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Michael S Lauer

Publications and source records attributed to Michael S Lauer.

At least 37 records · Page 2Linked to original sources
PubMed2005

Cardiac rehabilitation and secondary prevention of coronary heart disease: an American Heart Association scientific statement from the Council on Clinical Cardiology (Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention) and the Council on Nutrition, Physical Activity, and Metabolism (Subcommittee on Physical Activity), in collaboration with the American association of Cardiovascular and Pulmonary Rehabilitation.

This article updates the 1994 American Heart Association scientific statement on cardiac rehabilitation. It provides a review of recommended components for an effective cardiac rehabilitation/secondary prevention program, alternative ways to deliver these services, recommended future research directions, and the rationale for each component of the rehabilitation/secondary prevention program, with emphasis on the exercise training component.

Coronary Disease↗
PubMed2005

In search of fewer independent risk factors.

More than 1100 articles now appear annually investigating "independent risk factors" or "independent predictors" for various clinical outcomes. In medical research, independence is generally defined in a statistical sense: a variable is called an independent risk factor if it has a significant contribution to an outcome in a statistical model that includes established risk factors. As such, independence is based on a specific statistical model and depends on the set of established risk factors included in that model. Even when strong statistical evidence indicates that a variable is an independent risk factor for an outcome, this does not necessarily indicate that the risk factor causally contributes to the outcome. The opposite is also true: risk factors that have causal relationships with the outcome will not necessarily prove to be independent risk factors. These are basic statistical principles that are too often given short shrift in medical research. Herein, we discuss the clinical implications conferred by the above definition of independence, primarily using examples from recent cardiovascular literature. A glossary and schema are provided to help clinicians and researchers understand and discuss these matters effectively.

Age Factors↗
PubMed2005

Prediction of death or myocardial infarction by exercise single photon emission computed tomography perfusion scintigraphy in patients who have had recent coronary artery stenting.

BACKGROUND: Although practice guidelines do not recommend routine exercise testing of patients after coronary stenting, several small studies have suggested that stress myocardial perfusion imaging can provide prognostic information about future adverse cardiac events. We sought to determine if exercise nuclear testing provides independent prognostic information in patients after coronary stenting. METHODS: We analyzed the outcomes of 370 patients who underwent dual isotope exercise nuclear scintigraphy at least 1 month after coronary stenting and had testing between April 1996 and May 2002. Patients were classified according to presence or absence of any ischemia. The primary endpoint was all-cause mortality or myocardial infarction (MI) during a median of 30 months (range 6-59) of follow-up. RESULTS: There were 86 patients (23%) who had ischemia. Major events--death or MI--occurred in 62 patients including 22 deaths. Among patients with no ischemia, the 30-month event rate was 9.1%, whereas among patients with ischemia, the event rate was 17.0% (P = .001). After adjusting for age, sex, standard cardiac risk factors, cardiac history, left ventricular ejection fraction, angiographic findings, procedural variables, exercise capacity, and heart-rate dynamics, the presence of scintigraphic evidence of ischemia predicted death or MI (adjusted hazard ratio 2.08, 95% CI 1.21-3.56, P = .008). The presence of ischemia similarly predicted events in asymptomatic patients (adjusted hazard ratio 2.19, 95% CI 1.17-4.11, P = .015). CONCLUSIONS: In patients with recent coronary stent placement, reversible nuclear perfusion defects independently predicted risk of death or MI.

Angioplasty, Balloon, Coronary↗
PubMed2005

Can we reliably predict long-term mortality after exercise testing? An external validation.

