Prognostic value of early exercise stress testing after successful coronary angioplasty: importance of the degree of revascularization

Prediction of Post Percutaneous Coronary Intervention Myocardial Ischaemia

Following revascularisation the majority of patients obtain symptom relief and improved quality of life. However, myocardial ischaemia may recur or persist in a significant patient subset. Symptom recurrence is usually attributed to inaccurate evaluation of epicardial stenosis, incomplete revascularisation or stent failure and disease progression. However, technological advances with modern imaging and/or physiological evaluation of epicardial plaques have not solved this issue. Conversely, recent clinical studies have shown that abnormal coronary vasomotion and increased myocardial resistance are frequent determinants of post-percutaneous coronary intervention (PCI) myocardial ischaemia. Strategies to enhance prediction of post-PCI angina include proper selection of patients undergoing revascularisation, construction of clinical prediction models, and further invasive evaluation at the time of coronary angiography in those with high likelihood.

Stress Testing After Complete and Successful Coronary Revascularization

BACKGROUND

Noninvasive stress tests play a determinant role in the initial management of patients with chronic angina. Nonetheless, their use in the same patient population is considered inappropriate within 2 years after percutaneous coronary intervention (PCI). Indeed, early abnormal results correlate less well with angiographic control and are attributed to a number of confounding factors. We prospectively assessed prevalence and impact on the quality of life of abnormal stress test results in a highly selected patient population.

METHODS

Patients with no cardiac comorbidities who underwent successful and complete PCI with stenting for typical angina and had an abnormal exercise stress test (EST) under guideline-directed medical treatment were administered the Seattle Angina Questionnaire (SAQ). Clinical evaluation, EST, and the SAQ were repeated at 1, 6, and 12 months after the index PCI.

RESULTS

One hundred ninety-eight patients qualified and were included in the study (mean age, 64 years; 79% men). Although the majority had normal EST results or an increased threshold to angina, at 1 month after the index PCI, 29% of patients still had an abnormal result. At 6 and 12 months, 31% and 29% of patients had abnormal results, respectively. Quality-of-life assessment by the SAQ showed consistent results, with persistent angina in one third of patients. Control angiography documented a critical lesion, attributable to in-stent coronary restenosis, in only 8% of patients.

CONCLUSIONS

When stress testing is systematically performed after PCI, the prevalence of abnormal results is high and is associated with impaired quality of life. Prognostic significance along with the underlying pathophysiological mechanisms of such findings should be investigated.

Obstructive coronary atherosclerosis and ischemic heart disease: an elusive link!

In the current pathophysiological model of chronic ischemic heart disease (IHD), myocardial ischemia and exertional angina are caused by obstructive atherosclerotic plaque, and the clinical management of IHD is centered on the identification and removal of the stenosis. Although this approach has been in place for years, several lines of evidence, including poor prognostic impact, suggest that this direct relationship may present an oversimplified view of IHD. Indeed, a large number of studies have found that IHD can occur in the presence or absence of obstructive coronary artery disease and that atherosclerosis is just 1 element in a complex multifactorial pathophysiological process that includes inflammation, microvascular coronary dysfunction, endothelial dysfunction, thrombosis, and angiogenesis. Furthermore, the high recurrence rates underscore the fact that removing stenosis in patients with stable IHD does not address the underlying pathological mechanisms that lead to the progression of nonculprit lesions. The model proposed herein shifts the focus away from obstructive epicardial coronary atherosclerosis and centers it on the microvasculature and myocardial cell where the ischemia is taking place. If the myocardial cell is placed at the center of the model, all the potential pathological inputs can be considered, and strategies that protect the cardiomyocytes from ischemic damage, regardless of the causative mechanism, can be developed.

Pre-discharge exercise test for evaluation of patients with complete or incomplete revascularization following primary percutaneous coronary intervention: a DANAMI-2 sub-study

OBJECTIVES

It is unclear whether the completeness of revascularization impacts on the prognostic value of an exercise test after primary percutaneous coronary intervention (PCI).

