Patient-Centered Network of Learning Health Systems: Developing a resource for clinical translational research.

INTRODUCTION: The Learning Health System Network clinical data research network includes academic medical centers, health-care systems, public health departments, and health plans, and is designed to facilitate outcomes research, pragmatic trials, comparative effectiveness research, and evaluation of population health interventions. METHODS: The Learning Health System Network is 1 of 13 clinical data research networks assembled to create, in partnership with 20 patient-powered research networks, a National Patient-Centered Clinical Research Network. RESULTS AND CONCLUSIONS: Herein, we describe the Learning Health System Network as an emerging resource for translational research, providing details on the governance and organizational structure of the network, the key milestones of the current funding period, and challenges and opportunities for collaborative science leveraging the network.

Risk of myocardial infarction and stroke in bipolar disorder: a systematic review and exploratory meta-analysis.

OBJECTIVE: To review the evidence on and estimate the risk of myocardial infarction and stroke in bipolar disorder. METHOD: A systematic search using MEDLINE, EMBASE, PsycINFO, Web of Science, Scopus, Cochrane Database of Systematic Reviews, and bibliographies (1946 - May, 2013) was conducted. Case-control and cohort studies of bipolar disorder patients age 15 or older with myocardial infarction or stroke as outcomes were included. Two independent reviewers extracted data and assessed quality. Estimates of effect were summarized using random-effects meta-analysis. RESULTS: Five cohort studies including 13 115 911 participants (27 092 bipolar) were included. Due to the use of registers, different statistical methods, and inconsistent adjustment for confounders, there was significant methodological heterogeneity among studies. The exploratory meta-analysis yielded no evidence for a significant increase in the risk of myocardial infarction: [relative risk (RR): 1.09, 95% CI 0.96-1.24, P = 0.20; I(2)  = 6%]. While there was evidence of significant study heterogeneity, the risk of stroke in bipolar disorder was significantly increased (RR 1.74, 95% CI 1.29-2.35; P = 0.0003; I(2)  = 83%). CONCLUSION: There may be a differential risk of myocardial infarction and stroke in patients with bipolar disorder. Confidence in these pooled estimates was limited by the small number of studies, significant heterogeneity and dissimilar methodological features.

Risk of cardiovascular events in patients with polycystic ovary syndrome.

Women with polycystic ovary syndrome (PCOS) have increased prevalence of cardiovascular (CV) risk factors. However, data on the incidence of CV events are lacking in this population. Using Rochester Epidemiology Project resources, we conducted a retrospective cohort study comparing CV events in women with PCOS with those of women without PCOS in Olmsted County, Minnesota. Between 1966 and 1988, 309 women with PCOS and 343 without PCOS were identified. Mean (SD) age at PCOS diagnosis was 25.0 (5.3) years; mean age at last follow-up was 46.7 years. Mean (SD) follow-up was 23.7 (13.7) years. Women with PCOS had a higher body mass index (29.4 kg÷m2 vs 28.3 kg÷m2; p=.01). Prevalence of type 2 diabetes mellitus and hypertension and levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglycerides were similar in the two groups. We observed no increase in CV events, including myocardial infarction (adjusted hazard ratio [HR] 0.74; 95% confidence interval [CI] 0.32 to 1.72; p=.48); coronary artery bypass graft surgery (adjusted HR 1.52; 95% CI 0.42 to 5.48; p=.52); death (adjusted HR 1.03; 95% CI, 0.29 to 3.71; p=.96); death due to CV disease (adjusted HR 5.67; 95% CI 0.51 to 63.7; p=.16); or stroke (adjusted HR 1.05; 95% CI 0.28 to 3.92; p=.94). Although women with PCOS weighed more than controls, there was no increased prevalence of other CV risk factors. Furthermore, we found no increase in CV events. While prospective studies are needed to confirm these findings, women with PCOS do not appear to have adverse CV outcomes in midlife.

Comorbid conditions and outcomes after percutaneous coronary intervention.

