Prognostic value of stress-gated Tc-99m sestamibi SPECT after acute myocardial infarction

Stress-gated technetium-99m (Tc-99 m) sestamibi single-photon emission computed tomography (SPECT) is used to risk stratify patients after acute myocardial infarction (AMI). In clinical practice, results of this test are used primarily to identify patients with myocardial ischemia for intervention. The value of this test to risk stratify patients with AMI not at high ischemic risk has not been addressed. More than 1-year follow-up was undertaken in 124 patients who underwent predischarge gated Tc-99m sestamibi SPECT studies and who did not undergo subsequent revascularization. Clinical variables and test-derived variables were evaluated to predict cardiac death, recurrent AMI, and hospitalization for unstable angina, congestive heart failure, or coronary revascularization. Independent predictors by multivariate analysis for cardiac death or recurrent AMI were a history of prior AMI (relative risk [RR] = 5.32, confidence interval [CI] 2.17 to 12.96), a low exercise capacity (RR = 6.84, CI 1.99 to 23.48), and left ventricular (LV) ejection fraction (EF) <40% (RR = 2.63, CI 1.04 to 6.38). The incidence of cardiac death or recurrent AMI was 29.8% in patients with a low exercise capacity versus 4.5% in those with good exercise capacity, and 38.1% in patients with LVEF <40% versus 9.4% in those with LVEF >40%. Independent predictors of cardiac death, AMI, or hospitalization for unstable angina, congestive heart failure, or revascularization were a history of prior AMI (RR = 2.24, CI 1.11 to 4.50) and LVEF <40% (RR = 3.13, CI 1.64 to 5.95). Among patients followed after AMI without revascularization Tc-99m sestamibi SPECT can identify a high-risk subset. The strongest independent predictors are poor exercise capacity and LVEF < 40%.     

Comparison of late outcome in patients with versus without angina pectoris having reversible perfusion abnormalities during dobutamine stress technetium-99m sestamibi single-photon emission computed tomography

The aim of this study was to assess the prognostic significance of reversible perfusion abnormalities in patients without angina during dobutamine stress technetium-99m sestamibi single-photon emission computed tomography (SPECT). The study comprised 224 patients (age 60 +/- 11 years, 144 men) with completely or partially reversible perfusion abnormalities during dobutamine stress sestamibi SPECT. Follow-up end points were hard cardiac events (cardiac death and nonfatal myocardial infarction). Angina occurred in 93 patients (42%) during the dobutamine stress test (symptomatic ischemia group). The 131 patients without dobutamine-induced angina represented the silent ischemia group. There was no significant difference between patients with and without angina with regard to summed stress perfusion score (5.3 +/- 2.5 vs 5.2 +/- 2.2, p = 0.9) or summed ischemic score (3.1 +/- 1.7 vs 3.2 +/- 1.4, p = 0.7). During a median follow-up of 7.2 years, cardiac death occurred in 14 patients (15%) with and in 21 patients (16%) without angina. Nonfatal myocardial infarction occurred in 8 patients (9%) with and in 13 patients (10%) without angina. In a multivariate analysis model of clinical and perfusion data, independent predictors of cardiac events were age (hazard ratio 1.02, confidence intervals [CI] 1.01 to 1.05 per year increment), diabetes mellitus (hazard ratio 1.9, CI 1.2 to 3.4), and ischemic perfusion score (hazard ratio 2.1, CI 1.3 to 3.8). Patients with silent ischemia defined as reversible perfusion abnormalities without associated angina during dobutamine stress sestamibi SPECT imaging had similar incidences of ischemia and similar cardiac event rates compared with patients with symptomatic ischemia. Therefore, the absence of angina in association with reversible perfusion abnormalities should not be interpreted as a sign of a more benign prognosis.     

Accuracy of imaging technologies in the diagnosis of acute cardiac ischemia in the emergency department: a meta-analysis

STUDY OBJECTIVE: We sought to quantitatively evaluate the evidence on the diagnostic performance of imaging technologies (including rest and stress echocardiography and technetium-99m sestamibi scanning) for the diagnosis of acute cardiac ischemia and acute myocardial infarction in the emergency department. METHODS: We conducted a systematic review and meta-analysis of the English-language literature published between 1966 and December 1998. Both prospective and retrospective studies qualified for the assessment of diagnostic performance. Diagnostic performance was assessed by means of random-effect estimates of test sensitivity, specificity, and the diagnostic odds ratio and was summarized by using summary receiver-operating characteristic curves. RESULTS: Diagnostic accuracy was evaluated in 10 studies of rest echocardiography, 2 studies of dobutamine stress echocardiography, and 6 studies of technetium-99m sestamibi scanning. However, only 3 rest echocardiography and 5 technetium-99m sestamibi studies evaluated patients strictly in the ED setting. Patient populations were often highly selected to represent low- or moderate-risk groups. When limited to ED studies, rest echocardiography showed excellent sensitivity of 93% (95% CI, 81% to 97%) and good specificity of 66% (95% CI, 43% to 83%). The results were similar when all studies were considered, including data from reports of admitted patients and patients sent to the cardiac care unit. There was insufficient literature on stress echocardiography in the ED to properly assess the technology. Technetium-99m sestamibi scanning also showed excellent sensitivity (range, 91.5% to 100%) and good specificity (range, 49.3% to 84.4%) for acute myocardial infarction; for acute cardiac ischemia, the random-effects pooled sensitivity was 89% (95% CI, 73% to 96%), and the pooled specificity was 77% (95% CI, 63% to 87%). CONCLUSION: For selected low- and moderate-risk patient groups, echocardiography and technetium-99m sestamibi imaging appear to have very good diagnostic performance with a similar sensitivity and specificity profile. More evidence should be accumulated on their performance specifically in the ED setting.     

