Browsing by Subject "Cardiothoracic Surgery"
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- ItemOpen AccessAdenosine and its role in cardioplegia : experimental evaluation in the isolated rat heart and in an-vivo primate model(1997) Boehm, Dieter Hermann; Opie, Lionel H; Reichart, BThis 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.
- ItemOpen AccessInvestigation of synthetic hydrogels as therapy for myocardial infarction(2011) Kadner, Karen; Davies, NeilThis 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.
- ItemOpen AccessLeft ventricular submitral aneurysms(2007) Du Toit, Henning; Hewitson, John; Lawrenson, JohnRetrospective institutional review of the pathology, aetiology classification and surgical management of left ventricular submitral aneurysms (LVSMA). These aneurysms are a well recognized but relatively rare disease found commonly in patients from African ancestry. The series comprises 20 consecutive patients treated surgically at three institutions from 1985 to 2002. Natural history, clinical presentation, histo-pathological findings, suspected aetiology, operative techniques, along with a discussion of the condition is presented. There were 10 female and 10 male patients and the mean age was 17+-6 (range 8-34) years. Patients were grouped as to the degree of posterior mitral annulus involvement by the aneurysm. In Group I, (n=12) a single aneurysm neck was found. In Group II, (n=3) multiple necks and in Group III, (n=5) involvement of the entire posterior annulus by teh aneurysm was found. Mean age in Group III (29 +/-5 years) was older than that of Groups I and II (15.5 +/- 4 years) suggesting a progressive nature of these aneurysms to enlarge. Clinically patients were in New YOrk Heart Association (NYHA) class I-IV. An intra-cardiac surgical approach was used in 11, extra-cardiac approach in two and a combined approach in seven patients. Mitral valve repair was attempted in 14 patients, with two intra-operative mitral valve repair failures. Failure to control the aneurysm neck (n=2) and failure of mitral valve repair (n=2) resulted in subsequent re-operation. There was no operative mortality. Histology of the aneurysm tissue suggested co-existing rheumatic heart disease in two, tuberculosis in four and infective endocarditis in two. Unknown or congenital disease was postulated in nine patients. Although LVSMA are thought to be congenital, 8 out of 20 patients (40%) had evidence of co-existent inflammatory pathology. The etiology of LVSMA remains uncertain. Many are thought to be congenital, but the findings in this study strongly support the view that rheumatic disease, chronic infections and malnutrition also play a role. A new classification is proposed based on the pathological findings. Involvement of the entire annulus in the older patients suggests a possible progressive nature of the disease. Surgery should be the difinitive therapy in all patients. Surgical approach must be individualized but the intra cardiac approach is suitable for the surgical repair in most cases. Success in mangement is dependent on the appropriate understanding of the relationship between aneurysm and valve.
- ItemOpen AccessLong term outcome and the validity of EuroSCORE II in native-valve surgery for active endocarditis in a South African cohort(2015) Koshy, Jithan Jacob; Zilla, Peter; Brink, Johan G; Engel, Mark EInfective 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.
- ItemOpen AccessLung volume reduction surgery : the Groote Schuur experience(2000) Walther, G B; De Groot, KM; Bateman, EDFrom recent statistics (79,59) it has been concluded that COPD is the most common lung disease in the United States affecting almost 16 million people. The mortality is rising, COPD is the fourth most common cause of death in USA after myocardial infarctions, cancer and stroke (91). COPD is clearly under diagnosed in the early stages (101). Early smoking cessation would have an enormous impact on the progression of the disease (7,24,25,58,106).
- ItemOpen AccessMechanical aortic valves and the small aortic root(2002) Stemmet, FrancoisIncludes bibliographical references.
