Comprehensive Vascular Assessment for Lower Extremity Wounds

Limitations of ABI in Wound Assessment

The American College of Cardiology notes that ABI may be normal in nearly one-quarter of patients with chronic limb-threatening ischemia, and 29% of patients with chronic limb-threatening ischemia have an ABI between 0.70 and 1.40, making ABI alone unreliable for wound assessment 1
The concordance between ABI and toe pressure/toe-brachial index among patients with chronic limb-threatening ischemia is poor, with only 58% of patients who meet criteria for abnormal toe pressures presenting with abnormal ABIs 1

The American College of Cardiology recommends performing ABI measurement as a first-line test for patients with lower extremity wounds 2, 3
Palpate pedal pulses as part of the comprehensive vascular examination, as recommended by the American College of Cardiology 4
Toe pressure/TBI measurements should be performed, especially when ABI is normal or elevated, due to noncompressible vessels, as suggested by the American College of Cardiology 1, 5
Abnormal toe pressures reflect severe ischemia and are associated with decreased likelihood of wound healing, according to the American College of Cardiology 1
A TcPO2 >30 mm Hg or an SPP >40 mm Hg can predict wound healing potential, as noted by the American College of Cardiology 1

For all lower extremity wounds, the American College of Cardiology recommends performing ABI measurement, and if ABI ≤0.90, PAD is confirmed, but additional testing is needed to assess wound healing potential 1, 2, 3
If ABI >1.40, vessels are noncompressible, and TBI is mandatory, as recommended by the American College of Cardiology 3, 5

Relying solely on ABI may miss significant arterial disease in patients with diabetes or advanced age due to arterial calcification causing falsely elevated readings, as warned by the American College of Cardiology 3, 5
Perfusion assessment measures should be obtained in a warm room to prevent arterial vasoconstriction in response to cold, which could lead to inaccurate results, as noted by the American College of Cardiology 1

The American College of Cardiology recommends ABI testing as a first-line test for all patients with lower extremity wounds to establish diagnosis of peripheral artery disease (PAD) 6
The American College of Cardiology suggests that the resting ABI should be used to establish lower extremity PAD diagnosis in patients with suspected PAD, including those with nonhealing wounds, age ≥65 years, or age ≥50 years with history of smoking or diabetes 7
ABI should be measured in both legs in all new patients with PAD of any severity to confirm diagnosis and establish a baseline, according to the American Heart Association 6
ABI results should be uniformly reported with noncompressible values defined as >1.40, normal values 1.00-1.40, borderline 0.91-0.99, and abnormal ≤0.90, as recommended by the American College of Cardiology 7

The American Heart Association recommends using the toe-brachial index to establish lower extremity PAD diagnosis in patients with suspected PAD but in whom ABI test is not reliable due to noncompressible vessels (usually patients with long-standing diabetes or advanced age) 6

The American Heart Association suggests that leg segmental pressure measurements are useful to establish lower extremity PAD diagnosis when anatomic localization is required to create a therapeutic plan 6