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Biomedical subjects

B A Reitz

Publications and source records attributed to B A Reitz.

At least 163 records · Page 9Linked to original sources
PubMed1985

The effect of hypothermic preservation of the heart and lungs on cardiorespiratory function following canine heart-lung transplantation.

The effect of hypothermic preservation of the heart and lungs with a crystalloid solution was evaluated in 12 mongrel dogs receiving heart-lung allografts. Six animals served as controls and received an immediate heart-lung transplant. Six animals were in the experimental group and received a heart-lung transplant after 5 hours of preservation at 4 degrees C following perfusion of both organs with a crystalloid solution. Physiological function of the heart and lungs was studied for 20 hours after transplantation. While cardiac function was minimally depressed following preservation, pulmonary function testing demonstrated significantly greater increases in extravascular lung water in experimental animals, suggesting that an ischemic lung injury occurred with this preservation technique. The model allows for future evaluation of other methods of combined preservation of both the heart and lungs for transplantation.

Airway Resistance↗
PubMed1985

Supradiaphragmatic renal cell carcinoma tumor thrombus: indications for vena caval reconstruction with pericardium.

Supradiaphragmatic extension of tumor thrombus from a renal cell carcinoma presents a major surgical challenge. The use of cardiopulmonary bypass, hypothermia and cardiac arrest with temporary exsanguination has allowed for successful surgical excision of these tumors. A renal cell carcinoma on the right side with a supradiaphragmatic tumor thrombus still may only partially occlude the vena cava. The collateral venous circulation of the left renal vein may be developed poorly and a pericardial patch can allow successful reconstruction of the inferior vena cava. If the tumor arises on the left side continued venous drainage of the right kidney is mandatory to prevent venous infarction of the right kidney. The entire vena cava also might be reconstructed theoretically with pericardium.

Blood Vessel Prosthesis↗
PubMed1985

Coronary artery bypass grafting in women. A ten-year perspective.

Between January 1974 and December 1983, 3279 patients have undergone isolated coronary artery bypass (CAB) grafting at the Johns Hopkins Hospital. There were 639 women in this group. Women represented 18 to 22% of the patients having isolated CAB grafting throughout the 10-year period, except in 1976 when only 13% of the CAB patients were women. Mean age-at-operation for women has increased from 53.9 to 61.1 years since 1974, and was higher than the mean operative age of men during each of the 10 years. Although the oldest woman undergoing CAB grafting in 1974 was 64 years old, the eldest in 1983 was 84 years old. Except for an older mean age-at-operation for women and a higher incidence of unstable angina prior to surgery, the only other significant difference in the clinical status of female versus male CAB patients, detected by a case control analysis, was the smaller body surface area of women compared to men. Although operative mortality was significantly greater for women during most of this review period, mortality was similar during 1983 (2.6% for men versus 2.4% for women), in spite of a significantly higher incidence of unstable angina in the female group (54% for women versus 35% for men). The improved survival noted following coronary bypass grafting in women, which occurred in spite of the advancing age of the female group, supports an aggressive approach to surgical intervention in women with severe coronary artery disease.

Age Factors↗
PubMed1985

Long-term cardiac and pulmonary histology in primates following combined heart and lung transplantation.

To investigate the long-term histologic consequences of combined heart and lung transplantation, heart and lung biopsies were obtained from six rhesus monkeys; two had undergone heart-lung autotransplantation 3.5 and 4.5 years previously, two were the recipients of heart-lung allografts 4.1 and 4.5 years previously, and the results were compared with two normal control animals. Cyclosporine had been used as maintenance immunosuppression in the allograft group. The heart and lung biopsies in the autograft animals were essentially normal. Dense adhesions were noted in the allografts, adn in one the visceral pleura was grossly thickened. Cardiac biopsies in the allografts were unimpressive, with a normal myocardium in one, and minimal interstitial fibrosis in the other. Intimal hyperplasia was present in the pulmonary arterioles of one of the allografted animals. Focal scarring was present in the lung of one allograft recipient, and the other animal showed severe thickening and fibrosis of the alveolar septae, as well as marked interstitial fibrosis such that large areas of the specimen were replaced by connective tissue. Histologic abnormalities in the allografted lungs correlated with the abnormal hemodynamics in these animals reported in a previous study. It is suggested that the histologic appearances in the lung are a consequence of chronic rejection, and that these findings may become a significant problem in human heart-lung transplant recipients.