OBJECTIVE: To evaluate whether adding comorbid conditions to a risk model can help predict in-hospital outcome and long-term mortality after percutaneous coronary intervention (PCI). DESIGN: Retrospective chart review SETTING: Academic medical centre. PATIENTS: 7659 patients who had 9032 PCIs. INTERVENTIONS: PCI performed at Mayo Clinic between 1 January 1999 and 30 June 2004. MAIN OUTCOME MEASURES: The Mayo Clinic Risk Score (MCRS) and the coronary artery disease (CAD)-specific index for determination of comorbid conditions in all patients. RESULTS: The mean (SD) MCRS score was 6.5 (2.9). The CAD-specific index was 0 or 1 in 46%, 2 or 3 in 30% and 4 or higher in 24%. The rate of in-hospital major adverse cardiovascular events (MACE) increased with higher MCRS and CAD-specific index (Cochran-Armitage test, p<0.001 for both models). The c-statistic for the MCRS for in-hospital MACE was 0.78; adding the CAD-specific index did not improve its discriminatory ability for in-hospital MACE (c-statistic = 0.78; likelihood ratio test, p = 0.29). A total of 707 deaths after dismissal occurred after 7253 successful procedures. The c-statistic for all-cause mortality was 0.69 for the MCRS model alone and 0.75 for the MCRS and CAD-specific indices together (likelihood ratio test, p<0.001), indicating significant improvement in the discriminatory ability. CONCLUSIONS: Addition of comorbid conditions to the MCRS adds significant prognostic information for post-dismissal mortality but adds little prognostic information about in-hospital complications after PCI. Such health-status measures should be included in future risk stratification models that predict long-term mortality after PCI.

Do cardiovascular risk factors confer the same risk for cardiovascular outcomes in rheumatoid arthritis patients as in non-rheumatoid arthritis patients?

OBJECTIVE: To compare the frequency of traditional cardiovascular (CV) risk factors in rheumatoid arthritis (RA) compared to non-RA subjects, and examine their impact on the risk of developing selected CV events (myocardial infarction (MI), heart failure (HF) and CV death) in these two groups. METHODS: We examined a population-based incidence cohort of subjects with RA (defined according to the 1987 American College of Rheumatology criteria), and an age- and sex-matched non-RA cohort. All subjects were followed longitudinally through their complete community medical records, until death, migration, or 1 January 2001. Clinical CV risk factors and outcomes were defined using validated criteria. The chi2 test was used to compare the frequency of each CV risk factor at baseline. Person-years methods were used to estimate the rate of occurrence of each CV risk factor during follow-up. Cox models were used to examine the influence of CV risk factors on the development of CV outcomes. RESULTS: A total of 603 RA and 603 non-RA subjects (73% female; mean age 58 years) were followed for a mean of 15 and 17 years (total: 8842 and 10,101 person-years), respectively. At baseline, RA subjects were significantly more likely to be former or current smokers when compared to non-RA subjects (p<0.001). Male gender, smoking, and personal cardiac history had weaker associations with CV events among RA subjects, compared to non-RA subjects. There was no significant difference between RA and non-RA subjects in the risk imparted with respect to the other CV risk factors (ie, family cardiac history, hypertension, dyslipidaemia, body mass index, or diabetes mellitus). CONCLUSION: While some traditional CV risk factors imparted similar risk among RA compared with non-RA subjects, others (ie, male gender, smoking and personal cardiac history) imparted significantly less risk for the development of CV disease. These differences in the overall impact of traditional CV risk factors suggest that strategies to prevent CV disease and mortality focused solely on controlling traditional CV risk factors may be relatively less beneficial in RA subjects than in the general population. Further research is needed to determine optimal approaches to reducing CV morbidity and mortality in persons with RA.

Raised erythrocyte sedimentation rate signals heart failure in patients with rheumatoid arthritis.

