The Annals of thoracic surgery
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Five patients undergoing cardiopulmonary bypass (CPB) procedures were extensively monitored because of anticipated high risk for neurological complications. Arterial blood pressure (BP), central venous pressure, and epidural intracranial pressure (EDP) were continuously recorded throughout CPB; thus, information on the cerebral perfusion pressure (CPP) was also continuously available (CPP = BP - EDP). Cerebral electrical activity was recorded by a cerebral function monitor. ⋯ During CPB with constant temperature, hematocrit, and PaCO2, the effect of changes in CPP on MCA flow velocity was recorded and analyzed. During nonpulsatile, moderately hypothermic (28 degrees to 32 degrees C), low-flow (1.5 L/min/m2) CPB, there was no evidence of cerebral autoregulation, with CPP levels ranging from 20 to 60 mm Hg. The CO2 reactivity, however, was clearly present and in the range of 1.9 to 4.1%/mm Hg, indicating that there was a dissociation between cerebral autoregulation and CO2 reactivity under these circumstances.
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To identify possible risk factors for the occurrence of stroke during coronary artery bypass grafting (CABG), the cases of 3,279 consecutive patients having isolated CABG from 1974 to 1983 were reviewed. During this period, the risk of death fell from 3.9% to 2.6%. The stroke rate, however, fell initially but then rose from 0.57% in 1979 to 2.4% in 1983. ⋯ A case-control study involving all 56 stroke victims and 112 control patients was used to identify those risk factors significantly associated with the development of stroke in univariate analysis: increased age (63 versus 57 years in stroke patients and controls, respectively; p less than 0.0001); preexisting cerebrovascular disease (20% versus 8%; p less than 0.03); severe atherosclerosis of the ascending aorta (14% versus 3%; p less than 0.005); protracted cardiopulmonary bypass time (122 minutes versus 105 minutes; p less than 0.005); and severe perioperative hypotension (23% versus 4%; p less than 0.0001). Other variables not found to correlate with postoperative stroke included previous myocardial infarction, hypertension, diabetes mellitus, lower extremity vascular disease, preoperative left ventricular function, and intraoperative perfusion techniques. Elderly patients who have preexisting cerebrovascular disease or severe atherosclerosis of the ascending aorta or who require extensive revascularization procedures have a significantly increased risk of postoperative stroke.
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Sixty-seven operations were performed in 59 patients for aneurysmal disease occurring after previous operations involving the ascending aorta and transverse aortic arch. The initial aortic pathological condition included the following: fusiform aneurysm due to medial degenerative disease in 34 patients, 12 of whom had Marfan's syndrome; aortic dissection in a previously undilated aorta in 23; and aneurysm persisting or occurring after brachiocephalic bypass in 2. One of the latter had an aneurysm because of aortitis. ⋯ The entire aorta was replaced in 3, thoracoabdominal segments in 9, and the abdominal aorta in 1. Of the 59 patients, 49 (83%) were early survivors and 40 (68%) were alive on January 1, 1985. Principles of therapy that may have prevented the complications leading to reoperation include aneurysm replacement at the time of aortic valve replacement and coronary artery bypass; total replacement of the ascending aorta and aortic valve in patients with Marfan's syndrome; the same procedure or aortic valve replacement and separate graft replacement in patients with non-Marfan's medial degenerative disease; ascending aortic replacement in all patients with dissection combined with valve resuspension, aortic valve replacement, or composite valve graft depending on the involvement of the aortic sinuses and the presence of aortic insufficiency.
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An air gun pellet cardiac injury, in which there was penetration through the right ventricle, interventricular septum, and anterior papillary muscle and ejection from the left ventricle, is described. The pellet embolus was removed from the left popliteal artery with restoration of flow. The particular implications of pellet embolization are discussed and contrasted with those of bullet embolism.
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Placement of a right ventricle-pulmonary artery conduit (18- or 20-mm grafts) made of Gore-Tex without a prosthetic valve was undertaken in 6 patients ranging in age from 8 1/2 to 32 years. Three patients had tetralogy of Fallot with pulmonary atresia, and the other 3 had transposition of the great vessels, ventricular septal defect, and pulmonary obstruction. Pulmonary pressure was low in all patients. The technique for implantation of this valveless, noncrimped type of prosthesis is described.