Potential Mediators for Treatment Effects of Novel Diabetes Medications on Cardiovascular and Renal Outcomes: A Meta-Regression Analysis

BACKGROUND

Prior research suggests clinical effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) are mediated by changes in glycated hemoglobin, body weight, systolic blood pressure, hematocrit, and urine albumin-creatinine ratio. We aimed to confirm these findings using a meta-analytic approach.

METHODS AND RESULTS

We updated a systematic review of 9 GLP-1RA and 13 SGLT2i trials and summarized longitudinal mediator data. We obtained hazard ratios (HRs) for cardiovascular, renal, and mortality outcomes. We performed linear mixed-effects modeling of LogHRs versus changes in potential mediators and investigated differences in meta-regression associations among drug classes using interaction terms. HRs generally became more protective with greater glycated hemoglobin reduction among GLP-1RA trials, with average HR improvements of 20% to 30%, reaching statistical significance for major adverse cardiovascular events (ΔHR, 23%; P=0.02). Among SGLT2i trials, associations with HRs were not significant and differed from GLP1-RA trials for major adverse cardiovascular events (Pinteraction=0.04). HRs for major adverse cardiovascular events, myocardial infarction, and stroke became less efficacious (ΔHR, -15% to -34%), with more weight loss for SGLT2i but not for GLP-1RA trials (ΔHR, 4%-7%; Pinteraction<0.05). Among 5 SGLT2i trials with available data, HRs for stroke became less efficacious with larger increases in hematocrit (ΔHR, 123%; P=0.09). No changes in HRs by systolic blood pressure (ΔHR, -11% to 9%) and urine albumin-creatinine ratio (ΔHR, -1% to 4%) were found for any outcome.

CONCLUSIONS

We confirmed increased efficacy findings for major adverse cardiovascular events with reduction in glycated hemoglobin for GLP1-RAs. Further research is needed on the potential loss of cardiovascular benefits with increased weight loss and hematocrit for SGLT2i.

Cardiovascular and Renal Benefits of Novel Diabetes Drugs by Baseline Cardiovascular Risk: A Systematic Review, Meta-analysis, and Meta-regression

BACKGROUND

Eligibility for glucagon-like peptide 1 receptor agonists (GLP-1RA) and sodium-glucose cotransporter 2 inhibitors (SGLT2i) has been expanded to patients with diabetes at lower cardiovascular risk, but whether treatment benefits differ by risk levels is not clear.

PURPOSE

To investigate whether patients with varying risks differ in cardiovascular and renal benefits from GLP-1RA and SGLT2i with use of meta-analysis and meta-regression.

DATA SOURCES

We performed a systematic review using PubMed through 7 November 2022.

STUDY SELECTION

We included reports of GLP-1RA and SGLT2i confirmatory randomized trials in adult patients with safety or efficacy end point data.

DATA EXTRACTION

Hazard ratio (HR) and event rate data were extracted for mortality, cardiovascular, and renal outcomes.

DATA SYNTHESIS

We analyzed 9 GLP-1RA and 13 SGLT2i trials comprising 154,649 patients. Summary HRs were significant for cardiovascular mortality (GLP-1RA 0.87 and SGLT2i 0.86), major adverse cardiovascular events (0.87 and 0.88), heart failure (0.89 and 0.70), and renal (0.84 and 0.65) outcomes. For stroke, efficacy was significant for GLP-1RA (0.84) but not for SGLT2i (0.92). Associations between control arm cardiovascular mortality rates and HRs were nonsignificant. Five-year absolute risk reductions (0.80-4.25%) increased to 11.6% for heart failure in SGLT2i trials in patients with high risk (Pslope < 0.001). For GLP1-RAs, associations were nonsignificant.

LIMITATIONS

Analyses were limited by lack of patient-level data, consistency in end point definitions, and variation in cardiovascular mortality rates for GLP-1RA trials.

CONCLUSIONS

Relative effects of novel diabetes drugs are preserved across baseline cardiovascular risk, whereas absolute benefits increase at higher risks, particularly regarding heart failure. Our findings suggest a need for baseline risk assessment tools to identify variation in absolute treatment benefits and improve decision-making.

Evaluation of premature ventricular complexes during in-hospital ECG monitoring as a predictor of ventricular tachycardia in an intensive care unit cohort

In-hospital electrocardiographic (ECG) monitors are typically configured to alarm for premature ventricular complexes (PVCs) due to the potential association of PVCs with ventricular tachycardia (VT). However, no contemporary hospital-based studies have examined the association of PVCs with VT. Hence, the benefit of PVC monitoring in hospitalized patients is largely unknown. This secondary analysis used a large PVC alarm data set to determine whether PVCs identified during continuous ECG monitoring were associated with VT, in-hospital cardiac arrest (IHCA), and/or death in a cohort of adult intensive care unit patients. Six PVC types were examined (i.e., isolated, bigeminy, trigeminy, couplets, R-on-T, and run PVCs) and were compared between patients with and without VT, IHCA, and/or death. Of 445 patients, 48 (10.8%) had VT; 11 (2.5%) had IHCA; and 49 (11%) died. Isolated and run PVC counts were higher in the VT group (p = 0.03 both), but group differences were not seen for the other four PVC types. The regression models showed no significant associations between any of the six PVC types and VT or death, although confidence intervals were wide. Due to the small number of cases, we were unable to test for associations between PVCs and IHCA. Our findings suggest that we should question the clinical relevance of activating PVC alarms as a forewarning of VT, and more work should be done with larger sample sizes. A more precise characterization of clinically relevant PVCs that might be associated with VT is warranted.

Abstract P140: Potential Mediators for Cardiovascular Benefits of Novel Diabetes Medications: A Meta-Regression Analysis

Background: Prior research suggests cardiovascular (CV) benefits of glucose-lowering interventions may be mediated by changes in hemoglobin A1c (HbA1c), bodyweight, systolic blood pressure (SBP), hematocrit, and urine albumin-creatinine ratio (uACR). We evaluated the heterogeneity of CV benefits by these potential mediators for sodium-glucose transporter 2 inhibitors (SGLT2i) and glucagon-like peptide 1 receptor agonists (GLP-1RAs) using a meta-analytic approach.

Methods: We performed a systematic review and meta-regression analyses of 12 SGLT2i and 9 GLP-1RA CV outcome trials using linear mixed models of treatment efficacy measured as log hazard ratios (HRs) vs changes in potential mediators. We extracted follow-up mediator data for treatment and control, preferably at 12 months post randomization. Outcomes included MI, stroke, and MACE (a composite of MI, stroke, or CV death). We investigated slope differences between drug classes using interaction terms and likelihood-ratio tests.

