Long-term prognostic importance of exercise echocardiography after an episode of unstable angina

Long-term Prognostic Value of Transesophageal Atrial Pacing Stress Echocardiography

OBJECTIVE

The aim of our study was to evaluate the long-term prognostic value of transesophageal atrial pacing stress echocardiography (TAPSE) for the prediction of cardiovascular events (myocardial infarction) and mortality at 10-year follow-up.

METHODS

TAPSE was applied as a diagnostic modality in 93 consecutive patients (mean age 45 +/- 8 years) who were diagnosed for the cause of chest pain. Long-term follow-up data were obtained from 87 (94%) patients with a mean duration of follow-up of 92 +/- 4 months. Stress echocardiography was performed using TAPSE with a mean pacing rate of 142 +/- 18/min.

RESULTS

Predefined cardiac events occurred during the follow-up period in 45 (52%) patients, including 24 (28%) with hard end points: 10 (12%) with nonfatal myocardial infarction and 17 who died (events overlap). Positive result of TAPSE was found in 47 (54%) patients and among those with positive TAPSE result, 16 died (94% of total mortality) and 21 had a hard event (death or infarction-88% of total prevalence). Survival free from hard events was noted in 37 (92%) patients with negative TAPSE and only in 26 (55%) of those with positive TAPSE ( P = .001). Independent predictive factors for mortality were TAPSE positivity (relative risk with 95% confidence interval [RR/CI] = 39.6 [36.3-42.9], P = .0006) and diabetes (RR/CI = 10.2 [8.6-11.8], P = .0026). Independent predictive factors for myocardial infarction were diabetes (RR/CI = 8.1 [6.3-9.9], P = .0186) and significant coronary stenosis in angiography (RR/CI = 9.0 [6.8-11.2], P = .0479). Independent predictive factors for death or nonfatal myocardial infarction were TAPSE positivity (RR/CI = 12.3 [11.1-13.3], P = .0001) and diabetes (RR/CI = 7.0 [5.8-8.2], P = .0018).

CONCLUSIONS

Positive TAPSE result carries long-term prognostic information regarding mortality and risk of myocardial infarction that can be used to identify patients requiring more aggressive treatment. Negative TAPSE allows highly accurate definition of low-risk population with discriminating power maintained during the 10-year period. TAPSE result and diabetes are the strongest independent predictors for long-term mortality in multivariate analysis.

Left atrioventricular plane displacement determined by echocardiography: a clinically useful, independent predictor of mortality in patients with stable coronary artery disease

BACKGROUND

Echocardiographically determined left atrioventricular plane displacement (AVPD) is strongly related to prognosis in patients with chronic heart failure and in postmyocardial infarction patients. We aimed at exploring whether AVPD, unlike ejection fraction, is related to mortality in patients with stable coronary artery disease (CAD).

METHODS AND RESULTS

Atrioventricular plane displacement was assessed by two dimensionally guided M-mode echocardiography in the four and two chamber views, in 333 consecutive patients with stable CAD and an abnormal coronary angiogram. Patients were followed up for an average of 41 months. AVPD was lower in patients who died (n= 30, 9.0 %) compared with survivors (9.0 +/- 2.2 vs. 11.5 +/- 2.1 mm, P<0.0001). Amongst patients with prior myocardial infarction (n=184) AVPD was 8.7 +/- 2.3 mm in those who died (n=17) and 11.2 +/- 2.3 mm in the survivors (P<0.0001). In patients without prior myocardial infarction (n=149), AVPD was 9.4 +/- 2.1 (n=13) and 11.8 +/- 1.8 mm, respectively (P<0.0001). Age, AVPD and four other echocardiographical variables correlated significantly with prognosis in univariate logistic regression analysis. In multiple logistic regression analysis only AVPD (P<0.0001) correlated independently with mortality.

CONCLUSION

Echocardiographically determined AVPDis a clinically useful, independent prognostic tool in patients with stable CAD. The presence of a documented previous myocardial infarction does not influence this observation.

Unstable angina pectoris and non-Q-wave myocardial infarction

Unstable angina pectoris and non-Q-wave myocardial infarction are clinical syndromes that share many pathophysiologic and clinical features. In the spectrum of coronary artery disease, these syndromes lie between chronic stable angina and Q-wave myocardial infarction. Although both conditions are associated with significant morbidity and mortality, patients presenting with these syndromes can be further risk stratified into higher and lower risk based on a number of readily available clinical features and biochemical parameters. Such risk stratification can allow for more tailored treatment and better resource allocation. Although routine early coronary angiography and revascularization has not been shown to be superior to conservative management, certain high-risk patients may benefit from a more aggressive strategy. Medical therapy with the use of antiplatelet, anticoagulant, and antiischemic agents remains the cornerstone of emergent treatment for patients presenting with these syndromes. The recent demonstration of a reduction in both morbidity and mortality with the glycoprotein IIb/IIIa antagonists has further expanded the armamentarium of available agents. Following initial stabilization, risk stratification with stress testing can help identify patients with a large residual ischemic burden who may benefit from coronary angiography with revascularization if feasible.

