Early (2 Week) Post-operative Ultrasound to Predict Outcome, Guide Re-intervention, and Tailor Surveillance in Patients Undergoing Deep Venous Stenting for Post Thrombotic Syndrome

Wednesday, September 20, 2023

11:28 AM – 11:38 AM US EDT

Location: Grand Ballroom A

Introduction, Objectives, and/or Purpose: Close post operative ultrasound surveillance underpins our approach to maintaining inferior vena cava and iliofemoral venous stent patency. It is assessed using duplex ultrasonography at 24 hours, 2 weeks, 6 weeks, 3 months, 6 months, 1 year and yearly post intervention. There is, however, limited data on the optimal interval and duration of ultrasound surveillance following deep venous intervention. This practice is both time and resource intensive, can be burdensome for patients and can overwhelm a growing venous practice. This study aimed to determine if the 2-week surveillance ultrasound could predict longer-term patency, reintervention, and help rationalize post-operative surveillance.

Methods: Two-week surveillance scans were analysed for all patients undergoing deep venous stenting between 2014-2023. Patients with post thrombotic syndrome (PTS) were identified for further analysis. Patients with non-thrombotic iliac vein lesions (NIVL) and other indications for stenting were excluded. The maximal in-stent restenosis (ISR) was calculated, and patients were categorized as high (>50%), moderate (30-50%) or low ( <30%) ISR. Standard early practice involved reintervention when ISR was >50%, but later was offered only if patients were also symptomatic. Frequency distribution of primary reintervention was analyzed along with scan to intervention interval. Intervention occurring within 14 days of ultrasound was classed as surveillance driven. Kaplan-Meier analysis was carried out for primary, primary-assisted, and secondary (cumulative) patency. Survival curves were analyzed using the log-rank test to calculate hazard ratios (HR) and 95% confidence intervals (95%CI). Cox regression was performed to assess the relationship between degree of ISR at 2-weeks on primary and secondary patency.

Results: In total, 515 limbs of 421 patients (59.86% female, n=252) underwent deep venous stenting during the study period. Post thrombotic syndrome was the indication for stenting in 348 patients (82.7%). The patients that were excluded were comprised of NIVL (n=66, 15.7%) and other non-PTS (n=7, 1.7%). The PTS group consisted of 150 male and 198 female patients, totalling 432 limbs (264 unilateral and 84 bilateral). Cumulative patency at one, two and 5 years was 94.1%, 92.0% and 82.03% respectively. Two-week scans were available for 341/432 limbs (78.9%), 39/432 (9.02%) had undergone re-intervention or occluded prior to the two-week scan and 51/432 (11.8%) were scanned later. The two-week scans revealed 184 limbs with low, 65 with moderate and 92 with high ISR. Loss of patency occurred in 204 limbs, of which 198 underwent reintervention. Most reinterventions occurred within 8 weeks (54.41%), the median scan to reintervention interval was 8 days (IQR 4-28 days), 131/198 (66.1%) were classed as surveillance driven reinterventions. There was a statistically significant difference in primary patency between the low and moderate ISR groups (log-rank 2=9.689, p=0.0019) with a hazard ratio of 2.090 (95%CI 1.20-3.64) for patency loss (Figure 1). The secondary patency was significantly reduced in the high ISR group, HR 4.664 (95%CI 2.204-9.870, p<0.0001) when compared to low and moderate (Figure 2). Cox’s proportional hazard regression indicated that degree of ISR at two-weeks was a predictor for primary (p=0.0025) and secondary patency (p < 0.0001).

Conclusion(s): Reinterventions occur early for patients undergoing deep venous stenting for PTS. The majority of these are driven by post operative surveillance. The two-week surveillance scan appears to predict primary patency in these patients. Patients with moderate ISR (30-50%) at two-weeks have poorer primary patency than the low ISR group but secondary patency is comparable. This suggests they may benefit most from close surveillance and early re-intervention. A high degree of ISR at two-weeks (>50%) is associated with poorer long-term outcomes despite efforts to maintain patency with reintervention. There may be additional factors in this cohort that account for this, but they have not been identified in this study. Further work is required to establish an optimal post-operative surveillance schedule. These data suggest that the degree of ISR at two-weeks may be an early signal of longer-term outcomes and may be useful in stratifying patients to tailored surveillance. This could potentially free up considerable resources and allow it to be diverted to where it is most needed.

Presenting Author(s)

Ehsanul K. Choudhury, MBBS, BSc(Hons), MRCS

Vascular Surgery Registrar & Clinical Research Fellow
Academic Department of Vascular Surgery, St. Thomas' Hospital, London UK
London, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.

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Co-Author(s)

Adam M. Gwozdz, MD PhD

Clinical Lecturer in Vascular Surgery
Imperial College London
Imperial College London
London, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose. or AVLS has reviewed / mitigated there are no relevant financial relationships with ineligible companies.

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NT

Narayanan Thulasidasan, MBBS, FRCR

Consultant Interventional Radiologist
Department of Radiology, St. Thomas' Hospital, London, UK
London, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.
NK

Narayan Karunanithy, MBBS, FRCR, FCIRSE

Consultant Interventional Radiologist
Department of Radiology, St. Thomas' Hospital, London, UK, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.
RM

Rachael I. Morris, MBBS

Doctor
King's College London, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.
SP

Soundrie Padayachee, PhD

Clinical Scientist
Department of Radiology, St. Thomas' Hospital, London, UK, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.
PS

Prakash Saha, MBBS, PhD, FRCS

Consultant Vascular Surgeon
Academic Department of Vascular Surgery, St. Thomas' Hospital, London UK, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.
BN

Bhavesh Natha, MBChB, FCS (SA)

Consultant Vascular Surgeon
Academic Department of Vascular Surgery, St. Thomas' Hospital, London UK, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.
TK

Taha Khan, MD, FRCS

Consultant Vascular Surgeon
Academic Department of Vascular Surgery, St. Thomas' Hospital, London UK, England, United Kingdom

Disclosure(s):
The forementioned Program Planner, Faculty, Author, Moderator, or Speaker, has declared for this educational activity, having no relevant financial relationship(s) with ineligible companies to disclose.
Stephen Black, MD

Vascular Surgeon and Professor of Venous Surgery
Kings College London and Guy’s and St Thomas’ Hospital
Kings College London
London, England, United Kingdom

Disclosure(s): BSCI: Consultant/Advisory Board, Other Research Support, Research Grant; Gore: Consultant/Advisory Board; Medtronic: Consultant/Advisory Board, Other Research Support; Phillips: Consultant/Advisory Board, Other Research Support