Prognostic value of exercise stress technetium-99m-tetrofosmin myocardial perfusion imaging in patients with normal baseline electrocardiograms

Exercise stress electrocardiography is the recommended method for cardiac evaluation of patients with normal electrocardiograms (ECGs). There are no data to indicate an independent value of myocardial perfusion imaging (MPI) in predicting mortality in these patients. This study assessed the value of exercise stress MPI in predicting mortality in patients with normal baseline ECGs. We studied 319 patients (55 +/- 10 years of age; 180 men) with normal ECGs by exercise stress technetium-99m tetrofosmin MPI. End points during follow-up were cardiac and all-cause mortalities and hard cardiac events. A normal scan was detected in 190 patients (60%). Myocardial perfusion abnormalities were fixed in 59 patients (18%) and reversible in 70 (23%). During a mean follow-up of 7 +/- 1.2 years, 46 patients (14%) died. Death was considered cardiac in 28 patients (9%). Nonfatal myocardial infarction occurred in 12 patients (4%). Annual cardiac death rates were 0.4% in patients with normal perfusion, and 2.7% in patients with reversible defects. Annual total mortality rates were 1.1% in patients with normal perfusion and 3.4% in patients with reversible defects. In a multivariate analysis model, reversible perfusion abnormalities were associated with cardiac death (RR 2.8, 95% confidence interval 1.6 to 5.1) and hard cardiac events (RR 2.7, 95% confidence interval 1.5 to 4.5). Perfusion abnormalities in multivessel distribution were predictive of all-cause mortality (RR 2, 95% confidence interval 1.4 to 3.2). ST-segment depression was not significantly associated with events. In conclusion, stress technetium-99m tetrofosmin MPI provides independent information for predicting cardiac and overall mortalities in patients with normal ECGs. Reversible perfusion abnormalities, but not ischemic electrocardiographic changes, are predictive of outcome in these patients.     

Outcome With Calcium Channel Antagonists After Myocardial Infarction: A Community-Based Study

Objectives. We sought to estimate the risk of death and recurrent myocardial infarction associated with the use of calcium antagonists after myocardial infarction in a population-based cohort study.Background. Calcium antagonists are commonly prescribed after myocardial infarction, but their long-term effects are not well established.Methods. Patients 25 to 69 years old with a suspected myocardial infarction were identified and followed up through a community-based register of myocardial infarction and cardiac death (part of the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease [MONICA] Project in Newcastle, Australia). Data were collected by review of medical records, in-hospital interview and review of death certificates.Results. From 1989 to 1993, 3,982 patients with a nonfatal suspected myocardial infarction were enrolled in the study. At hospital discharge, 1,001 patients were treated with beta-adrenergic blocking agents, 923 with calcium antagonists, 711 with both beta-blockers and calcium antagonists and 1,346 with neither drug. Compared with patients given beta-blockers, patients given calcium antagonists were more likely to suffer myocardial infarction or cardiac death (adjusted relative risk [RR] 1.4, 95% confidence interval [CI] 1.0 to 1.9), cardiac death (RR 1.6, 95% CI 1.0 to 2.7) and death from all causes (RR 1.7, 95% CI 1.1 to 2.6). Compared with patients given neither beta-blockers nor calcium antagonists, patients given calcium antagonists were not at increased risk of myocardial infarction or cardiac death (RR 1.0, 95% CI 0.8 to 1.3), cardiac death (RR 0.9, 95% CI 0.6 to 1.2) or death from all causes (RR 1.0, 95% CI 0.7 to 1.3). No excess in risk of myocardial infarction or cardiac death was observed among patients taking verapamil (RR 0.9, 95% CI 0.6 to 1.6), diltiazem (RR 1.1, 95% CI 0.8 to 1.4) or nifedipine (RR 1.3, 95% CI 0.7 to 2.2) compared with patients taking neither calcium antagonists nor beta-blockers.Conclusions. These results are consistent with randomized trial data showing benefit from beta-blockers after myocardial infarction and no effect on the risk of recurrent myocardial infarction and death with the use of calcium antagonists. Comparisons between beta-blockers and calcium antagonists favor beta-blockers because of the beneficial effects of beta-blockers and not because of adverse effects of calcium antagonists.     

