title: Relation between activated clotting time during angioplasty and abrupt closure.
abstract: BACKGROUND
  The purpose of this study was to determine whether the degree of heparin anticoagulation during coronary angioplasty, as measured by the activated clotting time, is related to the risk of abrupt vessel closure.
  
  
  RESULTS
  Sixty-two cases of in- and out-of-laboratory abrupt closure in patients in whom intraprocedure activated clotting times were measured were identified from a population of 1290 consecutive patients who underwent non-emergency coronary angioplasty. This group was compared with a matched control population of 124 patients who did not experience abrupt closure. Relative to the control population, patients who experienced abrupt closure had significantly lower initial (median, 350 seconds [25th to 75th percentile, 309 to 401 seconds] versus 380 seconds [335 to 423 seconds], P = .004) and minimum (345 seconds [287 to 387 seconds] versus 370 seconds [321 to 417 seconds], P = .014) activated clotting times. Higher activated clotting times were not associated with an increased likelihood of major bleeding complications. Within this population, a strong inverse linear relation existed between the activated clotting time and the probability of abrupt closure.
  
  
  CONCLUSIONS
  This study demonstrates a significant inverse relation between the degree of anticoagulation during angioplasty and the risk of abrupt closure. A minimum target activated clotting time could not be identified; rather, the higher the intensity of anticoagulation, the lower the risk of abrupt closure.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: C R
authors.initials: CR
authors.lastname: Narins
authors.forename: W B
authors.initials: WB
authors.lastname: Hillegass
authors.forename: C L
authors.initials: CL
authors.lastname: Nelson
authors.forename: J E
authors.initials: JE
authors.lastname: Tcheng
authors.forename: R A
authors.initials: RA
authors.lastname: Harrington
authors.forename: H R
authors.initials: HR
authors.lastname: Phillips
authors.forename: R S
authors.initials: RS
authors.lastname: Stack
authors.forename: R M
authors.initials: RM
authors.lastname: Califf
mesh_terms: D000368:Aged; D000800:Angioplasty, Balloon / Q000009:adverse effects*; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects; D016022:Case-Control Studies; D003251:Constriction, Pathologic / Q000209:etiology; D003331:Coronary Vessels / Q000473:pathology / Q000601:surgery*; D005260:Female; D006470:Hemorrhage / Q000209:etiology; D006493:Heparin / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014914:Whole Blood Coagulation Time
chemical_list: D006493:Heparin