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Biomedical subjects

V A Starnes

Publications and source records attributed to V A Starnes.

At least 109 records · Page 6Linked to original sources
PubMed1991

Effects of pulmonary restriction on hypercapnic responses of heart-lung transplant recipients.

Previous studies of hypercapnic ventilatory responses (HCVR) in human heart-lung transplant recipients (HLTX) have yielded conflicting results. We compared the HCVR of restricted transplant recipients (HLTX-R) to recipients with normal pulmonary function (HLTX-N), and normal controls (C). HLTX-R exhibited limited tidal volume responses, whereas their frequency responses were essentially identical to those of other subjects. Accordingly, HCVR of HLTX-R (1.45 +/- 0.59 l.min-1.Torr CO2(-1)) were significantly depressed compared with both HLTX-N and C (2.90 +/- 0.55 vs 3.05 +/- 1.23, respectively) (P less than 0.02). Despite undoubtedly greater ventilatory impedances, airway (mouth) occlusion pressure responses (Pm0.1) during hypercarbia of HLTX-R (0.46 +/- 0.28 cmH2O) were similar to those of C (0.43 +/- 0.20) and paradoxically blunted compared with HLTX-N (0.83 +/- 0.36) (P less than 0.02). We conclude that pulmonary reflexes are superfluous for maintenance of HCVR in HLTX with normal respiratory mechanics, whereas the presence of moderate restriction results in profound depression of CO2 responses among these subjects.

Adult↗
PubMed1991

Hypercarbic ventilatory responses of human heart-lung transplant recipients.

To evaluate the effects of chronic pulmonary denervation on ventilatory control, we compared the hypercarbic ventilatory responses (HCVR) of 12 human heart-lung transplant recipients (HL) and 24 normal control subjects (C). The six male HL were subsequently compared with eight male heart transplant recipients (H), as well as the 12 male C. All subjects had normal spirometry, but lung volumes of both transplant groups were somewhat less than those of C. The HCVR of HL and C were indistinguishable (2.68 +/- 0.28 versus 2.71 +/- 0.22 L/min/mm Hg, respectively). The increment of mouth occlusion pressure (delta Pm0.1/delta CO2), however, was markedly greater in HL (P much less than 0.01). The three male groups also had equivalent HCVR, and again, the HL had an increased delta Pm0.1/delta CO2. HL men exhibited larger increments of VT and decreased frequency responses during CO2 rebreathing than did male C and H, although these differences were statistically significant only in the comparison between the transplant groups. We conclude that HL with normal spirometry have appropriate HCVR, despite pulmonary denervation. Pm0.1 responses of these subjects are increased, however, reflecting either a compensatory response to greater respiratory impedances or an occult alteration of ventilatory mechanics. Moreover, compared with subjects with similar pulmonary function, e.g., heart transplant recipients, the breathing pattern of HL during progressive hypercarbia is consistent with the absence of vagal-mediated inflation inhibition.

Adult↗
PubMed1991

Present status of heart transplantation.

Heart transplantation has evolved from an experimental procedure with a low survival rate to a therapeutic option for patients with end-stage heart disease. The most common diagnosis among recipients is cardiomyopathy, followed by coronary artery disease and vascular disease. As immunosuppression techniques have improved and protocols standardised heart transplantation has been successfully employed by many centres. A growing insight into the risks and benefits of cardiac transplantation means that we can stratify an individual patient's risk, thereby enhancing both selection for and timing of transplantation. The number of suitable donors available is limited so we should ensure that donor's hearts go those patients who stand to gain the greatest benefit after operation. The cost-benefit ratio has been shown to be good and heart transplantation is nowadays a routine procedure in cardiac surgery.

Costs and Cost Analysis↗
PubMed1991

Pediatric heart transplantation at Stanford: results of a 15-year experience.

