Elevation in serum troponin I predicts the benefit of tirofiban.

BACKGROUND: Elevations in serum troponins among patients with acute coronary syndromes have been shown to identify those patients who are at high risk for poor outcome and who accrue larger relative benefits from aggressive antiplatelet and antithrombotic therapies. We studied a group of patients from the PRISM-PLUS trial to explore whether simply using serum troponin I, a serum marker of cardiac injury, could predict benefit of GP IIb/IIIa receptor antagonism with tirofiban. METHODS AND RESULTS: For this study, the subjects consisted of 55 patients receiving the combination therapy of tirofiban/heparin, and 55 receiving heparin alone. The baseline characteristics were similar between the two treatment groups. Serial blood samples were obtained over the first 24-hour period following randomization to study drug, and were analyzed for troponin I (TnI) levels. Among those patients with elevated serum TnI (>0.5 ng/ml), the 30-day event rate for death or myocardial infarction (MI) was reduced from 20.6% among the heparin only group to 3.6% for those treated with the combination of tirofiban/heparin, an absolute risk reduction of 17% and relative risk reduction of 83% (p=0.06). Among the TnI negative patients, the rates of death/MI at 30 days were 9.5% and 11.1% among the combination and heparin treated groups respectively (p=NS). CONCLUSION: Irrespective of high-risk clinical factors, including ST segment depression, these data support the hypothesis that serum troponins identify those who benefit from aggressive antiplatelet therapy with tirofiban.

Blood pressure and inflammation in apparently healthy men.

Inflammation plays an important role in the development of atherosclerosis, but the specific stimuli governing cytokine release in atherogenesis are unknown. We examined the hypothesis that hypertension may increase the risk of atherosclerosis via proinflammatory effects. In a cross-sectional study involving 508 apparently healthy men, we studied the association between blood pressure and baseline plasma concentrations of 2 inflammatory markers, intercellular adhesion molecule-1 (sICAM-1) and interleukin-6 (IL-6). Increase in systolic blood pressure (SBP) (P=0.003), pulse pressure (PP) (P=0.019), and mean arterial pressure (P=0.014) was significantly associated with levels of sICAM-1. All of these measures of blood pressure, as well as diastolic blood pressure (DBP), were significantly associated with levels of IL-6 (all, P

Diabetes and all-cause and coronary heart disease mortality among US male physicians.

BACKGROUND: While diabetes has long been associated with increased risk of coronary heart disease (CHD), the magnitude of risk of diabetes-related CHD is uncertain. OBJECTIVE: To evaluate the impact of diabetes and prior CHD on all-cause and CHD mortality. METHODS: In a prospective cohort study of 91 285 US male physicians aged 40 to 84 years, participants were divided into 4 groups: (1) a reference group of 82 247 men free of both diabetes and CHD (previous myocardial infarction and/or angina) at baseline, (2) 2317 men with a history of diabetes but not CHD, (3) 5906 men with a history of CHD but not diabetes, and (4) 815 men with a history of both diabetes and CHD. Rates of all-cause and CHD mortality were compared in these groups. RESULTS: Over 5 years (49 7952 person-years of follow-up), 3627 deaths from all causes were documented, including 1242 deaths from CHD. Compared with men with no diabetes or CHD, the age-adjusted relative risk of death from any cause was 2.3 (95% confidence interval [CI], 2.0-2.6) among men with diabetes and without CHD, 2.2 (95% CI, 2.0-2.4) among men with CHD and without diabetes, and 4.7 (95% CI, 4.0-5.4) among men with both diabetes and CHD. The relative risk of CHD death was 3.3 (95% CI, 2.6-4.1) among men with diabetes and without CHD, 5.6 (95% CI, 4.9-6.3) among men with CHD and without diabetes, and 12.0 (95% CI, 9.9-14.6) among men with both diabetes and CHD. Multivariate adjustment for body mass index, smoking status, alcohol intake, and physical activity as well as stratification by these variables did not materially alter these associations. CONCLUSIONS: These prospective data indicate that diabetes is associated with a substantial increase in all-cause and CHD mortality. For all-cause mortality, the magnitude of excess risk conferred by diabetes is similar to that conferred by a history of CHD; for mortality from CHD, a history of CHD is a more potent predictor of death. The presence of both diabetes and CHD, however, identifies a particularly high-risk group.

