80 results on '"Stephenson, L W"'
Search Results
2. The Preservation of Type Specimens
- Author
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Stephenson, L. W.
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- 1933
3. Tryonella, a New Generic Name for Tryonia Stephenson, Preoccupied
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Stephenson, L. W.
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- 1951
4. Cypraea corsicanana, New Name for Cypraea gracilis Stephenson, Preoccupied
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Stephenson, L. W.
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- 1948
5. A new configuration for right ventricular assist with skeletal muscle ventricle. Short-term studies.
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Niinami, H, primary, Hooper, T L, additional, Hammond, R L, additional, Ruggiero, R, additional, Pochettino, A, additional, Colson, M, additional, and Stephenson, L W, additional
- Published
- 1991
- Full Text
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6. Spontaneous right ventricular rupture after sternal dehiscence: a preventable complication?
- Author
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Arbulu, A, Gursel, E, Camero, L G, Asfaw, I, and Stephenson, L W
- Abstract
Mediastinitis and/or sternal dehiscence developed in 143 out of 10,263 patients (1.4%) who underwent cardiac surgery between January 1979-December 1993. Mediastinal drainage, sternal debridement and early wound closure with pectoralis major and/or rectus abdominalis muscle flaps was the treatment employed. Between these two stages of treatment, massive hemorrhage developed in seven patients (0.07%) from a tear of the anterior wall of the right ventricle (RV). Six patients survived. Temporary control of the bleeding was achieved with digital or full palm pressure control of the ventricular tear. This was followed by immediate repair in the operating room (OR). The only death was due to exsanguination in the intensive care unit. The other six patients were taken to the OR. The anterior RV was freed from the underside of the sternum and the RV tear repaired with or without the aid of femoral-femoral bypass. These six then had muscle flap wound closures at that time or shortly after. All six were hospital survivors and are currently alive. We believe that RV rupture results from the sternal edges pulling the anterior surface of the RV apart, since the RV is stuck to the underside of the sternum. This experience indicates that the RV must be freed in all cases during initial sternal debridement. Hopefully this simple maneuver will prevent this horrendous complication.
- Published
- 1996
- Full Text
- View/download PDF
7. Skeletal Muscle Ventricles in Circulation: Decreased Incidence of Rupture
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Thomas, G. A., Lu, H., Isoda, S., Hammond, R. L., Nakajima, H., Nakajima, H. O., and Stephenson, L. W.
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- 1996
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8. Using skeletal muscle to assist the heart.
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Hooper, T L and Stephenson, L W
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- 1991
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9. CAROTID ARTERY PUNCTURE WITH INTERNAL JUGULAR CANNULATION Using the Seldinger Technique
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Schwartz, A. J., primary, Jobes, D. R., additional, Greenhow, D. Eric, additional, Stephenson, L. W., additional, and Ellison, N., additional
- Published
- 1979
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10. Effects of nitroprusside and dopamine on pulmonary arterial vasculature in children after cardiac surgery.
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Stephenson, L W, primary, Edmunds, L H, additional, Raphaely, R, additional, Morrison, D F, additional, Hoffman, W S, additional, and Rubis, L J, additional
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- 1979
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11. Surgery using cardiopulmonary bypass in the elderly.
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Stephenson, L W, primary, MacVaugh, H, additional, and Edmunds, L H, additional
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- 1978
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12. Histochemical and fatigue characteristics of conditioned canine latissimus dorsi muscle.
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Mannion, J D, primary, Bitto, T, additional, Hammond, R L, additional, Rubinstein, N A, additional, and Stephenson, L W, additional
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- 1986
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13. The Blalock-Taussig anastomosis in infants younger than 1 week of age.
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Edmunds, L H, primary, Stephenson, L W, additional, and Gadzik, J P, additional
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- 1980
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14. Staged surgical management of tetralogy of Fallot in infants.
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Stephenson, L W, primary, Friedman, S, additional, and Edmunds, L H, additional
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- 1978
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15. Combined aortic and mitral valve replacement: changes in practice and prognosis.
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Stephenson, L W, primary, Edie, R N, additional, Harken, A H, additional, and Edmunds, L H, additional
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- 1984
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16. Power output of skeletal muscle ventricles in circulation: short-term studies.
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Mannion, J D, primary, Acker, M A, additional, Hammond, R L, additional, Faltemeyer, W, additional, Duckett, S, additional, and Stephenson, L W, additional
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- 1987
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17. BENTONITE IN THE UPPER CRETACEOUS OF NEW JERSEY
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Stephenson, L. W., primary
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- 1936
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18. Correlation of the Upper Cretaceous or Gulf series of the Gulf Coastal Plain
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Stephenson, L. W., primary
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- 1928
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19. Major marine transgressions and regressions and structural features of the Gulf Coastal Plain
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Stephenson, L. W., primary
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- 1928
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20. Skeletal Muscle Ventricles in the Pulmonary Circulation: Up to 16 Weeks' Experience
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Stephenson, L. W.
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- 1998
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21. As originally published in 1993: skeletal muscle ventricles: left ventricular apex to aorta configuration. Updated in 2001.
- Author
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Thomas GA and Stephenson LW
- Subjects
- Animals, Dogs, Heart Failure physiopathology, Humans, Prognosis, Cardiomyoplasty methods, Heart Failure surgery, Hemodynamics physiology, Postoperative Complications physiopathology
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- 2001
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22. Functional assessment of skeletal muscle ventricles after pumping for up to four years in circulation.