Results: Treatment efficacy for MACE improved with more HbA1c reduction among GLP-1RA (slope .26; P slope .02) but not among SGLT2i trials (slope -.22; P slope .39; P interaction .06), see Figure . Treatment efficacy for MACE, MI, and stroke decreased with more weight loss for SGLT2i (slope –.17, –.29, –.39; P slope <.05) but not for GLP-1RA trials (slope .05, .03, .07; P slope .30, .62, .32). Slopes differed significantly between drug classes: P interaction <.05. For stroke, we observed a trend of less treatment efficacy with increases in hematocrit among five SGLT2i trials with available data (slope .96; P slope .07). We did not find any indication of mediation effects by SBP and uACR for SGLT2i or GLP-1RAs (slopes -.11 -.07; P slopes ≥ .05).

Conclusion: We confirm previous findings of increased CV benefits with reductions in HbA1c for GLP1-RAs. Further research is needed to investigate the potential loss of SGLT2i efficacy with greater weight loss and increase in hematocrit.

Premature ventricular complexes during continuous electrocardiographic monitoring in the intensive care unit: Occurrence rates and associated patient characteristics

AIMS AND OBJECTIVES

This study examined the occurrence rate of specific types of premature ventricular complex (PVC) alarms and whether patient demographic and/or clinical characteristics were associated with PVC occurrences.

BACKGROUND

Because PVCs can signal myocardial irritability, in-hospital electrocardiographic (ECG) monitors are typically configured to alert nurses when they occur. However, PVC alarms are common and can contribute to alarm fatigue. A better understanding of occurrences of PVCs could help guide alarm management strategies.

DESIGN

A secondary quantitative analysis from an alarm study.

METHODS

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist was followed. Seven PVC alarm types (vendor-specific) were described, and included isolated, couplet, bigeminy, trigeminy, run PVC (i.e. VT >2), R-on-T and PVCs/min. Negative binomial and hurdle regression analyses were computed to examine the association of patient demographic and clinical characteristics with each PVC type.

RESULTS

A total of 797,072 PVC alarms (45,271 monitoring hours) occurred in 446 patients, including six who had disproportionately high PVC alarm counts (40% of the total alarms). Isolated PVCs were the most frequent type (81.13%) while R-on-T were the least common (0.29%). Significant predictors associated with higher alarms rates: older age (isolated PVCs, bigeminy and couplets); male sex and presence of PVCs on the 12-lead ECG (isolated PVCs). Hyperkalaemia at ICU admission was associated with a lower R-on-T type PVCs.

CONCLUSIONS

Only a few distinct demographic and clinical characteristics were associated with the occurrence rate of PVC alarms. Further research is warranted to examine whether PVCs were associated with adverse outcomes, which could guide alarm management strategies to reduce unnecessary PVC alarms.

RELEVANCE TO CLINICAL PRACTICE

Targeted alarm strategies, such as turning off certain PVC-type alarms and evaluating alarm trends in the first 24 h of admission in select patients, might add to the current practice of alarm management.

Lifetime Cardiovascular Disease Risk by Coronary Artery Calcium Score in Individuals With and Without Diabetes: An Analysis From the Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

To assess lifetime cardiovascular disease (CVD) risk by coronary artery calcium (CAC) score in individuals with diabetes from the Multi-Ethnic Study of Atherosclerosis (MESA) and compare risk with that in individuals without diabetes.

RESEARCH DESIGN AND METHODS

We developed a microsimulation model with well, diabetes, post-CVD, and death health states using multivariable time-dependent Cox regression with age as time scale. We initially used 10-year follow-up data of 6,769 MESA participants, including coronary heart disease (CHD) (n = 272), heart failure (n = 201), stroke (n = 186), and competing death (n = 619) and assessed predictive validity at 15 years. We externally validated the model in matched National Health and Nutrition Examination Survey (NHANES) participants. Subsequently, we predicted CVD risk until age 100 years by diabetes, 10-year pooled cohort equations risk, and CAC score category (0, 1-100, or 100+).

RESULTS

The model showed good calibration and discriminative performance at 15 years, with discrimination indices 0.71-0.78 across outcomes. In the NHANES cohort, predicted 15-year mortality risk corresponded well with Kaplan-Meier risk, especially for those with diabetes: 29.6% (95% CI 24.9-34.8) vs. 32.4% (95% CI 27.2-37.2), respectively. Diabetes increased lifetime CVD risk, similar to shifting one CAC category upward (from 0 to 1-100 or from 1-100 to 100+). Patients with diabetes and CAC score of 0 had a lifetime CVD risk that overlapped with that of individuals without diabetes who were at low 10-year pooled cohort equations risk (<7.5%).

CONCLUSIONS

Patients with diabetes carry a spectrum of CVD risk. CAC scoring may improve decisions for preventive interventions for patients with diabetes by better delineating lifetime CVD risk.

Long-term Predictions of Incident Coronary Artery Calcium to 85 Years of Age for Asymptomatic Individuals With and Without Type 2 Diabetes

OBJECTIVE

To examine the utility of repeated computed tomography (CT) coronary artery calcium (CAC) testing, we assessed risks of detectable CAC and its cardiovascular consequences in individuals with and without type 2 diabetes ages 45-85 years.

RESEARCH DESIGN AND METHODS

We included 5,836 individuals (618 with type 2 diabetes, 2,972 without baseline CAC) from the Multi-Ethnic Study of Atherosclerosis. With logistic and Cox regression we evaluated the impact of type 2 diabetes, diabetes treatment duration, and other predictors on prevalent and incident CAC. We used time-dependent Cox modeling of follow-up data (median 15.9 years) for two repeat CT exams and cardiovascular events to assess the association of CAC at follow-up CT with cardiovascular events.

RESULTS

For 45 year olds with type 2 diabetes, the likelihood of CAC at baseline was 23% vs. 17% for those without. Median age at incident CAC was 52.2 vs. 62.3 years for those with and without diabetes, respectively. Each 5 years of diabetes treatment increased the odds and hazard rate of CAC by 19% (95% CI 8-33) and 22% (95% CI 6-41). Male sex, White ethnicity/race, hypertension, hypercholesterolemia, obesity, and low serum creatinine also increased CAC. CAC at follow-up CT independently increased coronary heart disease rates.

CONCLUSIONS

We estimated cumulative CAC incidence to age 85 years. Patients with type 2 diabetes develop CAC at a younger age than those without diabetes. Because incident CAC is associated with increased coronary heart disease risk, the value of periodic CAC-based risk assessment in type 2 diabetes should be evaluated.

