Risk Factors For Late Mortality Following Endovascular Thoracic Aneurysm Repair

BACKGROUND:
To identify risk factors for late mortality after thoracic endovascular aortic repair (TEVAR).
METHODS:
A retrospective analysis of a prospectively maintained database of consecutive TEVAR was conducted. Thirty day and late survival were determined by chart review, telephone contact, or query of the Social Security Death Index. Late mortality was assessed with respect to patient characteristics at the time of initial treatment (age, gender, pulmonary, cardiac and renal disease, hypertension, hyperlipidemia, diabetes, medication) pre-operative laboratory values (albumin, hemoglobin, white blood cell (WBC) count, platelet count, creatinine), pathology (aneurysm type, diameter), clinical presentation (symptomatic, rupture), and treatment adjuncts (debranching). Variables found to be significant by univariate analysis were entered into a multivariate Cox regression model to ascertain independent predictors of mortality.
RESULTS:
From 1998 and 2009, 252 patients (median 70 years, 149 males) underwent TEVAR for degenerative thoracic aortic aneurysm (TAA, n = 143), Type B dissection (n = 62), mycotic aneurysm (n = 13), traumatic disruption (n = 12), penetrating ulcer/intramural hematoma (n = 10), anastomotic pseudoaneurysm (n = 4), or other pathology (n = 8). Thirty day mortality was 9.5% with stroke or spinal cord injury in 5.6%. Follow-up was 22 ± 22 months (mean ± SD) with a Kaplan-Meier mean survival of 53 months. Predominant causes of late death were cardiac disease, malignancy, and COPD. Predictors of late mortality by univariate analysis included age (p < 0.01), cardiac arrhythmia (p = 0.03), COPD (p=0.05), hyperlipidemia (p = 0.03), statin use (p = 0.02), aneurysm diameter (p < 0.01), rupture, and elevated creatinine (p = 0.01). Multivariate analysis revealed that rupture (hazard ratio 3.1, 95% CI 1.02 to 9.44, p = 0.03), debranching (hazard ratio 2.20, 95% CI 1.09 to 4.24, p = 0.03), preoperative WBC count (hazard ratio 1.23, 95% CI 1.09 to 1.39, p = 0.001), and aneurysm diameter (hazard ratio 1.02, 95% CI 1.01 to 1.03, p = 0.04) were independent predictors of late mortality. Subgroup analysis of patients undergoing elective TEVAR for asymptomatic, non-ruptured TAA demonstrated that debranching (hazard ratio 2.47, 95% CI 1.13 to 5.39, p = 0.02), WBC count (hazard ratio 1.19, 95% CI 1.01 to 1.40, p < 0.04), and aneurysm diameter (hazard ratio 1.03, 95% CI 1.01 to 1.05, p < 0.01) remain independently predictive of late mortality (Fig. 1).
CONCLUSIONS:
Despite adequate initial repair, long-term survival after TEVAR remains compromised. Concurrent debranching, preoperative WBC count, and aneurysm diameter independently predict late mortality irrespective of clinical presentation and may assist in risk stratification.