What’s new in Interventional Radiology – November 2020

4 years ago

Correlation between Post-Procedure Residual Thrombus and Clinical Outcome in Deep Vein Thrombosis Patients Receiving Pharmacomechanical Thrombolysis in a Multicenter Randomized Trial

Mahmood K. Razavi, MD, Amber Salter, PhD, Samuel Z. Goldhaber, MD, Samantha Lancia, MSc, Susan R. Kahn, MD, MSc, Ido Weinberg, MD, Clive Kearon, MB, PhD, Ezana M. Azene, MD, PhD, Nilesh H. Patel, MD, and Suresh Vedantham, MD

J Vasc Interv Radiol 2020; 31:1517–1528

Published: September 15, 2020

DOI: https://doi.org/10.1016/j.jvir.2020.07.010

Post-thrombotic syndrome (PTS) occurs in 40-50% of patients with proximal deep vein thrombosis (DVT). Catheter-directed thrombolysis (CDT) for DVT has been largely predicated on the “open vein hypothesis” which hypothesizes that early thrombus removal might facilitate long-term venous patency, reduce PTS and improve quality of life.

This study aims to find a correlation between the amount of residual thrombus on the immediate post pharmacomechanical catheter-directed thrombolysis (PCDT) venogram and the patient’s clinical outcome, notably their incidence of PTS.

It is part of the ATTRACT trial, a phase III, multicenter, open-label, assessor-blinded, randomized clinical trial. 317 participants  (200 iliofemoral DVT and 117 femoral–popliteal DVT) were enrolled at 56 clinical centers in the United States. Patients had venograms before and then immediately after PCDT. PCDT was performed with an rt-PA infusion and, in certain cases, with Trellis-8 or AngioJet devices. The physician operators recorded their visual assessments of thrombus regression and venous flow. Residual thrombus was also assessed by independent readers using a modified Marder scale. These immediate postprocedure results were correlated with patient outcomes at 1, 12, and 24 months. Factors that were considered were residual thrombus on duplex ultrasound, the presence and severity of PTS and the patient’s quality of life.

This study demonstrated that PCDT successfully removes thrombus in acute proximal DVT (96% and 84% of patients having 50% and 90% thrombus removal, respectively). Post PCDT, spontaneous venous flow was present in 99% of iliofemoral venous segments and in 89% of femoral–popliteal venous segments.  Unfortunately, the immediate post-PCDT residual thrombus volume was not associated with less frequent PTS. There was no statistically significant improved clinical outcome or valvular reflux. However, for iliofemoral DVTs, a lower residual thrombus volume was associated with a reduced 24-month PTS severity, with a moderate to severe PTS incidence of 8% in patients with complete lysis vs. 19% in patients with residual thrombus.

It questions the validity of the “open vein hypothesis” and encourages future research to understand the pathogenesis of PTS, with particular attention to how patency can be maintained over time.

The authors also state that clinicians should not suggest to patients that thrombus removal will prevent PTS, and that PCDT for femoral–popliteal DVT should be rare.


Evaluation of the Benefit of Extended Catheter-Directed Thrombolysis with Serial Angiography for Acute Pulmonary Embolism

Assaf Graif, MD, Keval D. Patel, DO, MS, Neil J. Wimmer, MD, MS, George Kimbiris, MD, FSIR, Christopher J. Grilli, DO, and Daniel A. Leung, MD, FSIR

Published: October 19, 2020

J Vasc Interv Radiol 2020; 1–10

DOI: https://doi.org/10.1016/j.jvir.2020.08.004

Pulmonary artery catheter-directed thrombolysis (CDT) is a treatment option for massive and submassive acute pulmonary embolisms (PE). Residual pulmonary artery thrombus result in worse long-term outcomes and recurrent thromboembolic events.

This study aims to determine if repeat visits to the angiography suite for extension of CDT is beneficial for the treatment of acutke PE.

This is a retrospective cohort study that took place between 2009 and 2019 with patients of a single community hospital system. The study analyses the clinical outcomes of 156 patients who presented with a massive or submassive PE within 14 days of symptom onset and underwent pulmonary artery CDT with the recombinant tissue plasminogen activator (rTPA) alteplase and at least 1 follow-up visit to the angiography suite after the initial CDT. 111 treatments were terminated after a single follow-up visit to the angiography suite and 45 treatments were continued to additional follow-up visits (2 follow-up visits in 40 cases and 3 follow-up visits in 5 cases).  An initial PAP measurement, pulmonary angiography and CDT was performed. All patients then returned to the angiography suite after a mean of 19.4 hours ± 5.1 for repeat PAP measurements and pulmonary angiography to assess residual thrombus according to the Miller PE severity index. This was followed by a decision to continue or conclude CDT.

