Nonobstructive Coronary Artery Disease Associated With Increased Risk of Heart Attack, Death

In a study that included nearly 38,000 patients, those diagnosed with nonobstructive coronary artery disease (CAD) had a significantly increased risk of heart attack or death one year after diagnosis, according to a study in the November 5 issue of JAMA.

Nonobstructive coronary artery disease (CAD) is atherosclerotic plaque that would not be expected to obstruct blood flow or result in anginal symptoms (such as chest pain). Although such lesions are relatively common, occurring in 10 percent to 25 percent of patients undergoing coronary angiography, their presence has been characterized as “insignificant” or “no significant CAD" in the medical literature. However, this perception of nonobstructive CAD may be incorrect, because prior studies have noted that the majority of plaque ruptures and resultant myocardial infarctions (MIs; heart attacks) arise from nonobstructive plaques. Despite the prevalence of nonobstructive CAD identified by coronary angiography, little is known about its risk of adverse outcomes, according to background information in the article.

Thomas M. Maddox, M.D., M.Sc., of the VA Eastern Colorado Health Care System, Denver, and colleagues compared heart attack and mortality rates among patients with nonobstructive CAD, obstructive CAD, and no apparent CAD. The patients included in the study were all U.S. veterans who underwent elective coronary angiography for CAD between October 2007 and September 2012 in the Veterans Affairs health care system. Patients with prior CAD events were excluded. CAD extent was defined by degree of vessel narrowing and distribution (1, 2, or 3 vessel).

During the study period, 37,674 patients underwent elective coronary angiography for indications related to CAD; of those, 22.3 percent had nonobstructive CAD and 55.4 percent had obstructive CAD. Within 1 year, 845 patients died and 385 were rehospitalized for MI. The researchers found that the 1-year MI risk progressively increased by the extent of CAD, rather than abruptly increasing between nonobstructive and obstructive CAD. Patients with nonobstructive CAD had an associated risk of MI that was 2-to 4.5-fold greater than among those with no apparent CAD. Similar observations were seen with 1-year mortality and the combined outcome of 1-year MI and death.

“These findings highlight a need to recognize that nonobstructive CAD is associated with significantly increased risk for MI, consistent with prior biologic studies indicating that a majority of MIs are related to nonobstructive stenosis [narrowing of an artery]. Correspondingly, these results reveal the limitations of a dichotomous [divided into two parts] characterization of angiographic CAD into ‘obstructive’ and ‘nonobstructive’ to predict MI and highlight the importance of preventive strategies such as pharmacotherapy treatments and lifestyle modifications to mitigate these risks,” the authors write.

(doi:10.1001/jama.2014.14681)

Study Finds Brief Interventions Ineffective for Reducing Unhealthy Drug Use

Research at the Boston Universsity School of Public Health suggests that screening and brief intervention for illicit drug use and prescription drug misuse is not effective in preventing drug abuse.

However, Ralph Hingson, Sc.D., M.P.H., of the National Institute on Alcohol Abuse and Alcoholism, Bethesda, Md., and Wilson M. Compton, M.D., M.P.E., of the National Institute on Drug Abuse, Rockville, Md., commented on the findings of the studies that examined the effectiveness of brief interventions for drug use.

“Although these studies offer no direct evidence of effectiveness for universal drug screening, brief intervention, and referral to treatment in primary care settings, exploring drug use with patients should remain a priority in primary care. The goal for clinical research is to develop and test new interventions with potential for benefiting patients. Drug screening and brief intervention research that focuses on adolescents and young adults is especially needed because rates of marijuana use among young people and the potency of marijuana have increased at the same time that recognition among youth of the health risks of marijuana use have declined.”

“If brief interventions are insufficient, then easily accessible treatment services with long-term follow-up may be needed, as will development of efficient primary care referral approaches to address risky substance use and related physical and mental comorbidities.”

Richard Saitz, M.D., of the Boston University School of Public Health, and colleagues tested the effectiveness of two brief counseling interventions for unhealthy drug use (any illicit drug use or prescription drug misuse) among primary care patients identified by screening.

The United States has invested substantially in screening and brief intervention for illicit drug use and prescription drug misuse, based in part on evidence of efficacy for unhealthy alcohol use. However, it is not a recommended universal preventive service in primary care because of lack of evidence of efficacy, according to background information in the article.

The researchers randomly assigned 528 adult primary care patients with unhealthy drug use to one of three groups: to receive a brief negotiated interview (BNI), which was a 10- to 15-minute structured interview conducted by health educators; an adaptation of motivational interviewing (MOTIV), which was a 30- to 45-minute intervention based on motivational interviewing with a 20- to 30-minute booster conducted by masters-level counselors; or no brief intervention. All study participants received a written list of substance use disorder treatment and mutual help resources. At the beginning of the study, 63 percent of participants reported their main drug was marijuana, 19 percent cocaine, and 17 percent opioids.

For the primary outcome (number of days of use in the past 30 days of the self-identified main drug), there were no significant differences between the BNI, MOTIV or control groups (adjusted average days using the main drug at 6 months, 11, 12 and 12 days, respectively). In addition, there were no significant between-group differences overall or in stratified analyses at 6 weeks or 6 months in drug use consequences, injection drug use, unsafe sex, health care utilization (hospitalizations and emergency department visits, overall or for addiction or mental health reasons), or mutual help group attendance.

The authors write that despite the potential for benefit with a brief intervention, drug use differs from unhealthy alcohol use in that it is often illegal and socially unacceptable, and is diverse—from occasional marijuana use, which was illegal during this study, to numerous daily heroin injections. “Prescription drug misuse is particularly complex, with diagnostic confusion between misuse for symptoms (e.g., pain, anxiety), euphoria-seeking, and drug diversion. Brief counseling may simply be inadequate to address these complexities, even as an initial strategy.”

“These results do not support widespread implementation of illicit drug use and prescription drug misuse screening and brief intervention.”

The research and comments are included in the recent issue of JAMA, the Journal of the American Medical Association.