Cardiac Risks in the Elderly Patient
When elderly patients are admitted to the hospital for suspected acute coronary syndrome (ACS) or unstable angina (UA), their pretest probability of coronary artery disease (CAD) and their risk of future cardiac events are higher than those of younger individuals. Hospitalists should understand the specific issues, such as decreased mobility, that might limit the types of cardiac assessment tools used for elderly patients, as well as how cardiac testing results add to clinical factors to inform subsequent patient care. The approach to these patients also must include consideration of their general medical and mental status and their anticipated life expectancy.1
RISK ASSESSMENT OF CAD IN THE ELDERLY
Some of the common scenarios in which elderly patients might present with ACS include presentation in the emergency department (ED) for chest pain, inpatient presurgical assessment, inpatient for another heart-related issue, or inpatient ACS unrelated to admission. It is important to note that atypical symptoms (defined as an absence of chest pain) occur more often among elderly patients with ACS than with younger patients with ACS.2 Atypical symptoms might include dyspnea, diaphoresis, nausea and vomiting, and syncope. If these are the initial complaints amongst elderly patients,2 physicians might not necessarily think to assess the patient’s heart at first. In such circumstances, myocardial infarction (MI) might go undetected. ACC/AHA guidelines say all patients ≥70 years of age are at intermediate risk and patients ≥75 years of age are at high risk for short-term death or nonfatal MI.2
MI estimation is based on the patient’s age, findings on initial physical examination, electrocardiogram (ECG), and laboratory evaluation.1 Because of the higher mortality rate of the general population in this age group, upward adjustment of the intermediate-risk group to levels more than the 1% to 3% as used for general populations might be appropriate.3 ACC/AHA and ESC guidelines recommend that a 12-lead ECG be obtained immediately (within 10 minutes) in patients with chest discomfort or other symptoms consistent with ACS.1 ST-segment elevation myocardial infarction (STEMI) is an ACS in which immediate reperfusion therapy (thrombolysis or percutaneous coronary intervention [PCI]) should be considered.1 In this scenario, PCI is the better option for reperfusion. It is important to understand that elderly patients with STEMI infarction more often have relative and absolute contraindications to reperfusion, so eligibility for reperfusion declines with age.5 Though guidelines are published in an effort to direct care of elderly patients with ACS, careful consideration of each individual case is of great importance in this population.
In contrast to STEMI, UA and NSTEMI are closely related ACSs that are characterized by an imbalance between myocardial oxygen supply and demand and do not immediately call for consideration of reperfusion.1 Unstable angina is characterized by increases in the severity or length of anginal attacks or a decrease in the exertion required to precipitate an attack, especially when symptoms were previously stable.6 Elderly persons with UA/NSTEMI tend to have atypical presentations of disease, substantial comorbidity, ECG stress tests that are more difficult to interpret, and different responses to pharmacological agents compared with younger patients.1 Age has a profound effect on the presentation of NSTEMI, according to the National Registry of Myocardial Infarction (NRMI), which showed that the proportion of NSTEMI ACS patients presenting with non-diagnostic ECGs increased to 43% from 23% for those <65 versus those ≥85 years of age.2
THE VALUE OF MPI IN ELDERLY PATIENTS
Myocardial perfusion imaging (MPI) can be an important tool in diagnosing cardiac conditions in elderly patients, especially if they are asymptomatic. The use of MPI in asymptomatic individuals with high-risk clinical profiles, particularly in patients in whom classic angina symptoms are infrequent or non-predictive (eg, the elderly), might be appropriate and yield incremental value.7 Unfortunately, MPI is underutilized in this population.8
CHALLENGES IN DIAGNOSING CAD IN ELDERLY PATIENTS
One of the more significant challenges in detecting cardiac ischemia in elderly patients is that they might not be able to undergo exercise stress testing. Even elderly patients who are able to exercise might not be able to reach the desired heart rate, which is 85% of their maximal predicted heart rate (based on age). In these cases, pharmacologic stress testing, which mimics vasodilation during exercise, could be a viable alternative to exercise stress. Single photon emission computed tomography (SPECT) MPI is an imaging modality compatible with pharmacologic stress testing. As you may well know, a potential challenge in administering pharmacologic stress (and other drugs) in elderly patients is the difficulty in finding viable veins for a successful IV.
In elderly patients who are at risk for cardiac events, advanced age alone increases risk. Therefore, it is important to understand the many implications of physical examination and medical history to ensure proper care. Cardiac imaging might be a powerful tool in determining a course of treatment for UA/NSTEMI patients, especially if they are asymptomatic or have undergone a non-diagnostic ECG. Careful consideration of patient information, as well as consultations with PCPs and specialists, will allow for the most informed clinical decision-making for the patient and their heart.
Matthew Landler, MD, from the Northwestern University Feinberg School of Medicine, is the consultant for The Heart and Hospital Medicine series. Dr. Landler is a consultant for Astellas Pharma US, Inc.