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Biomedical subjects

D B Doty

Publications and source records attributed to D B Doty.

At least 37 records · Page 2Linked to original sources
PubMed1996

Pulsatile augmentation device for extracorporeal circulation.

A device has been designed, constructed, and tested to provide pulsatile pressure/flow to a standard extracorporeal bypass circuit. The pulsatile augmentation device is pneumatically driven similar to an artificial heart ventricle except that there are no valves. It is constructed of polyurethane by vacuum forming and high frequency welding. Drivers used are a modified Arrow-Kontron intraaortic balloon pump or the Utah artificial heart driver. In vitro testing with fresh bovine blood demonstrated acceptable blood compatibility and hemodynamic function. In vivo testing for 4 h in a right and left heart extracorporeal bypass circuit showed good pulse augmentation in pulmonary and systemic bypass circuits. The device shows promise for adding pulse to standard cardiopulmonary bypass and to extracorporeal right heart circulatory assist circuits.

Animals↗
PubMed1996

Aortic valve replacement with homograft and autograft.

The aortic valve may be replaced with an aortic homograft or a pulmonary autograft in children and young adults. The risk of surgery is low (2.5%). No anticoagulants are required, and thromboembolism is virtually unknown unless valve degeneration or endocarditis occur. Late follow-up indicates that approximately 85% of patients will be free of reoperation at 10 years when an aortic homograft is used and at 20 years when a pulmonary autograft is used.

Adult↗
PubMed1996

Improved long-term survival after heart transplantation predicted by successful early withdrawal from maintenance corticosteroid therapy.

BACKGROUND: Short-term studies suggest that cardiac transplant immunosuppression without maintenance corticosteroids is feasible in selected patients. However, concern exists as to the long-term effects, specifically the possibility of increased morbidity and mortality because of late allograft rejection and allograft coronary artery disease. METHODS: We retrospectively reviewed the records from 441 consecutive heart transplantation procedures done in 416 patients with use of an immunosuppressive protocol that attempted corticosteroid withdrawal within 2 months of transplantation. forty-two patients died or underwent retransplantation during the first 3 months and were excluded from further analysis. Analysis focused on demographic and long-term outcome variables (including death, rejection, retransplantation, and infection). RESULTS: Thirty percent (111) of eligible patients (374) met the definition of successful early steroid withdrawal. Only male gender independently predicted successful withdrawal. Mortality, both short and long term, was significantly lower in patients in whom successful early withdrawal from corticosteroids was achieved than in patients in whom the early attempts failed (1.7% per year versus 4.7% per year; p < 0.0001). The prevalence of late acute allograft rejection (more than 1 year after transplantation) was lower in patients successfully withdrawn from steroid therapy early after transplantation (0.07 pt-yr of follow-up versus 0.15 pt-yr; p = 0.002). Multivariate analysis of the entire group identified incidence of infection (p = 0.001), older age (p = 0.001), failed early steroid withdrawal (p = 0.006), and female gender (p = 0.016) as independent predictors of mortality. CONCLUSIONS: Successful early corticosteroid withdrawal identifies a subgroup of "immunologically privileged" patients with a low risk for long-term mortality and is not associated with an increased prevalence of late rejection or clinically significant coronary artery disease.

Case-Control Studies↗
PubMed1995

Long-term follow-up of extended aortoplasty for supravalvular aortic stenosis.

Extended aortoplasty is an operation that was designed to provide a symmetric reconstruction of the aortic root in patients with supravalvular aortic stenosis. The aim of this report is to provide long-term follow-up of the original cohort of 15 patients who underwent extended aortoplasty between 1975 and 1983. Follow-up was obtained in 14 patients. One patient was lost to follow-up 3 years after operation; he was included in this report. An echocardiogram, chest radiograph, and electrocardiogram were obtained for each surviving patient. The median length of follow-up was 141 months (range 36 to 238). The median preoperative gradient was 90 mm Hg (range 55 to 150). The median immediate postoperative gradient was 20 mm Hg (range 0 to 50, p < 0.05 compared with preoperative gradient) and the median long-term gradient was 32 mm Hg (range 6 to 96, p < 0.05 compared with preoperative gradient; p = not significant compared with immediate postoperative gradient). Two patients died: one of left ventricular failure after a subsequent aortic valve replacement and one of chronic left ventricular failure. The Kaplan-Meier estimate of survival at 218 months for all patients was 77.4% (70% confidence limits 62% to 93%). The estimated freedom from reoperation for all patients was 69% at 218 months (70% confidence limits 56% to 82%). Univariate analysis revealed that the presence of a bicuspid valve is a significant risk factor for reoperation (p = 0.038), but not for death (p = 0.51). The Kaplan-Meier estimate of freedom from reoperation for patients with a bicuspid aortic valve was 42.9% at 141 months (70% confidence limits 21% to 65%). Extended aortoplasty provides effective long-term relief of the pressure gradient across the supravalvular ridge. However, a significant number of patients require subsequent operations, particularly those with a bicuspid aortic valve.