METHODS

The DANAMI-2 trial included patients with ST elevation acute myocardial infarction randomized to primary PCI or fibrinolysis. Of the 790 patients randomized to primary PCI, 572 performed an exercise test. Prospectively, 310 patients were classified as having complete and 216 as having incomplete revascularization. Primary endpoint was a composite of reinfarction and/or death.

RESULTS

Patients with incomplete revascularization had lower exercise capacity [6.5 (95% CI: 1.9-12.8) vs. 7.0 (95% CI: 2.1-14.0) METs, p = 0.004] and more frequently ST depression [43 (20%) vs. 39 (13%), p = 0.02] compared to patients with complete revascularization. ST depression was not predictive of outcome in either groups, while multivariable analyses showed that exercise capacity was predictive of reinfarction and/or death in patients with incomplete revascularization [hazard ratio = 0.71 (95% CI: 0.54-0.93), p = 0.012] or of death alone [hazard ratio = 0.56 (95% CI: 0.41-0.77), p = 0.0003], which was not found in patients with complete revascularization.

CONCLUSIONS

Exercise capacity was prognostic of reinfarction and/or death in patients with incomplete revascularization, but not in completely revascularized patients. ST segment depression alone did not predict residual coronary stenosis or dismal prognosis.

The predictive value of exercise QRS duration changes for post-PTCA coronary events

BACKGROUND

The sensitivity and predictive values of exercise ECG testing using ST-T criteria after percutaneous transluminal coronary angioplasty (PTCA) are low, precluding its routine use for screening for restenosis. The predictive value of QRS duration criteria during exercise testing (ET) ECG after PTCA for future coronary events has not been reported. The aim of the study was to compare QRS duration changes with ST-T criteria during ET, as a predictor of coronary events after PTCA.

METHODS

A prospective study of 206 consecutive patients who underwent ET at a mean of 34 +/- 14 days after their first PTCA, and were the followed for a mean of 23 +/- 9 months. Patients were divided by QRS duration into two groups-Q1: ischemic response (QRS duration prolongation of more than 3 ms relative to the resting duration), and Q2: normal response (QRS duration shortening or without change from resting duration). Patients were also divided by their ST-T response, S1: ischemic response, and S2: normal response.

RESULTS

During follow-up 52 patients (58%) experienced restenosis or MI, or underwent CABG-Q1: 44 (85%), Q2: 8(15%) (P < 0.0002), S1: 8 (15%), S2: 44 (85%), (P < 0.641), two patients died-Q1: 1 (1%) and Q2: 1 (1%). For QRS and ST-T, the relative risk of having at least one of the coronary events was 4.02 (CI 2.1-9.9) versus 1.13 (CI 0.8-2.9), respectively. The sensitivity for future coronary events was 85% and 52% and the specificity was 48% and 98% for the QRS and ST-T criteria, respectively.

CONCLUSION

QRS prolongation during peak ET ECG after PTCA is a more sensitive marker than ST-T criteria for detection of patients at risk for later coronary events.

Use of stress testing to evaluate patients with recurrent chest pain after percutaneous coronary revascularization

Controversy exists regarding the diagnostic accuracy, optimal technique, and timing of noninvasive stress testing after percutaneous transluminal coronary angioplasty (PTCA). Many patients return with chest pain after PTCA, and because the incidence of restenosis has been reported to be as high as 50%, a noninvasive test with a high predictive value is needed to reduce the need for unnecessary coronary angiography. Studies have shown that the sensitivity and specificity of stress testing varies depending on the amount of time elapsed since the procedure. Soon after a successful PTCA, perfusion defects on nuclear imaging following exercise or pharmacologic stress may be detected in asymptomatic patients without angiographic restenosis. In many patients, abnormal stress myocardial perfusion scans will normalize spontaneously, and thus stress testing with nuclear imaging within 4 to 6 weeks of PTCA lacks specificity for detecting restenosis. In contrast, stress echocardiography which detects wall motion abnormalities rather than perfusion mismatch has been reported to offer more specific information on myocardial ischemia and restenosis early after PTCA. In patients who develop chest pain more than 6 weeks after PTCA, the ability to accurately identify restenosis is shared by both echocardiographic and nuclear imaging methods. The purpose of this review is to clarify the strengths, pitfalls, and prognostic value of different stress modalities and cardiac imaging techniques in patients who develop chest pain within 6 months of undergoing PTCA.

