Angiographic Evaluation of Regurgitation through Normal Tricuspid and Mitral Valves of Dogs

Abstract

The evaluation of mitral or tricuspid insufficiency by analysis of the left or right atrial pressure curve is often unreliable, especially in mixed valve lesions. Left ventriculography is considered the most accurate method of estimating the degree of mitral insufficiency, but the literature is contradictory in respect to whether or not reflux occurs through a normal mitral valve (1, 2). Right ventricular angiography in the assessment of tricuspid insufficiency has received little attention. This study was undertaken to determine the frequency with which tricuspid or mitral insufficiency is demonstrated during ventricular angiocardiography in normal dogs. Method Thirty-six mongrel dogs were anesthetized with 27 mg/kg of sodium pentobarbital. In these animals 107 injections of contrast material were made (Table I), 53 of which were into the right ventricle. This ventricle was entered through the tricuspid valve from the right external jugular vein for 16 injections and from the femoral vein for 18. For the remaining 19 injections the catheter was passed retrograde into the right ventricle from an incision in the left pulmonary artery, so that the tricuspid valve was not traversed. Fifty-four injections were made into the left ventricle which was entered retrograde through the aortic valve via a left common carotid artery cut-down. Care was taken to assure that the left ventricular catheter was not near the mitral valve. For 74 injections, filming was with the Elema-Schönander cut-film changer at 4 per second for three seconds in the anteroposterior and/or lateral projections, and for 33 injections cineradiography was used at 32 frames per second in the lateral projection. One and one-half ml/kg of 75 per cent sodium diatrizoate5 was used for 78 injections and 1.0 ml/kg for 29. These volumes were selected, because in our laboratory 1.0—1.5 ml/kg of 75 per cent sodium diatrizoate is the maximum volume of contrast material used in a single injection in clinical angiocardiography. No. 8 multiple side-hole NIH catheters6 were used in 33 injections, and No. 11 catheters in the remainder. Pressure of injection was either 300 or 800 pounds per square inch, with a Cordis Injector. 7 These pressures were selected because in our laboratory 300 psi is considered an average injection pressure and 800 psi the maximum pressure which might be used during angiocardiography. With our injector a No.8 catheter delivers 13 ml/second at 300 psi and 23 ml/second at 800 psi, while a No. 11 catheter delivers 35 ml/second at 300 psi and 44 ml/second at 800 psi. Electrocardiograms were obtained during injections in most dogs. Three observers graded the roentgenograms or ciné film for reflux into the right or left atrium from 1+ (minimal) to 4+ (marked). Results In 43 of 53 right ventricular injections and in 43 of 54 left ventricular injections, valvular reflux into the corresponding atrium was detectable (Figs. 1 and 2). Thus, there was discernible regurgitation through a normal valve in 80 per cent of all the animals (Table II).