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Biomedical subjects

S A Hunt

Publications and source records attributed to S A Hunt.

At least 73 records · Page 4Linked to original sources
PubMed1988

Accelerated coronary vascular disease in the heart transplant patient: coronary arteriographic findings.

Annual coronary arteriograms have been obtained from all heart transplant recipients at Stanford University Medical Center since 1969. Angiographic lesions in 81 transplant patients exhibiting coronary vascular disease were classified into three categories: type A, discrete or tubular stenoses; type B, diffuse concentric narrowing; and type C, narrowed irregular vessels with occluded branches. The 81 arteriograms showing transplant coronary vascular disease were contrasted with 32 from nontransplant patients with coronary artery disease analyzed in a similar fashion. The nontransplant angiograms showed 178 lesions, all of type A (discrete or tubular) morphology, 75% of which were located in primary epicardial coronary vessels and 25% in secondary branch vessels. In the patients with transplant coronary vascular disease, 349 (76%) of 461 lesions were type A: 57% in primary vessels, 42% in secondary branches and 1.4% in tertiary branches. Of the 112 type B and C lesions (diffuse narrowing, tapering and obliteration), 25% were in primary vessels, 44% in secondary vessels and 31% in tertiary branches (p less than 0.05 for patients with transplant coronary vascular disease versus patients with nontransplant coronary artery disease). Total vessel occlusion was found in proximal or middle vessel segments in 96% and distally in 4% of patients with "ordinary" coronary artery disease versus 49% distally in patients with transplant coronary disease (p less than 0.002). In the presence of total vessel occlusion, collateral vessels were poor or absent in 92% of transplant versus 7% of nontransplant patients with coronary disease (p less than 0.002). Therefore, coronary artery disease in transplant patients represents a mixture of typical atheromatous lesions and unique transplant-related progressive distal obliterative disease that occurs without collateral vessel development.

Cardiac Catheterization↗
PubMed1988

Noninvasive assessment of donor and native heart function after heterotopic heart transplantation.

The contribution of the donor heart to total circulatory performance after heterotopic heart transplantation has been difficult to assess. First-pass nuclear angiocardiography and directional Doppler echocardiography were used to examine separately left and right ventricular function of the donor heart after heterotopic transplantation. A comparison was made between two patients, one with a low initial pulmonary vascular resistance and one with a high, relatively fixed pulmonary vascular resistance. In both cases, currently available noninvasive techniques allowed confirmation of the expectation that the donor left ventricle can function effectively as a left ventricular bypass. In neither case was recovery of the native heart demonstrated. The contribution of the donor right ventricle to total right ventricular output appeared to be dependent on the condition of the donor heart and on the pulmonary vascular resistance. In situations with a high pulmonary vascular resistance and end-stage right ventricular failure, it was concluded that the donor heart may not at first constitute an effective assist for the native right ventricle. Native right ventricular failure may then become a major factor influencing survival after heterotopic heart transplantation.

Adolescent↗
PubMed1987

Influence of recipient atrial contraction on left ventricular filling dynamics of the transplanted heart assessed by Doppler echocardiography.

Recipient atrial remnants retain electrical and mechanical activity after orthotopic cardiac transplantation. This study investigated the influence of recipient atrial contraction timing on Doppler ultrasound mitral flow velocity curves, isovolumic relaxation time, peak early mitral flow velocity (M1), mitral valve pressure half-time and peak mitral flow velocity due to atrial systole (M2). Clearly identifiable recipient atrial electrical activity (P waves) was present in 7 of 10 patients studied early postoperatively 2 to 6 months (mean 2.5) (early group) and in 20 of 24 patients seen 1 to 11 years (mean 3) after transplantation (late group). Median age and gender distribution were similar in both groups. For analysis of its influence on isovolumic relaxation time, pressure half-time and M1, recipient atrial contraction was classified by its position in the cardiac cycle as early systole, late systole or diastole. For analysis of M2, it was classified as early diastole, late diastole or systole. Compared with its occurrence in diastole, recipient atrial contraction in late systole was associated with a shorter isovolumic relaxation time, shorter pressure half-time and higher M1. In early systole it was associated with a longer pressure half-time and lower M1 than in diastole; isovolumic relaxation time was unchanged. Recipient atrial contraction in early diastole resulted in a lower M2 than in systole, whereas simultaneous contraction of recipient and donor atria in late diastole resulted in an increase in M2. These results indicate that the timing of recipient atrial contraction and relaxation significantly influences left ventricular filling dynamics.

Adult↗
PubMed1987

Hypoxic pulmonary vasoconstriction persists in the human transplanted lung.

The preservation of hypoxic pulmonary vasoconstriction (HPV) in the denervated lung was studied in five human heart-lung transplant recipients. All five patients showed significant increases in mean pulmonary artery pressure and pulmonary vascular resistance during hypoxic exposure, returning toward normoxic values during recovery. Aside from PAO2 and Pao2, other factors known to influence pulmonary vascular resistance did not change significantly during the hypoxic period. There was no relation between the length of the post-transplantation period and the intensity of HPV, suggesting that reinnervation of the pulmonary vascular bed did not account for persistent HPV and that HPV persists in the human transplanted lung despite the loss of autonomic neural innervation.