Animals↗
PubMed1985

Twenty-four hour lung preservation by hypothermia and leukocyte depletion.

In lung preservation, as well as in other forms of pulmonary disease, injury is associated with sequestration of leukocytes. We hypothesized that leukocyte depletion could prevent reperfusion injury and prolong the period of safe lung preservation. The heart-lung block from 39 New Zealand white rabbits were harvested, flushed with 100 ml of a modified Collins solution, stored at 4 degrees C in a 30% inflation state, and reperfused with either whole blood or leukocyte depleted blood. Leukocyte depletion was accomplished using a blood filter and verified with selected leukocyte counts. Leukocyte readdition specimens were obtained from whole blood, the separation being done with hydroxyethyl starch and centrifugation at 4,000 rpm for five minutes. Six groups of rabbit lungs were studied. Group 1 consisted of control lungs that were not preserved and were reperfused with whole blood. Lungs in Group 2 underwent five-hour preservation and whole blood reperfusion. Lungs in Group 3 underwent five-hour preservation and leukocyte depleted blood reperfusion. Lungs in Group 4 underwent 24-hour preservation and leukocyte depleted blood reperfusion. Lungs in Group 5 also underwent 24-hour preservation, leukocyte depleted blood reperfusion, but with leukocyte readded at the onset of reperfusion. Lastly, lungs in Group 6 underwent 24-hour preservation, leukocyte depleted blood reperfusion, with leukocyte readdition after one hour of reperfusion. Group 5 showed pulmonary edema and complete reservoir emptying within the first hour of reperfusion. Group 2 had comparable poor results. Groups 3, 4, and 6 showed no significant differences from the control lungs in regard to pressure or reservoir loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1985

Long-term hemodynamics following combined heart and lung transplantation in primates.

To assess the long-term hemodynamic consequences of combined heart and lung transplantation, we investigated six rhesus monkeys 2.6 to 4.6 years (mean 4.0) after operation. Total follow-up was 24.0 primate-years. Autotransplantation had been carried out in four animals and allotransplantation in two, and the hemodynamic results were compared with those in three normal monkeys of similar size. Each animal underwent simultaneous right and left heart catheterization and pulmonary arteriography. Hemodynamic measurements were made at three levels of inspired oxygen. Arterial oxygen tension was within normal limits in all animals, and pulmonary artery pressure and pulmonary vascular resistance index did not change significantly with changes in the levels of inspired oxygen. Indices of left ventricular systolic function were normal in all animals. Values for pulmonary artery pressure and pulmonary vascular resistance index were similar in the autograft and normal groups: in the allograft group, the average pressure was 30/17 mm Hg (mean 24) and the index was 5.6 units . m2--both levels significantly higher than normal (pressure was 16/10 mm Hg, mean 13, [p less than 0.001] and index was 2.5 units . m2 [p less than 0.02]). Pulmonary arteriography in the allograft group with the highest pulmonary vascular resistance index (6.1 units . m2) was compatible with pulmonary vascular disease. Pulmonary arteriograms in the remaining eight monkeys were normal. Prolonged survival following combined heart and lung transplantation is possible in primates. Autotransplantation (and probable persisting denervation of the cardiopulmonary axis) does not necessarily result in abnormal long-term hemodynamics. The elevation in pulmonary artery pressure and pulmonary vascular resistance index in the allograft group may be related to previous episodes of pulmonary rejection, infection, or drug reaction.

Animals↗
PubMed1985

Cyclosporine in heart and heart-lung transplantation.