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Thomas GA, Hammond RL, Greer K, Lu H, Jarvis JC, Shortland AP, Pullan DM, Salmons S, and Stephenson LW
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- Animals, Dogs, Female, Follow-Up Studies, Graft Survival physiology, Heart Ventricles pathology, Heart Ventricles physiopathology, Postoperative Complications pathology, Ventricular Function, Left physiology, Cardiomyoplasty, Hemodynamics physiology, Myocardial Contraction physiology, Postoperative Complications physiopathology
- Abstract
Background: The successful treatment of cardiac failure by heart transplantation is severely limited by the shortage of donor organs, and alternative surgical approaches are needed. An experimental approach that holds considerable promise is the skeletal muscle ventricle (SMV), an auxiliary blood pump formed from a pedicled graft of latissimus dorsi muscle and connected to the circulation in a cardiac assist configuration. Adaptive transformation, or conditioning, by electrical stimulation enables the skeletal muscle to perform a significant proportion of cardiac work indefinitely without fatigue., Methods: In 10 dogs, SMVs were constructed from the latissimus dorsi muscle, lined internally with pericardium, and conditioned by electrical stimulation to induce fatigue resistant properties. The SMVs were connected to the descending thoracic aorta via two 12-mm Gore-Tex conduits and the aorta was ligated between the two grafts. The SMV was stimulated to contract during the diastolic phase of alternate cardiac cycles. The animals were monitored at regular intervals., Results: At initial hemodynamic assessment, SMV contraction augmented mean diastolic blood pressure by 24.6% (from 61 +/- 7 to 76 +/- 9 mm Hg). Presystolic pressure was reduced by 15% (from 60 +/- 8 to 51 +/- 7 mm Hg) after an assisted beat. Four animals died early, 1 from a presumed arrhythmia, and 3 during propranolol-induced hypotension. The other 6 animals survived for 273, 596, 672, 779, 969, 1,081, and 1,510 days. Diastolic augmentation was 27.4% at 1 year (93 +/- 9 vs 73 +/- 6 mm Hg; n = 5), 34.7% at 2 years (85 +/- 6 vs 63 +/- 7 mm Hg; n = 3), 21.2% (89 +/- 10 vs 73 +/- 8 mm Hg; n = 2) at 3 years, and 34.5% (78 vs 58 mm Hg; n = 1) after 4 years in circulation. After 4 years, the isolated SMV was able to maintain a pressure of over 80 mm Hg while ejecting fluid at 20 mL/s. No animal showed evidence of SMV rupture or thromboembolism., Conclusions: The SMVs in this study provided effective and stable hemodynamic assistance over an extended period of time. There was no evidence that the working pattern imposed on the muscular wall of the SMV compromised its viability. Areas of fibrofatty degeneration were suggestive of early damage that future protocols should seek to minimize.
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- 2000
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23. Power output of pericardium-lined skeletal muscle ventricles, left ventricular apex to aorta configuration: up to eight months in circulation.
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Thomas GA, Baciewicz FA Jr, Hammond RL, Greer KA, Lu H, Bastion S, Jindal P, and Stephenson LW
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- Animals, Assisted Circulation methods, Blood Flow Velocity, Cardiac Output, Disease Models, Animal, Dogs, Electric Stimulation, Follow-Up Studies, Heart Failure surgery, Heart Ventricles surgery, Aorta, Thoracic surgery, Heart-Assist Devices, Pericardium surgery, Skeletal Muscle Ventricle physiology, Ventricular Function
- Abstract
Objective: The purpose of this experiment was to evaluate the potential for a skeletal muscle ventricle connected to the circulation between the left ventricle and the aorta to provide effective, long-term cardiac assist., Methods: Skeletal muscle ventricles were constructed from the latissimus muscle in 10 dogs. After conditioning, the skeletal muscle ventricles were connected to the left ventricle and the aorta with 2 valved conduits. The skeletal muscle ventricle was programmed to contract during diastole., Results: At time of implantation, skeletal muscle ventricles stimulated at 33 Hz and in a 1:2 ratio with the heart significantly decreased left ventricular work by 56% (P <.01) and at 50 Hz by 65% (P <.01). At a 1:2 ratio, the power output of the skeletal muscle ventricles was 59% of left ventricular power output at 33 Hz (P <. 01) and 93% at 50 Hz (P <.01). Animals survived 7, 11, 16, 17, 72, 99, 115, 214, and 249 days. Three deaths were directly related to the skeletal muscle ventricle. One animal is alive at 228 days. In the animal that survived 249 days, skeletal muscle ventricle power output at 8 months with a 33 Hz stimulation frequency and a 1:2 contraction ratio was 57% of left ventricular power output and 82% at 50 Hz. At a 1:1 ratio, skeletal muscle ventricle power output was 97% and 173% of the left ventricle at 33 and 50 Hz, respectively., Conclusions: Left ventricular assist with a skeletal muscle ventricle connected between the left ventricle and the aorta is the most hemodynamically effective configuration we have tested and can maintain significant power output up to 8 months.
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- 1998
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24. As originally published in 1992: Skeletal muscle ventricles in the pulmonary circulation: up to 16 weeks' experience. Updated in 1998.
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Niinami H, Hooper TL, Hammond RL, Ruggiero R, Lu H, Spanta AD, Pochettino A, Colson M, and Stephenson LW
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- Animals, Disease Models, Animal, Dogs, Cardiomyoplasty, Skeletal Muscle Ventricle
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- 1998
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25. Skeletal muscle ventricles, left ventricular apex-to-aorta configuration. 1 to 11 weeks in circulation.
