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Biomedical subjects

W A Gay

Publications and source records attributed to W A Gay.

At least 37 records · Page 2Linked to original sources
PubMed1992

Mediastinitis in heart transplantation.

Between March 1985 and December 1991, mediastinitis developed in 12 of 420 cardiac transplantation patients (2.8%). The mortality rate in this group of patients was 8.3% (1/12). Actuarial survival (1 year, 75%; and 5 years, 65%) was not significantly different from that of the group without mediastinitis (1 year, 88%; and 5 years, 75%). A higher percentage of the patients in the group with mediastinitis were listed as UNOS status 1 (50% versus 35%) and had a history of previous sternotomies (58% versus 44%). The presentation of mediastinitis was typical. Computed tomographic scanning with or without aspiration was a valuable adjunct in the diagnosis of mediastinitis. Induction immunotherapy with minimal steroids in the perioperative period was used in all patients. This may contribute to the patients' ability to mount an appropriate and effective response to infection, permitting earlier diagnosis. The debridement irrigation technique used in 8 of 12 patients had a low success rate of 33%, whereas the debridement muscle flap technique used in 4 of 12 was 100% successful in eliminating infection.

Actuarial Analysis↗
PubMed1992

Cardiac retransplantation: a viable option? The Registry of the International Society for Heart and Lung Transplantation.

To evaluate cardiac retransplantation as an appropriate utilization of scarce donor organs we analyzed data from the registry of the International Society for Heart and Lung Transplantation (ISHLT) (n = 449) and the Utah Cardiac Transplant Program (n = 20). Actuarial survival among retransplants was lower than in patients who received only one transplant in both the ISHLT registry patients (1 year survival, 48% versus 78%; p = 0.001) and the Utah series (1 year survival, 74% versus 88%; p = 0.06). Uncontrolled rejection, short interval (< 6 months) between transplantations, and the need for mechanical circulatory support were identified as risk factors for retransplantation. The incidence of rejection and infection was similar in first and second transplant recipients. Second transplant recipients had a higher level of sensitization, a greater incidence of donor-specific positive crossmatches, and an increased early mortality. Repetition in the second donor of mismatched HLA antigens present in the first donor did not adversely affect survival. If patients who underwent retransplantation within 6 months of their initial transplantation, those receiving transplants for uncontrolled rejection, and those requiring mechanical assistance were eliminated from the study, the short-term and long-term survival after cardiac retransplantation does not differ from that in patients having a single transplant.

Actuarial Analysis↗
PubMed1990

Cardiac allograft function with corticosteroid-free maintenance immunosuppression.

Potent prophylactic immunosuppressive protocols promote the safe withdrawal of corticosteroid maintenance. The benefits of corticosteroid-free maintenance immunosuppression include the absence of the cushingoid habitus, fewer infections, less obesity, and lower serum cholesterol. The incidence of allograft coronary artery disease is not increased by corticosteroid-free maintenance. To assess the long-term effects of corticosteroid-free immunosuppression on allograft function, we compared results of hemodynamic study and noninvasive evaluation over the 2-year follow-up of 57 patients on corticosteroid-free maintenance to 40 patients who required corticosteroid. Age and pretransplantation diagnoses were similar, but a greater percentage of those who required corticosteroid maintenance were female (28% versus 2%, p less than 0.001). Indexes of allograft function were similar in both groups and these indexes included ejection fraction, right atrial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac index, left ventricular end-diastolic dimension, and posterior wall thickness. Patient survival was identical in the two groups (98%). These data indicate that corticosteroids can be safely withdrawn with the subsequent early benefits and without compromising long-term allograft function.

Antibodies, Monoclonal↗
PubMed1990

Influence of corticosteroid-free maintenance immunosuppression on allograft coronary artery disease after cardiac transplantation.

Although the etiology of allograft coronary artery disease, a major limiting factor in long-term survival after cardiac transplantation, is poorly understood, it is undoubtedly in part immune mediated and not detected by routine endomyocardial biopsy. Therefore it is possible that withdrawal of maintenance corticosteroids, although providing other short- and long-term benefits, could increase the prevalence of allograft coronary artery disease by permitting undetected immune-mediated vascular injury to occur. To assess whether corticosteroid-free maintenance immunosuppression increased the prevalence of allograft coronary artery disease, we reviewed serial angiograms of 102 patients (49% not receiving corticosteroid maintenance therapy) who underwent heart transplantation after March 7, 1985. Multiple variables including serum cholesterol, recipient and donor age, sex, blood pressure, rejection frequency and severity, early rejection prophylaxis protocol (polyclonal versus monoclonal T-cell agents), and corticosteroid use were examined in relation to allograft coronary artery disease by univariate and multivariate analyses. Allograft coronary artery disease was identified in 21 patients (seven severe, four moderate, and 10 mild). The prevalence by Kaplan-Meier life-table analysis was 17% at 1 year and 25% at 2 years. No further allograft coronary artery disease was detected among patients undergoing angiography at three years. Increased allograft coronary artery disease was not noted in patients withdrawn from maintenance corticosteroids when compared with their corticosteroid-requiring counterparts. In fact, with each 1 gm increment in cumulative corticosteroid use, a slightly increased risk (1.04, p less than 0.05) of allograft coronary artery disease was noted (Cox regression model). None of the other variables correlated with the prevalence of allograft coronary artery disease. Thus withdrawal of maintenance corticosteroids is not associated with an increased risk of early allograft coronary artery disease and minimization of corticosteroids may lead to a decreased long-term incidence of coronary artery disease in cardiac transplant recipients.

