Percutaneous Transluminal Coronary Angioplasty for Silent Myocardial lschemia Henry S. Cabin, MD
I
n the 13yearssincethe first percutaneoustransluminal coronary angioplasty (PICA) was performed,’ the number of procedures performed has increased dramatically. This in part relates to a greater availability of the procedure to patients with coronary artery disease as the number of operators has increased, but it also reflects an expansionof the indications for PTCA.* The indications for any therapeutic intervention should be basedon its potential benefits, the likelihood of success,the frequency of complications and the subsequent morbidity and mortality. A comparison of earlier and more recent series of patients undergoing PTCA has documented an increase in success rate and a decreasein complication rate.3 The only proven benefit of PTCA, however, remains the relief of symptomatic myocardial ischemia. Whether PTCA also favorably alters the risk of subsequent myocardial infarction or death in patients with symptomatic ischemia can only be inferred from a comparisonof studies of outcomesin patients undergoing PTCA with other studies of patients who have been treated with medical therapy. There have been no randomized studies comparing outcomes in patients with angina treated medically versus those undergoing PTCA. Becauseof its efficacy in relieving angina, however, PTCA has become a widely acceptedalternative to surgical and medical therapy in symptomatic patients with I- or multivessel coronary artery disease. The role of PTCA in asymptomatic patients remains poorly defined. Becausethis group of patients will not have any immediate symptomatic benefit from PTCA, the indication for PTCA must be basedon its impact on subsequent morbidity and mortality. Several studies have demonstrated that patients with coronary artery diseasehave an increased risk of myocardial infarction or death if they have evidenceof inducible or spontaneous myocardial ischemia whether or not ischemia is associatedwith pain.4~5The extent and location of the coronary narrowing, the presenceand severity of left ventricular dysfunction, the level of exercise achieved on the treadmill and the extent of ischemia at peak exercise are generally accepted as predictors of outcome whether or not the patient is symptomatic.6Thus, patients with silent myocardial ischemia, excellent exercise From the Section of Cardiology, Yale University School of Medicine, New Haven, Connecticut. Mantipt received and accepted Septemher 21, 1989. Address for reprints: Henry S. Cabin, MD, Yale University School of Medicine, Section of Cardiology, 333 Cedar Street, PO Box 3333, New Haven, Connecticut 065 10.
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capacity, l-vessel coronary artery diseaseand normal left ventricular function have an excellent long-term prognosiswhile similarly asymptomatic patients with 3vesselcoronary disease,depressedleft ventricular function and poor exercise capacity will have a relatively high risk of subsequentmyocardial infarction or death. Although it is clear that a subgroup of patients with asymptomatic myocardial ischemia will benefit from surgical revascularization (i.e., those with 3-vesselcoronary diseaseand left ventricular dysfunction and those with left main coronary stenosis)it is unclear which, if any, asymptomatic patients will benefit from PTCA. In the present issue of the Journal, Anderson et al7 report the long-term outcome of 114 patients who underwent PTCA and never had angina pectoris or myocardial infarction. These 114 patients represent
I
n the 13yearssincethe first percutaneoustransluminal coronary angioplasty (PICA) was performed,’ the number of procedures performed has increased dramatically. This in part relates to a greater availability of the procedure to patients with coronary artery disease as the number of operators has increased, but it also reflects an expansionof the indications for PTCA.* The indications for any therapeutic intervention should be basedon its potential benefits, the likelihood of success,the frequency of complications and the subsequent morbidity and mortality. A comparison of earlier and more recent series of patients undergoing PTCA has documented an increase in success rate and a decreasein complication rate.3 The only proven benefit of PTCA, however, remains the relief of symptomatic myocardial ischemia. Whether PTCA also favorably alters the risk of subsequent myocardial infarction or death in patients with symptomatic ischemia can only be inferred from a comparisonof studies of outcomesin patients undergoing PTCA with other studies of patients who have been treated with medical therapy. There have been no randomized studies comparing outcomes in patients with angina treated medically versus those undergoing PTCA. Becauseof its efficacy in relieving angina, however, PTCA has become a widely acceptedalternative to surgical and medical therapy in symptomatic patients with I- or multivessel coronary artery disease. The role of PTCA in asymptomatic patients remains poorly defined. Becausethis group of patients will not have any immediate symptomatic benefit from PTCA, the indication for PTCA must be basedon its impact on subsequent morbidity and mortality. Several studies have demonstrated that patients with coronary artery diseasehave an increased risk of myocardial infarction or death if they have evidenceof inducible or spontaneous myocardial ischemia whether or not ischemia is associatedwith pain.4~5The extent and location of the coronary narrowing, the presenceand severity of left ventricular dysfunction, the level of exercise achieved on the treadmill and the extent of ischemia at peak exercise are generally accepted as predictors of outcome whether or not the patient is symptomatic.6Thus, patients with silent myocardial ischemia, excellent exercise From the Section of Cardiology, Yale University School of Medicine, New Haven, Connecticut. Mantipt received and accepted Septemher 21, 1989. Address for reprints: Henry S. Cabin, MD, Yale University School of Medicine, Section of Cardiology, 333 Cedar Street, PO Box 3333, New Haven, Connecticut 065 10.
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THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 65
capacity, l-vessel coronary artery diseaseand normal left ventricular function have an excellent long-term prognosiswhile similarly asymptomatic patients with 3vesselcoronary disease,depressedleft ventricular function and poor exercise capacity will have a relatively high risk of subsequentmyocardial infarction or death. Although it is clear that a subgroup of patients with asymptomatic myocardial ischemia will benefit from surgical revascularization (i.e., those with 3-vesselcoronary diseaseand left ventricular dysfunction and those with left main coronary stenosis)it is unclear which, if any, asymptomatic patients will benefit from PTCA. In the present issue of the Journal, Anderson et al7 report the long-term outcome of 114 patients who underwent PTCA and never had angina pectoris or myocardial infarction. These 114 patients represent