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Greer KA, Lu H, Spanta AD, Hammond RL, and Stephenson LW
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- Animals, Aorta, Thoracic physiopathology, Blood Pressure, Carotid Arteries physiopathology, Diastole, Dogs, Electric Stimulation, Femoral Artery physiopathology, Regional Blood Flow, Survival Analysis, Time Factors, Cardiomyoplasty methods, Ventricular Function, Left
- Abstract
Background: Skeletal muscle ventricles (SMVs) have been used in animals in a variety of configurations to provide circulatory assistance. Long-term survival and function have been demonstrated. Our laboratory recently obtained promising short-term hemodynamic data in a left ventricular apex-to-aorta model., Methods and Results: SMVs were constructed from the left latissimus dorsi muscle in five adult mongrel dogs. After a 3-week period of vascular delay and 5 to 7 weeks of electrical conditioning, valved conduits were used to connect the left ventricular apex to the SMV and the SMV to the descending aorta. The SMV was then stimulated to contract during cardiac diastole. Initial measurements showed a significant increase in the mean femoral diastolic pressure (62 +/- 6 versus 51 +/- 5 mm Hg, P < .05). There was also a decrease in the left ventricular tension-time index (11.5 +/- 2.5 versus 14.6 +/- 2.1 mm Hg.s, P < .05), indicating a decrease in the work requirement of the left ventricle. During SMV stimulation, the majority of flow (65%) was through the SMV circuit and was associated with reversal of flow in the proximal descending thoracic aorta. The longest-surviving animal survived 76 days, at which time pressure augmentation was still seen (mean femoral diastolic pressure, 63 +/- 0.9 versus 50 +/- 1.2 mm Hg, P < .05)., Conclusions: Survival beyond the acute setting is possible with this model. Diastolic pressure augmentation can be effectively maintained over time.
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- 1997
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26. Pericardium-lined skeletal muscle ventricles: up to two years' in-circulation experience.
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Thomas GA, Isoda S, Hammond RL, Lu H, Nakajima H, Nakajima HO, Greer K, Gilroy SJ, Salmons S, and Stephenson LW
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- Animals, Dogs, Electrophoresis, Polyacrylamide Gel, Female, Hemodynamics, Muscle, Skeletal chemistry, Pericardium transplantation, Time Factors, Transplantation, Autologous, Cardiomyoplasty mortality
- Abstract
Background: Skeletal muscle ventricles (SMVs) are autologous pumping chambers constructed from skeletal muscle. Skeletal muscle ventricular rupture and thromboembolism have complicated chronic models of this method of skeletal muscle cardiac assist., Methods: The SMVs were constructed from the latissimus dorsi muscle in 10 dogs. The inner surface of each SMV was lined with autologous pericardium harvested at the time of SMV construction. After a 3-week period of vascular delay and 6 weeks of electrical conditioning to convert the muscle to a fatigue-resistant state, SMVs were connected to the descending thoracic aorta and stimulated to contract during cardiac diastole., Results: Initial hemodynamics revealed that SMV contraction at 33 Hz increased diastolic pressure 24.7% (60.8 +/- 7.3 mm Hg versus 80.3 +/- 8.8 mm Hg). Skeletal muscle ventricle relaxation decreased presystolic pressure 14.4% (59.9 +/- 7.7 mm Hg versus 51.3 +/- 7.5 mm Hg) and decreased peak systolic pressure 4.1% (90.2 +/- 7.3 mm Hg versus 86.5 +/- 5.8 mm Hg). Hemodynamics were assessed at 1 to 2 weeks, then at 1, 2, 3, and 6 months, and at 6-month intervals thereafter. Hemodynamic performance remained stable for the duration of this study. After 2 years of pumping continuously in circulation, SMV contraction resulted in a 34.8% augmentation of diastolic pressure (63.6 +/- 6.6 mm Hg versus 85.3 +/- 6.4 mm Hg), a 17.2% decrease in presystolic pressure (54.7 +/- 3.73 mm Hg versus 45.3 +/- 4.1 mm Hg), and a 4.2% decrease in peak systolic pressure (95.3 +/- 10.4 mm Hg versus 91.3 +/- 12.3 mm Hg). Three dogs survived to 2 years with the SMVs in circulation. No animal showed evidence of thromboembolism during serial echocardiography or at autopsy and no SMVs ruptured., Conclusions: These data demonstrate that SMVs can provide effective hemodynamic assist over an extended period without specific complications related to the SMVs.
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- 1996
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27. Endothelial cell-lined skeletal muscle ventricles in circulation.
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Thomas GA, Lelkes PI, Isoda S, Chick D, Lu H, Hammond RL, Nakajima H, Nakajima H, Walters HL 3rd, and Stephenson LW
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- Animals, Cell Transplantation, Cells, Cultured, Dogs, Endothelium, Vascular ultrastructure, Hemodynamics, Muscle, Skeletal physiology, Cardiomyoplasty methods, Endothelium, Vascular cytology, Ventricular Function
- Abstract
Skeletal muscle ventricles were constructed from the latissimus dorsi in six dogs by wrapping the muscle around a polypropylene mandrel. Jugular vein endothelial cells were harvested enzymatically and grown in tissue culture. After 3 weeks of vascular delay and 4 weeks of electrical conditioning, five skeletal muscle ventricles were seeded with 5 to 8 x 10(6) autologous endothelial cells by percutaneous injection of a cellular suspension into the lumen of the skeletal muscle ventricle; one skeletal muscle ventricle was injected with culture medium alone as an unseeded control. The autologous endothelial cells were all prelabeled with a lipid-bound cellular marker, PKH-26. After an additional 4 weeks of electrical conditioning, the mandrels were removed and the skeletal muscle ventricles were connected to the descending thoracic aorta and activated to contract during cardiac diastole at a 1:2 ratio with the heart. After 3 hours of continuous pumping, mean diastolic pressure was increased by 35% (58 +/- 7 versus 78 +/- 6 mm Hg, p < 0.05). At this time, the skeletal muscle ventricles were excised for histologic examination. Sections stained with hematoxylin and eosin revealed a continuous cellular layer lining the skeletal muscle ventricle; no cells were present on the lumen of the control skeletal muscle ventricle. All seeded skeletal muscle ventricles exhibited fluorescence as a result of the PKH-26 cellular marker. Immunofluorescent staining with antibodies to von Willebrand factor and ultrastructural analysis with an electron microscope confirmed the endothelial character of these cells lining the lumen of the skeletal muscle ventricles. The ability to create endothelial cell-lined muscular pumping chambers holds important implications for the resolution of thrombotic events in cardiac assist devices as well as toward the clinical application of skeletal muscle ventricles.
