Biomedical subjects
Publications and source records attributed to Luther T Clark.
Direct thrombin inhibitors (DTI) are emerging as alternative anticoagulants to unfractionated heparin and indirect thrombin inhibitors in patients undergoing percutaneous coronary intervention (PCI). We review the pharmacological properties of these newer antithrombotic agents and evaluate the clinical data demonstrating their use in patients undergoing PCI.
The Adult Treatment Panel III (ATP III) of the National Cholesterol Education Program issued an evidence-based set of guidelines on cholesterol management in 2001. Since the publication of ATP III, 5 major clinical trials of statin therapy with clinical end points have been published. These trials addressed issues that were not examined in previous clinical trials of cholesterol-lowering therapy. The present document reviews the results of these recent trials and assesses their implications for cholesterol management. Therapeutic lifestyle changes (TLC) remain an essential modality in clinical management. The trials confirm the benefit of cholesterol-lowering therapy in high-risk patients and support the ATP III treatment goal of low-density lipoprotein cholesterol (LDL-C) <100 mg/dL. They support the inclusion of patients with diabetes in the high-risk category and confirm the benefits of LDL-lowering therapy in these patients. They further confirm that older persons benefit from therapeutic lowering of LDL-C. The major recommendations for modifications to footnote the ATP III treatment algorithm are the following. In high-risk persons, the recommended LDL-C goal is <100 mg/dL, but when risk is very high, an LDL-C goal of <70 mg/dL is a therapeutic option, ie, a reasonable clinical strategy, on the basis of available clinical trial evidence. This therapeutic option extends also to patients at very high risk who have a baseline LDL-C < 100 mg/dL. Moreover, when a high-risk patient has high triglycerides or low high-density lipoprotein cholesterol (HDL-C), consideration can be given to combining a fibrate or nicotinic acid with an LDL-lowering drug. For moderately high-risk persons (2+ risk factors and 10-year risk 10% to 20%), the recommended LDL-C goal is <130 mg/dL, but an LDL-C goal <100 mg/dL is a therapeutic option on the basis of recent trial evidence. The latter option extends also to moderately high-risk persons with a baseline LDL-C of 100 to 129 mg/dL. When LDL-lowering drug therapy is employed in high-risk or moderately high-risk persons, it is advised that intensity of therapy be sufficient to achieve at least a 30% to 40% reduction in LDL-C levels. Moreover, any person at high risk or moderately high risk who has lifestyle-related risk factors (eg, obesity, physical inactivity, elevated triglycerides, low HDL-C, or metabolic syndrome) is a candidate for TLC to modify these risk factors regardless of LDL-C level. Finally, for people in lower-risk categories, recent clinical trials do not modify the goals and cutpoints of therapy.
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The Adult Treatment Panel III (ATP III) of the National Cholesterol Education Program issued an evidence-based set of guidelines on cholesterol management in 2001. Since the publication of ATP III, 5 major clinical trials of statin therapy with clinical end points have been published. These trials addressed issues that were not examined in previous clinical trials of cholesterol-lowering therapy. The present document reviews the results of these recent trials and assesses their implications for cholesterol management. Therapeutic lifestyle changes (TLC) remain an essential modality in clinical management. The trials confirm the benefit of cholesterol-lowering therapy in high-risk patients and support the ATP III treatment goal of low-density lipoprotein cholesterol (LDL-C) <100 mg/dL. They support the inclusion of patients with diabetes in the high-risk category and confirm the benefits of LDL-lowering therapy in these patients. They further confirm that older persons benefit from therapeutic lowering of LDL-C. The major recommendations for modifications to footnote the ATP III treatment algorithm are the following. In high-risk persons, the recommended LDL-C goal is <100 mg/dL, but when risk is very high, an LDL-C goal of <70 mg/dL is a therapeutic option, ie, a reasonable clinical strategy, on the basis of available clinical trial evidence. This therapeutic option extends also to patients at very high risk who have a baseline LDL-C <100 mg/dL. Moreover, when a high-risk patient has high triglycerides or low high-density lipoprotein cholesterol (HDL-C), consideration can be given to combining a fibrate or nicotinic acid with an LDL-lowering drug. For moderately high-risk persons (2+ risk factors and 10-year risk 10% to 20%), the recommended LDL-C goal is <130 mg/dL, but an LDL-C goal <100 mg/dL is a therapeutic option on the basis of recent trial evidence. The latter option extends also to moderately high-risk persons with a baseline LDL-C of 100 to 129 mg/dL. When LDL-lowering drug therapy is employed in high-risk or moderately high-risk persons, it is advised that intensity of therapy be sufficient to achieve at least a 30% to 40% reduction in LDL-C levels. Moreover, any person at high risk or moderately high risk who has lifestyle-related risk factors (eg, obesity, physical inactivity, elevated triglycerides, low HDL-C, or metabolic syndrome) is a candidate for TLC to modify these risk factors regardless of LDL-C level. Finally, for people in lower-risk categories, recent clinical trials do not modify the goals and cutpoints of therapy.
