Mitroflow pericardial bioprosthesis experience in aortic valve replacement > or =60 years of age

Early structural degeneration of Mitroflow aortic valve: another issue in addition to the mismatch?

We reported two cases of early structural valve degeneration (SVD) with Mitroflow prosthesis in aortic position in patients above the age of 65 years. Microscopic aspects have been analysed to investigate the intrinsic mechanism of SVD. New techniques to improve the structure and the preservation of this prosthesis are needed in order to reduce potential dangerous early complications.

Sutureless perceval aortic valve replacement: results of two European centers

BACKGROUND

The Perceval S bioprosthesis (Sorin Biomedica Cardio Srl, Sallugia, Italy) is a self-expanding valve designed to preserve aortic sinuses and sinotubular junction. We report the midterm results of a prospective, multicenter clinical study evaluating the safety and efficacy of this stented bioprosthesis in patients undergoing aortic valve replacement with or without concomitant procedures.

METHODS

From January 2007 to September 2011, a total of 208 high-risk patients (mean European system for cardiac operative risk evaluation: 8.7±5.3 years) received a Perceval bioprosthesis in 2 European centers. Median follow up was 10±20 months and 100% complete, and the total accumulated follow-up was 156 patient-years. Ten patients have reached a 4-year follow-up. Valve function was assessed in all patients.

RESULTS

Valve implantation resulted in significant improvement of patients' symptoms. Mean preoperative and postoperative gradients were 48.6±18.6 mm Hg and 10.4±4.3 mm Hg, respectively, and preoperative and postoperative mean effective orifice areas were 0.7±0.2 and 1.4±0.4 cm2. Survival at 12 months was 87.1%, success of implantation was 95%, and freedom from reoperation was 96%. In hospital mortality was 2.4%. During follow-up, 9 patients (4%) required reoperation for paravalvular regurgitation; 7 early and 2 late reoperations. Mean cross-clamp time (CCT) and extracorporeal circulation time (ECT) were, respectively, 33±14 minutes and 54±24 minutes, including 45 patients who underwent surgery through ministernotomy. Concomitant coronary bypass was done in 48 patients with mean CCT 43±13 and ECT 68±25 minutes.

CONCLUSIONS

Perceval sutureless is a safe bioprosthesis that can easily be implanted, including by a minimally invasive technique. It provides excellent hemodynamic with significant clinical improvement. Overall, these data confirm the safety and utility of the Perceval bioprosthesis aortic valve replacement for high-risk patients.

Future of cardiac surgery: minimally invasive techniques in sutureless valve resection

Aortic valve replacement with mechanical or biological heart valves is the treatment of choice for aortic valve stenosis when it is symptomatic or with severe aortic stenosis (≤ 0.6 cm2/m2) or with left ventricular dysfunction. In an effort to improve the outcomes of patients with stented biological valves, stentless valves were introduced to clinical practices in the early 1990s. Theses valves were designed to be less obstructive, and thus result in a lower transvalvular gradient. Technically the implantations of these valves are more demanding resulting in longer cross clamp and bypass times. However, important comorbid conditions in elderly patients referred for aortic valve replacement require alternative treatment options with possible reductions of the extracorporeal bypass time and reliable hemodynamic features. In order to comply with these requirements, percutaneous valves and sutureless surgical valves have been developed. The percutaneous technique has the advantage of being performed without circulatory bypass but leaving the aortic calcifications in place, thereby resulting in a high degree of paravalvular insufficiency, atrioventricular block and strokes. The surgical approach has the advantage of removing all calcifications and the valves can be optimally implanted, resulting in minimal paravalvular leak with a low incidence of atrioventricular block and strokes; however, it requires cardiopulmonary bypass. In addition, it can be performed with a low mortality (<3% in isolated aortic replacement, even in older patients). This article reviews the various techniques, strength and limitations of these sutureless valves implanted in the aortic position.

