Effect of induction and reperfusion with warm substrate-enriched cardioplegia on ventricular function.

BACKGROUND: This study tested the hypothesis that induction and reperfusion with warm substrate-enriched (IRWSE) blood cardioplegia improves postoperative left ventricular (LV) function in patients undergoing elective coronary bypass surgery (CABG). METHODS: After giving informed consent, 67 patients scheduled for CABG surgery were randomized to either IRWSE + cold blood (CB) or CB alone. IRWSE cardioplegia consisted of 37 degrees C substrate-enriched (glutamate, aspartate, hyperkalemic) anterograde and retrograde blood cardioplegic solution followed by non-substrate-enriched cardioplegic solution given at 4 degrees C to 8 degrees C. LV function was measured with ventriculograms, volume conductance catheters, echocardiography, and multiple gated (image) acquisition. RESULTS: The end-systolic pressure-volume relationship was improved postbypass in the IRWSE + CB group (CB, 1.5 +/- 0.74 mm Hg/mL vs IRWSE + CB, 2.1 +/- 1.2 mm Hg/mL; p = 0.042). The postoperative ejection fraction (EF%) was better preserved in the CB group (CB, 65 +/- 11.53% vs IRWSE + CB, 58.62 +/- 11.75%; p < 0.04). CONCLUSIONS: Our results demonstrate a transient improvement in LV systolic function in the immediate postbypass period in CABG patients in the IRWSE + CB group. The intraoperative benefits of the IRWSE + CB technique did not persist in the postoperative period.

Effects of dobutamine on hemodynamics and left ventricular performance after cardiopulmonary bypass in cardiac surgical patients.

BACKGROUND: Dobutamine is commonly used to improve ventricular performance after cardiopulmonary bypass. The authors determined the effect of dobutamine on hemodynamics and left ventricular performance immediately after cardiopulmonary bypass in patients undergoing coronary artery bypass graft surgery. METHODS: One hundred patients received sequential 3-min infusions of dobutamine at 0-40 microg x kg(-1) x min(-1) immediately after cardiopulmonary bypass. Ten additional patients who received no dobutamine served as controls. Hemodynamics and left ventricular performance (fractional area change by transesophageal echocardiography, stroke volume index, and thermodilution cardiac index) were measured. Mixed-effects modeling accounted for repeated-measures data and interindividual differences and allowed for potential effects of covariates. RESULTS: Heart rate increased in a dose-dependent manner. The slope of HR versus dobutamine dose was steeper in individuals in whom peak dobutamine dose was not reached compared with that in the remaining individuals; slope decreased 2.71 +/- 0.68% per year of age. Dobutamine affected blood pressure minimally, but slightly decreased pulmonary capillary wedge pressure and central venous pressure. Systemic vascular resistance initially increased with dobutamine 10 microg x kg(-1) x min(-1) and remained constant with larger doses. Dobutamine produced a dose-dependent increase in left ventricular performance, primarily by increasing heart rate, because stroke volume index decreased with dobutamine dose. CONCLUSION: Our results suggest that the response to graded dobutamine infusion in the post-cardiopulmonary bypass period differs from that previously reported. After cardiopulmonary bypass, the dominant mechanism by which dobutamine improves left ventricular performance is by increasing heart rate. Dobutamine affects blood pressure minimally.

Aortic implantation is possible in all cases of anomalous origin of the left coronary artery from the pulmonary artery.

BACKGROUND: Anomalous origin of the left coronary artery from the pulmonary artery (PA) optimally is treated by creation of a multiple coronary system. This study explores the use of aortic implantation employing alternative methods to achieve coronary transfer in all patients, regardless of the site of origin of the anomalous coronary artery, avoiding the problems of bypass grafts and tunnel procedures. METHODS: During the period 1986 to 1994, 11 patients aged 6 months to 8 years (mean age, 2.6 years) underwent repair. Coronary artery origin from the PA included left sinus in 3, posterior in 2, right sinus in 2, intramural aorta with its orifice at the bifurcation of the main and right PA in 1, high left main PA in 1, high at the bifurcation of main and right PA in 1, and anterior in 1. Findings included angina in 4, prior infarctions in 3, ischemia in 7, left ventricular dysfunction in 6, mitral regurgitation in 5, atrial septal defect in 2, and echocardiograms suggestive of endocardial fibrosis in 4. One patient had prior ligation with ventricular dysfunction and collateralization and recanalization. A single patient was asymptomatic. Repair was accomplished by direct transfer using the PA sinus of Valsalva as a button in only 6; tubular reconstruction was used in 4 when the distance was too great to avoid tension; 2 short tubes were constructed with PA wall in 2 of the 3 left sinus origins, whereas 2 long tubes of PA wall were used (1 high on the left side of the main PA and 1 with left anterior descending origin from the anterior sinus of Valsalva in a patient with malrotation [end neo-artery to side aortic reconstruction]); finally, in situ transfer and intraaortic reconstruction (unroofing and anastomosis) was performed in 1 intramural coronary artery. Division of the PA, mobilization of the distal PA, division of the ductus, and direct reanastomosis of the PA was performed in 3 tubular reconstructions, as well as all 6 direct coronary transfers. RESULTS: There were no operative or late deaths. Follow-up of 2 to 100 months (mean, 46 months) revealed no new angina or infarctions, improved function and decreased mitral regurgitation. Echocardiographic and angiographic studies demonstrated patency and prograde flow in the new coronary systems. CONCLUSIONS: Aortic implantation is the treatment of choice for anomalous origin of the left coronary artery. Methods such as direct transfer, tubular reconstruction, and in situ transfer make such implantation possible in all patients regardless of the site of coronary origin, distance from the aorta, or coronary artery configuration.

Light and electron microscopical immunohistochemical localization of the small proteoglycan core proteins decorin and biglycan in human knee joint cartilage.

The distribution of decorin and biglycan was investigated at the light and electron microscopical level in adult human articular cartilage. In general, the amount of decorin and biglycan was found to decrease with the depth of the layer of the cartilage. Decorin was found in the interterritorial matrix where most of the collagen is located. This fits in well with the assumption that decorin may modulate collagen metabolism. Biglycan was found next to the chondrocytes in the pericellular matrix and is assumed to be responsible for cellular activities. At the ultrastructural level, decorin was localized in the interterritorial matrix and in vesicles in chondrocytes. Biglycan was found, usually though not exclusively in the pericellular matrix. Both small proteoglycans were detected close to and on the collagen fibres and also associated with the more globular structures of the matrix between the fibrils. A double-staining approach revealed that the two molecules could be located along the same collagen fibril. However, staining for biglycan and decorin was not observed simultaneously within the same region of the fibre.