Biomedical subjects
Publications and source records attributed to B A Reichart.
A 5-month-old infant with congenital mitral valve disease successfully managed by replacement with a mechanical prosthetic valve is reported. The incidence and management of congenital mitral valve defects is discussed.
The acute surgical management of a 22-year-old male patient with a stab wound below the left sternoclavicular junction causing partial transsection of the origin of the innominate artery, laceration of the posterior wall of the ascending aorta, as well as an innominate artery-vein fistula, is described and the value of inflow occlusion in the surgical repair discussed.
Malignant fibrous histiocytoma is a recently recognised common sarcoma of late adult life which, rarely, may arise in the heart. Unlike the atrial myxoma, which it may mimic clinically, malignant fibrous histiocytoma is a far more aggressive tumour with a greater tendency for local recurrence and infiltration. A case of a primary intracardiac malignant fibrous histiocytoma is reported and relevant published reports reviewed.
Human allogeneic heart transplantation was started at Groote Schuur Hospital in Cape Town in 1967. Since then 110 hearts (61 heterotopic and 49 orthotopic) and 12 heart-lung transplantations have been performed in the unit. Ten procedures were retransplantations including 2 third interventions. The patients fall into three groups according to their immunosuppressive therapy: group A (N = 55) from 1967 to 1982 received the so-called 'conventional treatment' (azathioprine, methylprednisolone and antithymocyte globulin (ATG)); group B (N = 15) from 1983 to 1984 received cyclosporin A in high dosage, together with methylprednisolone; and group C (N = 30) received quadruple drug therapy of low-dose cyclosporin A, together with azathioprine, methylprednisolone in lower dosages and antithymocyte globulin (for the first 4-6 days and rescue-ATG for severe rejection). The results have improved significantly over the years. The actuarial survival rate after heart transplantation within the last 12 months is 94%. Several important steps have been inaugurated: in 1973 heterotopic heart transplantation was initiated and in 1984 hormonal therapy of brain-dead organ donors was started. Radionuclide scanning, in combination with endomyocardial biopsies, has proved to be a very sensitive means of monitoring rejection.
The performance of the St. Jude prosthetic valve is reviewed in 81 patients aged 3 to 15 years. All 66 mitral (2 re-replacements), 8 aortic and 9 double valve replacements between February 1979 and August 1984 are included. The early mortality was 3.7% and actuarial analysis shows a 90% event free survival up to 5 years. Anticoagulant therapy was used in most patients, but comparison between groups receiving warfarin or aspirin or no therapy reveals no differences in the complication rate. The valve is well suited for use in children since the early degeneration seen with heterograft valves does not occur, and anticoagulation is not essential.
The results of 53 femoral to tibial artery bypass grafts have been reviewed. All were carried out in an attempt to salvage severely ischemic extremities which resulted from arteriosclerotic occlusive disease involving the femoral, popliteal, and tibial arterial systems as demonstrated by arteriography. Most grafts were done with autogenous vein; however, composite grafts comprised of a Dacron prosthesis and an autogenous vein and homologous veins were used in several patients. The initial salvage rate in these pregangrenous extremities was 74%. Fifty-two percent of the grafts remain patent at this writing, a period of 56 months in some instances. This study indicates that most patients with a severely ischemic extremity are candidates for revascularization and should have angiographic studies before amputation is considered.
Twelve Chacma baboons underwent transplantation of the heart and both lungs from donor baboons matched for size and AB blood group. Cyclosporine was given daily orally, by twice daily intravenous injections, or by a single intravenous injection (together with oral azathioprine and, after 2 weeks, methylprednisolone); whole blood trough levels were inadequate in all groups. Survival was from 4 to 29 days, with death resulting from acute rejection of the lungs in 11 and from bronchopneumonia in one. In the 11 animals dying from rejection, histologic examination showed that the heart was spared from severe rejection in all cases but one. In the inadequately immunosuppressed baboon, therefore, acute rejection occurs earlier in the lungs than in the heart. We have now observed what we believe to have been acute pulmonary rejection in the absence of cardiac rejection on five occasions in three patients in our clinical transplantation program. We would suggest that pulmonary rejection must always be strongly suspected if there are any suggestive features, particularly pulmonary shadowing on chest radiographs, despite negative results of tests indicating rejection of the heart. In the absence of any easy method of confirming pulmonary rejection directly (other than open-lung biopsy, which is clearly contraindicated as a routine procedure), we suggest that more attention should be directed toward developing tests for rejection that are not organ specific, rather than relying on techniques that diagnose cardiac rejection only.
En bloc transplantation of the heart and lungs was performed in 15 chacma baboons; the donor organs were stored between 4 and 6 hours before transplantation. The hearts were perfused in the donor animals with 15 ml/kg Wicomb's cardioplegic solution at 4 degrees C, the lungs with either 20 ml/kg 4 degrees C Collins' solution with an added 2.5% dextrose and 12 mEq magnesium sulfate (Collins' solution, group 1, n = 8), Collins' solution plus superoxide dismutase (40,000 U/L superoxide dismutase, group 2, n = 4), or Collins' solution plus superoxide dismutase plus peroxidase (5000 U/L peroxidase plus mannitol, group 3, n = 3). The pulmonary artery perfusion pressure was not allowed to exceed 50 cm water; the lungs were maintained at 30% to 50% inflation, and external cooling was applied. After explantation the thoracic organs were stored in 0.9% saline solution at 4 degrees C. In groups 1 (Collins' solution) and 2 (Collins' plus superoxide dismutase) all surviving baboons revealed normal blood gas values and normal light and electron microscopic histology at 24 hours. Three animals had further biopsies at intervals between 1 and 9 days, at which time the histology of the lungs proved normal and well preserved. All three baboons in group 3 (Collins' plus superoxide dismutase plus peroxidase) had grossly abnormal blood gas values from the time of operation, and all died within 9 hours; light microscopy of the lungs showed early lung infarctlike lesions and in one case pulmonary edema. These preclinical findings proved that storage of the lungs in Collins' solution with or without superoxide dismutase is possible for up to 5 hours; the addition of peroxidase had a detrimental effect.
A reimplantation or reperfusion response has been described in both the experimental animal and the human patient after various procedures involving pulmonary ischemia. We have investigated this phenomenon in a primate model. Ten chacma baboons were placed on cardiopulmonary bypass and cooled to 20 degrees C. Circumferential segments of the right main bronchus and pulmonary artery were denuded of all surrounding tissue. Each structure was then cross-clamped, which rendered the lung ischemic, during which time the organ was immersed in cold saline solution. Ischemia was maintained for 1.5 to 5 hours; after reperfusion and discontinuation of bypass, the right lung was biopsied and the chest closed. Chest radiographs, lung biopsies, and arterial blood gases were taken at intervals for up to 16 to 28 days. Right lung shadowing on chest radiography with concomitant histopathologic changes, indicative of a reperfusion reaction, were seen in only one animal, which had undergone lung ischemia for 1.5 hours. In one other animal that was ischemic for 5 hours, patchy opacification of the lung was seen on two occasions (days 8 and 15) with concomitant mild histopathologic changes. In conclusion, therefore, a major reperfusion response after pulmonary ischemia in the chacma baboon is possible but unusual. This would suggest that the appearance of pulmonary opacification on chest radiography within the first 4 weeks after heart-lung transplantation in humans is most likely attributable to some other condition, such as isolated lung rejection or infection.