Infective endocarditis was initially described in the early 16th century and only methodically reviewed after the 19th century when Osler gave the drive to the Royal College of Physicians in 1885 through his contribution. The last 25 years has not shown much change in the mortality from infective endocarditis (IE) despite diagnostic and therapeutic advances. The current in-hospital mortality rate for patients with IE is 15% to 20%, with 1-year mortality approaching 40%. The morbidity associated with infective endocarditis includes valvular incompetence, embolization, cerebrovascular accidents and congestive heart failure and this has influenced the surgical options to a great extent. The EuroSCORE II is the current model available for predicting the early mortality after cardiac surgery. HYPOTHESIS: Infective endocarditis has a high risk for mortality due to certain risk factors and the currently available EuroSCORE II model may not predict early mortality accurately and may not be suitable for our patient population. OBJECTIVES: To evaluate the major risk factors for adverse short and long term outcomes in patients with active native valve infective endocarditis needing cardiac surgery, and to validate the EuroSCORE II in our cohort of patients. PATIENTS AND METHODS: A retrospective review will be undertaken on patients with infective endocarditis requiring cardiac surgery from 2000-2012 at the Christian Barnard Division of Cardiothoracic surgery (Groote Schuur Hospital, UCT Private Academic Hospital) and follow-up with respect to mortality, re-operation and major adverse cardiac events, as well as an evaluation of the validity of the EuroSCORE II. DATA COLLECTION AND ANALYSIS: The standardized data extraction form in the appendix will be used for extracting data from various databases and telephonic interviews. Data will be analyzed using STATA to determine the most significant predictors of adverse outcome and conducting Kaplan Meier actuarial analysis for early and late survival and freedom from adverse events. The EuroSCORE II will be evaluated and validated to our cohort of patients.

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Introduction: Intensive research over the last six decades has resulted in minimal improvement in vascular graft development. Small animal models are the first line of species exposed to vascular graft implantation and invasive monitoring of experimental graft patency may contribute to pain, suffering, higher cost and earlier sacrifice. Non-invasive ultrasonographic evaluation of vascular implants during the conduction of animal studies allows for chronic follow-up with multiple assessments. This study aims to apply and endorse the utilization of ultrasound as a less invasive diagnostic method in determining patency of vascular grafts in units where imaging modalities like Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) are not readily available. Methods: Pre-operative control ultrasound evaluation of the ejection fraction, aortic diameter and aortic velocity were conducted on Wistar rats (250-350g). Infra-renal aortic vascular graft implantation was then performed, with 8 rats receiving straight (1.8mm ID, 18mm length) expanded polytetrafluoroethylene (ePTFE) grafts, while 12 rats received a long (1.8mm ID, 100mm length) looped ePTFE conduit with a sealed mid-graft (10mm length) section. Ultrasonography was conducted on days 1, 3, 7 and weeks 4, 8 and 12 post operatively. Grafts were explanted if there was any ultrasonographic evidence of occlusion or at twelveweek termination of the study. Explant was preceded by angiography and followed by histological assessment of the grafts for patency. Results: Three of the looped and all 8 of the straight grafts were patent at the 12 week explant time point, as correctly assessed by ultrasound and confirmed by angiography and histology. Three of the nine occluded looped grafts were explanted at eight weeks due to early ultrasonographic detection of occlusion; the remaining 6 were explanted at twelve weeks. There were two false positive results, which were incorrectly assessed as patent at twelve weeks of implantation on ultrasonographic evaluation, but confirmed to be occluded on angiography at explant. The results of ultrasonography evaluation of implanted infra-renal vascular grafts had a high specificity of 100% with a sensitivity of 78%. The outcome of the results between ultrasound and angiography corresponded in 18 out of 20 vascular grafts, with a calculated positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 85%. 4 Conclusion: Ultrasound is easily available and a non-invasive diagnostic modality allowing for safe and reliable results, which may be repeated at different time frames following vascular implants in small animal models. Ultrasonographic limitations exist, emphasizing the need for an experienced operator with adequate knowledge and training. Its use may be complicated by tortuous geometries of vessels, which is technically more challenging to evaluate with ultrasound than with imaging techniques like CT and MRI. It does, however, add information without additional loss of life or increased use of animal numbers. Ultrasound is an essential additive diagnostic tool for chronic follow-up and evaluation of vascular graft implants.

