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Biomedical subjects

D I Silverman

Publications and source records attributed to D I Silverman.

8 recordsLinked to original sources
PubMed1991

Effects of serum lipid levels on restenosis after coronary angioplasty.

Although the association of serum lipid levels with the risk of atherosclerosis is well-recognized, the relation between these levels and restenosis after coronary angioplasty is uncertain. This study examines 186 patients enrolled in a trial of fish oil for prevention of restenosis. Fasting lipid levels (cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides) were measured before angioplasty, and in 90 patients repeated at 6-month follow-up. Fifty-nine patients (32%) developed clinical restenosis confirmed by angiography. Patients who went on to develop restenosis underwent multivessel angioplasty (p less than 0.05) and were more likely to be on lipid-lowering therapy at baseline (27 vs 13%; p less than 0.05). In addition, they had higher baseline cholesterol/HDL ratios (6.5 +/- 2.2 vs 5.9 +/- 2.0; p less than 0.05) and triglyceride levels (233 +/- 210 vs 183 +/- 112 mg/dl; p less than 0.05). Multiple logistic regression analysis confirmed cholesterol/HDL ratios at baseline (p = 0.021) and follow-up (p = 0.0008) to be independent predictors of risk for restenosis. Using these data, regression lines have been developed that predict risk of restenosis based on type of procedure and on lipid values. These results suggest that serum lipid levels may be associated with the risk of clinical restenosis after coronary angioplasty.

Aged↗
PubMed1991

Comparison of the absorption and effect on platelet function of a single dose of n-3 fatty acids given as fish or fish oil.

To compare their relative absorption and effect on platelet function, concentrated fish oil and tuna were given to 10 subjects in a randomized crossover study. Although plasma enrichment of eicosapentaenoic acid (EPA) from either preparation was similar, relative absorption of EPA from tuna was significantly greater than that from fish oil (46.6 +/- 3.0 mg.L-1.g EPA-1 from tuna compared with 16 +/- 1.0 mg.L-1.g EPA-1 from fish oil, P less than 0.001). Relative absorption of docosahexaenoic acid (DHA) was equivalent (54.0 +/- 9.0 mg.L-1.g DHA-1 from tuna, 56 +/- 9.0 mg.L-1.g DHA-1 from fish oil, NS). Platelet aggregation in response to the endoperoxide analog U46619 was significantly diminished after either preparation but aggregation in response to other agonists, bleeding time, and membrane n-3 (omega-3) fatty acid content were not changed. Thus, n-3 fatty acids are well absorbed after one dose of either tuna or fish oil but EPA absorption appears to be more efficient from tuna. Additionally, a single dose of n-3 fatty acids decreases platelet aggregation by a mechanism not requiring incorporation into platelet membranes.

Absorption↗
PubMed1990

Effects of two types of fish oil supplements on serum lipids and plasma phospholipid fatty acids in coronary artery disease.

Fish oil has consistently been shown to lower triglyceride levels, but its effects on low-density lipoprotein (LDL) cholesterol remain controversial. The current study compares the long-term effects of 2 different fish oil preparations (ethyl ester and triglyceride) versus olive oil in patients with coronary artery disease. Eighty-nine subjects were randomly assigned to receive capsules containing 6 g/day (triglyceride group) or 7 g/day (ethyl ester group) of n-3 fatty acids, or capsules containing 12 g/day of olive oil for 6 months. Mean triglyceride levels decreased by 28% in the ester and 32% in the triglyceride fish oil groups (p less than 0.05 for both). LDL cholesterol levels increased by 3% (difference not significant) in the ester and 12% (p less than 0.05) in the triglyceride fish oil groups; in hypertriglyceridemic subjects the increase was 23% (p less than 0.01) and 14% (difference not significant), respectively. Plasma phospholipid fatty acid analysis showed a fivefold increase in eicosapentaenoic acid levels in both fish oil groups (p less than 0.001), and a long-term decrease in arachidonic acid levels (p less than 0.001). Achieved eicosapentaenoic acid level correlated with the degree of increase in LDL cholesterol (r = 0.38, p less than 0.05). These data suggest that fish oil administration is associated with an increase in LDL cholesterol levels in a diverse group of patients with coronary artery disease; this change appears to be correlated with n-3 fatty acid absorption. The impact of this increase in LDL is unknown, but should be considered as potentially adverse.

