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Biomedical subjects

J S Vasko

Publications and source records attributed to J S Vasko.

At least 55 records · Page 3Linked to original sources
PubMed1976

Intimal changes in arteriovenous bypass grafts. Effects of varying the angle of implantation at the proximal anastomosis and of producing stenosis in the distal runoff artery.

Autologous arteriovenous bypass grafts were constructed between external iliac arteries in 20 mongrel dogs to determine the development of intimal fibromuscular hyperplasia. Animals received grafts at 55, 90 or 120 degree angles relative to the proximal anastomosis. Five animals with 90 degree angle grafts were also subjected to 80% stenosis in the runoff artery. All grafts showed the development of a fibromuscular tunica intima. Qualitative or quantitative intimal differences were not observed among grafts placed at 90 degree angles, 90 degree angles with runoff artery stenosis, or 120 degree angles. Grafts placed at 55 degree angles relative to the proximal anastomosis developed a consistently thicker fibromuscular layer in the tunica intima when compared to the other groups. These changes which were segmental in nature, occurred in the proximal and distal grafts and over the distal anastomosis.

Animals↗
PubMed1975

Effects of pharmacological myocardial depression on coronary artery collateral formation.

Treatment of angina pectoris falls within two spheres: (1) increasing myocardial blood flow (direct bypass, vasodilators), or (2) reducing oxygen demand (beta blockade, propranolol). If the latter depresses the stimulus for collateralization without improving input, its use in certain forms of coronary disease may require reconsideration. To examine this hypothesis, 25 dogs (four groups) were evaluated by surface mapping, angiographic collateral mapping, and hemodynamic studies including cardiac output, systemic and coronary pressures, coronary flow, and left ventricular end-diastolic pressure, pressure to time (LVdp/dt). Collateralization was induced with ameroid constrictor placement in Groups I, III, and IV. Groups II and III received immediate propranolol treatment (3 to 5 mg. per kilogram per day for 6 weeks); Group IV received delayed treatment (4 weeks after constriction); and Group I received no propranolol (constrictor alone). Collateral formation was depressed significantly in the acutely beta-blockaded dogs (Group III) by surface and angiographic mapping and by hemodynamic evidence of depressed coronary flow and altered coronary retrograde pressures. Alterations in established collaterals (Group IV) were not consistent. These data suggest that pharmacological reduction of myocardial oxygen demand reduces coronary collateralization experimentally, requiring further evaluation of its usage in multivessel coronary disease to the exclusion of direct bypass.

Adrenergic beta-Antagonists↗