To examine the feasibility of using pulsatility index-adjusted (PI) flow equations to accurately characterize blood volume flow changes using Doppler technique in patients with peripheral artery disease (PAD) before and after percutaneous transluminal angioplasty (PTA).
PTA was performed on 17 PAD patients (23 target vessels treated, 16 anterior tibial arteries and 7 posterior tibial arteries). Arterial diameter, peak systolic velocity, PI, time-averaged mean velocity, and measured volume flow (MVF) of dorsalis pedis artery (DPA) and common plantar artery (CPA) were measured with duplex Doppler ultrasound before and after PTA. PI-adjusted volume flows (PIVF) were calculated as part of the MVF/PIVF relative percentage metric.
Significant changes (p<0.001) of the MVF (mean: 33.0 ml/min, range: -20.9 to 102.2 ml/min ) and MVF/PIVF relative percentages (mean: 51.8, range: 5.1 - 127.2%) in the DPA existed between before and after PTA, whereas no significant changes could be found in the CPA (mean:10.9 ml/min, p=0.148 and mean: 21.3%, p=0.146, respectively). Of the 7 treated posterior tibial arteries, the increments of the MVF/PIVF (mean: 60.4%, p=0.033) was significant but not in the MVF (mean: 26.5 ml/min, p=0.125). The ABI also showed non-significant changes (p=0.081). All PI-adjusted results matched clinical observations after blood flow restoration.
No conclusions can be drawn from the comparison of actual measured volume flow between before and after PTA. However, using the MVF/PIVF relative percentage allows for a more objective framework upon which to base clinical observations and provides clarity in situations where direct measurement provides a counter-intuitive or contradictory picture.