CURRICULUM IN CARDIOLOGY PTCA of chronically occluded coronary arteries

The progression of a coronary artery stenosis to total occlusion does not necessarily imply complete myocardial necrosis of the entire flow-dependent region of the vessel involvedJ Various degrees of perfusion can be maintained by a collateral circulation, so that the area of necrosis can be limited in size or infarction can even be prevented. During increased demand for myocardial oxygen the collateral blood flow may become insufficient, and symptoms of myocardial ischemia may arise. Signs of viable myocardial tissue are: angina pectoris in the absence of other significant coronary artery lesions, absence of Q waves on the electrocardiogram, the preservation of left ventricular wall motion as shown by angiographic or echocardiographic techniques, and redistribution on thallium 201 scintigraphy. 2,3 Angina pectoris (even unstable angina pectoris) may persist in spite of an optimal antiischemic drug regimen. Percutaneous recanalization, followed by balloon dilatation, appears to be an attractive approach, since coronary bypass graft surgery, although a safe procedure, is now generally not considered to be the best treatment for single-vessel coronary artery disease. Percutaneous transluminal coronary angioplasty (PTCA) of chronically occluded coronary arteries, first described in 1982, 4, 5 comprises approximately 10% of the total number of PTCA procedures.2, 6-9 This article reviews the factors that determine the initial success of angioplasty of chronic total coronary artery occlusions, as well as the clinical and angiographic follow-ups. A decision scheme for the approach to treatment of the patient with a chronic total occlusion is presented, and guidelines for the PTCA procedure are proposed. New tech-