A new study highlights key differences in clinical features and comorbidities, as well as short-term and also long-term outcomes for patients with distal deep vein thrombosis (DVT) versus proximal DVT. The findings were recently published in JAMA Cardiology.
The differences between the clinical presentation, short-term and long-term outcomes for patients with isolated distal DVT (smaller thrombi in veins below the knee) versus proximal DVT have been unclear, Behnood Bikdeli (Brigham and Women’s Hospital, Boston, USA) and colleagues write.
In order to investigate this gap in the literature, the researchers conducted a multicentre, international cohort study in participating sites of the Registro Informatizado Enfermedad Tromboembólica (RIETE) registry from 1 March 2001 though 28 February 2021.
The team found that patients with isolated distal DVT had lower comorbidity burden and a lower risk of 90-day mortality. They were also at lower risk of developing a pulmonary embolism or a new venous thromboembolism (VTE) in one year.
The authors note that some of the differences in the outcomes are attributable to the risk profile of these patients. Patients with distal DVT were younger, more likely to have had DVT in the setting of transient provoking factors such as surgery or hormonal use but less likely to have serious comorbidities such as cancer or anaemia.
“Our findings may have implications for risk stratification and for practice,” said Bikdeli. “While we find less ominous outcomes for isolated, distal DVTs, they are not entirely benign. Even among patients who received initial anti-coagulation treatment, almost half had signs or symptoms of post-thrombotic syndrome, a chronic manifestation of these clots. Randomised clinical trials are needed to assess the best long-term management for patients who have had isolated, distal DVT.”