title: Chronic kidney disease classification stratifies mortality risk after elective stent graft repair of the thoracic aorta.
abstract: OBJECTIVE
  Risk factors for perioperative and late mortality after thoracic endovascular aortic repair (TEVAR) remain ill-defined. In this study, we examined the prognostic significance of chronic kidney disease (CKD), a well-known predictor of death after thoracic aorta open repair, employing a stratification based on CKD stages derived from glomerular filtration rate (GFR) values.
  
  
  METHODS
  A prospective database was evaluated for 179 consecutive patients electively submitted to TEVAR between 1999 and 2007. Preoperative GFR was estimated by using the Cockcroft-Gault equation. Patient groups were stratified into four quartiles by baseline serum creatinine (SC) and GFR values, with quartile I being the lowest, and quartile IV the highest, and into the five CKD stages in reverse order (I GFR >or= 90 ml/min/1.73 m(2); II 60-89; III 30-59; IV 15-29; V < 15). Prognostic significance of preoperative GFR values and CKD stages were investigated by means of univariate and multivariate analyses, and the Kaplan-Meier log-rank method.
  
  
  RESULTS
  A primary technical success was achieved in 166 of 179 patients (92.7%), and an initial clinical success in 158 (88.3%). Thirty-day mortality was 5% (nine cases). Paraplegia or paraparesis were observed in 11 (6.1%) patients, and completely resolved in six cases after cerebrospinal fluid drainage. Preoperative GFR quartiles and CKD stages were significant predictors of 30-day mortality (P = .004 and P < .0001 respectively), whereas SC quartiles did not affect the outcome (P = .12). In particular, GFR quartile I (<60 ml/min/1.73 m(2)) was associated with a ten-fold greater risk of perioperative death compared with the other three quartiles (Odds Ratio 11.4, 95% Confidence Interval 2.3-57.0, P = .003). Midterm survival was 88.8% (159 of 179) at a mean follow-up of 35.6 +/- 23.7 months. Actuarial survival at 60 months was 57.8%, 81.1%, 92.3%, and 100% for GFR quartiles I to IV respectively (P < .0001), and 0.0%, 66.7%, 59.2%, 88.6%, and 100% (P < .0001) for CKD stage V to I respectively. At univariate analyses, age (P = .019), preoperative SC quartiles (P = .001), GFR quartiles (P = .0002), and CKD stages (P < .0001) were all predictive of mid-term mortality. At multivariate Cox proportional hazards regression analysis, only CKD stages remained independently associated with the outcome (P = .008).
  
  
  CONCLUSIONS
  GFR is an accurate prognostic predictor in patients submitted to TEVAR. Also, perioperative and midterm mortality directly correlate with the severity of CKD stages, allowing a risk stratification model to be employed both for risk-adjusted preoperative evaluation, and to establish accurate matching criteria for comparative studies.
authors.affiliation: Department of Vascular Surgery, San Raffaele Scientific Institute, Università Vita-Salute, Milan, Italy. max_marrocco@yahoo.com
authors.forename: Massimiliano M
authors.initials: MM
authors.lastname: Marrocco-Trischitta
authors.forename: Germano
authors.initials: G
authors.lastname: Melissano
authors.forename: Andrea
authors.initials: A
authors.lastname: Kahlberg
authors.forename: Giliola
authors.initials: G
authors.lastname: Calori
authors.forename: Francesco
authors.initials: F
authors.lastname: Setacci
authors.forename: Roberto
authors.initials: R
authors.lastname: Chiesa
mesh_terms: D000368:Aged; D001018:Aortic Diseases / Q000150:complications / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000401:mortality; D002908:Chronic Disease; D003404:Creatinine / Q000097:blood; D019992:Databases as Topic; D017558:Elective Surgical Procedures; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D053208:Kaplan-Meier Estimate; D007674:Kidney Diseases / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D015607:Stents; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003404:Creatinine