Screening for Cardiovascular Disease
Coronary heart disease (CHD) remains the leading cause of death among adult men and women in the United States. According to the CDC, one person dies every 36 seconds in the United States from heart disease which translates into about 659,000 annual deaths – about 1 in every 4 deaths (link: https://www.cdc.gov/heartdisease/facts.htm). Further, advanced obstructive coronary heart disease (CHD) can exist with minimal or no symptoms. The first clinical manifestations of CHD such as a heart attack (myocardial infarction) are often associated with significant morbidity and/or mortality.
Screening begins early, at the age of 20, with the primary purpose of identifying patients whose prognosis could be improved with an intervention. Periodic risk assessment (initially every 3 to 5 years but after age 40 an annual re-evaluation would be warranted) identifies specific risk factors and offer specific guidance on the appropriate management of such (eg, dietary modifications for hypertension or high cholesterol) as well as strategies to reduce one’s overall risk risk (eg, maintaining a healthy diet, quitting smoking, and regular exercise). For all individuals, a handful of traditional risk factors are assessed:
- High blood pressure (Hypertension)
- Cigarette smoking
- Diabetes mellitus (DM)
- Hyperlipidemia (High Cholesterol, both familial and lifestyle. LDL cholesterol exceeding 160 mg/dL)
- Early family history of heart disease, heart attack or stroke (males, age <55 years; females, age <65 years)
In addition to these usual risk factors, there exist ‘risk enhancing’ characteristics as well. These include:
- Increased waist circumference
- Elevated triglycerides (>150 mg/dL) or persistently elevated primary hypertriglyceridemia (≥175 mg/dL)
- Elevated blood pressure without a formal diagnosis of hypertension
- Elevated fasting glucose
- Low HDL (<40 mg/dL in males; <50 mg/dL in females)
- Chronic kidney disease (eGFR 15 to 59 mL/min/1.73 m2 with or without albuminuria; not treated with dialysis or kidney transplantation)
- Chronic inflammatory conditions, such as psoriasis, RA, lupus, or HIV/AIDS
- History of premature menopause (before age 40 years)
- History of pregnancy-associated conditions that increase later cardiac risk, such as preeclampsia
- High-risk race/ethnicity (eg, South Asian ancestry)
- Elevated high-sensitivity (“cardiac specific”) C-reactive protein (≥2.0 mg/L)
- Ankle-Brachial Index (<0.9).
- Elevated apoB (≥130 mg/dL)
- Elevated Lp(a) (≥50 mg/dL)
Other special populations may be candidates for additional screening and these include pre-participation evaluations for athletes (both recreational and competitive), public safety (such as airline pilots, bus drivers, truck drivers) or high risk occupations (scuba divers).
There are a number of different screening tests available and include both imaging tests as well as “stress” tests. In general, if a patient can exercise, it is best to have them exercise rather than to perform a pharmacologic stress test. An exercise stress test is typically performed on a treadmill or recumbent bicycle and is a test we offer in our office. For those who are unable to exercise, stress radionuclide myocardial perfusion imaging can be performed.
Additionally, there are imaging tests that can be used as adjuncts to stress testing modalities. Among these is a coronary artery calcium (CAC) scan which provides a numeric value quantifying the amount of calcium in the coronary (heart) arteries (blood supply). As calcium deposits tend to follow cholesterol plaquing, a CAC scan can measure the amount and distribution of cholesterol potentially identifying a blockage. A score of “0” is a perfect score, indicating no calcium whatsoever. CAC scoring is most helpful in patients who require screening and who are at intermediate or borderline risk with the presence of risk-enhancing factors, such as a family history of very early coronary artery disease. A CT angiography also provides a CAC score but allows for more detailed imaging of the arteries as well.
In our office we employ an ultrasound imaging technique termed Carotid Intima-Media Thickening (CIMT) measurement which helps evaluate one’s cardiovascular health status. Interest in ultrasound detection of early cardiovascular disease began with autopsy studies in adolescents and young adults, which revealed that atherosclerosis is present early in life and precedes clinically manifested cardiovascular events. Therefore, non-invasive arterial imaging has the potential to provide information on arterial wall structure in persons of all age groups as a continuous variable to describe all stages of atherosclerosis progression and regression CIMT is a widely available, safe, and reproducible measure to assess cardiovascular disease risk in the individual patient. It is also a well-validated research tool to investigate atherosclerosis development in epidemiological studies, provide insight in cardiovascular disease risk in specific populations, and to evaluate efficacy of preventive cardiovascular therapies in clinical trials.