Cardiology

We evaluated the potential benefit of using myocardial perfusion scintigraphy as a gatekeeping technique prior to performing coronary angiography and revascularization procedures in patients with stable angina pectoris. Results showed that about half of all catheterizations and almost one fifth of coronary revascularizations could be avoided, assuming that only patients with reversible (stress-induced) myocardial ischemia and a minority of patients with "fixed" perfusion defects (present both at rest and during stress) would benefit from coronary revascularization.

The study by Høilund-Carlsen and Johansen evaluates the benefits of using myocardial perfusion scintigraphy (MPS) in a new way—as a gatekeeping technique for further invasive diagnostic and therapeutic procedures among patients with stable angina pectoris.

In a case-control substudy of the Veterans Affairs High-Density Lipoprotein Intervention Trial, therapy with gemfibrozil was shown to reduce the total number of low-density lipoprotein (LDL) particles, especially small, more oxidizable LDL particles, which was associated with a reduced risk of coronary heart disease (CHD) events. Gemfibrozil also increased small-sized high-density lipoprotein particle numbers, which also correlated with a decrease in CHD events. Notably, these changes in particle numbers were not associated with significant changes in lipoprotein cholesterol concentrations, which current guidelines have made the principal target of lipid therapy.

Conventional measurements of cardiac lipoprotein risk include cholesterol, triglyceride, and high-density lipoprotein (HDL) cholesterol levels. Low-density lipoprotein (LDL) cholesterol is estimated from these measurements.

We prospectively studied the relationship between C-reactive protein, obtained within 12 to 24 hours of symptom onset, and long-term risk of death and heart failure in survivors of acute myocardial infarction. The risk of death and heart failure increased progressively with increasing quartiles of C-reactive protein. We found a graded positive relationship between C-reactive protein levels and post-discharge mortality and heart failure.

Biomarkers seem to be proliferating everywhere, with at least 1 "major" new marker appearing each year.

To evaluate whether the early use of statins would reduce cardiovascular events, we conducted a prospective, randomized trial that included 486 patients with acute myocardial infarction and normal total cholesterol levels, of whom 241 patients received statin therapy. The statin group had a lower risk of congestive heart failure and symptomatic myocardial ischemia, which indicates that early treatment with statins reduces recurrent cardiovascular events.

Numerous clinical trials have shown that HMG CoA reductase inhibitor (statin) therapy reduces the risk of myocardial infarction (MI), stroke, and mortality in patients with cardiovascular disease.

The role of combination therapy with an oral anticoagulant and aspirin for patients recovering from an acute coronary syndrome is still being debated. The results of our meta-analysis showed that treatment with aspirin plus warfarin at international normalized ratio values between 2 and 3 significantly reduces the risk of major adverse events compared with aspirin alone but also increases the risk of major bleeding. For every 100 patients receiving combination therapy, approximately 3 major adverse events are prevented and 1 major hemorrhage occurs.

The study by Andreotti and Testa from Rome, Italy, was a retrospective lit erature review and meta-analysis of treatment with aspirin and warfarin (Coumadin) in survivors of acute coronary syndromes.

We performed a meta-analysis of the effect of long-term treatment with antiarrhythmic drugs for the prevention of recurrent atrial fibrillation after conversion to sinus rhythm. We found that several class IA, IC, and III drugs are effective in maintaining sinus rhythm, but virtually all of them increase adverse effects, including proarrhythmia. In addition, class IA drugs are associated with increased mortality. The final risk-benefit ratio of antiarrhythmic drugs on clinically relevant outcomes is still unclear.

Lafuente-Lafuente and colleagues performed a meta-analysis of 44 studies of 11 322 patients in randomized controlled trials of persons with atrial fibrillation who received antiarrhythmic drugs after restoration of sinus rhythm.

Patients who survive an acute coronary syndrome are at much higher risk of a recurrent event within the following month than patients with stable coronary syndromes. Statin therapy lowers the risk of recurrent events for many years but also reduces the risk of another event within the weeks to months following the initial acute coronary syndrome. The mechanisms that contribute to this benefit are likely related to improved endothelial function, decreased vascular inflammation, and reduced prothrombotic factors. Observation studies show an early reduction in mortality with statin therapy started before discharge from the hospital after an acute coronary syndrome.

Using a retrospective observational study design, we assessed whether all angiotensin-converting enzyme (ACE) inhibitors had similar mortality rates after acute myocardial infarction in patients aged 65 years or older. Our results showed that mortality rates for enalapril, fosinopril, captopril, and quinapril were higher than that for ramipril. This suggests that there is no class effect for ACE inhibitors. Further research is needed to confirm the results of our study.

The problem of managing acute myocardial infarction (MI) in elderly patients, especially in those patients with left ventricular dysfunction, has multiple components, not the least of which is to decide which class of agents to use first (angiotensin-converting enzyme [ACE] inhibitors, diuretics, β blockers, etc) and whether to use these agents alone or in combination with 1 or more of the other classes of drugs.

We assessed whether there is a paradoxical increase in cardiovascular events with lower blood pressure values among patients with hypertension and coronary artery disease (CAD) who were enrolled in the International Verapamil-Trandolapril Study (INVEST). The relationship between systolic and diastolic pressure and the risk of primary outcome followed a J-curve pattern, with the relationship being relatively weak for systolic pressure but more significant for diastolic pressure. Our data indicate that excessive lowering of diastolic pressure in hypertensive patients with CAD should be avoided.

The manuscript by Messerli and colleagues, entitled "Dangers of aggressively lowering blood pressure in coronary artery disease," raises a controversial issue with important clinical implications—the J-shaped curve.

We performed a systematic literature review and meta-analysis to evaluate the efficacy of angiotensin-converting enzyme inhibitors in patients with coronary artery disease and normal systolic left ventricular function. Angiotensin- converting enzyme inhibitor use was associated with modest benefits, which included a reduction in cardiovascular mortality, nonfatal myocardial infarction, and revascularization rates.

Angiotensin-converting enzyme (ACE) inhibitors have been shown to be beneficial in the management of multiple cardiovascular disease states.