Selection of a prosthesis for aortic valve replacement.
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Aged↗
Biomedical subjects
A Starr
Publications and source records attributed to A Starr.
Tissue and mechanical valves: mutually advantageous interplay.
This report is concerned with the dynamic interplay between glutaraldehyde preserved tissue valves (bioprostheses) and mechanical valves. These two classes of valve replacement devices are not competitive, but provide some nonoverlapping characteristic advantages and disadvantages. By proper selection, it may be possible to tailor the kind of device used for a particular patient, thus improving the overall results of bioprosthetic and mechanical valve replacement. Careful selection of patients according to age and the safety of anticoagulation should achieve a series of patients with mechanical and bioprosthetic valves that would be superior to a series in which all patients received a single device. Thus, these devices should be viewed as complimentary rather than competitive since the value of properly matching a prosthesis to the patient will be reflected in improved overall results with each class of prosthesis.
Age Factors↗
Twenty-five year experience with Starr-Edwards heart valves: follow-up methods and results.
A prospective data registry and follow-up service has been in use for cardiac surgery patients at the St Vincent Hospital Heart Institute, Portland, Oregon, since 1960. It presently contains information on more than 4,000 heart valve operations. The physical system has evolved from a manually updated binder of flowsheets to an integrated multicomputer database. The caged-ball valves used as the predominant replacement device have themselves performed successfully, permitting a remarkable 25-year review. The conclusions from a current review of the valves, which have just entered their third decade of use, remain the same as the conclusions from an earlier review of the same series, performed 10 years ago when the valves had just entered their second decade of use.
Aortic Valve↗
Late results of ascending aorta-descending aorta bypass grafts for recurrent coarctation of aorta.
Ten patients between the ages of 10 and 17 years underwent ascending aorta-descending aorta bypass grafts for recurrent coarctation at the Oregon Health Sciences University from 1975 to 1984. The combined approach through a left thoracotomy and median sternotomy was used in all the patients. This operation was used when the segment of recoarctation was long, dense adhesions were present, collaterals were inadequate, or when a cardiac operation was necessary for an associated lesion. All the patients survived the operation, and the long-term results to date have been satisfactory.
Adolescent↗
Temporal relationship between single unit activity in superior olivary complex and scalp-derived auditory brainstem response in guinea pig.
Single unit activities in the region of the superior olivary complex were recorded from 8 guinea pigs concurrently with the recording of auditory brainstem potentials from the scalp. At any one anatomical site, be it a fiber tract (e.g. trapezoid body) or a nucleus (e.g. medial nucleus of the trapezoid body), the modal latency of the onset discharge of the units encountered corresponded in time with the latencies of several different waves (waves P2-P5) of the auditory brainstem response (ABR). Moreover, at the time of occurrence of just one of the ABR waves, single units in several diverse anatomical sites in and around the superior olive were found with modal latencies of onset discharge at that same time period. The slopes of the latency/intensity functions for both the peaks of the ABR and the modal latency of the onset discharge for most of the single units studied in the superior olive and its adjacent fiber tracts were remarkably similar. These data support the hypothesis of multiple rather than single generator site(s) for components of the ABR, at least, for waves P2-P5 in the guinea pig. These data do not distinguish whether the ABR are generated in part by travelling nerve action potentials or graded synaptic events.
Acoustic Stimulation↗
Selectivity of attenuation (i.e., gating) of somatosensory potentials during voluntary movement in humans.
Attenuation of somatosensory evoked potentials (SEPS) recorded from the scalp during voluntary movement occurs for specific combinations of the finger moved and the peripheral nerve stimulated. The cerebral potential component occurring at a latency of 27 msec (P27) evoked either by stimulation of median nerve at the wrist or by stimulation of 1st and 2nd digit nerves in the fingers were selectively attenuated during movement of 1st digit but were not altered during movement of 5th digit. By contrast, the cerebral P27 component evoked by stimulation of ulnar nerve at the wrist or by stimulation of 5th digital nerve were attenuated during movement of that digit but were not altered during movement of 1st digit. Gating of somatosensory activity is a selective phenomenon occurring when movement involves the areas being stimulated.
Electric Stimulation↗
Aortic valve replacement for acute Takayasu's disease.
A patient with aortic insufficiency secondary to Takayasu's disease who was treated by aortic valve replacement during active aortic inflammation is described. The patient remains well 29 months postoperatively with minor additional treatment. A review of aortic insufficiency in Takayasu's disease is presented.