Coronary Disease↗
PubMed1990

Routine electrocardiograms after cardiac catheterization. Are they useful?

In order to assess the value of routine electrocardiograms after cardiac catheterization (ECGs), 150 consecutive patients undergoing diagnostic cardiac catheterization were studied prospectively. The physician performing each catheterization was asked to rate his or her clinical index of suspicion that the electrocardiogram would be changed as a result of events during the procedure. Clinical index of suspicion and electrocardiograms were then compared for their ability to predict outcomes. Urgent clinical events within 24 hours of cardiac catheterization were defined as (1) new intensive care unit admission; (2) myocardial infarction; (3) coronary artery bypass graft surgery; (4) percutaneous transluminal coronary angioplasty; or (5) death. Chi square analysis demonstrated that neither ECGs (x2 = 2.12, p greater than 0.1) nor clinical index of suspicion (x2 = 2.43, p greater than 0.1) was better than chance alone in predicting urgent clinical events. The addition of ECGs to positive clinical index of suspicion did not increase the ability to predict urgent clinical events (x2 = 2.38, p greater than 0.1). Both ECGs and clinical index of suspicion were found to be relatively insensitive tests (sensitivity = 29% for ECGs, 43% for clinical index of suspicion). While both tests demonstrated high specificity, (89% for ECGs, 79% for clinical index of suspicion), their predictive value was equally poor (21% for ECGs, 17% for clinical index of suspicion). The addition of ECGs to clinical index of suspicion marginally increased the sensitivity of both tests to 50%. We conclude that routine postcatheterization electrocardiograms are no better at predicting urgent clinical events than clinical observation during catheterization alone, and should be performed only when index of suspicion dictates.

Angioplasty, Balloon, Coronary↗
PubMed1990

Acute pulmonary edema following removal of a spinal orthosis: an unusual complication of a halo vest.

The halo vest is a commonly used spinal orthosis that provides stability to the cervical spine. Known complications include loss of spinal reduction, local pin tract infection, skin breakdown over the scapulae, and, rarely, brachial plexus and cranial nerve palsies. The use of the halo vest has not been associated with significant respiratory compromise. Cardiopulmonary complications associated with halo vests have not been reported. We report a case of pulmonary edema associated with removal of a halo vest in a patient with occult mitral stenosis. We speculate that removal of the orthosis resulted in rapid redistribution of peripheral blood volume sufficient in magnitude to provide the hemodynamic substrate for acute pulmonary edema.

Acute Disease↗
PubMed1989

Randomised trial of fish oil for prevention of restenosis after coronary angioplasty.

To examine the potential role of fish oil supplementation in the prevention of restenosis after coronary angioplasty (PTCA), a randomised double-blind trial was conducted in 204 patients. The treatment group received 6 g/day of n-3 fatty acids, beginning 5.4 (SD 3.2) days before PTCA, and continuing for 6 months; the control group received olive oil placebo. Compliance was assessed by pill count and plasma levels of eicosapentaenoic acid (EPA). Restenosis was identified by symptoms and exercise testing and confirmed by angiography. PTCA was successful in 186 patients (93%). The incidence of angiographic restenosis was 34% in the fish oil group and 23% in the control group (relative risk 1.7, 95% CI 0.9-3.4). The lack of benefit of fish oil was not influenced by length of pretreatment, compliance with study medication, or the concentrations of plasma EPA achieved.

Angioplasty, Balloon↗