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Biomedical subjects

P E Oyer

Publications and source records attributed to P E Oyer.

At least 19 recordsLinked to original sources
PubMed1992

Heart, heart-lung, and lung transplantation in the first year of life.

Seventeen infants less than 1 year of age have undergone heart (12), heart-lung (3), and lung (2) transplantation for end-stage cardiopulmonary disease. The infants undergoing heart transplantation had a mean age of 4.5 months (range, 19 days to 12 months) with the diagnosis of cardiomyopathy in 4 and congenital heart disease in 8. Four of the 8 patients (50%) had hypoplastic left heart syndrome. Actuarial survival at 1 and 2 years was 74% and compared favorably with the survival of older children at 1 and 2 years of 82% and 69%. The linearized rejection rate was less in infants as compared with children more than 1 year of age (0.61 versus 1.48 episodes per 100 patient days). In intermediate follow-up, no graft atherosclerosis has been noted. Immunosuppression has included a three-drug protocol of cyclosporine, azathioprine, and prednisone. A steroid taper to alternate day steroids or off completely by 6 months has been the goal and has been accomplished in 6 of 12 infants. Heart-lung and lung transplantation has been performed in 5 infants. One infant in each group died: 1 infant secondary to airway complications and sepsis and another due to pulmonary sepsis. A pulmonary lobe from a larger and older donor was transplanted into a 4-week-old infant as a single-lung transplant with good outcome. The 3 surviving infants are well 24, 18, and 2 months after transplantation. Obliterative bronchiolitis has not been clinically apparent in this group. These data support the clinical efficacy of heart, heart-lung, and lung transplantation in the first year of life.

Actuarial Analysis↗
PubMed1992

Cystic fibrosis. Target population for lung transplantation in North America in the 1990s.

Cystic fibrosis is the most common lethal genetic disease occurring in the white population. It is estimated that 3.5% of the 20,000 individuals with cystic fibrosis in North America will die each year of end-stage lung disease. Lung transplantation (heart-lung or double lung) is becoming more frequent as more patients are referred for this procedure. Since January 1988, we have evaluated 60 patients with cystic fibrosis for lung transplantation and have accepted 30 (50%). Nine patients (30%) died while awaiting a donor. Fifteen patients underwent transplantation (13 heart-lung and two double lung procedures). Actuarial survival at 1, 2, and 3 years is 76%. All survivors are without physical limitations. Pulmonary function, as determined by forced vital capacity, forced expiratory volume in 1 second, and arterial blood gas determinations, is within the normal range. Comparing these data with those of a group of patients without cystic fibrosis who underwent transplantation during the same period did not reveal any significant differences with respect to infection, rejection, and outcome. Preliminary data suggest that obliterative bronchiolitis is less prevalent at 1 year in patients with cystic fibrosis (19%) than in those without cystic fibrosis (41%). Patients with cystic fibrosis present a number of challenges. The problems of pleural adhesions from repeated infections, pleurodesis, and previous thoracic procedures are now readily approached through the bilateral thoracosternotomy (clam shell) incision. Insulin-dependent diabetes mellitus and low-dose corticosteroid therapy are no longer considered absolute contraindications. Both septic lungs must be removed at operation, either with heart-lung transplantation or with double lung transplantation. These data support the therapeutic efficacy of lung transplantation for patients with cystic fibrosis.

Actuarial Analysis↗
PubMed1992

Durability of porcine valves at fifteen years in a representative North American patient population.