BACKGROUND: Inflammatory markers are associated with heart failure. Patients with rheumatoid arthritis have twice the risk of heart failure compared with people without rheumatoid arthritis. OBJECTIVE: To assess whether heart failure in patients with rheumatoid arthritis is preceded by an inflammatory activation as shown by erythrocyte sedimentation rate (ESR), a systemic marker of inflammation. METHODS: A population-based inception cohort of 575 patients with rheumatoid arthritis, free of heart failure at their rheumatoid arthritis incidence date, was followed up longitudinally until death or 2001. During 15 years of follow-up, they had a median of 15 ESR tests, and 172 patients had new-onset heart failure (Framingham Heart Study criteria). The follow-up period, beginning with the rheumatoid arthritis incidence date and ending with date of the last follow-up, was divided into 6-month intervals. The proportions of patients with at least one ESR value >/=40 mm/h and with anaemia (haemoglobin <11 g/dl) within each 6-month interval were plotted against time from fulfilment of heart failure criteria. A binomial test was used to compare proportions. RESULTS: In patients with rheumatoid arthritis who developed heart failure, the proportion with ESR >/=40 mm/h was highest (23%) during the 6-month period immediately preceding the new-onset heart failure, as compared with the average ESR during the entire remaining follow-up period, both before and after heart failure (10.6%; p<0.01). The proportion of patients with anaemia peaked (54%) during the 6-month period after heart failure. CONCLUSIONS: Inflammatory stimuli may be involved in the initiation of heart failure among patients with rheumatoid arthritis.

Cardiac rehabilitation after myocardial infarction: a review to understand barriers to participation and potential solutions.

As survival after myocardial infarction (MI) improves, secondary prevention is becoming increasingly important. Cardiac rehabilitation (CR) is one modality for delivery of secondary prevention, whose ultimate goal is to help patients receive appropriate preventive therapies that will help them optimize health and reduce the risk of future cardiac diseases. However, participation rates in CR are less than optimal: in the United States, only 29.5% of MI survivors participated, in Japan 21% of those with acute MI, and in Australia 29% of those eligible were referred, and only 1/3 of those referred acutally attended CR; moreover, there does not appear to be a trend towards increasing participation over time. After reviewing the components of CR and the benefits of participation, this paper will focus on the barriers to participation in CR: from a theoretical framework to consider barriers at patient, provider, health system, and societal levels. We then explore the possible solutions to overcome them and finally propose recommendation for future research.

Gender differences and temporal trends in clinical characteristics, stress test results and use of invasive procedures in patients undergoing evaluation for coronary artery disease.

OBJECTIVES: This study examined gender differences and temporal changes in the clinical characteristics of patients referred for nuclear stress imaging, their imaging results and subsequent utilization of coronary angiography and revascularization. BACKGROUND: Gender bias may influence resource utilization in patients with coronary artery disease (CAD). No study has analyzed gender differences and time trends in patients referred for noninvasive testing and subsequent use of invasive procedures. METHODS: Between January 1986 and December 1995, 14,499 patients (5,910 women and 8,589 men) without established CAD underwent stress myocardial perfusion imaging. The clinical characteristics, imaging results, coronary angiograms and revascularization outcomes were compared in women and men over time. RESULTS: The mean pretest probability of CAD was lower in women (45%) than in men (70%) (p < 0.001). More women (69%) than men (42%) had normal nuclear images (p < 0.001). Men (17%) were more likely than women (8%) to undergo coronary angiography (p < 0.001). Male gender was independently associated with referral for coronary angiography (multivariate model: chi-square = 16, p < 0.001) but was considerably weaker than the imaging variables (summed reversibility score: chi-square = 273, p < 0.001). Revascularization was performed in more men (46% of the population undergoing angiography) than women (39%) (p = 0.01), but gender was not independently associated with referral to revascularization. There were no significant differences in clinical, imaging or invasive variables between the genders over time. CONCLUSIONS: There was little evidence for a bias against women in this study. Women were somewhat less likely to undergo coronary angiography but were referred for stress perfusion imaging more liberally. Practice patterns remained constant over this 10-year period.

