Unstable angina: Relationship of clinical presentation,coronary artery pathology,and clinical outcome

Patients with unstable angina are heterogeneous with respect to presentation, coronary artery morphology, and clinical outcome. Subclassification of these patients based on clinical history has been proposed as a means of identifying individuals at increased cardiac risk. We applied such a classification system to 129 patients discharged from a coronary care unit with a diagnosis of acute myocardial ischemia. Patients were then assessed for cardiac events (recurrent angina requiring revascularization, myocardial infarction, death) 12 months following hospital discharge. Patients were classified as recent onset unstable angina preinfarction (n = 42), crescendo unstable angina preinfarction (n = 48), and unstable angina postinfarction (n = 39). Within each of these groups, the patients were further subclassified based on the occurrence of angina on effort, at rest, or both. No attempt was made to subset patients taking antiischemic drugs at the time of clinical presentation to the physician. Coronary angiographic pathology (morphology and number of vessels involved) was similar in the subgroups, but coronary artery thrombus was statistically more likely to be found in patients with crescendo rest angina preinfarction or with frequent anginal episodes at rest postinfarction. Mortality was significantly higher for patients with unstable angina postinfarction (7.7%) than preinfarction (1.1%). No statistical differences were noted between the subgroups with respect to the occurrence of myocardial infarction or recurrent unstable angina requiring revascularization. These data suggest that subclassification of unstable angina patients based on clinical characteristics at presentation is not useful to predict subsequent myocardial infarction or recurrent angina requiring revascularization. However, as one might expect, patients with recurrent angina postinfarction have a higher mortality rate than patients with unstable angina preinfarction, and patients with recurrent rest angina, either pre- or postinfarction, are more likely to have intracoronary thrombus than patients with new onset angina or crescendo effort angina; however, the presence of thrombus did not predict a poor clinical outcome.     

Different clinical and prognostic aspects of angina pectoris in unstable phase

The purpose of this study was to focus on the clinical and angiographic characteristics of 113 patients with crescendo angina (Group I) as compared to 187 patients with angina of new onset (Group II), selected from a series of 474 consecutive subjects, admitted to our clinic between January 1976 and July 1983 because of recurrent episodes of spontaneous angina, who underwent cardiac catheterization and coronary angiography within one month of hospitalization. Group I patients showed a greater incidence of prior transmural myocardial infarction (p less than 0.01), arterial hypertension (p less than 0.01), multivessel disease (p less than 0.01) and a lower value of left ventricular ejection fraction (p less than 0.01) than Group II patients. In the latter group of patients anginal episodes were more frequently associated with S-T segment elevation than with S-T segment depression (p less than 0.001), while the opposite was found in patients with crescendo angina. Survival curves up to five years showed that medically treated patients with crescendo angina had a worse long-term prognosis than patients with unstable angina of new onset (p less than 0.01). On the contrary no difference was found between the surgically treated patients of the two groups. Our data suggest that the more diffuse involvement of the coronary tree associated with a more depressed left ventricular function may result in an unfavorable long-term prognosis in patients with crescendo angina as compared to those with unstable angina of new onset. Such a difference between the two groups was abolished by surgical treatment.     

Coronary angioplasty in unstable angina. Immediate and short-term results

We report the results of percutaneous transluminal coronary angioplasty (PTCA) in 67 consecutive patients with unstable angina. Twenty patients had new onset (less than 2 months) angina, 33 patients had crescendo angina and 14 had early postinfarction angina. Fifty-one patients had one-vessel disease, 12 patients had two-vessel disease and two patients had three-vessel disease; two patients had a stenosis of a venous graft. In cases with multivessel disease, we performed only the dilatation of the ischaemia-related vessel identified by morphologic features of coronary lesion and electrocardiographic changes during chest pain. The procedure was successful in 54 cases (80.6%). Seven patients (10.4%) had major complications. Emergency coronary artery bypass graft surgery was performed in 6 cases (8.9%) because of occlusion of the left anterior descending artery; despite emergency operation one patient died and two patients sustained a myocardial infarction. One patient had occlusion of the right coronary artery and inferior myocardial infarction. In all patients in whom angioplasty was successful unstable angina disappeared. At 6 months follow-up there were no infarctions or deaths but 14 of 42 patients (33%) had recurrent angina. Restenosis occurred in 16 of 33 patients (48%) who had repeat coronary angiography. Four patients with recurrence of unstable angina had repeat angioplasty; it was successful in 3 cases. One patient died of refractory cardiac arrest. The mortality rate of 71 procedures performed in 67 patients was 2.8% (2/71) and the overall myocardial infarction rate was 4.2% (3/71).(ABSTRACT TRUNCATED AT 250 WORDS)     

Unstable angina: individualized stratification and prognosis.

