Quantification of mitral regurgitation in the cardiac catheterization laboratory with contrast echocardiography

Background There is no method of quantifying the severity of mitral regurgi tation (MR) from injection of tracer directly into the left ventricular (LV ) cavity, a method commonly used in the cardiac catheterization laboratory. Methods and Results We used a previously validated mathematical model that derives regurgitant fraction (RF) From the relative tracer washout from the left atrial (LA) and LV cavities. Thirty-nine patients referred for diagno stic cardiac catheterization with clinical evidence of possible MR were inc luded in the study. Five milliliters of a microbubble mixture was power-inj ected into the IV during simultaneously performed contrast echocardiography . Relative changes in background-subtracted video intensity were measured f rom the LV and LA, and the resultant model-derived RF was correlated with t he severity of MR on cineangiography, The severity of MR ranged from 0 to 4 + on cineangiography with corresponding model-derived RF of 0 to 0.69 on co ntrast echocardiography. A close linear relation was noted between angiogra phic severity of MR and model-derived RF on contrast echocardiography (y = 0.1x + 0.03, r = 0.89, P <.001). Contrast echocardiography was more sensiti ve than cineangiography for detecting mild MR. Conclusions We describe a new method of measuring the severity of MR in the cardiac catheterization laboratory. Apart from being quantitative, this me thod can be safely used during cardiac catheterization in patients in whom iodinated contrast agents may be potentially harmful.