Adult↗
A tri-institutional comparison of tissue and mechanical values using a patient-oriented definition of "treatment failure".
Selection of valve type for predominant usage is obscured by limiting the analysis to prosthesis-related rather than patient-oriented failure modes. In this report, "treatment failure" is defined as a valve-related death or permanent patient disability; successful reoperations are excluded, and emboli with permanent residua are included. Results with the Starr-Edwards Silastic ball valve (Oregon) and the Hancock (Stanford) and Carpentier-Edwards (Vancouver) porcine valves are compared using this new definition of treatment failure. Evaluated according to structural failure, the mechanical valve is superior to the tissue valve, and using the Stanford definition of valve failure, it becomes so between 5 and 10 years. Using treatment failure, tissue valves are superior at 5 years; at 10 years in the aortic position, the results are comparable; and in the mitral position at 8 to 10 years, tissue valves show a continued but small advantage.
Aortic Valve↗
Localization, timing and specificity of gating of somatosensory evoked potentials during active movement in man.
Short latency somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded at different times simultaneously and after an order to move the ipsilateral thumb (0, 100, 200, 300, 400 and 780 ms). Brain potentials were derived from surface electrodes over the scalp at contralateral postcentral and precentral sites and muscle potentials were derived from surface electrodes over the thenar eminence. Ipsilateral thumb movement did not affect the early lemniscal P14 or the postcentral cortical N20 but was accompanied by attenuation of the cortical postcentral P27 and cortical precentral P22, N30 and P45. These results suggest that the gating induced by voluntary movement in man occurs at thalamocortical level and that the differential effect on postcentral N20 and precentral P22 may represent the activity of different generators. Gating of SEPs during voluntary movement begins approximately 80-100 ms before EMG onset, is maximal at the time the EMG is maximal, and returns to control values after the EMG is concluded. These results suggest that the gating that precedes the onset of EMG activity is related to premotor events in the cerebral cortex and not to centripetal influences. Gating of SEPs to median nerve stimulation was localized to movements of areas innervated by the median nerve, that is, the ipsilateral thumb, index or middle finger, but not to movements of ipsilateral little finger or contralateral thumb.
Adolescent↗
Electrophysiologic studies in selective dorsal rhizotomy for spasticity in children with cerebral palsy.
A group of 20 children with spastic cerebral palsy underwent selective dorsal rhizotomy for alleviation of spasticity. Pre- and postoperatively, cortical somatosensory evoked responses (cSSEP), H reflex and F wave studies were done. Clinically there was dramatic reduction of tone without noticeable sensory loss. The electrophysiologic studies showed several findings: (1) many children have abnormal cSSEP preoperatively; (2) surgery seldom leads to a loss of cSSEP; (3) in many patients, there is a noteworthy improvement in the cSSEP wave form; (4) some children have electrophysiologic evidence of spinal cord dysfunction preoperatively and (5) Hmax/Mmax ratio decreases after surgery confirming decrease in tone.
Cerebral Palsy↗
Attenuation of auditory-evoked potentials during voluntary movement in man.
Long-latency auditory evoked potential (AEP) amplitudes were reduced during voluntary thumb movement. The cerebral component N100 did not change during the movement. By contrast, the cerebral potential P200 and N100-P200 amplitudes were attenuated during the motor task compared to control. This report cannot clearly distinguish if the attenuation obtained in the AEP during the performance of the movement is related to motor events in the cerebral cortex causing 'gating' or to other factors such as habituation or vigilance changes.
Auditory Threshold↗
Event-related potentials in disordered short-term memory in man.
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Acoustic Stimulation↗
Disordered auditory short-term memory in man and event-related potentials.
Four patients with conduction aphasia and impaired auditory but relatively preserved visual digit spans were tested in a task of short-term memory, a digit probe identification task, in both the visual and auditory modalities. Five age-matched normal subjects served as controls. Behavioural measures of response accuracy and reaction time and scalp derived event-related potentials were determined as a function of the number of items to be remembered. These measures were also recorded in a task requiring the detection of infrequent stimuli ('oddball' paradigm). The patients' performance and event-related potential wave forms for the 'oddball' task were no different from those of the controls. In the digit probe identification tasks the patients showed a reduction in amplitude of a positive component at a latency of approximately 450 ms (P450) of the event-related potential to correctly identified probes in the auditory modality. This component was within normal limits with visual testing. There was an inordinate increase in the patients' reaction time to auditory but not visual stimuli when the number of items to be remembered increased from one to three. Event-related potentials were also analysed as a function of speed of reaction time, position of the matching item in the stimulus presentation set and whether the probe was correctly identified as being in-set or out-of-set. Event-related potentials associated with fast reaction times in the auditory task when a single item was presented were no different between patients and controls, indicating that patients were capable of both performing normally and generating normal potentials on some trials. The data suggest that the deficit in auditory short-term memory in these patients occurs during stimulus classification.