OBJECTIVE: To analyse the methodology of risk stratification and the prognosis of patients admitted with unstable angina. POPULATION AND METHODS: This retrospective study involved a population of 68 patients (43 males and 25 females with a mean age of 65.8 +/- 9.8 years) consecutively admitted for suspected unstable angina during the year of 1996. Thirty six patients (52.9%) had angina at rest, 13 patients (19.1%) had both exertional and rest angina, 9 patients (13.2%) crescendo angina, 6 patients (8.8%) new onset exertional angina (less than 1 month), and 4 patients (5.8%) post-infarction angina (less than 2 weeks). The risk stratification was individualized. The coronary angiography (35 patients) was only performed when the medical therapy failed in patients with recurrent angina, or with proved ischemia after an exercise test and/or thallium 201 stress scintigraphy. Thirteen patients (19.1%) did not undergo these tests (advanced age and or bad general condition, or refusal). The follow-up of patients with and without ST-T changes was compared, as well as those revascularized versus non-revascularized. It was possible to achieve a mean follow-up of 13.7 +/- 6.2 months (3 to 25 months). RESULTS: The exercise test and/or thallium-201 stress scintigraphy were positive for myocardial ischemia in 28 pts (41.1%) and negative in 7 patients (10.2%). The coronary angiography revealed three-vessel coronary artery disease in 18 patients (26.4%), one vessel disease in 11 patients (16.1%) and two-vessel disease in 5 patients (7.3%). One patient had normal coronary arteries. Medical therapy was the initial approach. Coronary surgery was urgently performed in 3 patients and coronary angioplasty in 5 patients for refractory unstable angina. In the whole group coronary artery surgery was undertaken in 14 patients (20.5%) and coronary angioplasty in 12 patients (17.6%). A mean follow-up of 13.7 +/- 6.2 months was obtained in the 68 patients. During this period 6 patients (8.8%) died due to cardiac causes and 16 patients (23.5%) were readmitted: 8 patients (11.7%) for unstable angina, 5 patients (7.3%) for congestive heart failure and 3 patients (4.4%) for myocardial infarction. Fifty two patients (76.4%) remained free of cardiac events. The patients with transitory ST-T changes had more cardiac events (unstable angina, myocardial infarction, mortality) than the patients without ECG changes (13/30 vs 2/30, p = 0.003). When the revascularized patients were compared to the non revascularized no significant differences were observed regarding myocardial infarction and mortality, however revascularized pts had a less significant incidence of rehospitalization for unstable angina (0/26 vs 8/42 p = 0.02). CONCLUSIONS: An individualized strategy can be effective in pts with unstable angina. In this study 76.4% of patients remained free of cardiac events during the follow-up, 23.6% had severe cardiac events and the cardiac mortality was 8.8%. The patients with transitory ST-T changes had more cardiac events and worse prognosis. No patients significant difference was observed in the revascularized versus non revascularized patients for myocardial infarction and mortality; however, the revascularized patients had less significant incidence of rehospitalization for unstable angina.     

Prognostic significance of angina pectoris recurring soon after myocardial infarction

The prognostic significance of an early occurrence, or recurrence,of angina pectoris after myocardial infarction was studied in254 patients (221 male, 33 female; mean age 58±11 years).During the in-hospital rehabilitation program, 41 patients (16%)had anginal pain. The mean follow-up was 21 months (range 12–33months). Among the 254 patients, 21 died, five had recurrentmyocardial infarction, 13 had unstable angina, and 22 underwentaortocoronary bypass surgery. An early recurrence of anginapectoris was predictive of combined (medical+surgical) events(21 patients, P<0.05), medical events (11 patients, P<0.05)and surgical events (10 patients, P<0.001), but failed topredict individual death (six patients), recurrent myocardialinfarction (two patients) or unstable angina (three patients).Of the events that occurred in the 254 patients, 34% were predictedby the early recurrence of angina pectoris. Early post-infarctionangina was observed more frequently in older patients and patientswith previous history of angina pectoris. This represents animportant prognostic factor after myocardial infarction, whichdefines a high-risk group of patients requiring further investigationand appropriate therapeutic approaches.     