Patients who had CDT extended beyond the first follow-up visit required a higher total dose of tPa (40.7 mg ± 14.3 vs 22.6 mg ± 9.9, P < .001) to achieve a similar final Miller score and a similar reduction in systolic PAP (14.4 mm Hg ± 10.2 vs 12.6 mm Hg ± 11.9, P =.6). The systolic PAP and heart rate were significantly higher in the multiple follow-up group during the initial and first follow-up visits. Both groups demonstrated a significant decrease in systolic PAP between the initial procedure and subsequent follow-ups.

While it may be unnecessary to bring all patients back for a follow-up visit, threshold values of systolic PAP > 55 mm Hg and heart rate > 100 beats/ min during the initial CDT may benefit from extended CDT to achieve similar improvements in systolic PAP and thrombus burden. Additional follow-up visits and extended CDT did not result in higher complication rates (hemorrhage) in this cohort, although a larger study is required to validate these findings given the small cohort for the multiple follow-up group.


First-in-Human Study with Eight Patients Using an Absorbable Vena Cava Filter for the Prevention of Pulmonary Embolism

Guillermo Elizondo, MD, Mitchell Eggers, PhD, MBA, Mario Falcon, MD, Miguel Trevino, MD, Roberto Marrufo, MD, Carlos Perez, MD, Edgar Nunez, MD, Rudy Moreno, BS, Alexis Mitchell, PhD, Audrey Sheppard, BS, Stephen Dria, MS, Turner Jay, BS, Ray Kirk, MD, David Hovsepian, MD, and Joseph Steele, MD

Published: September 29, 2020

J Vasc Interv Radiol 2020

DOI: https://doi.org/10.1016/j.jvir.2020.07.021

Patients with deep venous thrombosis (DVT) and a contraindication to, or failure of, anticoagulating agents may benefit from inferior vena cava (IVC) filter insertion to prevent pulmonary embolisms (PE). However, there are associated adverse events with conventional metal IVC filters such as migration, fracture, embolization, and organ perforation which increase with indwelling time. Therefore, retrieval within weeks of deployment is often recommended, however the rate varies between institutions.

This is a first-in-human study which prospectively evaluates absorbable vena cava filters. 8 patients were enrolled  over a period of 36 weeks (December 2018 to April 2019). There is a single treatment site and patient race, and nearly all female participants (78%). Patients either had a proven DVT or PE and a contraindication to, or failure of, anticoagulant treatment, or  required transient (5 wk) venous thromboembolism (VTE) prophylaxis due to elevated VTE risk and contraindications to anticoagulation agents. The protocol excluded patients with IVC diameters smaller than 16 mm.

The absorbable filter set contains an absorbable polymer filter preloaded within a delivery system over a 33-mm diameter semi-compliant balloon. Six radiopaque markers are attached to the filter. The polymer filament is polydioxanone known to safely breakdown within approximately 6 months. Once the resorbable IVC filters were deployed, follow-up visits were scheduled at 5 weeks (±1 wk) to assess PE and filter stent endothelialization, 11 weeks (±1 wk) to ensure absence of thrombus before filter basket disintegration, and 36 weeks (±2 wk) to compare the IVC before filter deployment and after filter resorption. Subjects underwent computed tomographic (CT) and abdominal radiography before filter implantation and 5, 11, and 36 weeks afterward to assess filter complications. Possible PE was assessed with CT angiography before and 5 weeks after filter placement.

The ease of deployment was similar to that of conventional endovascular device deployments. There were no post-procedural complications or adverse effects after 36 weeks of follow up. 2 patients were lost to follow-up before the final 36-week.

Despite the small sample in the present early feasibility study, this initial experience with the absorbable filter in humans had a 100% clinical success rate. More research in this field is required as the size is insufficiently powered to evaluate filter effectiveness.


Evaluation and Management of Intermediate and High-Risk Pulmonary Embolism

Ramsey Al-Hakim, Ningcheng Li, Stephanie Nonas, Bishoy Zakhary, Brandon Maughan, Ryan Schenning, Khashayar Farsad, and John A. Kaufman

Published: March 2020

American Journal of Roentgenology 2020 214:3, 671-678

DOI: https://doi.org/10.2214/AJR.19.21861

Pulmonary embolisms (PE) are linked to long-term sequelae.  Some examples include thromboembolic pulmonary hypertension (CTEPH) and post PE syndrome which encompasses decreased exercise tolerability and quality of life.

This evidence-based review aims to overview PE treatment options to reduce PE mortality, notably in intermediate- and high-risk PEs. The two major guidelines that are reviewed are the 2014 European Society of Cardiology (ESC) guidelines on the diagnosis and management of acute PE and the 2016 Antithrombotic Therapy for Venous Thromboembolic Disease CHEST guideline.

