Expert Analysis

35% of myocardial infarctions in the U.S. occur in patients 75 years and older, and 11% occur in patients older than 85 years of age. ST elevation myocardial infarction (STEMI) is less common than Non-ST-elevation myocardial infarction (NSTEMI) in older adults, although the absolute numbers of STEMI increase with age.

Older patients, and particularly older women, often present with non-chest pain ischemic symptoms, and, as was the example in the associated Patient Case Quiz, the "GI symptoms" represent myocardial ischemia. Other common presentations are severe dyspnea, fatigue, dizziness, or syncope and not uncommon are confusion and altered cognition.

The electrocardiographic diagnosis of STEMI is frequently complicated by an abnormal baseline electrocardiogram, often reflecting left ventricular hypertrophy, prior MI, conduction system disease, and at times the presence of atrial fibrillation. STEMI presenting as new left bundle branch block is far more common at advanced age.

There is an increased risk of cardiogenic shock with acute STEMI in those older than 70 years of age, with a systolic BP below 120 mm Hg, sinus tachycardia in excess of 110 beats per minute (bpm) or a heart rate less than 60 bpm, and a longer time since symptom onset. Because of this increased risk of cardiogenic shock, intravenous beta blocker therapy is characteristically deferred. However, the standard STEMI therapy of aspirin, clopidogrel, and unfractionated heparin is appropriate, with particular attention to weight-based dosing for the unfractionated heparin. Angiotensin-converting-enzyme (ACE) inhibition and high intensity statin is appropriate. Reperfusion is associated with increased STEMI survival in older adults. PCI is favored over thrombolytic therapy (with data available at least to age 80), with documentation of decreased 30-day mortality. There is particular benefit in the aged patient with anterior MI presenting more than 6 hours after symptom onset or with cardiogenic shock. The risk of hemorrhagic stroke is lesser with percutaneous coronary intervention (PCI) than with thrombolytic therapy; as well, thrombolytic therapy is associated with increased risk of myocardial rupture in patients older than 75 years of age (17% with thrombolysis compared with 5% with PCI). The major benefit of primary PCI is a decrease in risk of ischemic events, and a decreased need for subsequent target vessel revascularization.

Nonetheless, the increased bleeding propensity must be appreciated in older adults. It is uncertain whether this is an age-related vasculopathy involving small hemostasis-maintaining vessels causing impaired vascular healing, loss of anatomic vaso-reactivity, or immune incompetence. The patient factors contributing to bleeding risk include anemia, renal dysfunction, heart failure, and diabetes as well as female gender, low body weight, a prior history of bleeding, and peripheral vascular disease. Prominent for bleeding risk are catheter based interventions and inappropriate dosing of anticoagulants (weight, renal function based).

The post-procedure recommendations are early ambulation and deep vein thrombosis prophylaxis with compression apparatus. Secondary prevention medications are comparable as for younger patients, with high-intensity statin showing greater benefit at age greater than 65 years than at younger age. Referral to cardiac rehabilitation is important, as is intensive patient and family education and communication/information in care transitions.

References

1. Bueno H, Betriu A, Heras M, et al. Primary angioplasty vs. fibrinolysis in very old patients with acute myocardial infarction: TRIANA (TRatamiento del Infarto Agudo de miocardio eN Ancianos) randomized trial and pooled analysis with previous studies. Eur Heart J 2011;32:51-60.
2. O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2013;61;485-510.
3. Alexander KP, Newby LK, Armstrong PW, et al. Acute coronary care in the elderly, part II: ST-segment-elevation myocardial infarction: a scientific statement for healthcare professionals from the American Heart Association Council on Clinical Cardiology: In collaboration with the Society of Geriatric Cardiology. Circulation 2007;115:2570-89.
4. Saunderson CE, Brogan RA, Simms AD, Sutton G, Batin PD, Gale CP. Acute coronary syndrome management in older adults: guidelines, temporal changes and challenges. Age Ageing 2014;43:450-5.
5. Veerasamy M, Edwards R, Ford G, et al. Acute coronary syndrome among older patients: a review. Cardiol Rev 2015;23:26-32.
6. Grosmaitre P, Le Vavasseur O, Yachouh E, et al. Significance of atypical symptoms for the diagnosis and management of myocardial infarction in elderly patients admitted to emergency departments. Arch Cardiovasc Dis 2013;106:586-92.
7. Newell MC, Henry JT, Henry TD, et al. Impact of age on treatment and outcomes in ST-elevation myocardial infarction. Am Heart J 2011;161:664-72.

Keywords: Anemia, Anticoagulants, Atrial Fibrillation, Body Weight, Bundle-Branch Block, Chest Pain, Diabetes Mellitus, Dyspnea, Electrocardiography, Heart Failure, Heparin, Hypertrophy, Left Ventricular, Myocardial Infarction, Percutaneous Coronary Intervention, Peripheral Vascular Diseases, Secondary Prevention, Shock, Cardiogenic, Stroke, Syncope, Tachycardia, Sinus, Thrombolytic Therapy, Ticlopidine, Venous Thrombosis, Aged, Hypertension, Pulmonary

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