Using stress testing to guide primary prevention of coronary heart disease among intermediate-risk patients: a cost-effectiveness analysis

Left Ventricular Myocardial and Cavity Velocity Disturbances Are Powerful Predictors of Significant Coronary Artery Stenosis

Background and Aim: Dobutamine stress echocardiography (DSE) is a well-established noninvasive investigation for significant coronary artery disease (CAD). The aim of this study was to evaluate the accuracy of cardiac Doppler parameters in predicting CAD. Methods: We prospectively studied 103 consecutive patients with suspected CAD based on typical symptoms; 59 proved to have CAD, and 44 patients proved to have no-CAD (n = 44). All patients underwent a complete stress Doppler echocardiographic examination. Total isovolumic time (T-IVT) as a marker of cavity dyssynchrony and wall motion score index (WMSI) were also calculated. Results: At peak dobutamine stress, the compromised LV longitudinal excursion (MAPSE), systolic septal and lateral velocities (s’), and diastolic indices were more pronounced in the CAD patients compared with those without CAD, but LV dimension did not differ between groups (p > 0.05). The WMSI was higher and t-IVT more prolonged in patients with CAD (p < 0.01 for both). Similarly, the changes were more pronounced in patients with significant CAD compared with insignificant CAD. On multivariate model, Δ mean s’, OR 2.016 (1.610 to 3.190; p < 0.001), Δ E velocity OR 2.502 (1.179 to 1.108; p < 0.001), Δ t-IVT 2.206 (1.180 to 2.780; p < 0.001) and Δ WMSI OR 1.911 (1.401 to 3.001; p = 0.001) were the most powerful independent predictors of the presence of CAD, particularly when significant (>75%). Δ mean s’ < 5.0 was 85% sensitive, 89% specific with AUC 0.92. Respective values for Δ E velocity <6.0 cm/s were 82%, 90% and 0.91; for Δ t-IVT > 4.5, 78%, 77% and 0.81 and for Δ FT ≥ 150 ms, 76%, 78% and 0.84 in predicating significant CAD. WMSI ≥ 0.7 was 75% sensitive, 77% specific with AUC of 0.81 in predicting significant CAD. The accuracy of DSE was higher in significant CAD compared to insignificant CAD (80% vs. 74%; p = 0.03). Conclusions: Compromised LV longitudinal systolic function, lower delta E wave, prolonged t-IVT, and increased WMSI were the most powerful independent predictors of the presence and significance of CAD. These finding strengthen the role of comprehensive DSE analysis in diagnosing ischemic disturbances secondary to significant CAD.

Innovative Approaches to Assess Intermediate Cardiovascular Risk Subjects: A Review From Clinical to Metabolomics Strategies

Current risk stratification strategies for coronary artery disease (CAD) have low predictive value in asymptomatic subjects classified as intermediate cardiovascular risk. This is relevant because not all coronary events occur in individuals with traditional multiple risk factors. Most importantly, the first manifestation of the disease may be either sudden cardiac death or acute coronary syndrome, after rupture and thrombosis of an unstable non-obstructive atherosclerotic plaque, which was previously silent. The inaccurate stratification using the current models may ultimately subject the individual to excessive or insufficient preventive therapies. A breakthrough in the comprehension of the molecular mechanisms governing the atherosclerosis pathology has driven many researches toward the necessity for a better risk stratification. In this Review, we discuss how metabolomics screening integrated with traditional risk assessments becomes a powerful approach to improve non-invasive CAD subclinical diagnostics. In addition, this Review highlights the findings of metabolomics studies performed by two relevant analytical platforms in current use-mass spectrometry (MS) hyphenated to separation techniques and nuclear magnetic resonance spectroscopy (NMR) -and evaluates critically the challenges for further clinical implementation of metabolomics data. We also discuss the modern understanding of the pathophysiology of atherosclerosis and the limitations of traditional analytical methods. Our aim is to show how discriminant metabolites originated from metabolomics approaches may become promising candidate molecules to aid intermediate risk patient stratification for cardiovascular events and how these tools could successfully meet the demands to translate cardiovascular metabolic biomarkers into clinical settings.

