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Biomedical subjects

H Laks

Publications and source records attributed to H Laks.

339 records · Page 19Linked to original sources
PubMedDate not supplied

Clinical experience with centrifugal pump ventricular support at UCLA Medical Center.

The experience using the vortex centrifugal pump as a ventricular assist device at The University of California, Los Angeles and Wadsworth V.A. Medical Centers is reviewed. Thirteen adult and one pediatric patients were supported postcardiotomy, 10 LVAD, 3 BIVAD, and 1 RVAD. There were no equipment failures over a mean perfusion time of 52 hr (range 12-140 hr). Seven of thirteen adult patients were supported and weaned from 6 LVAD and 1 BIVAD. Three patients underwent orthotopic heart transplantation, and the other four recovered ventricular function, of whom five are longterm survivors at a mean followup time of 16 months. In one patient bridged to transplantation, a prior infection caused the patient to succumb after successful transplantation. All patients assisted for transplantation are carefully screened, and would be excluded from transplantation if they developed significant infection, or irreversible renal or neurologic limitations.

Aged↗
PubMedDate not supplied

The heterotopic right heart assist transplantation.

Heterotopic heart transplantation has been utilized experimentally and clinically to assist the recipient heart in maintaining either the systemic circulation alone or both the systemic and pulmonary circulations. We describe a model in which the heterotopic heart transplantation is utilized to supply the pulmonary circulation while the recipient heart acts as the systemic ventricle. This procedure might be used for selected patients with complex congenital heart disease. The method we have used in five dogs (16.5 to 23.5 kg) consists of preparation of the donor heart by excision after cardioplegic arrest, ligation of the venae cavae, anastomosis of the donor pulmonary artery (PA) to the donor left atrial appendage, and insertion of a left ventricular (LV) apical Dacron graft connected to a valved aortic allograft. Implantation in the recipient consists of anastomosis of the donor left atrium to the recipient right atrium, anastomosis of the LV apical conduit to the recipient main PA, and anastomosis of the donor aorta to the recipient ascending aorta to supply oxygenated blood to the donor coronary circulation. The recipient right ventricle (RV) in the experimental model is inactivated by inducing tricuspid regurgitation and by ligating the proximal PA. Early survival (3 hours) with stable hemodynamic measurements was obtained in all dogs, with the recipient RV excluded from the circulation and with the donor LV pumping the total systemic venous return to the PA. Pulmonary blood flow was maintained even when the ventricular pressure was raised to systemic levels by narrowing the conduit.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Heart transplantation in a Jehovah's Witness.

Heart transplantation has been successfully performed without blood products in a 45-year-old Jehovah's Witness. Management of this patient is described. The medical, ethical, and religious issues involved in the decision to offer transplantation and to accept it are discussed.

Blood Transfusion, Autologous↗
PubMedDate not supplied

Urgent priority transplantation: when should it be done?

The success of heart transplantation has created longer waiting lists of candidates, some of whom require transplantation urgently. Decisions must be made regarding which patients require urgent transplantation and how many donor hearts should be committed to urgent transplantation. To determine whether some patients who are considered refractory to medical therapy may be stabilized for elective transplantation, 40 patients transferred for urgent transplantation underwent intensive vasodilator and diuretic therapy, and outcomes were determined. To examine the impact of urgent transplantation on survival, we then determined the survival for urgent priority candidates in the western region. Discharge of the patients who were receiving oral dosages of vasodilators and diuretics was possible for 32 of 40 patients (80%), with a 6-month actuarial survival of 75% on medical therapy, despite an initial ejection fraction of 0.15 +/- 0.04, a cardiac index of 1.9 +/- 0.6 L/min/m2, and a pulmonary wedge pressure of 30 +/- 8 mm Hg. Of 11 patients discharged to await regular priority transplantation, one died suddenly, one died postoperatively, and the others went home 14 +/- 4 days after transplantation. The eight patients unable to be discharged after transfer had lower initial mean arterial pressures and serum sodium levels. Of 59 urgent priority patients from the five western region programs, 50 patients underwent transplantation after 33 +/- 41 days. Subsequent 1-month survival was 88% and overall survival 80%, compared with 97% and 90% in 137 regular priority patients, with a 4.5 times greater risk of early mortality in the urgent group (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Emergencies↗
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Polypeptide composition and histopathologic changes in endomyocardial biopsies from transplanted human hearts.

