title: Resection of the descending thoracic aorta: outcomes after use of hypothermic circulatory arrest.
abstract: BACKGROUND
  Use of hypothermic circulatory arrest (HCA) for operations on the descending thoracic aorta is controversial. While deep hypothermia may provide better end-organ and spinal cord function, prolonged cardiopulmonary bypass and circulatory arrest may increase morbidity. This study assessed outcomes after use of HCA for descending thoracic aortic resection in a large cohort of consecutive patients.
  
  
  METHODS
  Hypothermic circulatory arrest was utilized if arch or extensive descending thoracic aortic resection was required, or if aortic pathology precluded cross-clamping. One hundred thirty-two patients (mean age, 61.3 years) were identified. Diagnosis included fusiform (41.2%) or saccular aneurysm (10.7%) and acute (4.6%) or chronic (38.9%) dissection. Twenty-one patients presented with rupture. Arch resection (distal arch 100, total arch 11) was required in 111 patients (84.1%). The extent of descending thoracic aortic resection (required in 94%) included proximal third in 41 patients, proximal two-thirds in 6, and complete thoracic aorta in 77. The proximal anastomosis was performed with total body HCA while the distal anastomosis was constructed with lower body HCA only (duration upper body HCA 33.7 +/- 8.0 minutes; total duration lower body HCA 71.3 +/- 24.2 minutes).
  
  
  RESULTS
  Thirty-day mortality was 6.0%. Neurologic events included stroke (6.8%) and permanent lower extremity paralysis-paresis (4.5%). Temporary dialysis was needed in 7 (5.3%), though only 2 patients required permanent dialysis (1.9%). Independent predictors of a composite endpoint of death, stroke, permanent paralysis, or dialysis included duration of lower body HCA (p = 0.03) and major postoperative infection (p = 0.003).
  
  
  CONCLUSIONS
  Adjunctive use of deep hypothermic circulatory arrest for descending thoracic aortic resection affords excellent preservation of end-organ and spinal cord function with acceptable rates of mortality and significant morbidity.
authors.affiliation: Section of Cardiac Surgery, Department of Surgery, University of Michigan Hospitals, Ann Arbor, Michigan 48109-0348, USA. hjpatel@med.umich.edu
authors.forename: Himanshu J
authors.initials: HJ
authors.lastname: Patel
authors.forename: Michael S
authors.initials: MS
authors.lastname: Shillingford
authors.forename: Scott
authors.initials: S
authors.lastname: Mihalik
authors.forename: Mary C
authors.initials: MC
authors.lastname: Proctor
authors.forename: G Michael
authors.initials: GM
authors.lastname: Deeb
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology / Q000209:etiology / Q000628:therapy; D000368:Aged; D000714:Anastomosis, Surgical; D000784:Aortic Dissection / Q000601:surgery*; D001013:Aorta, Thoracic / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000601:surgery*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects; D050792:Circulatory Arrest, Deep Hypothermia Induced / Q000009:adverse effects; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010264:Paraplegia / Q000453:epidemiology / Q000209:etiology; D011183:Postoperative Complications / Q000453:epidemiology / Q000401:mortality; D006435:Renal Dialysis; D020760:Spinal Cord Ischemia / Q000453:epidemiology / Q000209:etiology; D020521:Stroke / Q000453:epidemiology / Q000209:etiology; D016019:Survival Analysis; D016896:Treatment Outcome