Our objective is to develop, and utilize several ultrasonic techniques in the measurement of blood flow, pressure, and cardiac dimensions in acute and chronically instrumented animal models of cardiovascular disease and in patients undergoing coronary artery bypass surgery. The specific projects are: 1) The evaluation of the hemodynamics (velocity profiles, velocity waveform development, and pressure waveform development) of saphenous vein bypass (SVBP) grafts in man utilizing a multiple range gate 20 MHz pulsed Doppler previously developed and an extravascular tonometer to be developed, 2) using the hemodynamic information, develop and evaluate a simple to use ultrasonic flowmeter with inexpensive, isolated probes for use on S.V.B.P. grafts, 3) develop and evaluate in animals a pulsed echo/Doppler technique (10 and/or 20 MHz) for evaluating regional left ventricular funtion (via wall thickening) with the ability to separate endocardial and epicardial dynamics, 4) develop and evaluate in animals atraumatic vacuum attached transducers for the regional function measurements above and also for regional coronary flow sensing using the 20 MHz pulsed Doppler, 5) utilize the pulsed Doppler to evaluate velocity waveforms, and area reductions at arterial and venous microvascular anastamoses during reconstructive surgical procedures, and 6) develop an integrated ultrasonic measurement system for eventual intraoperative applications in patients using atraumatic techniques and capable of measuring blood velocity through native coronary arteries, volume blood flow through several bypass grafts, high fidelity pressure in each graft, and myocardial function in the epicardium and endocardium of several regions of the left ventricle.
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