OBJECTIVE: The aim of the study was to derive and externally validate a mortality prediction rule for patients undergoing exercise testing. BACKGROUND: The prognostic value of exercise testing is increasingly appreciated. However, global prognosis estimates ideally should account for numerous routinely obtained variables, including demographics, risk factors, resting electrocardiogram, and multiple exercise test measures. METHODS: A prediction rule was derived by parametric hazards modeling on a derivation set of 46047 Cleveland Clinic patients (age 55 +/- 11 years, 67% male) who had no history of heart failure, valve disease, or atrial fibrillation. Twenty-two variables covering demographics, risk factors, exercise hemodynamics, and electrocardiogram findings at rest and during exercise were considered. The resulting model included 16 variables and was tested on 4981 patients (age 50 +/- 12 years, 55% male) who underwent exercise testing at West Virginia University. RESULTS: In the derivation cohort there were 3173 deaths during a mean of 7 years of follow-up, whereas in the validation cohort there were 180 deaths during a mean of 5 years of follow-up. Comparisons of predicted and observed death rates showed very good agreement among all patients across all spectrums of risk, as well as among prespecified high-risk subgroups. Model discrimination was also good, with c statistic of c = 0.79 in the derivation group and c = 0.81 in the validation cohort. CONCLUSIONS: We have externally validated a mortality prediction rule for patients undergoing exercise testing and confirmed its accuracy among a wide spectrum of patients.

Adult↗
PubMed2005

Aortic valve replacement in patients with mild or moderate aortic stenosis and coronary bypass surgery.

PURPOSE: To assess whether there is survival benefit for patients with mild or moderate aortic stenosis if they undergo aortic valve replacement at the time of coronary artery bypass surgery. METHODS: From 1985 to 1995 we evaluated all patients at our institution who underwent coronary artery bypass surgery and who had the echocardiographic diagnosis of mild (mean gradient <0 mm Hg and/or valve area >1.5 cm(2)) or moderate (mean gradient > or =30 and < or =40 mm Hg and/or valve area >1.0 < or =1.5 cm(2)) aortic stenosis. Using propensity analysis, survival was compared between 129 patients who underwent coronary artery bypass surgery alone and 78 patients who underwent concomitant coronary artery bypass surgery and aortic valve replacement. RESULTS: Perioperative mortality was similar among patients who underwent coronary artery bypass surgery alone compared with patients who underwent concomitant coronary artery bypass surgery and aortic valve replacement. By Kaplan-Meier analysis, 1-year and 8-year survival were better at 90% and 55% for patients who underwent concomitant coronary artery bypass surgery and aortic valve replacement compared with 85% and 39% for patients who underwent coronary artery bypass surgery alone (P <0.001). This benefit was limited to patients with moderate aortic stenosis (propensity-adjusted relative risk = 0.43; 95% confidence interval: 0.20 to 0.96; P = 0.04). CONCLUSION: Concomitant aortic valve replacement at the time of coronary artery bypass surgery for mild or moderate aortic stenosis appears to convey a survival advantage for patients with moderate aortic stenosis but not for those with mild aortic stenosis.

Aged↗
PubMed2004

Heart rate recovery and impact of myocardial revascularization on long-term mortality.

BACKGROUND: Although heart rate recovery (HRR) predicts mortality after exercise testing, its ability to identify patients likely to benefit after revascularization is unknown. We sought to determine whether HRR can identify patients likely to have improved survival after revascularization. METHODS AND RESULTS: A total of 8861 patients undergoing treadmill nuclear or echocardiographic testing were divided into early revascularization (percutaneous coronary intervention or bypass surgery within 3 months) and non-early revascularization groups. Prespecified subgroup analysis was performed based on the presence or absence of ischemia, normal or impaired functional capacity, and normal or abnormal HRR. The primary end point was all-cause mortality. Early revascularization occurred in 552 patients. We propensity-matched 508 early revascularization patients to 508 non-early revascularization patients on the basis of 48 possible confounders. This constituted the present study cohort. During 8-year follow-up, 232 patients died. Overall, revascularization was associated with a slight but not significant decrease in mortality (hazard ratio [HR] 0.80, 95% CI 0.62 to 1.03). A significant decrease in mortality after revascularization was present in patients with imaging evidence of stress-induced ischemia (HR 0.62, 95% CI 0.44 to 0.87). Ischemic patients with normal HRR had significantly lower mortality with revascularization (HR 0.55, 95% CI 0.34 to 0.90), whereas ischemic patients with abnormal HRR did not (HR 0.78, 95% CI 0.47 to 1.29); however, the test for interaction between these 2 groups was not significant (P=0.34). CONCLUSIONS: In patients with imaging evidence of myocardial ischemia, an abnormal HRR is associated with a nonsignificant trend toward blunting the survival improvement associated with early revascularization. HRR does not appear to identify patients likely to have a survival benefit.

