revealed that myocardial perfusion reserve index (MPRI) increased from preoperative 1.57 ± 0.44 to 1.92 ± 0.32 (+19%) in the MMU group and from 1.58 ± 0.43 to 1.73 ± 0.26 (+9%) in the SJR group (p=0.04). Conclusions. Improvement of MPRI and DD recovery were more evident for bioprostheses than for mechanical valves, which may have some impact on exercise capability during normal daily life. The more physiological behavior of porcine valves could indicate a reassessment of traditional indications to the valve choice for AVR regardless of patient age.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/596826
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