Improved risk stratification in unstable angina: identification of patients at low risk for in-hospital cardiac events by admission echocardiography

Prognostic value of unrecognised myocardial infarction detected by late gadolinium-enhanced MRI in diabetic patients with normal global and regional left ventricular systolic function

OBJECTIVES

To determine whether the detection of unrecognised myocardial infarction (MI) using late gadolinium-enhanced (LGE)-magnetic resonance imaging (MRI) can provide prognostic information in diabetic patients with normal ECG as well as normal global and regional left ventricular (LV) function.

METHODS

From 449 diabetic patients who had complete cine- and LGE-MRI, 321 patients with histories of CAD, ischaemic ECG changes and abnormal cine MRI findings (LV ejection fraction <50 % or presence of regional wall motion abnormality) were excluded. The presence and extent of LGE were determined in the remaining 128 patients. Follow-up information was obtained for the occurrence of major adverse cardiovascular events (MACE) defined as cardiac death, acute MI, heart failure, unstable angina and significant ventricular arrhythmias in 120 patients.

RESULTS

Of 120 patients, 18 (15 %) had LGE. During follow-up (median, 27 months), six patients with LGE (33.3 %) and four patients without LGE (3.9 %) experienced MACE, resulting in an annualised event rate of 7.7 % and 0.9 %, respectively (log-rank P <0.001). The presence of LGE was associated with an eight-fold increased hazard for MACE (HR, 8.84; P = 0.001).

CONCLUSIONS

LGE-MRI can detect unrecognised MI and may improve the risk stratification of diabetic patients with no CAD history, normal ECG and normal LV systolic function.

KEY POINTS

• Late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) can identify subtle myocardial abnormalities. • LGE-MRI can detect myocardial infarction missed by ECG and cine-MRI. • Unrecognised MI detected by LGE-MRI was associated with adverse cardiac events. • LGE-MRI helps clinicians to assess diabetic patients with unrecognised MI.

Regional left ventricular myocardial dysfunction as a predictor of incident cardiovascular events MESA (multi-ethnic study of atherosclerosis)

OBJECTIVES

We sought to examine the prognostic value of subclinical left ventricular (LV) regional myocardial dysfunction (RMD) measured by magnetic resonance imaging (MRI) among asymptomatic individuals.

BACKGROUND

LV RMD, defined as segmental impairment in systolic wall thickening, predicts adverse events in patients with established cardiovascular disease. MRI is highly accurate for detecting subtle RMD, of which the prognostic significance in a large multiethnic asymptomatic population is not known.

METHODS

We used MRI to evaluate baseline regional LV myocardial function and prospectively followed a multiethnic (African American, Caucasian, Chinese, and Hispanic) population-based sample of 4,510 men and women without cardiovascular disease for a mean of 4.6 years. Regional myocardial dysfunction was defined as the presence of impaired systolic wall thickening (<10th percentile of segment-specific population distribution) in ≥2 contiguous LV segments within any given coronary artery territory.

RESULTS

Baseline prevalence of RMD was 25.6%. Heart failure developed in 34 (1.0%) and 30 (2.6%) participants without and with RMD, respectively (p < 0.001). After adjustment for demographics and traditional risk factors, RMD remained independently associated with incident heart failure (hazard ratio [HR]: 2.62; 95% confidence interval [CI]: 1.56 to 4.39; p < 0.001). The relationship persisted after further adjustment for biomarkers of reported association with cardiovascular disease and indexes of global LV systolic dysfunction and hypertrophy (HR: 1.80; 95% CI: 1.02 to 3.20; p = 0.044). Similarly, RMD independently conferred an increased risk for hard coronary events (myocardial infarction or death from coronary heart disease; HR: 1.75; 95% CI: 1.06 to 2.89; p = 0.029), the composite of hard coronary events and stroke (HR: 1.72; 95% CI: 1.16 to 2.56; p = 0.005), and all atherosclerotic cardiovascular events (HR: 1.50; 95% CI: 1.09 to 2.07; p = 0.012).

CONCLUSIONS

Among an asymptomatic multiethnic American cohort, RMD is an independent predictor beyond traditional risk factors and global LV assessment for incident heart failure and atherosclerotic cardiovascular events. The clinical utility of early recognition of this subclinical phenotype deserves further investigation. (Multi-Ethnic Study of Atherosclerosis [MESA]; NCT00005487).

Randomized control trial investigating the influence of coffee on heart rate variability in patients with ST-segment elevation myocardial infarction

BACKGROUND

Cardiac autonomic dysfunction post ST-segment elevation myocardial infarction (STEMI) has been linked to an excess risk of premature cardiovascular morbidity and mortality above those with normal autonomic function post-STEMI.

AIM

The aim of this study was to evaluate the effect of acute ingestion of coffee on autonomic function and cardiovascular outcomes in patients with acute STEMI.

DESIGN

Randomized control trial.

METHODS

We randomized 103 patients with acute STEMI, admitted to our Coronary Care Unit, to receive regular coffee (caffeinated) or de-caffeinated coffee using a randomized controlled double-blinded design. Heart rate variability was assessed 5 days post-STEMI to assess the effect of caffeine on autonomic function.

RESULTS

In the group randomized to regular coffee, parasympathetic activity increased by up to 96% (P = 0.04) after 5 days. There was no detrimental effect of regular coffee on cardiac rhythm post-STEMI.

CONCLUSION

Coffee ingestion is associated with an increase in parasympathetic autonomic function immediately post-STEMI. Coffee was found to be safe and not associated with any adverse cardiovascular outcomes in the short term.