Referral to autopsy: effect of antemortem cardiovascular disease: a population-based study in Olmsted County, Minnesota.

PURPOSE: Autopsy studies can provide insight into disease trends and their determinants, including data on the prevalence of atherosclerosis. However, such studies are subject to autopsy bias, which limits their generalizability to the source population. The impact of this bias on autopsy based estimates of time trends in heart disease prevalence is unknown. To report on the trends over time in autopsy rates in Olmsted County, MN, to examine the association between clinical diagnoses of cardiovascular diseases (CVDs) and referral to autopsy and how this association may have changed over time. METHODS: We examined the trends in autopsy rates between 1979 and 1994 in Olmsted County, and the association between antemortem characteristics including cardiovascular diagnoses and autopsy referral. RESULTS: From 1979 to 1994, a total of 9110 residents died in Olmsted County. The average annual autopsy rate was 30%. Autopsy rates declined from 36% in 1979 to 23% in 1994, corresponding to an average decline of 0.6%/year (p < 0.01). Referral to autopsy was positively associated with younger age, male sex, in-hospital place of death, antemortem diagnoses of myocardial infarction (MI) or peripheral vascular disease (PVD), and earlier calendar period. There was no evidence of an interaction between calendar period and any of these predictor variables. Antemortem diagnosis of heart failure was associated with a decrease in the odds of referral to autopsy over time as compared to persons without such diagnosis. CONCLUSIONS: In Olmsted County, autopsy rates, although declining over time, have remained on average approximately 30%. Antemortem diagnoses of MI or PVD are associated with autopsy referral but this association did not change over time. While the greater decline overtime in the use of autopsy observed among decedents with an antemortem diagnosis of congestive heart failure (CHF) deserves further studies, the present findings reduce the concern for bias of time trends in the prevalence of atherosclerosis by changes in the clinical characteristics of decedents referred to autopsy.

Prognostic value of exercise echocardiography in 2,632 patients > or = 65 years of age.

OBJECTIVES: We sought to determine the prognostic value of exercise echocardiography in the elderly. BACKGROUND: Limited data exist regarding the prognostic value of exercise testing in the elderly, a population which may be less able to exercise and is at increased risk of cardiac death. METHODS: Follow-up (2.9 +/- 1.7 years) was obtained in 2,632 patients > or = 65 years who underwent exercise echocardiography. RESULTS: There were 1,488 (56%) men and 1,144 (44%) women (age 72 +/- 5 years). The rest ejection fraction was 56 +/- 9%. Rest wall motion abnormalities were present in 935 patients (36%). The mean work load was 7.7 +/- 2.3 metabolic equivalents (METs) for men and 6.5 +/- 1.9 METs for women. New or worsening wall motion abnormalities developed with stress in 1,082 patients (41%). Cardiac events included cardiac death in 68 patients and nonfatal myocardial infarction in 80 patients. The addition of the exercise electrocardiogram to the clinical and rest echocardiographic model provided incremental information in predicting both cardiac events (chi-square = 77 to chi-square = 86, p = 0.003) and cardiac death (chi-square = 71 to chi-square = 86, p < 0.0001). The addition of exercise echocardiographic variables, especially the change in left ventricular end-systolic volume with exercise and the exercise ejection fraction, further improved the model in terms of predicting cardiac events (chi-square = 86 to chi-square = 108, p < 0.0001) and cardiac death (chi-square = 86 to chi-square = 99, p = 0.004). CONCLUSIONS: Exercise echocardiography provides incremental prognostic information in patients > or = 65 years of age. The best model included clinical, exercise testing and exercise echocardiographic variables.

Assessment of the exercise electrocardiogram in women versus men using tomographic myocardial perfusion imaging as the reference standard.