Cost-effectiveness of myocardial perfusion SPECT and stress test according to coronary revascularization therapy, cardiac events and total mortality: Register of 8,496 patients

OBJECTIVE

The aim was to analyze the cost-effectiveness ratio (CER) of stress electrocardiogram (ES) and stress myocardial perfusion imaging (SPECT-MPI) according to coronary revascularization (CR) therapy, cardiac events (CE) and total mortality (TM).

MATERIAL AND METHODS

A total of 8,496 consecutive patients who underwent SPECT-MPI were followed-up (mean 5.3±3.5years). Cost-effectiveness for coronary bypass (CABG) or percutaneous CR (PCR) (45.6%/54.4%) according to combined electrocardiographic ischemia and scintigraphic ischemia were evaluated. Effectiveness was evaluated as TM, CE, life-year saved observed (LYSO) and CE-LYSO; costs analyses were conducted from the perspective of the health care payer. A sensitivity analysis was performed considering current CABG/PCR ratios (12%/88%).

RESULTS

When electrocardiogram and SPECT approaches are combined, the cost-effectiveness values for CABG ranged between 112,589€ (electrocardiographic and scintigraphic ischemia) and 2,814,715€ (without ischemia)/event avoided, 38,664 and 2,221,559€/LYSO; for PCR ranged between 18,824€ (electrocardiographic and scintigraphic ischemia) and 46,377€ (without ischemia)/event avoided, 6,464 and 36,604€/LYSO. To CE: the cost-effectiveness values of the CABG and CPR in presence of electrocardiographic and scintigraphic ischemia were 269,904€/CE-avoided and 24,428€/CE-avoided, respectively; and the €/LYSO of the CABG and PCR were 152,488 and 13,801, respectively. The RCE was maintained for the current proportion of revascularized patients (12%/88%).

CONCLUSIONS

Combined ES and SPECT-MPI results, allows differentiation between patient groups, where the PCR and CABG are more cost-effective in different economic frameworks. The major CER in relation to CR, CE and TM occurs in patients with electrocardiographic and scintigraphic ischemia. PCR is more cost-effective than CABG.

Statin-associated muscle symptoms: position paper from the Luso-Latin American Consortium

In the last two decades, statin therapy has proved to be the most potent isolated therapy for attenuation of cardiovascular risk. Its frequent use has been seen as one of the most important elements for the reduction of cardiovascular mortality in developed countries. However, the recurrent incidence of muscle symptoms in statin users raised the possibility of causal association, leading to a disease entity known as statin associated muscle symptoms (SAMS). Mechanistic studies and clinical trials, specifically designed for the study of SAMS have allowed a deeper understanding of the natural history and accurate incidence. This set of information becomes essential to avoid an unnecessary risk of severe forms of SAMS. At the same time, this concrete understanding of SAMS prevents overdiagnosis and an inadequate suspension of one of the most powerful prevention strategies of our times. In this context, the Luso-Latin American Consortium gathered all available information on the subject and presents them in detail in this document as the basis for the identification and management of SAMS.

Impact of Stress Testing for Coronary Artery Disease Screening in Asymptomatic Patients With Diabetes Mellitus: A Community-Based Study in Olmsted County, Minnesota

OBJECTIVE

To evaluate the impact of screening stress testing for coronary artery disease in asymptomatic patients with diabetes in a community-based population.

PATIENTS AND METHODS

This observational study included 3146 patients from Olmsted County, Minnesota, with no history of coronary artery disease or cardiac symptoms in whom diabetes was newly diagnosed from January 1, 1992, through December 31, 2008. With combined all-cause mortality and myocardial infarction as the primary outcome, weighted Cox proportional hazards regression was performed with screening stress testing within 2 years of diabetes diagnosis as the time-dependent covariate. For descriptive analysis, participants were classified by their clinical experience during the first 2 years postdiagnosis as screened (asymptomatic, underwent stress test), unscreened (asymptomatic, no stress test), or symptomatic (experienced symptoms or event).