Isolated aortic (n = 857) or mitral (n = 793) valve replacement with a porcine bioprosthesis was performed in 1650 patients between 1971 and 1980. Follow-up (total = 12,012 patient-years) extended to more than 15 years and was 96% complete. Patient age ranged from 16 to 87 years; mean age was 59 +/- 11 years (+/- 1 standard deviation) for the aortic valve replacement cohort and 56 +/- 12 years for the mitral valve replacement cohort. The operative mortality rates were 5% +/- 1% (+/- 70% confidence limits) and 8% +/- 1%, respectively, for the aortic and mitral subgroups. Estimated freedom from structural valve deterioration (+/- 1 standard error of the mean) after 10 and 15 years was significantly higher for the aortic than for the mitral valve replacement subgroup (85% +/- 0.4% and 63% +/- 3% versus 78% +/- 2% and 45% +/- 3%, respectively, p = 0.001). Reoperation-free actuarial estimates were also significantly greater for the aortic valve replacement cohort: 83% +/- 2% and 57% +/- 3% versus 78% +/- 2% and 43% +/- 3% for mitral valve replacement at 10 and 15 years, respectively. The mortality rate for reoperative aortic valve replacement was 11% +/- 1%; it was 8% +/- 1% for reoperative mitral valve replacement. Importantly, the estimates of freedom from valve-related death (including sudden, unexplained deaths) were relatively high at 10 and 15 years: 78% +/- 2% and 69% +/- 3% in the aortic cohort and 74% +/- 2% and 63% +/- 3% in the mitral cohort (p = not significant). Excluding sudden, unexplained deaths, these estimates were 81% +/- 3% (aortic) and 73% +/- 4% (mitral) at 15 years. Thromboembolism-free rates were 84% +/- 3% (aortic) and 78% +/- 6% (mitral) at 15 years, and freedom from anticoagulant-related hemorrhage was 96% +/- 1% and 89% +/- 2%, respectively. At the time of current follow-up, 13% of patients having aortic valve replacement and 50% of patients having mitral valve replacement were receiving warfarin sodium. The hazard functions for thromboembolism and prosthetic valve endocarditis were constant and remained less than 1%/pt-yr over the entire follow-up period.(ABSTRACT TRUNCATED AT 400 WORDS)

Actuarial Analysis↗
PubMed1979

Aortic and mitral prosthetic valve reoperations: early and late results.

A total of 232 valvular reoperations (123 mitral valve reoperations [RMVR] and 109 aortic valve reoperations [RAVR] were performed in 194 patients with previously implanted prosthetic valves. Early mortality was 10% (12/123) for the RMVR subgroup and 14% (15/109) for the RAVR subgroup (P = NS). Late mortality was 16% (18/111) for the RMVR subgroup and 25% (23/94) for the RAVR subgroup (P = NS). Patients with prosthetic endocarditis or prosthetic stenosis constituted higher-risk subpopulations. Principal determinants of both operative mortality and late attrition were preoperative cardiac functional status and the nature of the pathology mandating valve replacement. Early prosthetic valve replacement is advocated to correct hemodynamic abnormalities before advanced ventricular decompensation ensues, especially when prosthetic valvular endocarditis or prosthetic stenosis exists.

Aortic Valve↗
PubMed1979

Late right heart reconstruction following repair of tetralogy of Fallot.

Twenty-two symptomatic patients underwent a total of 28 reoperative procedures after initial surgical repair of tetralogy of Fallot. Sixteen of the patients were considered to have unfavorable anatomy of the right ventricular outflow tract (RVOT) or pulmonary artery at the time of initial repair. Pulmonary or tricuspid valve replacement, or replacement of both valves, utilizing a xenograft bioprosthesis was performed in 1 of the 22 initial repairs, 7 of the 22 first reoperations, and 5 of the 6 second reoperations. Ultimately, 14 patients received transannular RVOT patches. The interval between the first and second reoperations for 6 patients who required 2 late reconstructive procedures was 5.8 years. No operative deaths occurred. There were 2 late deaths (1 sudden and 1 due to aspiration). Actuarial survival probability (+/- standard error of the mean) 16 years after initial repair was 72 +/- 21%. Eighteen of the 20 current survivors in the present series are completely asymptomatic without physical restrictions; the other 2 are considered to be in New York Heart Association Functional Class II. No xenograft bioprosthetic dysfunction has occurred to date, but cumulative valve follow-up is limited (13 patient-years). In selected patients, earlier pulmonary or tricuspid valve replacement or replacement of both of these valves can provide some degree of protection against recurrent deterioration.

Adolescent↗
PubMed1979

Current management of cardiac transplant recipients.

Changes in the management of cardiac transplant recipients over the past 10 years have resulted in a substantial improvement in the outlook for survival. Imuran and prednisone remain the primary immunosuppressive agents, but rabbit antihuman thymocyte globulin is used initially and reinstituted during rejection. Endomyocardial biopsy has allowed more precise diagnosis and management of rejection, and more recently immunological monitoring has been introduced to provide more frequent assessment of the host immune response. Infection is the major cause of death, and its diagnosis and treatment is managed aggressively. Current survival figures justify the use of cardiac transplantation, by an experienced team, when other measures have been exhausted.

Adolescent↗
PubMed1979

Left ventricular aneurysm. Preoperative risk factors and long-term postoperative results.