Aged↗
PubMed2004

ST-segment resolution 60 minutes after combination treatment of abciximab with reteplase or reteplase alone for acute myocardial infarction (30-day mortality results from the resolution of ST-segment after reperfusion therapy substudy).

The combination of abciximab with thrombolytic therapy when treating acute ST-elevation myocardial infarction has been hypothesized to enhance microvascular perfusion. Resolution of ST-segment elevation after thrombolytic therapy is believed to be a marker of myocardial reperfusion and to predict mortality rate. Among 16,588 patients enrolled in the Fifth Global Use of Strategies to Open Occluded Arteries in Acute Myocardial Infarction trial, 1,764 consecutive patients from selected centers had their study electrocardiograms evaluated by a core laboratory for ST-segment deviation resolution 60 minutes after treatment. Patients were categorized into 4 groups: complete resolution (>70%), partial resolution (<70% to 30%), no resolution (<30%), and worsening ST-segment deviation. Patients treated with reteplase or a combination of reteplase plus abciximab had similar rates of complete resolution (32% vs 34%), partial resolution (29% vs 27%), no resolution (15% vs 16%), and worsening ST-segment elevation (23 vs 23%; p = 0.59). The 30-day mortality rates in these 4 groups were 2.1%, 5.2%, 5.5%, and 8.1% (p <0.001). Even after accounting for baseline variables, incomplete ST-segment resolution (<70%) was associated with an increased risk of death within 30 days (adjusted hazard ratio 2.41, 95% confidence interval 1.25 to 4.63, p <0.008). Thus, ST-segment resolution at 60 minutes was no different in patients treated with full-dose reteplase from those treated with a combination of abciximab and reteplase. Patients with >70% ST-segment resolution within 60 minutes had markedly decreased mortality rates, irrespective of treatment.

Abciximab↗
PubMed2004

Global risk scores and exercise testing for predicting all-cause mortality in a preventive medicine program.

CONTEXT: The usefulness of exercise stress test results and global cardiovascular risk systems for predicting all-cause mortality in asymptomatic individuals seen in clinical settings is unclear. OBJECTIVES: To determine the validity for prediction of all-cause mortality of the Framingham Risk Score and of a recently described European global scoring system Systematic Coronary Risk Evaluation (SCORE) for cardiovascular mortality among asymptomatic individuals evaluated in a clinical setting and to determine the potential prognostic value of exercise stress testing once these baseline risks are known. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study of 3554 asymptomatic adults between the ages of 50 and 75 years who underwent exercise stress testing as part of an executive health program between October 1990 and December 2002; participants were followed up for a mean of 8 years. MAIN OUTCOME MEASURES: Global risk based on the Framingham Risk Score and the European SCORE. Prospectively recorded exercise stress test result abnormalities included impaired physical fitness, abnormal heart rate recovery, ventricular ectopy, and ST-segment abnormalities. The primary end point was all-cause mortality. RESULTS: There were 114 deaths. The c-index, which corresponds to receiver operating characteristic curve values, and the Akaike Information Criteria found that the European SCORE was superior to the Framingham Risk Score in estimating global mortality risk. In a multivariable model, independent predictors of death were a higher SCORE (for 1% predicted increase in absolute risk, relative risk [RR], 1.07; 95% confidence interval [CI], 1.04-1.09; P<.001), impaired functional capacity (RR, 2.95; 95% CI, 1.98-4.39; P<.001), and an abnormal heart rate recovery (RR, 1.59; 95%, 1.04-2.41; P =.03). ST-segment depression did not predict mortality. Among patients in the highest tertile from the SCORE, an abnormal exercise stress test result, defined as either impaired functional capacity or an abnormal heart rate recovery, identified a mortality risk of more than 1% per year. CONCLUSION: Exercise stress testing when combined with the European global risk SCORE may be useful for stratifying risk in asymptomatic individuals in a comprehensive executive health screening program.