Triggering of sudden death from cardiac causes by vigorous exertion.

BACKGROUND: Retrospective and cross-sectional data suggest that vigorous exertion can trigger cardiac arrest or sudden death and that habitual exercise may diminish this risk. However, the role of physical activity in precipitating or preventing sudden death has not been assessed prospectively in a large number of subjects. METHODS: We used a prospective, nested case-crossover design within the Physicians' Health Study to compare the risk of sudden death during and up to 30 minutes after an episode of vigorous exertion with that during periods of lighter exertion or none. We then evaluated whether habitual vigorous exercise modified the risk of sudden death that was associated with vigorous exertion. In addition, the relation of vigorous exercise to the overall risk of sudden death and nonsudden death from coronary heart disease was assessed. RESULTS: During 12 years of follow-up, 122 sudden deaths were confirmed among the 21,481 male physicians who were initially free of self-reported cardiovascular disease and who provided information on their habitual level of exercise at base line. The relative risk of-sudden death during and up to 30 minutes after vigorous exertion was 16.9 (95 percent confidence interval, 10.5 to 27.0; P<0.001). However, the absolute risk of sudden death during any particular episode of vigorous exertion was extremely low (1 sudden death per 1.51 million episodes of exertion). Habitual vigorous exercise attenuated the relative risk of sudden death that was associated with an episode of vigorous exertion (P value for trend=0.006). The base-line level of exercise was not associated with the overall risk of subsequent sudden death. CONCLUSIONS: These prospective data from a study of U.S. male physicians suggest that habitual vigorous exercise diminishes the risk of sudden death during vigorous exertion.

Pulse pressure and mortality in older people.

BACKGROUND: In older people, observational data are unclear concerning the relationships of systolic and diastolic blood pressure with cardiovascular and total mortality. We examined which combinations of systolic, diastolic, pulse, and mean arterial pressure best predict total and cardiovascular mortality in older adults. METHODS: In 1981, the National Institute on Aging initiated its population-based Established Populations for Epidemiologic Studies of the Elderly in 3 communities. At baseline, 9431 participants, aged 65 to 102 years, had blood pressure measurements, along with measures of medical history, use of medications, disability, and physical function. During an average follow-up of 10. 6 years among survivors, 4528 participants died, 2304 of cardiovascular causes. RESULTS: In age- and sex-adjusted survival analyses, the lowest overall death rate occurred among those with systolic pressure less than 130 mm Hg and diastolic pressure 80 to 89 mm Hg; relative to this group, the highest death rate occurred in those with systolic pressure of 160 mm Hg or more and diastolic pressure less than 70 mm Hg (relative risk, 1.90; 95% confidence interval, 1.47-2.46). Both low diastolic pressure and elevated systolic pressure independently predicted increases in cardiovascular (P<.001) and total (P<.001) mortality. Pulse pressure correlated strongly with systolic pressure (R = 0.82) but was a slightly stronger predictor of both cardiovascular and total mortality. In a model containing pulse pressure and other potentially confounding variables, diastolic pressure (P =.88) and mean arterial pressure (P =.11) had no significant association with mortality. CONCLUSIONS: Pulse pressure appears to be the best single measure of blood pressure in predicting mortality in older people and helps explain apparently discrepant results for low diastolic blood pressure.

Effects of tirofiban plus heparin versus heparin alone on troponin I levels in patients with acute coronary syndromes.