Estimating Long-Term Health Utility Scores and Expenditures for Cardiovascular Disease From the Medical Expenditure Panel Survey

BACKGROUND

Long-term health utility scores and costs used in cost-effectiveness analyses of cardiovascular disease prevention and management can be inconsistent, outdated, or invalid for the diverse population of the United States. Our aim was to develop a user friendly, standardized, publicly available code and catalog to derive more valid long-term values for health utility and expenditures following cardiovascular disease events.

METHODS

Individual-level Short Form-12 version 2 health-related quality of life and expenditure data were obtained from the pooled 2011 to 2016 Medical Expenditure Panel Surveys. We developed code using the R programming language to estimate preference-weighted Short Form-6D utility scores from the Short Form-12 for quality-adjusted life year calculations and predict annual health care expenditures. Result predictors included cardiovascular disease diagnosis (myocardial infarction, ischemic stroke, heart failure, cardiac dysrhythmias, angina pectoris, and peripheral artery disease), sociodemographic factors, and comorbidity variables.

RESULTS

The cardiovascular disease diagnoses with the lowest utility scores were heart failure (0.635 [95% CI, 0.615-0.655]), angina pectoris (0.649 [95% CI, 0.630-0.667]), and ischemic stroke (0.649 [95% CI, 0.635-0.663]). The highest annual expenditures were for heart failure ($20 764 [95% CI, $17 500-$24 027]), angina pectoris ($18 428 [95% CI, $16 102-$20 754]), and ischemic stroke ($16 925 [95% CI, $15 672-$20 616]).

CONCLUSIONS

The developed code and catalog may improve the quality and comparability of cost-effectiveness analyses by providing standardized methods for extracting long-term health utility scores and expenditures from Medical Expenditure Panel Survey data, which are more current and representative of the US population than previous sources.

Fully Automated Echocardiogram Interpretation in Clinical Practice

BACKGROUND

Automated cardiac image interpretation has the potential to transform clinical practice in multiple ways, including enabling serial assessment of cardiac function by nonexperts in primary care and rural settings. We hypothesized that advances in computer vision could enable building a fully automated, scalable analysis pipeline for echocardiogram interpretation, including (1) view identification, (2) image segmentation, (3) quantification of structure and function, and (4) disease detection.

METHODS

Using 14 035 echocardiograms spanning a 10-year period, we trained and evaluated convolutional neural network models for multiple tasks, including automated identification of 23 viewpoints and segmentation of cardiac chambers across 5 common views. The segmentation output was used to quantify chamber volumes and left ventricular mass, determine ejection fraction, and facilitate automated determination of longitudinal strain through speckle tracking. Results were evaluated through comparison to manual segmentation and measurements from 8666 echocardiograms obtained during the routine clinical workflow. Finally, we developed models to detect 3 diseases: hypertrophic cardiomyopathy, cardiac amyloid, and pulmonary arterial hypertension.

RESULTS

Convolutional neural networks accurately identified views (eg, 96% for parasternal long axis), including flagging partially obscured cardiac chambers, and enabled the segmentation of individual cardiac chambers. The resulting cardiac structure measurements agreed with study report values (eg, median absolute deviations of 15% to 17% of observed values for left ventricular mass, left ventricular diastolic volume, and left atrial volume). In terms of function, we computed automated ejection fraction and longitudinal strain measurements (within 2 cohorts), which agreed with commercial software-derived values (for ejection fraction, median absolute deviation=9.7% of observed, N=6407 studies; for strain, median absolute deviation=7.5%, n=419, and 9.0%, n=110) and demonstrated applicability to serial monitoring of patients with breast cancer for trastuzumab cardiotoxicity. Overall, we found automated measurements to be comparable or superior to manual measurements across 11 internal consistency metrics (eg, the correlation of left atrial and ventricular volumes). Finally, we trained convolutional neural networks to detect hypertrophic cardiomyopathy, cardiac amyloidosis, and pulmonary arterial hypertension with C statistics of 0.93, 0.87, and 0.85, respectively.

CONCLUSIONS

Our pipeline lays the groundwork for using automated interpretation to support serial patient tracking and scalable analysis of millions of echocardiograms archived within healthcare systems.

An 8-week, open-label, dose-finding study of nimodipine for the treatment of progranulin insufficiency from GRN gene mutations

Introduction

Frontotemporal lobar degeneration-causing mutations in the progranulin (GRN) gene reduce progranulin protein (PGRN) levels, suggesting that restoring PGRN in mutation carriers may be therapeutic. Nimodipine, a Food and Drug Administration-approved blood-brain barrier-penetrant calcium channel blocker, increased PGRN levels in PGRN-deficient murine models. We sought to assess safety and tolerability of oral nimodipine in human GRN mutation carriers.

Methods

We performed an open-label, 8-week, dose-finding, phase 1 clinical trial in eight GRN mutation carriers to assess the safety and tolerability of nimodipine and assayed fluid and radiologic markers to investigate therapeutic endpoints.

Results

There were no serious adverse events; however, PGRN concentrations (cerebrospinal fluid and plasma) did not change significantly following treatment (percent changes of -5.2 ± 10.9% in plasma and -10.2 ± 7.8% in cerebrospinal fluid). Measurable atrophy within the left middle frontal gyrus was observed over an 8-week period.

Discussion

While well tolerated, nimodipine treatment did not alter PGRN concentrations or secondary outcomes.

Appropriate Reconciliation of Cardiovascular Medications After Elective Surgery and Postdischarge Acute Hospital and Ambulatory Visits

OBJECTIVE

To describe appropriate discharge reconciliation of cardiovascular medications and assess associations with postdischarge healthcare utilization in surgical patients.

DESIGN

Retrospective cohort study from January 2007 to December 2011.

SETTING

An academic medical center.

PATIENTS

Seven hundred and fifty-two adults undergoing elective noncardiac surgery and taking antiplatelet agents, beta-blockers, renin-angiotensin system inhibitors, or statin lipid-lowering agents before surgery.

MEASUREMENTS

Primary predictor: appropriate discharge reconciliation of preoperative cardiovascular medications (continuation without documented contraindications). Primary outcomes: acute hospital visits (emergency department visits or hospitalizations) and unplanned ambulatory visits (primary care or surgical) at 30 days after surgery.

RESULTS

Preoperative medications were appropriately reconciled in 436 (58.0%) patients. For individual medications, appropriate discharge reconciliation occurred for 156 of the 327 patients on antiplatelet agents (47.7%), 507 of the 624 patients on beta-blockers (81.3%), 259 of the 361 patients on renin-angiotensin system inhibitors (71.8%), and 302 of the 406 patients on statins (74.4%). In multivariable analyses, appropriate reconciliation of all preoperative medications was not associated with acute hospital (adjusted odds ratio [AOR], 0.94; 95% confidence interval [CI], 0.63-1.41) or unplanned ambulatory visits (AOR, 1.48; 95% CI, 0.94-2.35). Appropriate reconciliation of statin therapy was associated with lower odds of acute hospital visits (AOR, 0.47; 95% CI, 0.26-0.85). There were no other statistically significant associations between appropriate reconciliation of individual medications and either outcome.