Adrenal Cortex Hormones↗
PubMed1989

Major abdominal complications following cardiac transplantation. Utah Transplantation Affiliated Hospitals Cardiac Transplant Program.

Serious complications involving the alimentary tract are commonly reported following cardiac transplantation, and may be associated with significant morbidity and mortality. The aim of this report was to review the incidence, severity, and outcome of abdominal complications in our heart transplant population in whom we used corticosteroid-sparing protocols for immunosuppression. From March 1985 through September 1988, 178 patients underwent 185 cardiac transplants. Twenty-six cardiac transplant recipients (15%) sustained 33 major abdominal complications, including gastrointestinal bleeding (n = 8), pancreatitis (n = 8), bowel perforation (n = 6), cholecystitis (n = 4), and miscellaneous other problems (n = 7). Operative therapy was required in 61% of cases. No deaths were caused by the gastrointestinal complications of their operative management. Corticosteroid-sparing immunosuppression may be responsible for the low incidence of abdominal morbidity, and early, aggressive surgical intervention may reduce subsequent mortality.

Adult↗
PubMed1989

Potassium-induced cardioplegia: evolution and present status.

Most cardiac surgical procedures performed in 1989 are accomplished with the aid of some type of controlled, chemically induced cardiac standstill. Although the physiological principles involved were described in the late 19th century, the first clinical application was not until 1955. Because many surgeons believed that myocardial injury resulted from the toxicity of the agents used, the technique was largely abandoned for about 15 years. With the increasing volume of coronary revascularization surgery and with the need for protection of donor hearts intended for orthotopic transplantation, chemically induced cardiac standstill became more appealing and the technique was revived and reevaluated in several centers. In the last several years, the constitution of cardioplegic solutions and the methods by which they are delivered have been greatly modified. Although the most effective solution and technique may yet remain to be described, unquestionably controlled chemically induced cardiac standstill has contributed substantially to the ease and safety with which cardiac surgical procedures can be accomplished. This vignette, although far from complete, outlines some of the important works that have contributed to the evolution of cardioplegic techniques.

Animals↗
PubMed1989

Efficacy of OKT3 retreatment for refractory cardiac allograft rejection.

Although OKT3 monoclonal antibody is a useful therapy for refractory cardiac allograft rejection, the use of OKT3 for prophylaxis may be limited by the potential of sensitization and subsequent loss of efficacy on retreatment. OKT3 was required for refractory rejection in 21 of 165 recipients transplanted between March 1985 and August 1988. Twelve of these patients had previously been exposed to OKT3, and the retreatment efficacy was evaluated. The study population averaged 42.1 +/- 15.3 years of age (mean +/- SEM) and had experienced 2 +/- 1 previous episodes of rejection. The prior episodes of rejection had been treated with pulse methylprednisolone and antithymocyte globulin, and in addition 3 patients (25%) also required a course of antilymphoblast globulin. Retreatment OKT3 for refractory rejection was required 120 +/- 94 days following transplantation. CD3+ lymphocytes were eliminated from the circulation within 24-48 hr in 11 of 12 patients, all of whom showed histologic improvement within the first week. Total resolution on the initial follow-up biopsy was noted in 9 (75%) during the course of therapy. Subsequent rejection episodes occurred in 9 (82%) of the survivors at 71 +/- 64 days. One-year survival was 83% in this vigorously rejecting patient population. Serious infections occurred within 3 months of therapy in 4 (36%). The side effects of OKT3 retreatment were similar to those seen with first exposure and did not require OKT3 discontinuation. Thus OKT3 may be administered with success in most patients who have previously been exposed to it.

Adult↗
PubMed1989

Preservation of myocardial ultrastructure after 24 hours of Klebsiella sepsis: histologic, functional, and biochemical correlations.

Myocardial function with ultrastructure and high energy phosphate levels in dogs was correlated after 24 hours of sepsis using live Klebsiella aerogenes. All animals developed progressive hemodynamic deterioration over a 24 hour period. Mean arterial pressure decreased from 148 +/- 7 mmHg to 85 (P less than 0.01) and cardiac output decreased from 3.43 +/- .31 to 1.6 +/- 0.5 L/min. Left ventricular stroke work decreased from 48.2 +/- 5 to 18.1 +/- 6 gm-meters (P less than 0.001). Systemic and pulmonary vascular resistances were increased at 24 hours (3,538 +/- 27 to 7,404 +/- 1,400 dyne/sec/cm-5 (P less than 0.01), and 185 +/- 20 and 619 +/- 90 dyne/sec/cm-5 (P less than 0.001), respectively. Left ventricular function curves at 24 hours showed a fixed low output. However, myocardial ultrastructure was preserved and high energy phosphate levels remained normal. These observations correlate well with the changes seen clinically in early gram negative sepsis in hypovolemic patients. Thus, this appears to be a suitable model for further investigation of the effects of gram negative sepsis on myocardial performance, ultrastructure, and maintenance of energy stores.

