Survival in Patients With Evidence of Pulmonary Thromboembolism on Ventilation-Perfusion SPECT 12 Weeks After Double Lung Transplantation: A Retrospective Cohort Study

Abstract

Background

Patients who have undergone double lung transplantation (DLTx) are at increased risk of pulmonary thromboembolism (PTE). Although the presence of clinically overt PTE can adversely affect short-term mortality, the prognostic impact of asymptomatic (silent) PTE detected by routine imaging after DLTx is unclear. This study aimed to determine whether PTE identified by routine ventilation-perfusion single-photon emission computed tomography (V̇-Q̇ SPECT) 12 weeks post-DLTx is associated with subsequent all-cause and graft-related mortality.

Methods

Single-center retrospective cohort study evaluating 130 DLTx recipients who underwent routine V̇-Q̇ SPECT imaging 12 weeks posttransplant between 2012 and 2017. V̇-Q̇ SPECT scans were assessed for perfusion and ventilation defects indicative of PTE. The association between PTE and mortality outcomes was analyzed using multivariable Cox regression, Kaplan-Meier survival curves, and cumulative incidence functions.

Results

PTE was identified in 24.6% (n = 32) of the patients 12 weeks post-DLTx. After 3 months of follow-up, there was no detectable difference in lung function between patients with and without PTE. Moreover, the presence of PTE was not associated with increased hazard ratios for all-cause mortality (HR = 0.72; 95% CI: 0.37–1.41; p = 0.34) or graft-specific mortality (HR = 0.95; 95% CI: 0.42–2.16; p = 0.91).

Conclusions

PTE is a frequent finding on routine V̇-Q̇ SPECT 12 weeks post-DLTx that does not inform risk of all-cause or graft-related mortality. These findings suggest that an incidentally detected PTE in asymptomatic patients may not necessitate changes in clinical management for asymptomatic DLTx patients.