Angiographic morphology in unstable angina pectoris

Complex morphology occurs frequently in unstable angina; however, its relation to symptomatic presentation, timing of angiography and hospital outcome has not been investigated. Accordingly, coronary angiography was performed 5 +/- 2 days after qualifying rest pain in 101 consecutive patients presenting with acute coronary insufficiency (n = 67) or crescendo angina (n = 34). Significant coronary artery disease was defined as any greater than or equal to 50% stenosis, and complex morphology as any stenosis with irregularity, overhang or thrombus. Eight of the 67 patients presenting with acute coronary insufficiency later proved to have a myocardial infarction as the qualifying event (creatine kinase twice normal with elevation of MB fraction). There were no myocardial infarctions in the crescendo angina group. Complex morphology occurred in 61% of patients. Thrombus alone occurred in 27% of patients with unstable angina without myocardial infarction, with similar frequencies between the 2 clinical groups. In contrast, intraluminal thrombi were identified in 78% of patients with acute coronary insufficiency who later proved to have a myocardial infarction as the qualifying event. The need for urgent catheterization (less than 48 hours) prompted by recurrent symptoms was associated with the angiographic findings of intraluminal thrombus (46%) and complex morphology (83%). The presence of complex morphology and intracoronary thrombus was associated with a higher incidence of in-hospital cardiac events, i.e., revascularization, myocardial infarction and death, independent of the incidence of multivessel disease.     

Long-term prognosis of patients with early post-infarction angina.

BACKGROUND: Most studies have shown that early post-infarction angina (EPA) implies an unfavorable long-term prognosis among patients with acute myocardial infarction (AMI). However, some studies have failed to establish a link between the occurrence of EPA and increased mortality and recurrent infarction rates. METHODS AND RESULTS: In order to evaluate a long-term prognosis in patients with EPA, we assessed the 5-year prognosis of 80 patients with AMI by the presence or absence of EPA. During the 5-year follow up, the occurrence of death, cardiac death, recurrent infarction, unstable angina, heart failure, revascularization and cardiac events were recorded. A cardiac event was defined as an occurrence of any of the following events: cardiac death, recurrent infarction, unstable angina, heart failure and revascularization. Survival analysis showed no differences between patients with and without EPA in the probability of death (p=NS), cardiac death (p=NS), recurrent myocardial infarction (p=NS) and unstable angina (p=NS). Patients with EPA had a higher probability of developing cardiac events (p=0.0285) and undergoing revascularization procedures (p=0.0188). CONCLUSIONS: EPA increases the risk of patients developing cardiac events and undergoing revascularization procedures, and thereby implies a poor long-term prognosis for patients with AMI.     

Angiographic aspects of unstable angina

One-hundred and ninety-four patients with unstable angina pectoris (91 "in crescendo" angina and 103 new onset angina) underwent coronary angiography. The angiographic data from both groups were compared in order to discover whether angiographic aspects were related to the various clinical symptoms of coronary artery disease. Patients with recent onset angina had a significant increase (p less than 0.0001) of mono-vessel disease, whereas multi-vessel disease was prevalent in patients with "in crescendo" angina pectoris. Higher prevalence of coronary collaterals was observed in patients with "in crescendo" angina (p less than 0.005). No significant difference was observed in ejection fraction of the two groups. A further analysis was performed in 100 patients with unstable angina pectoris but without prior myocardial infarction (42 "in crescendo" angina and 58 recent onset angina). Also in these patients were found the same results; with the exception of ejection fraction which was more slight in patients with "in crescendo" angina (p less than 0.01). These data confirm that patients with unstable angina are an heterogeneous group in which comparison is unreliable and that the severity of clinical symptoms is not related to the degree of angiographic coronary lesions.     

Comparison of clinical features of non-Q wave and Q wave myocardial infarction

The clinical spectrum and outcome of 119 patients with acute non-Q wave myocardial infarction (NQMI) were studied, in comparison with those of 354 patients with acute Q wave myocardial infarction (QMI). The patients with NQMI had a significantly higher incidence of preinfarction angina (73% vs 63%), previous myocardial infarction (43% vs 22%), multivessel disease (73% vs 51%), postinfarction angina (55% vs 21%), and recurrent myocardial infarction during follow-up for an average of 25 months (17% vs 8%). NQMI patients also had a lower rate of complication of pump failure and smaller infarct size estimated by peak creating phosphokinase (CPK) levels (1361 +/- 1243 vs 2711 +/- 1684 IU/L) than those with QMI. There was no difference in in-hospital mortality between the two groups (17% vs 17%). However, death due to cardiac rupture was exclusively noted in the QMI group. The present study suggests that NQMI is more unstable than QMI in the clinical course.     

