Noninvasive Cardiovascular Risk Assessment of the Asymptomatic Diabetic Patient: The Imaging Council of the American College of Cardiology

Abstract

Increased cardiovascular morbidity and mortality in patients with type 2 diabetes is well established; diabetes is associated with at least a 2-fold increased risk of coronary heart disease. Approximately two-thirds of deaths among persons with diabetes are related to cardiovascular disease. Previously, diabetes was regarded as a "coronary risk equivalent," implying a high 10-year cardiovascular risk for every diabetes patient. Following the original study by Haffner et al., multiple studies from different cohorts provided varying conclusions on the validity of the concept of coronary risk equivalency in patients with diabetes. New guidelines have started to acknowledge the heterogeneity in risk and include different treatment recommendations for diabetic patients without other risk factors who are considered to be at lower risk. Furthermore, guidelines have suggested that further risk stratification in patients with diabetes is warranted before universal treatment. The Imaging Council of the American College of Cardiology systematically reviewed all modalities commonly used for risk stratification in persons with diabetes mellitus and summarized the data and recommendations. This document reviews the evidence regarding the use of noninvasive testing to stratify asymptomatic patients with diabetes with regard to coronary heart disease risk and develops an algorithm for screening based on available data.

Keywords: coronary CT; diabetes; echocardiography; exercise testing; nuclear imaging.

FIGURE 1. Annualized Cardiac Mortality Among Patients With DM or CAD (History of Myocardial Infarction or Coronary Revascularization)

Diabetes mellitus (DM) patients without coronary artery disease (CAD) and with coronary flow reserve (CFR) <1.6 have the same risk as patients without DM or CAD. In contrast, diabetic patients with CFR <1.6 have essentially the same risk as those with CAD. Reprinted with permission from Murthy et al. (85).

FIGURE 2. Algorithm for Screening Persons With Diabetes Mellitus

An algorithm based upon the recommendations of the 2010 ACCF/AHA Guideline for Assessment of Cardiovascular Risk in Asymptomatic Adults (19), with a suggestion to perform stress imaging if the coronary artery calcium score is significantly elevated.

CENTRAL ILLUSTRATION. Approach to Risk Assessment of Diabetic Patients

As discussed in the text several imaging modalities have been tested to risk stratify asymptomatic diabetic patients but few have provided valuable prognostic information. Diabetic women and diabetic patients with chronic kidney disease are at particularly high risk of cardiovascular complications. ESRD = end-stage renal disease; IMT = intima-media thickness.