Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study Group. Prevention of cardiovascular events and death with pravastatin in patients with coronary heart disease and a broad range of initial cholesterol levels

The health care burden of unstable angina

Worldwide, UA represents a significant allocation of resources. UA represents a syndrome where not only do many therapies exist, but considerable clinical trial evidence has accumulated. Universal application of effective practice patterns is warranted if we are to successfully reduce the burden of UA. Economic analyses cannot resolve many of the underlying societal issues that affect decision making. Often, the acceptability of an economic burden is dependent on the willingness of both individuals and society to pay. In an interesting study, Chestnut et al evaluated the willingness of 50 patients to pay for avoiding a worsening of their angina symptoms. On average, the patients were willing to pay between $210 and $499 to avoid four to eight additional angina episodes each month. The "rule of rescue" suggests that society is often willing to pay large sums of money to save those in extreme need, such as the 55-year-old man rushed to the emergency department clutching his chest. Only recently has attention been paid to how much this disease entity costs us. Whereas the 1980s and 1990s saw a focus on costs, the next century will increasingly focus on value--obtaining the best health outcome for the dollars spent. Debate has shifted, at least in part, from purely financial costs to medical effectiveness and outcomes management. Continuing assessments of value of interventions and application of evidence based-management strategies permit rational selection of therapy and allow us best to bear the burden of UA.

Evaluating the chest pain patient. Scope of the problem

With an understanding of the pathophysiology of ACS and an increasing number of early therapeutic options, there has been a shift in focus from ruling-out MI to identifying and stratifying risk in all patients with potential ACS. The presenting symptoms and ECG still remain the cornerstone of immediate diagnosis and triage. Through the application of new technologies, such as the cardiac troponins, and a reassessment of techniques, such as perfusion imaging and echocardiography, the clinician has an increasing selection of methods to rapidly assess chest pain of potential ischemic etiology. Coinciding with the evaluation of technology has been the development of the concept of the CPU and associated rapid diagnostic protocols. These protocols, whether they utilize the assistance of mathematic predictive instruments or represent simple triage schemes, form the backbone of a system to improve the care of patients with ACS in the current milieu of cost containment.

[Regulation of endothelial NO production by Rho GTPase]

Endothelial-derived nitric oxide (NO) is an important mediator of vascular function. Clinical studies indicate that HMG-CoA reductase inhibitors (statins) improve endothelial function and reduce the incidence of stroke and myocardial infarction. Treatment of human endothelial cells with statins increased the expression of endothelial NO synthase (eNOS) protein and mRNA expression. Statins increased eNOS mRNA half-life but did not change eNOS gene transcription. Inhibition of mevalonate synthesis by statins not only blocks the formation of cholesterol but also of isoprenoids. The upregulation of eNOS expression by statins was independent of cholesterol but mediated via the inhibition of the isoprenoid geranylgeraniol, whereas farnesiol had no effect on eNOS. Immunoblot analyses, (35S)-GTP gamma S-binding assays and transfection studies revealed that statins upregulate eNOS expression by blocking the geranylgeranylation of the GTPase Rho which is necessary for its membrane-associated activity. Studies with mice showed, that statin treatment upregulates eNOS expression and function independent of serum cholesterol levels. Prophylactic treatment with statins augmented cerebral blood flow and reduced cerebral infarcts in normocholesterolemic mice. These effects of statins were completely absent in eNOS-deficient mice indicating that enhanced eNOS activity by statins is the predominant mechanism by which these agents protect against cerebral injury. Our results suggest that statins provide a novel prophylactic treatment strategy for increasing blood flow and reducing brain injury during cerebral ischemia. Upregulation of eNOS by inhibiting Rho may provide a new pharmacologic target for the treatment of arteriosclerosis, pulmonary hypertension, and heart failure.

Current therapies for secondary prevention after myocardial infarction

Compelling evidence from clinical trials confirms the benefits of secondary prevention for patients with known coronary disease. Preventive therapies initiated after myocardial infarction can extend overall survival, reduce subsequent myocardial infarction, decrease the need for revascularization, and improve quality of life. All patients with atherosclerotic cardiovascular disease should be considered for lipid lowering therapy, antiplatelet agents, beta-blockers, and control of hypertension. Long-term therapy with angiotensin-converting enzyme inhibitors should be continued in patients with systolic dysfunction. Hormone replacement therapy has not been shown to benefit postmenopausal women when initiated after myocardial infarction. Smoking cessation, weight control, exercise, and appropriate diet represent important behavioral modifications.

[Therapy with CSE inhibitors--more than lipid lowering?]

An elevated plasma cholesterol concentration is an established risk factor for coronary heart disease. Dietary and drug interventions with fibrate, nicotinic acid and colestyramine have resulted in a decreased rate of major coronary events but failed to decrease mortality. Studies using the more potent lipid lowering statins have shown remarkable results in primary (WOSCOPS, AFCAPS, TexCAPS) and secondary prevention (4S, CARE, LIPID). The use of these drugs reduced the risk for coronary events as well as the need for interventions. Furthermore, improvement of angina has been shown in several studies. In high-risk patients coronary heart disease associated mortality and overall mortality was reduced. Lowering of cholesterol was shown to be effective in women, older people and diabetics. Lipid lowering improves prognosis after heart transplant and could be an alternative to PTCA. Furthermore it was also shown that cholesterol lowering reduces the incidence of stroke. New mechanisms are discussed to explain the rapid onset of clinical improvement. Among these are: influences on inflammatory processes in the plaque, on vascular smooth muscle activity, on coagulation and on endothelial dysfunction.

