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Biomedical subjects

D K Cooper

Publications and source records attributed to D K Cooper.

At least 253 records · Page 14Linked to original sources
PubMed1984

Cyclosporin A in the management of patients with heart transplants. Initial experience at Groote Schuur Hospital.

During the year February 1983 - February 1984 10 patients received immunosuppressive therapy with cyclosporin A (CYA) and methylprednisolone (MP) after either heterotopic or orthotopic heart transplantation. Two of these patients were undergoing severe acute rejection episodes (intractable to conventional immunosuppressive therapy) when CYA administration was initiated; both episodes were reversed and neither patient suffered further rejection. The remaining 8 patients received CYA from the time of transplantation. Two patients died 7 and 9 days postoperatively from multi-organ failure; in retrospect, excessively high dosages of CYA were administered, resulting in very high blood levels of the drug, which may have contributed to renal failure. One patient died (while living abroad) of a possible septicaemia 8 months after transplantation, having otherwise done well. Seven patients remain alive and active 3 1/2 - 15 months after operation. The incidence of both severe acute rejection episodes and life-threatening infection would appear to be lower in patients receiving CYA and MP when compared with earlier patients at our institution who received conventional immunosuppression. Frequent monitoring of whole-blood levels of CYA is necessary to ensure that the nephrotoxic effect of the drug is minimized.

Adult↗
PubMed1984

Valve replacement in patients over 70 years of age.

Between 1 August 1975 and 31 October 1982, 76 patients aged between 70 and 82 years (mean 73,4 years) underwent elective (71) or emergency (5) valve replacements. Fifty patients underwent aortic valve replacement (including 5 with additional coronary artery bypass grafts), 19 mitral valve replacement including 3 with coronary artery bypass grafts, and 7 double valve replacements. There were 3 early deaths (3,9%) and 9 late deaths (11,8%) during the follow-up periods of 1 month - 86 months (mean 29 months). Actuarial analysis showed a survival rate of 95% at 1 year, 89% at 2 years, and 77% at 5 years. The clinical result of operation was judged to be good or excellent in all patients except one. It is concluded that valve replacement in patients over 70 years carries a low operative risk, statistically similar to that for younger patients at our institution, and is accompanied by a satisfactory result.

Age Factors↗
PubMed1984

Prediction of acute cardiac rejection using radionuclide techniques.

Radionuclide scanning of the donor left ventricle using technetium-99m-labelled red cells was used to monitor acute rejection after heterotopic heart transplantation and compared with histopathological evidence of rejection obtained at examination of an endomyocardial biopsy specimen. The ejection fraction and end-diastolic, end-systolic and stroke volumes were calculated at each examination; an equation was derived from these data to predict the degree of acute rejection, using histopathological examination of endomyocardial biopsy specimens as criteria of the presence and severity of rejection. A highly significant multiple correlation between radionuclide scanning parameters and endomyocardial biopsy was found. The advantages of non-invasive radionuclide scanning over the invasive procedure of endomyocardial biopsy are discussed.

Adolescent↗
PubMed1984

Comparison of patients with ischemic, myopathic, and rheumatic heart diseases as cardiac transplant recipients.

Fifty-four human-to-human cardiac transplants (10 orthotopic and 44 heterotopic) in 50 patients were performed between December, 1967, and December, 1981. The underlying cardiac pathology was ischemic (IHD) in 29, cardiomyopathic (CM) in 17, rheumatic (RHD) in four, and mixed or other pathology in four. Patients with RHD survived for a mean period over three times as long as those with either CM (p less than 0.02) or IHD (p less than 0.05). Although CM patients were on average over a decade younger than those in other groups, they had a lower survival rate. There was a higher incidence of death from chronic rejection in patients with IHD, in whom there was also a higher incidence of thromboembolic episodes. Major infections were over twice as frequent in IHD patients as in CM patients (p less than 0.01). Noncompliance with regard to adherence to instructions and therapy was a significant factor in morbidity and mortality, especially in CM patients. Our data suggest that survival and morbidity of recipients of heart transplants might be influenced to some extent by the nature of the underlying primary cardiac condition, RHD being considered a favorable survival factor when compared with IHD, and CM being particularly unfavorable.

Adult↗
PubMed1984

Lack of efficacy of high-dose verapamil in preventing brain damage in baboons and pigs after prolonged partial cerebral ischemia.

There has been mounting speculation that calcium antagonists may be useful in reducing or preventing brain damage after cardiopulmonary resuscitation. To test the clinical usefulness of these agents in averting such damage, high-dose verapamil was administered to baboons and pigs after partial cerebral ischemia for varying periods of time. In Group A baboons and pigs, the major aortic branches supplying the carotid and vertebral circulations were clamped for periods ranging from 15 to 150 minutes, and neurological recovery was observed. In Group B, verapamil hydrochloride 0.7 mg/kg was given by intravenous infusion after similar periods of arterial occlusion. The administration of verapamil did not lead to any clinically improved neurological outcome. The use of verapamil after prolonged periods of partial cerebral ischemia did not improve neurological recovery in baboons and pigs.

Animals↗
PubMed1984

Cardiac transplantation following storage of the donor heart by a portable hypothermic perfusion system.