Adult↗
PubMed1987

Cardiac transplantation in children and adolescents.

Cardiac transplantation represents an expanding therapeutic modality for end-stage heart disease in children and adolescents. During the past 5 years, 27 patients (15 boys; 12 girls) between the ages of 2 and 18 have undergone cardiac transplantation. The preoperative diagnosis was cardiomyopathy in 24 (six familial), congenital heart disease in two, and endocardial fibroelastosis in one. Immunosuppression included cyclosporine, azathioprine, and prednisone. There were 22 survivors, with four hospital deaths (three infection, one pulmonary hypertension), and one death at 4.5 years from graft atherosclerosis. The actuarial survival at 4 years was 83 +/- 7.4% and that at 5 years was 69 +/- 14.2%. Renal function was stable at 4 years, with an average creatinine clearance of 69.75 +/- 27.0 ml/min/m2. Hypertension was present in 21 of 22 patients, who require multiple drug therapy. Rehabilitation is 100% among discharged patients, with 14 in school, six employed, and two toddlers.

Adolescent↗
PubMed1987

Clinical and laboratory correlates of accelerated coronary artery disease in the cardiac transplant patient.

Accelerated coronary disease in the cardiac allograft (TxCAD) is a major complication affecting long-term survival of heart transplant patients. Since the transplanted heart remains denervated, the first sign of TxCAD may be silent myocardial infarction or sudden death. The prevalence of this disease has been unaltered since the advent of cyclosporine immunosuppression. Serial annual coronary arteriograms in 132 patients undergoing transplantation after 1979 at Stanford revealed 44 patients who developed TxCAD (33%). Multiple variables, including patient lipid profile, extent of donor and recipient tissue match, age of recipient and donor, number of rejection episodes, prednisone dose, and fasting blood sugar were examined in relation to occurrence of TxCAD. Donor age was greater among the 44 patients developing TxCAD that in the 88 patients who did not develop coronary artery disease (23.5 +/- 5.8 vs 21.3 +/- 5.7 years, p less than .05). The fasting plasma triglyceride level 1 year after transplantation was 236.0 +/- 246.3 mg% in the patients with TxCAD vs 170.1 +/- 108.2 mg% in those without TxCAD (p less than .05). No other indexes, including number of rejection episodes during first posttransplant year, number of HL-A mismatches, level of maintenance steroids, fasting blood sugar, and cholesterol subfractions identified patients who developed TxCAD. We conclude that TxCAD has limited correlation with the clinical and laboratory factors analyzed. Higher donor age and elevated plasma triglycerides may be significant predisposing factors for the development of TxCAD.

Adult↗
PubMed1987

Changes in Doppler echocardiographic indexes of left ventricular function as potential markers of acute cardiac rejection.

Changes in left ventricular filling and ejection as potential markers of cardiac allograft rejection were evaluated by serial Doppler echocardiography performed in 23 normal volunteers and within 24 hr of endomyocardial biopsy in 22 patients aged 14 to 53 years (mean 37). Peak aortic velocity, left ventricular ejection time index (ETI), isovolumic relaxation time (IVRT), mitral valve pressure half-time (PHT), peak early mitral flow velocity (M1), and velocity following donor atrial systole (M2) were measured without prior knowledge of endomyocardial biopsy findings. Biopsy specimens were graded histologically as: no rejection, mild rejection (cellular infiltrate), and moderate rejection (myocyte necrosis). A total of 120 biopsy-correlated Doppler echocardiographic studies were performed during 16 weeks after cardiac transplantation. Heart rate and mean arterial pressure were significantly higher in transplant recipients than in normal subjects. IVRT and PHT were significantly longer, while M1 and M2 were similar. Peak aortic velocity was higher in normal subjects than in transplant recipients, while ejection time was similar. Rejection of increasing severity was associated with a progressive shortening of IVRT and PHT and with an increase in M1 (p less than .0005 for all comparisons). Peak aortic velocity and ejection time index did not change significantly with rejection. These data indicate that acute cardiac rejection is accompanied by alteration in left ventricular filling dynamics detectable by Doppler echocardiography, without measureable changes in systolic function. These changes may provide noninvasive markers for surveillance of rejection.

Acute Disease↗
PubMed1985

Accelerated atherosclerosis in a cardiac transplant patient.

A cardiac transplant patient with rapidly progressive graft atherosclerosis is described. This case demonstrates the accelerated nature of this disease and problems in diagnosis, as well as an unexpected and previously unreported lack of sensitivity of exercise thallium scintigraphy in its investigation. This case also gives further support to the practice of routinely and frequently obtaining coronary arteriograms in the management of these patients.

Adult↗
PubMed1985

Long-term results, hemodynamics, and complications after combined heart and lung transplantation.

