Thrombosis of mechanical cardiac valves: a qualitative comparison of the silastic ball valve and the tilting disc valve.

A review of 817 mitral and aortic Silastic ball valve implantations with a follow-up of 3,554 total patient-years yielded only seven cases of valve thrombosis. Time-related risk was 0.4% per patient-year in the mitral position and 0.1% per patient-year in the aortic position. Four of five mitral and one of two aortic ball valve thromboses were successfully managed by valve rereplacement . At least five of the seven patients presented with a prodrome (lasting at least 3 months) of symptoms of progressive heart failure and, occasionally, embolic episodes due to gradually increasing prosthetic stenosis by thrombus. This lengthy time course is in contrast to the more frequent rapid catastrophic thrombosis that occurs with the Björk-Shiley tilting disc valve. Recognition of the prodrome of Silastic ball valve thrombosis provides an opportunity for life-saving surgical intervention.

Focal facial spasm.

An unusual case of focal facial spasm modified by factors affecting the peripheral facial nerve was investigated in a 32-year-old woman with involuntary contractions at the left mouth and nasal area. Voluntary facial movements were normal. The involuntary spasms ceased with digital pressure over the facial nerve in the left stylomastoid area. A difference between voluntary and these involuntary facial movements occurred both with local anesthetic blockade and with crushing of the facial nerve. Blink reflexes demonstrated unilateral left synkinesis, and facial EMG showed clonic discharges and individual motor units that discharged rapidly (200 Hz). Treatment with diphenylhydantoin, carbamazepine, and prednisone was ineffective. Neurolysis of the peripheral facial nerve resulted in temporary relief, whereas biofeedback controlled the spasms. Focal facial spasms may represent a disorder of the facial nucleus influenced by both peripheral and central mechanisms.

Ball valve prostheses: current appraisal of late results.

Advanced actuarial techniques are used to analyze late results in 912 patients who had isolated mitral or aortic valve replacement with ball valve prostheses from 1965 to 1974. Experience with noncloth-covered and cloth-covered valves is compared in terms of late survival, rate of thromboembolic complications and reoperation and the influence of anticoagulation. The cloth-covered prostheses have substantially reduced the incidence of emboli after mitral valve replacement (1.9 vs. 6 emboli per 100 patient years) and have thus far eliminated emboli after aortic valve replacement in patients receiving warfarin. Patients with a cloth-covered aortic valve who did not receive warfarin had nine emboli per 100 patient years. The safety of cloth-covered valves is clearly enhanced by warfarin therapy; the efficacy of anti-platelet drugs is still uncertain. Strut cloth wear was found at reoperation in 10 patients. This should be prevented in the new model 2400 composite strut ("track") valve by a narrow metal track on the inner surface of each strut. The substantial recent reductions in operative mortality and in prosthesis-related complications pose important questions regarding timing of operations and selection of prostheses. These decisions must be individualized for each patient on the basis of a thorough analysis of late results using modern statistical methods.

Postoperative hemodynamic and electrophysiologic evaluation of the interatrial baffle procedure.

Hemodynamic and electrophysiologic studies were performed in 11 children with dextrotransposition of the great arteries an average of 26 months after the interatrial baffle procedure and, in 2 patients, additional closure of a ventricular septal defect. All children are clinically well. Right to left shunts ranging from 28 to 63 percent of systemic blood flow were found at the superior vena caval-baffle junction in four children. The superior vena caval-baffle gradient averaged 7 mm Hg (range 0 to 22). Right ventricular stroke work index averaged 39 g-m/beat per m2 and right ventricular end-diastolic pressure 9 mm Hg. These values were not significantly different from the values for the systemic left ventricle in a comparable group of normal children (average left ventricular stroke work index 45 g-m/beat per m2 and average left ventricular end-diastolic pressure 8 mm Hg). Cardiac index, heart rate and arteriovenous oxygen difference were also normal. No child has complete heart block. His bundle recording demonstrated normal H-V intervals (range 27 to 40 msec); 4 of the 11 had a prolonged A-H interval. Left ventricular systolic pressure was less than 40 mm Hg in all but two children who had significant subpulmonary stenosis. Pulmonary vascular resistance averaged 1.9 units and was decreased in all children. We conclude that up to 37 months postoperatively, despite some residual abnormalities, the clinical and hemodynamic condition of these children is excellent.