Aged↗
PubMed2004

Prognostic importance of presenting symptoms in patients undergoing exercise testing for evaluation of known or suspected coronary disease.

PURPOSE: Chest symptoms, along with standard cardiovascular risk factors, are commonly factored into pretest risk stratification of patients who are referred for stress testing. We sought to determine the independent prognostic value of chest symptoms. METHODS: We studied the outcomes of 10,870 patients referred for symptom-limited exercise testing who had no history of myocardial revascularization, heart failure, or arrhythmias. Chest symptoms were prospectively characterized according to prespecified definitions. Propensity analysis was used to account for differences in baseline and exercise characteristics. RESULTS: Typical angina was present in 635 patients (6%), atypical angina in 3408 (33%), nonanginal chest pain in 1805 (17%), and dyspnea in 841 (8%). The remaining 4181 patients (38%) were asymptomatic. During a mean follow-up of 4.3 years, there were 381 deaths. After propensity matching patients who had typical angina with asymptomatic patients, symptoms were not predictive of mortality (adjusted hazard ratio [HR] = 0.8; 95% confidence interval [CI]: 0.6 to 1.3; P = 0.4). Among patients who had chest pain, typical angina was associated with a highly significant risk of mortality as compared with nonanginal chest pain (HR = 2.7; 95% CI: 1.4 to 5.1; P = 0.002), but not compared with atypical angina (HR = 1.3; 95% CI: 0.9 to 2.1; P = 0.21). CONCLUSION: After accounting for baseline and exercise characteristics, the presence of symptoms was not independently associated with increased mortality among patients undergoing testing for known or suspected coronary disease. Among patients who actually had chest pain, typical angina carried a higher mortality risk.

Aged↗
PubMed2004

Predictors of mortality in patients with heart failure and preserved systolic function in the Digitalis Investigation Group trial.

OBJECTIVES: We identified predictors of mortality in patients with preserved ejection fraction (EF) and clinical heart failure (HF). BACKGROUND: Although diastolic HF is common, the factors that predict mortality have not been clearly defined. METHODS: We studied 988 patients with HF and preserved EF enrolled in the Digitalis Investigation Group (DIG) trial. Survival analyses were employed to identify variables associated with mortality. RESULTS: During 3.1 years of follow-up, 231 (23%) patients died. Among 18 variables considered, the strongest independent predictors of death were glomerular filtration rate (adjusted hazard ratio for one standard deviation decrease 1.50, 95% confidence interval [CI] 1.35 to 1.67, p < 0.0001), New York Heart Association functional class III or IV (adjusted hazard ratio 1.64, 95% CI 1.20 to 2.18, p = 0.0011), male gender (adjusted hazard ratio 1.71, 95% CI 1.26 to 2.32, p = 0.0005), and older age (adjusted hazard ratio for one standard deviation increase of age2 1.28, 95% CI 1.08 to 1.50, p = 0.0019). A risk score was developed to estimate long-term mortality. CONCLUSIONS: Diastolic HF is associated with a high death rate. Important predictors of death include impaired renal function, worse functional class, male gender, and older age.

Aged↗
PubMed2004

Severe frequent ventricular ectopy after exercise as a predictor of death in patients with heart failure.

