Long-term prognosis in women with normal dobutamine stress echocardiography

I patients with known or suspected coronary artery disease, dobutamine stress echocardiography (DSE) has proved accurate in assessing myocardial viability and predicting cardiac risk after myocardial infarction or before major noncardiac surgery.1–5 Long-term follow-up of patients with normal cardiac angiograms has shown that these patients have an excellent prognosis.6–8 Likewise, 1to 10-year follow-up of patients with normal myocardial perfusion studies, as assessed by exercise thallium testing, has revealed these patients have an excellent cardiac prognosis, with a #1% likelihood of cardiac death or myocardial infarction.9–11 Although the long-term prognosis for patients with a normal dobutamine stress echocardiographic result is good,12,13 most studies of such patients have focused on men. Fewer data exist regarding the long-term prognosis for women. In this study, we assess the long-term cardiac prognosis for women with a normal dobutamine stress echocardiogram. • • • We reviewed the cases of 120 women who underwent DSE for evaluation of chest pain between January 1993 and February 1997. All of the women achieved $85% of the maximum predicted heart rate and had a normal test result. Twenty of the patients were from abroad and were excluded from the study because they were unavailable for telephone followup. In the remaining 100 cases, all of the referring physicians provided written consent for including their patients in the study, which was approved by our hospital’s institutional review board. Each patient’s age, cardiac risk factors (Table I), and clinical history were obtained from previous medical records. Follow-up information was obtained by direct telephone contact. Patients who had chest discomfort were considered to have typical angina if the discomfort was substernal, precipitated by physical exertion, and relieved by rest or nitroglycerin. They were considered to have atypical angina if the discomfort was not substernal, not precipitated by exertion, or not relieved by rest or nitroglycerin. If $2 of the latter 3 characteristics were absent, the discomfort was considered nonanginal. DSE was performed with an integrated HewlettPackard Sonos 1500 or 2500 ultrasonograph (HewlettPackard, Andover, Massachusetts) and a Freeland Prism/Imaging System (Broomfield, Colorado). A progressively graded dobutamine infusion was given, using the following protocol, in which each stage lasted approximately 3 minutes: 5, 10, 20, 30, 40, and 50 mg/kg/min. If necessary, atropine was added (maximum dose 1 mg). As described elsewhere,1 digitized images were acquired at baseline and during DSE at a low dose (10 mg/kg/min), at the peak dose, and at recovery. All studies were supervised and interpreted by an experienced echocardiographer. A normal result was characterized by augmented left ventricular systolic function and the absence of a new regional wall motion abnormality at peak stress. Data were reviewed to verify the initial findings in the cases of all patients who had a cardiac event. Follow-up data were obtained by direct telephone contact and a review of hospital records up to September 1997. Risk factors were determined as previously mentioned. Adverse events were categorized as cardiac death, congestive heart failure, myocardial infarction, or need for revascularization (angioplasty or coronary artery bypass grafting). Adverse cardiac events were analyzed by a Kaplan-Meier survival curve. From St. Luke’s Episcopal Hospital/Texas Heart Institute and Baylor College of Medicine, Houston, Texas. Dr. Wilansky’s address is: 6624 Fannin, Suite 2480, Houston, Texas 77030. E-mail: hallgar@hgcardio.com. Manuscript received September 24, 1998; revised manuscript received and accepted November 30, 1998. TABLE II Adverse Events After Normal Dobutamine Stress Echocardiography