Pitfalls of ABI In critical limb ischemia Gholam

Pitfalls of ABI In critical limb ischemia Gholam Ali, MD, FACC, FSVM, RPVI, FASH, FSCCT, ABCL Assistant Professor of Medicine and Radiology Medical Director Vascular Lab( ICAVL) School of Medicine Tulane University

I have no financial disclosures related to this presentation

Outline • Definition of ABI • DATA of ABI used in Diagnosis vs Prognosis. – Traditional ABI vs. Alternative ABI. • Role of Dynamic ABI – Exercise ABI – Dorsiflexion ABI

ABI/TBI • • 0. 91 - 1. 30 Normal 0. 70 - 0. 90 Mild disease 0. 40 - 0. 69 Moderate disease 0. 00 - 0. 39 Severe disease • ABI >1. 3 is abnormal and consistent with calcified vessels - unreliable • ABI alone is inadequate to assess distal perfusion • TBI ≥ 0. 7 is normal Newman AB, et al. Circulation. 1993; 88: 837 -845.

Wound healing and non invasive tests 1. 2. 3. 4. ABI [PT &DP] PSP > 50 mm Hg TBI [Toe] PSP > 50 mm Hg TCPO 2 > 70 mm Hg Skin Perfusion Pressure > 50 mm Hg

Critical Limb Ischemia DP INDEX 0. 36 “NORMAL ABI” with Traditional Measurement

Critical Limb Ischemia PT INDEX 0. 6 “NORMAL ABI” with Traditional Measurement

Proximal Arterial Stenosis 194 cm/s 91 cm/s Right Common Femoral Artery Severe Stenosis 95 cm/s 149 cm/s Left Common Femoral Artery Moderate Stenosis Both traditional and alternative ABI are normal

Recommendations for the Calculation of the ABI 1. When ABI is used as a diagnostic tool to assess patients with symptoms of PAD, the ABI should be reported separately for each leg (Class I; Level of Evidence C). 2. When the ABI is used as a prognostic marker of cardiovascular events and mortality, the lower of the ABIs of the left and right leg should be used as the prognostic marker of cardiovascular events and mortality. The exception to this recommendation is the case of non-compressible arteries (Class I; Level of Evidence C).

External Iliac Endofibrosis *If rest ABI is normal, then must perform exercise ABI to unmask disease

Popliteal Artery Entrapment Syndrome (PAES) >30% reduction in ABI with exercise

Cystic Adventitial Disease: MRI and Angiography (right leg) Identification with abnormal ABI with exercise

To avoid this scenario…

Traditional vs Alternative ABI Nead KT, J Am Coll Cardiol. 2013 Aug 6; 62(6): 553– 559

Take Home Message 1. Traditional ABI (using higher values of PT/DP) if utilizing for diagnosis 2. Alternative ABI (using lower value of PT/DP) if utilizing for treatment 3. Exercise ABI for diagnosis of proximal stenosis/external iliac Endofibrosis 4. ABI with exercise for popliteal artery entrapment and cystic adventitial disease (30% reduction in ABI post-exercise) 5. Highlight need for non-invasive lab to report all measured indices 6. Our current practice at Tulane University Medical Center: Right ABI—PT index with PSP, DP index with PSP Left ABI—PT index with PSP, DP index with PSP 7. If normal, exercise ABI

Thank You gali 1@tulane. edu Thanks to Tulane Cardiology Fellows: Drs. Abdallah and Moscona