Venous thromboembolism (VTE) in multiple myeloma (MM) patients undergoing autologous hematopoietic cell transplantation (HCT).

Abstract

e19503 Background: HCT is commonly used for consolidation for MM patients (pts). These pts have a significant risk of VTE and may potentially be candidates for prophylactic anticoagulation. However, incidence and outcomes of VTE in peri-transplant period remain unclear for MM pts. Methods: Between 2006 and 2016, 160 MM pts underwent autologous HCT at our institution. Peri-transplant period was defined as between initiation of stem cell collection (SCC) and 30 days after discharge from HCT hospitalization. No pts received routine VTE prophylaxis. Clinically significant bleeding was defined as a bleeding event that led to a specific clinical intervention, such as transfusion. We used Cox regression to assess risk factors for peri-transplant VTE. We compared overall survival (OS) using log-rank test. Results: In peri-transplant period, 18 symptomatic VTE occurred in 17 pts (10.6%; 95% CI 7 - 17). Twelve (7.5%) were catheter-related, 4 (2.5%) were non-catheter-related deep venous thrombosis, and 2 (1.3%) were pulmonary emboli. Seven VTE occurred between SCC and HCT. Importantly, among 11 VTE after HCT, only 1 VTE occurred before neutrophil engraftment and only 2 VTE occurred at a platelet count less than 50 x 109/L (median: 138, range: 30 - 464). Clinically significant bleeding occurred in 9 (5.6%) pts during peri-transplant period, without any fatal bleeding. Multivariate analysis was performed including; treatment with immunomodulatory drugs (p = 0.008), HCT comorbidity index ≥ 2 (p = 0.036), age > 60 (p = 0.07), smoking at any time (p = 0.07), BMI > 30 at HCT (p = 0.19), partial remission at HCT (p = 0.20), ISS stage 3 at diagnosis (p = 0.37). At median follow-up of 31 months since HCT, 3-year OS for pts with and without peri-transplant VTE was 58.8% (CI 38% - 91%) and 77.6% (CI 70% - 86%), respectively (p = 0.11). Conclusions: Peri-transplant symptomatic VTE was highly prevalent in our cohort of pts with MM and vast majority of VTE events occurred either between SCC and HCT or after neutrophil engraftment. Our findings indicate that routine VTE prophylaxis in peri-transplant period should be considered for MM pts and timing of VTE prophylaxis can be tailored to optimize balance between safety and efficacy.