The exercise electrocardiogram (ECG) is widely believed to be less accurate in women, primarily due to a high prevalence of false-positive tests. The purpose of this study was to examine the relative accuracy of the exercise ECG in women versus men in 8,671 patients (3,213 women, 5,458 men) using myocardial perfusion imaging as the reference standard. More women (14%) than men (10%) had a false-positive ECG (p <0.001), but the absolute difference was relatively small. The false-negative rate was considerably lower in women (17% vs 32%, p <0.001). Compared with men, women had lower test sensitivity (30% vs 42%, p <0.001) and positive predictive value (34% vs 70%, p <0.001) but higher specificity (82% vs 78%, p = 0.002), negative predictive value (78% vs 52%, p <0.001), and accuracy (69% vs 58%, p <0.001). In patients with a false-negative exercise ECG, "high-risk" scans were less prevalent in women (12% vs 19%, p <0.001). In the smaller subset of patients referred for coronary angiography (205 women, 838 men), the false-positive electrocardiographic rate was again higher in women (13% vs 7%, p = 0.003), but neither specificity (69% vs 74%, p = NS) nor accuracy (60% vs 66%, p = NS) was different between the sexes. Thus, the percentage of patients with a false-positive exercise ECG was higher in women than men but low in absolute terms (<15%) for both sexes. Test specificity was not lower in women. These results suggest that gender should not be a major determinant for selecting stress imaging over standard treadmill testing.

Time trends in the prevalence of atherosclerosis: a population-based autopsy study.

PURPOSE: Mortality from coronary heart disease is declining but little is known about trends in the prevalence of atherosclerosis. Autopsy rates in Olmsted County, Minnesota, are higher than the national average, offering an opportunity to address this matter. In this study, we determined the prevalence of anatomic coronary disease among autopsied Olmsted County residents and examined the generalizability of these findings. SUBJECTS AND METHODS: Reports of the 2,562 autopsies performed between 1979 and 1994 on Olmsted County residents > or =20 years of age were reviewed for the presence of coronary disease. RESULTS: Among autopsied decedents less than 60 years old at death and among coroner's cases, the prevalence of anatomic coronary disease declined with time (P for trend = 0.05); no trend was detected among older persons or noncoroner's cases. By logistic regression analysis, the crude odds ratio ([OR] per 5 years) for the association between time and anatomic coronary disease was 0.94 (95% confidence interval [CI]: 0.86 to 1.03; P = 0.18]. Age, sex, and antemortem diagnosis of heart disease were also strongly related to the presence of disease. After adjustment for sex and antemortem diagnosis of heart disease, the prevalence of anatomic coronary disease decreased more in younger people than in older people (age 40 years: OR 0.43 [95% CI: 0.24 to 0.80]; age 60 years: OR 0.62 [95% CI: 0.45 to 0.87]; age 80 years: OR 0.89 [95% CI: 0.64 to 1.23]). CONCLUSION: The prevalence of anatomic coronary disease at autopsy decreased between 1979 and 1994, particularly among younger people, supporting the notion that the burden of coronary disease has shifted toward the elderly. These results suggest that the decreased incidence of coronary artery disease has contributed to the recent decrease in coronary mortality, particularly among younger people.

Impact of atropine injection on heart rate response during treadmill exercise echocardiography: a double-blind randomized pilot study.

We evaluated the effect of atropine on the heart rate (HR) response during treadmill exercise echocardiography. A potential limitation of treadmill exercise echocardiography is the requirement for postexercise imaging. Rapid recovery of HR and wall motion abnormalities may decrease test sensitivity. A double-blind randomized study was performed at a tertiary care center. Fifty-two patients (age, 63 +/- 9 years) with known or suspected coronary artery disease were injected with either 0.5 mg of atropine or saline before treadmill exercise echocardiography. HR response during and after exercise was recorded. Atropine resulted in a greater increase in HR before exercise (increase of 15 +/- 9 vs 5 +/- 7 beats per minute, P < 0.0001) and a higher HR rate during the first 5 minutes of exercise (P < 0.05). In recovery, there was an exponential decrease in HR in both atropine and control groups. However, at the end of image acquisition (66 +/- 15 seconds), the HR was higher in the atropine group (128 +/- 21 vs 115 +/- 19 beats per minute, P = 0.02) and remained higher throughout the 10-minute recovery period (P = 0.0015). Dry mouth was more common after atropine injection (P = 0.005); other side effects were similar. The extent and resolution of myocardial ischemia were comparable in both groups. Atropine injection before treadmill exercise echocardiography results in a higher HR during the acquisition of echocardiographic images; whether atropine could affect the diagnostic accuracy of tread mill exercise echocardiography requires further study.

