sexta-feira, novembro 21, 2008
Estenose coronária vibrante.
Ultrasonic Doppler Vibrometry: Novel Method for Detection of Left Ventricular Wall Vibrations Caused by Poststenotic Coronary Flow
Volume 20(12), December 2007, p 1386–1392
Background: A diastolic coronary flow murmur has been reported for patients with coronary stenoses, yet is rarely appreciated during routine auscultation. We hypothesized that an ultrasonic Doppler method can detect the epicardial vibrations associated with this murmur. Ultrasonic Doppler vibrometry is a pulsed wave echocardiography phase demodulation technique designed for detecting vibrations. We correlated the vibration characteristics measured using vibrometry with the angiographic severity of coronary artery stenosis.
METHODS: In a prospective pilot study, 49 patients were recruited for an ultrasound examination before coronary arteriography. An ultrasound instrument was customized to acquire the raw pulsed wave Doppler echocardiographic data from a range gate placed on the left ventricular myocardium near the path of the epicardial coronary arteries.
RESULTS: Patients with angiographically minor stenosis (tightest stenosis < 50% by quantitative coronary angiography, N = 25) had lower diastolic vibration energy (computed as the median spectral energy of myocardial wall velocity in the 100~1000-Hz frequency band normalized by a baseline diastolic value) compared with patients with moderate or severe stenosis (any stenosis > 50%, N = 24) (P < .001, area under the receiver operating characteristics curve = 0.84). The vibration energy increased with increasing stenosis severity for less severe narrowing (<70%) but decreased for severe narrowing (>70%) (R2 = 0.21, P < .0002).
Conclusions: Preliminary evidence indicates that diastolic left ventricular wall vibrations measured using ultrasonic Doppler vibrometry are related to the severity of coronary artery stenoses. With further refinement and validation, this noninvasive and low-cost method could lead to an early screening and monitoring test for coronary artery stenosis.