Cardiovascular Biomarkers and Imaging in Older Adults: Ten P
The following are ten points to remember from the American College of Cardiology, National Institute on Aging, and American Geriatrics Society workshop entitled "Diagnostic Testing in Older Adults with Cardiovascular Disease".

1. Interpretation of diagnostic tests in older adults is often challenging. Age-associated physiologic changes, comorbid diseases, and geriatric syndromes may affect the sensitivity, specificity, and predictive value of specific diagnostic tests and can vary substantially from those in younger individuals.

2. The ranges of "normal" for biomarkers (e.g. natriuretic peptides, D-dimer) and imaging metrics (e.g. relative wall thickness, E/A ratio on echo) are often broader in older populations such that they overlap with the abnormal range of younger adults, thereby reducing specificity.

3. Additional factors that influence levels of biomarkers with age are declining renal function, changes in body composition (especially decline in lean body mass), hormonal changes, left ventricular hypertrophy and degree of myocardial fibrosis.

4. Ambient cardiac troponin (cTn) levels increase with age; as a result, the specificity and positive predictive value (PPV) for cTn greater than 99th percentile both decrease in older populations. Thus, age and sex-specific criteria for diagnosing myocardial infarction are needed.

5. B-type natriuretic peptide (BNP) and NT-proBNP are useful for evaluating heart failure in older adults when levels are either low (NT-proBNP less than 300 pg/mL) or very high (NT-proBNP greater than 1800 pg/mL in individuals 75 years of age or older); intermediate "gray zone" levels have reduced PPV and require supporting evidence to confirm the diagnosis of heart failure.

6. Aging is associated with alterations in echocardiographic parameters. Left ventricular (LV) mass increases while LV volume decreases, resulting in age-related concentric remodeling. Normal aging is associated with grade I diastolic dysfunction (impaired relaxation), characterized by a decrease in the mitral valve inflow E/A ratio and the tissue Doppler e' velocity.

7. The interpretation of stress testing in older adults can be difficult as the pretest probability can vary substantially in the setting of atypical symptoms, limited physical function, baseline electrocardiogram (ECG) abnormalities, resting wall motion abnormalities and reduced image quality. While pharmacological stress testing has strong diagnostic and prognostic validation for ischemic heart disease in older adults, the exercise stress test, when feasible, provides broader clinical insights into level of physical conditioning and physiologic response to exercise.

8. The role of screening tests and tools, including biomarkers, imaging, wearables, and cell phone apps, for detecting cardiovascular disease (CVD) in older adults without known disease is currently unknown but is an emerging area of interest and investigation.

9. Incorporating patient preferences and goals of care into a shared decision-making process is vital in older adults, including a discussion of potential benefits and harms of testing, as well as the potential for downstream testing or procedures based on initial test results.

10. Research is needed to define normal ranges more accurately for common diagnostic tests in older adults, to delineate the utility of diagnostic tests in this population, and to better align diagnostic testing for CVD with the needs and priorities of an aging population.