Postsystolic thickening detected by Doppler myocardial imaging: a marker of viability or ischemia in patients with myocardial infarction

BACKGROUND: Postsystolic thickening (PST) of ischemic myocardial segments has been reported to account for the characteristic heterogeneity or regional asynchrony of myocardial wall motion during acute ischemia. HYPOTHESIS: Postsystolic thickening detected by Doppler myocardial imaging (DMI) could be a useful clinical index of myocardial viability or peri-infarction viability in patients with myocardial infarction (MI). METHODS: Doppler myocardial imaging was recorded at each stage of a standard dobutamine stress echocardiogram (DSE) in 20 patients (16 male, 60 +/- 13 years) with an MI in the territory of the left anterior descending artery. Myocardial velocity data were measured in the interventricular septum and apical inferior segment of the MI territory. Postsystolic thickening was identified if the absolute velocity of PST was higher than peak systolic velocity in the presence of either a resting PST > 2.0 cm/s or if PST doubled at low-dose dobutamine infusion. RESULTS: Doppler myocardial imaging data could be analyzed in 38 ischemic segments (95%), and PST was observed in 21 segments (55%), including 3 segments showing PST only at low-dose dobutamine infusion. There was no significant difference of baseline wall motion score index (2.1 +/- 0.3 vs. 2.1 +/- 0.6, p = 0.77) or peak systolic velocity (1.1 +/- 1.1 vs. 1.9 +/- 2.0 cm/s, p = 0.05) between segments with and without PST. Peri-infarction ischemia or viability during DSE was more frequently observed in segments with PST than in those without (86 vs. 24%, p < 0.05). The sensitivity and specificity of PST for prediction of peri-infarction viability or ischemia was 82 and 81%, respectively. CONCLUSIONS: Postsystolic thickening in the infarct territory detected by DMI is closely related with peri-infarction ischemia or viability at DSE.     

氯吡格雷与阿司匹林抗血小板治疗ST段抬高型急性心肌梗死患者的系统评价

目的 系统评价氯吡格雷与阿司匹林双重抗血小板治疗ST段抬高型急性心肌梗死(acute myocardial infarction,ST-AMI)患者的有效性和安全性. 方法 应用计算机检索美国国立生物医学信息中心PubMed医学数据库、荷兰医学文摘embase数据库、Cochrane图书馆临床对照试验数据库(2007年第3期)和中国生物医学文献数据库(CBM)、中文科技期刊全文数据库(CNKI)、维普资讯网中文科技期刊数据库(VIP)、万方医学数据库,同时筛检纳入文献的参考文献.收集氯吡格雷联用阿司匹林治疗ST-AMI的随机和半随机对照试验,两名评价员独立评价文献质量和提取资料,并采用RevMan 4.2软件对资料进行Meta分析. 结果共纳入10个研究,52 433例患者.Meta分析结果显示:(1)与单用阿司匹林比较,氯吡格雷与阿司匹林双重抗血小板治疗能降低任何原因导致的死亡(RR=0.91,95% CI为0.85～0.97)、再发心肌梗死(RR=0.80,95%CI为0.72～0.89)、脑卒中(RR=0.81,95% CI为0.68～0.96)、心肌梗死后心绞痛(RR=0.35,95% CI为0.19～0.66)、冠状动脉内血栓(RR=0.73,95% CI为0.64～0.83)和降低死亡、再发心肌梗死或脑卒中的联合终点事件(RR=0.89,95% CI为0.84～0.95)的发生率;(2)改善心力衰竭和梗死相关动脉TIMI血流情况比较,差异无统计学意义(RR=0.97,95% CI为0.92～1.03;RR=1.14,95%CI为1.00～1.30;P＞0.05);(3)氯吡格雷与阿司匹林双重抗血小板治疗与单用阿司匹林比较,并发症出血相似(RR=1.1l,95% CI为0.92～1.34). 结论 与单用阿司匹林比较,联用氯吡格雷和阿司匹林能降低ST-AMI患者的死亡(任何原因)、再发心肌梗死、脑卒中及梗死后心绞痛、冠状动脉内血栓和降低死亡、再发心肌梗死或脑卒中的联合终点事件的发生率,但在改善心力衰竭和梗死相关动脉TIMI血流方面两者疗效相当.短期氯吡格雷和阿司匹林双重抗血小板治疗与单用阿司匹林发生出血并发症相似.     

Association of myocardial ischemia with mortality and implantable cardioverter-defibrillator therapy in patients with coronary artery disease at risk of arrhythmic death.