We sought to determine the role of an abnormal ankle-brachial index (ABI) in an African-American population with suspected coronary artery disease (CAD) referred for diagnostic coronary angiography. In this population, an ABI < or =0.90 predicted the presence of > or =3-vessel or left main CAD with a sensitivity of 85% and specificity of 77%. However, a normal ABI did not predict absence of 1- or 2-vessel CAD. These results suggest that in this population, the ABI can be used to increase the pretest probability of severe CAD.
The efficacy of statins in lowering low-density lipoprotein cholesterol (LDL-C) and reducing coronary heart disease risk is well established; however, recent evidence suggests that more aggressive lipid management, even beyond achievement of currently recommended LDL-C goals, may provide additional clinical benefits. A novel approach to the aggressive lowering of LDL-C is the combination of statins with agents that affect different aspects of cholesterol metabolism. Because absorption of cholesterol is an important contributor to cholesterol balance, the simultaneous inhibition of cholesterol absorption and cholesterol synthesis is an attractive approach to achieving greater LDL-C reductions. In clinical trials, the combination of the cholesterol absorption inhibitor ezetimibe with a statin resulted in greater improvements in lipids than statin monotherapy and allowed a greater percentage of patients to achieve treatment goals. In addition, this combination may offer benefits through reduction of phytosterols, chylomicron remnants, and C-reactive protein. Several ongoing trials are evaluating whether the benefit of simultaneously blocking cholesterol synthesis and intestinal cholesterol absorption translates into better clinical outcomes.
The Adult Treatment Panel III (ATP III) of the National Cholesterol Education Program issued an evidence-based set of guidelines on cholesterol management in 2001. Since the publication of ATP III, 5 major clinical trials of statin therapy with clinical end points have been published. These trials addressed issues that were not examined in previous clinical trials of cholesterol-lowering therapy. The present document reviews the results of these recent trials and assesses their implications for cholesterol management. Therapeutic lifestyle changes (TLC) remain an essential modality in clinical management. The trials confirm the benefit of cholesterol-lowering therapy in high-risk patients and support the ATP III treatment goal of low-density lipoprotein cholesterol (LDL-C) <100 mg/dL. They support the inclusion of patients with diabetes in the high-risk category and confirm the benefits of LDL-lowering therapy in these patients. They further confirm that older persons benefit from therapeutic lowering of LDL-C. The major recommendations for modifications to footnote the ATP III treatment algorithm are the following. In high-risk persons, the recommended LDL-C goal is <100 mg/dL, but when risk is very high, an LDL-C goal of <70 mg/dL is a therapeutic option, ie, a reasonable clinical strategy, on the basis of available clinical trial evidence. This therapeutic option extends also to patients at very high risk who have a baseline LDL-C <100 mg/dL. Moreover, when a high-risk patient has high triglycerides or low high-density lipoprotein cholesterol (HDL-C), consideration can be given to combining a fibrate or nicotinic acid with an LDL-lowering drug. For moderately high-risk persons (2+ risk factors and 10-year risk 10% to 20%), the recommended LDL-C goal is <130 mg/dL, but an LDL-C goal <100 mg/dL is a therapeutic option on the basis of recent trial evidence. The latter option extends also to moderately high-risk persons with a baseline LDL-C of 100 to 129 mg/dL. When LDL-lowering drug therapy is employed in high-risk or moderately high-risk persons, it is advised that intensity of therapy be sufficient to achieve at least a 30% to 40% reduction in LDL-C levels. Moreover, any person at high risk or moderately high risk who has lifestyle-related risk factors (eg, obesity, physical inactivity, elevated triglycerides, low HDL-C, or metabolic syndrome) is a candidate for TLC to modify these risk factors regardless of LDL-C level. Finally, for people in lower-risk categories, recent clinical trials do not modify the goals and cutpoints of therapy.
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The metabolic syndrome and type 2 diabetes mellitus are increasingly associated with cardiovascular disease morbidity and mortality in African Americans. African Americans are specifically prone to the negative effects of hypertension and risk factor clustering associated with the metabolic syndrome and diabetes. Data demonstrate a decrease in cardiovascular events in diabetic patients with secondary prevention and, most recently, primary prevention with lipid-lowering therapy. African Americans should benefit from intense risk factor control, including antihypertensive therapy and lipid lowering, to prevent cardiovascular disease. Appropriate lifestyle modification programs, glucose control, and cardiovascular risk reduction therapy will reduce the excessive morbidity and mortality in this population.