At Stanford University Medical Center from January 1968 until January 1984, 288 patients received 313 heart transplants. The immunosuppressive regimen before December 1980 consisted of azathioprine and prednisone, with or without rabbit antithymocyte globulin. After that time cyclosporine replaced azathioprine. In 92 recipients of 95 heart allografts, the 1- and 3-year survival rates were 82% and 65% to 70% respectively. In the 3 years from March 1981 to March 1984, successful heart-lung transplantation was accomplished in 13 of 19 recipients, using cyclosporine-based immunosuppression. Survival ranged from 1 to 38 months. While it is true that cyclosporine has improved survival in heart transplant recipients, has allowed successful heart-lung transplantation to be performed, has shortened intensive care unit and total hospital stays and therefore hospital costs, and has allowed easier management of rejection and infection, several disconcerting problems have not yet been resolved. These include hypertension that is difficult to control and renal dysfunction in all patients, and the fact that cellular and humoral rejection still occurs, as manifested by graft atherosclerosis, bronchiolitis obliterans and classic acute rejection. Better understanding and application of cyclosporine immunosuppression will undoubtedly minimize both cyclosporine- and non-cyclosporine-related postoperative complications and will improve survival even further.

Adult↗
PubMed1985

Heart and heart-lung transplantation: program, development, organization, and initiation.

Since the initiation of cardiac transplantation in 1967, more than 1,000 procedures have been done worldwide. A high percentage of these transplant procedures have been completed in the past few years. In 1983, II centers in the United States performed 173 transplant procedures; by 1984, there were more than 30 heart transplant centers. This sudden increase is due primarily to increasing survival of transplant recipients since the introduction of cyclosporine. However, most transplant surgeons believe that the use of this drug alone will not result in survival results and rehabilitation similar to those obtained in experienced transplant centers. Institutional commitment, adequate resources, attention to detail and most importantly, a dedicated transplant team, are important elements to ensure success. This manuscript will define guidelines for the establishment of a new transplant program and eludicate the organizational details necessary to implement such a program, based on our experience at the Johns Hopkins Hospital over the past two years.

Consumer Behavior↗
PubMed1985

Surgical repair of tetralogy of Fallot. Long-term follow-up with particular emphasis on late death and reoperation.

Early and late results in 309 patients undergoing repair of tetralogy of Fallot between 1960 and 1982 were analyzed with respect to independent determinants of operative mortality, late reoperation, and late death. Follow-up extended to 22 years and totaled 2,743 patient-years. The operative mortality rate was 4.9% +/- 1.3%. Multivariate logistic regression analysis revealed that only young age, long cardiopulmonary bypass time, and (probably) extent of right ventricular outflow tract patch were independent significant determinants of operative mortality. Patients who required a transannular right ventricular outflow tract patch and those who underwent repair without any outflow tract patch were at higher risk than those who received a separate right ventricular and/or pulmonary artery patch. The long-term results were highly satisfactory: Only 15% +/- 3% of patients required reoperation 13 years postoperatively, and 85% +/- 4% of discharged patients were alive 16 years later. Time-dependent linear stepwise multivariate discriminant analysis showed that extent of right ventricular outflow tract patch (transannular greater than none greater than right ventricular and/or [separate] pulmonary arterial), longer ischemic arrest time, previous palliative shunt, and primary suture closure of the ventricular septal defect were the only covariates that independently portended a higher likelihood of reoperation. Similarly, only older age, absence of hypoxic spells, and reoperation were significantly and independently related to the probability of late death. The results of these analyses demonstrate that intracardiac repair of tetralogy is a durable procedure for upwards of 20 years; however, high-risk subsets of patients can be identified in terms of operative mortality, reoperation, and late death. Thus, there is still a need for improvement, particularly future research devoted to better understanding of the electrophysiological mechanisms responsible for arrhythmias, electrosurgical and medical arrhythmia therapy, and right and left ventricular mechanics after repair of tetralogy of Fallot.

Actuarial Analysis↗
PubMed1984

Acute physiological changes following heart-lung allotransplantation in dogs.