RESULTS

Among the screened and unscreened participants, 54% (1358 of 2538) were men; the mean (SD) age at diabetes diagnosis was 55 years (13.8 years), and 97% (2442 of 2520) had type 2 diabetes. In event-free survival analysis, 292 patients comprised the screened cohort and 2246 patients comprised the unscreened cohort. Death or myocardial infarction occurred in 454 patients (32 patients in the screened cohort and 422 in the unscreened cohort [5-year rate, 1.9% and 5.3%, respectively]) during median (interquartile range) follow-up of 9.1 years (5.3-12.5 years). Screening stress testing was associated with improved event-free survival (hazard ratio, 0.61; P=.004), independent of cardiac risk factors. However, while stress test results were abnormal in 47 of the 292 screened patients (16%), only 6 (2%) underwent coronary revascularization.

CONCLUSION

Although screening cardiac stress testing in asymptomatic patients with diabetes in this community-based population was associated with improvement in long-term event-free survival, this result does not appear to occur by coronary revascularization alone.

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.

Strategies for Primary Prevention of Coronary Heart Disease Based on Risk Stratification by the ACC/AHA Lipid Guidelines, ATP III Guidelines, Coronary Calcium Scoring, and C-Reactive Protein, and a Global Treat-All Strategy: A Comparative--Effectiveness Modeling Study

Background

Several approaches have been proposed for risk-stratification and primary prevention of coronary heart disease (CHD), but their comparative and cost-effectiveness is unknown.

Methods

We constructed a state-transition microsimulation model to compare multiple approaches to the primary prevention of CHD in a simulated cohort of men aged 45–75 and women 55–75. Risk-stratification strategies included the 2013 American College of Cardiology/American Heart Association (ACC/AHA) guidelines on the treatment of blood cholesterol, the Adult Treatment Panel (ATP) III guidelines, and approaches based on coronary artery calcium (CAC) scoring and C-reactive protein (CRP). Additionally we assessed a treat-all strategy in which all individuals were prescribed either moderate-dose or high-dose statins and all males received low-dose aspirin. Outcome measures included CHD events, costs, medication-related side effects, radiation-attributable cancers, and quality-adjusted-life-years (QALYs) over a 30-year timeframe.

Results

Treat-all with high-dose statins dominated all other strategies for both men and women, gaining 15.7 million QALYs, preventing 7.3 million myocardial infarctions, and saving over $238 billion, compared to the status quo, far outweighing its associated adverse events including bleeding, hepatitis, myopathy, and new-onset diabetes. ACC/AHA guidelines were more cost-effective than ATP III guidelines for both men and women despite placing 8.7 million more people on statins. For women at low CHD risk, treat-all with high-dose statins was more likely to cause a statin-related adverse event than to prevent a CHD event.

Conclusions

Despite leading to a greater proportion of the population placed on statin therapy, the ACC/AHA guidelines are more cost-effective than ATP III. Even so, at generic prices, treating all men and women with statins and all men with low-dose aspirin appears to be more cost-effective than all risk-stratification approaches for the primary prevention of CHD. Especially for low-CHD risk women, decisions on the appropriate primary prevention strategy should be based on shared decision making between patients and healthcare providers.

Cardiac screening with electrocardiography, stress echocardiography, or myocardial perfusion imaging: advice for high-value care from the American College of Physicians

BACKGROUND

Cardiac screening in adults with resting or stress electrocardiography, stress echocardiography, or myocardial perfusion imaging can reveal findings associated with increased risk for coronary heart disease events, but inappropriate cardiac testing of low-risk adults has been identified as an important area of overuse by several professional societies.

METHODS

Narrative review based on published systematic reviews; guidelines; and articles on the yield, benefits, and harms of cardiac screening in low-risk adults.

RESULTS

Cardiac screening has not been shown to improve patient outcomes. It is also associated with potential harms due to false-positive results because they can lead to subsequent, potentially unnecessary tests and procedures. Cardiac screening is likely to be particularly inefficient in adults at low risk for coronary heart disease given the low prevalence and predictive values of testing in this population and the low likelihood that positive findings will affect treatment decisions. In this patient population, clinicians should focus on strategies for mitigating cardiovascular risk by treating modifiable risk factors (such as smoking, diabetes, hypertension, hyperlipidemia, and overweight) and encouraging healthy levels of exercise.

