The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Aug 1992
Comparative StudyResponses of human gastroepiploic arteries to vasoactive substances: comparison with responses of internal mammary arteries and saphenous veins.
We examined the responses of human gastroepiploic arteries to histamine, serotonin, and norepinephrine, comparing those of internal mammary arteries and saphenous veins. Fresh specimens of the vessels were obtained intraoperatively from 21 patients. The vessels were suspended in organ chambers to record isometric tensions. ⋯ With the gastroepiploic artery, the responses to norepinephrine and serotonin were similar to those of the internal mammary artery. Histamine induces endothelium-dependent relaxations only, and histaminergic receptors that induce contractions may be absent on vascular smooth muscle cells. These vasoactive properties may contribute to the high patency as a coronary graft.
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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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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.
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J. Thorac. Cardiovasc. Surg. · Aug 1992
Overcoming perioperative spasm of the internal mammary artery: which is the best vasodilator?
After mobilization, vasospasm often reduces flow through the internal mammary artery. An established method of relaxing the artery and increasing flow is to wrap it in a papaverine-soaked swab. To our knowledge the ability of other topical vasodilators to overcome spasm of the internal mammary artery has not been studied clinically. ⋯ Nifedipine and glyceryl trinitrate raised free flow by almost threefold, from 23 (14 to 66) to 71 ml/min (45 to 118) and from 23 (14 to 58) to 62 ml/min (46 to 126), respectively (both p less than 0.001). Sodium nitroprusside, however, with an increase in flow from 26 (10 to 58) to 108 ml/min (46 to 196), 250% over control, proved to be more effective than nifedipine and glyceryl trinitrate (p less than 0.05). We therefore recommend the topical use of sodium nitroprusside to relieve perioperative spasm of the internal mammary artery.
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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.