The long-term results of pediatric heart transplantation were evaluated in 53 patients, aged 0.25 to 18.94 years, who received transplants at Stanford University Medical Center between 1974 and 1989. Indications for transplantation were idiopathic cardiomyopathy (68%), congenital heart disease (21%), endocardial fibroelastosis (8%), and doxorubicin cardiomyopathy (3%). Immunosuppression was achieved with combinations of cyclosporine, prednisone, and azathioprine. Thirty-seven of 42 recipients leaving the hospital after transplantation were alive and in New York Heart Association class I at study's end. Cumulative survival was 79% at 1 year, 76% at 3 years, and 69% at 5 years. Fourteen recipients have survived more than 5 years (5.1 to 12.4 years). Hospital readmission for illness has been infrequent, decreasing from 6.8 days to 0.9 days per year over 5 years. Eleven patients have required no rehospitalization. Posttransplant deaths were due to infection (19%), rejection (4%), pulmonary hypertension (4%), coronary artery disease (2%), and lymphoproliferative disease (2%). Retransplantation was required for intractable rejection in 4 patients and advanced coronary artery disease in 2. Hypertension and elevated blood urea nitrogen and creatinine levels were common in individuals receiving cyclosporine. Growth was often impaired in prepubertal children receiving daily prednisone. Based on this 15-year experience, it is concluded that heart transplantation represents a reasonable alternative for selected young patients with end-stage cardiac disease.

Adolescent↗
PubMed1991

Clinical experience with the Novacor ventricular assist system. Bridge to transplantation and the transition to permanent application.

At Stanford University, a Novacor left ventricular assist system (Baxter Healthcare Corporation, Novacor Division, Oakland, Calif.) was placed as a bridge to heart transplantation in 13 patients. During the hospitalization preceding device implantation, all patients were receiving inotropic support for biventricular failure, 11 had pulmonary edema, 6 had life-threatening ventricular arrhythmias, 5 had liver dysfunction with coagulopathy, and 2 had renal failure necessitating artificial support. The mean cardiac index before implantation of the Novacor system was 1.5. All survivors with the Novacor device had a dramatic increase in cardiac output (mean cardiac index = 3.1). One patient with cardiac allograft rejection died during implantation of the left ventricular assist system. Two patients died of pulmonary sepsis and multiorgan failure after the device was implanted. All patients who had the Novacor device implanted for more than 7 days were able to walk and ride stationary bicycles while awaiting transplantation. Ten patients (77%) underwent successful heart transplantation after a mean of 18 days' support with the Novacor device. One patient died of presumed sepsis 2 days after transplantation. Nine patients (90%) are alive 4 months to 6 years after transplantation. In the overall United States experience, 68 patients (as of May 1990) have had a Novacor left ventricular assist device implanted. Five were still being supported, 39 had received a transplant (62%), and 35 patients (90%) survived the transplant hospitalization (1 died later). No instances of device failure have occurred. Overall, the Novacor assist system provided effective bridging to transplantation, with posttransplant survival similar to results after routine transplantation. Modifications and improvements based on this clinical experience have been made in the areas of patient selection, techniques of operative placement, postoperative management, and design of the assist system. Isolated left heart support with a fully implantable left ventricular assist system will be offered as an alternative to heart transplantation for selected patients by 1992.

Adolescent↗
PubMed1991

Ebstein's anomaly appearing in the neonate. A new surgical approach.

Ebstein's anomaly appearing during the neonatal period carries a high mortality rate. These infants exhibit cyanosis, acidosis, and congestive heart failure. The pathophysiologic characteristics consist of severe tricuspid regurgitation and functional pulmonary atresia. As a result of the inability of the right ventricle to generate forward flow through the pulmonary arteries, these infants remain dependent on ductal patency. Since May 1988, five newborn infants with severe Ebstein's anomaly have been admitted for treatment at our institution. At initial examination, they weighed 3.6 +/- 1.8 kg and had a mean oxygen tension of 29.6 +/- 2.3 mm Hg and a mean pH of 7.20 +/- 0.05. Chest roentgenography demonstrated a mean cardiothoracic ratio of 0.81 +/- 0.02. As determined by echocardiography, the right atria were massively enlarged, severe tricuspid regurgitation was present in all patients, and the pulmonary valves were not opening. All infants were dependent on prostaglandin E1 and attempts to wean them from this drug were unsuccessful. Palliative treatment consisted of tricuspid closure with autologous pericardium and an aortopulmonary shunt of 4 mm polytetrafluoroethylene tubing. There were no operative or late deaths. At discharge, mean oxygen tension was 42.2 +/- 0.85 mm Hg and mean systemic oxygen saturation was 83.2% +/- 1.94%. Infants have grown satisfactorily during the follow-up period. Three infants have since returned for further surgical intervention. One infant, at 11 months of age, underwent a Glenn anastomosis for progressive oxygen desaturation. Two infants have returned, at ages 23 and 22 months, for Fontan procedures, which represent their definitive operative management. We believe this new procedure offers excellent palliative treatment for Ebstein's anomaly in critically ill neonates. Feasibility of later definitive correction is demonstrated by the good results obtained with the Fontan procedure in two infants.