Adolescent↗
PubMed1994

Early and intermediate results of the Fontan procedure at moderately high altitude.

At higher elevations, alveolar hypoxia increases pulmonary vascular resistance and may limit the cardiac output of individuals without a subpulmonary ventricle. Thus, we reviewed the outcome of definitive palliation for tricuspid atresia and other forms of single ventricle in 60 consecutive Fontan patients living at a mean elevation of 1,370 m (range, 910 to 2,130 m). There were four early deaths (6.7%; 70% confidence limits, 4.1% to 10.7%) and six late deaths. Kaplan-Meier actuarial survival (+/- standard error) is 79.6% +/- 8.2% at 5 years. Survival was significantly decreased in patients with a preoperative mean pulmonary arterial pressure greater than or equal to 15 mm Hg unless the Fontan procedure was performed with a residual fenestration. Exercise tolerance was significantly worse at higher elevations in a subgroup of patients who have traveled to altitudes of 1,680 to 3,350 m. We conclude that the early and intermediate results of the Fontan procedure at moderately high altitude are similar to results reported at sea level. However, exercise tolerance may be impaired at higher elevations in many patients.

Adolescent↗
PubMed1994

Hypothermic circulatory arrest for cardiac valve replacement reoperations.

Three patients had cardiac valve replacement using hypothermic circulatory arrest. The patients had multiple previous operations via median sternotomy, and 1 had functioning coronary bypass grafts. This technique provided simple and safe reentry to the heart without necessity of control of the aorta or venae cavae, adequate myocardial and cerebral protection from ischemia, and excellent operating conditions for the valve replacement.

Adult↗
PubMed1994

Aortic valve prosthesis obstruction after aortoventriculoplasty: reconstruction with aortic allograft.

An aortoventriculoplasty (Konno procedure) operation was performed for relief of tunnel-type subaortic stenosis using a Bjork-Shiley valve aortic prosthesis. The mechanical prosthesis thrombosed and cerebral embolism occurred when anticoagulant medication was stopped. The aortic root was successfully reconstructed with a cryopreserved aortic allograft using freehand implant technique. The cryopreserved aortic allograft is an excellent replacement device in the young adult patient in cases of failed prostheses, even in the presence of complex left ventricular outflow tract morphology or previous reconstruction operations.

Adult↗
PubMed1994

Replacement of the aortic valve with cryopreserved aortic allograft: the procedure of choice for young patients.

The results of replacement of the aortic valve with cryopreserved aortic allograft are reviewed. There were no operative deaths in 88 patients. Thromboembolism did not occur in any patient and no anticoagulant medications were used. Actuarial freedom from reoperation for any reason was 89%; for structural deterioration it was 93% at 7.5 years. Infection was cured in all patients with endocarditis. Aortic allografts may be inserted by: (1) 120 degrees rotation freehand technique; (2) intact noncoronary sinus freehand technique; (3) aortic root enlargement technique; and (4) aortic root replacement technique. Zero thromboembolism without anticoagulants, high rate of cure of endocarditis, and the versatility of the tissue with a variety of methods for insertion to rebuild and remodel the aortic root to provide normal hemodynamic characteristics make aortic allograft the device of choice for replacement of the aortic valve in young patients.

Adult↗
PubMed1993

Replacement of the aortic valve with cryopreserved aortic allograft.

Replacement of the aortic valve with cryopreserved aortic allograft was performed in 88 patients during the period from July 1985 until January 1993. Age of patients ranged from 15 to 75 years (mean, 44 years). The cause of aortic valve disease was congenital in 39 (44%), rheumatic in 9 (10%), degenerative in 14 (16%), endocarditis in 11 (13%), and failed prosthesis in 15 (17%). The operation was performed by freehand allograft technique in 71 patients (81%). There were no perioperative deaths. Two patients died later at 4 months and 5 years after operation (actuarial survival = 94% at 7.5 years). Follow-up extending to 7.5 years shows 87% of patients are in New York Heart Association functional class I. No thromboembolism has been detected in any patient. Infection was cured in all patients with endocarditis. Mild aortic valve incompetence was detected by diastolic murmur in 45% of patients. Only three valves have been removed at reoperation: one was removed early for technical reasons, and two valves were removed for structural degeneration at 33 and 55 months; the latter was infected. Actuarial freedom from reoperation for any reason was 89%; for structural deterioration it was 93% at 7.5 years. Aortic valve replacement with cryopreserved aortic allograft can be safely performed in adult patients. Medium-term results show excellent freedom from thromboembolism and cure of bacterial endocarditis. Mild aortic valve incompetence is often present, but reoperation for progressive incompetence is unusual.