OBJECTIVES: We sought to assess the relation between myocardial ischemia during stress echocardiography and major events in patients with implantable cardioverter-defibrillator (ICD). BACKGROUND: The association of myocardial ischemia with subsequent ICD therapy and mortality is unknown. METHODS: We studied 90 patients (age 65 +/- 13 years, 27 women) with history of coronary heart disease who received ICD for primary (53 patients) or secondary (37 patients) prevention of sudden cardiac death. Sixty-five (72%) patients had a previous coronary artery bypass surgery. Patients underwent exercise treadmill or dobutamine stress echocardiography. Ischemia was defined as new or worsening wall motion abnormalities. End points were death and appropriate ICD therapy. RESULTS: Mean ejection fraction was 34 +/- 12%. During a mean follow-up of 2.8 +/- 1.5 years, 5 patients died and 19 patients had ICD therapy. Ischemia was detected in 20 of 24 patients with subsequent events and in 24 of 66 patients without (83% vs. 36%, p < 0.001). Events occurred in 17 of the 32 patients (53%) with both ischemia and inducible ventricular tachycardia (VT) on electrophysiologic (EP) studies. None of the 16 patients without ischemia or inducible VT on EP studies had events. In a Cox multivariate analysis model, independent predictors of events were a history of spontaneous sustained VT (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.3 to 3.8), inducible VT on EP studies (HR 1.7, 95% CI 1.2 to 4.5), and ischemia (HR 2.1, 95% CI 1.2 to 3.5). CONCLUSIONS: Ischemia during stress echocardiography is an independent predictor of death and ICD therapy in patients with coronary heart disease at high risk of arrhythmic death. Patients without inducible ischemia or VT on a previous EP study have a very low risk of events. A combination of ischemia and a positive EP study is associated with a very high risk of events.     

Reperfusion therapy in elderly patients with acute myocardial infarction: a randomized comparison of primary angioplasty and thrombolytic therapy

OBJECTIVES: This study sought to determine the short- and long-term outcome of primary coronary angioplasty and thrombolytic therapy for acute myocardial infarction (AMI) in patients older than 75 years of age. BACKGROUND: The benefit of reperfusion therapy in elderly patients with AMI is uncertain, although elderly people account for a large proportion of deaths. METHODS: We randomly assigned a total of 87 patients with an AMI who were older than 75 years to treatment with angioplasty or intravenous (IV) streptokinase. Clinical outcome was measured by taking the end points of death and the combination of death, reinfarction or stroke during follow-up. RESULTS: The primary end point, a composite of death, reinfarction or stroke, at 30 days had occurred in 4 (9%) patients in the angioplasty group as compared with 12 (29%) in the thrombolysis group (p = 0.01, relative risk [RR]: 4.3, 95% confidence interval [CI]: 1.2 to 20.0). At one year the corresponding figures were 6 (13%) and 18 (44%), respectively (p = 0.001, RR: 5.2, 95% CI: 1.7 to 18.1). CONCLUSIONS: In this series of patients with AMI who were older than 75 years, primary coronary angioplasty had a significant clinical benefit when compared with IV streptokinase therapy.     

Usefulness of technetium-99m sestamibi myocardial perfusion SPECT in detection of cardiovascular involvement in patients with systemic lupus erythematosus or systemic sclerosis

The main purpose of the study was to evaluate the utility of technetium-99m sestamibi myocardial perfusion single-photon emission computed tomography (Tc-99m sestamibi SPECT) in detection of cardiac involvement in systemic lupus erythematosus (SLE) or systemic sclerosis (SS) patients. Fifty SLE or SS female patients with cardiac symptom/sign such as chest discomfort and/or dyspnea and/or occasionally palpitation and 50 SLE or SS female patients without any cardiac symptom/sign were investigated using Tc-99m sestamibi SPECT during rest and stress after dipyridamole infusion. Twenty-five age- and sex-matched healthy females were also included as controls in this study. The results of Tc-99m sestamibi SPECT were classified into four types including normal, persistent perfusion defect (PD), reversible perfusion defect (RD), and reverse perfusion defect (RR). The results of Tc-99m sestamibi SPECT in the 25 healthy females were normal. Perfusion abnormalities were detected in 44/50 (88%) symptomatic SLE or SS patients. However, myocardial perfusion abnormalities were only detected in 19/50 (38%) asymptomatic SLE or SS patients (P value<0.05 by a chi2 test). However, for risk factor of coronary artery disease and abnormal resting EKG, the incidences were not significant between symptomatic and asymptomatic patients (P values >0.05 by a chi2 test). Tc-99m sestamibi SPECT is a useful noninvasive imaging modality to detect cardiac involvement in symptomatic or asymptomatic SLE or SS patients.     