The results of operative treatment of postinfarction left ventricular aneurysm in 169 patients undergoing operation since 1970 are analyzed in this report. Maximum follow-up extended to 7 year (average 2.9 years). Average patient age was 56 years (range 34 to 82 years). Nearly all patients (94%) had left anterior descending coronary artery disease with anterior aneurysm formation and 73% had multivessel disease. Sixty-eight percent of patients underwent aorta-coronary bypass grafting (ACBG) and/or mitral valve replacement (MVR) concomitantly with aneurysmectomy. The over-all operative mortality rate was 17.8%. Preoperative factors that correlated significantly (p less than 0.05) with increased operative risk reflected primarily the quality of left ventricular function, and included functional classification, cardiac index, contractile function of residual myocardium not involved by aneurysm, and mitral regurgitation. Patients whose primary preoperative disability consisted of angina pectoris (42 patients) exhibited significantly higher over-all survival rates (actuarial 5 year survival 75%) than those undergoing operation because of congestive heart failure (86 patients) or ventricular tachyarrhythmias (38 patients), whose 5 year survival rates were 52 and 57%, respectively. Concomitant ACBG (+/- MVR) was associated with a higher operative mortality rate than aneurysmectomy alone (21.1 versus 10.9%), but late postoperative attrition was similar. The over-all 5 year survival rate, including operative death, was 60%, and 90% of surviving patients were in Functional Class I or II at follow-up evaluation. We conclude from this analysis that the long-term prognosis of patients with symptomatic postinfection left ventricular aneurysms, although determined importantly by preoperative left ventricular function, is enhanced by surgical treatment.

Adult↗
PubMed1979

Distant heart procurement for transplantation.

Between January 1, 1977, and September 15, 1978, 39 cardiac transplants were performed on 38 patients. Twenty donor hearts were removed at Stanford University Hospital, and 19 donor hearts were removed at distant hospitals. The characteristics of recipients and donors in both groups were similar. The only significant difference between donor hearts was the mean ischemia time (154 +/- 30 minutes in distant hearts and 52 +/- 12 minutes in local hearts, P less than 0.001). As of February 1, 1979, the total mortality rate was 32% for the distant heart donors and 40% for the local heart donors. No difference between the two groups was present in immediate myocardial function, the need for postoperative inotropic support, the mortality rate within the first 90 days after operation, the mean maximum serum enzyme levels, the occurrence of rejection or infection, and the histological appearance of the hearts, both early and late. The results of cardiac transplantation when hearts are removed at distant hospitals are entirely comparable to the results with hearts removed on site with a minimum ishchemic time. Distant heart procurement provides an expanded donor pool for potential cardiac recipients.

Coronary Vessels↗
PubMed1979

Diagnosis and treatment of acute cardiac allograft rejection.

Integration of data derived from immunologic monitoring techniques and endomyocardial biopsy currently permits more precise administration of immunosuppressive medications for the treatment of acute cardiac allograft rejection than was formerly possible, resulting in a substantially improved outlook for long-term survival. Indeed, the probability of survival for 5 years postoperatively of 50% exceeds that for several categories of cardiac patients currently undergoing other more common forms of heart surgery. The continuing demonstration of the potential for cardiac transplantation clearly warrants further application of this procedure for the treatment of appropriate patients with end-stage cardiac disease.

Adrenal Cortex Hormones↗
PubMed1979

Surgical treatment of aneurysms of the inferior left ventricular wall.

Experience with surgical treatment of 10 patients with aneurysms of the inferior wall of the left ventricle is presented. Six of the 10 aneurysms were false (pseudoaneurysms), and four were classified as true aneurysms. All except one resulted from myocardial infarction. Combined procedures, performed at the time of aneurysm resection, included mitral valve replacement (five patients), coronary artery bypass grafting (four patients), and closure of an interventricular septal defect (one patient). Three of four patients with true inferior aneurysms had mitral valve dysfunction, whereas only two of six patients with false aneurysms required mitral valve replacement (one because of infective endocarditis). Nine of the 10 patients survived operation, and all are functionally improved except one. On the basis of this and previously reported experience, it is concluded that a substantial proportion of inferior left ventricular aneurysms exhibit the pathological features of false aneurysms. Because of the associated propensity toward rupture of such lesions, an aggressive surgical approach is recommended.

Aged↗
PubMed1979

Hepatitis risk in cardiac surgery patients receiving factor IX concentrates.

