# Venous thromboembolism in lung transplant recipients: timing and clinical impact, a 10-year cohort analysis

## TL;DR

This study finds that nearly one-third of lung transplant patients develop blood clots, mostly within the first six months, with a link to reduced long-term lung function.

## Contribution

The study provides a 10-year analysis of VTE timing and its impact on graft and CLAD-free survival in lung transplant recipients.

## Key findings

- 33% of lung transplant recipients developed VTE, with 71% occurring within the first 6 months.
- 70% of VTE events were pulmonary embolism, but severe or fatal cases were rare.
- Late VTE was associated with shorter CLAD-free survival but not graft survival.

## Abstract

The burden of venous thromboembolism (VTE) in lung transplant (LTx) recipients is not fully elucidated despite its frequent occurrence. We report the incidence of VTE and characteristics of VTE in a large LTx cohort, assess severity using risk stratification algorithms, and explore associations with graft survival and chronic lung allograft dysfunction (CLAD).

A retrospective cohort analysis was performed on LTx recipients transplanted between July 2012 and August 2022 in our center. Primary outcome was incidence of VTE. Three groups were compared as follows: patients with early VTE (i.e., within the first 6 months after LTx), late VTE (i.e., beyond the first 6 months after LTx), and no VTE.

About 94/286 patients (33%) were diagnosed with VTE (median follow-up of 4.3 years): 67/94 (71%) early VTE and 27/94 (29%) late VTE. 66/94 (70%) of VTE events were pulmonary embolism (PE). In the early VTE group, none of the PE cases were classified as intermediate-high risk PE and 1 patient had high-risk (fatal) PE. Graft survival was not different between groups; median CLAD-free survival was shorter in patients with late VTE (6.2 years) compared to patients without VTE during follow-up (9.8 years) (p = 0.044).

Thirty-three percent of LTx recipients developed VTE, 71% within the first 6 months after LTx. Seventy percent of cases were acute PE, but fatal or severe nonfatal PE were rare. No effect of VTE on graft survival was seen; CLAD-free survival was shorter in patients with late VTE compared to patients without VTE.