Red blood cell distribution width (RDW) is an independent predictor of post-implantation syndrome in patients undergoing endovascular aortic repair for abdominal aortic aneurysm

Background: This observational, retrospective study aims establishing the role of red blood cell distribution width (RDW) for identifying abdominal aortic aneurism (AAA) patients at risk of developing post-implantation syndrome (PiS) after endovascular aneurysm repair (EVAR). Methods: The study population consisted of all patients undergoing EVAR for AAA at the University Hospital of Verona (Italy), between June 1, 2016 and May 31, 2018. Blood samples for measuring hemoglobin, mean corpuscular volume (MCV) and RDW were collected at hospital admission and the day after EVAR. The primary endpoint was PiS development. Delta variations were calculated as the ratio between values measured after and before EVAR. Results: The final study population consisted of 124 patients (10 women and 114 men; median age, 75 years), 55 of whom developed PiS. In patients with or without PiS hemoglobin significantly decreased after EVAR, whilst RDW significantly increased in patients with PiS and decreased in those without. Age, sex, hypertension, diabetes and renal failure were similar in patients who developed PiS or not, whilst a positive history of coronary artery disease was more frequent in PiS patients. Although hemoglobin and MCV changes after EVAR did not differ in patients with or without PiS, delta RDW was higher in those with PiS. The rate of patients with delta RDW >1 was significantly higher in patients with PiS that in those without (61.8% vs. 34.8%; P=0.002). In multivariate analysis, delta RDW remained independently associated with PiS (β coefficient, 2.023; P=0.001). A delta RDW >1 after EVAR was associated with ~3-fold enhanced risk of PiS (odds ratio, 3.04; P=0.003) and exhibited a good prognostic performance (area under the curve, 0.69; P<0.001). Conclusions: Calculation of delta RDW after EVAR seems an efficient prognostic tool for stratifying the risk of developing PiS, especially in the early postoperative period.