BACKGROUND: Coronary heart disease (CHD), the result of coronary atherosclerosis, is the largest single killer of Americans. Central to the pathogenesis of atherosclerosis are the deposition and retention of cholesterol in the arterial walls. Lipid modification, therefore, is key to CHD prevention. METHODS: Data from trials evaluating the safety and efficacy of several pharmacologic agents for dyslipidemia were thoroughly reviewed. RESULTS: Agents such as bile acid sequestrants, fibric acids, and nicotinic acid have a role in treating dyslipidemia. However, statins are the safest and most effective of the lipid-modifying drugs, reducing the incidence of CHD by as much as 21% to 43%. Despite the overall safety and efficacy of these agents, many patients undergoing statin therapy fail to achieve the treatment goals specified in the National Cholesterol Education Program Adult Treatment Panel III guidelines, often because of suboptimal use, tolerability problems, or lack of compliance. Although adverse effects of statins are generally mild and transient, more serious adverse effects, including myotoxicity, liver toxicity, and rhabdomyolysis, are still possible with statin monotherapy and are more common in patients receiving concomitant therapy with other drugs metabolized by the cytochrome P-450 enzyme system. CONCLUSIONS: Because of the overall safety and efficacy of the statins, more patients with or at risk for CHD should be receiving aggressive therapy to lower low-density lipoprotein cholesterol levels and reduce CHD risk.
The Metabolic Syndrome represents a specific clustering of cardiovascular risk factors. One of several recently proposed definitions encompasses 3 or more of the following 5 abnormalities: waist circumference > 102 cm in men or > 88 cm in women, serum triglyceride level > or = 150 mg/dL, high-density lipoprotein cholesterol level < 40 mg/dL in men or < 50 mg/dL in women, blood pressure (BP) > or = 130/> or = 85 mm Hg and serum glucose > or = 110 mg/dL. The diagnosis of Metabolic Syndrome allows early recognition of an increased risk of cardiovascular disease. African Americans have the highest coronary heart disease mortality of any ethnic group in the United States. African-American women and Hispanic men and women have the highest prevalence of the Metabolic Syndrome. This phenomenon is attributable mainly to the disproportionate occurrence of elevated BP, obesity, and diabetes in African Americans, and the high prevalence of obesity and diabetes in Hispanics. Management of the Metabolic Syndrome consists primarily of modification or reversal of the root causes and direct therapy of the risk factors. The first strategy involves weight reduction and increased physical activity, both of which can improve all components of the syndrome. The second strategy often involves drug treatment of the individual risk factors to further improve BP, lipids, and glucose thereby decreasing the risk of cardiovascular disease. This comprehensive review is provided as part of the educational activities of the African-American Lipid and Cardiovascular Council (AALCC).
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BACKGROUND: African Americans have greater precordial QRS voltages than whites, with concomitant higher prevalences of electrocardiographic (ECG) left ventricular hypertrophy (LVH) and lower specificity of ECG LVH criteria for the identification of anatomic hypertrophy. However, the high mortality associated with LVH in African American patients makes more accurate ECG detection of LVH in these patients a clinical priority. METHODS: Electrocardiograms and echocardiograms were obtained at study baseline in 120 African American and 751 white hypertensive patients enrolled in the Losartan Intervention For Endpoint (LIFE) echocardiographic substudy. The ECG LVH was determined using Sokolow-Lyon, 12-lead sum, and Cornell voltage criteria. Echocardiographic LVH was defined by LV mass indexed to height(2.7) >46.7 g/m(2.7) in women and >49.1 g/m(2.7) in men. RESULTS: After adjusting for ethnic differences in LV mass, body mass index, sex, and prevalence of diabetes, mean Sokolow-Lyon and 12-lead sum of voltage were significantly higher, but Cornell voltage was lower, in African Americans than in whites. As a consequence of these differences, when identical partition values were used in both ethnic groups, Sokolow-Lyon and 12-lead voltage criteria had lower specificity in African Americans than whites (44% v 69%, P = .007 and 44% v 59%, P = .10) but had greater sensitivity in African Americans (51% v 27%, P < .001 and 62% v 45%, P = .003). In contrast, Cornell voltage specificity was higher (78% v 62%, P = .09) but sensitivity was slightly lower (49% v 57%, P = 0.16) in African Americans. However, when overall test performance was compared using receiver operating curve analyses that were independent of partition value selection, ethnic differences in test performance disappeared, with no differences in accuracy of any of the ECG voltage criteria for the identification of LVH between African American and white hypertensive individuals. CONCLUSIONS: When standard, non-ethnicity-specific thresholds for the identification of LVH are used, Sokolow-Lyon and 12-lead voltage overestimate and Cornell voltage underestimates the presence and severity of LVH in African American relative to white individuals. However, these apparent ethnic differences in test performance disappear when ethnic differences in the distribution of ECG LVH criteria are taken into account. These findings demonstrate that ethnicity-specific ECG criteria can equalize detection of anatomic LVH in African American and white patients.
Low-molecular-weight heparins and direct thrombin inhibitors are emerging as alternative anticoagulants to unfractionated heparin in patients undergoing percutaneous coronary intervention (PCI). This paper reviews the pharmacologic properties of these newer antithrombotic agents and evaluates the clinical data demonstrating their use in patients undergoing PCI.
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