‘Less ominous’ short-term, long-term outcomes with isolated vs. proximal DVT
Click Here to Manage Email Alerts
Adults with isolated distal deep vein thrombosis experience fewer short- and long-term adverse outcomes compared with those with proximal DVT, including major bleeding and venous thromboembolism deterioration, data show.
In an analysis of registry data, researchers also found that one in every 22 patients with isolated distal DVT had recurrent VTE at 1-year follow-up; more than 45% had some form of signs or symptoms of post-thrombotic syndrome.
“There are two take-home messages. First, that distal DVT has less ominous outcomes compared with proximal DVT, likely as a result of differences in patient factors/comorbidities but also the location of the clot itself,” Behnood Bikdeli, MD, MS, instructor in medicine at Harvard Medical School and an associate physician at the division of cardiovascular medicine at Brigham and Women’s Hospital, told Healio. “Second and equally important, we show that isolated distal DVT is not entirely benign, and our results should not give a false sense of reassurance. The adverse events are still quite important and far more common compared with the average population. Many had subsequent VTE, many died, even if not from pulmonary embolism, and nearly one-half of patients had signs or symptoms of post-thrombotic syndrome at 1-year follow-up.”
Isolated distal DVT, defined as thrombosis in the infrapopliteal veins without coexisting proximal DVT or pulmonary embolism, accounts for 20% to 50% of all DVTs, the researchers wrote in JAMA Cardiology. However, data related to the clinical presentation and outcomes of people with isolated distal DVT have been limited.
Assessing registry data
Bikdeli and colleagues analyzed data from 33,897 patients with isolated distal DVT and 5,938 patients with proximal DVT using data from participating sites of the Registro Informatizado de Pacientes con Enfermedad TromboEmbólica (RIETE) registry, conducted from March 2001 to February 2021. Patients with a history of asymptomatic DVT, upper-extremity DVT, coexisting PE or COVID-19 infection were excluded. Primary outcomes were 90-day and 1-year mortality, 1-year major bleeding and 1-year VTE deterioration, defined as subsequent development of proximal DVT or PE.
Compared with patients with proximal DVT, those with isolated distal DVT had a lower comorbidity burden but were more likely to have had recent surgery or to have received hormonal therapy.
Patients with isolated distal DVT had a lower risk for 90-day mortality compared with those with proximal DVT, for an OR of 0.47 (95% CI, 0.4-0.55). Findings persisted in 1-year adjusted analyses, in which the HR was 0.72 (95% CI, 0.64-0.82).
Those with isolated distal DVT also had a lower 1-year risk for VTE deterioration (HR = 0.83; 95% CI, 0.69-0.99).
Additionally, in 1-year adjusted analyses of patients without an adverse event within the first 3 months, isolated distal DVT was associated with lower risk for VTE deterioration, with an adjusted HR of 0.48 (95% CI, 0.24-0.97). By 1-year follow-up, symptoms or signs of post-thrombotic syndrome were less common in patients with isolated distal DVT compared with patients with proximal DVT (47.5% vs. 59.5%; OR = 0.59; 95% CI, 0.43-0.82).
Clinical implications, unanswered questions
“These results can inform patients and clinicians for decision-making,” Bikdeli, also a clinical investigator at Yale/YNHH Center for Outcomes Research and Evaluation (CORE), and a clinical investigator at the Cardiovascular Research Foundation, told Healio. “For immediate decision-making, distal DVT is less risky. When we talk about natural history of the disease, clinicians and patients can use such information. As a practical example, if one were to hold antithrombotic therapy for a couple of days for a legitimate reason, it will likely incur less risk for patients with distal DVT. But it does not take away from the fact that distal DVT is a serious condition, too.”
Bikdeli said many questions relating to DVT remain unanswered, such as the predictors of adverse outcomes.
“The optimal drug therapy for isolated distal DVT is unknown,” Bikdeli said. “Would it work equally well if we use less intense anticoagulation? How about the duration of treatment? We need randomized trials for that. Our group is discussing these ideas. Last but certainly not least, except for anticoagulation, we currently lack reliable ways to reduce the signs and symptoms of post-thrombotic syndrome. This must be an active area of investigation.”
For more information:
Behnood Bikdeli, MD, MS, can be reached at behnood.bikdeli@yale.edu; Twitter: @bbikdeli.
Collapse
Read more about
Click Here to Manage Email Alerts