Combined intracardiac and extracardiac repair of scimitar syndrome with anomalous pulmonary veins to both cavae.

Anomalous pulmonary venous drainage from the right lung to the inferior vena cava (scimitar syndrome) is a rare finding. This paper briefly discusses this syndrome and presents a case of anomalous pulmonary venous return to both the superior and the inferior cavae, which was corrected with a combined extracardiac and intracardiac approach. Polytetrafluoroethylene was utilized for reconstruction of pathways to the left atrium. To our knowledge, this is the first time this technique has been used to correct this anomaly.

Pericardial baffle complications following the Mustard operation. Age-related incidence and ease of management.

Pericardial baffle complications with the standard Mustard operation led first to the use of alternative materials of various shapes and finally to the recent popularity of the Senning procedure. At The Oregon Health Sciences University, we have persisted since the mid-1960s in the use of a modified Mustard operation in which a rectangular pericardial baffle is employed. Among 75 patients, there were baffle complications necessitating reoperation in 13. The reoperation-free rates (+/- standard error) at 9 years for patients less than or equal to 6 months, 7 to 12 months, and greater than 12 months of age were 59% +/- 15%, 60% +/- 17%, and 95% +/- 5%, respectively. All 10 patients reoperated upon during the past decade survived with complete relief of symptoms. A double patch to widen both the superior portion of the baffle and the superior vena cava was used most commonly and is our current procedure-of-choice. Baffle complications after the use of pericardium can be managed easily and reoperation on these patients carries a low risk. However, even with experience, the incidence of reoperation remains high in patients under 1 year of age and prompts a critical age-related comparison of these late results with the Senning procedure.

Effects of infusion of cardiotomy suction blood during extracorporeal circulation for coronary artery bypass surgery.

The effects of infusion of cardiotomy suction blood during extracorporeal circulation were evaluated in 15 patients undergoing coronary artery bypass surgery without the use of a left ventricular vent. In Group I all cardiotomy suction blood was discarded. In Groups II and III cardiotomy suction blood was reinfused without and with Dacron wool filtration, respectively. Marked hematologic changes were noted in the pericardial samples which also were reflected in oxygenator samples obtained at the end of bypass. Although postoperative bleeding was significantly greater in patients from Group II as compared to Group I, no differences were seen in total intraoperative and postoperative transfusion requirements. No patient required reoperation for bleeding. Recirculation of larger volumes of cardiotomy suction blood potentially could contribute to bleeding problems in the immediate postoperative period.

Adventitial inversion technique in repair of aortic dissection.

We describe a new technique for aortic anastomosis in the repair of acute dissection. The aorta is buttressed by inverting the adventitia without the use of Teflon or other synthetic materials. This technique provides a safe and secure anastomosis.

Effects of myelin or cell body brainstem lesions on 3-channel Lissajous' trajectories of feline auditory brainstem evoked potentials.

Auditory brainstem evoked potentials (ABEP) were recorded from 16 awake cats to obtain 3-Channel Lissajous' Trajectories (3CLTs) using three orthogonal differential electrode configurations (nasion-midline nuchal ridge, left-right mastoids, vertex-midline under the mandible). Potentials, evoked by monaural 80 dBnHL (re, human threshold) clicks, were studied before, and up to 7 weeks after inducing neuronal lesions localized to the cochlear nucleus (CN) or the superior olivary complex (SOC), or myelin lesions localized to the fibers of the trapezoid body connecting these two structures. Neuronal lesions were induced by injection of kainic acid (KA), while myelin lesions were induced by injection of L-alpha-lysophosphatidylcholine (LPC). With CN neuronal lesions the major changes in 3CLT were in the time domain of 'b', 'c' and 'd' (components P2, P3 and P4 of single-channel ABEP). With SOC neuronal lesions the major changes were in 'c' and 'd' of 3CLT (P3 and P4 of ABEP). With trapezoid body lesions the major change was in 'c' (P3 of ABEP). The results are compatible with the peripheral generation of the first ABEP components (P1a and P1b). The second component (P2) is generated by ipsilateral CN neurones and their outputs. The third component (P3) is generated primarily by ipsilateral SOC neurones and their outputs, with the ipsilateral CN providing input. The The fourth component (P4) is generated bilaterally by the SOC neurones and their outputs, receiving their inputs from ipsilateral CN. The fifth ABEP component (P5) is generated by structures central to the SOCs and their immediate outputs. Neither focal neuronal nor myelin lesions were sufficient to produce obliteration of any component, consistent with a set of generators for each of the ABEP components, consisting of both cell bodies and their output fibers, that is distributed spatially in the brainstem.

