Effect of preexcisional heparin anticoagulation on excised canine vein and artery prostanoid production

The effect of heparin, administered prior to vessel dissection and excision, on the luminal release of prostanoids from an excised vessel was assessed. Eight adult mongrel dogs underwent removal of the jugular vein and carotid artery on one side, followed by intravenous administration of heparin sodium (150 IU/kg) and subsequent removal of these same vessels from the contralateral neck. The excised vessels were perfused in an ex vivo system with Hanks' balanced salt solution for five consecutive 15-min periods. Prostacyclin release (measured as 6-keto-PGF1[alpha]) and thromboxane A2 (measured as thromboxane B2) release into the perfusate were quantitated by radioimmunoassay. Vessel segments were studied with and without first period thrombin stimulation (2 U/ml) and with arachidonic acid (4 [mu]g/ml) stimulation during the last perfusion period. Vein segments following heparin administration exhibited greater prostacyclin production than veins not exposed to heparin. This effect did not occur in arteries. Heparin did not influence thromboxane A2 release. Luminal endothelial cell coverage was not affected by the presence or absence of heparin. Thus heparin anticoagulation prior to dissection and excision of a vein, may enhance early preservation of its endothelial cell function as evident by increased luminal release of prostacyclin.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27928/1/0000352.pd

Anticoagulant effects of protamine sulfate in a canine model,

Protamine sulfate is considered a weak anticoagulant, yet little is known concerning the mechanism of this effect or its relation to prior heparin exposure. This investigation defined the influence of increasing doses of protamine, with and without prior heparin anticoagulation, on the activated clotting time (ACT), thrombin clotting time (TCT), prothrombin time (PT), partial thrombosplastin time (PTT), fibrinogen level, platelet count, and platelet aggregation to ADP in dogs (n = 8). Four doses of intravenous protamine sulfate (1.5, 3.0, 6.0, and 15.0 mg/kg) were studied in each animal, with at least 5 days between individual studies. Four dogs received heparin, 150 IU/kg 10 min prior to protamine sulfate administration, and four dogs received protamine sulfate alone. Protamine sulfate caused anticoagulation, both in the presence and absence of heparin, with significant changes occurring in the ACT, PTT, platelet count, and platelet aggregation. Relevant changes did not occur in the TCT, PT, or fibrinogen levels. Platelet effects were capable of causing bleeding with standard or excess use of protamine sulfate, especially if platelet numbers were already decreased, as might occur in surgical procedures where thrombocytopenia commonly accompanies major blood loss and replacement. The ACT, reflecting both the coagulation cascade and platelet function, was the test most profoundly affected by protamine overdosage, and therefore may be misleading as a measure of protamine reversal of heparin. The TCT, which is sensitive to heparin anticoagulation but not protamine-induced anticoagulation, should be more accurate in differentiating inadequate heparin reversal from the effects of excess protamine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27223/1/0000227.pd

Improving the outcomes of carotid endarterectomy: Results of a statewide quality improvement project

AbstractObjective: The purpose of this study was to establish the statewide outcomes for carotid endarterectomy (CEA) and to facilitate improvement in outcomes through feedback, peer discussion, and ongoing process and outcome measurement. Methods: The Medicare Part A claims files were used to identify all Medicare patients undergoing CEA in Iowa during two 12-month time periods (January 1994–December 1994 and June 1995–May 1996). Medical record abstraction was used to obtain surgical indications, perioperative care process, and outcome information. Confidential reports were provided to each hospital (N = 30) where the procedure was performed. Surgeons performing the procedure (N = 79) were invited to meetings to discuss care process variation and outcomes. Voluntary participation was solicited in a standardized program of ongoing hospital-based data collection of CEA process and outcome data. Results: The statewide combined stroke or mortality rate decreased from 7.8% in 1994 to 4.0% in the 1995 to 1996 time period (P <.001). Fourteen hospitals, accounting for 74% of the statewide cases, participated in ongoing data collection. The combined stroke or mortality rate in these hospitals decreased significantly (P <.05) over time from 6.5% (1994) to 3.7% (1995-1996) to 1.8% (June 1997–May 1998). The use of intraoperative assessment of the operative site (20% in 1994, 46% in 1997-1998) and patch angioplasty (14% in 1994, 30% in 1997-1998) increased significantly during this time in the participating hospitals. Conclusions: Confidential feedback of outcome and process data for CEA may lead to change in perioperative care processes and improved outcomes. Standardized community-based outcome analysis should become routine for CEA to ensure that optimum results are being achieved. (J Vasc Surg 2000;31:918-26.

Multistate improvement in process and outcomes of carotid endarterectomy

AbstractObjectivesThe purpose of this study was to assess the effect of community-wide performance measurement and feedback on key processes and outcomes of carotid endarterectomy (CEA).MethodsComplete medical record (hospital chart) review for indications, care processes, and outcomes was performed on a random sample of Medicare patients undergoing CEA in 10 states (Arkansas, Georgia, Illinois, Indiana, Iowa, Kentucky, Michigan, Nebraska, Ohio, Oklahoma) during baseline (Jun 1, 1995 to May 31, 1996) and remeasurement (Jun 1, 1998 to May 31, 1999) periods. In addition to review of the index hospital stay, hospital admissions within 30 days of the procedure were reviewed and the Medicare enrollment database queried to identify out-of-hospital deaths, to determine 30-day outcome results. The baseline data by state were provided to the Medicare Quality Improvement Organizations (QIOs) in the respective states, and quality improvement initiatives were encouraged.ResultsWe reviewed 9945 primary CEA alone procedures, 236 CEA and coronary artery bypass grafting (CABG) procedures, and 380 repeat CEA operations during the baseline period (B), and 9745 primary CEA alone procedures, 233 CEA and CABG procedures, and 401 repeat CEA operations during the remeasurement period (R). There was a significant decrease in the combined event rate (30-day stroke or mortality) for CEA alone procedures between baseline and remeasurement (B, 5.6%; R, 5.0%). A decrease occurred in each of the indication strata; transient ischemic attack or stroke (B, 7.7%; R, 6.9%), nonspecific symptoms (B, 5.9%; R, 5.4%), and no symptoms (B, 4.1%; R, 3.8%). The combined event rate also decreased for CEA and CABG (B, 17.4%; R, 13.3%) and repeat CEA operations (B, 6.8%; R, 5.7%). The remeasurement period state-to-state variation in combined event rate for CEA alone ranged from 2.7% (Georgia) to 5.9% (Indiana) for all indications combined, from 4.4% (Georgia) to 10.9% (Michigan) in patients with recent transient ischemia or stroke, from 1.4% (Georgia) to 6.0% (Oklahoma) in patients with no symptoms, and from 3.7% (Georgia) to 7.9% (Indiana) in patients with nonspecific symptoms. There were significant increases in preoperative antiplatelet administration (62%-67%; P < .0001) and patching (29%-45%; P = .05) from baseline to remeasurement in the CEA alone subset. Preoperative antiplatelet administration and patching were associated with improved outcomes in the combined baseline and remeasurement data.ConclusionsCommunity-wide quality improvement initiatives with performance measurement and confidential reporting of provider level data can lead to improvement in important care processes and outcomes. There is considerable variation between states in outcome and process, and thus continued room for improvement. Quality improvement projects that include standardized confidential outcome reporting should be encouraged. Preoperative antiplatelet therapy administration and patching rates should be considered as evidence-based performance measures