Cause Of Valve Dysfunction Research Articles

Doppler echocardiography

Doppler echocardiography provides crucial information in the evaluation of a patient with suspected significant heart valve dysfunction. Doppler studies can provide quantitative data on the gradients across the stenotic valves and in many cases derive the actual valve area (with use of the pressure half-time method for stenotic atrioventricular valves or the continuity equation for semilunar valves). When combined with two-dimensional echocardiographic studies, Doppler studies may discern the cause of valve dysfunction. In valvular regurgitation, semi-quantitative estimation of the severity of the problem can be obtained by pulsed Doppler flow mapping or color Doppler echocardiography. These methods show great value for rapid evaluation of valve dysfunction in the emergency setting.

LONG-TERM (3 TO 13 YEARS) EVALUATION OF MITRAL VALVE REPLACEMENT WITH THE BIOPROSTHESIS

During a period of 1975-85, isolated mitral valve replacement (MVR) with the bioprosthetic valve was performed in 102 patients. The late complications and long-term durability of the bioprostheis were evaluated in 93 of the 102 patients who had survived more than 1 month postoperatively. The cumulative follow-up duration was 888.9 patient-years with a maximum follow-up of 13 years. Late mortality was 1.01%/patient-years (9 patients), and actuarial survival rate was 87% at 5 years and 76% at 13 years. Thrombo-embolic envents occurred in 5 times (0.67%/patient-years) and the probability of freedom from thromboembolic events at 13 years was 92%. Prosthetic valve endocarditis occurred in 4 times (0.45%/patient-years). Prosthetic valve dysfunction occurred 33 times (3.71%/pt-yrs) in 32 patients. Of 33 prosthetic valve dysfunctions, 32 were due to primary tissue failure (PTF). PTF was first experienced at 3 years postoperatively and rapidly increased after 6 years of surgery. The probability of freedom from prosthetic valve dysfunction at 13 years was 35%. Extended follow-up after MVR with the bioprosthesis confirms the satisfactory performance and lowthrombogenisity of this device up to 13 years after operation. PTF of the cusps remains the chief cause of valvedysfunction leading to reoperation and may represent a major problem.