Sequential postoperative samples of 43 human right ventricular endomyocardial biopsies from four heart transplant patients were evaluated histopathologically to assess microscopic parameters of rejection. Selected pieces of these myocardial biopsies were weighed and homogenized in low ionic strength buffer containing Triton X-100 to extract and to quantitate cardiac actin. Aliquots of the soluble fractions were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Residual pellets were solubilized and also underwent SDS-PAGE. Electrophoretograms were analyzed densitometrically. Actin from biopsies from transplanted human hearts accounted for approximately 40% of Triton X-100 soluble polypeptides. Actin and myosin heavy chain content in the pellet fractions was unchanged as a function of allograft duration. A polypeptide band resolved between 14,000 and 21,000 daltons in the Triton-soluble fraction of four fresh samples correlated with histopathologic changes of moderate acute allograft rejection. A similar band was noted in 11 frozen endomyocardial biopsy specimens without changes of acute rejection. Small actin differences may be found in the transplanted heart, but they do not correlate with rejection. The presence on SDS-PAGE of the polypeptide band found between 14,000 and 21,000 daltons may correlate with proteolysis of cytoplasmic proteins either from rejection or possibly from autolysis after freezing.

Actinin↗
PubMedDate not supplied

A new operation for aortic stenosis in the young: total left ventricular output through an apical-abdominal aortic shunt. A seven year follow-up.

Left ventricular outflow disease causes particular problems in the small child. Although aortic stenosis may be palliated by commissurotomy, valve replacement, if that appears necessary, is essentially not a practical procedure due to the small valve necessary to occupy the sub-coronary position. The combined lesion of aortic stenosis and regurgitation in childhood is an especially difficult lesion because any attempt to relieve the stenosis is extremely likely to increase the regurgitation. Sometime ago, we had the opportunity to manage a 22-month old youngster with severe congestive failure due to aortic stenosis with regurgitation. Because of the small size of the aortic root, it was elected to close the aortic valve and perform an apical abdominal aortic valve-containing shunt such that the entire left ventricular outflow was delivered to the abdominal aorta. The child has now been followed over seven years and is the subject of this report.

Aorta, Abdominal↗
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Expression of major histocompatibility antigens and vascular adhesion molecules on human cardiac allografts preserved in University of Wisconsin solution.

The impact of cold storage of cardiac allografts on expression of major histocompatibility complex antigens and vascular adhesion molecules is not known. We obtained serial endomyocardial biopsy specimens at harvest, on implantation, and approximately 15 minutes after reperfusion from six consecutive human cardiac allografts stored in University of Wisconsin solution. Cold ischemia time was 187 +/- 45 minutes. A fourth endomyocardial biopsy specimen was obtained from the recipients of cardiac allografts 1 week after operation. Expression of major histocompatibility complex antigens and vascular adhesion molecules was studied by immunohistochemistry. The intensity was scored blindly by a semiquantitative method. On vascular endothelial cells, the expression of major histocompatibility complex class I and II antigens was strong; ICAM-1 expression was moderate, and expression of VCAM-1 and ELAM-1 was weak to absent. The expression of these antigens on vascular endothelial cells did not change in sequential biopsy specimens. The expression of major histocompatibility complex class I antigens on myocardial cells was weak and remained unchanged. Myocardial cells did not express major histocompatibility complex class II antigens, ICAM-1, VCAM-1, or ELAM-1 on serial examinations. During cold storage of cardiac allografts in University of Wisconsin solution, the expression of major histocompatibility complex antigens and vascular adhesion molecules on endothelial cells and myocardial cells remains unchanged.

Adenosine↗
PubMedDate not supplied

Experimental cardiac allograft vasculopathy in mice.

Cardiac allograft vasculopathy is the most common cause of death in heart transplant recipients after the first postoperative year. The pathogenesis of cardiac allograft vasculopathy is not clearly defined. To better study this disease, a genetically well-defined and reproducible animal model such as the mouse is needed. We performed heterotopic, intraabdominal heart transplantation between two inbred strains of mice. The B10.A strain served as donors, and the B10.BR strain served as recipients. No immunosuppressive therapy was administered. The allografts in groups I (n = 6) and II (n = 6) were harvested at 30 and 50 days after operation, respectively. All allografts had palpable contractions at the time of harvest. The cardiac allografts from both groups showed mild to moderate acute cellular rejection. In groups I and II, 55% +/- 26% and 60% +/- 18% of arteries showed intimal thickening, respectively. Pathologically, the vascular lesions were characterized with varying degrees of intimal thickening, subendothelial mononuclear cell infiltration and fibrosis, frequent disruption of the internal elastic lamina, and perivascular inflammation. These findings are characteristic of cardiac allograft vasculopathy seen clinically. Isografts (n = 6) showed no vascular lesions. The heterotopic transplantation of B10.A-strain hearts into B10.BR recipients provides a useful murine model for future studies in the pathogenesis and treatment of cardiac allograft vasculopathy.

Animals↗
PubMedDate not supplied

Orthotopic heart transplantation and concurrent coronary bypass.

Lack of donor organ availability is an increasing problem in heart transplantation. Methods to safely increase the donor pool are desperately needed. We report four cases of coronary artery bypass during orthotopic heart transplantation for donor hearts with normal ventricular function and subclinical coronary artery disease. An aggressive approach toward utilizing hearts from older donors with normal ventricular function may expand the donor pool and decrease the waiting period, with its attendant death, for patients awaiting heart transplantation.

