[Mitral prostheses with and without dysfunction: evaluation using 2-D Doppler echocardiography]

Abstract

Study objective: To evaluate the flow characteristics of normal and abnormal functioning mechanical and bioprosthetic (B) mitral valves.

Design: Prospective study in patients submitted to mitral valve replacement.

Setting: Laboratory of Echocardiography at Santa Marta Hospital.

Patients: 61 consecutive and asymptomatic patients with normally functioning mitral prosthesis (prt)--37 Bjork-Shiley (B-S), 11 Carpentier-Edwards (C-E), 5 Hancok (HAN), 7 Ionescu-Shiley (I-S) and 1 Wessex--and 15 pts with abnormal prosthetic function (6 B-S, 5 Hall-Kaster, 2 C-E, 1 I-S and 1 HAN).

Intervention: Prosthetic mitral flow record, using 2D-Doppler echocardiography, to analyse: peak velocity (PV), peak gradient (PG), mean gradient (MG), pressure half time (PHT), area (A) and presence of regurgitation (R).

Results: Normally functioning prosthetic valves--PV ranged from 88 to 186 cm/s (134.6 +/- 24.3) in B-S prt and 133 to 198 cm/s (157.4 +/- 18.8) in B, p less than 0.0001. The prt B-S showed a greater PG (10.3 +/- 2.5 vs 7.6 +/- 2.6 mmHg), MG (3.1 +/- 1.1 vs 2.6 +/- 1 mmHg) and smaller area (2.3 +/- 0.4 vs 2.5 +/- 0.4 cm2) then Bioprosthetic ones, p less than 0.0001, p = 0.003, p = 0.003 respectively. There was a significant correlation between PG and MG: r = 0.84, r = 0.87, r = 0.84 respectively in B-S prt, Bioprosthesis and both, p less than 0.001. Mild regurgitation was present in 8 pts with prt B-S and 4 with B. Malfunctioning prosthetic valves--The mean of PV was 238.5 +/- 29.2 cm/s in prt B-S compared to 265.48.2 +/- 48.2 cm/s in B. Significant regurgitation, was detected by Doppler technic in 100% of B and 72% of mechanical prt. PV greater than 2 m/s has a 100% sensitivity and specificity to separate normal from abnormal prosthesis function.

Conclusions: These data may be useful as reference values to the follow-up of pts with these types of prt. The prt B-S seems to have more optimal hemodynamics profile than B ones. Protodiastolic transprosthetic PV greater than 2 m/s suggest abnormal functioning valve. PG is a significant determinant of MG.