Experience with the clinical use and hepatitis risks of factor IX concentrate (Proplex) in cardiac surgical patients is presented in this report. Seventy-five patients received the concentrate for severe intraoperative or postoperative hemorrhage and 75 patients constituted matched controls. The incidence of probable type B viral hepatitis in patients receiving factor IX concentrate was 13.8 percent (four of 29) versus zero percent (zero of 29) in control patients (difference not significant). However, there was a greater incidence (p less than 0.05) of anti-HBs in patients receiving factor IX concentrate as compared to control subjects. No hepatitis-associated deaths or major morbidity were noted in these patients. It is confirmed that factor IX concentrate carries an associated significant risk of hepatitis. However, its use is justified in certain severe, acquired coagulopathies in which conventional platelet and fresh-frozen plasma therapy is inadequate.

California↗
PubMed1979

Operative treatment of aortic dissections. Experience with 125 patients over a sixteen-year period.

An unselected, consecutive cohort of 125 patients underwent operative repair of acute and chronic aortic dissections with tubular graft interposition over a 16 year span. The absence of remote geographical referral biases and the unselected nature of this series provided a patient population that was representative of the disease process (as assessed heretofore only from autopsy series). Furthermore, this enabled high-risk subsets to be defined by retrospective analysis. Patients were classified according to whether the ascending aorta was involved (type A with involvement, type B without), irrespective of the site of intimal tear, and according to age of the dissection: Fifty-three patients had acute type A (Ac-A), 29 had chronic type A (Ch-A), 20 had acute type B (Ac-B), and 23 had chronic type B (Ch-B) dissections. Fourteen percent (17/125) of the dissections had ruptured. Concomitant aortic valve replacement (AVR) was performed in 11% (6/53) for Ac-A cases and 38% (11/29) of the Ch-A cases. A total of 391 patient-years of follow-up was analyzed; follow-up averaged 4.5 years and extended to 13.7 years. Over-all operative mortality rate was 34% (18/53) for Ac-A, 14% (4/29) for Ch-A, 45% (9/20) for Ac-B, and 22% (5/23) for Ch-B; during the most recent 5 year interval these figures were lower: 27%, 8%, 20%, and 20%, respectively, N = 50. Multiple preoperative variables were found to correlate significantly with both operative death and long-term survival. Operative survivors generally experienced satisfactory functional benefit. Late attrition averaged 8% per year; 61% of all late deaths were related to cardiac or cerebral causes. Over-all actuarial survival (+/- SEM) for the entire cohort was 54% +/- 5% at 5 years and 26% +/- 7% at 10 years; for the 89 patients surviving operation, these figures were 76% +/- 5% and 37% +/- 10%, respectively. No significant differences in long-term survival were evident between the different subgroups. Whether the primary intimal tear had been resected or concomitant AVR had been performed had no statistically significant bearing on operative mortality, functional result, necessity for late reoperation, or late attrition. The long-term "natural" history of surgically treated patients with aortic dissections, as defined in this study, should facilitate comparison with other treatment modalities. Results of the present analysis support immediate operative intervention for patients with Ac-A dissections and probably for those with Ac-B dissections. Additionally, surgical treatment of patients with symptomatic or enlarging Ch-A and Ch-B dissections provides satisfactory rehabilitation and long-term survival. Finally, we re-emphasize our recommendation for simplified classification of aortic dissections, based solely upon the presence or absence of ascending aortic involvement. Pathophysiology and expected biologic behavior pivot on this feature, and appropriate clinical strategy can thereby be defined.

Adult↗
PubMed1978

Localized tamponade of the right atrium and right ventricle: induction of intracardiac right-to-left shunting after the use of a Gott shunt.

After repair of a traumatic tear of the descending aorta, using a Gott shunt between the left ventricle and the distal descending aorta, a patient was readmitted with profound postural cyanosis and dyspnea. Catheterization showed right-to-left shunting at the atrial level caused by extrinsic deformation of the right atrium and right ventricle. Sternotomy showed selective pericardial tamponade on the right side of the heart caused by a localized collection of organizing thrombus and old blood. The previously unsuspected large patent foramen ovale was closed. This complication represents a form of iatrogenic cyanosis tardice and is thought to be attributable to the method of shunting used during the first operation. Moreover, this complication should be easily preventable if the pooled blood and clot in the most dependent portion of the pericardial cavity is adequately evacuated.

Adult↗