Chapter 20: Chronic Stable Angina & Myocardial Infarction Therapy

The underlying pathology is primarily atherosclerosis, a progression of lipid metabolism disorder that narrows coronary arteries through stages, starting with a fatty streak and culminating in a complicated lesion prone to rupture and thrombus formation. Key risk factors that contribute to this pathology include nonmodifiable elements like age, heredity, and gender, as well as several modifiable factors such as cigarette smoking, hypertension, dyslipidemia, diabetes, obesity, and physical inactivity. The diagnostic process begins with a comprehensive health history, focusing on chest pain characteristics and triggers, followed by diagnostic tests like electrocardiography (ECG), stress testing, and the assessment of cardiac biomarkers, such as troponin, especially in acute presentations. Treatment strategies prioritize symptom relief, preventing further episodes, arresting CHD progression, and prolonging survival, anchored by essential nonpharmacologic interventions like smoking cessation and regular exercise. Pharmacologic management utilizes several classes of medications: Beta blockers are typically the first choice for chronic prevention, as they decrease cardiac workload and oxygen demand. Short-acting nitrates (e.g., sublingual nitroglycerin) are vital for managing acute anginal attacks by causing widespread vasodilation, while long-acting nitrates used for chronic prophylaxis necessitate a daily nitrate-free period to circumvent drug tolerance. If monotherapy is insufficient, calcium channel blockers (CCBs)—which are particularly effective for vasospastic angina—or long-acting nitrates are added. Furthermore, daily antiplatelet therapy, primarily aspirin, is mandatory for all patients with ischemic heart disease to reduce MI risk, often supplemented by P2Y12 inhibitors in acute coronary syndromes (ACS). In the immediate management of ACS, rapid restoration of coronary blood flow using antiplatelets, anticoagulants, and, if necessary, reperfusion therapies (PCI or fibrinolytics for STEMI) is critical. Long-term maintenance therapy also frequently incorporates ACE inhibitors or ARBs, especially for patients with coexisting conditions like heart failure or diabetes.