Clinical and prognostic usefulness of supine bicycle exercise echocardiography in the functional evaluation of patients undergoing elective percutaneous transluminal coronary angioplasty

BACKGROUND

Supine bicycle exercise echocardiography (SBEE) has never been used before and early after percutaneous transluminal coronary angioplasty (PTCA) for assessing the functional outcome of the procedure and predicting late restenosis.

METHODS AND RESULTS

We selected 76 subjects with stable angina, normal wall motion at rest, and exercise-induced wall-motion abnormalities before PTCA. SBEE with peak exercise imaging and the use of a 16-segment, four-grade score model was performed 54 +/- 15 hours after PTCA. No exercise-related adverse events occurred. Patients were grouped according to SBEE results: group 1 (n = 35, 46%) with negative exercise ECG and echo; group 2 (n = 19, 25%) with a positive exercise ECG but normal echo; and group 3 (n = 22, 29%) with a positive exercise echo with either a positive (n = 7, 32%) or negative (n = 15, 68%) ECG. Exercise performance significantly improved in all groups. In group 3, peak wall-motion score index decreased from 1.27 +/- 0.11 before to 1.15 +/- 0.06 after PTCA (P < .05), and duration of wall-motion abnormalities went from 81 +/- 24 to 47 +/- 19 seconds (P < .05). The rate of clinical restenosis (ie, angina recurrence or positive 6-month SBEE in asymptomatic patients, both associated with angiographic restenosis > 50%) was 37%. By multiple logistic regression analysis, clinical restenosis was associated with a positive post-PTCA exercise echo (odds ratio [OR] 3.08, 95% confidence interval [CI] 1.66 to 5.72; P = .0004) and with increasing values of pre-PTCA wall-motion score index (OR 2.86, 95% CI 1.92 to 4.27; P = .005) and duration of wall-motion abnormalities (OR 2.12, 95% CI 1.07 to 4.20; P = .04).

CONCLUSIONS

SBEE is a safe and reliable tool to demonstrate changes in exercise-induced wall-motion abnormalities after PTCA and provides prognostic information in the risk assessment of clinical restenosis.

The importance of completeness of revascularization during long-term follow-up after coronary artery operations

Completeness of revascularization after coronary artery bypass operation has been shown to improve short- and medium-term outcome. The purpose of this study was to assess the independent contribution of completeness of revascularization to long-term outcome. A total of 2057 patients with multivessel disease with complete revascularization and 803 with incomplete revascularization, mean age 57 +/- 9 years, was studied. The patient groups were similar except for more prior myocardial infarctions, worse left ventricular function, and more three-vessel disease in the incomplete revascularization group. Complications of perioperative infarction and stroke were not different between those having complete versus incomplete revascularization. The hospital death rate for patients having complete revascularization during the period of study was 0.7% versus 1.5% for those having incomplete revascularization (p = 0.06). Length of hospital stay for the two groups of patients also was not different. At late follow-up (mean 11.7 years for complete and 10.8 years for incomplete) patients who had incomplete revascularization had a significantly higher prevalence of recurrent angina. Multivariate analysis demonstrated the strongest predictors of incomplete revascularization to be number of vessels diseased and left ventricular function (ejection fraction). The multivariate correlates of survival were older age, left ventricular dysfunction, and completeness of revascularization. Completeness of revascularization correlated with improved overall patient survival, as well as survival in patients with normal left ventricular function. Furthermore, the curves continued to separate over time, such that the difference was greater at 8 years than at 4 years, although by 12 years the curves started to converge.

