Severe transmural myocardial ischemia after dipyridamole administration implicating coronary steal

Dipyridamole-induced STEMI: case report and review of the literature

Dipyridamole nuclear myocardial perfusion imaging is a safe and useful modality for assessing myocardial ischemia. It is the modality of choice for cardiac risk stratification in patients who are unable to exercise. Intravenous dipyridamole causes coronary vasodilation and may result in heterogeneity of coronary blood flow in significant coronary artery disease. Ischemic electrocardiographic changes following pharmacological stress testing are less likely to occur compared with exercise stress tests. Ischemia is more likely to be present in the form of ST depression, with ST-segment elevation being exceedingly rare. We present the case of a 73-year-old patient who developed ST-segment elevation myocardial infarction following pharmacologic stress testing.

A case report of dipyridamole stress-induced ST depression progressing to ST-elevation myocardial infarction despite intravenous aminophylline: steal, spasm, or something else?

BACKGROUND

Dipyridamole stress is commonly used for myocardial perfusion imaging and is generally safe. Myocardial ischaemia can occasionally occur and is classically thought to be due to coronary steal as a result of redistribution of flow away from collateral dependent myocardium. Although ischaemia more commonly presents as electrocardiographic (ECG) ST depression and angina, ST-elevation myocardial infarction may occur as a very rare complication.

CASE SUMMARY

We report a case of a patient who developed chest pain and ST depression during dipyridamole infusion. The pain persisted despite intravenous aminophylline with new inferior ST elevation soon after. Coronary angiography showed subtotal right coronary artery occlusion with no collateral supply. The symptoms and ECG changes resolved after percutaneous coronary intervention.

DISCUSSION

Coronary steal may not fully account for our patient's presentation given the failure of aminophylline and absent angiographic collaterals. Vasospasm may be triggered by dipyridamole and can directly cause ischaemia or provoke rupture of an unstable plaque. Augmentation of cardiac energetics during vasodilator stress may also play a role.

Coronary angiographic significance of hyperacute ST-T changes associated with regadenoson stress

An abnormal electrocardiographic stress test is typically characterized by ST segment depression. In rare cases, ST segment elevation is observed, which, in the absence of diagnostic Q waves, has anatomic specificity for localized myocardial ischemia. Most instances of ST elevation occurring during cardiac stress testing have been observed with exercise, with only six cases reported with pharmacologic stress. Despite different physiologic mechanisms for inducing myocardial ischemia, development of ST segment elevation during pharmacologic stress, as illustrated by the present case, may also be indicative of critical coronary stenoses, warranting urgent coronary arteriography.

Secondary prevention of stroke: a practical guide to drug treatment

Stroke is a disease of the elderly and, as a result of the expected demographic changes in many industrialised countries, its incidence is likely to increase in the future. A first-ever stroke significantly increases the likelihood of further events; thus, secondary prevention is of major importance. Only a minority of recurrent strokes can be prevented by surgical or other invasive methods, meaning that most secondary preventive measures involve drug treatment, which has become increasingly sophisticated in recent years. Ischaemic stroke constitutes the vast majority of all strokes; effective secondary prevention depends on a variety of factors, of which the correct classification in terms of subtypes and aetiological mechanisms is a pivotal prerequisite, as is the assessment of the patient's cardiovascular risk profile. In addition to the evaluation of pathomechanisms, stratification of subtypes of brain infarction is mainly based on morphology seen with brain imaging techniques, which provides additional evidence for the presumed cause of the stroke. Inhibitors of platelet function and anticoagulants are the two major groups of antithrombotic drugs used for the secondary prevention of stroke. Antiplatelet agents are still indicated in the majority of patients after ischaemic stroke, especially if an arterial origin is presumed. In addition to aspirin (acetylsalicylic acid), the position of which as the first-line antiplatelet drug is increasingly being questioned, other compounds with antiplatelet activity have been developed and have proven effective in secondary stroke prevention, including ticlopidine, clopidogrel and dipyridamole. Anticoagulants are principally indicated after cardioembolic ischaemic stroke; however, their inherent bleeding risks render their use in many cases rather difficult, in particular for elderly patients. Patient compliance with the recommended treatment is of major importance, given the somewhat limited efficacy of antithrombotic agents in stroke prevention. Since 'real world' experience does not match the circumstances under which clinical trials are conducted, this article will also deal with problems not covered by specific studies, such as risk stratification for anticoagulant treatment and how to proceed in cases of unknown stroke aetiology. The management of major cardiovascular risk factors is the other mainstay of secondary stroke prevention. Recent evidence indicates that antihypertensive treatment may be as effective as antithrombotic drugs for secondary prevention of stroke. This still needs to be proven for the treatment of other cardiovascular risk factors, such as diabetes mellitus and hypercholesterolemia. Nevertheless, the results of recent studies investigating the effect of HMG-CoA reductase inhibitors ('statins') on cardiovascular events strongly suggest a stroke-preventive effect.

Dipyridamole-induced ST-segment elevation indicative of transmural myocardial ischemia--a case report

Dipyridamole nuclear myocardial perfusion test is a safe and effective alternative to exercise nuclear perfusion testing for detecting myocardial ischemia. It is the procedure of choice in selected patients who are unable to exercise adequately. Intravenous dipyridamole causes coronary vasodilation with resultant maldistribution and heterogeneity of coronary flow in the presence of significant coronary artery disease. True ischemia, causing symptoms or ST-segment depression, is uncommon, in part because there is no increase in myocardial oxygen demand. A patient in whom myocardial ischemia developed, manifested by ST-segment elevation, during dipyridamole stress testing is described. Scintigraphic images illustrated a myocardial perfusion defect, which was consistent with coronary angiographic findings. This case report addresses the importance of dipyridamole-induced ST-segment elevation, its correlation with angiographic findings, and the need for continued hemodynamic and electrocardiographic monitoring in patients following dipyridamole infusion.