Health Services Research & Development

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Spotlight: World Heart Day

September 2015


September 29 is World Heart Day and should serve as a reminder that heart disease is the number one killer of both men and women in the United States.1 Heart disease can describe various conditions that affect the heart, including coronary artery disease, heart rhythm problems (i.e., arrhythmias), and congenital heart defects. Coronary heart disease is the most common type of heart disease, killing more than 370,000 people each year, while about 735,000 Americans will suffer a heart attack each year. In addition, more than 500,000 VA patients have a diagnosis of ischemic heart disease (IHD) - a leading cause of mortality and hospitalization for Veterans.2

The major warning signs for heart attacks can vary by gender, and can include:

  • Chest pain or discomfort;
  • Upper body pain or discomfort in the arms, back, neck, jaw, or upper stomach;
  • Shortness of breath; and
  • Nausea, lightheadedness, or cold sweats.

Key risk factors for heart disease include:

  • Diabetes,
  • Being overweight or obese,
  • Poor diet,
  • Physical inactivity, and
  • Excessive alcohol use. 1

HSR&D Research on Heart Disease

Following are descriptions of just a few select studies that HSR&D and QUERI investigators conduct on heart disease.

Veterans with Non-Obstructive CAD at Significantly Greater Risk of MI and Mortality

Non-obstructive coronary artery disease (CAD) is atherosclerotic plaque that would not be expected to obstruct blood flow or result in symptoms of angina, so its presence has been characterized as "insignificant" or "no significant CAD" in the medical literature. However, this perception may be incorrect, as prior studies have noted that the majority of plaque ruptures and resultant myocardial infarctions (MIs) arise from non-obstructive plaques. This retrospective study compared the incidence of MI and mortality between patients with non-obstructive CAD, obstructive CAD, and no apparent CAD in a national cohort of Veterans receiving VA care. Using VA data, investigators identified all Veterans undergoing elective coronary angiography for CAD between FY07 and FY12 in the VA healthcare system. Among 37,674 Veterans undergoing the procedure, 8,384 (22%) had non-obstructive CAD and 20,899 (55%) had obstructive CAD. Findings show:

  • Compared to Veterans with no apparent CAD, Veterans with non-obstructive CAD were at significantly greater risk of myocardial infarction (MI) and all-cause mortality at one year.
  • The one-year risk of MI progressively increased by extent of CAD, rather than abruptly increasing between non-obstructive and obstructive CAD. For example, among Veterans with no apparent CAD, the one-year MI rate was 0.11%, while the one-year MI rate for 1-vessel non-obstructive CAD was 0.24%, increasing to 0.59% for 3-vessel non-obstructive CAD.
  • Age and cardiovascular risk factors (e.g., hypertension, hyperlipidemia, and diabetes) all increased with increasing extent of CAD.

Implications: Findings suggest that non-obstructive CAD is common, confers significant risk for MI and mortality, and warrants immediate consideration of preventative therapies for Veterans with this condition.

Maddox T, Stanislawski M, Grunwald G, et al. Non-obstructive coronary artery disease and risk of myocardial infarction. JAMA. November 5, 2014;312(17):1754-63.

Long-Term Follow-Up of VADT Study Suggests Cardiovascular Benefits of Tight-Glucose Control in Diabetes

Patients with type 2 diabetes have a greatly increased risk of cardiovascular events; therefore, learning whether improved glucose control reduces cardiovascular events is critically important. The Veterans Affairs Diabetes Trial (VADT) previously reported that intensive glucose lowering, compared to standard therapy, did not significantly reduce major cardiovascular events in 1,791 Veterans. VADT participants were randomly assigned to receive either intensive or standard glucose control. The study ended on May 29, 2008, with a median follow-up, 5.6 years. The current study, which included HSR&D investigators and was funded through VA's Cooperative Studies Program, analyzed an additional five years of observational follow-up data on VADT participants (through December 2013), thus achieving a total follow-up of 11.8 years for most study measures. VA, Medicare, and U.S. National Death Index data were used to identify procedures, hospitalizations, and death (cohort, 92% follow-up). The primary outcome was a composite of major cardiovascular events that included: heart attack, stroke, new congestive heart failure, amputation for ischemic gangrene, or cardiovascular-related death. Secondary outcomes included cardiovascular and all-cause mortality. Findings show:

  • Veterans with type 2 diabetes randomized to intensive glucose control for a median of 5.6 years had a significant 17% relative reduction in major cardiovascular events after almost 10 years of total follow-up compared to Veterans who received standard glucose therapy.
  • Intensive glucose control was not associated with a significant decrease in all-cause mortality after almost 12 years of follow-up.

Implications: Results provide further evidence that improved glycemic control can reduce major cardiovascular events. This potential benefit may be considered in conversations with patients, but balanced with the burdens and safety data for the specific glucose-lowering treatment being considered.

Hayward R, Reaven P, Wiitala W, Bahn G, Reda D, Ge L, McCarren M, Duckworth W, and Emanuele N. Follow-up of glycemic control and cardiovascular outcomes in type 2 diabetes. New England Journal of Medicine. June 4, 2015;372(23):2197-2206.

Under-use of Cardiac Rehabilitation for Veterans Hospitalized for Ischemic Heart Disease

Referral to exercise-based cardiac rehabilitation (CR) is one of nine performance measures for the prevention of secondary cardiovascular events after hospitalization for myocardial infarction (MI), percutaneous coronary intervention (PCI), and/or coronary artery bypass grafting (CABG). This study sought to determine: 1) the proportion of Veterans with IHD who participate in CR; 2) whether the presence of an onsite CR program was associated with greater participation; and 3) patient characteristics associated with participation. Study investigators identified Veterans who had been hospitalized in the VA healthcare system for MI, PCI, or CABG during FY07 through FY11. Of the 124 VA facilities in this study, 35 had an onsite CR program. The study's primary outcome was the number of Veterans who participated in one or more CR sessions within 12 months after hospitalization. Investigators also examined patient demographics, body mass index, distance from a VA facility, comorbidities (e.g., hypertension, diabetes), and medications (e.g., beta-blockers, statins).

