###### Abstract  
Background: Residual stenosis and dissections occurring after femoro-popilteal percutaneous transluminal angioplasty (PTA) can compromise vessel patency and should therefore be properly dealt with at the time of the index procedure. Sometimes, the decision to optimize the PTA result may be challenging because it is based on evidence from angiography which, as a bi-dimensional imaging technique, has well-known limitations. Objectives: The objective of this study was to evaluate whether an intraoperative Doppler ultrasound (DUS) assessment of femoro-popilteal lesions that have undergone PTA allows for a more accurate definition of technical success compared to angiography. This was assessed through the identification of those lesions that, despite fulfilling angiographic criteria for technical success, have a functional relevance at DUS. Methods: In this cross-sectional study, data from 62 patients who had undergone femoro-popilteal PTA and intraoperative DUS were retrieved. The procedures were performed at two referral hospitals for peripheral interventions between 2018 and 2019. The selected patients had 48 residual stenoses in the range of 40-50% and 14 grade-C dissections. Results: The mean lesion length was 211 \(\pm\) 85.2. Angiography-based and DUS-based technical success matched 41 lesions (66%). The remaining 21 lesions, which had abnormal DUS, were successfully optimized by post-dilatation or stenting in 19 cases. Finally, after PTA optimization, DUS-based and angiography-based technical success matched 95% of cases. Conclusions: An intraoperative DUS assessment of intermediate residual stenosis or grade C dissections occurring after PTA of long femoro-popilteal arteries allowed for a more accurate definition of technical success than angiography and guided a further PTA optimization in one-third of the cases.  
P 2025 15 2619 2025 15 2619 2025 15 2619 2025 15 2619 2025 15 2619 2025 15 2619 2025 15 2619 2025 15 2619 2025 15 2619 2024 2025 2024 Condensed Abstract  
Residual stenosis and dissections occurring after femoro-popiletal percutaneous transluminal angioplasty (PTA) can compromise PTA patency and should therefore be fixed at the time of the index procedure. However, the decision to optimize the PTA may be challenging since it is based on angiography, which has well-known limitations. We investigated whether the assessment of residual stenosis and dissections by intraoperative Doppler ultrasound (DUS) allows for a more accurate definition of technical success after long femoro-popiletal PTA compared to angiography. One-third of the lesions assessed by DUS showed abnormal PSVR and were optimized by post-dilatation or stenting. Following this, the integrated technical success, fulfilling both angiographic and DUS-based criteria, increased from 66% to 95%. In conclusion, compared to angiography, an intraoperative DUS assessment of intermediate residual stenosis or grade C dissections allowed for an accurate definition of technical success and guided PTA optimization in 33% of cases.  
Clinical Perspective  
What is known? A suboptimal result percutaneous transluminal angioplasty might compromise vessel patency and should therefore be properly optimized at the time of the index procedure. However, in the case of borderline residual stenosis or long dissections, the identification of those lesions that would benefit from further optimization may be very challenging since identification is based on angiography, which has well-known limitations.  
What is new? An intraoperative DUS assessment, complementary to the angiography, allowed for the identification of a significant proportion of residual stenoses or long dissections that, despite fulfilling the angiographic criteria for technical success, underwent PTA optimization based on their abnormal DUS.  
What is next? The next step is to assess whether this approach, characterized by a DUS-guided optimization of long SFA PTA, can improve the long-term primary patency as compared to the standard of care in larger prospective studies.