Among patients with sickle cell disease (SCD), surgical splenectomy was associated with increased risk of venous thromboembolism (VTE) events, particularly pulmonary embolism (PE) rather than isolated deep vein thrombosis (DVT), according to study results presented at the Thrombosis & Hemostasis Summit of North America (THSNA) 2020 Virtual Conference.
As little is known about the long-term risks of splenectomy in patients with SCD, researchers aimed to investigate the relationship between splenectomy and VTE and other vascular outcomes in this patient population.
The cross-sectional study leveraged a well-phenotyped group of adult patients with SCD who had prospectively enrolled in the Globin Research Network for Data and Discovery (GRNDaD) registry, a combined effort from 6 US-based SCD clinical sites. All patients had complete information for the primary outcomes, which were VTE, PE, isolated DVT, and cerebral vascular events. The investigators evaluated the association between surgical splenectomy and VTE, with adjustments for age, sex, and genotype.
A total of 684 patients with SCD were included in the study. When categorized by genotype, 479 (70.0%) patients had the SS/Sβ0 genotype, 149 (21.9%) had the hemoglobin SC genotype, and 56 (8.2%) had the Sβ+-thalassemia genotype. Overall, 77 patients (11.3%) had undergone surgical splenectomy.
Compared with the nonsplenectomized group, patients with splenectomy were younger (mean age, 33 vs 36 years; P =.035) and had significantly higher baseline hemoglobin levels (9.9 vs 9.3 g/gL; P =.03) and platelet counts (384 vs 342 K/cu mm; P =.02).
Patients with splenectomy had a significantly higher prevalence of VTE (P =.03) compared with those without splenectomy; however, both groups had similar prevalence of stroke (P =.12) and moyamoya (P =.19). Furthermore, patients with splenectomy were 2.1 times (95% CI, 1.3-3.6) more likely to have had a VTE, more often PE (odds ratio [OR], 2.4; 95% CI, 1.3-4.2) rather than isolated DVT (OR, 1.4; 95% CI, 0.6-3.0), than patients without splenectomy.
In the subgroup analysis, the risk of VTE varied among SCD genotypes. Patients with the SS/Sβ0 genotype and splenectomy did not have increased risk of VTE compared with their counterparts without splenectomy. Patients with SC or Sβ+-thalassemia genotypes and splenectomy had a 5.0 times (95% CI, 1.7-14.2) greater risk of VTE compared with their counterparts without splenectomy, and more specifically, patients with Sβ+-thalassemia and splenectomy had an 11.7 times (95% CI, 1.83-74.5) greater risk of PE than their counterparts without splenectomy.
“In this large cohort of SCD patients, surgical splenectomy was associated with increased risk of VTE events, which was primarily attributable to an increased risk of PE rather than isolated DVT,” concluded the authors. “Future studies are needed to further characterize the association of splenectomy and functional asplenia on vascular outcomes in SCD.”
Chen J, Plazas Montana M, Williams E, et al. Surgical splenectomy and risk of venous thromboembolism in sickle cell disease. Abstract presented at: THSNA 2020 Thrombosis & Hemostasis Summit of North America; October 27-30, 2020. Abstract 39.