  • Only 8% of the Veterans in this study who had been hospitalized for MI, PCI, or CABG participated in one or more sessions of outpatient cardiac rehabilitation.
  • Overall, Veterans were more likely to participate in CR if they had been hospitalized at a VA facility with an onsite CR program versus without one (11% vs. 7%). However, participation was extremely low regardless of the presence or absence of an onsite program.
  • Characteristics associated with greater participation in CR included: younger age, being married, higher BMI, living closer to a VA facility, hyperlipidemia, absence of heart failure, absence of chronic kidney disease, and hospitalization for CABG (vs. PCI or MI). After controlling for these variables, the presence of an onsite CR program was associated with 75% greater odds of attending a CR program.

Implications: Findings suggest that new, patient-centered delivery strategies must be developed to solve the challenge of CR under-utilization.

Schopfer D, Takemoto S, Allsup K, Helfrich C, Ho P, Forman D, and Whooley M. Cardiac rehabilitation use among Veterans with ischemic heart disease. JAMA Internal Medicine. October 2014;174(10):1687-1689.

Differences between Men and Women Veterans Undergoing Cardiac Catheterization in VA

Coronary artery disease (CAD) remains the leading cause of death among women in the United States, but little is known about the characteristics and treatment of women Veterans suspected of having clinically significant CAD. This HSR&D study sought to determine whether there were gender differences in clinical characteristics and comorbidities, coronary anatomy and treatment, and procedural complications and long-term outcomes after diagnostic catheterization. Study investigators identified 85,936 Veterans (3,181 women) who underwent initial diagnostic catheterization between 10/07 and 9/12 at any of 77 VA catheterization labs. Investigators then assessed gender differences in demographics, indications, coronary anatomy, cardiac treatments, and outcomes. Findings show:

  • Female Veterans were younger (57 vs 63 years) with fewer traditional cardiovascular risk factors, but had more obesity, depression, and PTSD than male Veterans.
  • Compared to male Veterans, female Veterans had lower rates of obstructive CAD (23% vs 53%), similar or lower rates of procedural complications, and lower rates of all-cause re-hospitalization.
  • Women Veterans had lower mortality at one year, even when adjusted for age, presence of obstructive disease, and multiple comorbidities.

Implications: These findings suggest that a significant portion of women Veterans treated in VA catheterization labs have chest pain not related to obstructive CAD. This may represent a complex interplay of psychological stressors and somatic disease, which suggests further research is needed.

Davis M, Maddox T, Langner P, Plomondon M, Rumsfeld J, and Duvernoy C. Characteristics and outcomes of women Veterans undergoing cardiac catheterization in the Veterans Affairs Healthcare System. Circulation: Cardiovascular Quality and Outcomes. February 24, 2015; ePub ahead of print.

Pharmacist Support Key in Medication Adherence for Veterans Prescribed Dabigatran for Atrial Fibrillation

Atrial fibrillation is the most common cardiac arrhythmia, necessitating treatment with oral anticoagulation in moderate- to high-risk patients to reduce the risk of stroke. Dabigatran is the first of several target-specific oral anticoagulants approved in the U.S., and, unlike warfarin, does not require routine testing to evaluate anticoagulation effect. However, a previous study reported that suboptimal adherence to dabigatran was associated with increased risk of stroke and death. This retrospective study assessed site-level variation in dabigatran adherence and identified practices associated with higher dabigatran adherence within the VA healthcare system. Investigators identified 4,863 Veterans with non-valvular atrial fibrillation who filled dabigatran prescriptions at 67 VAMCs between 2010 and 2012. Interviews were then conducted with anticoagulation or outpatient clinic supervisors, or senior pharmacists at 41 sites. The primary outcome was patient adherence to dabigatran, which was defined by proportion of days covered (ratio of days supplied by prescription to follow-up duration) of 80% or more. Findings show:

  • Among Veterans treated with dabigatran, there was significant site-level variation in medication adherence across VAMCs, with the site average ranging from 42% to 93%.
  • Veterans were more likely to be adherent and without missing doses when they were monitored by VA pharmacists.
  • Longer duration of pharmacist-led monitoring and providing more intensive care to non-adherent patients, in collaboration with the clinician, also improved medication adherence.

Implications: Findings suggest extra patient support (i.e., pharmacist intervention) may significantly improve adherence to dabigatran and all novel or target-specific oral anticoagulants (i.e., dabigatran, rivaroxaban). These data also affirm VA's rich infrastructure of pharmacist-led, specialized anticoagulation may continue to have an important role in maximizing safety, effectiveness, and appropriate use of these new agents, even as warfarin use continues to decline.

Shore S, Ho P, Lambert-Kerzner A, Glorioso T, Carey E, Cunningham F, Longo L, Jackevicius C, Rose A, and Turakhia M. Site-level variation in and practices associated with dabigatran adherence. JAMA. April 14, 2015;313(14):1443-1450.

Turakhai M, Ziegler P, Schmitt S. et al. Atrial fibrillation burden and short-term risk of stroke: A case-crossover analysis of continuously recorded heart rhythm from cardiac electronic implanted devices. Circulation: Arrhythmia Electrophysiology. July 2015; Epub ahead of print.

References:

1. Centers for Disease Control and Prevention. Heart Disease Facts.

2. VA HSR&D's Ischemic Heart Disease Quality Enhancement Research Initiative (IHD-QUERI).

Additional Resources: