Exercise versus recovery electrocardiography for predicting outcome in hypertensive patients with chest pain

Recovery of rate-pressure product and cardiac mortality in coronary artery disease patients with type 2 diabetes

AIMS

To investigate prognostic significance of post-exercise recovery of rate-pressure product (RPP) in patients with stable coronary artery disease (CAD) and type 2 diabetes (T2D).

METHODS

Patients with angiographically documented CAD and T2D (n = 697) underwent symptom-limited bicycle exercise test. Exercise capacity (EC), heart rate, blood pressure and RPP responses to peak exercise and recovery (2' and 5' after cessation of exercise) were analyzed. Cardiac death was the primary and sudden cardiac death (SCD) secondary endpoint.

RESULTS

During a median follow-up of 76 months, 49 cardiac deaths (7.0%) and 28 SCDs (4.0%) were observed. The recovery of RPP at 5' was the strongest univariate predictor of cardiac death (hazard ratio [HR]: 2.55 per SD decrease, 95%CI: 1.82-3.58, p < 0.001) and SCD (HR: 2.34, 95%CI: 1.51-3.62, p < 0.001). In multivariate analysis, it remained significantly associated to cardiac death and SCD without (HR: 1.66, 95%CI: 1.14-2.41, p < 0.01 and HR: 1.75, 95%CI: 1.08-2.85, p < 0.05, respectively) and with additional adjustment for EC and peak RPP (HR: 1.45, 95%CI: 1.09-1.92, p < 0.05 and HR: 1.52, 95%CI: 1.01-2.27, p < 0.05, respectively).

CONCLUSIONS

The recovery of RPP after exercise is a potent predictor of cardiac death in patients with CAD and T2D. It provides significant prognostic information beyond EC and peak RPP.

Maximal exercise electrocardiographic responses and coronary heart disease mortality among men with metabolic syndrome

OBJECTIVE

To examine the association between abnormal exercise electrocardiographic (E-ECG) test results and mortality (all-cause and that resulting from coronary heart disease [CHD] or cardiovascular disease [CVD]) in a large population of asymptomatic men with metabolic syndrome (MetS).

PATIENTS AND METHODS

A total of 9191 men (mean age, 46.9 years) met the criteria of having MetS. All completed a maximal E-ECG treadmill test (May 14, 1979, through April 9, 2001) and were without a previous CVD event or diabetes at baseline. Main outcomes were all-cause mortality, mortality due to CHD, and mortality due to CVD. Cox regression analysis was used to quantify the mortality risk according to E-ECG responses.

RESULTS

During a follow-up of 14 years, 633 deaths (242 CVD and 150 CHD) were identified. Mortality rates and hazard ratios (HRs) across E-ECG responses were the following: for all-cause mortality: HR, 1.36; 95% confidence interval (CI), 1.09-1.70 for equivocal responses and HR, 1.41; 95% CI, 1.12-1.77 for abnormal responses (P(trend)<.001); for mortality due to CVD: HR, 1.29; 95% CI, 0.88-1.88 for equivocal responses and HR, 2.04; 95% CI, 1.46-2.84 for abnormal responses (P(trend)<.001); and for mortality due to CHD: HR, 1.62; 95% CI, 1.02-2.56 for equivocal responses and HR, 2.45; 95% CI, 1.62-3.69 for abnormal responses (P(trend)<.001). A positive gradient for CHD, CVD, and all-cause mortality rates across E-ECG categories within 3, 4, or 5 MetS components was observed (P<.001 for all).

CONCLUSION

Among men with MetS, an abnormal E-ECG response was associated with higher risk of all-cause, CVD, and CHD mortality. These findings underscore the importance of E-ECG tests to identify men with MetS who are at risk of dying.

