Hemodynamic characterization of the Sorin Mitroflow pericardial bioprosthesis at rest and exercise
ABSTRACT Although the long-term clinical outcome after aortic valve replacement (AVR) with the Sorin Mitroflow pericardial bioprosthesis has been well described, few data are available with regards to hemodynamic performance. On the basis of its specialized design, with the pericardium mounted on the outside of the stent, the Mitroflow valve is considered to provide optimal opening and orifice areas.
Between February 2006 and April 2007, a total of 127 patients (66 females, 61 males; mean age 77.6 +/- 5.2 years) underwent AVR with the Mitroflow valve at the authors' institution. Echocardiography was performed at discharge in 91 patients, while a six-month follow up examination was conducted in 78 (including ergometer hemodynamics in 25 cases).
The mean systolic pressure gradient (MPG) ranged from 19.7 +/- 3.3 mmHg (size 19 valve) to 12.4 +/- 2.4 mmHg (size 27 valve), and the mean effective orifice area (EOA) from 0.96 +/- 0.0 cm2 (size 19 valve) to 2.36 +/- 0.4 cm2 (size 27 valve). The incidence of mild-to-moderate and severe prosthesis-patient mismatch (PPM) was 33% and 10% at the six-month follow up. During exercise (25 W-100 W), the MPG increased from 17.1 +/- 3.6 mmHg to 23.6 mmHg in valve sizes 19 to 21, and from 12.2 +/- 3.6 mmHg to 15.9 +/- 2.5 mmHg in valve sizes 23 to 27. The effective orifice fraction (EOF = EOA/annulus area) was 38 +/- 7%.
The Mitroflow valve exhibits an adequate MPG and EOA, as might be expected for a pericardial bioprosthesis. Of note, the gradient increase during exercise was low, especially for the larger valve sizes. Due to its special design, the Mitroflow prosthesis shows a large opening, as demonstrated by the high EOF. These data relating to the EOA of all prosthesis sizes may help surgeons to select the minimum prosthesis size in order to prevent PPM.
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ABSTRACT: OBJECTIVE: A multicentre experience with the Mitroflow pericardial bioprosthesis has been evaluated longitudinally over a 20-year period. METHODS: From 1988 through 2008, 1591 patients (mean age, 75.3±6.8 years, and 60.1% female) from 12 centres had a Mitroflow in the aortic position. Concomitant coronary artery bypass was performed in 41.9% (n=666) of patients, urgency/emergency surgery in 9.5% (n=152) and replacement of degenerated prosthesis in 2.3% (n=36). Follow-up (7.447 patient-years) was 99.2% complete. Median follow-up was 61.9 months (interquartile range (IQR) 30.8-90.9 months). The study was carried out following American Association for Thoracic Surgery/Society for Thoracic Surgeons/European Association for Cardio-Thoracic Surgery (AATS/STS/EACTS) Guidelines for reporting valve morbidity and mortality. RESULTS: The early (30-day) mortality was 6.5% (n=104). Actuarial survival rates at 10, 15 and 18 years were 53%, 34% and 27%, respectively (2.2 patient/year). Re-operation was required in 96 patients (5.9%), of whom 59 patients (3.7%) for structural valve degeneration. Actuarial freedom from prosthetic valve degeneration at 18 years was 65.5% (78% in patients>70 years) with a linearised rate of 1.4 patient/year (0.8 patient/year in patients>70 years). At 18 years, freedom from embolism was 82% (0.9 patient/year), freedom from valve endocarditis was 89% (0.6 patient/year) and freedom from bleeding episodes was 95% (0.2 patient/year), respectively. CONCLUSIONS: This independent multicentre study indicates that the Mitroflow pericardial bioprosthesis provides favourable long-term postoperative results with a low rate of valve-related events and need of re-intervention, particularly in patients older than 70 years.European Journal of Cardio-Thoracic Surgery 01/2011; 39(1). DOI:10.1016/j.ejcts.2010.03.069 · 2.81 Impact Factor
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ABSTRACT: Exercise hemodynamics play an important role in the evaluation and management of patients with both severe stenotic or regurgitant valve lesions. Exercise testing in patients with valvular heart disease can help to unmask latent symptoms and define the timing of surgical intervention. Additionally, exercise-induced hemodynamics are an important tool to assess prosthetic valve function. This review summarizes both background literature and recent publications that assess the use of exercise hemodynamics in the evaluation and management of valvular heart disease.Current Cardiology Reports 02/2011; 13(3):226-33. DOI:10.1007/s11886-011-0169-2
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ABSTRACT: The hemodynamics in proximity to stented aortic bioprostheses still differ from that under physiological conditions. This may prevent desired cardiac remodeling and promote aortic diseases. Further improvements in prosthetic technology require an accurate survey of the flow conditions on the prosthetic level and in the ascending aorta. Cardiovascular magnetic resonance (CMR) may have the potential to provide more information by determining the prosthetic orifice area and visualizing the intravascular flow dynamics. We tested the feasibility to better characterize the hemodynamics of various stented bioprostheses in a pulsatile flow phantom by using CMR. The custom-made model consisting of a commercially available pump generating pulsatile flow, a tube system filled with a glycerin-water mixture, and a handcrafted bulbar-shaped cylinder holding the bioprostheses and simulating the aortic root, was located in a clinical 1.5T CMR system. In this study, 10 stented aortic bioprostheses were investigated (Perimount® 21, 23; Mitroflow® 19, 25; Hancock® 21, 23, 25; Mosaic® 21; Epic Supra® 21, 23). The prosthetic orifice area was visualized using steady-state free-precession cine imaging (spatial/temporal resolution 1.3×1.3×5 mm³/29 ms), quantified by manual planimetry and compared with published transthoracic echocardiographic data. Time-resolved three-dimensional phase-contrast flow mapping (1.8×1.8×3 mm³/45 ms) was applied to analyze the transprosthetic flow pattern. Visualization of the prosthetic orifice area and the transprosthetic flow pattern was feasible in all prostheses. All orifice areas obtained by CMR in vitro were within one standard deviation of the mean of the published reference values obtained by echocardiography in vivo. Turbulent flow with vortex formation occurred both in proximity to the prosthesis and on the 'ascending aortic' level. Larger prosthetic sizes led to decreased flow velocities, but not mandatorily to less turbulences. CMR allowed for a detailed interrogation of the fluid dynamics of various heart valve bioprostheses in a pulsatile flow model. It is an attractive tool to define proprietary reference values of the orifice area under standardized conditions and provides novel information regarding the flow pattern in proximity to the prosthesis.European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 02/2011; 40(3):736-42. DOI:10.1016/j.ejcts.2010.12.040 · 2.81 Impact Factor