Highlights from

ISTH 2020

The International Society of Thrombosis and Haemostasis

Virtual 12-14 July 2020

Residual pulmonary obstruction may predict risk of VTE recurrence

A pooled analysis identified initial pulmonary vascular obstruction index (PVOI) >35% and residual PVOI >5% as cut-off values for prognosis of venous thromboembolism (VTE) recurrence after a first pulmonary embolism (PE).

Experiencing a first episode of PE entails a substantial risk of VTE recurrence and case fatality [1]. "Guidelines do not really take into account all the variability between patients, e.g. for a patient with an unprovoked PE, a life-long anticoagulant therapy is recommended, but only one third of these patients will have benefits from this treatment, leaving the others exposed to hard to justify haemorrhagic risks," Dr Robin Chaux (University Hospital St. Etienne, France) explained, pointing to a need of improved scores to predict recurrence [2]. A promising candidate for risk stratification is the PVOI level.

"In literature, significant associations were found between PVOI and VTE recurrence, but the results are still quite discordant between studies," said Dr Chaux. Furthermore, cut-off values that are used also vary between studies [3-5]. So, apart from evaluating PVOI as potential independent risk factor for VTE recurrence, this analysis by Dr Chaux and colleagues set out to find discriminating threshold values of PVOI to estimate VTE recurrence [1].

To create a substantial sample size, the investigators pooled data of 922 patients from 2 observational studies and 1 randomised controlled trial [3,4,6]. An initial PVOI was determined at the index PE and residual PVOI after 3-6 months of initial anticoagulation therapy. VTE recurrence was defined as objectively confirmed PE or deep vein thrombosis. Study subjects had a history of unprovoked PE in 64.9%.

VTE recurred in 16.2% of patients, and 47.1% received extended anticoagulation over >12 months. Initial PVOI >35% (HR 1.61; 95% transition HR 1.07-2.43) and residual PVOI >5% (HR 1.63; 95% CI 1.06-2.50) were both significantly associated with the risk of VTE recurrence. "So, we have found that initial PVOI and residual PVOI seem to be independent predictors of VTE recurrence after first PE," said Dr Chaux. He concluded, "For the future, we hope that these results, maybe not alone, will help to more accurately detect patients with high risk of VTE recurrence and provide help in clinical decision-making for adapting anticoagulation therapy."

Keywords: Venous thromboembolism, VTE, Pulmonary embolism

Top image: rclassenlayouts

The content and interpretation of these conference highlights are the views and comments of the speakers/authors.