Impact of Clopidogrel Loading for Coronarography on Bleeding After Urgent First Time CABG.

BACKGROUND: Excessive bleeding impairs outcome after coronary artery bypass grafting (CABG). Clopidogrel in combination with aspirin, given before percutaneous coronary intervention, have become the standard for stent thrombosis prevention. Some premedicated patients, however, are found to need surgical treatment, thus platelet inhibition caused by clopidogrel becomes a concern for post operation major bleeding. AIMS: This study was designed to evaluate the impact of preoperative clopidogrel on bleeding and outcomes after coronary artery bypass graft surgery (CABG). METHODS: The study represent a observational retrospective analysis of collected data. The follow up of 223 treated with clopidogrel and aspirin and 77 patients not receiving treatment with platelet antagonist 7 days before CABG are analyzed. RESULTS: The groups were comparable in age, gender, body surface area, preoperative hematocrit, preoperative prothrombin time and prior myocardial infarction. The clopidogrel group had higher12h and 24h mean chest tube output (at 12h mean 519.7ml vs 353.1 ml, p < 0.05, at 24h mean 756.6 ml vs 563.5 ml, p<0.05). Moreover, reoperation for bleeding was 4.5-fold higher in the clopidogrel group (5.9% vs. 1.3%, p <0.01), and more transfusions of red blood cells (3.23U vs 2.6 U, p<0.05), platelets (1.53U vs 1.23U, p<0.01) and fresh frozen plasma (0.84U vs 0.36 U, p<0.01). The clopidogrel group also showed a longer mechanical ventilation time (16.9h vs 12.9 h p = 0.03) and trend towards more prolonged stay in ICU (2.08 days vs 1.7 days p= 0.048). CONCLUSIONS: Clopidogrel in combination with aspirin before CABG is associated with higher postoperative bleeding, exposure to blood products and morbidity. These findings raise concern regarding the routine administration of clopidogrel before anticipated but undecided coronary stent implantation.

Effect of Aneurysm and Bicuspid Aortic Valve on Layer-Specific Ascending Aorta Mechanics.

BACKGROUND: Previous studies have not examined the participation of intimal, medial, and adventitial layers in providing mechanical strength to the ascending thoracic aortic aneurysm (ATAA) wall compared with the nonaneurysmal aorta. In this study we compared the mechanical properties of intact wall and its layers among ATAAs and nonaneurysmal aortas, with explicit consideration of the effects of valve morphology; that is, bicuspid aortic valve (BAV) versus tricuspid aortic valve (TAV), and aortic quadrant. METHODS: Whole ATAAs were taken from patients undergoing elective repair and nonaneurysmal aortas from age-matched autopsy subjects. These were cut into 2 circumferential and longitudinal tissue strips for the intact wall and its layers per quadrant, permitting examination of the aortic wall as a multilayered structure. Tissue underwent tensile testing for determination of failure properties. RESULTS: Intact wall and layer-specific failure stretches (ie, extensibilities) were significantly greater in nonaneurysmal and BAV-ATAA than in TAV-ATAA, unaccounted for by elastin/collagen content changes. Intact wall failure stress (ie, strength) was significantly greater in BAV-ATAA than in TAV-ATAA, in analogy with medial failure stress. Failure stress and stretch associated negatively with age in most subject groups, layers, and intact wall, but failure stretch correlated positively with residual stretch (ie, structural bonds between layers). CONCLUSIONS: No mechanical vulnerability of BAV-ATAA was found, corroborating current conservative guidelines regarding the management of bicuspid aortopathy. Weakening and added vulnerability was found in patients with valvular deficiency, aortic root aneurysm, hypertension, and hyperlipidemia. Aging led to increased susceptibility to dissection initiation or full rupture, or both, in both patient classes.