Prognostic value of pharmacologic stress echocardiography in patients with left bundle branch block

PURPOSE: Although coronary artery disease is a frequent cause of left bundle branch block, the prognostic value of myocardial ischemia in patients with this conduction abnormality has not been defined. We investigated the value of pharmacologic stress echocardiography in risk stratification of patients with left bundle branch block. PATIENTS AND METHODS: Three hundred eighty-seven patients [230 men and 157 women, mean (+/- SD) age, 64 +/- 9 years] with complete left bundle branch block on the resting electrocardiogram underwent dobutamine (n = 217) or dipyridamole (n = 170) stress echocardiography to evaluate suspected or known coronary artery disease. A summary wall motion score (on a one to four scale) was calculated. The primary end points were cardiac death and nonfatal myocardial infarction. RESULTS: A positive echocardiographic result (evidence of ischemia) was detected in 109 (28%) patients. During a mean follow-up of 29 +/- 26 months, there were 21 cardiac deaths and 20 myocardial infarctions, 63 patients underwent coronary revascularization, and 1 patient received a heart transplant. In a multivariate analysis, four clinical and echocardiographic variables were associated with increased risk of cardiac death: resting wall motion score index [hazard ratio (HR) = 7.5 per unit; 95% confidence interval (CI), 2.8 to 20; P = 0.001], previous myocardial infarction (HR = 2.9; 95% CI, 1.1 to 7.3; P = 0.02), diabetes (HR = 2.7; 95% CI, 1.1 to 6.6; P = 0.03), and the change in wall motion score index from rest to peak stress (HR = 3.0 per unit; 95% CI, 1.0 to 8.6; P = 0.04). The 5-year survival was 77% in the ischemic group and 92% in the nonischemic group (P = 0.02). Four variables were associated with increased risk of cardiac death or infarction: previous myocardial infarction (HR = 3.4; 95% CI, 1.7 to 6.8; P = 0.0005), diabetes (HR = 2.4; 95% CI, 1.2 to 4.6; P = 0.01), resting wall motion score index (HR = 2.2 per unit; 95% CI, 1.1 to 4.1; P = 0.02), and positive echocardiographic result (HR = 2.2; 95% CI, 1.1 to 4.5; P = 0.03). The 5-year infarction-free survival was 60% in the ischemic group and 87% in the nonischemic group (P < 0.0001). Stress echocardiography significantly improved risk stratification in patients without previous myocardial infarction (P = 0.0001), but not in those with previous myocardial infarction (P = 0.08). In particular, it provided additional value over clinical and resting echocardiographic findings in predicting cardiac events among patients without previous infarction. CONCLUSIONS: Myocardial ischemia during pharmacologic stress echocardiography is a strong prognostic predictor in patients with left bundle branch block, particularly in those without previous myocardial infarction.     

Rescue angioplasty or repeat fibrinolysis after failed fibrinolytic therapy for ST-segment myocardial infarction: a meta-analysis of randomized trials.

OBJECTIVES: We sought to best estimate the benefits and risks associated with rescue percutaneous coronary intervention (PCI) and repeat fibrinolytic therapy as compared with conservative management in patients with failed fibrinolytic therapy for ST-segment myocardial infarction (STEMI). BACKGROUND: Fibrinolytic therapy is the most common treatment for STEMI; however, the best therapy in patients who fail to achieve reperfusion after fibrinolytic therapy remains uncertain. METHODS: We performed a meta-analysis of randomized trials using a fixed-effects model. We included 8 trials enrolling 1,177 patients with follow-up duration ranging from hospital discharge to 6 months. RESULTS: Rescue PCI was associated with no significant reduction in all-cause mortality (relative risk [RR] 0.69; 95% confidence interval [CI] 0.46 to 1.05), but was associated with significant risk reductions in heart failure (RR 0.73; 95% CI 0.54 to 1.00) and reinfarction (RR 0.58; 95% CI 0.35 to 0.97) when compared with conservative treatment. Rescue PCI was associated with an increased risk of stroke (RR 4.98; 95% CI 1.10 to 22.5) and minor bleeding (RR 4.58; 95% CI 2.46 to 8.55). Repeat fibrinolytic therapy was not associated with significant improvements in all-cause mortality (RR 0.68; 95% CI 0.41 to 1.14) or reinfarction (RR 1.79; 95% CI 0.92 to 3.48), but was associated with an increased risk for minor bleeding (RR 1.84; 95% CI 1.06 to 3.18). CONCLUSIONS: Rescue PCI is associated with improved clinical outcomes for STEMI patients after failed fibrinolytic therapy, but these benefits must be interpreted in the context of potential risks. On the other hand, repeat fibrinolytic therapy is not associated with significant clinical improvement and may be associated with increased harm.     

