title: Suprarenal aortic cross-clamp position: a reappraisal of its effects on outcomes for open abdominal aortic aneurysm repair.
abstract: OBJECTIVE
  With the increasing use of endovascular aneurysm repair, a greater proportion of open aneurysm repairs in the future are expected to be more complex and require suprarenal cross-clamping. We sought to evaluate the effects of suprarenal (SR) vs infrarenal (IR) aortic cross-clamp position in abdominal aortic aneurysm (AAA) repair in an updated single center series.
  
  
  METHODS
  All elective open AAA repairs performed at our institution between 1990 and 2006 were entered into a prospective database and reviewed retrospectively. Our main stratification variable was SR vs IR. The SR group was further subdivided into those requiring an adjunctive renal revascularization procedure (SR+RRP; n = 54) and those who did not (SR-RRP; n = 117). Univariate and multivariate models were used to analyze the effect of baseline variables and operative variables on our primary endpoint 30-day mortality as well as secondary endpoints such as major adverse events, postoperative decline in renal function (defined as doubling of baseline creatinine to level >2 mg/dL, or new-onset dialysis) and long-term survival. A propensity score model was developed to control for confounding variables associated with the use of an SR cross-clamp.
  
  
  RESULTS
  A total of 1020 patients underwent elective AAA repair, of which 849 (83.2%) were IR and 171 (16.8%) were SR. Diabetes (14.6% vs 9.1%, P = .027), hypertension (70.2% vs 61.4%, P = .03), and chronic renal failure (14.0% vs 4.7%, P = .001) were more prevalent in the SR group, and mean aneurysm size was larger (6.0 cm vs 5.6 cm, P = .001). Estimated blood loss was higher (1919 mL vs 1257 mL, P = .001) in the SR group, as was mean length of stay (12.6 days vs 10.7 days, P = .047). Perioperative (30-day) mortality rate was 1.8% for the SR group and 1.2% for the IR group (P = .44). Postoperative decline in renal function was 17.0% in SR vs 9.5% in IR (P = .003), however, new-onset dialysis was rare (0.6% SR, 0.8% IR, P = NS). The combination of SR+RRP was associated with an increased risk for postoperative decline in renal function (14.8% SR+RRP, 4.3% SR-RRP, P = .016). Preoperative renal failure was strongly associated with postoperative renal decline (odds ratio [OR] 8.15, 2.92-22.8, P < .0001). Propensity score analysis demonstrated that the use of an SR cross-clamp was associated with an increased risk for postoperative renal decline (OR 2.66, 1.28-5.50, P = .009). Major adverse events were more prevalent in the SR group compared to the IR group (17.0% vs 9.5%, P = .003). Five-year survival was 69.1% + 1.9% for the IR group and 67.7% + 4.3% for the SR group (P = 0.38) by life table analysis.
  
  
  CONCLUSIONS
  Suprarenal cross-clamping is associated with low mortality and significant but acceptable morbidity, including postoperative decline in renal function. The results from this series may serve as relevant background data when evaluating emerging branched and fenestrated endograft technologies.
authors.affiliation: Department of Vascular Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass, USA.
authors.forename: Tec
authors.initials: T
authors.lastname: Chong
authors.forename: Louis
authors.initials: L
authors.lastname: Nguyen
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Owens
authors.forename: Michael S
authors.initials: MS
authors.lastname: Conte
authors.forename: Michael
authors.initials: M
authors.lastname: Belkin
mesh_terms: D000368:Aged; D001011:Aorta / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation / Q000401:mortality; D003250:Constriction; D019992:Databases as Topic; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D016016:Proportional Hazards Models; D011474:Prosthesis Design; D006435:Renal Dialysis; D051437:Renal Insufficiency / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors; D016896:Treatment Outcome