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Biomedical subjects

A Starr

Publications and source records attributed to A Starr.

At least 433 records · Page 24Linked to original sources
PubMedDate not supplied

Lessons learned before and after cardiomyoplasty: risk sensitive patient selection and post procedure quality of life.

BACKGROUND: This paper unveils some of the clinical lessons we have learned from caring for cardiomyoplasty patients over the past 7 years. We examine both the clinical and scientific rationale for expanding the time frame of "procedural mortality" from 30 days to 90 days. METHODS: Utilizing this definition of procedural mortality, preoperative patient variables were applied to postoperative patient outcomes in order to develop a risk sensitive method of patient selection. Preoperative atrial fibrillation, elevated pulmonary capillary wedge pressure, decreased peak oxygen consumption, and the requirement of intra-aortic balloon pump at the time of cardiomyoplasty, were all found to be independent risk factors for early death following cardiomyoplasty. RESULTS: This analysis, which has been previously published, is reviewed and enhanced with the mathematical equations for duplicating these relative risk calculations. The mathematical model presented herein allows a method of risk stratification, which obviates the need for randomized congestive heart failure controls in the future. In the absence of a statistically regulated control population, we also examine the 1-year clinical outcomes of the nonrandomizd control group of patients, who were followed during the North American FDA Phase II Cardiomyoplasty Trial. CONCLUSIONS: This quality of life comparison with cardiomyoplasty patients at 1 year revealed a significant decrease in intensive care unit patient-days, a significant increase in activity of daily living score, and a significant improvement in New York Heart Association functional class as compared to control.

Activities of Daily Living↗
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Effect of click rate on the latency of auditory brain stem responses in humans.

Auditory brain stem responses are the far-field reflections of electrical activity originating in the auditory pathway in its course from the cochlea to cortex that can be recorded from scalp electrodes using computer averaging techniques. There are seven components in the initial 10 msec following a click signal which have been shown to have an orderly change in latency as a function of signal intensity. The results of this study show that click repetition rate can also significantly affect the response latency measure. Responses were measured in six normal hearing subjects at click rates of 10, 30, 50 and 100/sec and af four intensity levels (30, 40, 50, and 60 dB sensation level). The mean latency shift of component V was approximately 0.5 msec when the responses at 10 and 100/sec were compared. This is equivalent to a 15-20 dB decrease in signal intensity at the 10/sec click rate. An analysis of the time of occurrence of this shift using brief click trains at 100/sec showed the shift in latency to be complete by the fifth click. The latency shift was similar at the four signal levels tested. The latency shift was similar at the four signal levels tested. The latency shift of component V appeared to be a monaural and therefore a potentially peripheral process. The results are interpreted as an objective measure of adaptation in the human auditory system with implications for the measurement in disorders of hearing.

Acoustic Stimulation↗
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Brain stem potentials evoked by electrical stimulation of the cochlea in human subjects.

Brain stem potentials were recorded from scalp electrode to biphasic square wave electrical stimulation of implanted electrodes in the cochlea of three patients. Reliable potentials could be recorded that appeared 1.5 to 2.0 msec prior to the customary acoustically-evoked brain stem potentials. The effects of variations in electrical stimulus parameters of rate and intensity were measured. Brain stem potentials can provide objective indices of the effectiveness of electrical stimulation of the cochlea in man.

Acoustic Stimulation↗
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Late results of mitral and aortic valve replacement.

Experience with isolated mitral and aortic valve replacement at the University of Oregon Medical School since 1965 is presented. Results with non-cloth-covered and cloth-covered valves were analyzed with actuarial techniques and were compared in terms of late survival, thromboembolic complication rate, reoperation rate and the influence of anticoagulation therapy. The cloth-covered prostheses have substantially lowered the incidence of emboli after mitral replacement, and have thus far eliminated emboli after aortic replacement in patients receiving warfarin. Although anticoagulation therapy is still necessary, a clinical trial is currently in progress to assess the adequacy of antiplatelet drugs. The choice of a cloth-covered or non-cloth-covered valve should be individualized for each patient, based on the different risks and benefits of each prosthesis.

Aortic Valve↗
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The lack of predictive value of preoperative psychologic distress for postoperative medical outcome in heart transplant recipients.