Cardiology services after stress testing: are there sex differences? A population-based study.

To test the hypothesis that, in a population-based cohort of persons undergoing stress tests, female sex was negatively associated with the use of cardiology visits in persons with no documented coronary artery disease (CAD) but that this association did not exist when CAD was established. Sex differences in the use of invasive cardiac procedures have been clearly documented, but data on physician encounters, an integral part of care, are lacking. A population-based cohort consisting of all Olmsted County, Minnesota residents who underwent an initial stress test in 1987, 1988, and 1989 in Olmsted County was examined. Medical records were reviewed for baseline characteristics including CAD diagnosis status, test results, and cardiology visits in the year following the stress test. Regression models were constructed to determine whether sex is independently associated with the probability of a visit. In the year after stress testing, there was no difference between the sexes in the use of inpatient (OR for female sex 0.88, 95% CI 0.62-0.97, P = 0.365) and outpatient/consultative (OR for female sex 1.24, 95% CI 0.95-1.61, P = 0.6) cardiology visits. Women were, however, less likely to receive preventive cardiology visits (OR for female sex 0.77, 95% CI 0.62-0.97, P = 0.02). This was largely related to less use of preventive visits among older women with documented coronary artery disease (CAD). In the absence of documented CAD, when the stress test was positive, women were less likely to receive preventive visits. In this geographically defined population within one year after an initial stress test, there was no sex difference in the use of in-patient or out-patient visits but women were less likely to receive preventive cardiology visits in the year after stress testing. Further studies are needed to understand the reasons for and impact of these care patterns.

Validation of death certificate diagnosis of out-of-hospital coronary heart disease deaths in Olmsted County, Minnesota.

OBJECTIVE: To evaluate the validity of death certificate diagnosis of out-of-hospital (OOH) coronary heart disease (CHD) and sudden cardiac death (SCD) in Olmsted County, Minnesota, between 1981 and 1994. METHODS: In this review of the medical records, autopsy reports, and coroner's files, OOH deaths with heart disease as the underlying cause of death on the death certificate were classified into CHD (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] codes 410-414) and non-CHD (other ICD-9-CM heart disease codes) deaths. A 10% random sample (n = 174) of these death certificates was reviewed by physicians, and published validation criteria were applied to classify these deaths into validated CHD or non-CHD categories. Sudden cardiac death was defined as validated CHD that occurred at an OOH location with less than 24 hours between symptom onset and death. RESULTS: The death certificate definition of OOH CHD death (ICD-9-CM codes 410-414) had high sensitivity and positive predictive value of 91% and 96%, respectively. The specificity and the negative predictive value were slightly lower at 86% and 72%, respectively. The sensitivity of death certificate diagnosis of CHD for validated SCD was 89%, and the positive predictive value was 77%. Using a more restrictive definition of SCD, that is, less than 1 hour between the onset of symptoms and death, the positive predictive value of CHD codes for SCD was lower at 52%. CONCLUSIONS: In Olmsted County, the positive predictive values of death certificate diagnosis for OOH CHD and SCD are high. Relying on death certificate diagnoses results in about 5% underestimation of the true CHD rates, whereas their use as a surrogate for SCD yields a 16% overestimation of the true SCD rates.

Prognostic value of treadmill exercise testing in elderly persons.

