Biomedical subjects
Publications and source records attributed to Michael S Lauer.
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OBJECTIVES: The purpose of this study was to develop 30-day and 1-year risk stratification models for non-ST-segment elevation acute coronary syndrome (NSTE-ACS) patients that incorporate quantitative ST-segment depression and novel biomarkers. BACKGROUND: Several novel biomarkers have changed the risk profile of ACS; thus, the reassessment of traditional indicators such as ST-segment depression in this new context is warranted. METHODS: Multivariable logistic regression was used to identify significant predictors of 30-day death and death/myocardial infarction (MI) and 1-year mortality in 7,800 NSTE-ACS patients enrolled in the GUSTO-IV (Global Utilization of Strategies to Open Occluded Arteries-IV ACS) trial between 1998 and 2000. RESULTS: Among all other predictors, the degree of ST-segment depression had the highest prognostic value for 30-day death, 30-day death/MI, and 1-year death. Troponin T (TnT), creatinine clearance, N-terminal pro-brain natriuretic peptide (NT-proBNP), heart rate, and age were also highly influential on adverse outcomes. Unlike TnT and NT-proBNP, C-reactive protein was only predictive of long-term death. In contrast to mortality, the contribution of TnT to predicting 30-day death/MI increased, whereas NT-proBNP's role was attenuated. The discriminatory power was excellent (c-index [adjusted for over-optimism]: 0.82 [30-day death]; 0.72 [30-day death/MI]; 0.81 [1-year]). CONCLUSIONS: In this large contemporary study of NSTE-ACS patients, novel insights into risk stratification were observed-in particular, the utility of quantitative ST-segment depression and multiple biomarkers. Collection of these indicators in future NSTE-ACS populations is recommended to evaluate generalizability and clinical application of these findings.
AIMS: An entity of patients with mixed physiology of constriction and restriction has been reported, however, the characteristics of these patients have not been well documented. We evaluated the clinical features and the outcome of these patients. METHODS AND RESULTS: Study subjects consisted of 38 patients (57+/-14 years, 8 females, 30 males) who were diagnosed as having mixed physiology based on transthoracic and/or transesophageal echocardiography, MRI (or CT), cardiac catheterization, endomyocardial biopsy and/or surgical findings. Prior radiation therapy was the most frequent (50%) cause of mixed physiology followed by coronary artery bypass graft without prior radiation (24%) and heart transplantation (8%). The respiratory variation of peak early diastolic transmitral flow velocity by pulsed Doppler transesophageal echocardiography was 10.7% in patients with sinus rhythm and 18.1% in patients with atrial arrhythmia. Pericardial thickening was noted adjacent to the right-sided chambers in 19 patients, left-sided chambers in 10 patients, or both in 9 patients. All-cause 5-year mortality was 40% and unrelated to age, etiology, left ventricular systolic function and therapeutic course. There was a statistically significant difference (p<0.01) between the survival rates in patients with mixed physiology and in patients with pure constriction (n=125). CONCLUSIONS: Due to the high mortality in this disease, discrimination of the entity from the patients with pure constriction is mandatory. Transthoracic and transesophageal echocardiography are helpful noninvasive techniques in the diagnosis and the understanding of the physiology of patients with mixed constriction and restriction.
CONTEXT: Lower socioeconomic status (SES) confers heightened cardiovascular risk and mortality, although the mediating pathways are unclear. OBJECTIVE: To evaluate the extent to which exercise physiologic characteristics account for the association between lower SES and mortality. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study of 30 043 consecutive patients living in 7 counties in northeast Ohio referred between 1990 and 2002 for symptom-limited stress testing for evaluation of known or suspected coronary artery disease. Follow-up for mortality continued through February 2004. MAIN OUTCOME MEASURES: Estimated functional capacity in metabolic equivalents and heart rate recovery, physiologic characteristics that are determined directly from exercise; testing and all-cause mortality during a median follow-up of 6.5 years. RESULTS: Multivariable models adjusting for demographics, insurance status, smoking status, and clinical confounders demonstrated a strong association between a composite SES score based on census block data and functional capacity (adjusted odds ratio comparing 25th with 75th percentile values, 1.72; 95% confidence interval [CI], 1.56-1.89; P<.001) as well as heart rate recovery (adjusted odds ratio comparing 25th with 75th percentile values, 1.18; 95% CI, 1.07-1.30; P<.001). There were 2174 deaths, with mortality risk increasing from 5% to 10% as SES decreased by quartile (P<.001). Cox proportional hazards models that included all confounding variables except exercise physiologic characteristics demonstrated increased mortality as SES decreased (adjusted hazard ratio comparing 25th with 75th percentile values, 1.32; 95% CI, 1.22-1.42; P<.001). After further adding functional capacity and heart rate recovery, the magnitude of this relationship was reduced (comparing 25th with 75th percentile values; adjusted hazard ratio, 1.17; 95% CI, 1.08-1.26; P<.001), with these variables explaining 47% of the association. CONCLUSIONS: Impaired functional capacity and abnormal heart rate recovery were strongly associated with lower SES and accounted for a major proportion of the correlation between SES and mortality. Efforts to modify these clinical features among patients with low SES may narrow disparities in mortality.