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.

Mitral valve replacement with ball valve prostheses.

Our experience with ball valve replacement of the mitral valve during the past decade is presented in terms that allow comparison with other techniques. The use of such prostheses is characterized by ease of implantation, with an overall operative mortality of 11 per cent for isolated mitral replacement and 13 per cent for multiple valve replacement. The operative mortality for isolated mitral valve replacement during 1969 and thus far in 1970 has been nil. The late mortality was 13 per cent for isolated mitral replacement and 20 per cent for multiple valve replacement. Forty-three per cent of the total late deaths were clearly unrelated to the prosthetic device itself. The overall incidence of late infection and leak is less than 1 per cent and the immediate haemodynamic benefit is not altered by loss of structural integrity of the prosthesis. The most serious problem after mitral valve replacement with the ball valve prosthesis is that of thromboembolic complications. While thrombotic stenosis of the prosthesis is a rarity, embolic episodes, usually cerebral in type, have been noted in 63 per cent of the patients surviving mitral valve replacement with the earliest model ball valve from August 1960 to February 1966. Improvements in valve design have resulted in a remarkable decrease in this incidence as examined by actuarial techniques and taking into account the duration of follow-up. The extension of the cloth sewing margins to the orifice of the valve while maintaining a metallic orifice and metallic cage (Model 6120) resulted in a drop of the thromboembolic rate to 17 per cent from April 1965 to April 1969. The development of the totally cloth-covered prosthesis has further improved these results, with only one thromboembolic complication after isolated mitral valve replacement with the Model 6310 valve in a series of 66 consecutive patients. In clinical practice this has resulted in the avoidance of the use of anticoagulant therapy in patients in whom for a variety of reasons this carries an increased hazard. With further follow-up it may be possible to discontinue the routine use of anticoagulants.

Identification of mitochondrial and non-mitochondrial glutaminase within select neurons and glia of rat forebrain by electron microscopic immunocytochemistry.

Antibodies against the mitochondrial enzyme glutaminase (EC 3.5.1.2), have been used in previous immunocytochemical studies to help identify glutamate-releasing neurons among all glutamate-containing neurons. The studies were based on the idea that glutaminase is enriched within the releasable "transmitter" pools of glutamate. However, evidence is also available to suggest that the enzyme does not occur exclusively within glutamate-releasing neurons. Thus we sought to determine whether glutaminase was immunocytochemically detectable within presynaptic terminals forming asymmetric (putatively excitatory) synapses or, alternatively, occurs in association with mitochondria throughout the cell. For this purpose, we examined the cellular and subcellular distribution of glutaminase- immunoreactivity in neocortical (visual and somatosensory) areas known to contain glutamatergic perikarya. This localization was compared with the distribution in striatal (caudate-putamen and nucleus accumbens) regions recognized to contain high densities of glutamatergic terminals but fewer, if any, glutamatergic perikarya. Glutaminase-immunoreactive perikarya were numerous within the infragranular laminae of neocortex (approximately 1 per 1,000 microns 2 tissue area) but sparse within the caudate-putamen nuclei and accumbens nuclei (less than 1 per 20,000 microns 2.). In addition, heterogeneous distribution of small (less than 1 microns) punctate immunoreactive structures was notable. Relatively high densities of these punctate structures occurred within the supragranular laminae of neocortex, dorsolateral quadrant of the caudate-putamen nuclei, and surrounding certain groups of myelinated fiber bundles throughout the striatum. Electron microscopy revealed diffusely distributed peroxidase immunoreactivity in a select population of dendritic spines, glial processes, and axons. Eight percent of all synapses within the supra-granular laminae were formed by terminals labeled for glutaminase. These principally formed asymmetric junctions on spiny processes. When tissue was incubated with the antibody in the presence of a permeabilizing agent, Photo-flo, high levels of glutaminase immunoreactivity was detectable by electron microscopy within select mitochondria of neocortical (4%) and striatal (8%) perikarya and dendrites, while the diffuse distribution of immunoreactivity within axons and glia was greatly diminished. The differential ultrastructural conditions provide direct demonstration that glutaminase in brain occurs in at least two forms discriminable by their diffuse distribution within non-mitochondrial cytoplasm versus discrete localization within mitochondria. The morphological characteristics of synapses formed by axons exhibiting diffuse distributions of glutaminase immunoreactivity are consistent with the idea that glutaminase-enriched terminals mediate excitatory chemical transmission via the release of glutamate. Because glia containing glutaminase occur juxtaposed to the asymmetric junctions, the glia may utilize neuronally released glutamate for energy metabolism.