The feasibility of clinical heart-lung transplantation requires a better understanding of the physiological consequences of the operation, heart-lung denervation, and the quality of graft preservation. An acute canine model was used to evaluate heart-lung function during the first 24 hours after transplantation. Measurements of cardiopulmonary dynamics were performed in 5 donor animals and compared sequentially after transplantation in the respective recipients. Orthotopic allotransplantation was performed on cardiopulmonary bypass with moderate hypothermia after perfusion of both the heart and lung with a clinical cardioplegic solution (4 degrees C; potassium chloride, 30 mEq/L; mannitol, 20 gm/L). Postoperatively, the animals were ventilated continuously and anesthetized. Hemodynamic variables were monitored, and measurements were made of arterial and venous oxygen, carbon dioxide, saturation, and pulmonary mechanics. Cardiac output and a derived measurement of lung water were determined. Pulmonary vascular resistance, arteriovenous shunt, resistance, and compliance were calculated. At the termination of the experiment, significant differences were observed between donor and recipient lung-water levels (7.7 +/- 0.9 ml/kg versus 12.0 +/- 3.1 ml/kg, respectively; p less than 0.05); 100% arterial oxygen tension (509 +/- 37 mm/Hg versus 227 +/- 114 mm/Hg, respectively; p less than 0.01); and pulmonary compliance (38 +/- 18 ml/cm H2O versus 11 +/- 4 ml/cm H2O, respectively; p less than 0.05). Arteriovenous shunt increased from 12.2 +/- 4 to 16.5 +/- 5% (p = 0.2). This model evaluates the technique currently employed clinically and will be used in the future to compare methods of heart-lung preservation with the goal of allowing distant heart-lung procurement.

Animals↗
PubMed1984

Heart-lung transplantation for irreversible pulmonary hypertension.

Combined heart and lung transplantation was carried out in 17 patients at Stanford University between March, 1981, and December, 1983. The recipients were between 22 and 45 years old. All patients had end-stage pulmonary hypertension; 10 had Eisenmenger's syndrome and the remaining 7, primary pulmonary hypertension. Five patients died within the first few postoperative weeks. The remainder are well between four weeks and 33 months from operation. The immunosuppressive protocol has consisted of cyclosporine with an initial course of rabbit antithymocyte globulin. Azathioprine also was given for the first two weeks and then was replaced with prednisone. Rejection, as diagnosed by cardiac biopsy, was treated with high doses of methylprednisolone. Modifications of technique that have developed include the removal of the recipient heart and lungs separately, and preservation of the lungs with a modified Collins' solution instead of a cardioplegic solution. Rejection occurred in 6 of the 12 survivors. Infections developed in 9 patients, but only one resulted in a fatal outcome (Legionella). Thus, the results of clinical heart-lung transplantation have been considerably superior to clinical efforts in lung transplantation. It is suggested that the combined operation is preferable for the following reasons: (1) all diseased tissue is removed, thus eliminating recurrent infection and ventilation/perfusion disparity; (2) transplantation of the entire heart-lung block preserves coronary-bronchial vascular anastomoses and makes airway dehiscence less likely; and (3) to date, diagnosis of rejection by cardiac biopsy has appeared to be a satisfactory method of diagnosing and treating pulmonary rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

A new technique for management of renal cell carcinoma involving the right atrium: hypothermia and cardiac arrest.

A 36-year-old man presented with massive edema below the axillae, pleural effusion and renal cell carcinoma with a tumor thrombus extending up the vena cava to the right atrium. A metastatic evaluation was negative otherwise. Hypothermia, cardiac arrest and temporary exsanguination in conjunction with cardiopulmonary bypass were used to create a bloodless field for excision of the renal cell carcinoma and its tumor thrombus. The patient has had total resolution of all symptoms and edema. Hypothermia and cardiac arrest facilitated greatly surgical excision and may be a useful adjunct in the excision of malignancies with massive involvement of the great vessels or heart.