Elevated serum troponins following an acute coronary syndrome (ACS) predict a poor clinical outcome. Glycoprotein (GP) IIb/IIIa inhibitors reduce adverse clinical outcomes in patients with ACS, although their effect on serum troponin I (TnI) in this setting has not been described. We therefore studied the effects of the GP IIb/IIIa inhibitor tirofiban on serum TnI levels in a group of patients in the Platelet Inhibition in Ischemic Syndrome Management in Patients Limited by Unstable Signs and Symptoms trial. Serial blood samples were obtained in 53 patients receiving the combination therapy of tirofiban/heparin and in 52 receiving heparin alone, and were analyzed for baseline, peak, and mean concentrations of TnI. Baseline TnI levels were not different between the combination therapy and heparin-only groups (1.6 +/- 3.0 vs 3.1 +/- 6.7 ng/ml, p = 0.15). The peak TnI level was significantly lower in the combination therapy group than in the heparin group (5.2 +/- 8.3 vs 15.5 +/- 29.1 ng/ml, p = 0.017), and mean levels over the initial 24-hour period were also significantly lower in the combination therapy group (3.2 +/- 5.0 vs 8.5 +/- 14.8 ng/ml, p = 0.016). In univariate analysis, combination therapy was associated with lower TnI levels, whereas in a multivariate model, the lower peak and mean TnI levels as a consequence of tirofiban/heparin compared with heparin monotherapy remained significant (peak, p = 0.029; mean, p = 0.035). Among patients with negative TnI at baseline, treatment with the combination of tirofiban/heparin compared with heparin monotherapy still resulted in significantly lower peak (2.5 +/- 5.4 vs 14.6 +/- 32.8 ng/ml, p = 0.024) and mean (1.2 +/- 2.6 vs 6.9 +/- 15.8 ng/ml, p = 0.029) TnI levels. In patients with ACS, therapy with the combination of tirofiban and heparin (compared with heparin treatment alone) resulted in lower serum TnI levels, suggesting reduced myocardial injury.

Male pattern baldness and coronary heart disease: the Physicians' Health Study.

OBJECTIVE: To examine the association between male pattern baldness and the risk of coronary heart disease (CHD) events. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study among 22,071 US male physicians aged 40 to 84 years enrolled in the Physicians' Health Study. Of these, 19,112 were free of CHD at baseline and completed a questionnaire at the 11-year follow-up concerning their pattern of hair loss at age 45 years. Response options included no hair loss, frontal baldness only, or frontal baldness with mild, moderate, or severe vertex baldness. MAIN OUTCOME MEASURES: Coronary heart disease events defined as nonfatal myocardial infarction (MI), angina pectoris, and/or coronary revascularization. RESULTS: During 11 years of follow-up, we documented 1446 CHD events in this cohort. Compared with men with no hair loss, those with frontal baldness had an age-adjusted relative risk (RR) of CHD of 1.09 (95% confidence interval [CI], 0.94-1.25), while those with mild, moderate, or severe vertex baldness had RRs of 1.23 (95% CI, 1.05-1.43), 1.32 (95% CI, 1.10-1.59), and 1.36 (95% CI, 1.11-1.67), respectively (P for trend, <.001). Multivariate adjustment for age, parental history of MI, height, body mass index (weight in kilograms divided by the square of the height in meters as a continuous variable), smoking, history of hypertension, diabetes, high cholesterol level, physical activity, and alcohol intake did not materially alter these associations. Results were similar when nonfatal MI, angina, and coronary revascularization were examined separately, and when events were analyzed among men older and younger than 55 years at baseline. Vertex baldness was more strongly associated with CHD risk among men with hypertension (multivariate RR, 1.79; 95% CI, 1.31-2.44) or high cholesterol levels (multivariate RR, 2.78; 95% CI, 1.09-7.12). CONCLUSION: Vertex pattern baldness appears to be a marker for increased risk of CHD events, especially among men with hypertension or high cholesterol levels.

Increased pulse pressure and risk of heart failure in the elderly.

CONTEXT: Arterial stiffness increases with age. Thus, pulse pressure, an index of arterial stiffening, may predict congestive heart failure (CHF) in the elderly. OBJECTIVE: To study prospectively the association between pulse pressure and risk of CHF. DESIGN: Prospective cohort study. SETTING: The community-based East Boston Senior Health Project, East Boston, Mass. PATIENTS: A total of 1621 men and women (mean [SD] age, 77.9 [5.0] years) free of CHF who had blood pressure measurements taken in 1988-1989 and were followed up for 3.8 years. MAIN OUTCOME MEASURE: Incidence of CHF as ascertained by hospital discharge diagnosis (n = 208) and death certificates (n = 13). RESULTS: After controlling for age, sex, mean arterial pressure, history of coronary heart disease, diabetes mellitus, atrial fibrillation, valvular heart disease, and antihypertensive medication use, pulse pressure was an independent predictor of CHF. For each 10-mm Hg elevation in pulse pressure, there was a 14% increase in risk of CHF (95% confidence interval, 1.05-1.24; P = .003). Those in the highest tertile of pulse pressure (>67 mm Hg) had a 55% increased risk of CHF (P=.02) compared with those in the lowest (<54 mm Hg). Pulse pressure was more predictive than systolic blood pressure alone and was independent of diastolic blood pressure. CONCLUSION: Pulse pressure, an easily measurable correlate of pulsatile hemodynamic load, is an independent predictor of risk of CHF in this elderly cohort.