This follow-up study of 58 heart recipients an average of 2 years after transplantation did not show that the Symptom Checklist 90R, a self-report measure of psychologic distress, predicted medical outcome. Mortality and medical morbidity (graft rejection and infection rate) were the outcome variables used. The findings tend to argue against the validity of some aspects of the psychiatric screening of transplant candidates if prediction of patients' ultimate risk of mortality or medical morbidity is the validation standard.

Adult↗
PubMedDate not supplied

Late infection in cardiac allograft recipients: profiles, incidence, and outcome.

Infection continues to cause substantial morbidity and mortality after heart transplantation. Studies focusing on this problem have concentrated on the early posttransplant period, and it is uncertain to what extent infection continues to add to morbidity later after transplantation. Fifty-four patients surviving at least 1 year after heart transplantation made up the study population in this study, and they were surveyed for infections beyond 1 year. In this group there were 15 infections, an incidence of 0.3 infections per patient or 0.016 infections per patient-months of follow-up. Only nine of these infections necessitated hospitalization; two, however, were fatal. Actuarial risk of all late infections and late infections necessitating hospitalization was 13% and 6%, respectively, at 2 years. As expected, bacterial infections made up the largest group (60%), followed by viral disease (27%). Two patients had pulmonary infections, one with Aspergillus and one with Pneumocystis. These data demonstrate that although rates of infection in heart recipients continue to exceed those in the general population, the rates are considerably lower than those in what is seen early after heart transplantation. Despite this, the more unusual infectious agents associated with immune compromise continue to be present.

Actuarial Analysis↗
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Lack of progressive "restrictive" physiology after heart transplantation despite intervening episodes of allograft rejection: comparison of serial rest and exercise hemodynamics one and two years after transplantation.

It has been suggested that the cardiac allograft becomes less compliant either because of repeated episodes of rejection, chronic hypertension, or as a direct consequence of immunosuppression. A corollary to this hypothesis is that this reduction in compliance should be a progressive, rather than a static, change. To test this hypothesis, rest and exercise filling pressures, cardiac outputs, and radionuclide ventriculographic systolic and diastolic indices were measured in 20 patients at 1 and 2 years after heart transplant by means of identical protocols at both study times. Between studies 10 of 20 patients had no rejection, five of 20 had one rejection episode, and five of 20 had more than one rejection episode. There were no significant differences in resting or exercise heart rates, pulmonary wedge pressures, cardiac outputs, left or right ventricular ejection fractions, left ventricular peak filling rates, or time to peak filling between the studies at 1 and 2 years. Only resting right atrial pressure increased between year 1 and year 2 (6 +/- 2 mm Hg vs 8 +/- 4 mm Hg, p = 0.035). These data demonstrate that cardiac allograft function is unchanged between 1 and 2 years after transplantation, despite episodes of intervening rejection and continued immunosuppression. The data further suggest that the previously reported decrease in cardiac allograft compliance does not appear to be caused by a progressive intrinsic abnormality in the allograft, and that other mechanisms for "restrictive" allograft physiology should be sought.

Adolescent↗
PubMedDate not supplied

OKT3-induced hypotension in heart allograft recipients treated for steroid-resistant rejection.

OKT3 (a murine antihuman mature T cell antibody) has become an important therapeutic agent for the treatment of acute allograft rejection unresponsive to corticosteroid therapy. Seven heart allograft recipients received eight 10-day courses (one retreatment) of OKT3 for steroid-resistant rejection. All patients underwent hourly monitoring of vital signs, and one of the patients underwent hemodynamic monitoring during therapy. Age- and sex-matched kidney allograft recipients (including one retreated patient) undergoing the identical OKT3 antirejection protocol served as control patients. All patients had a measured decrease in arterial pressure during OKT3 therapy. The time from first dose to peak hypotensive response was identical in both heart and kidney allograft recipients (31 +/- 11 versus 32 +/- 11 hours, respectively, p = not significant [NS]) and did not coincide with the peak febrile response (22 +/- 12 versus 27 +/- 13 hours, respectively, p = NS). The decrease in mean arterial pressure was significantly greater in the heart allograft patients compared with the kidney allograft recipients (39 +/- 17 versus 22 +/- 10 mm Hg, respectively, p less than 0.03), despite a slightly greater positive fluid balance in the heart allograft recipients (1333 +/- 1991 versus 715 +/- 1224 ml, p = NS). The change in heart rate associated with the hypotension was only slightly and not significantly greater in the kidney allograft recipients. In the one heart allograft recipient undergoing hemodynamic monitoring, the decrease in mean arterial pressure was initially paralleled by a decline in systemic vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗
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Relation between recipient: donor body size match and hemodynamics three months after heart transplantation.