- ItemOpen AccessMid-Term Outcome Of A Decade Of Delayed Total Cavopulmonary Connection Completion Strategy At Red Cross War Memorial Children's Hospital.(2023) Swai, Noel; Brooks, Andre; Zühlke LieslBackground: Total cavo-pulmonary connection (TCPC) is currently the definitive palliative operation for single ventricle congenital anomalies. It is the last stage in the single ventricle pathway and can be completed following a bidirectional Glenn shunt (BGS), if a set of strict criteria are met. The TCPC is inherently an ineffective circulation, and long-term complications are inevitable. In an attempt to delay TCPC circulation-related complications, we have followed a delayed TCPC completion strategy and maintenance of forward flow at the time of bidirectional Glenn shunt circulation whenever possible. In this study, we will describe the results over the last decade. Materials and Methods. Single-centre, retrospective study from January 1, 2009, to December 31, 2018. A total of 42 patients underwent extracardiac TCPC procedures on cardiopulmonary bypass. The most common indication for TCPC was Tricuspid atresia (56%). The median age at the time of operation was 9 [Interquartile range: 7 – 11] years. The median time interval between the bidirectional Glenn shunt and TCPC procedure was 6 [IQR: 4 - 9] years. The median followup was 24 [Interquartile range: 12 – 43] months. Results: Most common postoperative morbidities were prolonged pleural effusion 22 (58%) and infection 16 (38%) which were independently risk factors for prolonged hospital or intensive care unit (ICU) stay respectively. There was no 30-day mortality, and the 1-year and 5-year survival rates were 98% and 88%, respectively. The preservation of forward flow at the time of BGS did not prolong the time interval between the two procedures. Conclusion: Delayed TCPC strategy with or without retention of forward flow at the time of bidirectional Glenn circulation has shown acceptable outcomes. In this series, we did not show any benefit in the retention of forward flow. This strategy may be ideal in a resource-limited environment. We recommend the implementation of infection and pleural drainage control management protocols to avoid prolonged ICU and hospital stays.
- ItemOpen AccessOutcomes of "off-pump" coronary artery bypass grafting in a developing country : advantages over coronary artery bypass grafting on cardiopulmonary bypass(2010) Ofoegbu, Chimu K P; Brink, Johan GOff-pump coronary artery bypass grafting (OPCAB) was developed to avoid the deleterious effects of CPB. Current literature reveals some peri-operative advantages of OPCAB, with few studies detailing these in Africa. We review our institutional experience with both approaches in higher risk patients to determine pre-operative characteristics, short and mid-term outcomes in a developing country.
- ItemOpen AccessPathophysiological effects of brain death on potential donor organs, and the introduction of a new method of donor management(2007) Novitzky, DimitriIncludes abstract. Includes bibliographical references.
- ItemOpen AccessPenetrating injuries of the thoracic aorta and its branches(1996) Fulton, James Oliver; De Groot, K MPenetrating injuries of the intrathoracic great vessels are well recognized although uncommon. In the First World War no survivors with thoracic vascular injury were recorded among soldiers treated with penetrating injuries to the chest as recorded by Makins. The first record of successful repair of a penetrating thoracic aortic injury was in 1922 by Dshanelidze in Russia. Similar to Makins' experience, De Bakey and Simeone in the Second World War recorded no surviving patients with involvem_ent of the thoracic aorta and its branches among American soldiers. Furthermore, no injuries to the thoracic aorta and its branches were recorded in Korean war soldiers undergoing vascular surgery by both Jahnke and Hughes. Rich reported 3 survivors of aortic injuries in the Vietnam war among 1000 patients with vascular injuries. By 1969 only 43 successfully treated cases had been reported but increasing numbers of patients sustaining injuries to the great arteries at the level of the thoracic inlet have been reported subsequently in civilian practice. Experience has grown over the years but patient numbers remain small and individual surgeons may only manage 2 or 3 of these patients in his life time. The largest single reported series consists of 93 patients in Memphis over a 13 year period. All victims were rapidly transported to hospital and were resuscitated en route. As a consequence, a large number critically ill patients reached hospital who may have died in earlier years. However some of these patients inevitably died in hospital contributing to the high mortality of 16, 7% reported. Our experience is different in that most of our victims who reach hospital will survive as poor community triage facilities prevent more than 95% of penetrating thoracic vascular trauma victims reaching hospital alive, hence we have a selection of less severely injured patients who eventually reach our hospital alive producing our mortality rate of 5%. Another important difference is that most of our patients suffered stab wounds as compared to gunshot wounds noted in the Memphis. Buchan and Robbs in Durban reported on 52 patients who had penetrating cervicomediastinal vascular injury with a remarkably similar experience to our own in Cape Town with the exception of a larger number of aortic injuries (21 out of 52 patients) recorded and a higher mortality rate of 17% as a result of these aortic injuries.
