Atherosclerosis in Adult Congenital Heart Disease

Background: Several studies have demonstrated an increasing burden of atherosclerotic cardiovascular disease (ASCVD) in individuals with adult congenital heart disease (ACHD). The number of hospitalizations for ACHD has increased more for coronary artery disease than for any other disease process (by 119% from 1998 to 2005) [1]. Coronary artery disease is currently the second most common cause of hospital admission for ACHD in the United States (arrhythmia is the first) [1]. As of 1990, myocardial infarction has replaced arrhythmia as the leading cause of death for non-cyanotic lesions [2]. A Canadian population-based cohort study reported a 7% rate of myocardial infarction in ACHD as compared to an age-matched prevalence of 5% [3]. A single center in Canada performed a retrospective chart review which revealed that 14% of their ACHD population had angiographically confirmed coronary artery disease before the age of 40 [4]. Traditional risk factors for ASCVD in ACHD: An estimated 85% of children with CHD now survive into adult life [5]. As the ACHD population ages, age alone will drive an increasing risk of atherosclerosis. 80% of individuals with ACHD have at least one ASCVD risk factor: Notably, studies have indicated a higher prevalence of hypertension and diabetes mellitus (DM) than in the general population and age-matched controls but a lower prevalence of smoking and obesity [6–8]. Other studies, however, have indicated that children born with CHD, who traditionally experienced failure to thrive and low-weight issues, are now becoming overweight at rates similar to that of the general pediatric population, which portends similar rates of obesity in adulthood [9, 10]. The risk of diabetes is higher in patients with cyanotic ACHD than acyanotic ACHD. It is hypothesized that hypoxia negatively impacts glucose metabolism [11]. Coarctation of the aorta is often associated with systemic hypertension, even after repair [12]. Additional risk factors unique to ACHD: Certain congenital heart defects are associated with an increased risk of atherosclerotic coronary artery disease due to the pathophysiology of their defect, such as coarctation of the aorta [12, 13]. Other patients may be at risk because of coronary artery reimplantation that is required in reparative procedures, such as in the arterial switch operation for transposition of the great arteries [14]. Patients who undergo multiple palliative procedures may be exposed to repeated episodes of ischemia-reperfusion injury [15]. Given the complexity of ACHD patients, it is possible that primary prevention is not prioritized (either by limited time for clinicians or lack of understanding by patients) in clinic visits. It has been demonstrated that in a tertiary care center, ACHD patients are less likely to receive statin prescriptions for guideline-based primary prevention than non-ACHD patients (Fig. 39.1) [16]. Diagnosis and management: ACHD patients should have the benefit of lifelong cardiovascular preventative care and theoretically, ideal risk factor modification. Vigilance regarding risk factor modification, measuring of HbA1c and lipid panels, and primary prevention with aspirin and statin therapies must become a part of routine care of the ACHD patient. Guidelines for HMG CoA reductase inhibitor (statin) use for adults ages 40–75 years should be followed unless significant contraindications exist. These include: Moderate-intensity statin prescription for adults ages 40–75 years with DM. High-intensity statin for adults ages 40–75 with DM and ASCVD risk >7.5% at 10 years. In patients without DM, moderate-intensity statin for ASCVD Risk 5–7.5% In patients without DM, moderate- to high-intensity statin for ASCVD Risk >7.5% USPSTF guidelines recommend low-dose aspirin for primary prevention of cardiovascular disease and colorectal cancer in adults ages 50–59 years with ASCVD risk >10% at 10 years.