Post Implantation Syndrome and Administration on NSAIDs in Patients Undergoing Endovascular Repair of an Abdominal Aortic Aneurysm Under General Anesthesia

INTRODUCTION Post-implantation syndrome is the clinical and biochemical expression of an inflammatory response following endovascular repair of an aortic aneurysm.1 PIS is mainly a clinical condition associated with the implantation of an endograft and is diagnosed by the presence of fever accompanied by elevated WBC count above normal without any evidence of an infection. The reported incidence of PIS in the literature has been varying widely from 14 to 60%.2-5 The correlation between the type of the endograft placed and the development of PIS may indicate that the inflammatory reaction is due to the material of the endograft itself (polyester or PTFE). Gerasimidis et al. in a relatively underpowered study concluded for the first time in 2005 that fever was more common in a group of patients receiving an endograft made from polyester in contrast to those receiving a PTFE graft. Interleukin 8 (IL-8) was higher in the first group, indicating a stronger host reaction in the specific material. Voute et al. in a later study showed that the implantation of stent grafts based on polyester was independently associated with a stronger inflammatory response. Moulakakis et al., observing a milder inflammatory activation in patients with a PTFE endograft, have confirmed this finding in a later report. Accordingly a previous study found that the use of polyester endograft independently predicted PIS and was correlated with an above 10 times higher risk for an inflammatory response. Based on the results of the above 3 mentioned studies the type of endograft's material seems to play an important role in PIS development and may have a predictive role for a significant number of patients undergoing endovascular repair of abdominal aortic aneurysm ( EVAR ).

The relation of PIS with patient's outcome has not been adequately established. In most studies PIS is considered a benign condition, although it may lead to a more demanding postoperative care characterized by prolonged hospitalization. In a prospective study of 214 patients after EVAR this group found that patients with PIS were more likely to suffer from an adverse event during the 30 days after the procedure. Adverse events occurred in 25.9% of the PIS group compared to 2.9% of the non- PIS group and included any major cardiovascular event, acute renal failure, readmission, and death by any cause. For the same cohort, at the 1-year follow-up, high-sensitivity C-reactive protein and interleukin 6 were attenuated toward the values of the non-PIS group. During the one-year follow-up period, MACE and adverse events occurred, respectively, in 17.2% and in 18.8% of patients in the PIS group and in 4.3% and 5.1% of the non-PIS group. The occurrence of PIS was the only independent predictor of a MACE or an adverse event during the follow-up period.

Current available literature data certainly raise the question of altering current therapeutic approach and treat patients with PIS by focusing on the reduction of the inflammatory response by administration of steroid or non-steroidal drugs. Motte et al published recently a prospective trial of 150 EVAR patients who were randomized to receive a single preoperative dose of methylprednisolone or placebo. The inflammatory response, as assessed by the inflammatory biomarkers levels, was reduced in the methylprednisolone group, although no differences were noted in patient outcomes between the two groups during a 3-month follow-up period. Data on postoperative use of anti-inflammatory drugs are absent.

Because PIS was the only independent predictor of an adverse event during the first year after EVAR, it seems that even a strong inflammatory stimulus at the immediate postoperative period could probably affect the cardiovascular health of these patients at the long term. Any therapeutic measurements that might thus focus on PIS acute treatment or even prevention seem reasonable.

The aim of the present randomized placebo-controlled study is to evaluate whether the perioperative administration of Naproxen (NPR) an anti-inflammatory drug with a beneficial cardiovascular safety profile17 in patients with an abdominal aortic aneurysm undergoing endovascular repair could have any effect on the inflammatory response and patients outcome during the first year of follow-up after surgery.