BACKGROUND: Recent exercise testing guidelines recognized a gap in knowledge about the prognostic value of treadmill exercise testing in elderly persons. OBJECTIVE: To test the hypothesis that treadmill exercise testing has equal prognostic value among elderly (> or =65 years of age) and younger (<65 years of age) persons and to examine the incremental value of this testing over clinical data. DESIGN: Inception cohort with a median follow-up of 6 years. SETTING: Olmsted County, Minnesota. PATIENTS: All elderly (n = 514) and younger (n = 2593) residents of Olmsted County who underwent treadmill exercise testing between 1987 and 1989. MEASUREMENTS: Overall mortality and cardiac events (cardiac death, nonfatal myocardial infarction, and congestive heart failure). RESULTS: Compared with younger patients, elderly patients had more comorbid conditions, achieved a lower workload (6.0 and 10.7 metabolic equivalents; P < 0.001), and had a greater likelihood of a positive exercise electrocardiogram (28% and 9%; P < 0.001). With median follow-up of 6 years, overall survival (63% and 92%; P < 0.001) and cardiac event-free survival (66% and 95%; P < 0.001) were worse among elderly persons than among younger persons. Workload was the only treadmill exercise testing variable associated with all-cause mortality in both age groups, and the strength of association was similar. Workload and angina with exercise testing were associated with cardiac events in both age groups, whereas a positive exercise electrocardiogram was associated with cardiac events only in younger persons (P < 0.05 for all comparisons). After adjustment for clinical variables, workload was the only additional treadmill exercise testing variable that was predictive of death (P < 0.001) and cardiac events (P < 0.05); the strength of the association was similar in both age groups. Each 1-metabolic equivalent increase in exercise capacity was associated with a 14% and 18% reduction in cardiac events among younger and elderly persons, respectively. CONCLUSIONS: In elderly persons, treadmill exercise testing provided prognostic information that is incremental to clinical data. After adjustment for clinical factors, work-load was the only treadmill exercise testing variable that was strongly associated with outcome, and its prognostic effect was of the same magnitude in elderly and younger persons.

Assessment of cardiac risk before nonvascular surgery: dobutamine stress echocardiography in 530 patients.

OBJECTIVE: This study evaluated the incremental value of dobutamine stress echocardiography (DSE) for assessment of cardiac risk before nonvascular surgery. BACKGROUND: Limited information exists regarding the preoperative assessment of cardiac risk in patients with known or suspected coronary artery disease who are to undergo nonvascular surgery. METHODS: All patients (303 men, 227 women) who underwent DSE before nonvascular surgery and did not sustain an intervening event (coronary revascularization or cardiac event) were studied. Clinical, electrocardiographic and rest and stress echocardiographic variables were evaluated to identify predictors of postoperative cardiac events. RESULTS: Events occurred in 6% of patients: 1 cardiac death and 31 nonfatal myocardial infarctions. All of these patients had inducible ischemia on DSE (sensitivity 100%, specificity 63%). Multivariate predictors of postoperative events in patients with ischemia were history of congestive heart failure (p = 0.006; odds ratio = 4.66; confidence interval 1.55 to 14.02) and ischemic threshold less than 60% of age-predicted maximal heart rate (p = 0.0001; odds ratio 7.002; confidence interval 2.79 to 17.61). Clinical variables of Eagle's index identified 21% of patients as low, 68% as intermediate and 11% as high risk preoperatively; the postoperative event rates were 3%, 6%, and 14%, respectively. Dobutamine stress echocardiography identified 60% of patients as low (no ischemia), 32% as intermediate (ischemic threshold 60% or more) and 8% as high risk (ischemic threshold < 60%); postoperative event rates were 0%, 9% and 43%, respectively. CONCLUSIONS: In this population of patients with known or suspected coronary artery disease evaluated before nonvascular surgery, DSE had incremental value over clinical, electrocardiographic and rest echocardiographic variables for identifying patients at low, intermediate and high risk for postoperative cardiac events. Ischemia occurring at less than 60% of age-predicted maximal heart rate identified patients at highest risk.