This article emphasizes the importance of initial PE classification. The terms “massive” and “submassive” are considered too broad and confusing by the authors, as they solely refer to the clinical implications of the PE without radiological consideration. They favor the ESC classification system which grades a PE as high risk if associated with hypotension (<90 mmHg systolic blood pressure for >15 minutes) ; intermediate-high risk if associated with both imaging and cardiac biomarker evidence of RV dysfunction without hypotension; intermediate-low risk if associated with either imaging or cardiac biomarker evidence of RV dysfunction without hypotension; and low risk if associated with none of those findings. RV dysfunction is defined as an RV/LV diameter ratio greater than 0.9 on CT or evidence of RV dysfunction on echocardiography.

According to the 2014 ESC guidelines, patients with high or intermediate clinical probability of PE should be initiated on parenteral anticoagulation while workup is in progress (Class I, Level C). For intermediate-risk PEs,  systemic thrombolytic therapy can be considered if there is hemodynamic or cardiopulmonary instability. Percutaneous catheter-directed treatment or surgical pulmonary embolectomy may be considered if hemodynamic decompensation appears imminent and the anticipated bleeding risk with systemic thrombolysis is high. For high-risk PEs,  patients should be promptly evaluated for systemic thrombolysis. If systemic thrombolysis presents high risk, is contraindicated, or has failed, catheter-assisted thrombus removal (with or without catheter-directed thrombolysis) or surgical embolectomy should be considered. IVC filter placement should be decided on an individualized basis. The 2014 ESC guidelines recommend IVC filter placement when there are absolute contraindications to anticoagulation and in cases of recurrent PE despite therapeutic levels of anticoagulation.  The 2011 American Heart Association guidelines state that IVC filter placement may be considered for patients with acute PE and very poor cardiopulmonary reserve, including those with massive PE.

Further research is required to learn about the risks and benefits of  catheter-directed thrombus removal methods (mechanical with or without catheter-directed thrombolysis) and IVC filter placement for intermediate- and high-risk PE.


Acute aorto-iliac occlusion in patient with COVID-19

Iris Naudin, Anne Long, Christophe Michel, Bertrand Devigne, Antoine Millon, Nellie Della-Schiava

Publication: October 16, 2020

Journal of Vascular Surgery – Journal Pre-proof

DOI: https://doi.org/10.1016/j.jvs.2020.10.018

The COVID-19 pandemic has affected almost every country. It is known for it’s respiratory symptoms however its proinflammatory state also has repercussions on multiple organs.

This is a case report of an acute aorto-iliac and lower limb artery occlusions in a patient with severe COVID-19 infection.

The patient is a 56 year old male who had diabetes, hypertension and obesity. He presented with acute muscle weakness and sensory loss of the left lower limb. A thoraco-abdomino-pelvic computed tomography (CT) was done and showed distal aorta and left iliac artery occlusions. A small thrombus was found floating in the aortic arch. There were also typical COVID-19 pulmonary findings, and despite a negative throat swab, the patient was considered COVID-19 positive.

He was taken to surgery where percutaneous right common femoral and open left common femoral approaches were performed. Covered kissing stents were placed and a completion arteriography showed left popliteal occlusion which was treated by open popliteal thrombectomy. Thirteen minutes later, he showed signs of acute right limb ischemia and a right open femoral approach was performed. The arteriography of the right lower limb showed popliteal and distal leg artery thrombosis. A new complete right below-the-knee thrombectomy was performed.  A few hours later, the patient presented with a new episode of right lower limb ischemia and signs of irreversible ischemia in the left foot. CT scan showed satisfactory aorto-iliac revascularization and a new thrombosis of the right popliteal artery extending to distal arteries. There was also a new occlusion of the deep left femoral artery and no patent artery below the left ankle. A second right popliteal artery thrombectomy was performed. The patient was this time diagnosed with COVID-19 by PCR-positive throat-swab. A third CT scan was performed for hemodynamic instability which demonstrated that the  aorto-iliac kissing stents and right popliteal artery were patent, but there was a new small right renal infarction.  A left trans-tibial amputation was decided after hemodynamic stabilization.  The last CT scan performed on May 1, 2020 to control vascular revascularization showed complete lysis of the thoracic aorta’s thrombus.

The mechanism of the occlusion is thought to be embolization from a floating thrombus in the aortic arch caused by the viral infection.  There was a systemic inflammatory response syndrome caused by the virus. This induced a hypercoagulable state and an endothelial dysfunction. Anticoagulation was the treatment of choice, as the author’s wanted to avoid possible embolization from endovascular exclusion of the thrombus.

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