Can Post-thrombotic Syndrome Be Prevented?

The case for mechanical thrombectomy as a means to eliminate post-thrombotic syndrome (PTS) was discussed today by Manuela Konert, a consultant interventionalist and head of the venous centre at University Hospital Leipzig, Germany. 

PTS arises between 6 months and 5 years after a deep vein thrombosis (DVT). The current guidelines state that anticoagulation is the treatment for DVT, noted Dr Konert. “Even then we see up to 50% of patients develop PTS after a DVT,” she told LINC Today.

The fact is that DVT is quite a common disease, in turn meaning that many young people are seen with PTS. However, modern approaches—based on mechanical devices—may prevent that. “With the new treatment options we have right now, I think we can lower the PTS rate,” continued Dr Konert.

Traditionally, the only alternative to anticoagulation has been lysis or thrombolytic therapy, but lysis comes with elevated bleeding risk (lysis research includes the ATTRACT¹ and CaVenT trials²). However, Dr Konert showed research that suggests that new mechanical thrombectomy devices are safer than lysis.

“We don’t need lysis—we can treat patients safely with mechanical thrombectomy, and right after the diagnosis of DVT,” she said. “It is very beneficial for patients to be able to remove the whole clot at once.”

Until now, mechanical thrombectomy remains underused by many physicians, said Dr Konert, most likely because they are unaware of new options. In young people in particular, there is a reluctance to use anything other than anticoagulation. “Many physicians would prefer to risk (and then treat) PTS, rather than potentially cause a stroke in a patient via intracranial bleeding,” she said. “But now we have to think differently. We have a safer device, one which won’t cause bleeding or require an ICU. Now we can actually prevent PTS.”

Dr Konert outlined the growing research into mechanical options. One of the most important is the CLOUT registry³—a prospective, single-arm study evaluating outcomes of all-comer patients with proximal lower-extremity DVT after thrombectomy with the ClotTriever system (Inari Medical). The registry features a large cohort of over 500 patients from all over the US, and good data on safety and reduction of PTS has already been released, commented Dr Konert, showing zero bleeding risk.

The eagerly awaited DEFIANCE trial⁴ is also focusing on the ClotTriever system. A prospective, multicenter, randomized controlled trial, DEFIANCE is studying vessel patency (ClotTriever intervention arm) versus conservative medical management using anticoagulation therapy alone (conservative medical management arm) in the treatment of subjects with symptomatic unilateral iliofemoral DVT. The study will collect data on demographics, comorbidities, details from DVT diagnosis and treatment, and clinical outcomes through to a 6-month follow-up visit. “This could change the guidelines,” stressed Dr Konert.

Before DEFIANCE reports, what’s important now is to get the message across to physicians about mechanical options, Dr Konert underlined. “We have to actually inform physicians that, especially with younger people who are healthier, they have a good chance with mechanical thrombectomy because it’s quite a safe procedure,” she said.

Today at LINC, beyond the use of mechanical thrombectomy devices for the iliac veins, Dr Konert also talked about an area that is even more controversial: treating the femoral vein to reduce PTS. “Usually you don’t treat the femoral vein, but I think it does need attention in avoiding PTS,” she said. Studies in this area are extremely limited. For example, a subgroup analysis within the ATTRACT trial has not shown good results, noted Dr Konert. “I think this is quite an empty field. We need to start research, and this new trial is more like a starting gun.”

In conclusion, Dr Konert reiterated that new interventional methods for treating DVT are safe, and can avoid PTS. With an eye on rewriting the guidelines, Dr Konert also re-emphasized that treating the femoral vein could be quite important. “We need to be intrepid with venous interventions. It’s all quite new, so we all need to navigate what’s possible, gather data and pool our experience.”

References

1. Vedantham S, Goldhaber SZ, Julian JA, et al. pharmacomechanical catheter-directed thrombolysis for deep-vein thrombosis. N Engl J Med. 2017;377(23):2240–2252.

2. Enden T, Haig Y, Kløw NE, et al. Long-term outcome after additional catheter-directed thrombolysis versus standard treatment for acute iliofemoral deep vein thrombosis (the CaVenT study): a randomized controlled trial. Lancet. 2012;379(9810):31–38.

3. Shaikh A, Zybulewski A, Paulisin J, et al. Six-month outcomes of mechanical thrombectomy for treating deep vein thrombosis: analysis from the 500-patient CLOUT registry. Cardiovasc Intervent Radiol. 2023;46(11):1571–1580.

4. DEFIANCE: RCT of ClotTriever System Versus Anticoagulation In Deep Vein Thrombosis (DEFIANCE). ClinicalTrials.gov. Available at: https://classic.clinicaltrials.