Mitroflow Synergy Prostheses for Aortic Valve Replacement: 19 Years Experience With 1,516 Patients

BACKGROUND

Pericardial prostheses have been used as valvular substitutes since 1975. They combine excellent hemodynamic characteristics with a low risk of valve failure during long-term observation. The aim of this article is to describe the clinical long-term performance of the Mitroflow Synergy pericardial valve (Sorin Group Inc, Mitroflow Division, Vancouver, Canada) in the aortic position for as long as 19 years.

METHODS

Data were obtained between February 1985 and April 2004 from patients with aortic heart valve replacements (n = 1,464) or from patients with replacements of existing prosthetic aortic valves (n = 52). The age group distributions are less than 70 years (n = 175); 70 to 74 years (n = 462); 75 to 79 years (n = 532); 80 to 84 years (n = 273); and greater than or equal to 85 years (n = 74). The cause of the aortic valve lesions was combined (insufficiency and stenosis) in the majority of patients (62.4%). Concomitant procedures were performed in 897 patients (59.2%) and coronary artery bypass grafting was the most common (53.5%). Mean follow-up was 5.5 +/- 0.09 years. Total follow-up was 8,408 patient-years.

RESULTS

The early mortality (30 days) was 6.6% (n = 99) and late deaths were 60.8% (n = 921). Actuarial event-free rates at 5, 10, and 15 years of follow-up are given as mean +/- standard error for endocarditis: 96.9 +/- 0.5, 92.8 +/- 1.2, and 92.0 +/- 1.4, respectively; embolism: 96.7 +/- 0.6, 88.8 +/- 1.7, and 82.9 +/- 3.5, respectively; bleeding: 98.5 +/- 0.4, 97.2 +/- 0.6, and 94.4 +/- 1.7, respectively; structural valve deterioration: 99.0 +/- 0.3, 82.8 +/- 2.2, and 62.8 +/- 5.8, respectively; and reoperation: 98.2 +/- 0.4, 79.2 +/- 2.4, and 63.4 +/- 5.3, respectively. The rate of endocarditis, structural valve degeneration, and reoperation was lower in patients 75 years of age and older compared with younger patients, whereas embolism occurred more frequently in elderly than in younger patients.

CONCLUSIONS

Adverse events after implantation of Mitroflow aortic bioprosthesis rarely occurred during the first 5 years after valve replacement. The results of the prosthesis indicates reliable long-term morbidity rates and good durability in patients 75 years of age and older.

Hydrodynamic function of the second-generation mitroflow pericardial bioprosthesis

BACKGROUND

The hydrodynamic function of the smaller size Mitroflow Synergy stented pericardial bioprostheses has been studied in an in vitro fresh tissue aortic root model and compared with previous studies of free-sewn bioprostheses.

METHODS

Three valves of each of the sizes 19, 21, and 23 mm were sutured into fresh tissue aortic roots and tested in a pulsatile flow simulator using two different ventricular input impedance conditions. A high-speed camera was used to study the leaflet opening and closing configurations. Mean pressure difference as a function of root mean square forward flow, effective orifice area, regurgitant volumes, and total energy loss across the valves was measured.

RESULTS

Mean pressure difference with respect to root mean square forward flow decreased as the valve size increased. Thus effective orifice area increased as the valve size increased. The open leaflet configuration images showed that all three sizes of Mitroflow valves had a large circular orifice with minimal open leaflet deformation. All valves closed competently with no visible leakage and no closed regurgitant volume. The Mitroflow valves showed better effective orifice areas compared with previously tested frame-mounted porcine bioprostheses but lower effective orifice areas compared with porcine stentless bioprostheses; however, the open leaflet bending deformation was better than for any of the previously tested bioprosthetic valves.

CONCLUSIONS

The hydrodynamic function of the Mitroflow Synergy stented pericardial bioprosthesis shows potential for good in vivo hemodynamic performance. The good hemodynamic performance combined with relative ease of implantation technique makes the pericardial valve a good valve in the aortic position, particularly in older patients with small annuli.