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- 1995
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28. Pericardium-lined skeletal muscle ventricles in circulation up to 589 days.
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Thomas GA, Lu H, Isoda S, Hammond RL, Nakajima H, Nakajima HO, Colson M, and Stephenson LW
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- Animals, Cardiac Output, Dogs, Electric Stimulation, Hemodynamics, Muscle, Skeletal physiology, Myocardium metabolism, Oxygen Consumption, Time Factors, Ventricular Function, Ventricular Function, Left, Bioprosthesis, Counterpulsation methods, Heart Ventricles, Muscle, Skeletal transplantation
- Abstract
Skeletal muscle ventricles (SMVs) were constructed from the latissimus dorsi muscle in 15 beagles. The animals were divided into two groups based on modifications in the SMV construction: group I consisted of 5 animals and group II of 10 animals. After a 3-week vascular delay and 6 to 8 weeks of 2-Hz electrical conditioning, the SMVs were connected to the thoracic aorta. In group I, counterpulsation at 33 Hz resulted in an initial 24.4% augmentation of the mean diastolic pressure, a 27.1% decrease in the presystolic pressure, and a 15.9% increase in the endocardial viability ratio. In group II, the mean diastolic pressure rose by 24.7%, the presystolic pressure decreased by 14.3%, and the endocardial viability ratio increased by 24.5%. During propranolol-induced heart failure, the percentage increase in the mean diastolic pressure was improved (12.9% before propranolol infusion versus 27.6% during propranolol infusion), as was the percentage increase in the endocardial viability ratio (11.2% versus 28.7%). Under low cardiac output conditions, SMV contraction resulted in small but statistically significant increases in the total cardiac output (4.3% at 33 Hz, 7.6% at 85 Hz). One animal in group I survived for 589 days with a functioning SMV before progressive dilation of the SMV (impending rupture) developed. Delayed rupture of the SMV sewing ring anastomosis occurred in 2 dogs. Five animals in group II are all alive, with functioning SMVs in the circulation for 377 to 464 days. No animals in group II had rupture of their SMV or showed evidence of thrombus formation.
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- 1994
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29. Detection of canine allograft lung rejection by pulmonary lymphoscintigraphy.
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Ruggiero R, Fietsam R Jr, Thomas GA, Muz J, Farris RH, Kowal TA, Myles JL, Stephenson LW, and Baciewicz FA Jr
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- Acute Disease, Animals, Dogs, Graft Rejection physiopathology, Immunosuppression Therapy, Lung diagnostic imaging, Lung physiology, Lung physiopathology, Lung Transplantation diagnostic imaging, Lymph Nodes physiology, Lymph Nodes physiopathology, Lymphatic System physiopathology, Lymphoscintigraphy, Mediastinum physiopathology, Transplantation, Homologous, Graft Rejection diagnostic imaging, Lung Transplantation physiology, Lymph Nodes diagnostic imaging, Lymphatic System physiology, Mediastinum diagnostic imaging
- Abstract
We previously demonstrated that lymphoscintigraphy could be used to study pulmonary lymphatic flow. Radiocolloids, high-molecular-weight proteins tagged with radioactive markers, are injected percutaneously in the periphery of the lung. These molecules enter the lymph, are transported via lymphatic channels, and concentrate in the tributary hilar and mediastinal lymph nodes, where they can be visualized by nuclear scan. The goal of this study was to determine whether pulmonary lymphoscintigraphy could be used to detect allograft rejection after lung transplantation. Thirteen mongrel dogs underwent left lung allotransplantation. Cyclosporine 15 mg/kg per day and azathioprine 1 mg/kg per day were given orally for postoperative immunosuppression. Lymphoscintigraphic studies were obtained 1 week after the operation and then at weekly intervals. In five dogs (group A), immunosuppression was continued until the animal died or was put to death 6 weeks later. Lymphoscintigraphy demonstrated reestablishment of lymphatic drainage between the lung graft and the mediastinum in all the animals 2 to 4 weeks after transplantation. In eight dogs (group B), immunosuppression was discontinued after reestablishment of graft lymphatic drainage was documented by two consecutive lymphoscintigraphic studies. The dogs continued to be studied with weekly scans. In group B, lymphatic drainage from the lung graft to the mediastinum disappeared 1 to 4 weeks after immunosuppression was stopped. Rejection was diagnosed clinically and confirmed histologically with open lung biopsies and/or autopsies in all animals. This study shows that canine allograft lung rejection is associated with disappearance of lymphatic drainage from lung graft to mediastinum, which can be documented by pulmonary lymphoscintigraphy, a minimally invasive technique that can be easily repeated. Pulmonary lymphoscintigraphy may be useful for early detection of lung allograft rejection.