The prevalence and prognosis of unrecognized myocardial infarction and silent myocardial ischemia in patients undergoing major vascular surgery

OBJECTIVE: The aim of this study is to determine the prevalence and prognosis of unrecognized myocardial infarction (MI) and silent myocardial ischemia in vascular surgery patients. METHODS: In a cohort of 1092 patients undergoing preoperative dobutamine stress echocardiography and noncardiac vascular surgery, unrecognized MI was determined by rest wall motion abnormalities in the absence of a history of MI. Silent myocardial ischemia was determined by stress-induced wall motion abnormalities in the absence of angina pectoris. Beta blockers and statins were noted at baseline. During follow-up (mean: 6+/-4 years), all-cause mortality and major cardiac events (cardiac death or nonfatal MI) were noted. RESULTS: The prevalence of unrecognized MI and silent myocardial ischemia was 23 and 28%, respectively. Both diabetes and heart failure were important predictors of unrecognized MI and silent myocardial ischemia. During follow-up, all-cause mortality occurred in 45% and major cardiac events in 23% of patients. In multivariate analysis, unrecognized MI and silent myocardial ischemia were significantly associated with increased risk of mortality [hazard ratio (HR), 1.86; 95% confidence interval (CI), 1.53-2.25 and HR, 1.74; 95% CI, 1.46-2.06, respectively] and major cardiac events (HR, 2.15; 95% CI, 1.59-2.92 and HR, 1.86; 95% CI, 1.43-2.41, respectively). In patients with unrecognized MI, beta-blockers and statins were significantly associated with improved survival. Statins improved survival in patients with silent myocardial ischemia. CONCLUSIONS: In patients undergoing major vascular surgery, unrecognized MI and silent myocardial ischemia are highly prevalent (23 and 28%) and associated with increased long-term mortality and major cardiac events.     

Prognostic value of treadmill exercise echocardiography

INTRODUCTION AND OBJECTIVES: Exercise echocardiography (EE) is useful for diagnosing coronary disease, but little is known about its value for risk stratification. We aimed to determine: a) whether data from EE supplemented clinical data and data from exercise testing and resting echocardiography in predicting cardiac events; and b)whether the number and location of abnormal regions and their responses to exercise influenced risk stratification. PATIENTS AND METHOD: The 2,436 patients referred for EE were followed up for 2.1+/-1.5 years. Some 120 serious cardiovascular events (i.e., non-fatal myocardial infarction or cardiovascular death) occurred before revascularization. RESULTS: In 1203 patients (49%), EE gave abnormal results. There were 89 events in patients with an abnormal result (7.3%) and 31 in those with a normal result (2.5%; P<.0001). Multivariate analysis of clinical data, and data from exercise testing, resting echocardiography, and EE showed that male sex (RR=1.7; 95% CI, 1.1-2.8; P=.02), metabolic equivalents or METs (RR=0.9; 95% CI, 0.86-0.98; P=.01), peak heart rate x blood pressure (RR= 0.9;95% CI, 0.9; P=.002), resting wall motion score index (RR=2.5; 95% CI, 1.5-4.1; P<.0001), and number of abnormal regions at peak exercise (RR=1.4; 95% CI, 1.2-1.7; P<.0001) were independently associated with the risk of a serious event (final model chi2, 170; incremental P<.0001). The same variables, excluding sex, were independently associated with cardiovascular death (final model chi2, 169; incremental P=.01). CONCLUSIONS: Exercise echocardiography supplements clinical data and data from exercise testing and resting echocardiography in patients with known or suspected coronary artery disease.     

Alpha-2 adrenergic agonists to prevent perioperative cardiovascular complications: a meta-analysis

PURPOSE: To investigate the effects of alpha(2)-adrenergic agonists on perioperative mortality and cardiovascular complications in adults undergoing surgery. METHODS: MEDLINE (1966 to May 2002), EMBASE (1980 to May 2002), the Cochrane Clinical Trials Register, the Science Citation Index, and bibliographies of included articles were searched without language restriction. Randomized trials comparing preoperative, intraoperative, or postoperative (first 48 hours) administration of clonidine, dexmedetomidine, or mivazerol with controls were included. Studies had to report any of the following outcomes: mortality, myocardial infarction, ischemia, or supraventricular tachyarrhythmia. Treatment effects were calculated using the fixed-effects model. Heterogeneity was assessed using the Q test. RESULTS: Twenty-three trials comprising 3395 patients were included. Overall, alpha(2)-adrenergic agonists reduced mortality (relative risk [RR] = 0.64; 95% confidence interval [CI]: 0.42 to 0.99; P = 0.05) and ischemia (RR = 0.76; 95% CI: 0.63 to 0.91; P = 0.003) significantly. They also reduced mortality (RR = 0.47; 95% CI: 0.25 to 0.90; P = 0.02) and myocardial infarction (RR = 0.66; 95% CI: 0.46 to 0.94; P = 0.02) during vascular surgery. During cardiac surgery, alpha(2)-adrenergic agonists reduced ischemia (RR = 0.71; 95% CI: 0.54 to 0.92; P = 0.01) and were associated with trends toward lower mortality (RR = 0.49; 95% CI: 0.12 to 1.98; P = 0.3) and a reduced risk of myocardial infarction (RR = 0.83; 95% CI: 0.35 to 1.96; P = 0.7). CONCLUSION: Alpha-2 adrenergic agonists reduce mortality and myocardial infarction following vascular surgery. During cardiac surgery, they reduce ischemia and may also have effects on mortality and myocardial infarction. Large randomized trials are needed to evaluate these agents during cardiac and vascular surgery.     