CONCLUSIONS

Although large gaps in appropriate discharge reconciliation of chronic cardiovascular medications were common in patients undergoing elective surgery, these gaps were not consistently associated with postdischarge acute hospital or ambulatory visits.

Cost-effectiveness of the polypill versus risk assessment for prevention of cardiovascular disease

OBJECTIVE

There is an international trend towards recommending medication to prevent cardiovascular disease (CVD) in individuals at increasingly lower cardiovascular risk. We assessed the cost-effectiveness of a population approach with a polypill including a statin (simvastatin 20 mg) and three antihypertensive agents (amlodipine 2.5 mg, losartan 25 mg and hydrochlorothiazide 12.5 mg) and periodic risk assessment with different risk thresholds.

METHODS

We developed a microsimulation model for lifetime predictions of CVD events, diabetes, and death in 259 146 asymptomatic UK Biobank participants aged 40-69 years. We assessed incremental costs and quality-adjusted life-years (QALYs) for polypill scenarios with the same combination of agents and doses but differing for starting age, and periodic risk assessment with 10-year CVD risk thresholds of 10% and 20%.

RESULTS

Restrictive risk assessment, in which statins and antihypertensives were prescribed when risk exceeded 20%, was the optimal strategy gaining 123 QALYs (95% credible interval (CI) -173 to 387) per 10 000 individuals at an extra cost of £1.45 million (95% CI 0.89 to 1.94) as compared with current practice. Although less restrictive risk assessment and polypill scenarios prevented more CVD events and attained larger survival gains, these benefits were offset by the additional costs and disutility of daily medication use. Lowering the risk threshold for prescription of statins to 10% was economically unattractive, costing £40 000 per QALY gained. Starting the polypill from age 60 onwards became the most cost-effective scenario when annual drug prices were reduced below £240. All polypill scenarios would save costs at prices below £50.

CONCLUSIONS

Periodic risk assessment using lower risk thresholds is unlikely to be cost-effective. The polypill would become cost-effective if drug prices were reduced.

Comparing the cost-effectiveness of four novel risk markers for screening asymptomatic individuals to prevent cardiovascular disease (CVD) in the US population

BACKGROUND

High sensitivity CRP (hsCRP), coronary artery calcification on CT (CT calcium), carotid artery intima media thickness on ultrasound (cIMT) and ankle-brachial index (ABI) improve prediction of cardiovascular disease (CVD) risk, but the benefit of screening with these novel risk markers in the U.S. population is unclear.

METHODS AND RESULTS

A microsimulation model evaluating lifelong cost-effectiveness for individuals aged 40-85 at intermediate risk of CVD, using 2003-2004 NHANES-III (N=3736), Framingham Heart Study, U.S. Vital Statistics, meta-analyses of independent predictive effects of the four novel risk markers and treatment effects was constructed. Using both an intention-to-treat (assumes adherence <100% and incorporates disutility from taking daily medications) and an as-treated (100% adherence and no disutility) analysis, quality adjusted life years (QALYs), lifetime costs (2014 US $), and incremental cost-effectiveness ratios (ICER in $/QALY gained) of screening with hsCRP, CT coronary calcium, cIMT and ABI were established compared with current practice, full adherence to current guidelines, and ubiquitous statin therapy. In the intention-to-treat analysis in men, screening with CT calcium was cost effective ($32,900/QALY) compared with current practice. In women, screening with hsCRP was cost effective ($32,467/QALY). In the as-treated analysis, statin therapy was both more effective and less costly than all other strategies for both men and women.

CONCLUSIONS

When a substantial disutility from taking daily medication is assumed, screening men with CT coronary calcium is likely to be cost-effective whereas screening with hsCRP has value in women. The individual perceived disutility for taking daily medication should play a key role in the decision.

The new lipid guidelines: what do primary care clinicians think?

BACKGROUND

Little is known about the opinions of primary care clinicians regarding the newly released 2013 American College of Cardiology/American Heart Association (ACC/AHA) Guidelines for the Prevention of Primary and Secondary Atherosclerotic Disease. This survey was created to assess the awareness, attitudes, and practices of primary care clinicians on adoption of the new guidelines and to explore obstacles to implementation and suggestions for improving shared decision-making.

METHODS

Six hundred practicing clinicians within the San Francisco Bay Area Collaborative Research Network were invited to participate in this cross-sectional, Internet-based pilot survey of primary care clinicians. These survey data were collected in March 2014, approximately 4 months after the release of the new guidelines and 1 month after the release of the ACC/AHA risk estimator application.

RESULTS

One hundred eighty-three clinicians responded to the survey. Of those respondents, 176 (96%) were aware of the guidelines. The majority (64%) reported implementing the new guidelines with at least some of their patients, while a minority (25%) reported adopting the guidelines for many of their patients. Disagreeing with the guidelines was the main hindrance to adoption.

CONCLUSIONS

While many primary care clinicians are aware of the new guidelines, a substantial proportion has yet to implement them into their clinical practice, and obstacles remain for full adoption. Further understanding of clinicians' views, opinions, and needs is necessary to optimize the approach to lipid management and ensure integration into current practice.

The optimal imaging strategy for patients with stable chest pain: a cost-effectiveness analysis

BACKGROUND

The optimal imaging strategy for patients with stable chest pain is uncertain.

OBJECTIVE

To determine the cost-effectiveness of different imaging strategies for patients with stable chest pain.

DESIGN

Microsimulation state-transition model.

DATA SOURCES

Published literature.

TARGET POPULATION

60-year-old patients with a low to intermediate probability of coronary artery disease (CAD).

TIME HORIZON

Lifetime.

PERSPECTIVE

The United States, the United Kingdom, and the Netherlands.

INTERVENTION

Coronary computed tomography (CT) angiography, cardiac stress magnetic resonance imaging, stress single-photon emission CT, and stress echocardiography.

OUTCOME MEASURES

Lifetime costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios.

