Valve prosthesis-patient mismatch (VP-PM): a long-term perspective

Seventeen-millimeter St. Jude Medical Regent valve in patients with small aortic annulus: dose moderate prosthesis-patient mismatch matter?

Background

The study was designed to evaluate the effects of moderate prosthesis-patient mismatch (defined as 0.65 cm²/m² < indexed effective orifice area ≤ 0.85 cm²/m²) on midterm outcomes after isolated aortic valve replacement with a 17-mm St. Jude Medical Regent valve in a large series of patients, and to determine if these effects are influenced by patient confounding variables.

Methods

One-hundred and six patients with and without moderate prosthesis-patient mismatch early after implantation of a 17-mm Regent valve at aortic position were included. Both clinical and echocardiographic assessments were performed preoperatively, at discharge and during follow-up period (mean follow-up time 52.6 ± 11.9 months).

Results

The prevalence of moderate prosthesis-patient mismatch was documented in 46 patients (43.4%) at discharge. During the follow-up period, no difference in the regression of left ventricular mass, decrease of transvalvular pressure gradients, mortality and prosthesis-related complications was observed between patients with and without moderate prosthesis-patient mismatch. After adjustment for several risk factors, moderate prosthesis-patient mismatch was associated with increased midterm mortality in patients with baseline left ventricular ejection fraction < 50% (HR: 1.80, p = 0.02), but with normal prognosis in those with preserved LV function. Younger age (cut off value = 65 years) was not an independent predictor of increased midterm mortality and valve-related complications in patients with moderate prosthesis-patient mismatch.

Conclusions

Moderate prosthesis-patient mismatch after aortic valve replacement with a small mechanical prosthesis is associated with increased mortality and adverse events in patients with pre-existing left ventricular dysfunction. Selected patients with small aortic annulus can experience satisfactory clinical improvements and midterm survival after aortic valve replacement with a 17-mm Regent valve.

Replacement of the st jude medical regent valve in the aortic position with a continuous suture technique in the small aortic root

BACKGROUND

The aim of this study is to review the strategy of performing aortic valve replacement (AVR) by using the St. Jude Medical (SJM) Regent valve with a continuous suture technique in patients with a small aortic root.

METHODS

Forty-six patients with small aortic annulus underwent AVR by using 19 or 21 mm SJM Regent valves. There were 15 males and 31 females. The mean age of the patients was 51.8 ± 12.4 years. The aortic annular diameter was 20.2 ± 0.9 mm. AVR procedures were performed with continuous suture technique using SJM Regent valves under standard cardiopulmonary bypass. Echocardiaographic data were collected before operation, at discharge, and at a follow-up time, respectively.

RESULTS

The intraoperative course was uneventful and there was no operative mortality. The implanted SJM Regent valves consisted of 21 mm valves in 15 patients and 19 mm valves in 31 patients. Echocardiography at 5.6 ± 1.3 months after operation showed a significant increase in the mean effective orifice area index (0.97 ± 0.24 cm(2) /m(2) ), decrease in the mean and peak transvavluar pressure gradient (12.5 ± 5.9 and 22.3 ± 9.6 mmHg), and decrease in the mean left ventricular mass index (106 ± 41.3 g/m(2) ). Moderate prosthesis-patient mismatch (PPM) (effective orifice area index between 0.65 and 0.85 cm(2) /m(2) ) was present in three patients and no severe PPM (effective orifice area index <0.65 cm(2) /m(2) ) occurred at discharge and during follow-up.

CONCLUSION

Replacement of SJM Regent valve with a continuous suture technique maybe a good option to prevent PPM in the aortic position.

Prosthesis-patient mismatch in aortic stenosis

BACKGROUND

The clinical impacts of prosthesis-patient mismatch (PPM) after aortic valve replacement (AVR) have been debated since Rahimtoola first reported PPM in 1978. Many reports discussing several aspects of PPM have been published to date, but the definitive clinical impacts of PPM have not yet been clarified.

PURPOSE

The purpose of this review is to evaluate recent articles regarding PPM and discuss the latest findings.