Prevalence and Prognostic Significance of Wall-Motion Abnormalities in Adults Without Clinically Recognized Cardiovascular Disease

Background— Left ventricular wall motion (WM) abnormalities have recognized prognostic significance in patients with coronary or other heart diseases; however, whether abnormal WM predicts adverse events in adults without overt cardiovascular disease has not been assessed. Our objective was to determine whether echocardiographic WM abnormalities predict subsequent cardiovascular events in a population-based sample.

Methods and Results— Participants (n=2864, mean age 60±8 years, 64% women) without clinically evident cardiovascular disease in the second Strong Heart Study examination who had complete echocardiographic WM assessment were studied. Echocardiographic assessment revealed that 5% of participants (n=140) had focal hypokinesia, and 1.5% (n=42) had WM abnormalities. Relationships between WM abnormalities and fatal and nonfatal cardiovascular events (including myocardial infarction, stroke, coronary artery disease, and heart failure; n=554) and cardiovascular death (n=182) during 8±2 years follow-up were examined. In Cox regression, after adjustment for age, gender, waist/hip ratio, systolic blood pressure, and diabetes mellitus, segmental WM abnormalities were associated with a 2.5-fold higher risk of cardiovascular events and a 2.6-fold higher risk of cardiovascular death (both P <0.0001). In similar multivariable models, global WM abnormalities were associated with a 2.4-fold higher risk of cardiovascular events ( P =0.001) and a 3.4-fold higher risk of cardiovascular death ( P =0.003).

Conclusions— Echocardiographic left ventricular WM abnormalities in adults without overt cardiovascular disease are associated with 2.4- to 3.4-fold higher risks of cardiovascular morbidity and mortality, independent of established risk factors.

Independent value of tissue harmonic echocardiography for risk stratification in patients with non-ST-segment elevation acute chest pain

BACKGROUND

Clinical factors, electrocardiography, and cardiac troponins provide a satisfactory, although not ideal, means for risk-stratifying patients with non-ST-segment elevation acute chest pain. Tissue harmonic echocardiography enables improved assessment of wall motion abnormalities compared with fundamental echocardiography and may be a useful adjunct for the detection of myocardial ischemia and infarction. We aimed to determine the value of tissue harmonic echocardiography in relation to electrocardiographic and biochemical factors for risk stratification of these patients.

RESULTS

Eighty patients with non-ST-segment elevation chest pain were studied using tissue harmonic echocardiography and troponin-T and -I. Fifty-five (69%) patients had abnormal electrocardiograms and 47 (59%) patients had abnormal echocardiograms. Thirteen patients (17%) had elevated troponin-T levels and 17 (21%) had elevated levels of troponin-I. Twelve patients (15%) had a myocardial infarction as the presenting event and, of the remaining 68 patients, 24 sustained an adverse cardiac event during the follow-up period (3 cardiac deaths, 4 nonfatal myocardial infarctions, 17 revascularization procedures). Troponin-T (98%), troponin-I (97%), and echocardiography (97%) all had similar negative predictive values for myocardial infarction as the presenting event, but troponin-T was the only independent predictor of this endpoint (relative risk 230, 95% CI 22-2427). An abnormal echocardiogram was the only independent predictor of subsequent events. The independent predictors of all events were age, troponin-T, and echocardiography.

CONCLUSION

Tissue harmonic echocardiography provides independent information for risk stratification of patients with non-ST-segment elevation acute chest pain.

A comparison trial for stratifying intermediate-risk chest pain: benefits of emergency department observation centers

Chest pain of uncertain etiology (intermediate-risk chest pain [IR-CP]) constitutes a majority of acute chest pain presentations to emergency departments (EDs). A before- and-after trial of 2197 IR-CP patients transferred from the hospital's ED to one of three units-ED-based observation center (ED-OC), inpatient observation center (IN-OC), and inpatient units-compared mean cost, length of stay, and safety over a 2-year period. The mean per patient cost for management of IR-CP was lower in the ED-OC ($1642) than the IN-OC ($1910) or the inpatient units ($2785). The mean length of stay was shorter in the ED-OC (0.75 days) than in the IN-OC (1.18 days) or the inpatient units (2.16 days). Return rates were lower in the ED-OC at 7 days (0%) and at 6 months (0.45%) than the IN-OC (0% and 1.22%) or the inpatient units (0.77% and 3.67%). Overall hospital costs for managing IR-CP dropped significantly (12.5%) after the ED-OC was opened. ED-OCs provide a safe and cost-effective alternative to admission of IR-CP patients.

Lessons learned from a community hospital chest pain center

The iterative lessons from our studies suggest that creation of a chest pain center alone will not change the practice of chest pain management by most physicians. In 1993 we established a chest pain center; in mid-1995 we established a patient management algorithm directing intermediate-risk patients to the chest pain center rather than admit them to the hospital. The creation of a chest pain center did not reduce the rate of chest pain admission by mid-1995. After the patient management algorithm was created, admittances dropped by a rate of 21% (p <0.001) and chest pain center usage increased by +1,726% (p <0.001). Among the 473 patients treated and discharged in the chest pain center after mid-1995, 333 (70%) were considered intermediate risk. No patient died after discharge from the chest pain center and there was 1 non-Q-wave myocardial infarction. We conclude that a chest pain management algorithm in a chest pain center can be safe, yet effective, for identifying high-risk patients for admission and low-risk patients for discharge.