The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Aug 1992
Comparative StudySimilar endothelium-dependent relaxation, but enhanced contractility, of the right gastroepiploic artery as compared with the internal mammary artery.
The right gastroepiploic artery is an alternative coronary bypass graft. The excellent graft function of the internal mammary artery has been related to its physiologic properties, particularly to endothelial function. Isolated artery rings were suspended in organ chambers for recording of isometric tension. ⋯ The relaxation to the nitric oxide donor SIN-1 was identical in the two arteries. Thus the right gastroepiploic artery exhibits better contractility than the internal mammary artery but comparable endothelium-dependent and endothelium-independent relaxations. The good endothelial function of the gastroepiploic artery might be important for graft function and patency, whereas the enhanced contractility may facilitate vasospasm, especially in the presence of high circulating levels of catecholamines.
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J. Thorac. Cardiovasc. Surg. · Aug 1992
Comparative StudySuperior qualities of University of Wisconsin solution for ex vivo preservation of the pig heart.
The components of the University of Wisconsin solution have the potential to enhance and extend heart preservation. We have evaluated University of Wisconsin solution by comparing it with St. Thomas' Hospital cardioplegic solution in the isolated pig heart subjected to 8 hours of ischemia at 4 degrees C (n = 6 in each). ⋯ Myocytes from hearts receiving University of Wisconsin solution, unlike those given St. Thomas' Hospital solution, showed relaxed myofibrils with prominent I-bands. We conclude that University of Wisconsin solution has the potential to improve the preservation of the heart and possibly prolong the ischemic period in clinical cardiac transplantation.
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Between December 1982 and March 1990, 65 patients with active infective endocarditis underwent cardiac operations. Their mean age was 28.6 years (range 1 to 65 years). The most common infecting organisms were staphylococcus (33.8%), streptococcus (18.5%), and brucella (16.9%); 11 patients (16.9%) had cultures negative for infection. ⋯ There was one late death. Early operation should always be considered in active infective endocarditis, especially when a prosthetic valve is involved or the infecting organism is staphylococcal or fungal. The disclosure of moderate to large vegetations by two-dimensional echocardiography is an indication for operation.
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J. Thorac. Cardiovasc. Surg. · Aug 1992
Myocardial oxygen consumption of fibrillating ventricle in hypothermia. Successful account by new mechanical indexes--equivalent pressure-volume area and equivalent heart rate.
We studied the effects of cardiac hypothermia on myocardial oxygen consumption of a fibrillating ventricle and evaluated whether myocardial oxygen consumption of a fibrillating ventricle in hypothermia can be accounted for by new mechanical indexes: equivalent pressure-volume area and equivalent heart rate in the isolated cross-circulated canine heart preparation. Equivalent pressure-volume area is the area that is surrounded by a horizontal pressure-volume line at the pressure of a fibrillating ventricle and the end-systolic and end-diastolic pressure-volume relations in the beating state in the pressure-volume diagram. Equivalent pressure-volume area is an analog of the pressure-volume area of a beating heart and has been proposed to be a measure of the total mechanical energy of a fibrillating ventricle. ⋯ The myocardial oxygen consumption-equivalent pressure-volume area relation during ventricular fibrillation in hypothermia was highly linear, with a correlation coefficient of 0.90 (mean). The relation between estimated and directly measured myocardial oxygen consumption values of a fibrillating ventricle in hypothermia was highly linear (r = 0.98), and the regression line (y = 0.80x + 0.48) was close to the identity line in the working range. Therefore we conclude that equivalent pressure-volume area is the primary determinant of myocardial oxygen consumption during ventricular fibrillation in hypothermia, and myocardial oxygen consumption of a fibrillating ventricle in hypothermia can be accounted for by the combination of equivalent pressure-volume area and equivalent heart rate as in normothermia.
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J. Thorac. Cardiovasc. Surg. · Aug 1992
Transient hypocalcemic reperfusion does not improve postischemic recovery in the rat heart after preservation with St. Thomas' Hospital cardioplegic solution.
We used the isolated perfused working rat heart to investigate the effects of transient hypocalcemic reperfusion after cardioplegic arrest with the St. Thomas' Hospital cardioplegic solution and 25 minutes of global normothermic (37 degrees C) ischemia. Hearts were reperfused (Langendorff mode) transiently (20 minutes) with solutions containing various concentrations of calcium; this was followed by 30 minutes of reperfusion with standard (1.4 mmol/L, the physiologic concentration) calcium buffer (10 minutes in the Langendorff mode and 20 minutes in the working mode). ⋯ Despite this, transient (10 minutes) hypocalcemic (0.5 mmol/L) reperfusion did not improve recovery. Finally, studies were undertaken with a longer duration of ischemia (40 minutes), and although recovery of cardiac output in the hypocalcemic group (0.5 mmol/L for 10 minutes) tended to be higher than in the control group (29.7% +/- 4.8% versus 18.5% +/- 4.9%, respectively), statistical significance was not achieved. We conclude that in these studies transient hypocalcemic reperfusion did not afford any additional protection over and above that afforded by cardioplegia alone.