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- 1994
30. Invited letter concerning: Dynamic cardiomyoplasty acutely impairs left ventricular diastolic function.
- Author
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Stephenson LW
- Subjects
- Animals, Cardiac Surgical Procedures adverse effects, Diastole, Dogs, Heart Failure physiopathology, Humans, Heart Failure surgery, Muscles transplantation, Surgical Flaps adverse effects, Ventricular Function, Left physiology
- Published
- 1993
31. Reestablishment of lymphatic drainage after canine lung transplantation.
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Ruggiero R, Muz J, Fietsam R Jr, Thomas GA, Welsh RJ, Miller JE, Stephenson LW, and Baciewicz FA Jr
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- Animals, Antimony, Colloids, Dogs, Lung Transplantation diagnostic imaging, Lymphoscintigraphy, Regeneration, Technetium, Lung Transplantation physiology, Lymphatic System physiology, Technetium Compounds
- Abstract
The technique of pulmonary lymphoscintigraphy was used to evaluate pulmonary lymphatic flow and to assess reestablishment of lymphatic drainage after lung transplantation. A first group of six control dogs underwent percutaneous transthoracic injection of a radiocolloid into the periphery of the left upper and lower lobes. Radiocolloids are large molecules tagged with radioisotopes that are absorbed only through lymph and are concentrated in tributary lymph nodes. Twenty-four hours after injection the dogs underwent scintigraphic studies of the chest and upper part of the abdomen. Mediastinal lymph nodes were visualized in all animals. A second group of four dogs underwent partial reimplantation of the native left lung, with interruption of all lymphatic connections between the lung and mediastinum. Lymphoscintigraphic studies of the left lung were obtained on the third postoperative day and then weekly for 4 weeks. Three of the four dogs in this group did not have visible mediastinal nodes 3 days after the operation. Nodes were visualized in all animals at 1 week and at all following studies. A third group of five dogs were subjected to left lung allotransplantation by means of standard surgical techniques, as well as immunosuppression. The animals were studied with radiocolloid injections and lung lymphoscintigraphy at weekly intervals for 6 weeks. Mediastinal nodes were visualized for the first time 2 to 4 weeks after the operation and at every subsequent study. We conclude that lung lymphoscintigraphy is a reliable technique for the study of pulmonary lymphatic flow. This experiment demonstrates that lymphatic drainage after lung transplantation is reestablished as early as the second postoperative week.
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- 1993
32. Skeletal muscle ventricles: left ventricular apex to aorta configuration.
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Lu H, Fietsam R Jr, Hammond RL, Nakajima H, Mocek FW, Thomas GA, Ruggiero R, Nakajima H, Colson M, and Stephenson LW
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- Animals, Aorta physiopathology, Bioprosthesis, Blood Pressure physiology, Blood Vessel Prosthesis, Dogs, Electrocardiography, Heart Valve Prosthesis, Heart Ventricles physiopathology, Myocardial Contraction physiology, Pacemaker, Artificial, Polytetrafluoroethylene, Stroke Volume physiology, Suture Techniques, Aorta surgery, Heart Ventricles surgery, Hemodynamics physiology, Muscles transplantation, Ventricular Function, Left physiology
- Abstract
Skeletal muscle ventricles (SMVs) were constructed from the latissimus dorsi muscle in 6 dogs. After 3 weeks of vascular delay followed by 6 weeks of 2-Hz continuous electrical conditioning, a valved conduit was placed between the left ventricular apex and the SMV and a second valved conduit, between the SMV and the aorta. The SMV was stimulated to contract during diastole at a 1:2 ratio with the heart. The SMV pumped 47% of the systemic blood flow initially (0.73 +/- 0.23 versus 1.54 +/- 0.42 L/min) and 40% after 3 hours. Skeletal muscle ventricle stimulation resulted in a 58% increase in mean diastolic pressure initially (52 +/- 9 to 82 +/- 11 mm Hg; p < 0.05) and a 73% increase (45 +/- 7 to 78 +/- 8 mm Hg) after 3 hours of continuous pumping. This was associated with a 68% increase in the endocardial viability ratio initially and a 63% increase at 3 hours. The systolic tension-time index decreased by 26% initially and 25% at 3 hours. This study indicates that the SMV configuration of left ventricular apex to aorta may be particularly suitable for left ventricular assist.
- Published
- 1993
- Full Text
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33. Update on skeletal muscle ventricles as aortic diastolic counterpulsators.
- Author
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Nakajima H, Thomas GA, Nakajima HO, Hammond RL, Fietsam R Jr, Mocek FW, Hooper TL, Lu H, Spanta AD, and Stephenson LW
- Subjects
- Animals, Assisted Circulation, Diastole, Dogs, Electrocardiography, Hemodynamics drug effects, Muscle Contraction, Postoperative Complications, Propranolol pharmacology, Aorta, Thoracic, Cardiac Surgical Procedures, Surgical Flaps
- Abstract
Skeletal muscle ventricles are constructed from canine latissimus dorsi muscle. These skeletal muscle ventricles can be placed subcutaneously on the chest wall or inside the chest cavity. Skeletal muscle ventricles are connected to the descending thoracic aorta and activated to pump blood as aortic diastolic counterpulsators. The skeletal muscle ventricle in 1 animal pumped blood in the circulation for 27 months. Skeletal muscle ventricles can also function effectively under the condition of low cardiac output. Although thrombus has been detected in some skeletal muscle ventricles, thromboembolism to distal organs has been detected only rarely during the past few years. This research appears promising; however, skeletal muscle ventricle rupture remains a problem and currently accounts for about 30% of the mortality in the long-term experiments. It occurs at the site between the skeletal muscle ventricle outlet and the Dacron sewing ring that is necessary to connect conduits from the skeletal muscle ventricle to the animal's circulation. We believe that skeletal muscle ventricle rupture is likely to be a solvable problem. Once a solution has been found, skeletal muscle ventricles may be ready for clinical use in patients with chronic congestive heart failure.
