Impact of the indexed effective orifice area on mid-term cardiac-related mortality after aortic valve replacement.

BACKGROUND: There has been ongoing controversy as to whether prosthesis-patient mismatch (PPM, defined as indexed effective orifice area (EOAI) <0.85 m(2)/cm(2)) influences mortality after aortic valve replacement (AVR). In most studies, PPM is anticipated by reference tables based on mean EOAs as opposed to individual assessment. These reference values may not reflect the actual in vivo EOAI and hence, the presence or absence of PPM may be based on false assumptions. OBJECTIVE: To assess the impact of small prosthesis EOA on survival after aortic valve replacement AVR. METHODS: 645 patients had undergone an AVR between 2000 and 2007 entered the study. All patients underwent transthoracic echocardiography for determination of the actual EOAI within 6 months postoperatively. In order to predict time from surgery to death a proportional hazards model for competing risks (cardiac death vs death from other causes) was used. EOAI was entered as a continuous variable. RESULTS: PPM occurred in 40% of the patients. After a median follow-up of 2.35 years, 92.1% of the patients were alive. The final Cox regression model showed a significantly increased risk for cardiac death among patients with a smaller EOAI (HR=0.32, p=0.022). The effect of EOAI on the 2-5 year mortality risk was demonstrated by risk plots. CONCLUSIONS: In contrast to previous studies these EOAI values were obtained through postoperative echocardiography, substantially improving the accuracy of measurement, and the EOAI was modelled as a continuous variable. There was a significantly improved survival for larger EOAIs following AVR. Strategies to avoid PPM should become paramount during AVR.

Hemodynamic characterization of the Sorin Mitroflow pericardial bioprosthesis at rest and exercise.

BACKGROUND AND AIM OF THE STUDY: 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. METHODS: 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). RESULTS: 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%. CONCLUSION: 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.

Twenty-year experience with the St. Jude medical Biocor bioprosthesis in the aortic position.

BACKGROUND: The purpose of this study was to evaluate the long-term performance of the St. Jude Medical Biocor stented porcine prosthesis in the aortic position. METHODS: From January 1985 to December 1996, 455 patients admitted for aortic valve replacement were consecutively enrolled in this study. The mean age was 72.5 +/- 9 years, 18 patients (3.5%) had had previous cardiac surgery, and coronary artery bypass grafting was performed in 171 patients (37.6%). Follow-up was complete in 99.6%; up to 21 years were covered. Actuarial event-free rates are given as mean +/- standard error and adverse events were classified according to the guidelines for reporting morbidity and mortality after cardiac valvular operations. RESULTS: Cumulative follow-up time was 3,321 patient-years with a mean follow-up of 8.2 years. The actuarial survival rate after 20 years was 9.4% +/- 2.8%. The actuarial rates for freedom from structural valve deterioration were 93.1% +/- 1.7% at 10 years, 88.4% +/- 3.5% at 15 years, and 70.3% +/- 10.9% at 20 years. The actuarial rates for freedom from reoperation due to structural valve deterioration were 91.9% +/- 1.6% at 10 years, 90.6% +/- 2.1% at 15 years, and 86.5% +/- 4.5% at 20 years. CONCLUSIONS: This study presents one of the largest series of St. Jude Medical Biocor aortic valves in the world. Results indicate an age-dependent risk of structural valve degeneration beginning as soon as 7 years postoperatively for patients below the age of 65 years, but show a low overall incidence of valve-related complications and excellent durability.

Hemodynamic performance of the new St. Jude Medical Epic Supra porcine bioprosthesis in comparison to the Medtronic Mosaic on the basis of patient annulus diameter.

BACKGROUND AND AIM OF THE STUDY: The St. Jude Medical Epic Supra (ES) valve is a new porcine bioprosthesis designed for complete supra-annular implantation. To date, no in-vivo data regarding the hemodynamic and clinical performance of this valve are available. The study aim was to compare the hemodynamic performance of the ES valve with the completely supra-annular Medtronic Mosaic (MM) porcine valve. METHODS: Between July 2000 and April 2006, 83 patients (39 males, 44 females) underwent aortic valve replacement with either the ES (n = 44) or MM (n = 39) bioprosthesis. Hemodynamic performance was evaluated echocardiographically at six months postoperatively. Comparison between the valves was performed by dividing the patient groups according to their intraoperatively measured tissue annulus diameter rather than the labeled valve size. RESULTS: The internal diameter and sewing ring diameter differed in ES and MM valves with the same labeled size. For example, in valves labeled '23' the internal diameter/sewing ring diameters were 21.5 and 29.3 mm in the ES valve versus 20.5 and 30 mm in the MM. The mean pressure gradients (MPG) for patients with ES or MM valves were 15.5 +/- 4.5 or 14.8 +/- 5.1 mmHg for annulus diameter < or =22 mm, 14.6 +/- 6.4 or 13.9 +/- 3.6 for annulus diameter 23-24 mm, and 15.3 +/- 3.8 or 13.4 +/- 4.2 mmHg for annulus diameter > or =25 mm. No significant differences were identified in the hemodynamic data, including MPG, effective orifice area (EOA) and effective orifice area index (EOAI). The incidence of moderate or severe patient-prosthesis mismatch (PPM) was 40% (n = 18) and 5% (n = 1) in patients with ES valves, and 26% (n = 10) or 23% (n = 9) in patients with MM valves (p = 0.01). In patients with an annulus size < or =22 mm, severe PPM occurred in 29% (n =5) of patients with MM valves but in none of those with ES valves. CONCLUSION: The hemodynamic performance of the ES valve was comparable to that of the well-established MM valve. The incidence of severe PPM was lower in patients with ES valves than MM valves, presumably due to the somewhat larger EOA values in patients with a small aortic annulus (<25 mm).