Chapter 2: Cardiovascular Emergencies

DISORDERS OF ARTERIAL CIRCULATION

Peripheral Arterial Disease

The vast majority of peripheral arterial disease (PAD) in the United States and Western Europe is due to atherosclerotic arterial disease. Factors contributing to the development of atherosclerosis include cigarette smoking, hyperlipidemia, hypertension (HTN), and diabetes mellitus.

Thromboangiitis obliterans (Buerger disease) is an idiopathic cause of PAD more commonly seen in the Middle and Far East. It occurs almost exclusively in smokers, and is most common in young males.

PATHOPHYSIOLOGY

• Atherosclerotic PAD: Peripheral vascular atherosclerotic lesions reduce arterial luminal diameter and blood flow → tissues ischemia when blood flow does not meet O₂ demand

• Buerger disease: Inflammation of small and medium-size vessels → thrombus formation and subsequent fibrosis → tissue ischemia

SYMPTOMS

• Claudication: Fatigue, pain, or weakness in involved extremity or digit.

• Exertional symptoms become rest symptoms as disease progresses.

• Painful ulcerations.

• Leriche syndrome: Triad of bilateral hip claudication, erectile dysfunction, absent femoral pulses = aortoiliac occlusive disease.

• Buerger disease can present with claudication of distal extremities, isolated joint pain, or superficial thrombophlebitis.

EXAMINATION

Patients with PAD will exhibit muscular atrophy, shiny or scaly skin, evidence of poor wound healing, digital ulcerations, loss of hair follicles, diminished pulses, and slowed capillary refill.

DIFFERENTIAL

• Spinal stenosis or nerve root compression is another cause of intermittent claudication.

• Ethyl alcohol (EtOH) abuse, diabetes, and chemotherapy may cause neuropathic pain.

DIAGNOSIS

• Suspect based on history and examination.

• Ankle brachial index (ABI) ≤ 0.9 is highly sensitive and specific for the diagnosis.

• Duplex ultrasound, comprised of Doppler waveform analysis and color-coded ultrasound imaging, is a noninvasive and accurate diagnostic modality for both PAD and venous disease.

• Arteriography has long been the definitive test for peripheral arterial anatomy but is invasive and associated with contrast-related and catheter-related complications.

• Shows diffuse atherosclerosis, irregular cutoff of contrast flow, increased collaterals.

TREATMENT

• Risk-factor modification: Smoking cessation, antihypertensive therapy, lipid-lowering therapy, glycemic control

• Antithrombotic therapy (aspirin, clopidogrel, warfarin)

• Immediate surgical intervention if limb-threatening ischemia:

  • Stents or arterial bypass surgery

• Wound care for ulcerations

• Smoking cessation = Only effective therapy for Buerger disease