OBJECTIVES: The study was done to determine the prognostic importance of frequent ventricular ectopy in recovery after exercise among patients with systolic heart failure (HF). BACKGROUND: Although ventricular ectopy during recovery after exercise predicts death in patients without HF, its prognostic importance in patients with significant ventricular dysfunction is unknown. METHODS: Systematic electrocardiographic data during rest, exercise, and recovery were gathered on 2,123 consecutive patients with left ventricular systolic ejection fraction <or=35% who were referred for symptom-limited metabolic treadmill exercise testing. Severe ventricular ectopy was defined as the presence of ventricular triplets, sustained or nonsustained ventricular tachycardia, ventricular flutter, polymorphic ventricular tachycardia, or ventricular fibrillation. The primary end point was all-cause mortality, with censoring for interval cardiac transplantation. RESULTS: Of 2,123 patients, 140 (7%) had severe ventricular ectopy during recovery. There were 530 deaths (median follow-up among survivors 2.9 years). Severe ventricular ectopy during recovery was associated with an increased risk of death (three-year death rates 37% vs. 22%, hazard ratio [HR] 1.76; 95% confidence interval [CI] 1.32 to 2.34, p < 0.0001). After adjustment for ventricular ectopy at rest and during exercise, peak oxygen uptake, and other potential confounders, severe ventricular ectopy during recovery remained predictive of death (adjusted HR 1.48; 95% CI 1.10 to 1.97; p = 0.0089), whereas ventricular ectopy during exercise was not predictive of death in this cohort. CONCLUSIONS: Severe ventricular ectopy during recovery after exercise is predictive of increased mortality in patients with severe HF and can be used as a prognostic indicator of adverse outcomes in HF cohorts.

Cohort Studies↗
PubMed2004

Propensity analysis of long-term survival after surgical or percutaneous revascularization in patients with multivessel coronary artery disease and high-risk features.

BACKGROUND: Although most randomized clinical trials have suggested that long-term survival rates after percutaneous coronary intervention (PCI) or surgical multivessel coronary revascularization (CABG) are equivalent, some post hoc analyses in high-risk groups and adjustment for severity of coronary disease have suggested higher mortality after PCI. METHODS AND RESULTS: We studied 6033 consecutive patients who underwent revascularization in the late 1990s. PCI was performed in 872 patients; 5161 underwent CABG. Half the patients had significant left ventricular dysfunction or diabetes. Propensity analysis to predict the probability of undergoing PCI according to 22 variables and their interactions was used. The C-statistic for this model was 0.90, indicating excellent discrimination between treatments. There were 931 deaths during 5 years of follow-up. The 1- and 5-year unadjusted mortality rates were 5% and 16% for PCI and 4% and 14% for CABG (unadjusted hazard ratio, 1.13; 95% CI, 1.0 to 1.4; P=0.07). PCI was associated with an increased risk of death (propensity-adjusted hazard ratio, 2.3; 95% CI, 1.9 to 2.9; P<0.0001). This difference was observed across all categories of propensity for PCI and in patients with diabetes or left ventricular dysfunction. Other independent predictors of mortality (P< or =0.01 for all) were renal dysfunction, age, diabetes mellitus, chronic lung disease, peripheral vascular disease, left main trunk stenosis, and extent of coronary disease (Duke angiographic score). CONCLUSIONS: In patients with multivessel coronary artery disease and many high-risk characteristics, CABG was associated with better survival than PCI after adjustment for risk profile.

Aged↗
PubMed2004

Constrictive pericarditis: etiology and cause-specific survival after pericardiectomy.

OBJECTIVES: We sought to determine the association of etiology of constrictive pericarditis (CP), pericardial calcification (CA), and other clinical variables with long-term survival after pericardiectomy. BACKGROUND: Constrictive pericarditis is the result of a spectrum of primary cardiac and noncardiac conditions. Few data exist on the cause-specific survival after pericardiectomy. The impact of CA on survival is unclear. METHODS: A total of 163 patients who underwent pericardiectomy for CP over a 24-year period at a single surgical center were studied. Constrictive pericarditis was confirmed by the surgical report. Vital status was obtained from the Social Security Death Index. RESULTS: Etiology of CP was idiopathic in 75 patients (46%), prior cardiac surgery in 60 patients (37%), radiation treatment in 15 patients (9%), and miscellaneous in 13 patients (8%). Median follow-up among survivors was 6.9 years (range 0.8 to 24.5 years), during which time there were 61 deaths. Perioperative mortality was 6%. Idiopathic CP had the best prognosis (7-year Kaplan-Meier survival: 88%, 95% confidence interval [CI] 76% to 94%) followed by postsurgical (66%, 95% CI 52% to 78%) and postradiation CP (27%, 95% CI 9% to 58%). In bootstrap-validated proportional hazards analyses, predictors of poor overall survival were prior radiation, worse renal function, higher pulmonary artery systolic pressure (PAP), abnormal left ventricular (LV) systolic function, lower serum sodium level, and older age. Pericardial calcification had no impact on survival. CONCLUSIONS: Long-term survival after pericardiectomy for CP is related to underlying etiology, LV systolic function, renal function, serum sodium, and PAP. The relatively good survival with idiopathic CP emphasizes the safety of pericardiectomy in this subgroup.