RESULTS OF BASE-CASE ANALYSIS

The strategy that maximized QALYs and was cost-effective in the United States and the Netherlands began with coronary CT angiography, continued with cardiac stress imaging if angiography found at least 50% stenosis in at least 1 coronary artery, and ended with catheter-based coronary angiography if stress imaging induced ischemia of any severity. For U.K. men, the preferred strategy was optimal medical therapy without catheter-based coronary angiography if coronary CT angiography found only moderate CAD or stress imaging induced only mild ischemia. In these strategies, stress echocardiography was consistently more effective and less expensive than other stress imaging tests. For U.K. women, the optimal strategy was stress echocardiography followed by catheter-based coronary angiography if echocardiography induced mild or moderate ischemia.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to changes in the probability of CAD and assumptions about false-positive results.

LIMITATIONS

All cardiac stress imaging tests were assumed to be available. Exercise electrocardiography was included only in a sensitivity analysis. Differences in QALYs among strategies were small.

CONCLUSION

Coronary CT angiography is a cost-effective triage test for 60-year-old patients who have nonacute chest pain and a low to intermediate probability of CAD.

PRIMARY FUNDING SOURCE

Erasmus University Medical Center.

Perioperative beta blockade in noncardiac surgery: a systematic review for the 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines

OBJECTIVE

To review the literature systematically to determine whether initiation of beta blockade within 45 days prior to noncardiac surgery reduces 30-day cardiovascular morbidity and mortality rates.

METHODS

PubMed (up to April 2013), Embase (up to April 2013), Cochrane Central Register of Controlled Trials (up to March 2013), and conference abstracts (January 2011 to April 2013) were searched for randomized controlled trials (RCTs) and cohort studies comparing perioperative beta blockade with inactive control during noncardiac surgery. Pooled relative risks (RRs) were calculated under the random-effects model. We conducted subgroup analyses to assess how the DECREASE-I (Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echocardiography), DECREASE-IV, and POISE-1 (Perioperative Ischemic Evaluation) trials influenced our conclusions.

RESULTS

We identified 17 studies, of which 16 were RCTs (12 043 participants) and 1 was a cohort study (348 participants). Aside from the DECREASE trials, all other RCTs initiated beta blockade within 1 day or less prior to surgery. Among RCTs, beta blockade decreased nonfatal myocardial infarction (MI) (RR: 0.69; 95% confidence interval [CI]: 0.58 to 0.82) but increased nonfatal stroke (RR: 1.76; 95% CI: 1.07 to 2.91), hypotension (RR: 1.47; 95% CI: 1.34 to 1.60), and bradycardia (RR: 2.61; 95% CI: 2.18 to 3.12). These findings were qualitatively unchanged after the DECREASE and POISE-1 trials were excluded. Effects on mortality rate differed significantly between the DECREASE trials and other trials. Beta blockers were associated with a trend toward reduced all-cause mortality rate in the DECREASE trials (RR: 0.42; 95% CI: 0.15 to 1.22) but with increased all-cause mortality rate in other trials (RR: 1.30; 95% CI: 1.03 to 1.64). Beta blockers reduced cardiovascular mortality rate in the DECREASE trials (RR: 0.17; 95% CI: 0.05 to 0.64) but were associated with trends toward increased cardiovascular mortality rate in other trials (RR: 1.25; 95% CI: 0.92 to 1.71). These differences were qualitatively unchanged after the POISE-1 trial was excluded.

CONCLUSIONS

Perioperative beta blockade started within 1 day or less before noncardiac surgery prevents nonfatal MI but increases risks of stroke, death, hypotension, and bradycardia. Without the controversial DECREASE studies, there are insufficient data on beta blockade started 2 or more days prior to surgery. Multicenter RCTs are needed to address this knowledge gap.

Predictive value of updating Framingham risk scores with novel risk markers in the U.S. general population

Background

According to population-based cohort studies CT coronary calcium score (CTCS), carotid intima-media thickness (cIMT), high-sensitivity C- reactive protein (CRP), and ankle-brachial index (ABI) are promising novel risk markers for improving cardiovascular risk assessment. Their impact in the U.S. general population is however uncertain. Our aim was to estimate the predictive value of four novel cardiovascular risk markers for the U.S. general population.

Methods and Findings

Risk profiles, CRP and ABI data of 3,736 asymptomatic subjects aged 40 or older from the National Health and Nutrition Examination Survey (NHANES) 2003–2004 exam were used along with predicted CTCS and cIMT values. For each subject, we calculated 10-year cardiovascular risks with and without each risk marker. Event rates adjusted for competing risks were obtained by microsimulation. We assessed the impact of updated 10-year risk scores by reclassification and C-statistics. In the study population (mean age 56±11 years, 48% male), 70% (80%) were at low (<10%), 19% (14%) at intermediate (≥10–<20%), and 11% (6%) at high (≥20%) 10-year CVD (CHD) risk. Net reclassification improvement was highest after updating 10-year CVD risk with CTCS: 0.10 (95%CI 0.02–0.19). The C-statistic for 10-year CVD risk increased from 0.82 by 0.02 (95%CI 0.01–0.03) with CTCS. Reclassification occurred most often in those at intermediate risk: with CTCS, 36% (38%) moved to low and 22% (30%) to high CVD (CHD) risk. Improvements with other novel risk markers were limited.

Conclusions

Only CTCS appeared to have significant incremental predictive value in the U.S. general population, especially in those at intermediate risk. In future research, cost-effectiveness analyses should be considered for evaluating novel cardiovascular risk assessment strategies.

Risk factors and prognosis for clot formation on cardiac device leads

BACKGROUND

Clot formation on cardiac device leads is poorly understood. We sought to determine how often clot is seen on device leads by transthoracic echo (TTE), identify risk factors, and to describe the natural history of this phenomenon.

METHODS

We reviewed 71,888 echocardiographic studies performed at the University of California, San Francisco from 2005 to 2011. We searched for cases where clot was found adhered to a device lead with no diagnosis of endocarditis. For every case, three age-matched controls with a device but no clot were selected from the echo database.

RESULTS

We found 15 cases with clot adhered to a device lead among 1,086 patients with devices who had TTE (1.4%). In univariate analysis, females had more than four times greater odds of having a clot on their device lead and patients with a history of atrial fibrillation (AF) had an eight times greater odds. Percentage mode switch was also associated with clot formation. Only AF was still associated with clot formation after multivariate analysis. Follow-up data were available for nine of 15 patients. All nine patients had intensification of their anticoagulant/antiplatelet regimen following clot discovery. Complete resolution or shrinkage of clot was observed in eight of nine patients. The one case with no change was a patient who continued taking only aspirin (higher dose) after clot discovery. None of the nine patients had embolic phenomenon.

CONCLUSION

Patients with AF are at higher risk for clot formation on device leads. After clot detection, treatment with anticoagulants usually results in resolution of the clot without embolic phenomenon.

