Silent ischemia a clinical update: ANSWERS part 3

22 Mar
2011

5. a. men age 35 or over with family history of premature coronary artery disease

b. age 35 or over with two or more major cardiovascular risk factors, (dyslipidemias, hypertension, diabetes mellitus and cigarette smoking).

Of all patients with coronary artery insufficiency, the group of asymptomatic individuals with silent ischemia poses a major challenge in terms of detection and management. The implications of a diagnosis of silent ischemia in a previously “healthy” patient are far-reaching and extend beyond the medical realm into psychologic, emotional and socioeconomic areas.

Screening populations with two or more cardiovascular risk factors (hypertension, diabetes mellitus, dyslipidemia, cigarette smoking) or family history of premature coronary artery disease is recommended in order to maximize the predictive value of noninvasive cardiac testing. To ensure accuracy in judgment, sequential testing with two or more independent tests are performed so that the consequences of coronary artery disease in different areas of myocardial function may be exposed. The most commonly accepted approach to the patient with suspected coronary artery disease is the initial performance of exercise electrocardi­ography. In selected cases, this is followed by thallium perfusion imaging and when indicated radionuclide ventric­ulography. The first tests the electrical manifestations of ischemia, the next the perfusion abnormalities, and the latter the mechanical manifestation of coronary insufficiency. It is rare to find a positive 24-hour ambulatory electrocardio­graphic recording in asymptomatic individuals with silent ischemia who previously had a negative exercise stress test. Noninvasive testing for the detection of coronary artery disease is not necessary in males over 60 or postmenopausal females without additional risk factors. 6. a. in patients with silent ischemia coexisting with the anginal syndrome adequate control of the angina is an index of successful therapy b. treatment of coronary insufficiency should be aimed at decreasing the total ischemia burden d. calcium channel blockers and nitrates are highly effective in the management of silent ischemia. Ischemia is the common pathophysiologic denominator underlying the spectrum of clinical coronary artery disease, but since ischemia can be either silent or painful, and since silent ischemia has emerged as the most common manifes­tation of coronary artery disease and the leading pathway linking major cardiovascular events such as myocardial infarction, arrhythmias and sudden death, there is a growing consensus that treatment should be aimed at the total ischemic burden: the sum of all painful and painless episodes of ischemia. Cialis Jelly

The guidelines for treating patients with silent ischemia should be the same as for those with symptomatic ischemia. The rationale for this approach is the established fact that silent ischemia is seen in patients with angina and the ischemic cascade is common to both painful and painless episodes. Therefore, treatment should be dictated by the causes of angina, the severity and duration of angina, and the coexistence of arrhythmias and transient dyspnea. Beta blockade plus nitrates make up the cornerstone of manage­ment. Beta blockade significantly improves mortality and morbidity in patients in at least the first two years post- myocardial infarction, and has been proven to favorably influence the circadian rhythm of coronary events. Nitrates are the most effective vasodilators with added properties of lowering preload and afterload. Calcium channel blockers are complimentary when ischemic episodes occur at rest or without any precipitating causes. Since silent ischemia is primarily a problem of supply, ie, increased vasomotor tone and vasoconstriction, and occurs more frequently than angina in the clinical spectrum of the total ischemic burden, therapy with calcium channel blockers are very useful. Nifedepine is the ideal calcium channel blocker having the least probability of lowering left ventricular function without negative chronotropic or dromotropic effects. Accordingly, it is readily used in combination with a beta blocker. Finally, if there are no contraindications, 80 to 160 mg of aspirin daily is currently routine treatment and lowers the potential for ischemic events by preventing platelet aggregation.

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