- ItemOpen AccessThe performance of cross-linked acellular arterial scaffolds as vascular grafts; pre-clinical testing in direct and isolation loop circulatory models(2016) Pennel, Timothy; Bezuidenhout, Deon; Zilla, PeterThere 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.
- ItemOpen AccessPlasma and leukocyte gelatinases in health and disease(2004) Marillier, Reece Gerrad; Marais, Adrian; Davies, Neil
- ItemOpen AccessRelevance of the immune response in structural dysfunction of contemporary bioprosthetic heart valves : the role of cross-linking(2001) Human, Paul Andrias; Zilla, PeterIncludes bibliography.
- ItemOpen AccessRetrospective review of paediatric rheumatic mitral valve repairs and replacements done at Red Cross War Memorial Children's Hospital (RCWMCH) over a decade(2016) Mureko, Alfred; Brink, Johan G; Hewitson, JohnObjectives: Rheumatic heart disease remains a significant cause of morbidity and mortality and it is the leading cause of acquired paediatric cardiac disease in the developing world. The aim of this study was to understand the burden of rheumatic heart disease and to review the surgical management of rheumatic mitral valve disease at our institution. Methods: We retrospectively reviewed 76 consecutive patients who underwent mitral valve surgery for rheumatic heart disease between 1998 and 2010. The results and follow-up were reviewed, where death and reoperation were the primary endpoints. The follow up included a review of the latest information from the patients' medical records and telephonic interviews or home visits. Results: A 91% follow up was achieved over a median follow up period of 7.4 years (range 0.1-15.2 years). The mean age at surgery was 10.7 years (SD +- 2.7 years). The females constituted 66% and males 34%. Mitral valve repairs were performed in 64% of patients and of the 64% repairs, 0.06% only had commissurotomies. Replacements were performed in 36% of patients. All mitral valve replacements were mechanical prostheses. The actuarial freedom from reoperation for repairs was 83% (+-2.2) and 66% (+-3.4) at 5 and 10 years and for replacements was 87% (+-4.8) and 87%(+-4.8) respectively (p=0.27). Actuarial freedom from embolic cerebrovascular accidents in the repair group at both 5 and 10 years was 100%, compared to 90.2% (+-6.6) and 79% (+-12.0) for the replacement group at 5 and 10 years respectively (p=0.02). Actuarial freedom from death at 5 and 10 years for children over 12.8 years was 77.7% (+-9.9) and 69.1% (+-12.0) respectively, compared to 93.6% (+-3.6) and 93.6% (+-3.6) for children under 12.8 years (p=0.03). No statistical significant difference was noted in freedom from valve related failure and death between repairs and replacements. Conclusions: There was no significant difference in survival between mitral valve repairs and replacements. There was surprisingly worse survival among children who were above 12.8 years at time of the surgery.
- ItemOpen AccessSixteen year retrospective analysis of rheumatic and non-rheumatic heart disease patients undergoing valve procedures at Groote Schuur Hospital first incidence single aortic and mitral valve replacement(2012) Ogunrombi, Akinwumi Babatunde; Human, PaulRheumatic heart disease is still the most common cause of valvular heart lesions requiring replacement or repair procedures worldwide. In South Africa, where there is an interesting mix of first and third world dynamics, factors sustaining the epidemic of rheumatic disease are still commonplace. The choice of appropriate valve procedure and prosthesis in our setting will depend on an adequate knowledge of short and long term outcomes of valve replacement and repair. The aim of this thesis was to evaluate the demographics and presentation of our rheumatic and non-rheumatic patients and to determine if our current implantation choices could be validated.
- ItemOpen AccessSurgical management for atrial fibrillation an assessment of clinical after irrigated monopolar electrocautery ablation(2009) Scherman, Dr Jacques; Brink, Johan G
- ItemOpen AccessTen-year propensity matched cohort analysis of mitral valve repair and replacement for rheumatic heart disease at Groote Schuur Hospital(2011) Geldenhuys, Agneta; Zilla, PeterIncludes abstract. Includes bibliographical references.
- ItemOpen AccessUltrasonography Evaluation of Patency of Implanted Infra-Renal Vascular Grafts in the Rat Model.(2020) Da Silva, Natercia; Pennel, Timothy; Bezuidenhout, Deon; Hadebe, Nkanyiso; Zilla, PeterIntroduction: 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.