Risk Factors and Perioperative Outcomes of Postimplantation Syndrome After Thoracic Endovascular Aortic Repair

Objective: Postimplantation syndrome (PIS) is a systemic inflammatory response that occurs following abdominal endovascular aortic repair (EVAR) and thoracic EVAR (TEVAR). The main outcome was to individuate the incidence and risk factors of PIS after TEVAR. Its impact on the length of stay and clinical outcomes were secondary objectives. Materials and Methods: Three hundred sixty-nine consecutive TEVAR procedures performed between February 2010 and November 2022 were included in this retrospective cohort, observational, single-center study. Patients with proximal landing in zones 0 to 5 were enrolled. Data on comorbidities, previous aortic surgery and morphology, thoracic aorta coverage, stent-graft composition, intraoperative variables, and postoperative outcomes were collected. White blood cell (WBC) and C-reactive protein (CRP) serum levels were recorded preoperatively and 48 hours after TEVAR. PIS was defined as the concomitant presence of fever (tympanic temperature ≥38.0°C), CRP serum level >0.7 mg/dl and evidence of pleural effusion on postoperative chest radiograph. Results: PIS incidence in our cohort was 26.8%. PIS patients presented with a higher rate of hyperlipidemia (56.6% vs 44.8%, p = 0.045) than non-PIS patients. Stent-graft composition did not play a relevant role in eliciting PIS. PIS was a statistically significant factor in prolonging patients’ stay (median 16.0 days vs 8.0 days, p < 0.001, PIS and non-PIS patients). Thoracic aortic coverage >150 mm (Odds Ratio (OR) 4.7, p = 0.004), coronary artery disease (OR 2.1, p = 0.028), and preoperative WBC count (OR 1.1, p = 0.047) were identified as risk factors for PIS, whereas previous aortic surgery (OR 0.5, p = 0.05) was highlighted as a protective factor. Thoracic aortic coverage was a significant risk factor for increased WBC and CRP levels (p < 0.001). Conclusion: PIS incidence was 26.8% in our cohort. Thoracic aortic coverage, coronary artery disease, and preoperative WBC count were identified as risk factors for PIS after TEVAR, whereas previous aortic surgery was found to be a protective factor. PIS also appeared to have a significant impact on length of stay. Clinical Impact This study identified a significant occurrence of post-implantation syndrome (PIS) following TEVAR, affecting over 25% of patients and adversely affecting the duration of hospital stay. Stent graft material did not seem to influence the incidence of PIS. Thoracic aortic coverage, coronary artery disease, and preoperative white blood cell (WBC) count have been identified as risk factors, whereas previous aortic surgery has been found to serve as a protective factor, representing a novel finding in the literature. Further research is warranted to ascertain strategies for mitigating the incidence of PIS, considering the risk factors identified in both current and prior studies. In addition, it is necessary to evaluate the potential implementation of preoperative prophylactic therapy for PIS in patients undergoing TEVAR.