Cardiac allograft hemodynamics were compared with respect to donor and recipient body weights to determine whether recipient: donor body size match played a significant role in subsequent recipient hemodynamics. Thirty-four stable outpatients underwent resting right-sided cardiac catheterizations 3 months after heart transplantation. As expected, resting cardiac output correlated positively with recipient body weight (r = 0.50, p = 0.002), and mean cardiac index (2.7 +/- 0.6 L/min/m2) was normal. There was, however, only a weak and statistically insignificant correlation between recipient body weight and stroke volume (r = 0.31, p = 0.072). There was a statistically significant negative correlation between donor: recipient body weight ratio and right arterial pressure (r = 0.41, p = 0.017), pulmonary wedge pressure (r = 0.38, p = 0.027), and heart rate (r = 0.39, p = 0.024). These data demonstrate that although cardiac output is maintained at levels appropriate for recipient size after heart transplantation, patients who receive small hearts rely on an increased heart rate and elevated filling pressures to achieve this end. These data suggest that the cardiac allograft may not adapt to recipient body size by 3 months after transplantation.

Body Constitution↗
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Serial echocardiographic findings early after heart transplantation: evidence for reversible right ventricular dysfunction and myocardial edema.

Serial M-mode and two-dimensional echocardiograms were performed on 10 patients at 1 week, 1 month, and 3 months after heart transplantation to determine early structural and functional changes in the allograft. Standard M-mode echocardiographic measurements of at least five cardiac cycles were averaged. Right ventricular size and function were assessed by mid-ventricular diameter and the right ventricular apex to lateral tricuspid anulus shortening fraction, respectively, on the two-dimensional apical four-chamber view. There were no consistent differences in left ventricular end-diastolic dimension or fractional shortening between study periods. Left ventricular posterior wall thickness decreased from 15 +/- 2 to 11 +/- 1 mm (p = 0.001), and septal thickness decreased from 15 +/- 2 to 12 +/- 2 mm (p = 0.0006) between the 1-week and 3-month studies. Right ventricular cross-sectional dimension increased from 34 +/- 6 to 39 +/- 6 mm (p = 0.047), and right ventricular fractional shortening increased from 13% +/- 3% to 21% +/- 5% (p = 0.0051) between the 1-week and 3-month studies. There were no correlations between any of the above changes and rejection episodes. There was a weak correlation (r = 0.53) between ischemic time and change in posterior wall thickness. Right ventricular dysfunction and increased left ventricular wall thickness presumably caused by interstitial edema appear to be normal findings early after heart transplantation.

Adult↗
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Heart transplantation for cardiac amyloidosis: successful one-year outcome despite recurrence of the disease.

Systemic amyloidosis has been considered a theoretical contraindication for heart transplantation because of the concern that amyloidosis is a systemic disease that could potentially recur in the allograft. To date, no patients have been reported to have undergone heart transplantation. One year ago a patient with amyloidosis had a transplantation at the Oregon Health Sciences University, Portland. Results of kidney, rectal, and bone marrow biopsies were normal; however, endomyocardial and gingival biopsies showed positive results for amyloidosis. Recurrence of amyloidosis was detected by electron microscopy 14 weeks after transplantation; however, light microscopy has not shown any amyloidosis at 1 year. No other organ involvement has been documented. The patient is New York Heart Association functional class I, with normal resting hemodynamic parameters 1 year after transplantation. Amyloid heart disease does not necessarily portend a poor early outcome.

Amyloidosis↗
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Ten-year survival following aortic valve replacement: A multivariate analysis of coronary bypass as a risk factor.

