RESUMO
OBJECTIVE: To evaluate the CarboMedics (CM) prosthesis function two years after mitral valve replacement, and to compare the effective orifice area (EOA) calculated by pressure half-time (PHT) method and continuity method (CON). METHODS: Forty nine patients who underwent isolated mitral valve replacement with a CM prosthesis were recruited in this study, which included 13 cases of 25 mm CM prosthesis and 36 cases of 27 mm CM prosthesis. Two years after the mitral valve replacement, transthoracic echocardiography (TTE) was performed, measuring left ventricular ejection fraction (LVEF), stroke volume mean gradient (SV), PHT, peak early mitral diastolic velocity (E velocity), mean gradient (MG), time-velocity integral of left ventricular outflow tract/time-velocity integral of mitral valve prosthesis (TVI(MVP)/TVI(LVOT)). The function of the prosthetic valve was considered normal when PHT < 130 ms, E velocity < 2.0 m/s and TVI(MVP)/TVI(LVOT) < 2.2. RESULTS: More than half (53.1%) of the patients had normal function of the prosthetic valve. No significant differences were found in PHT, MG, TVI(MVP)/TVI(LVOT), EOA or IEOA between the patients with 25 mm valve and the patients with 27 mm valve (P > 0.05). But the patients with 25 mm valve had higher E velocity than the patients with 27 mm valve (P < 0.05). The PHT method produced greater EOA than by the CON method (P < 0.05). CONCLUSION: The function of CM prosthesis is acceptable two years after the mitral valve replacement, with most patients having PHT < 130 ms, E velocity < 2.0 m/s and TVI(MVP)/TVI(LVOT) < 2.2. PHT method produces greater EOA than CON method.
