title: Abdominal aortic calcification and surgical outcomes in patients with no known cardiovascular risk factors.
abstract: BACKGROUND
  In the setting of cardiovascular (CV) risk evaluation before major elective surgery, current risk assessment tools are relatively poor for discriminating among patients. For example, patients with clinical CV risk factors can be clearly identified; but among those without appreciated clinical CV risk, there may be a subset with stigmata of CV disease noted during the preoperative radiographic evaluation. Our study evaluated the relationship between abdominal aortic (AA) calcification measured on preoperative computed tomography (CT) imaging and surgical complications in patients undergoing general elective and vascular surgery. We hypothesized that patients with no known CV risk factors but significant aortic calcification on preoperative imaging will have inferior surgical outcomes.
  
  
  METHODS
  The study group included 1180 patients from the Michigan Surgical Quality Collaborative (MSQC) database who underwent major general or vascular elective surgery between 2006 and 2009 and who had a CT scan of the abdomen specifically for preoperative planning. AA calcification was measured using novel analytic morphomic techniques and reported as a percentage of the total wall area containing calcification. Patients were divided into cohorts by clinical CV risk and extent of AA calcification. Univariate analysis was used to compare postoperative morbidity between patient cohorts. Multivariate logistic regression analysis was used to compare continuous AA calcification with overall morbidity in patients with no clinical CV risk factors.
  
  
  RESULTS
  AA calcification was strongly skewed to the right (53.5% had no AA calcification) and was significantly correlated with age (ρ = 0.43, P < 0.001). Unadjusted univariate analysis of morbidity showed no significant differences in complication rates between patients in the clinical CV risk and significant AA calcification (no known CV risk factor) categories. The clinical CV risk (P < 0.001) and significant AA calcification without CV risk factors (P = 0.009) populations both had significantly more infectious and overall complications than patients with no AA calcification and no clinical CV risk. Multivariate logistic regression confirmed that AA calcification was a significant predictor of morbidity in patients with no clinical CV risk factors (odds ratio = 1.35, P = 0.017).
  
  
  CONCLUSIONS
  This study suggests that AA calcification may be related to progression of CV disease and surgical outcomes. A better understanding of the complex interaction of patient physiology with overall ability to recover from major surgery, using novel approaches such as analytic morphomics, has great potential to improve risk stratification and patient selection.
authors.affiliation: Academic Surgery Interest Group, Department of Surgery, University of Michigan, Ann Arbor, MI 48109–5331, USA.
authors.forename: Calista M
authors.initials: CM
authors.lastname: Harbaugh
authors.forename: Michael N
authors.initials: MN
authors.lastname: Terjimanian
authors.forename: Jay S
authors.initials: JS
authors.lastname: Lee
authors.forename: Abbas Z
authors.initials: AZ
authors.lastname: Alawieh
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Kowalsky
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Tishberg
authors.forename: Robert W
authors.initials: RW
authors.lastname: Krell
authors.forename: Sven A
authors.initials: SA
authors.lastname: Holcombe
authors.forename: Stewart C
authors.initials: SC
authors.lastname: Wang
authors.forename: Darrell A
authors.initials: DA
authors.lastname: Campbell
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Englesbe
mesh_terms: D001012:Aorta, Abdominal / Q000473:pathology*; D001018:Aortic Diseases / Q000473:pathology*; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000209:etiology; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012307:Risk Factors; D061205:Vascular Calcification / Q000473:pathology*