Actuarial Analysis↗
PubMed1993

Aortic valve replacement and mitral valve repair with allograft.

Techniques of repair of defects in the anterior leaflet of the mitral valve and replacement of the aortic valve using allograft are presented. The case history and operative procedure of a reconstructive operation that did not require anticoagulant therapy after surgery are described for three adult patients. Mitral valve defects were repaired using the anterior leaflet of the mitral valve of the allograft. The aortic valve or entire root was replaced with the aortic allograft. The aortic/mitral allograft should be considered as an alternative to replacement of the aortic and mitral valves with prostheses in selected patients.

Adult↗
PubMed1993

Aneurysm of the left atrium.

A case of aneurysm of the body of the left atrium is reported. Diagnosis of this condition should be considered in patients presenting with supraventricular tachyarrhythmia and a mass on the left side of the heart. Surgery to remove the aneurysm is the treatment of choice.

Adult↗
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

The surgeon's response to a low-output state after cardiopulmonary bypass: etiologies and remedies.

Following cardiopulmonary bypass, a series of steps can usually be used to restore function to the heart. A low postbypass cardiac output can be countered with a response checklist that includes adjusting heart rate, correcting cardiac arrhythmia, ensuring adequate hematocrit, adjusting preload and afterload, and stimulating cardiac contractility. It is the surgeon's responsibility to make a thorough investigation of any structural abnormality that may contribute to the low-output state; adequate repair of cardiac defects will often result in an improved hemodynamic state. Hemorrhage is an important cause of poor cardiac performance. Tamponade of the heart is usually due to retained clots associated with hemorrhage after operation and is indicated by a low-output state with equalization and elevation of atrial pressures. In a low-output, postsurgical state, the possibility of residual shunts and obstructions, inadequate valve repair, and closure or inadequate flow through a graft may need to be investigated. Once that has been achieved, the appropriate steps can be taken to improve cardiac performance.

Arrhythmias, Cardiac↗
PubMed1990

Cardiac transplantation in situs inversus.

Transplantation of the heart was successfully performed in a patient with situs inversus of the viscera and atria. Anatomic constants common to all patients allowed the left atrium, pulmonary artery, and aorta to be joined as usual in the transplant operation. Systemic venous reconstruction was the crux of the operation. A composite superior vena cava was reconstructed on the right side from the recipient translocated superior vena cava, donor superior vena cava and innominate vein, and recipient in situ pericardium. The inferior vena cava was rerouted from the left side across the midline to the right through a composite conduit consisting of the recipient night atrium and in situ pericardium over the diaphragm. These reconstructed venous passageways have remained patent and unobstructed for 1 1/2 years after the operation.

Anastomosis, Surgical↗
PubMed1990

Bypass of superior vena cava. Fifteen years' experience with spiral vein graft for obstruction of superior vena cava caused by benign disease.

Nine patients had operations for obstruction of the superior vena cava with superior vena caval syndrome caused by benign disease. Three patients had fibrosing mediastinitis, four had fibrosing mediastinitis with caseous necrosis, one had thrombosis of the superior vena cava around a pacemaker electrode, and one had spontaneous thrombosis of the superior vena cava. Patients ranged in age from 25 to 68 years. All bypass operations were performed with a composite spiral vein graft constructed from the patient's own saphenous vein, split longitudinally and wrapped around a stent in spiral fashion. The edges of the vein were sutured together to form a large conduit ranging in diameter from 9.5 to 15.0 mm. Six grafts were from the left innominate vein and three grafts were from the internal jugular vein. The grafts were placed into the right atrial appendage in all except one case, in which the graft was to the distal superior vena cava. Follow-up extends from 1 to 15 years. One patient required reoperation at 4 days for thrombosis at the innominate vein-graft anastomosis. Resection of the anastomosis and reconstruction of the graft rendered the patient symptom free. Two grafts closed during the first year after operation. One patient had advancing fibrosing mediastinitis, and a second bypass graft from the external jugular veins remain patent. Another patient had recurrence of spontaneous venous thrombosis. Thus seven of nine grafts remain patent for up to nearly 15 years and all but one patient is free of superior vena caval syndrome. These data show that bypass of the obstructed superior vena cava with a spiral vein graft relieves superior vena caval syndrome and demonstrate long-term patency of the graft.

Adult↗
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↗