Experimental use of fluoroalkyl cyanoacrilate in ureteral anastomosis.

A fluorinated tissue adhesive Fluoroalkyl Cyanoacrilate has been used in end-to-end ureteral anastomoses as an adjunct to suture material to avoid urinary extravasation in seven dogs. A similar number of dogs served as controls. The urinary tracts were evaluated grossly, radiographically, and histologically after 3 to 12 months. Better anatomical results and less inflammatory reaction and fibrosis were found in the group submitted to the tissue adhesive.

Superior vena cava obstruction after Mustard repair of d-transposition of the great arteries.

Superior vena caval obstruction following Mustard repair of d-transposition of the great arteries is usually relieved by partial or complete revision of the intra-atrial repair. We employed a different approach in a patient with isolated total obstruction of the superior vena caval pathway, who suffered from fatigue, venous congestion in the upper part of the body and mild hydrocephalus. A 12 mm polytetrafluoroethylene tube was interposed between the left innominate vein and the left (functionally right) atrial appendage. Early and medium-term relief was demonstrated by repeat catheterization of the right heart and computed tomography brain scan three months postoperatively. The rationale for use of prosthetic material in the venous system is discussed and the need for long-term follow-up is stressed.

Mitral replacement: clinical experience with a ball-valve prosthesis. Twenty-five years later.

The purpose of this report is to review the results of mitral valve replacement since a first report in the Annals of Surgery in 1961, in order to determine the relative importance of new valve designs versus other surgical variables. The continued use of the silastic ball valve in its 1966 configuration (Model 6120), by providing a comparative data base for other new prosthetic valves, allows this analysis. For a valid comparison with the tilting disc (Bjork-Shiley) and the porcine (Hancock and Carpentier-Edwards) valves, only results with the silastic ball valves implanted during comparable time frames should be used. (Formula: see text) Thus, there are no significant differences in the results obtained with the silastic ball valve in time frames comparable to other contemporary valves introduced in the early 1970s. Improved results, therefore, must be non-prosthetic valve related.

Thrombotic and embolic complications with silastic ball prosthetic valves.

Eighteen years of continuous clinical use with the Starr-Edwards ball-valve prosthesis provides an extensive data base for comparison with more recently introduced cardiac prostheses, and establishes the credentials of this valve for current clinical use. Since 1965, 558 aortic (model 1260) and 285 mitral (model 6120) ball-valve prostheses have been inserted at the University of Oregon. Thromboembolic rates for the entire series (1965-1983) and our more recent experience (1973-1983) were 3.8% per year and 2.8% per year for the aortic valve; and 5.1% per year and 2.6% per year for the mitral valve. Patients who had experienced one embolic episode were substantially more likely to experience a subsequent event. Thrombotic stenosis was seen at rates of 0.1% per patient year and 0.4% per patient year for the aortic and mitral valves, respectively. These results are compared with other current series using a variety of mechanical and tissue prostheses. The Starr-Edwards valve remains a durable mechanical cardiac prosthesis with thromboembolic complications similar to most other current prostheses. Thrombotic stenosis tends to be rare, gradual, and electively managed as opposed to the sudden, unpredictable, and catastrophic thrombosis seen with tilting disc valves.