Ebstein Anomaly↗
PubMed1990

Induction of donor-specific unresponsiveness to cardiac allografts in rats by pretransplant anti-CD4 monoclonal antibody therapy.

In the present report a monoclonal antibody designated OX-38 directed against the rat CD4 molecule was tested for its ability to prolong the survival of heterotopic vascularized rat heart allografts transplanted across major histocompatibility barriers. Fluorescence-activated cell-sorter analysis showed that administration of OX-38 selectively depleted 80-95% of CD4+ cells from peripheral blood of treated rats. The immunosuppressive effects of OX-38 in vivo were verified by suppression of an antibody response against OX-38 itself as a heterologous protein immunogen. Recipient rats received OX-38 antibody as a single agent given in pretransplant regimens. Nine of 12 treated rats have maintained heterotopic abdominal heart allografts for greater than 175 days. Control rats that did not receive antibody therapy rejected their grafts within 14 days. Rats that maintained heart allografts for greater than 100 days accepted second donor strain hearts but rejected third-party heart grafts transplanted into the femoral space. Anti-CD4-induced allograft unresponsiveness persisted for at least 90 days following surgical removal of donor tissue and retransplantation of a second donor-matched heart. These results indicated that transient, pretransplant therapy with monoclonal antibodies directed against the CD4+ lymphocyte induced specific, long-lasting unresponsiveness to fully MHC-mismatched cardiac allografts in rats without additional immunosuppression.

Animals↗
PubMed1990

Selection and evaluation of recipients for heart-lung and lung transplantation.

Heart-lung and lung transplantation is being successfully performed with increasing frequency in patients with end-stage cardiopulmonary and pulmonary disease. Transplantation must now be considered as a therapeutic option in selected patients, and physicians are required to understand the principles involved for determining suitable candidates and operative procedures of choice. Indications, contraindications, and choice of operation with respect to underlying disease are discussed herein, as are methods of evaluation and appropriate timing for transplantation. Special considerations regarding specific patient populations are also addressed. In properly selected patients, heart-lung and lung transplantation provide a viable therapeutic option in those with end-stage disease who are unresponsive to conventional management.

Contraindications↗
PubMed1990

Acute lung rejection after heart-lung transplantation: correlation of findings on chest radiographs with lung biopsy results.

This retrospective study was performed to determine if the chest radiograph could serve as a predictor for acute lung rejection in heart-lung transplantation patients. The findings on chest radiographs were correlated with the results of transbronchial biopsies in 16 heart-lung transplantation patients. The chest radiographs immediately preceding 83 biopsies were evaluated for a variety of findings. The histopathologic results of the lung biopsies were divided into five categories: (1) acute lung rejection (n = 25); (2) suggestive, but not diagnostic, of acute lung rejection (n = 8); (3) nonspecific (n = 26); (4) infection (n = 17); and (5) normal lung (n = 9). Biopsies from two patients showed both acute lung rejection and cytomegalovirus infection and were included in both categories. These histopathologic results were then correlated with the radiologic observations. We found that the combination of septal lines and new or increasing pleural effusions, without concomitant increase in cardiac size or vascular pedicle width, or evidence of vascular redistribution, indicated acute lung rejection with a sensitivity of 68% (17/25), specificity of 90% (52/58), and overall accuracy of 83% (69/83). We conclude that the chest radiograph is a useful indicator of acute lung rejection.

Adult↗
PubMed1990

Obliterative bronchiolitis.

The mass of evidence suggests that OB is a manifestation of allograft rejection in the time period later than that usually associated with acute postoperative rejection. Respiratory infection may serve to amplify (and possibly trigger) this process. A maintenance immunosuppression regimen utilizing cyclosporine A, prednisone, and azathioprine appears to be much more effective than an earlier regimen utilizing only the first two drugs. Aggressive surveillance utilizing prospective measurement of pulmonary function and arterial blood gases and a willingness to look for histologic evidence of OB with the earliest symptomatology has lowered significantly the mortality and the morbidity of this disorder at Stanford and elsewhere. We believe that the current ability to treat and even reverse this serious complication brightens the prospect of heart-lung and lung transplantation for assuming a role in the medical practice of the future.