Technetium-99m sestamibi myocardial perfusion imaging in the emergency room evaluation of chest pain

Objectives. The purpose of this investigation was to evaluate the practicality and short-term predictive value of acute myocardial perfusion imaging with technetium-99m sestamibi in emergency room patients with typical angina and a normal or nondiagnostic electrocardiogram (ECG).Background. Accuracy of emergency room chest pain assessment may be improved when clinical and ECG variables are used in conjunction with acute thallium-201 myocardial perfusion imaging. Technetium-99m sestamibi is a new radioisotope that is taken up by the myocardium in proportion to blood flow, but unlike thallium-201, it redistributes minimally after Injection. Technetium-99m sestamibi can thus be injected during chest pain, and images acquired 1 to 2 h later (when patients have been clinically stabilized) will confirm whether abnormalities of perfusion were present at the time of injection.Methods. One hundred two emergency room patients with typical angina (on the basis of a standardized angina questionnaire) and a normal or nondiagnostic ECG had a technetium-99m sestamibi injection during symptoms and were followed up for occurrence of adverse cardiac events (cardiac death, nonfatal myocardial infarction, coronary angioplasty, coronary surgery or coronary thrombolysis).Results. Univariate predictors of cardiac events included the presence of three or more coronary risk factors (p = 0.009, risk ratio 3.3) and an abnormal or equivocal acute technetium-99m sestamibi scan (p = 0.0001, risk ratio 13.9). Multivariate regression analysis identified an abnormal perfusion image as the only independent predictor of adverse cardiac events (p = 0.009). Of 70 patients with a normal perfusion scan, only 1 had a cardiac event compared with 15 patients with equivocal scans or 17 patients with abnormal scans, with a cardiac event rate of 13% and 71%, respectively (p = 0.0004).Conclusions. Initial myocardial perfusion imaging with technetium-99m sestamibi when applied in emergency room patients with typical angina and a normal or nondiagnostic ECG appears to be highly accurate to distinguishing between low and high risk subjects.     

Baseline clinical and angiographic variables associated with long-term outcome after successful intracoronary stent implantation.

Although randomized studies have demonstrated improved outcomes with stents over balloon angioplasty in straightforward coronary narrowings in low-risk patients, this advantage is less clear for complex lesions and high-risk patients. This study was designed to identify clinical and angiographic variables that are associated with long-term outcome after stent implantation. We identified 1,709 patients undergoing successful stent placement without in-hospital major adverse events. We analyzed clinical, lesional, and procedural variables to determine their correlation with outcome. Mean duration of follow-up was 1.6 +/- 1.4 years. Cox proportional-hazards models and stepwise methods were used to assess which covariates were potentially related to each end point. The occurrence of death/myocardial infarction (MI) was associated with any history of congestive heart failure (relative risk [RR] 3.3, 95% confidence interval [CI] 2.3 to 4.7, p <0.0001), procedure within 24 hours of MI (RR 2.3, CI 1.3 to 4.1, p = 0.0048), vein graft intervention (RR 1.8, CI 1.3 to 2.6, p = 0.0007), and prior MI (RR 1.8, CI 1.2 to 2.6, p = 0.004). Repeat revascularization was associated with multivessel stent placement (RR 1.8, CI 1.2 to 2.8, p = 0.006) and stent for abrupt closure (RR 1.7, CF 1.1 to 2.7, p = 0.03), but was less frequent with de novo lesions and right coronary artery lesions (RR 0.6, CI 0.5 to 0.8, p = 0.0007, and RR 0.8, CI 0.6 to 1.0, p = 0.05, respectively). The cumulative end point of death/MI/repeat revascularization was associated with congestive heart failure (RR 1.7, CI 1.3 to 2.2, p <0.0001), multivessel stent placement (RR 1.6, Cl 1.1 to 2.3, p = 0.03), warfarin therapy (RR 1.4, CI 1.2 to 1.8, p = 0.001), and procedure within 24 hours of MI (RR 1.5, CI 1.1 to 2.1, p = 0.02), but was less frequent with complete revascularization and right coronary artery intervention (RR 0.8, CI 0.7 to 0.99, p = 0.04, and RR 0.7, CI 0.6 to 0.9, p = 0.009, respectively). Thus, this study demonstrates that there are readily identifiable characteristics in patients treated successfully with stents that are associated with long-term outcome.     