During the first 31/2 years of the Stanford heart-lung transplant program, 23 transplants have been carried out in 22 patients with severe pulmonary vascular disease. Actuarial survival curves predict 1 and 2 year survival rates of 71% and 57%, respectively, for all patients. As a result of increasing experience, the early mortality of 26% has been reduced, with only one early death occurring in the last eight patients; prior cardiac surgery was a contributing factor in three of the six patients suffering early deaths. Two late deaths occurred in the series 14 and 15 months after operation. One patient died suddenly as a result of an acute myocardial infarct and the other patient died because of respiratory failure. At autopsy, both patients had severe proliferative coronary atherosclerosis with obliterative bronchiolitis affecting the lungs. An additional patient required a retransplant for obliterative bronchiolitis 37 months after the initial procedure, and he too was found to have severe coronary artery disease. Hemodynamics and left ventricular function were normal in patients studied 1 and 2 years after undergoing the transplantation procedure. Thus, the early mortality and morbidity of combined heart and lung transplantation has been significantly reduced, but the long-term complications, particularly graft atherosclerosis and obliterative bronchiolitis, are yet to be fully controlled.

Actuarial Analysis↗
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↗
PubMed1984

Physiologic aspects of human heart-lung transplantation. Pulmonary function status of the post-transplanted lung.

Pulmonary function measurements were performed before and after heart-lung transplantation in nine patients who had undergone surgery for end-stage pulmonary hypertension. In seven of them, sequential follow-up studies were performed at variable times postoperatively with the longest period 27 months. Pre-transplant studies showed a mild restrictive defect in 33 percent and obstructive disease in 50 percent of the patients, respectively. Arterial hypoxemia was present in all patients. The degree of mechanical changes found did not appear severe enough to account for the marked dyspnea and disability characterizing this group of patients with pulmonary hypertension. Following transplantation, all patients showed striking improvement of symptoms and general physical status. In the early post-transplant period, there was a marked decrease in most lung volumes resulting in a moderately severe restrictive ventilatory defect. Flow parameters that were reduced could be related to decreased volumes and not to intrinsic airway obstruction. Arterial O2 tensions improved dramatically and gas exchange was maintained at essentially normal levels. Lung function tended to improve progressively following transplantation with the passage of time. Heart-lung transplant is consistent with an adequate long-term pulmonary functional state which has the capacity to sustain the normal activities of daily living. From the standpoint of lung function, heart-lung transplantation appears to be acceptable as a form of therapy in selected patients.

Adult↗
PubMed1984

Functional and social rehabilitation of heart transplant recipients under age thirty.

In the Stanford Heart transplant program, the functional and social rehabilitation of heart transplant recipients below the age of thirty has been investigated by using data from annual follow-ups with right and left heart catheterization, left ventricular (LV) and coronary angiograms and by a health survey questionnaire investigation. 24 out of 38 patients who received transplants in the period January 1, 1974 to April 1981 were still alive. The actuarial survival rates in this group of patients are: 3 months 74%; 1 year 71%, 3 years 67%, 5 years 50%. The figures are persistently higher than for the total number of heart transplant recipients in the Stanford program. 71% of the fatalities occurred during the critical first 3 months after transplantation. The hemodynamic and angiographic findings were normal in all but 2 patients where progressive coronary artery disease had been diagnosed. 23 out of the 24 patients completed the questionnaire. 9 patients were back at work, 4 went to school as required, 4 were now postgraduate students, 2 studied for self-satisfaction and 4 patients neither worked nor studied. All patients considered themselves able to do some kind of work. All patients were able to walk at least 1 mile and 70% 3 miles. 87% were able to do heavy domestic work. Hardly any restrictions in transportation ability and mostly minor restrictions in the activities of daily living were found. Marital satisfaction and sexual function were good in most of the patients; 57% were very satisfied, 30% moderately satisfied and 13% not really satisfied with their life.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1983

Diagnosis and treatment of allograft rejection in heart-lung transplant recipients.

Six patients received heart-lung transplants between March, 1981, and January, 1982. There were four women and two men between 26 and 45 years of age, three with primary pulmonary hypertension and three with congenital heart disease and pulmonary hypertension (Eisenmenger's syndrome). Immunosuppression was primarily with cyclosporin-A, with additional corticosteroid, azathioprine, and rabbit antihuman thymocyte globulin. Six episodes of allograft rejection in four patients (10, 11, 21, 24, 53, and 86 days after transplantation) were detected by means of transvenous endomyocardial biopsy. All patients experienced pulmonary edema early after transplantation (reimplantation response), and two patients required mechanical ventilatory support for allograft rejection at 10 and 11 days. Treatment of rejection consisted of intravenous methylprednisolone (four episodes) or augmented oral prednisone (two episodes), with resolution. No episode thought to be pulmonary rejection has occurred in the absence of cardiac findings. Four patients are alive from 6 to 15 months after transplantation and are functionally normal. Early experience with heart-lung transplantation suggests (1) that allograft rejection can be detected by cardiac findings and successfully treated by augmented corticosteroids, (2) that lung rejection does not occur in the absence of cardiac findings, (3) that the frequency and severity of rejection episodes are not greater than with standard cardiac transplantation, and (4) that the frequency of rejection episodes is highest within the first 60 days after transplantation.

Adult↗