The additional risk of coronary bypass surgery was analysed in 664 patients over 40 years of age undergoing aortic valve replacement between 1969 and 1981. Four hundred sixty-seven patients underwent aortic valve replacement alone, while 197 patients with coronary artery disease underwent combined aortic valve replacement and coronary bypass surgery. There were no significant differences in the preoperative hemodynamic characteristics of the two groups of patients. There were 41 (9%) operative deaths following aortic valve replacement alone and 20 (10%) following aortic valve replacement with coronary bypass surgery. Since 1976, operative mortality has fallen to 5% and perioperative myocardial infarction to 2% following the combined procedure. Ten-year actuarial survival (standard error) was 56 (3%) following aortic valve replacement and 49 (6%) following aortic valve replacement and coronary bypass surgery. A multivariate analysis including both groups of patients revealed that age, functional class and year of operation significantly affected ten-year survival (p less than 0.05). The same analysis showed that coronary artery disease requiring coronary bypass surgery also decreased ten year survival in patients undergoing aortic valve replacement (p = 0.06).

Aged↗
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A current appraisal of the Waterston shunt.

Recent reports have suggested that the classical Blalock-Taussig shunt and its prosthetic modification have a low patency rate in neonates. This prompted a review of 58 neonates undergoing a Waterston shunt for cyanotic congenital heart disease. The 4 mm anastomosis was constructed using a calibrated clamp. There were 20 (35%) hospital deaths, of which 3 were directly related to shunt failure. Operative mortality was associated with increasing complexity of the cardiac lesion, emergency operation, weight less than 3 kg and age less than 48 hours. There were 5 late deaths resulting in an actuarial survival of 52% at ten years. There was one case of late occlusion corresponding to a patency of 92% at 2 years. Anastomotic kinking with preferential flow to one lung occurred in 2 (7%) of 28 patients undergoing repeat angiography at 3 and 5 years respectively. Nineteen patients underwent corrective surgery a mean of 27 months after shunt construction. Six (32%) required an angioplastic repair of the pulmonary artery. Six (16%) of the 38 operative survivors required diuretic therapy for excessive pulmonary flow. The high patency ensures that the Waterston shunt continues to play an important role in the management of low weight neonates who require an emergency systemic-pulmonary shunt. The use of a calibrated clamp reduces the incidence of excessive pulmonary flow. Early corrective surgery and shunt dismantling may reduce the necessity for angioplastic repair.

Aorta↗
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Auditory brain stem potentials recorded at different scalp locations in neonates and adults.

The auditory evoked brain stem potential was recorded in 14 normal full-term infants and nine normal-hearing adults. Silver-silver chloride electrodes were placed at nasion, forehead, vertex, each mastoid over the bony prominence, and the seventh cervical vertebra (noncephalic reference) in order to study the scalp distribution of the auditory brain stem response. Large differences in the scalp distribution between the newborn and adult populations were observed. At the ipsilateral mastoid, an x wave occurring at approximately 2 ms and a y wave occurring at approximately 3.3 ms were identified in the adult; this contrasts to a y wave at approximately 3.7 ms in the neonate. It appears that there are either separate generators for some of the components in the adult versus the neonate, and/or as the nervous system matures, myelinization occurs with a concomitant change in the scalp distribution of the auditory brain stem potentials.

Adult↗
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The unnatural history of valvular heart disease: late results with silastic ball valve prostheses.

The development of prosthetic heart valves successfully arrested the dismal natural history of valvular heart disease for thousands of patients. The experiences of numerous investigators provided a setting wherein the design and implantation of the silastic ball valves led to improved survival with both aortic and mitral valve replacement. Refinement of the caged-ball design was based on clinical and laboratory findings. In the mitral position, valve related thromboembolism was reduced from 38% to 3%. With the aortic prostheses the problem of ball variance was overcome by reducing trauma to the poppet and altering its heat curing process. In 1967 a completely cloth covered valve was introduced to reduce further the thromboembolic rate. Significant improvement in the embolus-free rate was ultimately found to be dependent on the year of operation with introduction of the time-frame concept. The current mitral silastic ball valve, Model 6120, yields an actuarial survival of 72 (+/- 3%), 54 (+/- 5%), and 37 (+/- 5%) for five, ten and fifteen years respectively. For aortic valve replacement, current Model 1260, the actuarial survival is 71 (+/- 2%), 58 (+/- 3%) and 48 (+/- 4%) for five, ten and fifteen years respectively. Late results are compared to other valvular prostheses.

Aortic Valve↗