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Biomedical subjects

B A Reitz

Publications and source records attributed to B A Reitz.

At least 235 records · Page 13Linked to original sources
PubMed1980

A surgical approach for S,L,L single ventricle incorporating total right atrium--pulmonary artery diversion.

Patients with single ventricle and unfavorable anatomy for partitioning procedures have been considered inoperable. Such was the case in two patients with single ventricle and subaortic inverted (hypoplastic) infundibulum associated with subaortic obstruction and levo-transposition of the great vessels (S,L,L). Both had undergone pulmonary artery banding in infancy and presented 11 and 14 years later, cyanotic and severely incapacitated. Both patients were treated surgically by resection of the subaortic obstruction, patch closure of the right artrioventricular valve, closure of the proximal pulmonary artery, and diversion of systemic venous flow through a xenograft valved conduit from the right atrium to the distal pulmonary artery. Early postoperative complications included atrial dysrhythmias and right-sided congestion. The first patient, who had massive cardiomegaly and complete heart block preoperatively, developed congestive failure 20 months postoperatively. The second patient has an excellent functional result and is leading a normal life 1 years after operation. This procedure may be of value for patients with single ventricle in whom corrective ventricular septation is considered too risky or technically unfeasible.

Adolescent↗
PubMed1980

Hemodynamic and clinical comparison of the Hancock modified orifice and standard orifice bioprostheses in the aortic position.

Bioprosthetic aortic valve replacement in patients with a small aortic root has been associated with postoperative transvalvular gradients. A modified orifice Hancock xenograft bioprosthesis has been developed and is purported to increase significantly the effective orifice area (as evaluated by in vitro testing) compared to the standard orifice Hancock bioprosthesis. To assess the in vivo differences, we compared 481 patients with standard orifice prostheses with 156 patients with modified orifice prostheses. Postoperative catheterization was performed in 24 patients with modified orifice (valve diameters 19 to 25 mm) with 14 with standard orifice valves (valve diameters 21 to 25 mm). Actuarial rates of survival, valve failure, endocarditis, and thromboembolism did not differ significantly between the two subgroups. Peak aortic valve gradients on the whole were less in the modified orifice subgroup than in the standard origice subgroup (12 +/- 1 torr versus 20 +/- 6 torr [mean +/- SEM]), but the difference was not statistically significant (p greather than 0.05). The calculated in vivo aortic valve areas were slightly, but insignificantly, greater in the modified orifice subgroup than in the standard orifice subgroup (p greater than 0.05). These in vivo data partially corroborate the in vitro findings of increased effective orifice area and internal-to-external diameter ratio for the modified orifice bioprosthesis. The hemodynamic differences between the two valve types are small, however, and the putative clinical advantages inherent in the use of the modified orifice bioprosthesis remain to be completely defined.

Aortic Valve↗
PubMed1980

Operative treatment of a giant cerebral artery aneurysm with hypothermia and circulatory arrest: report of a case.

A patient with a giant left middle cerebral artery aneurysm is presented. Because of previous operations and dense adhesions of the dominant frontal and temporal lobes to the aneurysm sac, we elected to obliterate the aneurysm by endaneurysmorrhaphy with the patient under hypothermia and cardiac arrest. Elective cardiac arrest has become a relatively safe, controllable procedure and may be of significant value in the treatment of difficult neurosurgical problems.

Adult↗
PubMed1980

Clinical durability of the Hancock porcine bioprosthetic valve.

The principal feature of the Hancock xenograft bioprosthesis which remains to be completely defined is long-term durability. This report provides extended data regarding valve durability derived from a data base of 1,407 patients (707 aortic [AVR] and 700 mitral [MVR] replacements) who received Hancock bioprostheses between 1971 and 1979; cumulative duration of follow-up was 1,732 patient-years for AVR and 1,843 for MVR patients, with a maximum follow-up duration of 8.4 years. One hundred seventy-nine patients were followed for more than 5 years and 67 for more than 6 years. Valve failure was defined on the basis of one or more of the following criteria: (1) postoperative development of a new regurgitant murmur, (2) thrombotic valvular occlusion, (3) infective endocarditis resulting in reoperation or death, and (4) hemodynamic valvular dysfunction confirmed by catheterization and resulting in reoperation or death. Twenty-one such failures occurred among all AVR patients and 23 among all MVR patients. The actuarial probability of freedom from valve failure (all causes) was 95.4% +/- 1.2% (+/- SEM) for adult AVR patients 5 years postoperatively and 90.9% +/- 2.6% for adult MVR patients 6 years postoperatively. The probability of freedom from primary tissue failure in adults was 99% +/- 1% in AVR patients at 5 years and 94.3% +/- 2.4% in MVR patients at 6 years. The linearized incidence of primary tissue failure in children (< 15 years old) was 9.8% per patient-year (combined AVR and MVR patients), compared to 0.2% per patient-year among all adult patients in the analysis. The combined actuarial incidence of primary tissue failure among adults with AVR and MVR was 98.6% +/- 0.7% at 5 years and 94.2% +/- 2.3% at 6 years; thus there appears to be a slight acceleration in the rate of valve tissue failure between 5 and 6 years after operation. The incidence of failure, however, remains acceptably low through 6 years of follow-up, and continued clinical use of the xenograft bioprosthesis seems warranted.

Actuarial Analysis↗
PubMed1979

Survival of heart allografts in rats treated with azathioprine and sodium salicylate.

In a rat heart transplant model representing a severe mismatch, median survival time (M.S.T.) with no treatment was 6 days. M.S.T. with azathioprine was 6 days, and with azathioprine and methylprednisolone 7 days. Azathioprine with promethazine hydrochloride gave an M.S.T. of 15 days. In rats treated with sodium salicylate alone M.S.T. was 16 days, and when azathioprine was administered for 12 days in a group continuously treated with sodium salicylate, all hearts were beating normally at 50 days.

Animals↗
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

Role of tachycardia as an inotropic stimulus in man.

We examined the inotropic effect of tachycardia in nine postsurgical aortocoronary bypass graft patients (with intact cardiac innervation) and nine cardiac allograft recipients (with denervated hearts). The changes in stroke volume (SV) and velocity of circumferential fiber shortening (VCF) which accompany sudden increases and decreases in atrial pacing frequency were determined by computer-aided fluoroscopic analysis of the motion of surgically implanted midwall myocardial markers. Because the first beat after a change in rate retains the frequency characteristics of the preceding rate, we compared the first posttachycardia beat with control beats and late tachycardia beats with the first tachycardia beat; afterload and preload for each pair of beats were similar. For an increase in heart rate of 50 beats/min, SV and VCF rose 79 and 64% from the first tachycardia beat to late tachycardia beats, and SV and VCF rose 8 and 35% from control beats to the first posttachycardia beat in the innervated group. Responses in the denervated group were not significantly different from those in the innervated group. The degree of the inotropic response was positively correlated with the magnitude of the increase in heart rate (r = 0.91). The decay in augmented contractility after decreasing the rate back to control levels fits an exponential relationship with a mean t((1/2)) of 1.7 s. Thus, in conscious man, increases in heart rate represent a positive inotropic stimulus, independent of other factors influencing ventricular performance and unaffected by neural innervation, and should be considered when changes in cardiac function are interpreted during serial studies or after drug administration.

Adolescent↗
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

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↗