- Published
- 1993
34. Skeletal muscle ventricles as left atrial-aortic pumps: short-term studies.
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Hooper TL, Niinami H, Hammond RL, Lu H, Ruggiero R, Pochettino A, and Stephenson LW
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- Animals, Aorta surgery, Dogs, Electrocardiography, Female, Heart Atria surgery, Hemodynamics, Methods, Muscle Contraction, Pacemaker, Artificial, Heart Ventricles surgery, Muscles transplantation
- Abstract
In 5 dogs, skeletal muscle ventricles (SMVs) were constructed from the latissimus dorsi muscle and placed in the left hemithorax. After a 3-week vascular delay period, SMVs were electrically preconditioned with 2-Hz stimulation for 6 weeks. At a second operation, SMVs were connected between the left atrium and thoracic aorta by afferent and efferent aortic root homografts, and stimulated to contract in a 1:2 diastolic mode. At a mean left atrial pressure of 12.4 +/- 1.3 mm Hg and a burst stimulation frequency of 33 Hz, SMV stroke volume was initially 43% of that of the native left ventricle, achieving a flow equivalent to 21% of cardiac output (194 +/- 38 versus 902 +/- 85 mL/min). At 50-Hz stimulation, this figure rose to 27% (246 +/- 41 mL/min; p less than 0.05). Skeletal muscle ventricle power output (the product of stroke work and contraction rate) at 33 Hz was 0.016 +/- 0.003 W, increasing to 0.024 +/- 0.004 W at 50 Hz (p less than 0.05), corresponding to 14% and 22%, respectively, of left ventricular power output (0.11 +/- 0.012 W). After 4 hours of continuous pumping, four of the SMVs were still generating flows of more than 70% of starting values and more than 60% of initial power output. This study demonstrates that SMVs can function in the systemic circulation at physiologic left atrial preloads.
- Published
- 1992
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- View/download PDF
35. Skeletal muscle ventricles with improved thromboresistance: 28 weeks in circulation.
- Author
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Pochettino A, Mocek FW, Lu H, Hammond RL, Spanta AD, Hooper TL, Niinami H, Ruggiero R, Colson M, and Stephenson LW
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- Animals, Dogs, Time Factors, Heart Ventricles surgery, Hemodynamics, Muscles surgery, Surgical Flaps
- Abstract
Skeletal muscle ventricles (SMVs) were constructed from the left latissimus dorsi in 22 mongrel dogs. The configuration of these SMVs was different from those previously reported. The animals were divided into two groups: group A (n = 11) SMVs rested for 10 weeks after construction; group B (n = 11) SMVs rested for 18 weeks. At the end of the delay period, SMVs were tested in vivo with a mock circulation device. The SMVs in group B developed stroke work greater than those in group A. After acute testing, SMVs (n = 12) were connected to the descending thoracic aorta and stimulated to contract during diastole. Aortic diastolic counterpulsation was achieved in all dogs, with 9 animals surviving from 1 to beyond 28 weeks. In all of the dogs surviving 1 week or more, the SMVs remained free of thrombus. Aspirin was used as the only antithrombotic agent. Skeletal muscle ventricles in this study were able to develop stroke work similar to that previously reported, intermediate between that of the right and left ventricular stroke work, with a significantly decreased incidence of thromboembolism.
- Published
- 1992
- Full Text
- View/download PDF
36. Skeletal muscle ventricles in the pulmonary circulation: up to 16 weeks' experience.
- Author
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Niinami H, Hooper TL, Hammond RL, Ruggiero R, Lu H, Spanta AD, Pochettino A, Colson M, and Stephenson LW
- Subjects
- Anastomosis, Surgical, Animals, Blood Pressure physiology, Cardiac Output physiology, Dogs, Electric Stimulation, Muscles pathology, Pulmonary Artery physiology, Pulmonary Artery surgery, Stroke Volume physiology, Adaptation, Physiological physiology, Assisted Circulation methods, Muscles physiology, Muscles transplantation, Ventricular Function
- Abstract
Skeletal muscle ventricles (SMVs) were constructed from the right latissimus dorsi muscle of 8 mongrel dogs. After a 3-week vascular delay period, each SMV was electrically preconditioned with 2-Hz continuous stimulation of the thoracodorsal nerve for 6 weeks. A porcine-valved conduit was then anastomosed between the right ventricle and the SMV, with a second valved conduit connecting the SMV to the main pulmonary artery. The pulmonary artery was then ligated proximal to the conduit. The SMVs were stimulated to contract in 1:2 diastolic mode with a 33-Hz burst frequency. Effective right ventricular assist was achieved in all dogs. Cardiac output increased by 22.6% (1,799 +/- 97 versus 1,467 +/- 84 mL/min; p less than 0.001), systemic systolic arterial pressure by 9.3% (90.1 +/- 3.5 versus 82.4 +/- 3.9 mm Hg; p less than 0.005), and peak pulmonary artery pressure by 31.8% (27.8 +/- 2.0 versus 21.1 +/- 1.7 mm Hg; p less than 0.001) at the initiation of this study. In 6 dogs, effective right heart assist was sustained for periods of between 1 week and 12 weeks. Two dogs survived for longer than 3 months, though with evidence of deteriorating SMV function. These results demonstrate the feasibility of providing sustained right ventricular assist using this modified "Rastelli-SMV" configuration, which obviates the limitations imposed by low right atrial preload.
