Circulation
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Among 48 consecutive patients with pretransplant pulmonary vascular resistance (PVR) greater than 4 Wood units, 38 patients underwent orthotopic heart replacement (OHT), and the remaining 10 received a graft in a heterotopic position (HHT). The OHT recipients were smaller (63 vs. 73 kg, p less than 0.05) and received a larger donor heart (donor-recipient, 109% vs. 79%, p less than 0.001) with a shorter graft ischemic time (108 vs. 139 minutes, p less than 0.05) than HHT recipients, reflecting patient selection and surgical complexity. Comparison between the hospital survivors and nonsurvivors identified the selection of HHT and graft ischemic time in excess of 150 minutes as potent risk factors. ⋯ The higher the preoperative PVR value, the more substantial the reduction observed, resulting in normalization of PVR for all survivors. The incidence of early graft failure was similar between the groups, but HHT recipients frequently developed pulmonary complications and infection, resulting in a 30% hospital survival in contrast to 71% in OHT recipients (p less than 0.05). The results suggest that transplant candidates with pulmonary hypertension might better be treated by OHT with an oversized, on-site, viable donor heart than by HHT.
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Skeletal muscle grafts can be used to mechanically assist the failing heart. In 13 mongrel dogs, latissimus dorsi muscle was preconditioned in situ for 6-8 weeks. Biopsy samples of the muscles were obtained for histochemical analysis. ⋯ Thus, chronic stimulation of skeletal muscles induces fiber transformation and increases resistance to fatigue and force development. Cardiomyoplasty, on the other hand, improves ventricular function in the presence of acute heart failure. This surgical technique represents an alternative method of treatment for advanced myocardial failure.
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A method is presented for maintaining aortic flow by mechanical means during intractable cardiac arrest. A spherical balloon was inserted into the left ventricle while the usual intra-aortic balloon was introduced into the thoracic aorta. Ventricular fibrillation was induced by direct current. ⋯ The intraventricular balloon capacity varied from 40 to 110 ml (six dogs weighing 16-24 kg) while the intra-aortic balloon capacity was 20 ml. An optimal pumping rate of 75 beats/min maintained an aortic flow of 0.9-1.5 ml/beat/kg and a mean pressure into the brachiocephalic trunk of 110 +/- 12.5 mm Hg (mean +/- SD). These experimental data indicate that an easily applied mechanical device system (needing no extracorporeal circulation) may be used to bridge the time between intractable cardiac arrest and implantation of an artificial heart or transplantation.
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We investigated the release of endothelium-derived relaxing factor (EDRF) in response to serotonin and histamine in the human internal mammary artery and saphenous vein. The arteries and veins were obtained intraoperatively and were suspended in organ chambers to record isometric tension. In mammary arteries, histamine (10(-8) to 3 X 10(-6) M) induced relaxations in rings with (70 +/- 5%, IC50, 6.5 +/- 0.2) but not without endothelium (p less than 0.005 for rings with compared with those without endothelium, n = 7-10). ⋯ The endothelium inhibited the maximal contraction to serotonin in arteries (p less than 0.034) but not in veins. Thus, EDRF protects against contractions induced by histamine and serotonin in the mammary artery but not in the saphenous vein. This may be important for improved graft function and patency of the artery compared with that of the vein.
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Deep-hypothermic cardiopulmonary bypass with selective cerebral perfusion (SCP) was used in 34 consecutive patients with aneurysms involving the aortic arch or the adjacent part of the aorta. The ages ranged from 25 to 79 years (mean, 56 years). Atherosclerotic aneurysms were present in 14 patients, dissecting aortic aneurysms in 16, and other lesion types in four. ⋯ Neurological sequelae occurred in one patient (cerebral infarction), but significant respiratory and hemorrhagic problems were not encountered. For the SCP protocols, we advise that perfusion pressures at bilateral superficial temporal arteries be kept at approximately 50 mm Hg and that venous oxygen saturation of the superior vena caval line or internal jugular vein be kept at above 90%. With appropriate monitoring, this method can be performed in aortic arch or related surgeries with low morbidity results.