Prehospital electrocardiographic manifestations of acute myocardial ischemia independently predict adverse hospital outcomes

BACKGROUND

Prehospital electrocardiography (PH ECG) is becoming the standard of care for patients activating Emergency Medical Services for symptoms of acute coronary syndrome (ACS). Little is known about the prognostic value of ischemia found on PH ECG.

OBJECTIVE

The purpose of this study was to determine whether manifestations of acute myocardial ischemia on PH ECG are predictive of adverse hospital outcomes.

METHODS

This study was a retrospective analysis of all PH ECGs recorded in 630 patients who called 911 for symptoms of ACS and were enrolled in a prospective clinical trial. ST-segment monitoring software was added to the PH ECG device with automatic storage and transmission of ECGs to the destination Emergency Department. Patient medical records were reviewed for adverse hospital outcomes.

RESULTS

In 630 patients who called 911 for ACS symptoms, 270 (42.9%) had PH ECG evidence of ischemia. Overall, 37% of patients with PH ECG ischemia had adverse hospital outcomes compared with 27% of patients without PH ECG ischemia (p < 0.05). Those with PH ECG ischemia were 1.55 times more likely to have adverse hospital outcomes than those without PH ECG ischemia (95% CI 1.09-2.21; p < 0.05), after controlling for other predictors of adverse hospital outcomes (i.e., age, sex, and medical history).

CONCLUSIONS

Evidence of ischemia on PH ECG is an independent predictor of adverse hospital outcomes. ST-segment monitoring in the prehospital setting can identify high-risk patients with symptoms of ACS and provide important prognostic information at presentation to the Emergency Department.

Coronary computed tomography versus exercise testing in patients with stable chest pain: comparative effectiveness and costs

BACKGROUND

To determine the comparative effectiveness and costs of a CT-strategy and a stress-electrocardiography-based strategy (standard-of-care; SOC-strategy) for diagnosing coronary artery disease (CAD).

METHODS

A decision analysis was performed based on a well-documented prospective cohort of 471 outpatients with stable chest pain with follow-up combined with best-available evidence from the literature. Outcomes were correct classification of patients as CAD- (no obstructive CAD), CAD+ (obstructive CAD without revascularization) and indication for Revascularization (using a combination reference standard), diagnostic costs, lifetime health care costs, and quality-adjusted life years (QALY). Parameter uncertainty was analyzed using probabilistic sensitivity analysis.

RESULTS

For men (and women), diagnostic cost savings were €245 (€252) for the CT-strategy as compared to the SOC-strategy. The CT-strategy classified 82% (88%) of simulated men (women) in the appropriate disease category, whereas 83% (85%) were correctly classified by the SOC-strategy. The long-term cost-effectiveness analysis showed that the SOC-strategy was dominated by the CT-strategy, which was less expensive (-€229 in men, -€444 in women) and more effective (+0.002 QALY in men, +0.005 in women). The CT-strategy was cost-saving (-€231) but also less effective compared to SOC (-0.003 QALY) in men with a pre-test probability of ≥ 70%. The CT-strategy was cost-effective in 100% of simulations, except for men with a pre-test probability ≥ 70% in which case it was 59%.

CONCLUSIONS

The results suggest that a CT-based strategy is less expensive and equally effective compared to SOC in all women and in men with a pre-test probability <70%.

Caregiving for patients with heart failure: impact on patients' families

BACKGROUND

Factors that affect the impact of caregiving on patients' family members who provide care to patients with heart failure have not been adequately addressed. In addition, social support and positive aspects of caregiving have received little attention.

OBJECTIVE

To identify factors associated with the impact of caregiving.

METHODS

Self-report data were collected from 76 dyads of patients with heart failure and their family caregivers. Clinical data were obtained from medical records.

RESULTS

A sense of less family support for caregiving was associated with a higher New York Heart Association class of heart failure, being a nonspousal caregiver, lower caregivers' perceived control, and less social support. More disruption of caregivers' schedules was associated with higher class of heart failure, more care tasks, and less social support. Greater impact of caregiving on caregivers' health was related to more recent patient hospitalization, lower caregivers' perceived control, and less social support. Nonwhite caregivers and caregivers whose family member had fewer emergency department visits felt more positive about caregiving than did other caregivers. Social support had a moderating effect on the relationship between patients' comorbid conditions and positive aspects of caregiving.

CONCLUSIONS

Caregiving has both positive and negative effects on family caregivers of patients with heart failure. The findings suggest the need for interventions to increase caregivers' sense of control and social support. Family caregivers may need additional support immediately after patient hospitalizations to minimize the negative impact of caregiving.

The new universal definition of myocardial infarction criteria improve electrocardiographic diagnosis of acute coronary syndrome

INTRODUCTION/METHODS

To assess whether revised electrocardiographic (ECG) criteria improve emergency department identification of patients with acute myocardial infarction (MI) or unstable angina (UA) and predict outcome, we studied 120 patients with a nondiagnostic initial ECG by prior criteria. Electrocardiograms were read in a blinded fashion months apart with standard and then revised criteria, and analyzed by χ(2) and logistic regression analysis.

RESULTS

In 12 subjects (10%), the initial ECG was now interpreted as diagnostic of ischemia. Eleven (92%) had an MI, 1 had UA (8%), and none had a noncardiac diagnosis. Ischemic ECG changes were strongly associated with MI or UA (P = .003). At 1-year follow-up, ECG changes diagnostic of ischemia were associated with a trend toward higher mortality (25% vs 7%, P = .07), but after adjustment for clinical factors, ECG changes were not an independent predictor of 1-year mortality.

CONCLUSIONS

Revision of the ECG criteria for ischemia was associated with enhanced diagnostic performance and identified a subset of patients at higher risk.

Atrial fibrillation and quality of life after pacemaker implantation for sick sinus syndrome: data from the Mode Selection Trial (MOST)

BACKGROUND

In the Mode Selection Trial (MOST) of 2,010 patients with sinus node dysfunction, dual-chamber-paced patients had less atrial fibrillation (AF) and heart failure and had slightly improved health-related quality of life (QOL) compared with rate modulated right ventricular-paced patients. Our objective was to assess the impact of AF on QOL within MOST.

METHODS

We analyzed serial QOL measures (Short Form-36, Specific Activity Scale, time trade-off) in 3 groups: (1) those without AF; (2) those with paroxysmal AF (PAF), but not chronic AF (CAF); and (3) those with CAF. We carried forward the last known QOL before crossover for all subsequent time points in patients randomized to rate modulated right ventricular pacing who crossed over to dual-chamber pacing for severe pacemaker syndrome.

