Time-to-Event Analysis of the Impact of Endovascular Aortic Aneurysm Repair on Chronic Renal Decline.

BACKGROUND: Although randomized studies have revealed the long-term outcomes of the endovascular repair (ER) of abdominal aortic aneurysm (AAA) compared to open repair (OR), there is controversy surrounding chronic renal decline (CRD) after ER. This study reviewed our propensity-matched cohorts of ER and OR to compare CRD rates using a time-to-event analysis. The ER groups undergoing suprarenal (SR) or infrarenal (IR) proximal fixation were also compared with the OR group. METHODS: This retrospective review of infrarenal AAA repair was conducted from June 2007-December 2017. Patients with ≥1 year of follow-up were included. Cases of supra/pararenal AAAs, infectious AAAs, rupture, or severe chronic kidney disease (CKD) (estimated glomerular filtration rate (eGFR) <15 mL/min/1.73 m2 or dependence on renal replacement therapy) were excluded. CRD was defined as eGFR decline of >20% or de novo hemodialysis during follow-up. Patients treated with ER (ER group) and OR (OR group) were propensity-score matched for age, sex, comorbidities, ejection fraction, respiratory function, and baseline eGFR. Kaplan-Meier analysis compared the freedom from CRD rates of the matched cohorts (mER and mOR groups). Patients treated with SR and IR fixation devices (SR and IR groups) were also separately matched to the OR group, followed by analysis. RESULTS: In total, 1087 patients underwent elective AAA repair. Among them, 944 (512 ER and 432 OR) were enrolled. The ER group was older than the OR group (median age 79 vs 71; P<0.001). The ER group had significantly lower baseline eGFR and more comorbidities than the OR group. Among 187 propensity-score matched pairs (187 mER and 187 mOS patients), background characteristics, including age and baseline eGFR, were comparable, but median renal function follow-up was significantly longer in the mER group than in the mOR group (48 vs 26 months; P<0.001). CRD was observed in 57 patients in the mER group and 30 patients in the mOR group. Kaplan-Meier analysis of the freedom from CRD showed no significant difference between the matched groups (P=0.268); however, in the later follow-up of >4 years, CRD was more common in the mER group. The matched analyses between the OR group and specific fixation groups, comprising 102 OR-SR and 73 OR-IR pairs, demonstrated no significant differences in CRD. CONCLUSIONS: Compared to OR, there was no significant impact of ER on CRD at up to 4 years, supporting the safety of ER in terms of the mid-term renal outcome of our present clinical practice.

Clinical Comparison between Early and Late Spontaneous Sac Shrinkage after Endovascular Aortic Aneurysm Repair.

BACKGROUND: Early spontaneous shrinkage (ESS) of abdominal aortic aneurysm (AAA) within 1 year after endovascular aortic aneurysm repair (EVAR) could be a predictor of durable success. However, late spontaneous shrinkage (LSS) during longer follow-up has not been well addressed. We compared late complications of ESS and LSS. METHODS: Our series of elective EVAR for infrarenal AAA from June 2007 to December 2017 was reviewed. Patients with ≥1 year of follow-up with computed tomography (CT) studies were included. Patients with any reintervention within 1 year were excluded. Spontaneous shrinkage (SpS) was defined as a diameter reduction ≥10 mm without any reintervention. ESS was defined as SpS within 1 year, and LSS was defined as SpS occurring after 1 year of follow-up. Aneurysms that became larger than the original size after SpS were defined as re-expansion. Late complications (re-expansion, reintervention, and aneurysm-related death) and related factors were compared between ESS and LSS. RESULTS: A total of 495 patients were enrolled. Median follow-up was 43 months [24-67, interquartile range (IQR)]. Among patients, 126 ESS and 55 LSS occurred. The cumulative rates of SpS were 25.7±2.0%, 37.4±2.4%, and 47.3±3.7% at 1, 3, and 7 years, respectively. There was 1 re-expansion and 6 reinterventions during further follow-up after SpS. The rates of freedom from late complications at 5 years were not significantly different between ESS (89.2±4.0%) and LSS (95.8±4.1%) (P = 0.465). Regression analysis revealed that the Zenith device was significantly related to ESS compared to the Excluder (P = 0.006) and Endurant (P = 0.040) . More than 6 preoperative patent lumbar arteries negatively correlated with ESS (P = 0.023). However, these factors had no significant impact on LSS. CONCLUSIONS: The rates of late complications after SpS were comparable between ESS and LSS. Patients with delayed sac shrinkage with a reduction in diameter ≥10 mm should expect the same durable success as patients with quick shrinkage.