Unstable angina: role of silent ischemia and total ischemic time (silent plus painful ischemia), a 6-year follow-up

Department of Cardiology II, Policlinico UMBERTO I, Rome, Italy.

To assess the long-term prognostic significance of total ischemic time (silent plus painful ischemia) and silent ischemia in patients with unstable angina whose condition stabilized with medical treatment, 76 patients were studied. All patients underwent Holter ambulatory electrocardiographic (ECG) monitoring for greater than or equal to 48 h beginning within the 1st 12 h of the hospital stay. Forty-three patients (Group A) had a total ischemic time greater than or equal to 60 min, whereas 33 patients (Group B) had a total ischemic time less than 60 min. More than 78% of the ischemic episodes in patients in Group A and 62% of those in Group B were silent (p less than 0.05); nine patients in Group A and six in Group B had only silent episodes. Patients in Group A frequently showed three-vessel disease (65% vs. 18%, p less than 0.01), angiographic findings of subtotal occlusion of the coronary arteries (TIMI grade I) (76.7% vs. 42.4%, p less than 0.01) and ischemic alterations in the rest ECG (51.2% vs. 30.3%, p less than 0.05). During a 6-year follow-up period, 15 patients in Group A and 8 in Group B experienced myocardial infarction (p less than 0.05); 9 patients in Group A and 4 in Group B required coronary artery surgery (p less than 0.05) and 10 patients in Group A and 4 in Group B died of cardiac causes (p less than 0.01). Multivariate analysis showed three-vessel disease to be the most important predictor of cardiac mortality and morbidity (p = 0.025); it was followed in predictive power by a total ischemic time greater than or equal to 60 min and by left ventricular dysfunction. The presence of silent ischemia was not shown to be an independent predictor of long-term morbidity and mortality. In conclusion, patients with unstable angina and a total ischemic time greater than or equal to 60 min frequently have silent ischemic episodes on Holter ECG monitoring, a greater extent of coronary atherosclerosis and ischemic alterations of the rest ECG. The long-term prognosis of patients with unstable angina whose condition stabilizes with medical treatment depends on the extent of coronary atherosclerosis and on the longer duration of total ischemic time but not on the presence of silent ischemia.

This article has been cited by other articles:

				B L Norgaard, K Andersen, K Thygesen, J Ravkilde, P Abrahamsson, L Grip, and M Dellborg Long term risk stratification of patients with acute coronary syndromes: characteristics of troponin T testing and continuous ST segment monitoring Heart, July 1, 2004; 90(7): 739 - 744. [Abstract] [Full Text] [PDF]

				P. F. Cohn, K. M. Fox, and C. Daly Silent Myocardial Ischemia Circulation, September 9, 2003; 108(10): 1263 - 1277. [Full Text] [PDF]

				G. Heper and M. Bayraktaroglu The Importance of von Willebrand Factor Level and Heart Rate Changes in Acute Coronary Syndromes: A Comparison with Chronic Ischemic Conditions Angiology, May 1, 2003; 54(3): 287 - 299. [Abstract] [PDF]

				J. A. Ambrose and G. Dangas Unstable Angina: Current Concepts of Pathogenesis and Treatment Arch Intern Med, January 10, 2000; 160(1): 25 - 37. [Abstract] [Full Text] [PDF]

				P. Abrahamsson, K. Andersen, P. Eriksson, and M. Dellborg Prognostic value of maximum ST-vector magnitude during the first 24h of vectorcardiographic monitoring in patients with unstable angina pectoris Eur. Heart J., August 2, 1999; 20(16): 1166 - 1174. [Abstract] [PDF]

				P. Klootwijk, S. Meij, R. Melkert, T. Lenderink, and M. L. Simoons Reduction of Recurrent Ischemia With Abciximab During Continuous ECG-Ischemia Monitoring in Patients With Unstable Angina Refractory to Standard Treatment (CAPTURE) Circulation, October 6, 1998; 98(14): 1358 - 1364. [Abstract] [Full Text] [PDF]