This study was designed to investigate the role of adenosine, an endogenous cardioprotectant agent, without high potassium and as cardioplegic additive to high potassium solutions. Adenosine cardioplegia and potassium cardioplegia supplemented by adenosine (K + ADO) were investigated in terms of hemodynamic, metabolic and ultrastructural recovery in the isolated rat heart and in the in-vivo baboon model during periods of global myocardial ischemia, simulating the clinical situation during open heart surgery. The results obtained in both models show that adenosine improved postischemic hemodynamic function when used without high potassium cardioplegia. The combination of adenosine and high potassium was less effective in both models in terms of hemodynamic recovery; however, improved rhythm stability and coronary vasodilatation were still present. In addition adenosine alone was able to induce fast electromechanical arrest in the isolated rat heart. However, failure of even high concentrations of adenosine to limit ventricular fibrillation in the baboon exclude its use as cardioplegic agent on its own without additional interventions. It appears likely that adenosine without high potassium is cardioprotective via activation of A₁ receptors and opening of ATP-sensitive potassium channels, a mechanism which is probably non-functional in a high potassium environment. In view of the limited cardioprotection achieved with the combination of adenosine and high potassium further studies should aim for additional interventions to induce cardioplegia with adenosine and normokalemic solutions.

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This thesis investigated the potential of synthetic polyethylene glycol (PEG) hydrogels for restoration of biomechanical integrity and for controlled cardiac release of drugs. ... The aim of this study was to directly compare the effect of injecting an enzymatically degradable polyethylene glycol (PEG) hydrogel into the myocardium immediately or seven days after permanent ligation of the left anterior descending artery in rats on pathological remodeling.

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Includes bibliographical references. / A retrospective study was done at Red Cross Children's Hospital, Rondebosch, Cape Town in which two separate case-matched groups of children undergoing different surgical closure techniques for their isolated perimembranous ventricular septal defects were compared. Group I consisted of 77 children who had their VSDs closed between 1987 to 1990, mainly with a double velour dacron patch using interrupted alternating 5.0 silicone coated braided polyester suture ( Ticron®) and 5.0 polypropylene (Prolene®) pledgetted sutures (n=71). Five patients in Group I had bovine pericardium used and 1 patient's VSD was closed by a direct suture technique. Group II consisted of 93 children operated on between 1995 to 1998, and had their VSDs closed with a 0.6% glutaraldehyde-treated autologous pericardial patch using 5.0 polypropylene suture material in a continuous horizontal mattress suture without pledgets. Surgical time, discharge echocardiograms and follow up records were reviewed to assess the incidence of complications, reoperation or residual VSD needing further follow up.

There is a significant need for small diameter vascular grafts to be used in peripheral vascular surgery; however autologous grafts are not always available, synthetic grafts perform poorly and allografts and xenografts degenerate, dilate and calcify after implantation. We hypothesized that chemical stabilization of acellular xenogenic arteries would generate off-the-shelf grafts resistant to thrombosis, dilatation and calcification. To test this hypothesis, we decellularized porcine renal arteries, stabilized elastin with pentagalloyl glucose and collagen with carbodiimide/activated heparin and implanted them as trans- position grafts in the abdominal aorta of rats as direct implants and separately as indirect, isolation-loop implants. All implants resulted in high patency and animal survival rates, ubiquitous encapsulation within a vascularized collagenous capsule, and exhibited lack of lumen thrombogenicity and no graft wall calcification. Peri-anastomotic neo-intimal tissue overgrowth was a normal occurrence in direct implants; however this reaction was circumvented in indirect implants. Notably, implantation of non- treated control scaffolds exhibited marked graft dilatation and elastin degeneration; however PGG significantly reduced elastin degradation and prevented aneurismal dilatation of vascular grafts. Overall these results point to the outstanding potential of crosslinked arterial scaffolds as small diameter vascular grafts.

Includes abstract. Includes bibliographical references.