Dobutamine stress echocardiography and exercise electrocardiography for risk stratification in medically treated unstable angina

Previous reports have demonstrated the superiority of exercise echocardiography over exercise electro-cardiography (ex-ECG) for risk stratification in patients with medically stabilized unstable angina (UA). We sought to analyze the prognostic value of dobutamine stress echocardiography (DSE) compared with ex-ECG for risk stratification in patients with UA.

METHODS

Ninety-two patients with medically treated UA were studied (mean age 65 +/- 11 years, 24 women, 42% of patients had electrocardiographic abnormalities on admission). Dobutamine stress echocardiography and treadmill ex-ECG were performed on the third day after hospital admission. End points were recurrent UA, myocardial infarction (MI), or cardiac death.

RESULTS

Mean follow-up was 24 +/- 7 months. During follow-up, 22 patients had cardiac events (18 recurrent UA, 2 MI, 2 cardiac deaths). The event-free survival rate was 80% for patients with negative DSE results for ischemia and 52% for those with positive DSE results (log rank 9.57; P =.002), compared with an event-free survival rate of 79% for patients with negative ex-ECG results and 66% for those with positive ex-ECG results (log rank 2.06; P = not significant). Left ventricular dysfunction (P =.01) and a positive dobutamine stress echocardiogram (P =.03), but not a positive exercise electrocardiogram, were independent predictors of cardiac events during follow-up.

CONCLUSIONS

Dobutamine stress echocardiography performed early in medically treated patients with UA predicts cardiac events during follow-up more accurately and with more specificity than ex-ECG does in this population.

Long-Term Value of Stress Echocardiography in the Triage of Patients with Atypical Chest Pain Presenting to the Emergency Department

The purpose of this study was to assess the use of stress echocardiography in the triage of patients presenting to the emergency department with atypical chest pain. We hypothesized that a negative stress echocardiogram would identify patients with a very low risk for future cardiac events, thus reducing the requirement for unnecessary hospitalizations. Stress testing was performed in 105 patients presenting with atypical chest pain, no prior history of coronary artery disease, a nondiagnostic electrocardiogram (ECG), negative serial creatine phosphokinase level at 0 and 4 hours, and baseline normal echocardiograms. Cardiac stress was invoked using an exercise protocol in 75 (71%) patients and intravenous dobutamine in 30 (29%) patients, with ECG and echocardiography results analyzed separately. Cardiac events (myocardial infarction, coronary revascularization, and cardiac death) were noted in 7 (7%) patients with a mean follow-up of 2.8 +/- 1.3 years. Univariate analysis identified five predictors of future cardiac events, but only stress-induced wall motion abnormalities were found to be predictive with multivariate analysis. Kaplan-Meier estimate of cumulative event-free survival for cardiac events at 3 years was 99% for a negative stress echocardiogram (no stress-induced wall motion abnormalities) compared with 95% for stress ECG (< 1-mm ST segment depression). The event-free rate of a positive stress echocardiogram and stress ECG was 25% and 63%, respectively. We conclude that stress echocardiography can be performed safely in patients presenting with atypical chest pain. A negative stress echocardiogram carries an excellent 3-year prognosis and thus identifies patients who may forgo hospital admission and further cardiovascular workup.

Unstable angina and non-Q wave myocardial infarction: does the clinical diagnosis have therapeutic implications?

OBJECTIVES

The goal of this review is to reevaluate the unstable coronary syndromes in the setting of new therapies and biochemical markers.

BACKGROUND

Patients with acute coronary syndromes comprise a large subset of many cardiology practices. Patients with unstable angina (UA) and non-Q wave myocardial infarction (NQMI) may sustain a small amount of myocardial loss but have significant amounts of viable, yet ischemic, myocardium, placing them at high risk for future cardiac events. In the past, enzyme differentiation of NQMI from UA was considered important to assess prognosis and direct therapy.

METHODS

Manuscripts published in peer-reviewed journals over the past three decades were reviewed and selected for this review. Recent abstracts were also considered and cited where appropriate.

