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D R Abendschein

Publications and source records attributed to D R Abendschein.

77 records · Page 5Linked to original sources
PubMed1978

Protection of ischemic myocardium by whole-body hypothermia after coronary artery occlusion in dogs.

Anesthetized dogs were cooled to a core body temperature of 26 degree C. or maintained at a body temperature of 37 degree C. during periods of 5 and 10 hours of LAD coronary artery occlusion. Subsequent macroscopic dehydrogenase enzyme mapping showed that ischemic injury was 25 per cent less after 5 hours of coronary occlusion and 20 per cent less after 10 hours of occlusion in hypothermic dogs than in normothermic controls. The heart rate and left ventricular minute work in hypothermic dogs decreased to roughly half the levels measured in normothermic animals, while left ventricular contractility was 10 to 40 per cent lower in hypothermic dogs than in normothermic dogs. However, cardiac index and left ventricular end-diastolic pressure were unchanged by whole-body cooling. Thus, hypothermia appeared to diminish the oxygen requirements of the ischemic myocardium without reducing the performance of the heart as a pump. Hypothermia may be useful as a therapeutic adjunct to myocardial revascularization or pharmacologic interventions.

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PubMedDate not supplied

Contrast-enhanced magnetic resonance angiography of carotid arterial wall in pigs.

This study was designed to investigate the effects of contrast agents on MR images of balloon-injured carotid arteries containing atherosclerotic-like lesions. We have evaluated an intravascular contrast agent, MS-325 (METASYN INC., Cambridge, MA) and an extravascular contrast agent, Optimark, (Mallinckrodt Medical Inc., St. Louis, MO) on MR angiograms obtained 4 weeks after balloon hyperinflation-induced injury of the left common carotid artery in 12 hypercholesterolemic minipigs. High in-plane resolution (.8 x .4 mm2), thin slice (1 mm) time-of-flight gradient echo sequences were used to acquire the MR angiographic images. Vascular lumen definition was compared before and after a single bolus intravenous injection of a contrast agent. Digital subtraction angiograms were obtained from all pigs after MR imaging. High grade stenosis developed in 1 of the 12 pigs and five pigs had complete occlusion of the injured vessel. The remaining pigs exhibited essentially no visible stenoses as assessed either by MR angiography or digital subtraction angiography. The vessel walls of the stenosed and occluded vessels were visible after the injection of either intravascular or extravascular contrast agent. Histologic analyses showed well developed neovascularization in the neointima or occlusive thrombosis. We conclude that the observed contrast-enhanced vessel wall is caused by an increased vascular supply associated with thrombosis and neointimal thickening that leads to an accumulation of contrast agent in the abnormal vessel walls after the injection of the T1-shortening paramagnetic contrast agent.

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PubMedDate not supplied

Intravascular contrast agent improves magnetic resonance angiography of carotid arteries in minipigs.

This study was designed to optimize three-dimensional (3D) time-of-flight (TOF) magnetic resonance angiography (MRA) sequences and to determine whether contrast-enhanced MRA could improve the accuracy of lumen definition in stenosed carotid arteries of minipigs. 3D TOF MRA was acquired with use of either an intravascular (n = 13) and/or an extravascular contrast agent (n = 5) administrated at 2 to 4 weeks after balloon-induced injury to a carotid artery in 16 minipigs. Vascular contrast, defined as signal intensity differences between blood vessels and muscle normalized to the signal intensity of muscle, was compared before and after the injection of each contrast agent and between the two agents. Different vascular patencies were observed among the animals, including completely occluded vessels (n = 5), stenotic vessels (n = 3), and vessels with no visible stenosis (n = 8). Superior vascular contrast improvement was observed for small arteries and veins and for large veins with the intravascular contrast agent when compared with the extravascular contrast agent. In addition, preliminary studies in two of the animals showed a good correlation for the extent of luminal stenosis defined by digital subtraction angiography compared with MRA obtained after administration of the intravascular contrast agent (R2 = .71, with a slope of .96 +/- .04 by a linear regression analysis). We concluded that use of an intravascular contrast agent optimizes 3D TOF MRA and may improve its accuracy compared with digital subtraction angiography.

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