Percutaneous transluminal coronary angioplasty as a first revascularization procedure in single-, double- and triple-vessel coronary artery disease

OBJECTIVES

We sought to compare in-hospital and long-term outcome after angioplasty in patients with single-, double- and triple-vessel disease.

BACKGROUND

Coronary angioplasty is increasingly used in patients with multivessel disease.

METHODS

The source of data was the clinical data base at Emory University. Patients who had previous coronary revascularization or who underwent angioplasty in the setting of acute myocardial infarction were excluded.

RESULTS

Of 10,783 patients, 71% had one-vessel, 24% two-vessel and 5% three-vessel disease. Age, male gender, diabetes, hypertension, history of previous myocardial infarction, Canadian Cardiovascular Society class III or IV angina and congestive failure all increased with severity of disease. Complete revascularization was achieved in most patients with one-vessel disease, in a minority with two-vessel disease and rarely in those with three-vessel disease. Emergency coronary bypass surgery increased from 1.7% with one-vessel disease to 3.2% with three-vessel disease. Q wave myocardial infarctions could not be shown to vary significantly with severity of disease. The mortality rate increased from 0.2% with one-vessel disease to 1.2% with three-vessel disease. The number of vessels diseased was a multivariate correlate of in-hospital and long-term mortality. The 1-, 5- and 10-year survival was 0.99, 0.93 and 0.86 for one-vessel disease and 0.97, 0.89 and 0.76 for two-vessel disease, respectively. The 1-, 5- and 9-year survival was 0.95, 0.85 and 0.70 in three-vessel disease, respectively. Freedom from myocardial infarction, coronary bypass surgery and repeat angioplasty was also lower with more severe disease.

CONCLUSIONS

Patients have increasing in-hospital and long-term mortality as the severity of disease increases. There is also an increased incidence of myocardial infarction and revascularization procedures with more severe disease.

The value of exercise electrocardiography testing in the identification of coronary restenosis: a probability analysis

We studied by means of probability analysis the role of exercise ECG in identifying coronary restenosis. A total of 213 patients were independently evaluated by clinical history, conventional assessment of the exercise ECG ('yes or no' statement), D score (a discriminant function derived from exercise ECG), and coronariography, 5.4 +/- 2.8 months after successful coronary angioplasty. The initial probability of restenosis (30%), that is, the prevalence of the condition, was radically changed by the result of clinical history (77% for patients with angina vs. 17% for those without angina). By contrast, ECG binary assessment, due to its low accuracy (70% vs 82% of clinical history, P < 0.005), was unable to significantly change the established probabilities after symptomatic evaluation. Finally, D score, which greatly enhanced specificity (92% vs. 76% of bivariate assessment, P < 0.0001), proved to be useful in changing the probability (from 32% to 76% or to 25%) of patients (n = 34) with a discordant result (no angina/positive exercise ECG). When this stepwise approach was tested in 46 new patients, predicted and observed probabilities were actually very similar. We conclude that exercise ECG has a very limited role in identifying coronary restenosis if positive responses are not adjusted with a weighted score which takes into account other exercise derived factors.

Value and limitations of exercise stress testing to predict the functional results of coronary artery bypass grafting

To assess the value of exercise stress testing to predict the functional result of revascularization, 90 patients were evaluated by coronary angiography and exercise testing pre and postoperatively. Patients were classified on the basis of the postoperative angiogram in a group with successful surgery and a group with unsuccessful surgery. The predictive accuracy positive of ST segment depression to detect unsuccessful surgery was 67% The predictive accuracy negative was 61%. The best predictor of unsuccessful surgery was residual angina pectoris after revascularization with predictive value positive and negative of 85% and 60%, respectively. Thus exercise stress testing has limited value to accurately predict the degree of revascularization.

