title: Platelet aggregometry can accurately predict failure of externally supported knitted Dacron femoropopliteal bypass grafts.
abstract: OBJECTIVE
  Our purpose was to evaluate whether a method for quantification of platelet aggregability will predict failure of knitted Dacron femoropopliteal bypass grafts.
  
  
  METHODS
  A numerically derived platelet aggregation (PA) score, based on the aggregation pattern and platelet count, was determined in the 40 patients available for platelet analysis who underwent 53 femoropopliteal bypass grafts with preclotted, 6 mm, externally supported knitted Dacron grafts from 1981 to 1991 (mean follow-up 50 months). The preoperative score was found to remain stable after surgery, enabling the use of postoperative values when preoperative values were not available. The PA score was available in 19 patients (23 grafts) before surgery and 23 patients (30 grafts) after surgery. The following factors were analyzed for predicting graft failure by the Cox proportional hazards regression model: PA score, age, gender, history of smoking, coronary artery disease, hypertension, hyperlipidemia, cerebrovascular disease, diabetes, claudication versus limb salvage, site of the distal anastomosis, previous ipsilateral bypass, and state of the runoff as determined by preoperative angiography.
  
  
  RESULTS
  Of the studied risk factors, the value of the PA score was the most significant predictor of graft closure (p < 0.0001). An increase of 10 units was associated with an increased relative risk of 2.02. Throughout the follow-up period, 15 of 16 grafts remained patent in patients with a PA score of 15 or less, but only 2 grafts out of 17 remained patent in patients with a PA score of 30 or greater.
  
  
  CONCLUSIONS
  These data suggest that the PA score is a potential risk factor for failure of femoropopliteal bypass with externally supported knitted Dacron grafts.
authors.affiliation: Hope Heart Institute, Providence Medical Center, Seattle, WA 98122.
authors.forename: E M
authors.initials: EM
authors.lastname: Saad
authors.forename: S
authors.initials: S
authors.lastname: Kaplan
authors.forename: S
authors.initials: S
authors.lastname: el-Massry
authors.forename: A
authors.initials: A
authors.lastname: Kaplan
authors.forename: K F
authors.initials: KF
authors.lastname: Marcoe
authors.forename: M
authors.initials: M
authors.lastname: Zammit
authors.forename: L D
authors.initials: LD
authors.lastname: Fisher
authors.forename: L R
authors.initials: LR
authors.lastname: Sauvage
mesh_terms: D000244:Adenosine Diphosphate; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical; D000714:Anastomosis, Surgical / Q000379:methods; D001241:Aspirin / Q000627:therapeutic use; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D002951:Citrates / Q000627:therapeutic use; D019343:Citric Acid; D005260:Female; D005263:Femoral Artery / Q000601:surgery*; D005500:Follow-Up Studies; D005544:Forecasting; D006083:Graft Occlusion, Vascular / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects; D010976:Platelet Count; D011093:Polyethylene Terephthalates; D011150:Popliteal Artery / Q000601:surgery*; D011475:Prosthesis Failure; D012039:Regional Blood Flow / Q000502:physiology; D012307:Risk Factors; D014654:Vascular Patency
chemical_list: D002951:Citrates; D011093:Polyethylene Terephthalates; D019343:Citric Acid; D000244:Adenosine Diphosphate; D001241:Aspirin