Four patients have undergone heterotopic heart transplantation with donor hearts stored by a portable hypothermic perfusion system. Total ischemic periods ranged from 6 hours 55 minutes to 16 hours 50 minutes. One heart, transplanted into a patient who had acutely rejected a previous graft, suffered accelerated, irreversible, acute rejection within five days, associated with strong antibody formation; donor heart function was never good. In the 3 remaining patients, donor heart function was good after initially being poor for a few hours in 2 patients. One patient died of long-term rejection after 6 months and 1 of tuberculous meningitis after 10 months; 1 remains alive at 15 months. Neither preservation of the donor heart for periods in excess of approximately 4 hours nor the use of continuous hypothermic perfusion as a method of preservation appears to have been reported previously in the context of the clinical situation.

Adult↗
PubMed1984

Orthotopic and heterotopic transplantation of the heart: the Cape Town experience.

The world's first human-to-human heart transplant was performed at Groote Schuur Hospital on the 2nd December 1967. Between 1967 and 1973, 10 patients underwent orthotopic heart transplantation. Four lived for more than 1 year. The longest survivor died after 12 1/2 years, and one patient remains alive and fully employed 11 1/2 years after transplantation. Since 1974, 44 patients have undergone heterotopic heart transplantation, whereby the donor heart is inserted in parallel with the recipient's own heart. Four of these patients have undergone retransplantation for acute or chronic rejection. Survival has been almost 60% for 1 year, falling to 21% by 5 years. The major complications of heart transplantation have been early acute and late chronic rejection; immunosuppression has been complicated by a high incidence of infection, particularly during the first year, and by a 10% incidence of the development of malignant tumors. A portable hypothermic perfusion system has been developed to store and transport donor hearts for periods of up to 24 hours.

Adolescent↗
PubMed1983

Malignant neoplasms occurring after cardiac transplantation.

Fifty-seven cardiac transplants in 53 patients have been performed; 30 survived for at least three months. Malignant neoplasms developed in three (10%) of these patients. This incidence is more than double that in recipients of donor kidneys at our institution. Kaposi's sarcoma developed in three patients in the combined groups and accounted for 30% of all malignant neoplasms. The possible reasons for these high incidences are discussed.

Adenocarcinoma↗
PubMed1983

Trends in cardiac surgery at the University of Cape Town, 1971-1981.

A review has been undertaken of the number and types of surgical procedures performed in the Department of Cardiac Surgery of the University of Cape Town during the 11-year period 1971-1981, together with data on associated mortality. A yearly average of 560 operations was carried out, of which 75% were for acquired and 25% for congenital heart disease. The number of patients treated continues to rise, from 434 in 1971 to 690 in 1981. There has been a slight reduction in the overall average yearly mortality, from 6.1% between 1971 and 1975 to 5.0% between 1976 and 1981. There was a significant increase in the number of valve replacements in 1975 and 1976 and a more recent, continuing increase in operations for ischaemic heart disease, which now form 19% of the total operations. In both these groups the average yearly mortality has fallen during the period of study. The number of operations each year for congenital heart disease has remained fairly constant, but, disappointingly, there has been no significant reduction in mortality.

Adolescent↗
PubMed1983

Orthotopic allotransplantation and autotransplantation of the baboon heart following 24-hr storage by a portable hypothermic perfusion system.

A nonpulsatile perfusion apparatus, based on the air-lift pump principle, has been developed. Circulation of the perfusate, as well as oxygenation and maintenance of acid-base balance, is provided by the flow of a mixture of 97% oxygen and 3% carbon dioxide. The system is easily and entirely portable. Eleven baboons underwent orthotopic allotransplantation with donor hearts stored by continuous hypothermic (4-10 degrees C) perfusion for periods of up to 24 hr. Three were electively killed after 2 to 3 days; the remaining eight, immunosuppressed with methylprednisolone and either azathioprine or cyclosporin A, survived to rejection at between 10 and 49 days. Cardiac catheterization performed in six animals 7-14 days after allotransplantation showed virtually normal hemodynamic data. Three more baboons underwent heart excision and storage by hypothermic perfusion for 24 hr, and subsequent othotopic autotransplantation, the circulation of the baboon being maintained in the interim by an allograft. One animal survives 8 months later with hemodynamic data at cardiac catheterization differing little from that obtained before autotransplantation. This perfusion system has subsequently been used to store four human donor hearts prior to heterotopic transplantation.

Animals↗
PubMed1983

The surgical technique of heterotopic heart transplantation.

The surgical technique of heterotopic heart transplantation is detailed and illustrated. The donor heart is excised after cardioplegic arrest and topical cooling; its preparation and implantation in the recipient are described. Emphasis is placed on ensuring nonrestrictive anastomoses between the left and right atria of the recipient and the donor, on estimating the optimal length of the donor aorta, and on the insertion of a prosthetic graft between the donor and the recipient pulmonary arteries. Forty-six such transplants have been performed to date without operative or early postoperative mortality related to technical problems.

Heart Atria↗
PubMed1983

Cryptic mediastinal masses causing airways obstruction.

In 3 infants, severe airways obstruction was caused by mediastinal lesions which were not evident on the antero-posterior chest radiograph. Their presence was demonstrated by barium swallow examination. Each infant had thoracotomy carried out urgently. Duplication cysts (without associated cervicodorsal vertebral anomalies) were present in 2 patients and neuroblastoma in the third.

Airway Obstruction↗