• Most patients with peripheral vascular disease are managed medically. Endovascular procedures with balloon angioplasty and stenting are less invasive procedures but are also less durable and have technical limitations when the blockage is extensive.
• The goal of lower extremity bypass is to improve blood flow, reduce pain, improve functional ability and quality of life, and prevent amputation. Common causes include:
  • Arterial occlusive disease due to atherosclerosis; most common
  • Thromboembolic, inflammatory, or traumatic events. Femoral and popliteal artery aneurysms and pseudoaneurysms are often repaired to prevent thromboembolic events as well as rare ruptures.
  • Advential cysts, entrapment.
  • As part of tumor resections
• The procedure entails creating an alternate conduit for blood flow to circumvent the area of blockage and restore direct flow to the lower leg and foot. The conduit can include harvested veins (saphenous or other vein from the arm or leg) or an artificial, prosthetic graft.
• Acute occlusion is a surgical emergency and is treated with embolectomy, thrombolysis, or bypass.

• Usually supine
• Occasionally other positions may be required, such as prone for some popliteal aneurysms.

• Sufficient to expose the proximal and distal anastomosis
• Additional incisions (often long) for the vein harvest may be needed, though this may be minimized with in situ grafts or endovascular harvests.

Highly variable (1 hour to all day) depending on the extent of bypass and the anatomic intricacies of the procedure

• Usually minimal blood loss
• Revision procedures, infected grafts, or intraoperative difficulties can increase blood loss.

3–5 days in uncomplicated cases

In patients lacking suitable autologous veins (prior harvest or excision), synthetic graft (e.g., PTFE) or cryopreserved vessels may be needed. In an infected field, cryovessel is preferred over PTFE.

Incidence

Peripheral arterial disease (PAD) incidence increases with age.

Prevalence

• PAD estimates vary widely; American Heart Association (AHA) states about 8 million Americans.
• PAD affects approximately 20% of adults over the age of 55 years.

• Per National Surgical Quality Improvement Program (NSQIP), in 2004, major 30-day morbidity was 18.7%.
  • Wound complications (~75% of all complications): Dehiscence, wound and organ space infection, sepsis, bleeding, and graft failure
  • Systemic complications: Failure to wean, reintubation, pneumonia, renal failure, pulmonary embolism, stroke, coma, cardiac arrest, and deep venous thrombosis
• Morbidity was also higher in those undergoing surgery for limb ischemia: 30.1% (1).

• Operative mortality of approximately 1–3%
• Per NSQIP data, mortality was 2.7% in 2004; patients with critical limb ischemia had an increased mortality of 3.6% (1).

History

Focus on evidence of atherosclerotic vascular disease in the heart, brain, and kidneys. Symptoms of cardiac disease may be masked since claudication may limit exertion.

Signs/Physical Exam

• Lower extremity pallor, cyanosis, dependent rubor, coolness, atrophy, and decreased hair or nail growth may be noted with diminished or absent distal pulses in the evaluation by the surgical consult.
  • Evaluation by ankle brachial index (the ratio of the ankle to the arm pressure): A ratio <0.9 or >1.3 is abnormal, and 0.4 indicates severe peripheral vascular disease.
  • Further evaluation often leads to angiography along with attempts at angioplasty, stenting, or other minimally invasive vascular procedures.
• Cardiac exam for evidence of heart failure
• Carotid bruits can be significant, though often a carotid duplex has already been performed.
• Pulmonary exam may indicate the adverse effects of smoking.

Labs/Studies

• Electrolytes, BUN, creatinine, glucose
• EKG
• CXR
• Cardiac stress testing, echocardiogram, and/or cardiac catheterization data may have been performed as part of a cardiac evaluation.

• Perioperative beta-blockade may be started (2) [B].
  • However, studies with the most favorable outcomes initiated beta-blockade at least a week before surgery (3) [B].
  • A more recent study demonstrated reduced incidence of myocardial infarction, but increased risk of stroke and a higher death rate (4) [B]. The dose of beta-blocker, however, was criticized as being relatively high.

• Consent for possible blood transfusion, planned or possible invasive monitors
• Review of the risk of cardiac and cerebral vascular complications

Routine prophylactic antibiotics for skin organisms unless already on a specific antibiotic for limb infection

• General, epidural, spinal, and even nerve blocks have been successfully utilized.
• Epidurals have the possible advantage of avoiding airway instrumentation and the potential stress of general anesthesia as well as improved graft patency. Reductions in cardiac and pulmonary complications and graft thrombosis have been inconsistently seen in a variety of studies.
• General anesthesia offers a secure airway, avoids the hemodynamic changes of a sympathectomy, and may be better tolerated (and preferred by patients) in longer procedures.
• Peripheral nerve blocks may offer an alternative to neuraxial techniques when anticoagulants/antiplatelets therapy contraindicates neuraxial placement.

• Arterial line monitoring is useful for blood pressure monitoring and frequent blood draws.
• A urinary catheter is frequently placed in expected lengthy procedures and to assist in monitoring volume status.
• Consider central line monitoring per the patient's underlying disease. Pulmonary artery catheterization and/or transesophageal echocardiography may be indicated in more severe cardiac disease.

A slow, controlled induction may produce fewer or more tightly controlled hemodynamic swings.

Hemodynamic stability is critical to preserve perfusion through the cerebral, myocardial, and renal vessels.

• Extubation at the end of the case is usually feasible.
• A hemodynamically smooth emergence and extubation may be beneficial in the setting of cardiac disease.