[Doppler echocardiographic measurement of flow velocity in cases with a Björk-Shiley aortic prosthesis and diagnosis of prosthetic valve dysfunction].

ABSTRACT

115 patients with a Björk-Shiley aortic valve prosthesis were studied by means of the ultrasonic Doppler method. The maximum flow velocity at the prosthetic valve was measured by the continuous wave Doppler method, and the velocity at the left ventricular outflow tract was measured by the pulsed wave Doppler method. In addition, flow velocity measured by Doppler method was compared to the valve opening angle obtained by cinefluoroscopy. 1) The maximum velocities at the prosthetic valve in the patients with normally functioning prosthesis were 3.1 +/- 0.4, 2.7 +/- 0.5, 2.2 +/- 0.4, 1.9 +/- 0.3, 1.7 +/- 0.3 m/sec for valve sizes of 21, 23, 25, 27, and 29 mm, respectively. Statistical differences were recognized between the valve size groups. In a case with a thrombosed valve, the maximum velocity was faster than in cases with normally functioning valves and it reached 4.5 m/sec. 2) Flow velocities at the left ventricular outflow tract in patients with normally functioning valves were 0.86 +/- 0.15, 0.86 +/- 0.16, 0.79 +/- 0.14, 0.82 +/- 0.16, 0.75 +/- 0.18 m/sec for valve sizes of 21, 23, 25, 27, 29 mm, respectively. No statistical difference was recognized. In the patients with perivalvular leakage, velocity was faster than in the patients with normally functioning valves. But, in the case with thrombosed valve, it remained within the normal range. 3) No significant correlation was observed between flow velocities and valve opening angles in the cases with normally functioning valves. But, in the cases with malfunctioning valves, flow velocities were faster than normal.(ABSTRACT TRUNCATED AT 250 WORDS)