Usefulness of hospital admission risk stratification for predicting nonfatal acute myocardial infarction or death six months later in unstable angina pectoris. RESCATE Study Group. Resources Used in Acute Coronary Syndromes and Delays in Treatment

The aim of this study was to assess the clinical course of unstable angina and the prognostic value of clinical and electrocardiographic variables measured during admission in a prospective, multicenter cohort study with 6-month follow-up. The population corresponds to 4 general teaching hospitals in Catalonia, Spain. The clinical course was analyzed in 839 consecutive patients aged up to 80 years with primary unstable angina, without myocardial infarction or previous coronary bypass. The main outcome measures were cardiac mortality and nonfatal myocardial infarction. Patients involved in the present analysis belonged to the Resources Used in Acute Coronary Syndromes and Delays in Treatment (RESCATE) study. Six-month overall mortality, cardiac mortality, and nonfatal myocardial infarction rates were 4.6%, 4.1%, and 3.9%, respectively. Six-month cardiac mortality or myocardial infarction rate did not differ among clinical forms of presentation. Peripheral artery disease (RR 3.5, 95% confidence interval [CI] 1.88 to 6.50, p = 0.0001), ST-T-wave electrocardiographic changes on admission (RR 2.22, 95% CI 1.13 to 4.36, p = 0.0203), and age >65 years (RR 1.74, 95% CI 1.04 to 2.91, p = 0.0356) independently predicted 6-month cardiac mortality or nonfatal myocardial infarction. Their positive predictive values were 21%, 10%, and 11%, respectively, whereas their negative predictive value was > or = 93% in all cases. Prevalences were 9%, 70%, and 41%, respectively. In this prospective study, patients with unstable angina without prior myocardial infarction have a relatively low, although not negligible, 6-month severe complication rate. Stratification risk can easily be established with clinical and electrocardiographic characteristics measured during admission. Their absence almost rules out future adverse events, while their presence does not necessarily imply bad prognosis.     

Feasibility and prognostic value of dobutamine-atropine stress echocardiography early in unstable angina.

BACKGROUND AND AIM: Because unstable angina has always been considered a contraindication for dobutamine-atropine stress echocardiography (DSE), the role of dobutamine-atropine stress echocardiography in unstable angina is unknown. Our aim was to assess the safety and prognostic value of dobutamine-atropine stress echocardiography in unstable angina. METHODS: One hundred and thirty-two patients were studied (mean age 64+/-12 years, 29 women). Dobutamine-atropine stress echocardiography was performed on the third day after hospital admission. End-points were unstable angina, myocardial infarction or cardiac death at 1 year follow-up. RESULTS: No major complications occurred during dobutamine-atropine stress echocardiography. Ninety-six (78%) patients were on beta-blocker therapy during the test; mean maximum heart rate achieved was 106+/-23 beats x min(-1). Nine of the 21 patients (43%) with a positive dobutamine-atropine stress echocardiography presented cardiac events during follow-up: two patients died, one had a myocardial infarction and six had recurrent class III-IV angina. Among 80 patients with negative dobutamine-atropine stress echocardiography, one (1%) had myocardial infarction and six patients (7.5%) had recurrent angina. Event-free survival after 1 year for patients with a negative dobutamine-atropine stress echocardiography for ischaemia was 91% compared to 57% for those with a positive dobutamine-atropine stress echocardiography (P<0. 0001). Left ventricular dysfunction (P=0.01), prior myocardial infarction (P=0.03) and a positive dobutamine-atropine stress echocardiography (P=0.004) were independent predictors of cardiac events during follow-up. CONCLUSIONS: Dobutamine-atropine stress echocardiography is safe in unstable angina if it is performed when patients remain asymptomatic for at least 48 h. A negative dobutamine-atropine stress echocardiogram for ischaemia predicts a good prognosis in medically treated patients with unstable angina and may allow their early discharge from hospital. Good prognostic information was obtained despite the use of beta-blockers and low heart rates during dobutamine-atropine stress echocardiography.     