RESULTS

Three hundred seventeen patients (15.8%) had AF in the year after implantation, 206 patients within 3 months (191 PAF, 15 CAF), and another 159 (124 PAF, 35 CAF) between 3 and 12 months. There were no significant differences among groups in individual Short Form-36 subscales or time trade-off scores at 12 months as compared with baseline or 3 months. Cardiovascular health status was better at 12 months as compared with baseline or 3 months in those without AF.

CONCLUSIONS

Atrial fibrillation after pacemaker implantation in elderly patients with sick sinus syndrome was not a major determinant of QOL. However, there was a trend toward better cardiovascular functional status in patients without AF.

Estimated body surface potential maps in emergency department patients with unrecognized transient myocardial ischemia

BACKGROUND

We report on 5 patients who presented to the emergency department (ED) with chest pain, had negative serum troponin levels, and were discharged with a presumed noncardiac diagnosis. Thereafter, retrospective analysis of Holter monitoring data recorded for a clinical trial revealed ST events indicative of transient myocardial ischemia that was unrecognized clinically.

STUDY AIM

The purpose of this analysis was to determine whether initial body surface potential maps estimated from optimal ischemia electrode sites estimated body surface potential map (EBSPM) showed signs of ischemia in the missed ischemia group that could have prevented misdiagnosis.

METHODS

This is a secondary analysis of data from a prospective clinical trial in which patients were attached to 2 Holter monitor devices for simultaneous recordings. One Holter device recorded a standard Mason-Likar 12-lead electrocardiogram (ECG) and the other recorded a 10-electrode lead set considered optimal for ischemia detection. A body surface potential map was then estimated from the optimal lead set.

RESULTS

At 1 year, 2 of the 5 patients with missed ischemia died and a third had an acute myocardial infarction (MI) (40% mortality, 60% death/nonfatal MI). In comparison, 1-year mortality was 5.7% in 159 similar patients treated for unstable angina at the same institution over the same period (P = .037). The initial standard ECG showed no abnormalities in 3 patients and showed left ventricular hypertrophy in 1. The fifth patient with a history of recent MI had slight ST elevation in leads III and aVF and Q waves that were considered indicative of recent (not acute) MI. EBSPM data recorded at the time of ED presentation matched the standard ECG (normal in 3, left ventricular hypertrophy or inconclusive in 2). During transient ischemia, all 5 EBSPMs showed areas of ischemia overlapping with standard electrode sites.

CONCLUSION

Patients evaluated in the ED for chest pain are at high risk for death or nonfatal MI if they have ischemic events with continuous ST-segment monitoring that are unrecognized clinically. In this small cohort with unrecognized ischemia, the initial body surface potential maps estimated from optimal ischemia electrode sites did not improve on 12-lead ST-segment monitoring to identify this high-risk group.

Dynamic tracking of ischemia in the surface electrocardiogram

BACKGROUND

Accurate detection of the earliest signs of ischemia on the surface electrocardiogram (ECG) is essential for timely diagnosis and management of potentially life-threatening ischemic events. Yet, accuracy of ischemia analysis in ECG monitors remains suboptimal because of a number of confounding factors, including changes in body position and other artifacts. Hence, the goals of this study were (1) to examine the duration and time course of ischemic events and (2) to compare ECG changes caused by "true" ischemic events with those caused by changes in body position. Continuous, 12-lead Holter ECGs obtained from patients who presented to the emergency department with chest pain and enrolled in the Ischemia Monitoring and Mapping in the Emergency Department in Appropriate Triage and Evaluation of Acute Ischemic Myocardium study were analyzed. Holter recordings were initiated within the first 40 minutes after patients' arrival to the emergency department. Here we present preliminary results.

METHODS

Twelve patients (age, 59 +/- 16 years; 5 women, 2 with a final diagnosis of non-ST-segment elevation myocardial infarction, 4 with unstable angina, and 6 with other cardiovascular diseases), in whom ischemic ST deviations were identified on Holter data, underwent 4 consecutive, 2-minute recordings in the following body positions: (1) supine, (2) on the left side, (3) on the right side, and (4) sitting (or standing) upright. After baseline correction, beat-to-beat changes in QRS and ST-T segments were examined in all 8 channels and the root-mean-square curve by using an adaptive algorithm that computes the slope, amplitude, duration, area, and the Karhunen-Loève-derived representation of the corresponding segment. To prevent possible biases toward patients with more frequent ischemic events, a single index event was chosen for analysis in each patient. There were 3 ST-elevation events and 9 ST-depression events; these events reached the maximum ST deviation 11 +/- 8 hours (mean +/- SD) after the beginning of the recording.

RESULTS AND CONCLUSIONS

In most patients with transient myocardial ischemia, the microvolt-level, subthreshold deviation of the ST segment developed gradually, over 15 to 20 minutes, until it reached the maximum, superthreshold level. Despite the different ischemia localizations, the root-mean-square curve allowed accurate detection of significant changes in the ST segment in the studied group (Friedman analysis of variance for repeated measurements over a 1-hour interval). Changes in body position could be identified by tracking dynamics of the QRS pattern/axis. Adaptive algorithms for tracking of the ST dynamics with simultaneous tracking of the patterns of QRS complexes to discriminate the true and "false"-positive events are presented and discussed.

Remote second-hand tobacco exposure in flight attendants is associated with systemic but not pulmonary hypertension

BACKGROUND

Second-hand tobacco smoke has been associated with cardiopulmonary dysfunction. We sought to examine the residual effects of remote second-hand smoke exposure on resting and exercise cardiopulmonary hemodynamics. We hypothesized that remote secondhand smoke exposure results in persistent cardiopulmonary hemodynamic abnormalities.

METHODS

Participants were non-smoking flight attendants who worked in airline cabins prior to the in-flight tobacco ban. Participants underwent clinical evaluations and completed smoke exposure questionnaires. We used Doppler echocardiography to measure pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR) at rest and during supine bicycle ergometer exercise, using the validated formula TRV/VTIRVOT x 10 + 0.16, where VTIRVOT is the velocity time integral at the right ventricular outflow tract and TRV is the tricuspid regurgitation velocity. The group was divided into quartiles according to the degree of smoke exposure. Analysis of variance was used to determine the differences in hemodynamic outcomes.

RESULTS

Seventy-nine flight attendants were included in our analysis. Baseline characteristics among participants in each quartile of smoke exposure were similar except for history of systemic hypertension, which was more prevalent in the highest quartile. Peak exercise PASP rose to the same degree in all test groups (mean PASP 44 mm Hg, p = 0.25), and PVR increased by approximately 27% in all quartiles. There was no significant difference in pulmonary artery systolic pressure or pulmonary vascular resistance among quartiles of smoke exposure.