Aged↗
PubMedDate not supplied

Does short-course induction with OKT3 improve outcome after heart transplantation? A randomized trial.

OKT3 is often used routinely for induction immunotherapy or selectively to avoid acute cyclosporine nephrotoxicity in heart transplant recipients at high risk for immediate postoperative kidney failure. It has not been shown in a randomized trial to be useful in patients at low risk for early kidney failure. We randomized 30 patients with a serum creatinine level of less than 1.4 mg/dl before heart transplantation to be treated with triple-drug immunotherapy with cyclosporine, which was started before surgery, (group 1) or to be treated with OKT3 for 4 to 6 days after surgery with oral cyclosporine, which was started between days 2 and 4, after renal function had stabilized (group 2). Follow-up for 6 months revealed no significant differences in the total number of rejection episodes, total number of infections, or in the serum creatinine level. Four patients in group 1 and five patients in group 2 have had no rejection. OKT3 showed a trend to delay time to first rejection (p = 0.10), as has been reported for the 14-day induction course of OKT3. A short course of OKT3 induction in heart transplant recipients at low risk for immediate postoperative kidney failure prolongs the time to first rejection for most patients but does not appear to reduce the total incidence of rejection in the first 6 months after heart transplantation.

Creatinine↗
PubMedDate not supplied

University of Wisconsin solution versus Stanford cardioplegic solution and the development of cardiac allograft vasculopathy.

BACKGROUND: University of Wisconsin (intracellular) solution has been shown to offer some distinct benefits of myocardial preservation over Stanford (extracellular) solution, including a more rapid functional recovery, improved adenosine triphosphate preservation, and a tendency for less postoperative inotropic agents. However intracellular solutions with high potassium content have been reported to cause a functional if not structural endothelial injury in laboratory experiments. METHODS: Because of this information we retrospectively viewed our follow-up angiographic data for the development of the cardiac allograft vasculopathy in a consecutive series of 195 heart transplant recipients. These patients were treated in identical fashion, with the same immunosuppression regimen, except for the type of cardioplegia used--Stanford solution (group I n = 95) and University of Wisconsin solution (group II n = 100). RESULTS: With a mean follow-up of 24 months after transplantation, a significant difference was seen in the development of cardiac allograft vasculopathy in group II (22%) versus group I (14%, p < 0.03). Although significant differences were observed with univariate analysis with respect to donor age and ischemic time favoring group I and with multivariate statistical analysis with respect to overall rejections favoring group II, the only significant variable for the difference in the development of allograft vasculopathy was University of Wisconsin cardioplegic solution (p < 0.003). A subgroup of 30 patients previously randomized for a functional study comparing the two cardioplegic agents showed a tendency for statistical significance with a freedom from allograft vasculopathy of 93% in group I, as compared with 83% in group II, after 13 months follow-up (p = 0.09). The overall probability of being free of vasculopathy at 24 months was 86% for group I and 70% for group II. CONCLUSIONS: The data support the conclusion that University of Wisconsin intracellular solution is associated with an increased incidence of vasculopathy versus Stanford solution and warrants investigation for modification of this preservation agent in heart transplantation.

Adenosine↗
PubMedDate not supplied

Corticosteroid weaning late after heart transplantation: relation to HLA-DR mismatching and long-term metabolic benefits.

BACKGROUND: To avoid the long-term side effects of corticosteroids, corticosteroid-free immunosuppression has been introduced immediately or late (more than 6 months) after heart transplantation. Late corticosteroid weaning may have a higher success rate as patients are selected on the basis of rejection history. Previous reports of HLA-DR mismatching and the long-term metabolic benefits with respect to corticosteroid weaning have been equivocal. METHODS: One hundred and one eligible heart transplant recipients receiving triple-drug immunosuppression 6 months from heart transplantation were weaned from prednisone by decreasing the daily prednisone dose by 1 mg each month. Moderate rejection episodes were recorded and after conclusion of the study, HLA-DR mismatching of recipient and donor was reviewed. Serum cholesterol level, body weight, and number of patients receiving blood pressure medications were recorded before and 1 year after corticosteroid weaning. RESULTS: Successful weaning from corticosteroids was achieved in 82% of patients. Of 31 patients with zero or one HLA-DR mismatch, 30 (97%) were successfully weaned. For those patients more than 1 year after discontinuation of corticosteroids, 67 had more weight loss and a lower serum cholesterol level than 15 patients who were unsuccessful at corticosteroid weaning and dependent on corticosteroids. CONCLUSIONS: Heart transplant recipients can safely be weaned from corticosteroids late after heart transplantation with zero or one HLA-DR mismatch conferring a higher success rate. The long-term metabolic benefits of corticosteroid weaning include a reduction in weight and serum cholesterol.

Body Weight↗