[Prevention of coronary heart disease--"evidence-based medicine" of antilipemic therapy]

A considerable number of large scale clinical trials provide clear evidence that cholesterol lowering is one of the most important risk-reduction strategies for secondary and primary prevention of coronary artery disease. Unlike the older studies with fibrates, the most recent trials of cholesterol-lowering therapies with the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have clearly shown that their use can reduce coronary artery disease and total mortality as well as the need for expensive hospitalization and revascularization procedures. Studies such as the Scandinavian Simvastatin Survival Study (4S), the West of Scotland Coronary Prevention Study (WOS), the Cholesterol and Recurrent Events (CARE) trial and most recently the Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) as well as numerous other investigations, have established that decreasing elevated levels of low-density lipoprotein (LDL) cholesterol will result in a reduction in risk of coronary artery disease. In addition, HMG-CoA reductase inhibition reduces the risk for cerebral ischemia. Recent data indicate that less than half of patients with coronary artery disease receive cholesterol-lowering therapy, and few meet the LDL-cholesterol goal. Therefore clinicians treating coronary artery disease need to emphasize secondary prevention and recognize the key role of cholesterol-lowering therapy. The challenge for clinicians is to apply the important lessons learned from these clinical trials to an "evidence-based" patient care.

A role for reduced coenzyme Q in atherosclerosis?

Substantial evidence implicates oxidative modification of low density lipoprotein (LDL) as an important event contributing to atherogenesis. As a result, the elucidation of the molecular mechanisms by which LDL is oxidized and how such oxidation is prevented by antioxidants has been a significant research focus. Studies on the antioxidation of LDL lipids have focused primarily on alpha-tocopherol (alpha-TOH), biologically and chemically the most active form of vitamin E and quantitatively the major lipid-soluble antioxidant in extracts prepared from human LDL. In addition to alpha-TOH, plasma LDL also contains low levels of ubiquinol-10 (CoQ10H2; the reduced form of coenzyme Q10). Recent studies have shown that in oxidizing plasma lipoproteins alpha-TOH can exhibit anti- or pro-oxidant activities for the lipoprotein's lipids exposed to a vast array of oxidants. This article reviews the molecular action of alpha-TOH in LDL undergoing "mild" radical-initiated lipid peroxidation, and discusses how small levels of CoQ10H2 can represent an efficient antioxidant defence for lipoprotein lipids. We also comment on the levels alpha-TOH, CoQ10H2 and lipid oxidation products in the intima of patients with coronary artery disease and report on preliminary studies examining the effect of coenzyme Q10 supplementation on atherogenesis in apolipoprotein E knockout mice.

Effects of early captopril administration after thrombolysis on regional wall motion in relation to infarct artery blood flow

OBJECTIVES

To determine whether early administration of captopril lessens infarct zone regional wall motion abnormalities when infarct artery blood flow is abnormal.

BACKGROUND

The interaction between angiotensin-converting enzyme (ACE) inhibitor therapy, ventricular function and infarct artery blood flow has not been well described.

METHODS

A total of 493 patients aged < or = 75 years with first infarctions, presenting within 4 h of symptom onset, were randomized to receive 6.25 mg captopril, increasing to 50 mg t.d.s. or a matching placebo 2.1+/-0.4 h after commencing intravenous streptokinase (1.5 x 10(6) U over 30 to 60 min). Trial therapy was stopped 48 h prior to angiography at 3 weeks, to determine regional wall motion and infarct artery flow.

RESULTS

There were no differences in ejection fractions or end-systolic volumes between patients randomized to receive captopril and those randomized to receive a placebo. Among patients with anterior infarction (n = 216), randomization to captopril resulted in fewer hypokinetic chords (40+/-13; vs. 44+/-13; p=0.028) and a trend toward fewer chords >2 SD below normal (26+/-17 vs. 30+/-17; p=0.052) in the infarct zone. In patients randomized to receive captopril who had anterior infarction and Thrombolysis in Myocardial Infarction (TIMI) 0-2, flow there were fewer hypokinetic chords (44+/-12 vs. 50+/-9; p=0.043) and a trend toward fewer chords >2 SD below normal (33+/-15 vs. 39+/-13; p=0.057). Patients receiving captopril who had anterior infarction and corrected TIMI frame counts > 27 had fewer hypokinetic chords (42+/-13 vs. 46+/-12; p=0.015) and fewer chords >2 SD below normal (27+/-17 vs. 32+/-17; p= 0.047). Captopril had no effect in patients with inferior infarction. There were 20 late cardiac deaths (median follow-up 4 years) in the captopril group and 35 in the placebo group (p=0.036).

CONCLUSIONS

Randomization to receive captopril 2 h after streptokinase improved regional wall motion at 3 weeks. The greatest benefit was seen in patients with anterior infarction particularly when infarct artery blood flow is reduced.