Clinical assessment following coronary revascularization

There remains a need to establish adequate protocols for investigating the short- and long-term follow-up of revascularization procedures. For coronary angioplasty the most reliable basis for decision-making in managing patients is the symptomatology of the patient. For bypass surgery a protocol should be established to evaluate patients late, at 5 to 10 years following bypass surgery, in particular those with saphenous vein grafting, as graft and patient survival begins to fall after this period. Investigation after this may be too late for many patients who may already have several occluded grafts and poor left ventricular function, two of the most important prognostic factors post bypass surgery. The improvement and refinement of non-invasive investigations has led to a better understanding of the value and limitations of many of these tests, but it is particularly important that the limitations of many investigation are fully appreciated when they are used to influence clinical decisions. In this regard, a study comparing and integrating the predictive value of the persistence or return to symptoms, a positive non-invasive test, and a positive invasive test would surely prove invaluable.

Detection of restenosis with dobutamine stress test after coronary angioplasty

Dobutamine ECG tests were serially performed before, at 15 days, and at 2 and 6 months after successful coronary angioplasty in 58 patients. The dose of dobutamine was progressively increased from 5 micrograms/kg/min to a maximum of 40 micrograms/kg/min every 5 minutes, with ECG and blood pressure control. Coronary angiography was performed at the end of the study. At 15 days after coronary angioplasty, the dobutamine test was of little value for the diagnosis or prediction of restenosis. At the end of the study, both the presence of angina and the results of the dobutamine test were related to coronary angiography, and their accuracy was calculated for the detection of mild (> or = 50%) and severe (> or = 70%) restenosis or new coronary lesions. The accuracy of angina was 68% for the detection of mild lesions and 70% for that of severe lesions, whereas the accuracy of the dobutamine test was 78% for mild lesions and 80% for severe lesions. It is concluded that the dobutamine stress test is a simple and useful method for the detection of restenosis when it is performed at 2 and 6 months after coronary angioplasty. However, it cannot distinguish between restenosis or new coronary lesions.

Midterm outcome of patients with asymptomatic restenosis after coronary balloon angioplasty

Although many patients with restenosis after balloon coronary angioplasty have recurrence of angina, others remain asymptomatic. To assess the clinical implications of asymptomatic coronary restenosis, we analyzed clinical and angiographic characteristics of 277 consecutive patients with restenosis, 133 (48%) of whom were asymptomatic (group I) and 144 (52%) symptomatic (group II). Restenosis was documented 6 to 9 months after the index procedure, or earlier if angina recurred, and was defined as a greater than 50% lumen narrowing (visual estimation). Group I (asymptomatic group) included fewer female (9% vs. 18%, p less than 0.05) and hypertensive patients (38% vs. 56%, p less than 0.005) and more patients with a previous myocardial infarction (48% vs. 28%, p less than 0.05) and single-vessel disease (67% vs. 55%, p less than 0.05). Before angioplasty, symptoms had lasted for a shorter period (10 +/- 25 vs. 23 +/- 42 months, p less than 0.001), ischemia after a recent infarction was a more frequent indication (21% vs. 10%, p less than 0.05) and total revascularization more frequently obtained (74% vs. 63%, p less than 0.05) in group I than in group II patients. Only a normal blood pressure, previous myocardial infarction, single-vessel disease and a shorter duration of symptoms were independent correlates of asymptomatic restenosis. No differences were found in stenosis severity before angioplasty (90% in both groups) or after angioplasty (22% +/- 12% vs. 24% +/- 16%).(ABSTRACT TRUNCATED AT 250 WORDS)

Safety and clinical use of exercise testing one to three days after percutaneous transluminal coronary angioplasty

