Identification of unstable angina patients who have favorable outcome with medical or surgical therapy (eight-year follow-up of the Veterans Administration Cooperative Study)

Predictors of long-term mortality after hospitalization for primary unstable angina pectoris and non-ST-elevation myocardial infarction

Data are sparse regarding long-term outcomes after hospitalization for unstable angina pectoris (UAP) and non-ST-elevation myocardial infarction (NSTEMI), as defined by contemporary criteria. We extended follow-up in a preexisting database of unselected patients with primary UAP and NSTEMI admitted by way of the emergency department from 1991 to 1992. Stepwise Cox models were used to identify multivariate predictors of long-term mortality. There were 275 patients (mean age 66 +/- 12 years, 33% women) who survived to hospital discharge; 134 patients (49%) died during follow-up (median 9.4 years). Significant multivariate predictors of long-term mortality were: age (hazard ratio [HR] per decade 1.7, 95% confidence interval [CI] 1.4 to 1.9); prior MI (HR 1.7, 95% CI 1.2 to 2.5); diabetes (HR 1.7, 95% CI 1.2 to 2.4); congestive heart failure (HR 2.2, 95% CI 1.5 to 3.4); elevated creatinine (HR 2.5, 95% CI 1.7 to 3.8); elevated leukocyte count (HR 1.7, 95% CI 1.1 to 2.5); systolic blood pressure <120 mm Hg at presentation (HR 2.0, 95% CI 1.1 to 3.6); lack of coronary revascularization during the index hospitalization (HR 2.0, 95% CI 1.3 to 3.0); and lack of discharge beta-blocker therapy (HR 1.5, 95% CI 1.1 to 2.2). A clinical prediction rule was generated by assigning weighted point scores for the presence of each significant covariate. Long-term mortality increased markedly with each quintile of score; for quintiles 1 to 5, mortality rates were 8.5%, 29.4%, 47.6%, 75.0%, and 91.5%, respectively (p value for trend <0.001). These data are among the first assessments of long-term mortality after hospitalization for primary UAP and NSTEMI, as defined by contemporary guideline criteria. Easily obtained clinical covariates provide excellent prediction of long-term mortality up to 10 years after hospitalization for primary UAP and NSTEMI.

Mechanisms behind the prognostic value of troponin T in unstable coronary artery disease: a FRISC II substudy

OBJECTIVES

This study was designed to elucidate possible mechanisms for the prognostic value of troponin T (tnT).

BACKGROUND

The reasons for the adverse prognosis associated with elevation of troponins in unstable coronary artery disease are poorly understood.

METHODS

Patients enrolled in the Fast Revascularization during InStability in CAD (FRISC-II) trial were included. Clinical characteristics, findings at echocardiography and coronary angiography, and prognosis were evaluated in relation to different tnT levels.

RESULTS

Absence of significant coronary stenosis was more frequent and three-vessel disease or left main stem stenosis was less frequent in patients without, compared with, detectable tnT. The occurrence of visible thrombus increased with rising levels of tnT. In the group with the highest levels of tnT, occlusion of the left circumflex artery was more common than in the three other tnT groups, as was a left ventricular ejection fraction below 0.45. The one-year risk of death in the noninvasive arm of the study increased by increasing levels of tnT (1.6% to 4.6%), whereas the risk of myocardial infarction showed an inverted U-shaped curve and was lower in the lowest (5.5%) and highest (8.4%) tnT groups than in the two intermediate groups (17.5% and 16.2%).

CONCLUSIONS

Any detectable elevation of tnT raises the probability of significant coronary stenosis and thrombus formation and is associated with an increased risk of reinfarction and death. However, at a more pronounced elevation of troponin, a higher proportion of patients has a persistent occlusion of the culprit vessel and reduced left ventricular function, associated with a high mortality but a modest risk of reinfarction.

[Prognostic value of cardiac perfusion scintigraphy associated with the dobutamine test in acute coronary syndromes]

OBJECTIVES

This study aimed to establish the value of myocardial ischemia induced by the dobutamine infusion test associated to 99m technetium isonitrile single photon emission computed tomography in patients with unstable angina or non Q-wave infarction during the first days in the Coronary Care Unit.

METHODS

Fifty three patients with unstable coronary syndromes and common medical treatment were studied with a moderate-dose dobutamine test (5 to 20 microgram/Kg/min) using a 99mTc-MIBI SPECT. The results were correlated with the incidence of recurrent angina, infarction, death or revascularization.

RESULTS

The dobutamine test induced a reversible perfusion defect in 36 patients (68%) and angina in 12 of them (12/36, 33%). However, the patients who had a positive test had a similar incidence of events as those with a negative test (58% vs 59%). Thus, while the sensitivity of the dobutamine test to identify patients at risk was relatively high (68%), its specificity (32%) and its negative predictive value (41%) were low. The patients with dobutamine-induced angina, however, had a higher scintigraphy score (3.0 +/- 1,7 vs 1.6 +/- 1.8, p < 0.02) and a higher incidence of recurrent angina (8/12, 67% vs 13/41, 31%, p < 0.04) than those without, at a comparable double product.

CONCLUSIONS

In conventionally treated patients with unstable coronary syndromes, the specificity of the inducible scintigraphic ischemia with moderate dose of dobutamine performed during the first days is too low to be used as a marker for in-hospital events. However, inducible angina with dobutamine suggests an extensive jeopardized area and/or a particularly reduced ischemic threshold.

[The practical clinical guidelines of the Sociedad Española de Cardiología on coronary surgery]

Surgery in coronary disease, including myocardial revascularization and the surgery of mechanical complications of acute myocardial infarction, has shown to improve the symptoms, quality of life and/or prognosis in certain groups of patients. The expected benefit in each patient depend on many well-known factors among which the appropriateness of the indication for surgery is fundamental. The objective of these guidelines is to review current indications for cardiac surgery in patients with coronary heart disease through an evaluation of the degree of evidence of effectiveness in the light of current knowledge (systematic review of bibliography) and expert opinion gathered from various reports. Indications and the degree of recommendation for conventional coronary artery bypass grafting have been established for each of the most frequent anatomo-clinical situations defined by clinical symptoms (stable angina, unstable angina and acute myocardial infarction) as well as by left ventricular function and extend of coronary disease. Furthermore, the subgroups with the greatest surgical risk and stratification models are described to aid the decision making process. Also we analyse the rational basis and indication for the new surgical techniques such as minimally invasive coronary surgery and total arterial revascularization. Finally, the indication and timing of surgery in patients with mechanical complications of acute myocardial infarction are considered.

The future: screening and effective intervention

Despite an increased understanding of risk factors for cardiovascular disease and the development of new programs, procedures, and medications to reduce risk, effective large-scale primary and secondary prevention have remained difficult to achieve. Large-scale, primarily educational, community-based programs aimed at detecting and reducing risk can be effective, particularly when they are aimed at specific populations at increased risk. However, the long-term benefits of these programs have been modest. Recent studies have demonstrated that lipid-lowering therapy is a critical adjunct to dietary and lifestyle changes. The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors in particular are highly effective in reducing cardiovascular risk in both primary and secondary prevention programs that combine lifestyle modification and aggressive medical therapy. The ability of these drugs to produce rapid improvements in endothelial function and increase coronary perfusion also supports their use in the medical rather than surgical management of at least some patients with cardiovascular disease who are candidates for percutaneous transluminal coronary angioplasty.

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.