Noninvasive techniques to assess myocardial ischemia in hypertensive patients

Hypertensive patients are more affected by coronary artery disease (CAD) than normotensive patients. Currently, established techniques are able to diagnose myocardial ischemia/CAD in hypertensive patients with suspected CAD. An irrevocable role remains for exercise electrocardiogram (ECG) owing to the many parameters evaluated under physiologic conditions. However, the suboptimal specificity of a positive exercise ECG demands further examination of hypertensive patients with either myocardial single-photon emission computed tomography (SPECT) or stress echocardiography, both more specific than exercise ECG in diagnosing CAD. The high specificity of imaging techniques also makes them highly predictive of cardiac events. Additional techniques to help diagnose CAD are available. Tissue Doppler imaging, strain and other echo-derived techniques may add quantitative elements to recognize CAD in hypertensive hearts. The accuracy of MRI is improving to study myocardial function and perfusion. Positron emission tomography and multislice computed tomography, also in-built with fusion scanners, are playing roles in combining coronary angiography and myocardial function/ischemia assessment. However, no significant application of these additional techniques is available for hypertensive patients. Epicardial CAD assessed by coronary angiography remains the gold standard to decide for revascularization procedures. The presence of microcirculatory dysfunction, a symptom typical of hypertensive hearts, is opening up new areas of noninvasive diagnostic techniques for the detection of coronary flow reserve (CFR) and related myocardial ischemia. The quantification of CFR may render this parameter pivotal to deciding the need for revascularization procedures of intermediate coronary stenosis and it may become an additional gold standard in evaluating coronary vessels. Moreover, even with normal epicardial coronary arteries, microcirculation dysfunction bears prognostic stratification capabilities for hypertensive patients and it may become a promising therapeutic target in the near future.

The Stress-Recovery Index for the risk stratification of women with typical chest pain

AIM

To prospectively assess the prognostic value of the Stress-Recovery Index (SRI) in women with typical chest pain.

METHODS

165 women without known coronary artery disease, who complained of typical chest pain, were exercise tested and prospectively followed-up for the occurrence of cardiac death and nonfatal myocardial infarction. SRI, defined as the difference in absolute values between the area of heart rate-adjusted ST-segment depression during exercise and recovery, was derived in all. Clinical data, resting ejection fraction, and exercise testing data were entered into a sequential Cox's model; SRI was entered last. Model validation was performed by bootstrap adjusted by the degree of optimism in estimates. Survival curves were set up using Kaplan-Meier method and compared by the log-rank test.

RESULTS

During a median follow-up time of 42 months, 19 events (14 cardiac deaths and 5 nonfatal myocardial infarction) were observed. Age (hazard ratio 3.58, 95% CI 0.87-15) and SRI (hazard ratio 0.62, 95% CI 0.42-0.92) were multivariate predictors of outcome. However, the addition of SRI increased the prognostic power of the model on top of clinical and exercise testing variables, as demonstrated by the significant (p=0.003) increase of the area under the ROC curve of the risk function. Survival analysis showed ascending SRI quartiles to identify a significant (p=0.005) increase in event-free survival.

CONCLUSIONS

SRI is of value in predicting outcome of women with typical chest pain and provides additional prognostic information on the top of clinical and standard exercise testing data.

Comparison of the prognostic value of the stress-recovery index versus standard electrocardiographic criteria in patients with a negative exercise electrocardiogram

To verify whether the stress recovery index (SRI) improves risk stratification in patients with a negative exercise electrocardiogram (ECG) using standard criteria, the SRI was derived in 708 consecutive patients with a negative exercise ECG. All-cause mortality and the combination of death or nonfatal myocardial infarction were target end points. The individual effect of clinical and exercise testing data on outcome was evaluated using Cox regression analysis with separate models for each group of variables. Model validation was performed using bootstrap adjusted by degree of optimism in estimates. Survival analysis was performed using a product-limit Kaplan-Meier method. During a 37-month follow-up, 22 deaths and 40 nonfatal acute coronary syndromes occurred. After adjusting for confounding variables, age (hazard ratio 1.62, 95% confidence interval [CI] 1.14 to 2.31 for interquartile difference), hypertension (hazard ratio 1.74, 95% CI 1.04 to 2.89), and SRI (hazard ratio 0.75, 95% CI 0.65 to 0.86 for interquartile difference) were predictive of death or nonfatal myocardial infarction. Moreover, SRI increased the prognostic power of the model on top of clinical and exercise testing variables and provided significant discrimination of survival. In conclusion, the SRI may help refine the prognostic stratification of patients with a negative exercise test result using standard electrocardiographic criteria.