BACKGROUND: The clinical value of revascularization and other procedures in patients with severe systolic heart failure is unclear. It has been suggested that assessing ischemia and viability by positron emission tomography (PET) with fluorodeoxyglucose (FDG) imaging may identify patients for whom revascularization may lead to improved survival. We performed a propensity analysis to determine whether there might be a survival advantage from revascularization. METHODS AND RESULTS: We analyzed the survival of 765 consecutive patients (age 64+/-11 years, 80% men) with advanced left ventricular systolic dysfunction (ejection fraction < or =35%) and without significant valvular heart disease who underwent PET/FDG study at the Cleveland Clinic between 1997 and 2002. Early intervention was defined as any cardiac intervention (surgical or percutaneous) within the first 6 months of the PET/FDG study. In the entire cohort, 230 patients (30%) underwent early intervention (188 [25%] had open heart surgery, most commonly coronary artery bypass grafting, and 42 [5%] had percutaneous revascularization); 535 (70%) were treated medically. Using 39 demographic, clinical and PET/FDG variables, we were able to propensity-match 153 of the 230 patients with 153 patients who did not undergo early intervention. Among the propensity-matched group, there were 84 deaths during a median of 3 years follow-up. Early intervention was associated with a markedly lower risk of death (3-year mortality rate of 15% versus 35%, propensity adjusted hazard ratio 0.52, 95% CI 0.33 to 0.81, P=0.0004). CONCLUSIONS: Among systolic heart failure patients referred for PET/FDG, early intervention may be associated with improved survival irrespective of the degree of viability.
OBJECTIVES: Exercise-induced QT/RR hysteresis exists when, for a given R-R interval, the QT interval duration is shorter during recovery after exercise than during exercise. We sought to assess the association between QT/RR hysteresis and imaging evidence of myocardial ischemia. BACKGROUND: Because ischemia induces cellular disturbances known to decrease membrane action potential duration, we hypothesized a correlation between QT/RR and myocardial ischemia. METHODS: We digitally analyzed 4-second samples of QT duration and R-R-interval duration in 260 patients referred for treadmill exercise stress and rest single photon emission computed tomography myocardial perfusion imaging; a cool-down period was used after exercise. None of the patients were in atrial fibrillation or used digoxin, and none had marked baseline electrocardiographic abnormalities. Stress and rest myocardial perfusion images were analyzed visually and quantitatively to define the extent and severity of stress-induced ischemia. QT/RR hysteresis was calculated using a computerized algorithm. RESULTS: There were 82 patients (32%) who manifested myocardial ischemia by single photon emission computed tomography myocardial perfusion imaging. The likelihood of ischemia increased with increasing QT/RR hysteresis, with prevalence according to quartiles of 20%, 30%, 26%, and 49% (P = .003 for trend). In analyses adjusting for ST-segment changes, exercise capacity, heart rate recovery, and other confounders, QT/RR hysteresis was independently predictive of presence of myocardial ischemia (adjusted odds ratio for 100-point increase of QT/RR hysteresis, 1.61; 95% confidence interval, 1.22-2.12; P = .0008). QT/RR hysteresis was also predictive of severe ischemia. CONCLUSION: Exercise-induced QT/RR hysteresis is a strong and independent predictor of myocardial ischemia and provides additional information beyond that afforded by standard ST-segment measures.
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Ultrasonography can screen for abdominal aortic aneurysms (AAAs) safely, cheaply, and accurately. Once detected, an AAA can be monitored and repaired before it is likely to rupture. The US Preventive Services Task Force recently recommended a one-time screening for AAAs by ultrasonography for men age 65 to 75 years who have ever smoked. We should consider expanding the recommendations to include others at risk.
