The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Apr 1993
Cardiac-derived thromboxane A2. An initiating mediator of reperfusion injury?
After crystalloid cardioplegic arrest, cardiac-derived thromboxane A2 may be an important initiating mediator of no-reflow and hemodynamic deterioration during reperfusion because of its potent vasoactive properties. Although previous studies have already documented the increased release of cardiac thromboxane A2 after ischemia, none have studied the effects of cardiac thromboxane A2 on hemodynamics. We therefore tested the ability of cardiac thromboxane A2 to mediate deterioration of coronary flow and functional recovery during reperfusion after global ischemia. ⋯ In relation to the group with cardioplegic solution alone, postischemic aortic flow, coronary flow, cardiac output, and stroke work were all significantly greater (p < 0.05) in the group with the receptor antagonist (aortic flow: 49.5 +/- 2.4 versus 29.4 +/- 3.3 ml/min; coronary flow; 12.4 +/- 1.2 versus 8.5 +/- 1.3 ml/min; cardiac output, 62.0 +/- 2.8 versus 38.0 +/- 4.4 ml/min; stroke work, 12.6 +/- 0.8 versus 7.1 +/- 0.8 cm H2O.ml). Overall, postischemic coronary effluent thromboxane B2 levels were greater than preischemic values (105.6 +/- 12.4 versus 69.6 +/- 9.8, p < 0.05) and treatment with the receptor antagonist did not significantly affect postischemic thromboxane B2 levels (92.0 +/- 7.3 versus 82.3 +/- 15.5, p = not significant). Neither ischemia nor treatment with the receptor antagonist significantly affected heart rate.(ABSTRACT TRUNCATED AT 400 WORDS)
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J. Thorac. Cardiovasc. Surg. · Apr 1993
Acute isovolemic hemodilution and blood transfusion. Effects on regional function and metabolism in myocardium with compromised coronary blood flow.
The use of isovolemic hemodilution to prevent adverse side effects of homologous blood transfusions has increased. The lowest level of hemoglobin that can be tolerated without regional myocardial dysfunction, however, had not been precisely defined for left ventricular myocardium with compromised coronary blood flow. This level was determined in our study in 19 dogs with critical stenosis of the left anterior descending coronary artery during graded isovolemic hemodilution. ⋯ At a mean level of hemoglobin of 6.0 +/- 0.4 gm/dl, marked contractile dysfunction developed in the left anterior descending region: Systolic shortening decreased from 24.2% +/- 2.1% to 17.9% +/- 1.9% (p < 0.01); postsystolic shortening increased from 4.0% +/- 3.0% to 12.2% +/- 3.8% (p < 0.01); and in the left anterior descending region, oxygen consumption decreased. The increase of arterial level of hemoglobin by only 1.9 +/- 0.2 gm/dl restored contractile function in the left anterior descending region, regional oxygen consumption, and oxygen extraction across the left anterior descending region. Moderate isovolemic hemodilution is relatively well tolerated in left ventricular myocardium with compromised coronary blood flow, and hemodilution regional contractile dysfunction induced by hemodilution is reversible by minimal blood transfusion.
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J. Thorac. Cardiovasc. Surg. · Apr 1993
Randomized Controlled Trial Comparative Study Clinical TrialComparison of two aprotinin dosage regimens in pediatric patients having cardiac operations. Influence on platelet function and blood loss.
Only a few studies have reported on the effects of aprotinin in pediatric cardiac surgery, and the correct dose is controversial. In a prospective, randomized study, three groups of children weighing less than 20 kg were investigated. In group 1 (n = 14): aprotinin 20,000 U/kg was given after induction of anesthesia, 20,000 U/kg was added to the prime, and another 20,000 U/kg was given every hour of cardiopulmonary bypass (low-dose regimen). ⋯ Blood loss was similar for all three groups and added up to approximately 28 ml/kg until the first postoperative day. The use of packed red cells was also comparable for the three groups, whereas the use of fresh frozen plasma was highest in group 1 (1680 ml until the first postoperative day). We conclude from this study that aprotinin did not improve platelet function and did nor reduce blood loss or the need for homologous blood transfusion in pediatric cardiac surgery, regardless of whether a low-dose or a high-dose regimen was used.
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J. Thorac. Cardiovasc. Surg. · Mar 1993
Selection of patients for same-day coronary bypass operations.
Between March 15, 1990, and December 31, 1991, we admitted to the Virginia Mason Hospital for isolated coronary bypass operations 175 consecutive patients with chronic, stable angina pectoris who had prior coronary arteriography. One hundred patients were admitted on the same day as their operations, and 75 patients, deemed to be at higher risk, were admitted 1 day before the operation. Postoperative progress of all patients was monitored by means of a clinical pathway form with physiologic and activity measures plotted against postoperative days. ⋯ Patients admitted selectively for same-day coronary bypass are not at risk for an increased number of complications. Although their hospital stay is reduced, the reduction of their hospital charges is minimal. Preoperative admission of patients with comorbidity requiring medical management or with physical incapacity remains justified, and admitting decisions should remain with the operating surgeon, not third parties.
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J. Thorac. Cardiovasc. Surg. · Mar 1993
Prosthetic valve endocarditis. Experience with porcine bioprostheses.
Prosthetic valve endocarditis remains an infrequent but serious complication of cardiac valvular replacement. Prosthetic valve endocarditis was diagnosed in 56 (1.8%) of 3200 patients in whom one or more porcine bioprostheses were implanted between 1975 and 1988. Of the 56 patients with prosthetic valve endocarditis, there were 40 men and 16 women, with a mean age at initial implantation of 57 years (27 to 81 years). ⋯ There was one reoperation for recurrent and residual endocarditis. There was one late death as a result of recurrent prosthetic valve endocarditis. We advocate early diagnosis and aggressive combined medical and surgical treatment before the development of hemodynamic compromise and other characteristic signs when the culprit organisms are Staphylococcus aureus, gram-negative organisms, and Candida albicans.