To evaluate both the safety and clinical use of predischarge symptom-limited exercise testing after successful uncomplicated percutaneous transluminal coronary angioplasty (PTCA), 100 patients were randomized to undergo exercise testing (n = 50) or no exercise testing (n = 50). There were no differences in clinical or angiographic characteristics between the groups. Exercise testing was performed 38 +/- 14 hours after PTCA. Patients who exercised achieved 71 +/- 12% of predicted maximal heart rate, with 38% reaching greater than or equal to stage III of the Bruce protocol. No patient in either group developed cardiac complications during 48-hour follow-up. Of the 11 patients with a positive test result, 92% had angiographically incomplete revascularization. Attending physicians (n = 16) were questioned both before and after exercise testing about when, after discharge, they would allow their patient to perform each of 11 specific activities of daily living. Questionnaires were administered to physicians at similar time frames for patients in the no-exercise group. Comparison of the responses between initial and repeat questionnaires showed that patients in the exercise group (with a test result negative for ischemia) were allowed to perform 7 of 11 activities, including return to work, earlier (p less than 0.05) than the no-exercise patients. These data indicate that in this well-defined group of patients, symptom-limited exercise testing early after PTCA appears to be safe, and alters physician management in allowing patients with a negative test result to return to various activities at an earlier date. Such testing may be useful in counseling patients after PTCA.

PTCA in patients with stable angina pectoris and multivessel disease: is incomplete revascularization acceptable?

Of all coronary angioplasties performed nowadays, 40% of the patients have multivessel disease. Angioplasty in patients with multivessel disease can be performed with a high immediate clinical success rate and an acceptable major complication rate. However, complete anatomic revascularization with coronary angioplasty is achieved in only 32 to 59%. This raises concern about the immediate and long-term outcome of patients in whom incomplete revascularization is achieved. This report reviews the literature and provides evidence that incomplete revascularization with coronary angioplasty is a safe and effective treatment in selected patients with multivessel disease, provided that adequate (functional) revascularization can be achieved. Adequate revascularization includes dilation of all significant lesions supplying large areas of viable myocardium.

Coronary restenosis: what have we learned from angiography?

Coronary restenosis remains a major problem for interventional cardiology not only by virtue of its frequency, but also because of the current inability to prevent it. Symptomatic status and non-invasive evaluation have been used to study restenosis, but both lack specificity and sensitivity, particularly in patients with multivessel disease. Angiography remains the reference standard. Several arbitrary definitions have been used, some related to visual estimates of coronary stenosis and others to quantitative angiographic techniques. In another approach, linear modeling is used to assess minimal luminal diameter of lesions on restudy. Although angiographic studies have been essential in the study of restenosis, questions concerning the underlying mechanism and pathophysiology remain. The development of animal models that closely resemble human restenosis should allow evaluation of pathophysiologic mechanisms and development of new strategies to prevent the problem.

Assessment of "silent" restenosis and long-term follow-up after successful angioplasty in single vessel coronary artery disease: the value of quantitative exercise electrocardiography and quantitative coronary angiography

Exercise electrocardiographic (ECG) testing during follow-up after coronary angioplasty is widely applied to evaluate the efficacy of angioplasty, even in asymptomatic patients. One hundred forty-one asymptomatic patients without previous myocardial infarction underwent quantitative exercise ECG testing and quantitative coronary angiography 1 to 6 months after successful angioplasty in single vessel coronary artery disease to 1) determine the value of exercise ECG testing to detect "silent" restenosis, and 2) assess the long-term prognostic value of exercise ECG testing and coronary angiography. The prevalence of restenosis (defined as greater than or equal to 50% luminal narrowing at the dilation site) was 12% in this selected study group. Of 26 patients with an abnormal exercise ECG (ST segment depression greater than or equal to 0.1 mV), only 4 (15%) showed recurrence of stenosis. Sensitivity and specificity for detection of restenosis were 24% and 82%, respectively. One hundred thirty-four patients (95%) were followed up 1 to 64 months (mean 35) after exercise ECG testing and coronary angiography. Thirty-two patients (24%) experienced a cardiac event: in 25 patients (78%) the initial event was recurrent angina pectoris (New York Heart Association class III or IV) and in 7 patients (22%) it was myocardial infarction, although cardiac death did not occur. The mean interval between exercise ECG testing and the initial cardiac events was 14 months (range 1 to 55), whereas 47% of the initial events took place less than or equal to 6 months after exercise ECG testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful multiple segment coronary angioplasty: effect of completeness of revascularization in single-vessel multilesions and multivessels