Long-term prognosis in unstable angina. The importance of early risk stratification using continuous ST segment monitoring

Aims To assess the ability of clinical characteristics, ad-missionECG and continuous ST segment monitoring in determining long-termprognosis in unstable angina. Methods Two hundred and twelve patients with unstable angina (mean age59 years), presenting within 24h of an acute episode of anginawere recruited at three hospitals and treated with standardizedmedical therapy. All patients kept chest pain charts and underwentST segment monitoring for 48h. The occurrence of death, myocardialinfarction, and need for revascularization was assessed overa median follow-up of 2·6 years. Results The risk of death of myocardial infarction was greatest in thefirst 6–8 weeks after admission. Admission ECG ST depressionand the presence of transient ischaemia predicted increasedrisk of subsequent death or myocardial infarction, whereas anormal ECG predicted a good prognosis. In 14 patients, ST segmentmonitoring provided the only evidence of recurrent ischaemia,and 72% of this group suffered an adverse event. Transient ischaemiaand a history of hypertension were the most powerful independentpredictors of death or myocardial infarction. Conclusions Adverse events in unstable angina occur early after admissionand can be predicted by clinical and ECG characteristics, andby the presence of transient ischaemia during ST segment monitoring.Risk stratifi-cation by these simple assessments can identifypatients with unstable angina at high risk.     

Clinical characteristics of unstable angina in 162 consecutive cases

We surveyed the clinical characteristics, treatment, and prognosis of 162 patients with unstable angina, who were admitted to our center between 1985 and 1987. There were 112 males and 50 females, with a mean age of 65 years. The clinical characteristics according to the American Heart Association classification were new angina of effort in 21%, changing pattern in 61%, and new angina at rest in 18% of the patients. ECG recordings during attacks of angina were obtained in 70%, and ST elevation was detected in 11%, ST depression in 54%, and T wave abnormality in 5%. Coronary arteriography performed in 42% of the patients revealed single vessel lesion in 21%, two vessel lesion in 10%, three vessel lesion in 5%, and left main trunk lesion in 3% of the patients. Seventy-seven percent of the patients were controlled by medical therapy, including nitrates, calcium antagonists, and, in some cases, beta blockades. Three percent of the patients were controlled with intra aortic balloon pumping in addition to medical therapy. Coronary artery bypass graft surgery (CABG) was performed in 6% of the patients. Since 1987, percutaneous transluminal angioplasty (PTCA) was introduced in our center and PTCA was performed in 9 patients (6%). Restenosis of the dilated portions of the coronary artery was observed and PTCA was again performed in 2 of 9 patients (22%). All patients who received CABG or PTCA survived and have been free from angina or myocardial infarction. Non-fatal myocardial infarction occurred in 10 cases (5.6%) and fatal infarction occurred in one patient (0.6%).     

Risk stratification after acute myocardial infarction by means of exercise two-dimensional echocardiography

To determine whether exercise two-dimensional echocardiography contributes to the prognostic information provided by exercise testing in patients recovering from acute myocardial infarction, 40 patients were prospectively studied by means of pre- and postexercise echocardiography 10 to 21 days after myocardial infarction. Patients were followed for 6 to 10 months or until one of the following clinical end points occurred: death, recurrent myocardial infarction, unstable angina, or coronary artery bypass grafting. Results of treadmill exercise tests were negative in 13 of 20 patients with good clinical outcome (65% specificity) and positive in 11 of 20 patients with poor clinical outcome (55% sensitivity). The resting echocardiogram was abnormal in 37 of 40 patients. The exercise echocardiogram was negative in 19 of 20 patients with good clinical outcome (95% specificity) and positive in 16 of 20 patients with poor clinical outcome (80% sensitivity). We conclude that exercise echocardiography is more sensitive and specific than treadmill exercise testing for predicting the occurrence of subsequent cardiac events after acute myocardial infarction.     