Adult↗
PubMed2004

Usefulness of plasma brain natriuretic peptide levels in predicting dobutamine-induced myocardial ischemia.

Plasma brain natriuretic peptide (BNP) levels have been associated with left ventricular dysfunction and acute myocardial infarction. Although natriuretic peptide responses have been linked to exercise-induced myocardial ischemia, it is not known whether BNP levels predict dobutamine-induced myocardial ischemia. The aim of this study was to determine whether elevations in BNP levels immediately before or after dobutamine-induced stress are associated with echocardiographic myocardial ischemia. Plasma BNP was measured before and after stress during dobutamine-stress echocardiography in 317 patients (aged 68 +/- 11 years; 46% women) who had creatinine <1.5 mg/dl and did not have valvular disease. Ischemia, as assessed by blinded echocardiographic interpretation, was noted in 31 patients (10%). In univariable analyses, prestress BNP was predictive of echocardiographic ischemia (rates of ischemia according to tertiles of BNP 4%, 9%, and 16%, chi-square for trend = 8, p = 0.0059). The change in BNP levels with dobutamine stress was not associated with ischemia. In multivariable analyses, after adjusting for age, gender, and left ventricular ejection fraction, BNP before and after stress remained predictive of ischemia (1 SD increase in the log of resting BNP adjusted odds ratio 2.0, 95% confidence interval 1.3 to 3.0, p = 0.002). In this pilot study, resting BNP was predictive of dobutamine-induced ischemia. Future work is needed to confirm these findings.

Aged↗
PubMed2004

Is systolic blood pressure recovery after exercise a predictor of mortality?

BACKGROUND: An attenuated systolic blood pressure recovery after exercise has been associated with the severity of atherosclerotic heart disease. METHODS: For 6 years, we observed 12,379 patients who underwent symptom-limited exercise testing. We excluded patients receiving antihypertensive medication and patients with valvular disease, emphysema, end-stage renal disease, heart failure, left ventricular systolic dysfunction, and atrial fibrillation. Blood pressure recovery ratio was defined as the ratio of systolic blood pressure at 3 minutes into recovery to systolic blood pressure at peak exercise; this has been shown to correlate with angiographic severity of coronary disease. RESULTS: The blood pressure recovery ratios ranged from 0.36 to 1.62, with values for increasing quartiles of 0.72 +/- 0.05, 0.82 +/- 0.02, 0.88 +/- 0.02, and 0.99 +/- 0.07. During follow-up, there were 430 deaths (3%). Five-year Kaplan Meier survival rates were 0.975, 0.974, 0.969, and 0.966 in quartiles 1 to 4, respectively. Compared with patients in the lowest quartile of blood pressure recovery ratio, patients in the highest quartile were at somewhat increased risk (hazard ratio, 1.71; 95% CI, 1.31-2.24; P <.001). However, after adjusting for age, sex, body mass index, resting heart rate and blood pressure, peak systolic blood pressure, heart rate recovery, exercise chronotropic response, cardiac history, and standard risk factors, this association was no longer present (adjusted hazard ratio, 1.05; 95% CI, 0.8-1.38; P =.74). CONCLUSIONS: In this low-risk population, abnormal systolic blood pressure recovery after exercise was not independently predictive of mortality after correcting for differences in baseline and exercise characteristics.

Blood Pressure↗