Adult↗
Cerebral cortical contributions to sensory evoked potentials: hydranencephaly.
The contribution of the cerebral cortex to the generation of sensory evoked potentials was studied in an infant with hydranencephaly. On CT scan no tissue above the thalamus was noted. Long-latency potentials to auditory stimuli were absent whereas the short-latency or brain-stem auditory evoked potentials and some of the components of the middle latency auditory evoked potentials (No and Po) were present. To visual stimulation only the electroretinogram was detected. To somatosensory stimulation only the spinal cord potentials could be detected. The absence of long-latency components in each of the sensory modalities supports the concept that these potentials require intact cerebral hemispheres in man.
Anencephaly↗
Latency variability and temporal interrelationships of the auditory event-related potentials (N1, P2, N2, and P3) in normal subjects.
Peak latency variation and the temporal interrelationships of the auditory event-related potential were investigated in 12 normal adults (ages 28-42). Measures of variation were based on both conventional averages and single trials. Estimates of N1, P2, N2 and P3 latencies were made on a trial-by-trial basis to target stimuli recorded from Fz, Cz and Pz scalp locations. Results showed that single-trial latency variability of the auditory ERP differed both among the various components and between subjects. Larger standard deviations were measured for the later N2 and P3 components than the earlier N1 and P2 components. Regression analyses between various component latencies indicated a strong covarying relationship between N2 and P3, with N2 accounting for up to 61% of the variance of P3 latency at Pz. Earlier N1 and P2 components added little to the overall prediction of either P3 or N2. For the other components, P2 accounted for 9-16% of the variance of N2, while N1 accounted for approximately 1% of the variance of N2; N1 accounted for 8-10% of the latency variation of P2. The correlations between single-trial peak latencies and RTs were positive but of low magnitude. The highest correlations between peak latency and RT were found for N2 (r = 0.33) and P3 (r = 0.24). The low correlations between the single-trial latencies of N1 and P3 suggest that the processes reflected by these components are independent and support a distinction between the earlier and the later components of the ERP. The close temporal coupling between N2 and P3 suggests that N2 may reflect cognitive properties in common to P3 in stimulus evaluation processes.
Adult↗
The thoracic surgical industrial complex.
The thoracic surgical industrial complex is an industry worth $2 billion per year and is shaped by six dominant forces, three positive and three negative. The three positive forces are technological innovation, entrepreneurial activity, and the flow of capital and the three opposing forces, government regulation, cost-containment, and the excessive costs of product liability insurance. We are now at a critical time in the evolution of this industry, with growth being enhanced in areas of lesser risk, namely, nonimplantable devices, at the expense of high-risk implantable devices. The future of the artificial heart hinges on the balance between the six forces, and this analysis examines the possibilities for timely development of this ultimate implantable device.
Consumer Product Safety↗
Late right ventricular reconstruction following valvotomy in pulmonary atresia with intact ventricular septum.
Experience over two decades in the surgical management of pulmonary atresia with intact ventricular septum demonstrates that eventual right ventricular (RV) reconstruction is possible in the majority of patients surviving valvotomy in infancy. Ten of 17 operative survivors of early valvotomy have eventually received a patch graft to the RV outflow tract, with no reoperative deaths (mean follow-up, 7.4 years). RV systolic pressures, suprasystemic prior to reoperation, are near normal after outflow patch reconstruction. Serial cineangiograms show evidence of RV growth by measurement of tricuspid annulus diameter (TAD), and demonstrate a rate of growth [d(TAD)/d(body length)] greater than a normal rate derived from autopsy data. The mean TAD growth rate is significantly greater than that of patients with less favorable ventricle types treated with a systemic-pulmonary shunt alone. Measurement of TAD is a useful method for following RV growth, and may aid in selecting patients for RV reconstruction.
Adolescent↗
Severe mitral regurgitation in a woman with a double orifice mitral valve.
A 64 year old woman with partial atrioventricular canal and double orifice mitral valve presented with severe mitral regurgitation secondary to a torn leaflet. The double orifice regurgitant mitral valve is an unusual finding at operation.
Echocardiography↗