Simultaneous echocardiography and myocardial perfusion single photon emission computed tomography associated with dobutamine stress to predict long-term cardiac mortality in normotensive and hypertensive patients

BACKGROUND

Echocardiography and myocardial scintigraphy associated with dobutamine stress are used for assessing risk in coronary artery disease. We compared the accuracy of the two modalities applied simultaneously for predicting long-term cardiac mortality in normotensive and hypertensive patients.

METHODS

Three hundred and fifty-one consecutive patients underwent dobutamine stress with simultaneous echocardiography and Tc-sestamibi single photon emission computed tomography (SPECT). Fifty patients underwent early (<60 days) revascularization and were excluded; the analysis is based on 301 patients (131 hypertensives and 170 normotensives).

RESULTS

The prevalence of additional risk factors, heart failure, prior myocardial infarction and prior revascularization was similar in the two groups of patients. An abnormal stress echocardiogram was detected in 101 (59%) normotensives and 80 (61%) hypertensives (NS), while 113 (66%) normotensives and 83 (63%) hypertensives (NS) showed abnormal myocardial perfusion. The agreement was 81% (kappa = 0.59) in hypertensives and 82% (kappa = 0.62) in normotensives. During 7.3 +/- 2.8 years of follow-up, 17 (13%) hypertensives and 26 (15%) normotensives died from cardiac causes (P = 0.62). In normotensives, the annual mortality rate was 0.8 for normal echo and 1.3 for normal scan, 2.8 for abnormal echo and 2.6 for abnormal scan. In hypertensives, it was 0.5 for normal echo, 0% for normal scan, 2.6 for abnormal echo and 2.8 for abnormal scan. Each test was associated with higher survival in the case of negative compared to positive results in both normotensive and hypertensive patients (log-rank chi-square 16.4, P < 0.001).

CONCLUSIONS

Dobutamine stress echocardiography and SPECT are equally effective in predicting long-term cardiac death in both normotensive and hypertensive patients.

Stress Recovery Index for Risk Stratification of Asymptomatic Patients Following Coronary Bypass Surgery

OBJECTIVE

To prospectively assess the prognostic value of the stress recovery index (SRI) following coronary bypass surgery.

DESIGN AND PATIENTS

Two hundred seventy-eight patients who had undergone coronary bypass surgery and participated in a secondary prevention program were exercise tested and prospectively followed up for a median of 36 months. Cardiac death, nonfatal infarction, and need for further revascularization were target end points. SRI, defined as the difference in absolute values between the area of heart rate-adjusted ST-segment depression during exercise and recovery, was derived in all. Clinical data, resting ejection fraction, and exercise testing data of patients were entered into a sequential Cox model; SRI was entered last. Model validation was performed by bootstrap adjusted by the degree of optimism in estimates. Survival curves were set up using Kaplan-Meier method and compared by the log-rank test.

RESULTS

SRI was the only significant and independent prognostic indicator (hazard ratio, 0.68; 95% confidence interval, 0.53 to 0.89) and increased the prognostic power of the model on top of clinical and exercise testing variables, as demonstrated by the significant (p = 0.01) increase of the area under the receiver operating characteristic curve of the risk function. Survival analysis showed ascending SRI quartiles to identify a significant (p = 0.001) increase in event-free survival.

CONCLUSIONS

SRI is of value in predicting outcome after coronary bypass surgery and provides additional prognostic information over clinical and exercise testing data.