Although cardiopulmonary bypass support has been increasingly used for high risk coronary angioplasty, few data exist regarding its effects on left ventricular function. Accordingly, in 20 patients changes in left ventricular size, afterload and myocardial function were assessed by continuous hemodynamic monitoring and simultaneous two-dimensional echocardiography during cardiopulmonary bypass-supported high risk angioplasty. The cross-sectional left ventricular area during bypass support remained unchanged during diastole, whereas during systole it decreased (from 29.6 +/- 11.4 to 27.6 +/- 10.4 cm2, p less than 0.05). Global left ventricular function expressed as fractional area change remained unchanged from baseline to bypass support but decreased during balloon inflation (from 0.27 +/- 0.11 to 0.17 +/- 0.09, p less than 0.001). The end-systolic meridional wall stress decreased during bypass support (from 141 +/- 75 to 110 +/- 58 x 10(3) dynes/cm2, p less than 0.02). Regional myocardial function was assessed by a wall motion score (0 = normal, 1 = hypokinesia, 2 = akinesia and 3 = dyskinesia). Regions supplied by a stenotic (greater than or equal to 50% diameter) vessel deteriorated during bypass support (score from 0.9 +/- 0.8 to 1.06 +/- 0.8, p less than 0.01), whereas regions supplied by a nonstenotic vessel did not. Regions supplied by the target vessel deteriorated further during balloon inflation (score from 0.7 +/- 0.6 to 1.7 +/- 0.75, p less than 0.001). Thus, although left ventricular size and global function remain unchanged and afterload decreases during bypass support, myocardial dysfunction in regions supplied by a stenotic vessel may occur. Furthermore, regional and global left ventricular dysfunction still occur with angioplasty balloon inflation during cardiopulmonary bypass support.
Intravenous, sublingual, or aerosolized nitroglycerin was administered to 19 patients with coronary artery disease during clinically indicated cardiac catheterization. Eight blood samples were collected over 15 min from each patient, and analyzed for content of nitroglycerin, 1,2-glycerol dinitrate, and 1,3-glycerol dinitrate. Simultaneously, heart rate (HR), systolic blood pressure (SBP), and left ventricular end-diastolic pressure (LVEDP) were recorded. Plasma concentrations of nitroglycerin were highest after intravenous injection and lowest after sublingual tablets. Metabolite concentrations were highest after intravenous injection at early time-points; at later time-points, no between-group differences could be detected. SBP was minimally affected by intravenous nitroglycerin but was significantly reduced by sublingual and aerosolized formulations. Minor fluctuations in HR were observed in association with all three formulations. LVEDP was reduced by all three formulations of nitroglycerin but most rapidly by the intravenous form. Overall, no differences were detected in hemodynamic responses caused by sublingual and aerosolized nitroglycerin. Efficacy of sublingual and aerosolized nitroglycerin in patients undergoing cardiac catheterization is equivalent.
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