Short Term Effect of Diltiazem on Myocardial Perfusion in Patients With Isolated Coronary Artery Ectasia- a Prospective Clinical Study

Coronary artery ectasia (CAE) has been defined as localized or diffuse dilatation of epicardial coronary arteries more than 1.5 fold of adjacent normal segments. Isolated CAE constitutes minor portion of the total CAE cases, with an incidence of 0.1% to 0.79% in which coronary artery stenosis or severe valvular heart diseases are not present. CAE represents not only an anatomical variant but also a clinical constellation of coronary artery disease (CAD) like association with myocardial ischemia and acute coronary syndromes. Patients with CAE without significant coronary narrowing may still present with angina pectoris, positive stress tests, or acute coronary syndromes. Impaired epicardial and microvascular perfusion were demonstrated in ectatic coronary arteries.

Myocardial blush grading (MBG) technique has been utilized in various conditions such as acute myocardial infarction, coronary artery ectasia, syndrome X and idiopathic dilated cardiomyopathy to evaluate myocardial perfusion.

There is still no consensus for management of CAE. Previously improvement of coronary flow has been demonstrated by mibefradil in patients with slow coronary flow. A new trial is needed to explore the effect of calcium channel blockers (CCB) in isolated CAE. Diltiazem improves myocardial perfusion by blocking calcium channels in coronary arteries. This agent has been widely used in coronary catheter labs to prevent and treat no-reflow.

The current study with prospective design was therefore set up to assess whether epicardial flow and tissue level perfusion would be improved by diltiazem in myocardial regions subtended by the ectatic coronary arteries among patients with isolated CAE.