Unstable angina: from physiopathology to therapeutics]

Unstable angina is a term which encompasses several clinical syndromes (crescendo angina, angina de novo, resting angina, postinfarction angina), intermediary between stable angina and myocardial infarction. The results of coronary angioscopy have allowed differentiation of accelerated effort angina which seems related to ulceration of an atheromatous plaque from resting angina, more commonly associated with intraluminal thrombosis. The diagnosis of unstable angina is clinical and justifies immediate hospital admission to a coronary care unit because of the risk of myocardial infarction and/or sudden death. Medical management comprises triple anti-ischemic therapy (nitrate derivatives, betablockers, calcium antagonists), anticoagulants and platelet antiagregants. Randomised therapeutic trials versus placebo have shown that this treatment decreases the incidence of refractory angina and myocardial infarction. Several studies are under way to assess the role of thrombolytic therapy in unstable angina. When unstable angina is refractory to maximal medical therapy, emergency coronary angiography should be performed. However the outcome is usually favourable and coronary angiography can be performed several days after the acute event. The coronary lesion responsible for unstable angina is often "complex", an eccentric, irregular, severe stenosis or appearances of thrombosis. Whenever possible, depending on the coronary lesion, myocardial revascularisation by coronary angioplasty or aorto-coronary bypass should be proposed. Surgical treatment has been shown to be more effective (symptomatic relief, improved survival) than medical therapy in patients with triple vessel disease. However, the results of studies comparing medical or surgical treatment with coronary angioplasty are not yet available.     

Prognostic significance of a predischarge exercise test in risk stratification after unstable angina pectoris

The prognostic significance of exercise testing was compared with clinical and electrocardiographic (ECG) variables in a prospective study of 107 patients with unstable angina discharged from the hospital on medical therapy. During a follow-up period of 12.8 +/- 1.4 months, 10 patients (9%) had a nonfatal myocardial infarction (n = 8) or died (n = 2) and 22 (20%) were readmitted with recurrent unstable angina. The relation between 20 clinical, ECG and exercise test variables and the risk of adverse outcome (death, nonfatal myocardial infarction or recurrent unstable angina) was analyzed using both univariate and multivariate (logistic regression) analysis. Univariate predictors of adverse outcome included diabetes mellitus, evolutionary T wave changes, T wave changes on the preexercise ECG and low maximal rate-pressure product during exercise. Independent predictors of adverse outcome in multivariate analysis included diabetes mellitus, evolutionary T wave changes after admission, rest pain during hospitalization, ST depression during exercise and low maximal rate-pressure product. A predictive model constructed using the regression equation and all independent predictors stratified patients into high and low risk groups (41% and 5% risk of adverse outcome, respectively). The result of a predischarge exercise test adds independent prognostic information to clinical and ECG data in medically treated patients with unstable angina and could be used in combination with clinical and ECG data to identify patients at risk of adverse events.     

Effects of preceding stable or unstable angina on hospital morbidity-mortality of myocardial infarction. Results of a continuous series of 1,910 patients

The aim of this study was to determine the effect of preceding unstable angina on the short-term prognosis of myocardial infarction based on early complications: cardiac failure, cardiac rupture, ventricular septal defect, sustained ventricular tachycardia ventricular fibrillation and hospital mortality. A continuous series of 1,910 patients admitted with 7 days of myocardial infarction was analysed retrospectively. The patients were divided into two groups according to their previous coronary history: Group A (myocardial infarction preceded by unstable angina) and Group B (myocardial infarction without preceding unstable angina). Group B was subdivided into Group B1 (myocardial infarction de novo) and Group B2 (myocardial infarction with previous stable angina). The results showed that patients with previous unstable angina (Group A) had a lower hospital mortality (7.9%) than those without (Group B) (13.3%) (p = 00017), fewer cardiac ruptures (1.1 versus 2.9%, p = 0.03) and less ventricular fibrillation (2.6 versus 4.5%, p = 0.053). Subgroups analysis showed that patients with de novo myocardial infarction (Group B1) had more sustained ventricular tachycardia than those with previous stable angina (Group B2) (5.3 versus 2.7%, p = 0.04). The authors conclude that pre-infarction unstable angina, possibly by ischaemic pre-conditioning, is an independent factor of a better prognosis in myocardial infarction.     

Reassessment of treadmill stress testing for risk stratification in patients with acute myocardial infarction treated by thrombolysis.