RESULTS

Moderate PPM (indexed effective orifice area ≤ 0.85 cm(2)/m(2)) did not affect the surgical outcomes in several papers, but severe PPM (indexed effective orifice area ≤ 0.65 cm(2)/m(2)) affected early and late mortality in almost of the all papers in which it was reported. PPM had a greater effect on younger patients and patients with left ventricular dysfunction than it did on elderly patients and patients with preserved left ventricular function.

CONCLUSION

Based on recent findings, it is difficult to define the impact of PPM after AVR. To some degree, PPM affects the clinical outcomes after AVR; therefore, it is important to avoid PPM, especially severe PPM.

Update on aortic valve prosthesis-patient mismatch in Japan

The influence of aortic valve prosthesis-patient mismatch (VP-PM) on the clinical outcome has been an ongoing controversy. The reported prevalence of VP-PM after aortic valve replacement (AVR) ranges widely between 20 and 70 %. The inconsistent impact of VP-PM on short-term and long-term mortality, regression of left ventricular (LV) hypertrophy, and exercise capacity may be explained by differences of the patient populations, the definition of VP-PM, and the use of different prostheses. Moreover, many factors other than the severity of VP-PM should be taken into account when considering its impact on individual patients after AVR. Although the concept of VP-PM is easy to understand, it cannot be applied to the whole patient population. In Japan, the age of the candidates for AVR has increased markedly in recent years, but almost all elderly patients with a small BSA (<1.6 m(2)) have received newer-generation prostheses with a small outer diameter and large effective orifice area. Indeed, previous studies of Japanese patients have demonstrated that VP-PM was no more than moderate in most cases and its impact on clinical outcomes was generally acceptable. Although severe VP-PM is infrequent and its clinical implications are still unproven in elderly Japanese patients, it would seem reasonable to try to prevent severe VP-PM. Thus, VP-PM itself cannot be accepted as an independent risk factor in Japanese patients, but the useful preventive strategies for severe VP-PM in inactive very elderly persons remain controversial. The implantation of newer-generation biological or mechanical prostheses with or without aortic annular enlargement should be considered according to the characteristics of the patient and the risk-benefit ratio for carrying out a particular procedure in an individual patient.

Comprehensive hemodynamic assessment of 368 normal St. Jude Medical mechanical mitral valve prostheses based on early postimplantation echocardiographic studies

BACKGROUND

Two-dimensional and Doppler-derived echocardiographic data on normal St. Jude Medical mechanical mitral valve prosthesis function have been reported but remain limited.

METHODS

Comprehensive retrospective two-dimensional and Doppler echocardiographic assessment of 368 normal St. Jude Medical mechanical mitral valve prostheses was performed early after implantation. The early postimplantation hemodynamic profiles of 98 patients were compared with profiles obtained by follow-up transthoracic echocardiography performed <13 months after implantation.

RESULTS

Using mean ± 2 SDs to define the normal distribution of values for Doppler-derived hemodynamic variables, the calculated normal ranges of values were as follows: mean gradient, 2 to 7 mm Hg; peak early mitral diastolic velocity (E velocity), 1.1 to 2.4 m/sec; time-velocity integral of the mitral valve prosthesis (TVIMVP) 20 to 50 cm; ratio of the TVIMVP to the time-velocity integral of the left ventricular outflow tract (TVILVOT), 0.9 to 2.5; pressure half-time, 35 to 99 msec; and effective orifice area, 1.12 to 3.24 cm(2). Patients with severe prosthesis-patient mismatch (ie, indexed effective orifice area ≤ 0.9 cm(2)/m(2)) had significantly higher mean gradients, E velocity, TVIMVP, and TVIMVP/TVILVOT. There was a trend for longer pressure half-times for patients with severe prosthesis-patient mismatch than for patients without severe prosthesis-patient mismatch, but none of these patients had pressure half-times > 130 msec. Among the 98 patients with follow-up transthoracic echocardiography <1 year after implantation, no significant differences were observed between early postimplantation findings and follow-up hemodynamic profiles.

CONCLUSIONS

This study establishes parameters (mean ± 2 SDs) defining the distribution of values for Doppler-derived hemodynamic data with normal St. Jude Medical mechanical mitral valve prostheses. Prostheses with hemodynamic values outside these parameters are likely dysfunctional; however, prosthesis dysfunction may be present even when hemodynamic values are within these ranges.