Inflammatory cytokines provide limited early prognostic information in emergency department patients with suspected myocardial ischemia

STUDY OBJECTIVE: The aim of this study was to assess the early prognostic value of the inflammatory cytokines interleukin 6, interleukin 8, and tumor necrosis factor alpha in a cohort of emergency department (ED) patients with chest pain who have suspected myocardial ischemia. METHODS: One hundred eighteen patients with chest pain presenting to 2 urban EDs were studied. Interleukin 6, interleukin 8, and tumor necrosis factor alpha levels were assayed at presentation. The end point was the occurrence of a serious cardiac event (death, nonfatal acute myocardial infarction, myocardial revascularization, or readmission with an acute coronary syndrome) during the index admission or subsequent 3 months. RESULTS: Mean levels of all 3 cytokines were higher among patients experiencing a serious cardiac event, with the greatest differences observed in levels of interleukin 6 (mean 2.5 pg/mL [95% confidence interval (CI) 1.2 to 3.7 pg/mL] versus mean 9.8 pg/mL [95% CI 2.4 to 17.2 pg/mL]). Interleukin 6 had a sensitivity of 35% (95% CI 20% to 54%), a specificity of 86% (95% CI 76% to 92%), and an overall prognostic accuracy of 71% (95% CI 63% to 79%) for predicting serious cardiac events. However, logistic regression analysis revealed that the only independent predictor of an adverse outcome was an ECG suggestive of ischemia at presentation. CONCLUSION: Among patients presenting to the ED with suspected myocardial ischemia, higher levels of inflammatory cytokines are associated with an increased risk of a serious cardiac event during the subsequent 3 months. There is, however, considerable overlap in levels among patients who do and do not have a serious cardiac event, limiting their utility as predictors of outcome in individual patients.     

Prognostic importance of predischarge exercise capacity for long-term mortality and non-fatal myocardial infarction in patients admitted for suspected acute myocardial infarction and treated with metoprolol.

To evaluate the influence of acute beta-blockade on the ability of predischarge exercise test data to predict long-term prognosis in patients admitted for suspected acute myocardial infarction, patients randomized at hospital admission to intravenous metoprolol or placebo were studied. Among 190 patients discharged alive, total 4-year mortality was 20.5% (n = 39); (33 cardiac deaths, 6 non-cardiac deaths). Non-fatal infarction rate was 6.8% (n = 13). Multiple logistic regression analysis revealed that total mortality and non-fatal infarctions were independently predicted by (a) inability to perform predischarge stress testing (event-free survival for patients exercise tested 79.5% vs 56.9% for patients not eligible for testing; relative risk (RR) 1.40, 95% confidence interval (CI) 1.10-1.78; P = 0.01), and (b) low predischarge exercise capacity (RR 1.44, CI 1.08-1.93; P = 0.034). ST segment shift > or = 1 mm did not predict mortality or reinfarction. Administration of metoprolol in the acute phase did not influence the predictive value of these parametres. It is concluded that assessment of exercise capacity at early exercise testing yields independent information for later death and myocardial infarctions, and that beta-blockade with metoprolol does not influence the predictive value of early exercise testing.     

Prediction of cardiac death in hypertensive patients with suspected or known coronary artery disease by stress technetium-99m tetrofosmin myocardial perfusion imaging

BACKGROUND: There are currently insufficient data to indicate a role for stress myocardial perfusion imaging as a prognostic tool in hypertensive patients. OBJECTIVES: To assess the incremental value of stress myocardial perfusion imaging for the prediction of cardiac death in hypertensive patients relative to clinical data. PATIENTS: We studied 601 hypertensive patients (aged 59 +/- 10 years, 387 men) who underwent exercise bicycle or dobutamine (up to 40 microg/kg per min) stress technetium-99m tetrofosmin single photon emission computed tomography (SPECT) for evaluation of coronary artery disease. OUTCOME: Cardiac death during follow-up. RESULTS; An abnormal scan (reversible or fixed perfusion abnormalities) was detected in 293 (49%) patients (134 had reversible abnormalities). During a mean follow-up period of 3.1 +/- 1.3 years, 109 (18%) patients died; of whom, 42 patients (39%) died due to cardiac causes. Independent predictors of cardiac death were age [hazard ratio = 1.04, 95% confidence interval (CI) 1.01-1.08], history of previous myocardial infarction (hazard ratio = 2, CI 1.1-3.7), stress rate-pressure product (hazard ratio = 0.94, CI 0.87-0.98) and abnormal scan (hazard ratio = 4.7 CI 1.9-11.4). Both reversible and fixed abnormalities were predictive of death. The annual cardiac death rate was 5.3% in patients with an abnormal and 0.5% in patients with a normal perfusion scan. CONCLUSION: Stress technetium-99m tetrofosmin myocardial perfusion imaging provides prognostic information incremental to clinical data for the prediction of cardiac death in hypertensive patients with known or suspected coronary artery disease.