RESULTS

In the late 1990's, although UA and NQMI remain parts of a spectrum, it is apparent that the distinction between these two entities is no longer sufficient to identify high risk patients; rather, specific electrocardiographic changes, aspects of the clinical history, newer biochemical markers, and angiographic findings help to better distinguish higher risk individuals from a large patient population with unstable coronary syndromes and these factors usually determine therapy.

CONCLUSIONS

Based on these results, it is likely that newer therapies such as glycoprotein IIb/IIIa receptor antagonists, low molecular weight heparins, and coronary stents will be directed toward these high risk patients.

Utility of stress echocardiography in the triage of patients with atypical chest pain from the emergency department

We followed 108 patients presenting to the emergency department with atypical chest pain and triaged with stress echocardiography. One-year cardiac event-free survival was 100% with a negative stress echocardiogram and 25% with a positive study.

Stress Echocardiography: A Review of the Principles and Practice

Stress echocardiography, both pharmacologic and physiological, is an established noninvasive diagnostic method of detecting coronary artery disease. It also has a role in the assessment of patients with chest pain, the assessment of cardiovascular risk before noncardiac surgery, the assessment of patients after a myocardial infarction, the detection of viability in dysfunctional myocardium, and the prediction of functional recovery. The prognostic value of stress echocardiography is emerging. In this article, we discuss the methodology, diagnostic accuracy, and various clinical applications of stress echocardiography. We also review its limitations and compared it with other noninvasive methods of assessing patients with coronary artery disease.

Risk stratification of patients with medically treated unstable angina using exercise echocardiography

Functional testing is recommended for risk stratification of medically treated patients with unstable angina. Exercise echocardiography is used in this situation, but its safety and prognostic value are not well defined. The objective of this study was to assess the incremental prognostic value of exercise echocardiography in 226 consecutive patients (128 men, age 59+/-13 years) with medically treated unstable angina, who underwent exercise echocardiography from 1991 to 1996. Clinical risk was designated as low in 108 patients, intermediate in 116, and high in 2 patients according to the unstable angina practice guidelines. There were no major complications from the stress tests. The exercise electrocardiogram was nondiagnostic in 57 patients (25%). Ischemia was identified by exercise electrocardiography in 33 patients and exercise echocardiography in 55 patients. Patients were followed for 29+/-18 months. After exclusion of 38 patients who underwent early revascularization, 28 patients had cardiac death, nonfatal infarction, and late (>3 months) revascularization. Ischemia at exercise echocardiography was associated with a 24-month event-free survival of 81%, compared to 95% with negative exercise echocardiography (p=0.02). A positive exercise electrocardiogram was associated with a 24-month event-free survival of 84%, compared to 93% with negative exercise electrocardiograms (p=0.08). In a Cox regression model, event-free survival was predicted by ischemia at exercise echocardiography (relative risk 2.8, confidence interval: 1.3 to 6.3, p=0.05), but not at exercise electrocardiography (relative risk 2.1, confidence interval 0.7 to 5.8, p=0.16).

Prognostic value of stress echocardiography in the evaluation of atypical chest pain patients without known coronary artery disease

Patients with atypical chest pain frequently lack significant coronary artery disease (CAD) and are, therefore, at low risk for future adverse cardiovascular events. We hypothesized that in this group of patients, stress echocardiography could identify those at risk for cardiac events. We retrospectively reviewed (mean follow-up 23.0 +/- 7.2 months) the prognostic value of stress echocardiography for major (cardiac death, myocardial infarction, congestive heart failure, and unstable angina) and total (major events plus coronary revascularization) cardiac events in 661 patients with atypical chest pain, normal global left ventricular (LV) systolic function, and no history of CAD. A positive stress echocardiogram was defined as the development of new or worsening wall motion abnormalities with exercise stress (80%) or dobutamine (20%). A total of 41 cardiac and 16 major events were noted. The event-free survival for total cardiac events was 97% for a normal stress echocardiogram and 93% for a normal stress electrocardiogram (ECG) at 30 months. A positive stress ECG predicted an event-free rate of 86% compared with 74% for stress-induced wall motion abnormalities and 42% if stress-induced LV dysfunction accompanied the wall motion abnormalities. A strategy recommending invasive studies based on positive stress echocardiogram results increased the per-patient cost, but led to greater savings per cardiac event predicted and provided incremental prognostic value for future cardiac events beyond clinical and stress electrocardiographic data. Thus, stress echocardiography in low-risk patients for CAD appears to be more cost effective than a stress ECG.