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Biomedical subjects

S A Hunt

Publications and source records attributed to S A Hunt.

At least 91 records · Page 5Linked to original sources
PubMed1982

Cardiovascular physiology in a case of heterotopic cardiac transplantation.

Successful heterotopic cardiac transplantation in a 24 year old man with end stage cardiomyopathy provided an opportunity to study cardiovascular physiology. The donor and native hearts, functioning independently in parallel, were studied by serial physical examination, electrocardiography, echocardiography, nuclear angiography and cardiac catheterization. Results indicated that the donor left heart assumed the predominant role in supplying systemic output, possibly contributing to decreasing function of the patient's own (native) heart. Analysis of serial nuclear angiograms revealed an initial postoperative ejection fraction of 52 and 21 percent in the donor and the native left ventricle, respectively; repeat studies 3 months postoperatively showed values of 50 and 9 percent, respectively, indicating significant deterioration in native left ventricular cardiac function. Observation of valve motion of the native heart showed major irregularities of the aortic valve in contrast to seemingly normal, regular mitral valve motion. These data rise interesting questions regarding interpretation of valve motion as an indicator of ventricular function.

Adult↗
PubMed1982

Heart-lung transplantation: successful therapy for patients with pulmonary vascular disease.

We report our initial experience with three patients who received heart-lung transplants. The primary immunosuppressive agent used was cyclosporin A, although conventional drugs were also administered. In the first patient, a 45-year-old woman with primary pulmonary hypertension, acute rejection of the transplant was diagnosed 10 and 25 days after surgery but was treated successfully; this patient still had normal exercise tolerance 10 months late. The second patient, a 30-year-old man, underwent transplantation for Eisenmenger's syndrome due to atrial and ventricular septal defects. His graft was not rejected, and his condition was markedly improved eight months after surgery. The third patient, a 29-year-old woman with transposition of the great vessels and associated defects, died four days postoperatively of renal, hepatic, and pulmonary complications. We attribute our success to experience with heart-lung transplantation in primates, to the use of cyclosporin A, and to the anatomic and physiologic advantages of combined heart-lung replacement. We hope that such transplants may ultimately provide an improved outlook for selected terminally ill patients with pulmonary vascular disease and certain other intractable cardiopulmonary disorders.

Adult↗
PubMed1981

Coronary artery spasm in the denervated transplanted human heart: a clue to underlying mechanisms.

The mechanism of coronary artery spasm has been poorly understood but there has been some suggestion that cardiac autonomic innervation may play an important role. We report coronary artery spasm in a 43 year old man two years after he had received a transplant. Provocative pharmacologic testing suggested functional denervation of the patient's heart. Thus, coronary artery spasm can occur in the transplanted, denervated human heart. Autonomic innervation of the heart is not essential in all cases of coronary spasm, and circulating catecholamines and/or metabolic of hormonal products may play an important role.

Adolescent↗
PubMed1981

Long-term survival and function after cardiac transplantation.

Cardiac transplantation now permits prolonged survival for some patients with otherwise fatal heart disease. This report summarizes the hemodynamic and clinical characteristics of 25 patients who have survived five or more years after cardiac replacement. The average age of the patients at the time of operation was 40 +/- 10 (SD) years; 23 were men. The average duration of survival is 6.7 years, and ranges from five to 10.5 years. Annual cardiac catheterization and clinical follow-up were performed to assess systolic cardiac function, coronary anatomy, and quality of extended rehabilitation. We found that among these long-term survivors, the left ventricular ejection fraction remained constant (0.59 +/- 0.08 one year postoperatively, 0.57 +/- 0.09 at most recent study, p = ns). Segmental wall motion measured by fluoroscopic examination of midwall intramyocardial markers also remained normal. Four of 21 (19%) patients with complete longitudinal studies developed significant graft coronary artery disease. Clinical evaluation revealed that the long-term survivors required fewer than one unscheduled admission to the hospital per year. Sixteen of 25 patients (64%) were gainfully employed, and 22 of 25 (88%) enjoyed substantial benefit in terms of extended rehabilitation. These 25 long-term survivors represent 27% of 92 patients transplanted between 1968 and 1975. The actuarial survival rate at five years, of patients transplanted since 1975, is 40 +/- 5%. This increase in survival rate reflects improved techniques of early postoperative management. Cardiac transplantation now offers prolonged survival with good quality of life for selected patients with terminal heart disease.

Adult↗
PubMed1981

Cardiac transplantation.

