Usefulness of pharmacologic stress echocardiography for the long-term prognostic assessment of patients with typical versus atypical chest pain

Abstract

T report evaluates the long-term prognostic value of pharmacologic stress echocardiography (PSE) in a large cohort of unselected patients with chest pain of unknown origin and normal left ventricular function at rest. Moreover, we sought to verify the prognostic accuracy of the test in subjects with typical or atypical chest pain. • • • All patients with chest pain of unknown origin who underwent PSE in 3 primary care cardiology centers from April 1994 to December 1999 were considered suitable for the study. Clinical characteristics and indications for testing were recorded prospectively. Inclusion criteria were: (1) history of chest pain; (2) absence of proved coronary artery disease (CAD) defined by history of myocardial infarction, previous hospital admission for unstable angina, previous coronary revascularization, or 70% diameter stenosis of 1 major coronary vessel; (3) normal wall motion at rest by 2-dimensional echocardiography; (4) sinus rhythm; and (5) availability of direct and reliable follow-up information. Exclusion criteria were: (1) significant valvular disease, (2) left bundle branch block, (3) dilated or hypertrophic cardiomyopathy, and (4) technically inadequate echocardiographic examination. Based on the previously mentioned criteria, 904 consecutive patients were enrolled in the study (mean age SD 61 10 years; 380 men and 524 women). The pretest likelihood of CAD was estimated from age, gender, and symptoms,1 and 70% probability was considered as the cut-off value between low to intermediate and high risk. Patients underwent PSE with either dipyridamole (n 594) or dobutamine (n 310). The choice of 1 test over the other was governed by several possible factors, such as clinical issue, personal experience of the operator, and known contraindications to the use of the available drug (severe obstructive pulmonary disease in the case of dipyridamole or a preexisting complex ventricular arrhythmias in the case of dobutamine). PSE was performed after washout from antianginal drugs in 703 patients (77%). The remaining patients were evaluated while receiving blockers (n 104, 11%), nitrates (n 44, 5%), calcium channel blockers (n 31, 3%), or a combined treatment of 2 of the 3 drugs (n 22, 2%). In addition, in patients evaluated by dipyridamole, the administration of any phyllinecontaining drugs or beverages was avoided during the last 12 hours before the test. Two-dimensional echocardiography and 12-lead electrocardiographic monitoring were performed during intravenous administration of either dipyridamole ( 0.84 mg over 10 minutes) or dobutamine ( 40 g/kg/min) combined with atropine ( 1 mg) in case of heart rate 85% of the maximum predicted value.2,3 Criteria for test interruption were the achievement of peak dipyridamole or dobutamine dose, achievement of 85% of the age-predicted maximum heart rate, onset of new wall motion abnormalities, severe chest pain, horizontal or downsloping ST-segment depression 0.2 mV or ST-segment elevation 0.1 mV in 2 contiguous leads, systolic blood pressure 230 mm Hg, diastolic blood pressure 120 mm Hg, decrease in systolic blood pressure 30 mm Hg, significant arrhythmias, and intolerable symptoms. Echocardiographic images were recorded on SVHS videotapes and digitally stored on magneto-optic disk for subsequent analysis. Regional wall motion was assessed with a 16-segment model of the left ventricle and semiquantitatively graded from 1 to 4 (1 normal, 2 hypokinesia, 3 akinesia, 4 dyskinesia). PSE results were considered positive for ischemia in the presence of new regional wall motion abnormalities. Any ST-segment shift 0.1 mV from baseline at 80 ms after the J point in 2 contiguous leads was also recorded for the study. Follow-up data were collected during scheduled periodic visits in our outpatient clinic by a review of the patient’s hospital records and by communication with the patient’s physician. In the absence of reliable information, a telephone interview with the patient was conducted by trained personnel. One year was the minimum accepted period of follow-up in the absence of events. Death and nonfatal myocardial infarction were the events considered for the study. Because of the difficulty of ascribing a cardiac origin to sudden death,4 overall mortality was considered. The diagnosis of acute myocardial infarction was made based on symptoms, electrocardiographic changes, and an increase in cardiac enzyme levels. Only the first event was considered for each patient. The data were anaFrom the Cardiology Division, “S. Spirito” Hospital, Rome; Cardiology Unit, “Campo di Marte” Hospital, Lucca; Cardiology Division, G.B. Grassi Hospital, Rome; and Cardiovascular Research Foundation, Castelfranco Veneto, Italy. Dr. Coletta’s address is: Via Annia 26, 00184 Rome, Italy. E-mail: cole.clau@libero.it. Manuscript received July 29, 2002; revised manuscript received and accepted October 9, 2002.