Adenocarcinoma↗
PubMed1984

Immediate improvement of dysfunctional myocardial segments after coronary revascularization: detection by intraoperative transesophageal echocardiography.

To ascertain the immediate effects of coronary artery bypass grafting on regional myocardial function, intraoperative transesophageal two-dimensional echocardiograms were obtained in 20 patients using a 3.5 MHz phased array transducer at the tip of a flexible gastroscope. Cross-sectional images of the left ventricle were obtained at multiple levels before skin incision and were repeated serially before and immediately after cardiopulmonary bypass. Using a computer-aided contouring system, percent systolic wall thickening was determined for eight anatomic segments in each patient at similar loading conditions (four each at mitral and papillary muscle levels). Of the 152 segments analyzed, systolic wall thickening improved from a prerevascularization mean value (+/- SEM) of 42.7 +/- 2.9% to a postrevascularization mean value of 51.6 +/- 2.6% (p less than 0.001). Thickening improved most in those segments with the worst preoperative function (p less than 0.001). Chest wall echocardiograms obtained 8.4 +/- 2.3 days after operation showed no deterioration or further improvement in segmental motion compared with transesophageal echocardiograms obtained after revascularization. Thus: regional myocardial function frequently improves immediately after bypass grafting, with increases in regional thickening being most marked in those segments demonstrating the most severe preoperative dysfunction, and this improvement appears to be sustained; and in some patients, chronic subclinical ischemic dysfunction is present which can be improved by revascularization.

Aged↗
PubMed1984

Synthesis and glycosylation of the common alpha subunit of human glycoprotein hormones in mouse cells.

The synthesis and the post-translational modification of the alpha subunit of human glycoprotein hormones have been studied in a mouse cell. A full-length cDNA coding for the human alpha subunit has been expressed in mouse C127 cells under the control of mouse metallothionein regulatory sequences, using a bovine papilloma virus vector. Stable clones secreting the alpha subunit into the medium have been obtained. Two intracellular forms of 22,000 Da and 21,000 Da have been detected. Pulse-chase experiments suggest that the 22,000-Da form is exported, while the 21,000-Da form appears to remain intracellular. The secreted form of the alpha subunit migrates as a broad peak between 22,000 and 30,000 Da, suggesting further modification of the intracellular form prior to secretion. Both the secreted and the intracellular forms incorporate glucosamine label, indicating that at least a portion of the modification observed here is in the form of glycosylation.

Animals↗
PubMed1984

Clinical heart-lung transplantation.

Combined heart and lung transplantation was carried out in thirteen patients at Stanford University between March 1981 and May 1983. The recipients were between 22 and 45 years old. All patients were suffering from end-stage pulmonary hypertension; nine patients had Eisenmenger's syndrome; the remaining four were transplanted for primary pulmonary hypertension. Three patients died within one month of surgery. The remainder are well at between 22 months and three weeks from operation. The duration of stay in the hospital for the surviving patients ranged from 38 to 85 days. The immunosuppressive protocol has been essentially the same for all recipients, and has consisted of cyclosporine with an initial course of rabbit antithymocyte globulin (RATG) with azathioprine given for the first two weeks, and then replaced with prednisone. Rejection, as diagnosed by cardiac biopsy, was treated with pulses of methylprednisolone. Early complications included bleeding that necessitated reexploration (five patients); damage to the vagus, recurrent laryngeal, or phrenic nerves (three patients); and failure of the donor lungs (one patient). Modifications of technique that have developed include removal of the recipient heart and lungs separately, and preservation of the lungs with a modified Collins' solution instead of a cardioplegic solution. The results of this operation are considerably superior to clinical efforts in lung transplantation. The combined operation may be preferable for the following reasons: All diseased tissue is removed, thus eliminating recurrent infection, and also perfusion/ventilation disparity. Transplantation of the entire heart and lung block preserves coronary-tracheal vascular anastomoses and makes airway dehiscence less likely. Diagnosis of rejection by cardiac biopsy seems to be a satisfactory method of diagnosis and treatment of pulmonary rejection.

Adult↗