A long-term follow-up study was performed to evaluate the long-term value of performing multiple dilatations according to their procedural (single-vessel multilesion or mutltivessel dilatations) and anatomic types (single-vessel disease with multiple dilatations or multivessel disease dilatations with complete and incomplete revascularization). From 1980 until 1988, 248 patients met the following criteria: (1) at least two lesions dilated (range: 2 to 4) and (2) all attempted lesions successfully dilated. The mean length of follow-up was 33 months. The end points analyzed were death, myocardial infarction, redilatation, and bypass surgery. No differences were found for these events between the single-vessel multilesion group (144 patients) and the multivessel group (104 patients). The 4.5-year probability of event-free survival was 68% and 70%, respectively, for the multilesion group and the multivessel group. In the event-free patients, 57% versus 59% were asymptomatic and 45% versus 46% were not taking antianginal drugs. In the anatomic subgroups, there were less event-free patients in the cohort of incompletely revascularized multivessel disease patients (55% of 55 patients) when compared with the cohort of those who were completely revascularized (84% of 79 patients) or when compared with the single-vessel disease multiple dilatation patients (74% of 107 patients). The 4.5-year event-free survival probability for each group was 44%, 78%, and 74%, respectively. This difference was caused by more infarctions (9% versus 2% versus 4%, respectively) and bypass operations in the multivessel disease, incomplete revascularization group (20% versus 5% versus 10%, respectively). In event-free patients, improvement of angina was similar and was documented in over 85% of patients in each group. Furthermore, the number of asymptomatic patients at follow-up was similar in all groups except that within the incomplete revascularization group, less patients were free of antianginal drugs (21% versus 51% versus 48%). Finally, 48% of the entire cohort performed an exercise test 4.6 months (mean) after dilatation and no difference was found in any of the variables in any group. About 10% of the patients experienced angina and approximately 30% had a positive exercise test for ischemia by ST segment criteria. The functional performance in every group was over 90% of the predicted work load. These results suggest that completeness of revascularization in multivessel disease patients is an important prognostic variable. However, the symptomatic improvement after dilatation is very rewarding in all subsets of patients and argues in favor of the continued use of multiple dilatations as a treatment strategy.

Prognostic significance of silent myocardial ischemia detected by early treadmill exercise after coronary angioplasty

Three hundred ninety patients who had successful coronary angioplasty were studied by treadmill exercise testing to determine the incidence and prognostic importance of silent and symptomatic myocardial ischemia in this patient subset. All patients were followed for an average of 11 months. During exercise, 81 patients (20%) had abnormal exercise-induced ST-segment depression without chest pain (group 1). Twenty patients (5%) had chest pain without ST changes (group 2). Twenty-one patients (5%) had both exercise-induced chest pain and ST-T-segment depression (group 3) and 268 patients (70%) had a normal exercise test with no chest pain (group 4). The groups were similar with respect to age, sex, history of previous myocardial infarct and previous coronary bypass surgery. Group 4 included more patients with complete revascularization. Mutually exclusive cardiac events were defined as cardiac death, nonfatal myocardial infarction, class III angina and additional revascularization (coronary angioplasty, coronary artery bypass surgery). The cardiac event rate in groups 1, 2 and 3 were significantly higher than in group 4 (40, 45 and 43 vs 22%; p = 0.001). There were 4 cardiac deaths and 4 nonfatal myocardial infarctions in group 1 compared to 2 cardiac deaths and 3 nonfatal myocardial infarctions in group 4 (p = 0.03 and 0.05, respectively). The event rates in groups 1, 2 and 3 patients with multivessel disease were significantly greater than in group 4 (44, 60 and 47 vs 22%; p = 0.002). Thus, exercise-induced myocardial ischemic episodes, both symptomatic and silent, early after coronary angioplasty are predictive of an unfavorable prognosis and serious cardiac events, particularly in patients with multivessel disease and incomplete revascularization.