Quantitation of experimental aortic regurgitation by roentgen videodensitometry

Abstract

Videodensitometry was employed to evaluate the presence and degree of aortic regurgitation in 4 anesthetized closed chest dogs with chronically implanted aortic electromagnetic flow transducers before and after the creation of aortic regurgitation by valvotomy. Angiograms were recorded on magnetic tape after injection of 4 to 6 ml of radiopaque material (Renovist), and videodensograms (roentgendensity-time curves) were recorded upstream and downstream to the aortic valve on replay of the video tape. The aortic regurgitant index (X) was calculated as the ratio of areas (in roentgen density·seconds) of the left ventricular and aortic videodensograms. Eighty-eight determinations, covering a wide range of aortic regurgitation, were made at heart rates ranging from 50 to 200 beats/min and compared to simultaneously obtained regurgitant indexes by electromagnetic flowmeter (F), F = 0.92 X − 0.01, r = 0.95, and by upstream-sampling indocyanine green dye-dilution technique (D), D = 0.91 X + 0.05, r = 0.92. Replicate measurements of the regurgitant index by Videodensitometry were closely similar. We believe that Videodensitometry provides a sensitive method for detection and estimation of the severity of aortic regurgitation, presumably applicable in man.