CONCLUSIONS

We found that remote heavy second-hand smoke exposure from in-flight tobacco is associated with systemic hypertension but does not have demonstrable pulmonary hemodynamic consequences.

Stress echocardiography, stress single-photon-emission computed tomography and electron beam computed tomography for the assessment of coronary artery disease: a meta-analysis of diagnostic performance

BACKGROUND

Many studies have been published on the diagnostic performance of noninvasive tests for the assessment of coronary artery disease. The objective of the present study was to compare the published literature on the diagnostic performance of stress echocardiography, stress single-photon-emission computed tomography (SPECT), and electron beam computed tomography (EBCT).

METHODS

Meta-analytic studies on the diagnostic performance of imaging tests for coronary artery disease were searched in the Cochrane Library, PubMed, and bibliographies of selected articles. Sensitivities, specificities, and diagnostic odds ratios of the source studies were calculated per modality. Taking into account differences between studies, a random effects summary receiver operating characteristic analysis was performed.

RESULTS

We analyzed the data of 351 patient series, which were reported in 11 meta-analyses. The sensitivity of EBCT was significantly higher than that of stress SPECT, which had a significantly higher sensitivity than stress echocardiography (respectively, 93.1% [95% confidence interval, 90.7-95.6], 88.1 [95% confidence interval, 86.6-89.6], and 79.1% [95% confidence interval, 77.6-80.5]). The specificity of stress echocardiography was significantly higher than that of stress SPECT, which had a significantly higher specificity than EBCT (respectively, 87.1% [95% confidence interval, 85.7-88.5], 73.0% [95% confidence interval, 69.1-76.9], and 54.5% [95% confidence interval, 45.3-63.8]). The diagnostic odds ratios did not differ significantly between the 3 modalities, which resulted in one underlying summary receiver operating characteristic curve.

CONCLUSIONS

This study suggests that there are no significant differences in the overall diagnostic performance between stress echocardiography, stress SPECT, and EBCT for the diagnosis of coronary artery disease. However, differences exist in sensitivity and specificity estimates, which may make each modality useful in different settings.

ACC/AHA 2006 guideline update on perioperative cardiovascular evaluation for noncardiac surgery: focused update on perioperative beta-blocker therapy--a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Update the 2002 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery)

The American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Practice Guidelines makes every effort to avoid any actual, potential, or perceived conflict of interest that might arise as a result of an industry relationship or personal interest of the writing committee. Specifically, all members of the writing committee, as well as peer reviewers of the document, were asked to provide disclosure statements of all such relationships that might be perceived as real or potential conflicts of interest. These statements are reviewed by the parent task force, reported orally to all members of the writing committee at each meeting, and updated and reviewed by the writing committee as changes occur. Please see Appendix 1 for author relationships with industry and Appendix 2 for peer reviewer relationships with industry. These guidelines attempt to define practices that meet the needs of most patients in most circumstances. These guideline recommendations reflect a consensus of expert opinion after a thorough review of the available, current scientific evidence and are intended to improve patient care. If these guidelines are used as the basis for regulatory/payer decisions, the ultimate goal is quality of care and serving the patient's best interests. The ultimate judgment regarding care of a particular patient must be made by the healthcare provider and patient in light of all the circumstances presented by that patient.

The Prognostic Value of Normal Exercise Myocardial Perfusion Imaging and Exercise Echocardiography

OBJECTIVES

The purpose of this work was to determine the prognostic value of normal exercise myocardial perfusion imaging (MPI) tests and exercise echocardiography tests, and to determine the prognostic value of these imaging modalities in women and men.

BACKGROUND

Exercise MPI and exercise echocardiography provide prognostic information that is useful in the risk stratification of patients with suspected coronary artery disease (CAD).

METHODS

We searched the PubMed, Cochrane, and DARE databases between January 1990 and May 2005, and reviewed bibliographies of articles obtained. We included prospective cohort studies of subjects who underwent exercise MPI or exercise echocardiography for known or suspected CAD, and provided data on primary outcomes of myocardial infarction (MI) and cardiac death with at least 3 months of follow-up. Secondary outcomes (unstable angina, revascularization procedures) were abstracted if provided. Studies performed exclusively in patients with CAD were excluded.

RESULTS

The negative predictive value (NPV) for MI and cardiac death was 98.8% (95% confidence interval [CI] 98.5 to 99.0) over 36 months of follow-up for MPI, and 98.4% (95% CI 97.9 to 98.9) over 33 months for echocardiography. The corresponding annualized event rates were 0.45% per year for MPI and 0.54% per year for echocardiography. In subgroup analyses, annualized event rates were <1% for each MPI isotope, and were similar for women and men. For secondary events, MPI and echocardiography had annualized event rates of 1.25% and 0.95%, respectively.

CONCLUSIONS

Both exercise MPI and exercise echocardiography have high NPVs for primary and secondary cardiac events. The prognostic utility of both modalities is similar for both men and women.

Pacemaker implantation and quality of life in the Mode Selection Trial (MOST)

BACKGROUND

Dual-chamber pacemakers restore AV synchrony compared with ventricular pacemakers, but the effects on health-related quality of life (QOL) are uncertain.

OBJECTIVES

The purpose of this study was to assess the effect of pacemaker implantation, clinical factors, and pacing mode on QOL.

METHODS

The Mode Selection Trial (MOST) randomized 2,010 patients with sinus node dysfunction to rate-modulated right ventricular (VVIR) or dual-chamber (DDDR) pacing. A longitudinal analysis of serial QOL measures (Short Form-36 [SF-36], Specific Activity Scale, and time trade-off utility) was performed. In patients who crossed over from VVIR to DDDR because of severe pacemaker syndrome, the last known QOL prior to crossover was carried forward.

RESULTS

Pacemaker implantation resulted in substantial improvement in almost all QOL measures. Subjects 75 years or older experienced significantly less improvement in functional status and physical component summary scores than did younger subjects. In longitudinal analyses of the effect of pacing mode on QOL, significant improvement in three SF-36 subscales was observed with DDDR pacing compared with VVIR pacing: role physical [62.8 points (95% confidence interval [CI] 60.2, 65.5) vs 56.4 (95% CI 53.7, 59.1)], role emotional [85.0 (95% CI 82.9, 87.0) vs 81.9 (95% CI 79.9, 84.0)], and vitality [51.8 (95% CI 50.3, 53.3) vs 49.3 (95% CI 47.8, 50.7)], but not in other SF-36 subscales, the Specific Activity Scale, or utilities. The gains in QOL were larger than the declines associated with 1 year of aging but smaller than those associated with heart failure.

CONCLUSION

Pacemaker implantation improved health-related QOL. The mode selected was associated with much smaller, but significant, improvements in several domains, particularly role physical function.