Comparison of the hemodynamic performance of percutaneous and surgical bioprostheses for the treatment of severe aortic stenosis

Hemodynamic results and changes in myocardial function after transcatheter aortic valve implantation

BACKGROUND

This prospective study was designed to evaluate the hemodynamic results of transcatheter aortic valve implantation (TAVI) with the CoreValve prosthesis (Medtronic, Minneapolis, Minnesota) and the effects on left ventricular function.

METHODS

From June 2008 to June 2009, consecutive patients with severe symptomatic aortic valve stenosis (aortic valve area <1 cm(2)) and the indication for TAVI were included. Aortic valve prosthesis was inserted retrograde. Examinations of study patients were performed before, 30 days, and 6 months after TAVI and comprised measurement of B-type natriuretic peptide and echocardiography. Severe prosthesis-patient mismatch was defined as an indexed effective aortic valve area < or =0.65 cm(2)/m(2).

RESULTS

In 39 patients, follow-up examinations were performed after TAVI. Severe prosthesis-patient mismatch seldom occurred (n = 1), but mild to moderate aortic valve regurgitation due to paravalvular leaks was common (n = 24, 62%). After 6 months, left ventricular mass index declined (158 +/- 46 vs 138 +/- 45 g/m(2), P = .001), and peak early diastolic mitral annular velocity (E') and peak systolic mitral annular velocity (S') increased (P = .004 and P < .001, respectively). B-type natriuretic peptide levels decreased (744 +/- 708 at baseline vs 367 +/- 273 at 30 days, P = .003, 279 +/- 186 pg/mL at 6 months, P = .001). Left ventricular diameters and ejection fraction remained unchanged.

CONCLUSION

Despite the high incidence of paravalvular regurgitation after TAVI, hemodynamic results were favorable. Furthermore, TAVI had positive effects on left ventricular remodeling and improved neurohormonal activity, myocardial hypertrophy, and diastolic function.

Absence of prosthesis-patient mismatch with the new generation of Edwards stented aortic bioprosthesis

Prosthesis-patient mismatch (PPM) remains a controversial issue with the most recent stented biological valves. We analyzed the incidence of PPM after implantation of the Carpentier-Edwards Perimount Magna Ease aortic valve (PMEAV) bioprosthesis and assessed the early clinical outcome. Two hundred and seventy consecutive patients who received a PMEAV bioprosthesis between January 2007 and July 2008 were analyzed. Pre-, peri- and postoperative data were assessed and echocardiographic as well as clinical follow-up was performed. Mean age was 72+/-9 years, 168 (62.2%) were males. Fifty-seven patients (21.1%) were below 65 years of age. Absence of PPM, corresponding to an indexed effective orifice area >0.85 cm(2)/m(2), was 99.5%. Observed in-hospital mortality was 2.2% (six patients), with a predicted mortality according to the additive EuroSCORE of 7.6+/-3.1%. At echocardiographic assessment after a mean follow-up period of 150+/-91 days, mean transvalvular gradient was 11.8+/-4.8 mmHg (all valve sizes). No paravalvular leakage was seen. Nine patients died during follow-up. The Carpentier-Edwards PMEAV bioprosthesis shows excellent hemodynamic performance. This valve can be implanted in all sizes with an incidence of severe PPM below 0.5%.

Paradoxical low flow and/or low gradient severe aortic stenosis despite preserved left ventricular ejection fraction: implications for diagnosis and treatment

Paradoxical low flow, low gradient, severe aortic stenosis (AS) despite preserved ejection fraction is a recently described clinical entity whereby patients with severe AS on the basis of aortic valve area have a lower than expected gradient in relation to generally accepted values. This mode of presentation of severe AS is relatively frequent (up to 35% of cases) and such patients have a cluster of findings, indicating that they are at a more advanced stage of their disease and have a poorer prognosis if treated medically rather than surgically. Yet, a majority of these patients do not undergo surgery likely due to the fact that the reduced gradient is conducive to an underestimation of the severity of the disease and/or of symptoms. The purpose of this article is to review and further analyse the distinguishing characteristics of this entity and to present its implications with regards to currently accepted guidelines for AS severity.

[Surgery or medical therapy for secondary mitral regurgitation?]

Mitral regurgitation (MR) is the second most frequent valve disease in Europe. In addressing the current therapy for MR, it is useful to distinguish primary from secondary or functional MR. In primary MR, there is derangement of the mitral valve itself causing left ventricular volume overload and left ventricular dysfunction. By contrast, in secondary MR, the valve and its components are typically normal and MR is related to changes of annular size (dilatation) and papillary muscle displacement due to left ventricular damage caused by myocardial infarction or dilated cardiomyopathy.In primary MR, mitral valve repair or replacement is the first-line therapy. In secondary MR, the best management includes standard medical therapy for heart failure and cardiac resynchronization therapy in selected patients. Since there is no evidence from randomized studies that surgery improves mortality, this approach may only be considered in patients who remain symptomatic despite optimal medical therapy or in patients undergoing coronary revascularization.