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Biomedical subjects

J D Slack

Publications and source records attributed to J D Slack.

At least 55 records · Page 3Linked to original sources
PubMed1985

Late recanalization at the site of failed percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty (PTCA) was performed unsuccessfully, resulting in disruption and near-total closure of the proximal right coronary artery at the site of stenosis following balloon inflation. The artery could not be reopened in the catheterization laboratory despite intracoronary nitroglycerin, sublingual nifedipine, and multiple balloon inflations. Myocardial revascularization surgery was immediately performed with excellent graft flow. No apparent myocardial infarction resulted. Catheterization performed at one year showed normal left ventriculography, total occlusion of the bypass graft, and reopening and normalization of the right coronary artery at the site of PTCA-induced occlusion. Possible mechanisms for this phenomenon and its clinical implications are discussed.

Aged↗
PubMed1985

Quantitative evaluation of inflammation in biopsy specimens from idiopathically failing or irritable hearts: experience in 80 pediatric and adult patients.

The histologic criteria for the diagnosis of myocarditis on an endomyocardial biopsy specimen are troubled by varying institutional criteria and interobserver differences. A comprehensive approach to tissue evaluation including quantitative assessment of mononuclear cell populations enhances the accuracy and the specificity of the morphologic diagnosis. Future efforts to characterize the infiltrating cell lines in inflammatory conditions of the heart will aid in the ultimate refinement of therapeutic efficacy.

Adult↗
PubMed1985

Subacute left main coronary stenosis: an unusual but serious complication of percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty (PTCA) is a proven nonoperative method of direct myocardial revascularization. Acute complications occurring during PTCA center primarily around acute disruption at the site of dilatation, arrhythmias, or vascular problems at the site of guide catheter access. Late complications include restenosis or aneurysm formation at the site of dilatation. Subacute stenosis of the left main coronary artery occurred in three of 440 patients who had PTCA performed between September 1980 and December 1983 and may be an infrequent but potentially critical complication of PTCA. The serious clinical course of patients with left main coronary stenosis requires prompt recognition and intervention.

Adult↗
PubMed1985

Complex coronary angioplasty: a technique for dilatation of bifurcation stenoses.

Bifurcation stenoses have been recognized to be at "high risk" for acute closure during percutaneous transluminal coronary angioplasty. Use of the traditional single balloon technique in such situations often results in acute closure or worsening of the stenosis in the other branch. A technique utilizing simultaneous inflation of two balloons, ("kissing balloon" technique) has been utilized to avoid this complication. A double balloon technique has been developed using sequential inflations rather than simultaneous inflations to preserve the integrity of both branches while avoiding the arterial trauma produced by inflating two balloons in a small artery simultaneously. Twelve of 13 bifurcation stenoses were successfully treated with this sequential inflation double balloon technique. (Primary success rate = 92%).

Angina Pectoris↗
PubMed1981

Acute hemodynamic effects and blood pool kinetics of polystyrene microspheres following intravenous administration.

The acute hemodynamic effect of intravenous administration of polystyrene microspheres was investigated and correlated with their distribution pattern and kinetics. Microspheres of three diameters (3.4, 7.4, and 11.6 micrometer) were administered. The 7.4- and 11.6-micrometer diameter microspheres were filtered by the pulmonary capillary network following intravenous administration, the majority during the first pass. There was no significant hemodynamic effect following administrations of the 7.4- and 11.6-micrometer diameter microspheres in doses as high as 3.0 X 10(9) and 6.1 X 10(8) respectively (total cross-sectional area of 1.3 X 10(11) and 6.4 X 10(10) micrometer2, respectively). Intravenous administration of 3.4-micrometer diameter microspheres produced significant dose-dependent systemic hypotension and depression of myocardial performance at dosages as slow as 1.0 X 10(10) (cross-sectional area of 9.1 X 10(10) micrometer2). These differences in acute hemodynamic effect from the 7.4- and 11.6-micrometer diameter microspheres may be due to the differences in distribution kinetics and fate of the 3.4-micrometer diameter microspheres, which readily pass through the lungs to the spleen. Although elimination of the smaller spheres from the blood during the first 6-8 min was rapid, i.e., t 1/2 = 1.62 and 1.72 min from the venous and arterial blood circulation, respectively, levels of 10(3) spheres/g of blood were present in the circulation for greater than 1 hr. These findings must be considered in the planning of intravenous administration of microspheres as a drug delivery system to target organs.

Animals↗
PubMed1981

Influence of potassium cardioplegia versus ischemic arrest on regional left ventricular diastolic compliance in humans.

To compare the effects of hypothermic ischemic arrest versus hypothermic potassium cardioplegia, regional left ventricular performance was monitored in 20 adult male patients undergoing saphenous vein bypass operation. Twelve patients received ischemic arrest (Group 1), and 8 received potassium cardioplegia (Group 2). Groups 1 and 2 did not differ in left ventricular ejection fraction (0.62 versus 0.60), number of bypassed vessels (3.7 versus 3.4), mean cross-clamp time (75 versus 63 minutes), or mean cardiopulmonary bypass time (182 versus 170 minutes). Before cardiopulmonary bypass was begun, a pair of ultrasonic crystals was secured in the left ventricular anterior myocardium to measure segment motion and a micromanometer-tipped catheter was placed in the left ventricular chamber. All patients received a saphenous vein bypass graft to a vessel supplying the anterior left ventricular wall in the region of the ultrasonic crystals. Comparison of changes in systolic measurements revealed no significant differences between Groups 1 and 2. After saphenous vein bypass grafting, the left ventricular end-diastolic pressure (11.4 to 17.0 mm HG) and modulus of left ventricular segment stiffness (0.37 to 0.67, p less than 0.02) were elevated in Group 1 but no changes were observed in Group 2 (14.0 to 15.6 mm Hg, and 0.16 to 0.24, respectively). Compared with hypothermic ischemic arrest, hypothermic potassium cardioplegia is not associated with an increased left ventricular diastolic stiffness shortly after saphenous vein bypass grafting in humans.

Angina Pectoris↗