Based on the Stanford series of 188 patients, we emphasize that orthotopic cardiac transplantation represents a reasonable therapeutic option for the patient with inoperable end-stage heart disease. Current expectations for survival equal those for organ survival in cadaver renal transplant series and offer a rehabilitation potential of over 90%. Most of the complications limiting survival are due to the currently available means of immunosuppression and, therefore, advances in the field of immunosuppression can be expected to have a major positive influence on survival rates.

Arteriosclerosis↗
PubMed1976

Mitral valve prolapse in one hundred presumably healthy young females.

Clinical, electrocardiographic, phonocardiographic, and echocardiographic examinations were performed in 100 presumably healthy young females. Treadmill testing and ambulatory electrocardiographic monitoring were performed in a selected group of these subjects. Phonocardiograms, recorded with the subjects supine at rest, after inhalation of amyl nitrite, and in the upright position, revealed a 17% incidence of nonejection clicks and/or late or mid- to late systolic murmurs (PHONO-MSCLSM). Echocardiographic studies were performed in the second, third, fourth, and fifth intercostal space with emphasis on the importance of transducer angulation on the chest. Studies obtained with the transducer perpendicular to the chest in the sagittal plane, or pointing cephalad at a time when both mitral leaflets and left atrium are recorded, are optimal to study the mitral valve systolic motion. With the transducer in this position, 21 subjects were found to have pansystolic or late systolic prolapse, as previously defined on the echocardiogram. The presence of these echocardiographic findings was statistically related to the presence of PHONO-MSCLSM. Other echocardiographic patterns were identified and their relation to PHONO-MSCLSM and transducer position is discussed. Ten subjects with both echocardiographic evidence of mitral valve prolapse and PHONO-MSCLSM were identified (group EP), while 18 other subjects had either echocardiographic or phonocardiographic findings suggestive of mitral valve abnormality (group EorP). Seventy-two subjects had no abnormality (group noEP). The incidence of various clinical, electrocardiographic, and echocardiographic findings in these three groups was determined. Some findings said to be common in patients with proven mitral valve prolapse were seen more frequently in group EP subjects. Echocardiographic and phonocardiographic findings suggesting mitral valve abnormalities were found more commonly than expected in a population of presumably healthy young females.

Adolescent↗
PubMed1976

Infections after cardiac transplantation: relation to rejection therapy.

We have analyzed the relation of the treatment of 76 acute graft rejection episodes in 45 late postoperative cardiac transplant patients to the 56 infections occurring in these patients. Intensification of immunosuppressive therapy for acute rejection greatly increased the occurrence of infection from a control incidence of 1.3 infections per 1000 patient-days to a posttreatment incidence of 3.6. Two modes of treatment, increased oral prednisone and high-dose methylprednisolone plus antithymocyte globulin, were further analyzed. Actuarial analysis of infections after these two treatment modes showed that the treatment-related increase in infection was nearly exclusively due to the latter form of therapy. Invasive cardiac procedures did not appear to be causally related to infections in these immunocompromised patients.

Antilymphocyte Serum↗
PubMed1976

Does cardiac transplantation prolong life and improve its quality? An updated report.

The current status of the human cardiac transplant experience at Stanford University Medical Center is presented in order to reassess its role in the treatment of end-stage cardiac disease. Of 109 patients undergoing transplantation at Stanford between January 1968 and August 1976, 44 were still alive as of August 1, 1976. The overall 1- and 2-year survival rates for the series are 52% and 43%, respectively. Sixty-nine patients have survived more than 3 months, and their overall 1- and 2-year survival rates are 80% and 66%, respectively. Of the 3-month survivors, 62 (90%) returned to functional Class I New York Heart Association cardiac status and most of these returned to their pre-illness activities. Of 40 patients selected for transplantation for whom a donor did not become available, 38 were dead in less than 6 months. Complications related to immunosuppression with steroids are currently the major barrier to longer survival and improved rehabilitation postransplantation. On the basis of these data we conclude that cardiac transplantation not only prolongs survival, but can return carefully selected recipients to an active life.

Adolescent↗
PubMed1975

The status of cardiac transplantation, 1975.

