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Ultrasonic plaque character and outcome after lower limb angioplasty
G Ramaswami1, T Tegos, A N Nicolaides
1Irvine Laboratory for Cardiovascular Investigation and Research, Academic Surgical Unit, Imperial College School of Medicine at St. Mary's, the Department of Radiology, St. Mary's Hospital, London, United Kingdom.
Insights
Ultrasonic plaque echodensity can predict restenosis after angioplasty. Lower echodensity plaques are associated with better outcomes, identifying high-risk patients for improved procedural selection.
Area of Science:
- Vascular Surgery
- Diagnostic Imaging
- Interventional Cardiology
Background:
- Percutaneous transluminal angioplasty (PTA) is a common procedure for treating arterial stenosis.
- Restenosis remains a significant complication after PTA, impacting long-term outcomes.
- Identifying patients at high risk for restenosis is crucial for optimizing treatment strategies.
Purpose of the Study:
- To investigate the utility of ultrasonic plaque characteristics, specifically plaque echodensity, in predicting restenosis after PTA.
- To determine if plaque echodensity can identify patients at high risk of restenosis.
Main Methods:
- Duplex ultrasound scanning was used to analyze 31 arterial stenoses in 17 patients before and after PTA.
- B-mode images were digitized, and plaque echodensity was quantified using the gray-scale median (GSM).
- Restenosis was defined as an increase in peak systolic velocity ratio (PSVR) > 2 post-PTA, with follow-up up to 1 year.
Main Results:
- Stenoses with a GSM < 25 showed a significantly greater reduction in plaque thickness post-PTA compared to those with GSM > 25.
- The restenosis rate was significantly lower (11%) for lesions with GSM < 25 versus 78% for lesions with GSM > 25 (P <.001).
- A GSM < 25 identified a subgroup of patients with a low prevalence of restenosis.
Conclusions:
- Plaque echodensity, measured by GSM, is a valuable parameter for evaluating stenoses before PTA.
- Ultrasonic assessment of plaque echodensity can predict initial procedural success and identify patients at high risk of restenosis.
- Identifying high-risk restenosis patients can improve patient selection for PTA and inform future studies on restenosis prevention.
Purpose:
The value of ultrasonic plaque characteristics in identifying patients at "high-risk" of restenosis after percutaneous transluminal angioplasty (PTA) was studied.
Methods:
Thirty-one arterial stenoses (6 common iliac, 2 external iliac, 1 profunda femoris, 21 superficial femoral, and 1 popliteal) in 17 patients who underwent angioplasty were studied by means of duplex scanning. With a computer-based program, B-mode images were digitized and normalized using 2 reference points, blood and adventitia. A grey level of 0 to 5 was allocated for the lumen (blood) and 180 to 190 for the adventitia on a linear gray scale of 0 to 255 (0 = absolutely black; 255 = absolutely white), and the overall plaque gray-scale median (GSM) of the pixels of the plaque was used as a measure of plaque echodensity. After PTA, follow-up of stenoses was done on day 1, weekly for 8 weeks, at 3 months, 6 months, and 1 year. The total plaque thickness (sum of anterior and posterior components), minimal luminal diameter (MLD), and peak systolic velocity ratio (PSVR) were measured for all stenoses. An increase of more than 2 in the PSVR was the duplex criterion used to signify restenosis.
Results:
The GSM of the stenoses before angioplasty ranged from 6 to 71 (mean, 31.3 +/- 17.9); 17 stenoses had a GSM less than 25 (mean, 18.7 +/- 5.3), and 14 had a GSM more than 25 (mean, 46.4 +/- 15.8). When the GSM was less than 25, the absolute reduction in plaque thickness on day 1 post-PTA was 3.3 +/- 1.8 mm, in contrast to 1.8 +/- 1.6 mm when GSM was more than 25 (P <.03). The restenosis rate (PSVR more than 2) was 41% at 6 months and remained unchanged at 1 year. When the GSM was less than 25, restenosis occurred in 11% of lesions, in comparison with 78% when the GSM was more than 25 (P <.001).
Conclusion:
Plaque echodensity can be used to evaluate stenoses before PTA, to predict initial success and identify a subgroup that has a high prevalence of restenosis. The identification of a group at "high-risk" of restenosis can improve the selection of patients for the procedure and also be used in prospective studies on the prevention of restenosis.