- Published
- 1992
- Full Text
- View/download PDF
37. Assisted circulation using skeletal muscle.
- Author
-
Hooper TL and Stephenson LW
- Subjects
- Animals, Dogs, Electric Stimulation, Humans, Treatment Outcome, Assisted Circulation methods, Muscles transplantation
- Published
- 1992
38. Autogenously lined skeletal muscle ventricles in circulation. Up to nine months' experience.
- Author
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Anderson DR, Pochettino A, Hammond RL, Hohenhaus E, Spanta AD, Bridges CR Jr, Lavine S, Bhan RD, Colson M, and Stephenson LW
- Subjects
- Animals, Aorta, Thoracic surgery, Blood Flow Velocity, Blood Pressure, Dogs, Electric Stimulation, Electrocardiography, Muscle Contraction, Muscles physiology, Pericardium transplantation, Pleura transplantation, Transplantation, Autologous, Counterpulsation, Heart Ventricles surgery, Muscles transplantation
- Abstract
Skeletal muscle ventricles were constructed in fifteen dogs. After a delay period of 4 weeks the skeletal muscle ventricles were connected to the descending thoracic aorta with a polytetrafluoroethylene bifurcation graft (Gore-Tex bifurcation graft, W.L. Gore & Associates, Inc., Elkton, Md.). The aorta was ligated between the two limbs of the graft so that there was obligatory blood flow through the skeletal muscle ventricle. Nine skeletal muscle ventricles were lined with autogenously derived tissue, either pleura or pericardium, whereas six had no specific lining other than an induced fibrous reaction. The skeletal muscle ventricles were activated to contract during cardiac diastole. Aortic diastolic counterpulsation was achieved in all dogs, with ten surviving from 1 week to beyond 9 months. Thrombus eventually developed in all but three of the skeletal muscle ventricles, but no dog had clinical evidence of thromboemboli. The three thrombus-free skeletal muscle ventricles were lined with pleura, including the animal surviving beyond 9 months. These results indicate that canine skeletal muscle can provide aortic diastolic counterpulsation for 9 months without clinically apparent thromboembolic complications.
- Published
- 1991
39. Skeletal muscle ventricles for total heart replacement.
- Author
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Pochettino A, Spanta AD, Hammond RL, Anderson DR, Bridges CR Jr, Samet P, Niinami H, Hohenhaus E, Salmons S, and Stephenson LW
- Subjects
- Adaptation, Physiological physiology, Animals, Dogs, Electric Stimulation Therapy, Heart physiology, Myocardium pathology, Physical Endurance, Stroke Volume, Cardiac Surgical Procedures methods, Muscles transplantation
- Abstract
Skeletal muscle ventricles (SMV) were constructed from canine left latissimus dorsi muscle. The animals were divided into three groups: group A (n = 5), SMVs rested 4 weeks without electrical conditioning; group B (n = 6), SMVs rested 4 weeks and then electrically conditioned for 6 weeks; group C (n = 5), SMVs rested 18 weeks without electrical conditioning. At the end of each protocol, the SMVs were acutely tested by connecting them to a mock-circulation device. The SMVs in group C developed stroke work at physiologic preloads superior to any previously reported, as high as 194% of left ventricular stroke work at afterloads of 80 mmHg. The SMVs in group B developed work outputs equivalent to 53% of the left ventricle, which is still more than four times that of the right ventricle. The results show that it is possible to harvest sufficient work from skeletal muscle ventricles to fully replace cardiac function at physiologic preloads.
- Published
- 1990
- Full Text
- View/download PDF
40. Skeletal muscle grafts applied to the heart. A word of caution.
- Author
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Anderson WA, Andersen JS, Acker MA, Hammond RL, Chin AJ, Douglas PS, Khalafalla AS, Salmons S, and Stephenson LW
- Subjects
- Animals, Aorta physiopathology, Blood Pressure, Cardiopulmonary Bypass, Dogs, Echocardiography, Electric Stimulation, Heart physiopathology, Hemodynamics, Histocytochemistry, Muscle Contraction, Muscles physiology, Myocardium pathology, Ventricular Fibrillation physiopathology, Heart physiology, Muscles transplantation
- Abstract
Latissimus dorsi pedicle grafts (LDPGs) were wrapped around the heart in eight dogs. In four dogs, the LDPGs were stimulated chronically; the remaining four dogs served as unstimulated controls. Right-sided cardiac filling pressures were normal in all dogs when measured 4 months after graft application. Mean tension generated by the viable LDPGs was 153 +/- 49.9 g. LDPGs contracting in synchrony with the heart did not increase cardiac output. In one dog, the aortic pressure changed from 140/100 to 155/85 mm Hg during synchronous contraction of the LDPG. Three dogs were placed on cardiopulmonary bypass, and their hearts were placed in fibrillation. The LDPGs were then stimulated at a burst frequency of 85 Hz and contracted vigorously. Under these conditions, the left ventricular pressure increased by an average of 15 mm Hg with each LDPG contraction; however, the mean aortic pressure was virtually unchanged. Left ventricular and aortic pressures of 125/20 and 125/65 mm Hg, respectively, could be obtained with manual compression of the fibrillating heart. This study indicates that although LDPGs can be made to contract chronically and in synchrony with the heart, they do not necessarily augment left ventricular performance.