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AIMS: The optimal revascularization strategy in patients with symptomatic multivessel coronary artery disease (CAD) and previous coronary artery bypass grafting (CABG) remains unknown. METHODS AND RESULTS: We evaluated all patients with previous CABG undergoing isolated, non-emergency multivessel revascularization between 1 January 1995 and 31 December 2000. The analysis concentrated on the independent predictors of the revascularization method, as well as on long-term mortality and its predictors, after calculating a propensity score for the method of revascularization. There were 2191 patients (1487 with reoperation and 704 with percutaneous coronary intervention, PCI) in the study. The most important factors in choosing reoperation were presence of more diseased or occluded grafts, previous infarction, lower ejection fraction (EF), longer interval from first CABG, and more total occlusions of native arteries, as well as absence of a patent mammary graft. The distribution of the propensity score was skewed towards the two extremes. At 5 years, the unadjusted cumulative survival was 79.5% for CABG and 75.3% for PCI, P=0.008. After adjustment for the propensity score for PCI vs. CABG, PCI was associated with a hazard ratio of 1.47 (0.94-2.28), P=0.09. The most powerful predictors of mortality were higher age and lower EF. CONCLUSION: The choice of the revascularization method in patients with previous CABG is dictated mostly by anatomical considerations and less by clinical characteristics. In contrast, clinical characteristics predominantly affect long-term outcome, whereas the method of revascularization has a limited effect. A randomized clinical trial addressing this important segment of the population with ischaemic heart disease is warranted.
Chronotropic incompetence, or an inability to increase heart rate during exercise, independently predicts death in patients not taking beta blockers. Whether it predicts death in patients taking beta blockers is not known. Consecutive patients (n = 3,736; mean age 58 +/- 11 years; 68% men), who were taking either metoprolol tartrate or atenolol and were referred for symptom-limited exercise testing from 1990 to 2002 at a major academic medical center, formed the prospective study cohort. None had heart failure, pacemakers, atrial fibrillation, or any electrocardiographic abnormalities. Patients were followed for a median of 4.5 years for all-cause mortality. Chronotropic response was defined as the percentage of heart rate reserve used. A value of < or =62%, which was noted in 813 patients (22%), was considered abnormal, meaning that chronotropic incompetence was present. There were 173 deaths. After adjusting for age, gender, heart rate at rest, standard risk factors, other medications, Duke treadmill score, and heart rate recovery, chronotropic incompetence predicted death (adjusted hazard ratio 1.94, 95% confidence interval 1.43 to 2.64, p <0.0001). The association of chronotropic incompetence with death was present, irrespective of which drug was taken or the number of half-lives that had elapsed since the last dose. In conclusion, in patients taking beta blockers, chronotropic incompetence is independently predictive of death.
We compared a novel strategy of carotid stenting (CS) followed by open heart surgery (OHS) to the combined carotid endarterectomy (CEA) and the OHS approach in patients requiring coronary and carotid revascularization. Between 1997 and 2002, CS as a prelude to OHS was performed in 56 patients, and 111 patients underwent combined CEA+OHS. Adverse events included stroke, myocardial infarction (MI), death, and their combinations. At baseline, the CS+OHS group had more unstable/severe angina (52% vs 27%, p = 0.002), severe left ventricular dysfunction (20% vs 9%, p = 0.05), symptomatic carotid disease (46% vs 23%, p = 0.002), and the need for repeat OHS (32% vs 9%, p = 0.0002). Severe contralateral carotid disease was more prevalent in the CEA+OHS group (28% vs 11%, p = 0.01). At 30 days, CS+OHS patients had a significantly lower incidence of stroke or MI (5% vs 19%, p = 0.02). A propensity score was created for each patient to account for baseline differences. In a final logistic regression model that included the propensity score, CS+OHS was associated with a trend toward reduced stroke or MI (odds ratio 0.26, 95% confidence interval 0.06 to 1.09, p = 0.06) and reduced death, stroke, or MI (odds ratio 0.40, 95% confidence interval 0.12 to 1.27, p = 0.12). In conclusion, despite a higher baseline risk profile, patients who underwent CS+OHS had significantly fewer adverse events than those undergoing CEA+OHS. CS may be a safer carotid revascularization option for this challenging patient population.
