Collagen biomaterials should be cross-linked in order to prevent biodegradation when they are used as implants. We have compared the cross-linking efficiencies of glutaraldehyde and acyl azide in pericardium. Glutaraldehyde is used currently, but it elicits a cytotoxic effect which reduces the biocompatibility of cross-linked tissue. We have attempted to overcome this problem by developing a cross-linking method that obviates incorporation of foreign agents. Our process involves transformation of free carboxyl groups on collagen into acyl azide groups, which react with free amino groups on adjacent side chains. We have shown that the greatest increase in the thermal stability of collagen, as measured by differential scanning calorimetry, is achieved when tissue swelling is inhibited by the addition of sodium chloride (1 M) during acyl azide formation. Under these conditions, the denaturation temperature (Td) of pericardial collagen treated with acyl azide is raised to 83.4 degrees C and that of tissue treated with glutaraldehyde to 85.1 degrees C. Moreover, acyl-azide-treated tissues have the same resistance as glutaraldehyde-treated tissues to chemical solubilization by cyanogen bromide and to enzymatic digestion by collagenase.
Of 2171 patients who underwent open heart surgery between 1981 and 1986, 41 (1.8%) developed postoperative mediastinitis and were treated by closed irrigation drainage or open chest therapy. Six patients, (mean age 59 years) developed rupture of the right ventricular free wall. The primary procedures were: resection of akinetic fibrous plaque (2), mitral valve replacement (1), coronary bypass grafting (1), removal of a left atrial myxoma (1) and repair of post-infarction rupture of the left ventricle (1). In 2 patients, rupture occurred in the operating theatre during revision of the irrigation drainage. Both patients died after repair. In 4 patients, rupture occurred during coughing. One died before surgery. In the 3 other cases, the defects were repaired either by direct suture (2 patients) or with a pericardial patch (1 patient) with the aid of normothermic extracorporeal circulation. Three days later, a muscular flap (pectoral or dorso-lumbar) was mobilized to protect the mediastinal viscera. All 3 patients are alive and well. When bleeding occurs during treatment of mediastinitis, an immediate exploration with extracorporeal circulation to close the defect should be considered.
The first part of this paper deals with the general anatomy of the postero-septal area of the heart, with particular emphasis on the relationships between the mitral and tricuspid anuli and the right fibrous trigone, between the conducting system and the interatrial septum, and between the right atrium and the posterior superior process of the left ventricle. In the second part, we describe the operative procedure that has been developed for dividing right and left posteroseptal Kent bundles. The key to this technique is the opening of the right atrium along the tricuspid anulus down to the orifice of the coronary ostium; this offers an excellent exposure on the posterior aspect of the septal area, and allows dissection of the sulcus fat pad from the muscular portion of the interventricular septum and the adjacent posterior superior process of the left ventricle down to the level of the mitral anulus. This planned dissection increases the likelihood of interrupting the anomalous pathways without injury to the normal conducting system which remains encompassed within the interatrial septum and the right fibrous trigone.
This study was undertaken to assess the effects of hypothermia and chemical cardioplegia on the functional recovery of hypertrophied non-failing rat hearts subjected to an extended period of global ischaemia. Left ventricular hypertrophy was produced by constriction of the abdominal aorta. Hearts were studied an average of 8 weeks following this procedure. Sham-operated animals served as controls. Twenty-nine isolated isovolumic perfused rat heart preparations were then subjected to 2 h of ischaemic arrest at 15-18 degrees C followed by 45 min of normothermic reperfusion. In one series of hearts (8 sham, 8 hypertrophied), myocardial protection consisted of hypothermia alone. In another series (6 sham, 7 hypertrophied), repeated infusions of cardioplegic solution at 30-min intervals throughout arrest were added to hypothermia. Hypothermia alone resulted in a similar preservation of contractility as evidenced by the recovery of dp/dtmax/left ventricular (LV) systolic pressure after 45 min of reperfusion (91.6 +/- 5.9% of control values in sham vs 78.6 +/- 6.5% in hypertrophied hearts). Conversely, the recovery of compliance was much more impaired in hypertrophied hearts as indicated by a significantly higher percentage of increase in post-ischaemic LV diastolic pressure (DP) (at 45 min of reperfusion: 243.8 +/- 27.5% of control values vs 167.1 +/- 23.8% in sham, P less than 0.05). The addition of cardioplegia improved the preservation of contractility in both groups but its major effect was to normalize the recovery of compliance in hypertrophied hearts so that post-ischaemic LVDP values were no longer different from those recorded in normal hearts (at 45 min of reperfusion: 102.1 +/- 32.8% vs 98.5 +/- 14.2% of pre-ischaemic values respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.