OBJECTIVES--To evaluate the role of a treadmill stress test for identifying patients at risk of recurrent ischaemic events after acute myocardial infarction treated by thrombolysis. BACKGROUND--The natural history of myocardial infarction has changed with the introduction of thrombolytic treatment; there is a lower mortality but a higher incidence of recurrent thrombotic events (reinfarction, unstable angina). The treadmill stress continues to be recommended for risk stratification after acute myocardial infarction even though its value has never been formally reassessed in the thrombolytic era. METHODS--Prospective observational study in which 256 consecutive patients who presented with acute myocardial infarction treated by thrombolysis underwent an early treadmill stress test and were followed up for 10 (range 6-12) months. RESULTS--Recurrent ischaemic events occurred in 41 patients (unstable angina 15, reinfarction 21, death five) and a further 21 required revascularisation. Both ST depression at a low workload and low exercise tolerance (< 7 metabolic equivalents of the task (METS) were predictive of recurrent events, with respective hazard ratios of 1.93 (95% confidence interval (95% CI) 1.17-3.20; p < 0.01)) and 1.67 (95% CI 1.0-2.78; p < 0.05). These variables identified 50% and 70% of patients who subsequently sustained a recurrent ischaemic event, but the corresponding values for positive predictive accuracy were only 26% and 21%. Thus they are of limited value as a screening measure for identifying patients likely to benefit from invasive investigation and revascularisation. None of the other variables (ST elevation, haemodynamic responses, ventricular extrasystoles, angina) was significantly associated with recurrent ischaemic events. CONCLUSIONS--The treadmill stress test is of limited value for identifying patients at risk of recurrent ischaemic events after acute myocardial infarction treated by thrombolysis.     

Irregular coronary lesion morphology after thrombolysis predicts early clinical instability.

After successful thrombolytic treatment for acute myocardial infarction, recurrent ischemia and infarction may occur with little warning. Coronary lesion morphology was analyzed from angiograms performed in 72 consecutive patients at 1 to 8 days after streptokinase treatment for acute myocardial infarction and the data were evaluated in relation to the subsequent clinical course. All patients were clinically stable at the time of angiography and continued to receive heparin infusion for greater than or equal to 4 days after thrombolysis. The infarct-related artery was patent in 55 patients (76%). In the 10 days after angiography, 15 patients developed prolonged episodes of angina at rest; the condition of 4 stabilized with medical treatment, but 11 required urgent medical intervention (coronary angioplasty in 8 and bypass surgery in 3). There were no differences in age, gender, left ventricular function or extent of coronary artery disease between those patients who developed unstable angina and those who had a stable in-hospital course. However, the median plaque ulceration index of the infarct-related lesion was 6.7 (95% confidence limits 6.3, 10) in the 15 patients with an unstable course versus 3.3 (2, 4.4) in those with a stable course (p less than 0.001). There were no differences between the two patient groups in the severity of stenosis, length of diseased segment, symmetry/eccentricity, presence of a shoulder, location at branch point or bend, presence of globular or linear filling defects, contrast staining or collateral supply. These data show that after thrombolysis, the degree of irregularity of the infarct-related artery is a critical determinant of early clinical instability.(ABSTRACT TRUNCATED AT 250 WORDS)     

Unstable Angina: Good Long-Term Outcome After a Complicated Early Course

Objectives. This study was performed to investigate the long-term outcome of patients with unstable angina within subgroups of the Braunwald classification.

Background. Long-term follow-up studies of patients with unstable angina are rare and date from more than two decades ago. This study was performed to establish the prognosis of different subgroups of patients with unstable angina (Braunwald criteria) during a 7-year follow-up period.

Methods. We registered a well defined group of 417 consecutive patients, admitted to the hospital for suspected unstable angina. The definite diagnosis was unstable angina in 282 patients (68%) and evolving myocardial infarction in 26; in 109 patients (26%), the symptoms were attributed to other or nonspecific causes. Patients with definite unstable angina were subclassified according to the Braunwald classification. Survival, survival without infarction and survival without infarction or intervention were determined for each class.

Results. After a median follow-up period of 94 months, the mortality rate in the first year was 6% and 2% to 3% in the following years. The frequency of revascularization was 47% in the first year, and that for myocardial infarction was 11% in the first year and 1% to 3% thereafter. The Braunwald classification appeared to be appropriate for risk stratification in the first year. However, at 7 years the event rates in all classes were similar. In particular, the Braunwald classification had no long-term impact on mortality or infarction rates. However, patients with acute angina at rest or postinfarction angina and patients with extensive anginal treatment had high intervention rates.

Conclusions. To our knowledge, this study is the first to demonstrate that despite a complicated course during the first year, current management results in good long-term outcome in patients with unstable angina.