Treatment

Once a cardiac catheterization has been performed, the 3 most common therapeutic options are medical therapy, including: lifestyle modification, percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG).

Lifestyle Modification

Patients with documented CAD should actively pursue lifestyle modifications that reduce the risk of future cardiovascular events.

Smoking

Tobacco use is one of the most important reversible contributors to recurrent cardiovascular events. Tobacco use induces endothelial dysfunction, reduces coronary vasoreactivity, increases circulating carbon monoxide levels, impairs functional status, and raises blood pressure.

Exercise

Functional capacity is a strong predictor of major adverse cardiac events. Functional capacity can be improved by following an exercise program that includes at least 30 minutes of exercise 3 or 4 days a week (a daily regimen is considered optimal).

Weight Control

The best weight-management strategy is diet and exercise. Ideal benchmarks are a body mass index between 19 and 25 kg/m2 and a waist circumference ≤ 40 inches for men and ≤ 35 inches for women. Weight loss has a favorable effect on the metabolic syndrome and associated cardiac risk factors including hypertension, high LDL level, low HDL level, blood pressure, endothelial function, vascular inflammation, and glucose intolerance.

Pharmacologic Therapy

Antiplatelet Agents

Aspirin is the mainstay of antiplatelet therapy for patients who have known CAD or symptoms suggestive of CAD. Aspirin inhibits both cyclooxygenase and the synthesis of thromboxane A2. Clopidogrel, a thienopyridine derivative, blocks adenosine diphosphate–induced platelet activation. Clopidogrel is indicated as an alternative for patients who cannot take aspirin or in selected patients who have undergone percutaneous coronary intervention (PCI) with coronary artery stent placement.

Antianginal Agents

Beta blockers, calcium channel blockers, and nitrates are the mainstays of antianginal therapy. Unless contraindications exist, all patients who have a history of angina pectoris should carry sublingual nitroglycerin. Beta blockers are recommended as first-line therapy for the management of stable angina in all patients with established CAD.

Patients who have a history suggestive of vasospastic angina should be treated with a calcium channel blocker or a long-acting nitrate as an initial therapy. Either treatment option can also serve as a substitute for a beta blocker in the presence of traditional angina when intolerable beta-blocker effects ensue.

Nitrates improve exercise tolerance and prolong the time to onset of angina in patients with exertional angina. They are contraindicated in patients who have severe aortic stenosis or hypertrophic cardiomyopathy because they can adversely alter hemodynamics and exacerbate symptoms. Ranolazine may be useful for treating refractory angina pectoris. Unlike beta blockers, calcium channel blockers, nitrates, and ranolazine have not been demonstrated to reduce cardiac event rates or cardiac mortality.

Risk-Factor Management

Hypertension

Management of hypertension in patients with CAD is exceedingly important. Control of blood pressure reduces myocardial oxygen consumption and thereby reduces angina, and it also lowers the incidence of cardiovascular events.

Beta blockers devoid of intrinsic sympathomimetic activity represent first-line antihypertensive therapy for patients with a history of MI or coronary artery disease with angina. Angiotensin-converting enzyme (ACE) inhibitors are indicated for all patients with diabetes mellitus or a history of MI with impaired left ventricular systolic function. In the Heart Outcomes Prevention Evaluation (HOPE) study, high-risk patients for the presence of CAD without a history of MI, who were treated with the ACE inhibitor ramipril, experienced a significant reduction in major cardiac events.

Calcium channel blockers are useful for patients with hypertension and angina despite maximum tolerable administration of beta blockers. The long-acting dihydropyridines are preferred; short-acting preparations should be avoided because they are suspected of increasing the risk of cardiac events via precipitous blood pressure reduction and induction of the coronary steal phenomenon, diverting coronary arterial blood flow from flow-limited myocardial regions.

Hyperlipidemia

Guidelines of the National Cholesterol Education Program (NCEP) have recommended an LDL cholesterol level <70 mg/dL for all patients with coronary artery or other atherosclerotic disease. Patients whose LDL levels are >100 mg/dL should start pharmaceutical therapy. 3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are the recommended first-line agents for patients who have CAD and elevated total and LDL cholesterol levels.

The NCEP also recommends a target HDL cholesterol level >45 mg/dL for men with CAD and >55 mg/dL for women. Patients with the metabolic syndrome (obesity, hypertension, and insulin resistance) often have HDL levels that are¸ ≤35 mg/dL. These patients are at especially high risk for arterial vascular disease. Recommended lifestyle changes for these patients include regular exercise and weight loss, which are 2 of the most effective ways to raise HDL levels. If lifestyle changes fail to increase HDL levels to their target, drug treatment with a fibrate or niacin should be considered, particularly in patients whose triglyceride levels are >200 mg/dL.

Diabetes Mellitus

Diabetic patients with CAD have a particularly high risk for recurrent cardiovascular events, and they should be targeted for aggressive risk-factor modification. The American Diabetes Association recommends enhanced blood glucose control and monitoring with a hemoglobin A1c level lower than 7%.

Surgical Management: Revascularization

The primary revascularization options are PCI and CABG surgery. The most common PCI techniques are percutaneous transluminal coronary angioplasty and coronary stenting. A major limitation of PCI is restenosis at the intervention site. This represents the body’s response to local injury with an exaggerated neointimal proliferative response. The use of drug-eluting stents, aspirin, clopidogrel, and glycoprotein IIb/IIIa inhibitors lowers the rate of restenosis to <10% at 6 months in optimal circumstances.

The most common conduits for CABG are the saphenous vein and the internal thoracic (mammary) artery. The long-term patency rates of internal thoracic artery grafts are superior to those of venous grafts.

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