Since December 1967, 263 human cardiac transplant operations have been performed throughout the world. Eighty-two of these were performed at Stanford University Medical Center, In 1974, 27 such operations were performed, 15 at Stanford Survival rates for the entire Standford series are 48% at one year and 25% at three years; survival rates at one and three years for patients surviving the first three critical months after transplantation are 77% and 42%, respectively. Recipients under the age of 55 years, with New York Heart Association Class IV cardiac disability, are selected for transplant procedures according to criteria dictated by experience over the past seven years. A routine immunsuppressive regimen for organ transplantation, incorporating prednisone, azathioprine, and antithymocyte globulin is employed early postoperatively, and prednisone and azathioprine are used for indefinite maintenance therapy. Acute cardiac graft rejection in nearly all recipients is diagnosed by clinical signs, electrocardiographic changes, and percutaneous transvenous endomyocardial biopsy. Ninety-five percent of acute rejection episodes are reversible with appropriate immunosuppressive treatment, but infectious complications are common and have accounted for 56% of all postoperative deaths. The Stanford experience in cardiac transplantation has demonstrated the potential therapeutic value of this procedure. Maximum survival now extends beyond five years. Satisfactory graft function has been documented in long-term surviving patients, the majority of whom have enjoyed a high degree of social and physical rehabilitation.

Acute Disease↗
PubMedDate not supplied

Neoplasia after heart transplantation.

Transplant recipients have a higher incidence of cancer compared with the general population. This increased risk is related to the intensity and chronicity of immunosuppression that these patients receive. The common types and presentations of posttransplant tumors are reviewed and discussed. Regular surveillance is of paramount importance in detecting such tumors. Treatment invariably includes attempts to reduce immunosuppression.

Heart Transplantation↗
PubMedDate not supplied

Who and when to consider for heart transplantation.

The number of patients who are potentially eligible for heart transplantation is increasing steadily in the face of a plateaued or stable donor supply. Therefore, development of fair, sensible, and consistently and widely applied criteria for transplant recipient selection is a crucial medical and societal issue. This article examines the evolution of these criteria and advocates a flexible approach to their continued evolution.

Heart Transplantation↗
PubMedDate not supplied

New immunosuppressive agents in clinical use: mycophenolate mofetil and tacrolimus.

Since the early 1980s, a 3-drug regimen that includes cyclosporine, azathioprine, and usually corticosteroids has been the mainstay of immunosuppression for patients undergoing cardiac transplantation. This regimen, however, has a variety of inherent toxicities and is not associated with any lesser incidence of graft coronary artery disease than the earlier regimen. For these reasons, there has been a widely perceived need for the introduction of improved immunosuppressive agents. Two such agents have thus far been introduced into clinical organ transplantation: mycophenolate mofetil and tacrolimus. Mycophenolate mofetil is used as a substitute for azathioprine and has been shown to result in significantly lower mortality rates and freedom from rejection in heart transplant recipients. Tacrolimus can be used as a substitute for cyclosporine but (at least in the short-term) seems to offer no important advantage in terms of survival or rejection. The combination of these 2 new agents seems to have no short-term disadvantage and longer-term follow-up is pending.

Drug Therapy, Combination↗
PubMedDate not supplied

Impact of proximal or midvessel discrete coronary artery stenoses on survival after heart transplantation.

To assess survival after the development of transplant coronary artery disease, annual angiography reports from 353 heart transplant recipients were reviewed. Fifty-four patients who survived beyond 1 year and in whom moderate-to-severe proximal or midvessel coronary artery disease developed were identified. Moderate-to-severe proximal or midvessel coronary disease was defined for this study as a 40% or more stenosis in 1 or more primary or secondary epicardial arteries. Actuarial survival (Kaplan-Meier) from the time of disease detection in those 54 patients was 67% at 1 year, 44% at 2 years, and 17% at 5 years. Actuarial survival was reduced proportionate to disease severity. Survival for single-vessel disease (> or = 40% stenosis) was 64% at 1 year, 36% at 2 years, and 22% at 5 years. Survival was significantly worse with triple-vessel disease (13% at 2 years; p = 0.01) and intermediate for double-vessel disease (41% at 2 years; p = 0.01). Of 19 patients who underwent retransplantation for coronary artery disease, 13 patients (68%) died at a mean of 24 +/- 20 months (range, 1 to 59), and of 15 patients from whom postmortem or angiographic data were available, 11 patients (73%) showed recurrence of significant coronary artery disease in the new graft. Identification of moderate or severe proximal or midvessel coronary disease at angiography predicts an overall mortality rate of more than 50% at 2 years. The poor survival rate in those who underwent retransplantation (around 50% at 4 years) and the high rate of redevelopment of coronary disease suggest that retransplantation should be reserved for selected candidates with angiographically severe disease, if used at all.

Adolescent↗