BACKGROUND: Recent studies have demonstrated that exercise capacity is an independent predictor of mortality in women. Normative values of exercise capacity for age in women have not been well established. Our objectives were to construct a nomogram to permit determination of predicted exercise capacity for age in women and to assess the predictive value of the nomogram with respect to survival. METHODS: A total of 5721 asymptomatic women underwent a symptom-limited, maximal stress test. Exercise capacity was measured in metabolic equivalents (MET). Linear regression was used to estimate the mean MET achieved for age. A nomogram was established to allow the percentage of predicted exercise capacity to be estimated on the basis of age and the exercise capacity achieved. The nomogram was then used to determine the percentage of predicted exercise capacity for both the original cohort and a referral population of 4471 women with cardiovascular symptoms who underwent a symptom-limited stress test. Survival data were obtained for both cohorts, and Cox survival analysis was used to estimate the rates of death from any cause and from cardiac causes in each group. RESULTS: The linear regression equation for predicted exercise capacity (in MET) on the basis of age in the cohort of asymptomatic women was as follows: predicted MET = 14.7 - (0.13 x age). The risk of death among asymptomatic women whose exercise capacity was less than 85 percent of the predicted value for age was twice that among women whose exercise capacity was at least 85 percent of the age-predicted value (P<0.001). Results were similar in the cohort of symptomatic women. CONCLUSIONS: We have established a nomogram for predicted exercise capacity on the basis of age that is predictive of survival among both asymptomatic and symptomatic women. These findings could be incorporated into the interpretation of exercise stress tests, providing additional prognostic information for risk stratification.
The prognostic values of tissue Doppler imaging and color M-mode diastolic indexes were studied in 225 patients who had symptomatic systolic heart failure in the ADEPT study. The primary end point of death, transplantation, or hospitalization due to heart failure occurred in 65 patients and was independently predicted by shorter deceleration time, lower ratio of pulmonary vein systolic to diastolic velocity, and increasing levels of the ratios of early transmitral velocity to early annular velocity or velocity of propagation. For the ratio of early transmitral velocity to early annular velocity, this prediction was additive to deceleration time. Newer diastolic indexes provide an independent prediction of clinical outcomes.
Although it is well established that a blunted chronotropic response to exercise is associated with a higher risk of death, recent data suggest a similar association between mortality risk and blunted heart rate response to vasodilatory stress. We investigated the heart rate response to dipyridamole-induced stress as a predictor of death in the setting of normal myocardial perfusion and a normal electrocardiogram. We followed 1,087 patients for 8 years (range 5.7 to 11.8) who underwent dipyridamole vasodilator stress and had normal perfusion scans and electrocardiograms. None had heart failure, known left ventricular systolic dysfunction, pacemaker implantation, or valve disease. Heart rate response was assessed as the ratio of heart rate at peak stress to heart rate at rest. The primary end point was all-cause mortality. Quartile values for the peak-to-rest heart rate ratio were <1.19, 1.19 to 1.30, 1.31 to 1.44, and >1.44. There were 246 deaths. Death rates according to quartiles of heart rate ratio were 103 of 271 (38%), 64 of 272 (24%), 52 of 272 (19%), and 27 of 272 (10%). After adjusting for age, gender, heart rate at rest, blood pressure response, standard cardiovascular risk factors, and other confounders, a blunted heart rate response remained predictive of death (adjusted hazard ratio for lowest vs highest quartile 3.3, 95% confidence interval 2.1 to 5.1, p <0.0001). When considered as a continuous variable, the logarithm of the heart rate ratio was the strongest predictor of death, aside from age. Thus, among patients who have normal myocardial perfusion and normal electrocardiograms, a blunted heart rate response to vasodilator stress is predictive of a marked increase in risk of death.
BACKGROUND: Peak oxygen uptake (peak VO2) is a strong predictor of mortality and is commonly used in the evaluation of patients for cardiac transplantation. Beta-blockers reduce mortality in patients with heart failure, without influencing peak VO2, raising the possibility that peak VO2 is no longer suitable as an indicator of prognosis in these patients. METHODS AND RESULTS: We analyzed prospectively gathered data on 2105 patients referred for cardiopulmonary testing for all-cause mortality and for occurrence of death or transplantation. Patients receiving beta-blockers were younger, more likely to have coronary disease, and had a greater mean ejection fraction but had a similar peak VO2. There were 555 deaths (26%) and 194 (9%) transplants during a median follow-up of 3.5 years. Peak VO2 was a predictor of mortality irrespective of beta-blocker use; a decrease of 1 mL x kg(-1) x min(-1) resulted in an adjusted hazard ratio (HR) of 1.13 (95% CI 1.09 to 1.17, P<0.0001) in patients not receiving beta-blockers and 1.27 (95% CI 1.18 to 1.36, P<0.0001) in patients receiving beta-blockers. Similar findings were noted when considering death or transplantation as an end point. Beta-blocker use was associated with better outcomes until peak VO2 values became very low (approximately 10 mL x kg(-1) x min(-1)), at which level survival rates were equally poor. CONCLUSION: Peak VO2 is a determinant of survival in patients in heart failure even in the setting of beta-blockade. Because of improved survival in patients treated with beta-blockers, the cut point value of 14 mg x kg(-1) x min(-1) for referral for cardiac transplantation in these patients requires reevaluation, and a lower cut point may be more appropriate.