# Incidence of Venous Thromboembolism After Surgery for Acute Stanford Type A Aortic Dissection

## TL;DR

This study finds that 16% of patients develop DVT after surgery for aortic dissection, with a higher risk of PTE in those with DVT.

## Contribution

First investigation into venous thromboembolism incidence after acute Stanford type A aortic dissection surgery.

## Key findings

- 16.1% of patients developed postoperative deep vein thrombosis.
- Pulmonary thromboembolism occurred in 13.3% of DVT patients but none in non-DVT patients.
- D-dimer levels were not reliable indicators of venous thromboembolism in these patients.

## Abstract

Background

The incidence of postoperative deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE) following acute Stanford type A aortic dissection (AADA) has not been investigated. Therefore, this study aimed to determine the incidence and risk factors of DVT and PTE following AADA.

Methods

This study included all patients who underwent emergency surgery for AADA at Ayase Heart Hospital, Tokyo, Japan, between April 1, 2023, and October 31, 2025. We excluded patients with preoperative venous thromboembolism (VTE), those who could not undergo postoperative lower extremity venous ultrasonography, and those who were undergoing anticoagulant therapy at the time of the postoperative ultrasound examination. DVT was assessed using lower extremity venous ultrasonography immediately before surgery and on the second postoperative day. Patients with DVT on postoperative lower extremity venous ultrasonography were grouped into the DVT group, while those who did not have DVT were grouped into the non-DVT group. The primary endpoint was the incidence of DVT, and the secondary endpoint was the incidence of PTE.

Results

Ninety-three of the 115 cases were included in the analysis. The DVT and non-DVT groups comprised 15 (16.1%) and 78 patients (83.9%), respectively. The incidence of PTE was significantly higher in the DVT group than in the non-DVT group (two cases: 13.3% vs. 0 cases: 0%; p = 0.01; χ2 = 10.63; effect size: 0.34). No significant differences were found between the two groups in terms of other intraoperative and postoperative outcomes. The low incidence of DVT events resulted in insufficient statistical power, precluding the identification of independent risk factors in the multivariate analysis.

Conclusions

AADA often presents with elevated preoperative D-dimer levels, which frequently persist into the postoperative period. Consequently, the D-dimer level may not be a reliable indicator of VTE in these patients. The incidence of PTE in patients with AADA was 2.2% (n=2/93), the critical importance of both prevention and early detection of DVT. Lower extremity venous ultrasonography may be effective for DVT screening in patients after AADA surgery, complementary to conventional DVT prevention protocols.