Animals↗
PubMed1988

The rabbit autoperfusing heart-lung preparation.

The autoperfusing heart-lung preparation holds promise as a method for extended organ preservation. Further understanding of the hemodynamics, metabolism, and quality of tissue preservation of this preparation may increase the number of available organs for heart-lung transplantation. We describe the materials and operative technique for a small animal model of the autoperfusing heart-lung preparation. The method is easy to learn, the materials and animal subjects are inexpensive, and the preparation is fully monitored to provide consistent and reproducible data. The rabbit autoperfusing heart-lung preparation is an excellent vehicle for the investigator studying warm organ preservation.

Animals↗
PubMed1988

OKT3 monoclonal antibody in cardiac transplantation. Experience with 102 patients.

OKT3 is a murine monoclonal antibody that is reactive against the CD3 surface antigen on T lymphocytes. This antigen appears to be essential for recognition of foreign antigen and for initiation of the process of cell-mediated rejection. One hundred and two patients having orthotopic cardiac transplantation in a single program during a 3-year period received prophylactic immune suppression with OKT3, along with azathioprine and low-dose steroids. Patients began receiving cyclosporine on Day 11; steroid-weaning was attempted 3 weeks after transplantation. In this group of patients, the time to the first rejection was 76 +/- 11 days (mean +/- SEM), and 85% were successfully weaned from maintenance steroids. Avoidance of the side effects of cyclosporine and/or high dose steroids during the perioperative period, combined with a long rejection-free interval and the likelihood of long-term maintenance free of steroids, make the use of OKT3 or similar agents an attractive alternative to conventional immunosuppression.

Antibodies, Monoclonal↗
PubMed1988

Effect of preoperative hemodynamic support on survival after cardiac transplantation.

The accessibility and success of cardiac transplantation promotes transplantation for a broad range of recipients, including those requiring intravenous inotropes or mechanical-assist devices. To determine if survival is dependent on preoperative requirements for hemodynamic support, we studied 230 patients who underwent transplant at the Loyola, Stanford, and UTAH programs from December 1, 1984 through November 30, 1986, and who were followed up for 34 months postoperatively. Group 1 (n = 132 of 230, 57%) patients required only oral medical therapy to maintain hemodynamic compensation; Group 2 (n = 69 of 230, 30%) patients were dependent on intravenous inotropic support; and Group 3 (n = 29 of 230, 13%) patients required mechanical assistance. Pretransplant characteristics showed that dilated cardiomyopathy was more common in Group 2 patients, and lower cardiac index and ejection fraction were more prevalent in Group 3 patients as expected. Although survival was lower in Group 3 only at 1 month (Group 1, 98.5%; Group 2, 92.8%; and Group 3, 86.2%; p less than 0.01), the survival advantage in Groups 1 and 2 was lost by 3 months, with 1-year survival rates of 88.6% in Group 1, 81.2% in Group 2, and 82.8% in Group 3. Allograft survival and cause of death were not different among the three groups. Acute rejection occurred at a lower monthly frequency in the first 4 months in Group 3 (Group 1, 0.47 +/- 0.03; Group 2, 0.47 +/- 0.05; and Group 3, 0.29 +/- 0.06; p less than 0.01), whereas infectious complications occurred at similar frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Assisted Circulation↗
PubMed1988

Echocardiographic evaluation of potential cardiac transplant donors.

Since the initiation of the UTAH Cardiac Transplant Program, echocardiography has been used to evaluate 74 potential donors including 65 of 71 hearts ultimately used for transplantation. Of these 65 donors, 46 had normal studies, nine had pericardial effusions, five had mild septal hypokinesia with otherwise normal function, four had equivocal mitral valve prolapse, and only one heart could not be visualized. All transplants were successful and all donor hearts exhibited satisfactory hemodynamic function immediately after transplantation, including the hearts that were mildly abnormal before transplantation. These hearts included 21 (29%) that could have been excluded by conventional screening criteria. Nine potential donor hearts with grossly abnormal echocardiograms were not used for transplantation, including eight hearts with severe hypokinesia and one heart with significant mitral and tricuspid regurgitation. Inspection or histologic analysis confirmed the presence of severe dysfunction or morphologic damage in those hearts subjected to these additional measures. We conclude that echocardiographic screening is a useful method of evaluating potential cardiac transplant donors. It can identify potential donors that would otherwise have been excluded and it can identify potential donors with severe cardiac dysfunction without the need for direct surgical inspection.

Adult↗