Revascularization (Graft-PTA)

Peripheral Arterial Grafts or Angioplasty (PTA) Site

1. Normal

a. Peak systolic velocities (PSV) ≥45 cm/sec 

b. No focal increase in PSV, velocity ratio (VR) <2 noted from segment to segment and waveform patterns remain consistent along the graft.

2. Abnormal: Risk stratification for graft thrombosis based on surveillance data

Velocity Ratio: PSV in stenosis compared to PSV in proximal contiguous segment

Graft flow velocity (GFV), low flow states, may be global or distal

Risk Stratification:

a) Generally, intermediate risk is 50-74% stenosis: VR >2 and PSV 180-300 cm/sec   

b) Generally, high risk is >75% stenosis: VR >3.5 and PSV >300 cm/sec

c) Generally, highest risk is >75% stenosis: VR >3.5 and PSV >300 cm/sec and GFV <45 cm/sec

NOTE:  Diameter changes / mismatches between the inflow artery and graft or the graft and outflow artery may also result in velocity changes that are not related to stenosis. Vessel angulations at the proximal or distal anastomosis can also influence velocity estimations and produce turbulence.