Whole Blood Viscosity Is a Predictor of Sac Shrinkage after Endovascular Aneurysm Repair

To elucidate the influence of whole blood viscosity (WBV) on sac shrinkage as well as Type 2 endoleaks (T2ELs), reinterventions, and prognosis after endovascular aneurysm repair (EVAR).

This was a single-center retrospective cohort study. Patients who underwent elective index EVAR between 2007 and 2022 and had postoperative follow-up of ≥1 year were reviewed. WBV was estimated using de Simone formula. The primary endpoint was sac shrinkage (≥5 mm decrease) after EVAR, and the secondary endpoints were the incidence of T2EL, reinterventions for sac expansion, and overall survival. Using receiver operating characteristics analysis, a cutoff value of WBV for sac shrinkage was determined.

Of 286 patients, sac shrinkage occurred in 154 (53.8%). Multivariate analysis revealed that WBV level, absence of hostile neck anatomy, and presence of circumferential thrombus were predictors of sac shrinkage. The cutoff value of WBV for sac shrinkage was 44.0 cP. The study cohort was divided into 2 groups: a high-WBV group (WBV ≥ 44.0 cP) and a low-WBV group (WBV < 44.0 cP). The high-WBV group showed a higher sac shrinkage rate (P < .001), lower incidence of T2EL (P = .021), fewer reintervention for sac expansion (P = .038), and higher overall survival (P = .023) than the low-WBV group.

WBV is a positive predictor of sac shrinkage, and elevated WBV is associated with durable success, including a low incidence of T2EL and reintervention for sac expansion after EVAR, without a detrimental effect on prognosis.