HIGH-VALUE CARE ADVICE

Clinicians should not screen for cardiac disease in asymptomatic, low-risk adults with resting or stress electrocardiography, stress echocardiography, or stress myocardial perfusion imaging.

Statins and aspirin for chemoprevention in Barrett's esophagus: results of a cost-effectiveness analysis

Data suggest that aspirin, statins, or a combination of the two drugs may lower the progression of Barrett's esophagus to esophageal adenocarcinoma. However, aspirin is associated with potential complications such as gastrointestinal bleeding and hemorrhagic stroke, and statins are associated with myopathy. We developed a simulation disease model to study the effectiveness and cost effectiveness of aspirin and statin chemoprevention against esophageal adenocarcinoma. A decision analytic Markov model was constructed to compare four strategies for Barrett's esophagus management; all regimens included standard endoscopic surveillance regimens: (i) endoscopic surveillance alone, (ii) aspirin therapy, (iii) statin therapy, and (iv) combination therapy of aspirin and statin. Endpoints evaluated were life expectancy, quality-adjusted life years (QALY), costs, and incremental cost-effectiveness ratios (ICER). Sensitivity analysis was performed to determine the impact of model input uncertainty on results. Assuming an annual progression rate of 0.33% per year from Barrett's esophagus to esophageal adenocarcinoma, aspirin therapy was more effective and cost less than (dominated) endoscopic surveillance alone. When combination therapy was compared with aspirin therapy, the ICER was $158,000/QALY, which was above our willingness-to-pay threshold of $100,000/QALY. Statin therapy was dominated by combination therapy. When higher annual cancer progression rates were assumed in the model (0.5% per year), combination therapy was cost-effective compared with aspirin therapy, producing an ICER of $96,000/QALY. In conclusion, aspirin chemoprevention was both more effective and cost less than endoscopic surveillance alone. Combination therapy using both aspirin and statin is expensive but could be cost-effective in patients at higher risk of progression to esophageal adenocarcinoma.

The statin-iron nexus: anti-inflammatory intervention for arterial disease prevention

OBJECTIVES

We postulated the existence of a statin-iron nexus by which statins improve cardiovascular disease outcomes at least partially by countering proinflammatory effects of excess iron stores.

METHODS

Using data from a clinical trial of iron (ferritin) reduction in advanced peripheral arterial disease, the Iron and Atherosclerosis Study, we compared effects of ferritin levels versus high-density lipoprotein to low-density lipoprotein ratios (both were randomization variables) on clinical outcomes in participants receiving and not receiving statins.

RESULTS

Statins increased high-density lipoprotein to low-density lipoprotein ratios and reduced ferritin levels by noninteracting mechanisms. Improved clinical outcomes were associated with lower ferritin levels but not with improved lipid status.

CONCLUSIONS

There are commonalities between the clinical benefits of statins and the maintenance of physiologic iron levels. Iron reduction may be a safe and low-cost alternative to statins.

Exergaming in Youth: Effects on Physical and Cognitive Health

Exergaming (a portmanteau of "exercise" and "gaming") is a relatively new genre of interactive video gaming that stimulates an active, whole-body gaming experience. Exergaming could have a significant positive impact on youth as across the globe youth are living more sedentary lifestyles. Exergaming has the potential to thwart this trend by engaging youth in physical activity (PA). Exergaming is not only physically-engaging but is also cognitively-engaging, and this combination of physical and cognitive engagement may translate into improved cognitive function in youth. The purpose of this review article is to examine the state-of-the-art in exergaming research to address whether exergames are a viable tool to promote PA in youth and benefit cognitive functioning among youth. The research addressing these questions is still quite nascent; therefore, only tentative conclusions can be drawn. However, this review points out promising lines of research and makes suggestions for future research to obtain more firm conclusions.

Most Important Papers in Health Costs, Cost-Effectiveness, and Resource Utilization

The following are highlights from the new series, Circulation: Cardiovascular Quality and Outcomes Topic Review . This series will summarize the most important manuscripts (as selected by the Editor) that have published in the Circulation portfolio. The objective of this new series is to provide our readership with a timely, comprehensive selection of important papers that are relevant to the quality and outcomes, and general cardiology audience. The studies included in this article represent the most significant research in the area of health costs, cost-effectiveness, and resource utilization.