Adult↗
PubMed1990

Pediatric heart transplantation.

Heart transplantation has been performed successfully in the pediatric age group for just over 10 years, yet early results are encouraging, and this procedure has moved from the realm of experimental therapy to that of accepted medical practice for certain specific conditions. In infants and children with cardiomyopathies or with congenital heart disease for which no reasonable standard surgical alternative exists, heart transplantation offers the best hope for long-term survival. Most important, in those patients surviving heart transplantation, rehabilitation has been almost universally complete. Although the long-term prospects for pediatric heart transplant patients are still unknown, we have now accumulated sufficient experience in adults suggesting the potential for decades-long survival. Future improvements in diagnosis and treatment of rejection and prevention of the complications of immunosuppressive therapy will continue to improve the prospects for lifelong survival in these patients.

Adolescent↗
PubMed1990

Improved survival after heart-lung transplantation.

Sixty-two patients underwent 65 heart-lung transplant operations before April 1989. Thirty of these patients (operated on March 1981 to February 1986) were given cyclosporine and prednisone for immunosuppression. These 30 patients (group 1) are compared with the 32 most recent patients (group 2) treated with cyclosporine, prednisone, and azathioprine. Patient characteristics (group 1 versus group 2) were similar including age (mean 32 versus 26 years) and indication for operation (51% versus 38%, primary pulmonary hypertension; 46% versus 45%, Eisenmenger complex; 3% versus 17%, other). The perioperative (in-hospital) mortality rate was 35% in group 1 versus 16% in group 2. Obliterative bronchiolitis developed in 12 (63%) of 19 hospital survivors in group 1 from 2 months to 49 months postoperatively (mean 12 months). This complication has developed in five (20%) of the 25 hospital survivors in group 2 from 3 to 13 months postoperatively (mean 8 months). Overall, 24 of the 30 patients in group 1 died (infection in eight, obliterative bronchiolitis in five, graft coronary artery disease in two, other causes in nine). Eight of the 32 patients in group 2 died (infection in six, other cases in two). Survival rates for group 1 patients were 60% at 1 year, 50% at 2 years, 43% at 3 years, and 25% at 5 years. Survival rates for group 2 patients were 73% at 1 year, 73% at 2 years, and 65% at 3 years (p less than 0.05). When group 2 patients were compared with 134 patients undergoing heart transplantation during the same time period, there was no difference in survival. Routine bronchoscopic surveillance in the more recent group of patients has led to the earlier detection of rejection and infection. In combination with decreased perioperative mortality and augmented immunosuppression, this had led to improved survival in our more recent heart-lung transplant recipients. In addition, the earlier recognition of infection and rejection has led to a decrease in severity of obliterative bronchiolitis.

Adult↗
PubMed1990

Eight-year results of cyclosporine-treated patients with cardiac transplants.

To elucidate the long-term effects of cyclosporine, we retrospectively studied 310 consecutive patients who have undergone cardiac transplantation at our institution since December 1980 and in whom immunosuppression has been maintained with cyclosporine. The ages of recipients ranged from 1 month to 64 years and of donors from 1 month to 48 years. The actuarial survival rates for cyclosporine-treated patients were 80.7% at 1 year and 59.7% at 5 years and were significantly greater than those for previous patients not treated with cyclosporine (p less than 0.005). Their actuarial prevalence of rejection was 60.0% at 1 month and 86.9% at 1 year; 206 patients are living. The actuarial prevalence of lymphoma development was 4.6% at 5 years but has been significantly lower with the current immunosuppression protocol of lower doses of cyclosporine, and OKT3 in place of rabbit anti-thymocyte globulin (p less than 0.005). Infection remains the most common cause of death. Recipients less than 50 years of age had a significantly higher actuarial survival than older recipients (p less than 0.01). Male and female recipients had similar overall prevalence of survival and rejection, but men died of graft atherosclerosis significantly more frequently (p less than 0.005). Rehabilitation has been successful in 85% of patients surviving 1 year after transplantation. Of those surviving 1 year, 96.5% were in New York Heart Association class I. Thus the results of orthotopic cardiac transplantation have improved since the introduction of cyclosporine and have allowed measured liberalization of the criteria for recipient selection.

Adolescent↗