Postmenopausal hormone replacement therapy and cardiovascular disease.

Cardiovascular disease is the leading cause of mortality in postmenopausal women in developed countries. A possible cardioprotective role of hormone replacement therapy (HRT) is suggested by epidemiologic studies of HRT and reduced risk of coronary heart disease, as well as by randomized trials of HRT and lipid subfractions. Estrogen has beneficial effects on the lipid profile, raising high-density lipoprotein cholesterol levels and reducing low-density lipoprotein cholesterol levels each by approximately 10%. Other possible biologic mechanisms include beneficial effects on vascular function, oxidative status, endothelial-dependent vasodilation, intimal hyperplasia and insulin sensitivity. Estrogen's net effects on coagulation and fibrinolysis are less clear. Estrogen replacement therapy is associated with decreased atherosclerosis in several animal models. However, most of the available data on HRT derive from observational studies or small randomized trials assessing biologic intermediates rather than clinical events. Further research, including large-scale randomized clinical trials, are required to evaluate definitively the role of estrogen replacement therapy, especially given uncertainties about the effects of combined estrogen-progestin therapy and the balance of benefits and risk of this common intervention in postmenopausal women.

Degradation of collagen in lung tissue slices exposed to hyperoxia.

Exposure of animals to oxidant gases produces a mild emphysema, and O2-derived free radicals are capable of degrading connective tissues in vitro. It is postulated that degradation of connective tissue by O2-derived free radicals leads to emphysema in these models. To determine whether exposure of lung tissue slices to an oxidant gas results in degradation of collagen and to investigate factors mediating this degradation, we exposed lung tissue slices from normal rats to hyperoxia (95% O2, 5% CO2) and measured hydroxyproline release into the medium. After a 4-h exposure, the hydroxyproline released was 5.3 +/- 0.2 micrograms/g lung tissue (n = 10) in normoxia and 8.1 +/- 0.6 micrograms/g tissue (n = 13) in hyperoxia (p less than 0.05), suggesting degradation of collagen. The addition of 0.1% trypsin to the initial incubation medium caused a synergistic increase in hydroxyproline release from O2-exposed slices: normoxia/trypsin, 46.2 +/- 3.6 micrograms/g tissue (n = 10); hyperoxia/trypsin, 61.4 +/- 3.6 micrograms/g tissue (n = 11) (p less than 0.05). The addition of proteinase inhibitors completely suppressed the O2-induced release of hydroxyproline, suggesting that proteolytic enzymes are involved in hyperoxia-mediated degradation of lung collagen.

Damage and repair of lung connective tissue in rats exposed to toxic levels of oxygen.

We studied damage and repair of lung connective tissue in rats exposed to toxic amounts of oxygen by measuring lung content of collagen and elastin and the number of collagen fragments in lung lavage fluid after exposure to 98% O2 for 60 h. Lung collagen was decreased 17%, and collagen fragments in lavage fluid were increased 4- to 5-fold in O2-exposed rats compared with those in control rats. No biochemical evidence of elastin degradation was found. Mild emphysematous changes and a leftward shift of fluid-filled, pressure-volume curves were induced within 2 wk after recovery from exposure to O2. Administration of the lathyrogen beta-aminopropionitrile worsened the emphysematous lesion produced by hyperoxia, suggesting that replacement of connective tissue during repair limits the extent of emphysema. We conclude that lung collagen is degraded and an emphysematous lesion is produced by relatively short exposure to toxic amounts of oxygen.