- Published
- 1988
41. External stent for repair of secondary tracheomalacia.
- Author
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Johnston MR, Loeber N, Hillyer P, Stephenson LW, and Edmunds LH Jr
- Subjects
- Airway Resistance, Animals, Cartilage Diseases physiopathology, Child, Preschool, Female, Functional Residual Capacity, Humans, Infant, Male, Swine, Tracheal Diseases physiopathology, Cartilage Diseases therapy, Disease Models, Animal, Prostheses and Implants, Tracheal Diseases therapy
- Abstract
Tracheomalacia was created in anesthetized piglets by submucosal resection of 3 to 5 tracheal cartilages. Measurements of airway pressure and flow showed that expiratory airway resistance is maximal at low lung volumes and is significantly increased by creation of the malacic segment. Cervical flexion increases expiratory airway resistance, whereas hyperextension of the neck reduces resistance toward normal. External stenting of the malacic segment reduces expiratory airway resistance, and the combination of external stenting and hyperextension restores airway resistance to normal except at low lung volume. Two patients with secondary tracheomalacia required tracheostomy and could not be decannulated after the indication for the tracheostomy was corrected. Both were successfully decannulated after external stenting of the malacic segment with rib grafts. Postoperative measurements of expiratory pulmonary resistance show a marked decrease from preoperative measurements. External stenting of symptomatic tracheomalacia reduces expiratory airway resistance by supporting and stretching the malacic segment and is preferable to prolonged internal stenting or tracheal resection.
- Published
- 1980
- Full Text
- View/download PDF
42. Platelet function during cardiac operation: comparison of membrane and bubble oxygenators.
- Author
-
Edmunds LH Jr, Ellison N, Colman RW, Niewiarowski S, Rao AK, Addonizio VP Jr, Stephenson LW, and Edie RN
- Subjects
- Adenosine Diphosphate analysis, Adenosine Triphosphate analysis, Blood Platelets analysis, Humans, Middle Aged, Oxygenators, Membrane, Platelet Count, Platelet Factor 4 analysis, Blood Platelets physiology, Cardiopulmonary Bypass, Oxygenators
- Abstract
The effects of cardiopulmonary bypass with bubble and membrane oxygenator systems on platelet function were studied in 26 patients who had elective coronary arterial bypass grafts. Fourteen patients were perfused with spiral coil membrane oxygenator systems, 12 with bubble oxygenator systems. During and after bypass, platelet counts decreased in both groups; however, when corrected for dilution, platelet counts did not change significantly in patients perfused with membrane oxygenators and increased slightly but significantly in those perfused with membrane oxygenators and increased slightly but significantly in those perfused with bubble oxygenator systems. During and 1 hour after bypass, the concentration of adenosine diphosphate (ADP) required to cause complete aggregation increased in both groups. Plasma low affinity platelet factor 4 (LA-PF4) increased significantly during and after bypass in both groups. However, the concentration of platelet adenine nucleotides and LA-PF4, measured only in patients perfused with membrane oxygenator systems, did not change. Bleeding times increased postoperatively in both groups and 18 hour blood losses were similar. Cardiopulmonary bypass with membrane and bubble oxygenator systems causes qualitatively similar losses in sensitivity to ADP and similar increases in bleeding times. The mechanism by which platelets are altered during cardiopulmonary bypass in obscure but is not due to partial depletion of granule contents in patients perfused with membrane oxygenators.
- Published
- 1982
43. Skeletal muscle as the potential power source for a cardiovascular pump: assessment in vivo.
- Author
-
Acker MA, Hammond RL, Mannion JD, Salmons S, and Stephenson LW
- Subjects
- Adenosine Triphosphatases metabolism, Animals, Blood Circulation, Blood Pressure, Dogs, Kinetics, Models, Biological, Muscles enzymology, Myosins metabolism, Cardiovascular Physiological Phenomena, Muscles physiology
- Abstract
Skeletal muscle ventricles (SMVs) were constructed from canine latissimus dorsi and connected to a totally implantable mock circulation device. The SMVs, stimulated by an implantable pulse generator, pumped continuously for up to 8 weeks in free-running beagle dogs. Systolic pressures produced by the SMVs, initially of 139 +/- 7.2 mmHg and after 1 month of continuous pumping of 107 +/- 7 mmHg, were comparable to normal physiologic pressures in the adult beagles (114 +/- 21 mmHg). After 2 weeks of continuous pumping, the mean stroke work of the SMVs was 0.4 X 10(6) ergs, a performance that compares favorably with the animal's cardiac ventricles. This study shows that canine skeletal muscle which has not received prior training or electrical conditioning can perform sustained work at the high levels needed for an auxiliary cardiovascular pump. It might be possible eventually to use such muscle pumps in humans to assist the failing circulation and to provide support in children with certain types of congenital heart defects.
- Published
- 1987
- Full Text
- View/download PDF
44. Comparison of effects of prostaglandin E1 and nitroprusside on pulmonary vascular resistance in children after open-heart surgery.
- Author
-
Rubis LJ, Stephenson LW, Johnston MR, Nagaraj S, and Edmunds LH Jr
- Subjects
- Adolescent, Alprostadil, Blood Pressure drug effects, Cardiac Output drug effects, Child, Child, Preschool, Female, Heart Rate drug effects, Humans, Infant, Male, Postoperative Care, Prostaglandins E adverse effects, Ferricyanides therapeutic use, Heart Defects, Congenital surgery, Nitroprusside therapeutic use, Prostaglandins E therapeutic use, Pulmonary Artery drug effects, Pulmonary Veins drug effects, Vascular Resistance drug effects
- Abstract
Prostaglandin E1 (PGE1) is a vasodilator. Because the drug is metabolized by lung, we postulated a selective effect on pulmonary vasculature. Twenty-six patients aged 3 months to 16 year (mean, 6.5 years) were studied after repair of atrial septal defect (5), ventricular septal defect (10), tetralogy of Fallot (3), and other lesions (8). Fourteen patients also received nitroprusside. PGE1 (0.1 to 1.0 micrograms/kg/min) or nitroprusside (0.59 to 8.7 micrograms/kg/min) was infused through a central venous catheter until mean pulmonary or mean systemic arteria pressure decreases at least 10%. Prostaglandin E1 and nitroprusside both decreased mean systemic arterial pressure and systemic vascular resistance (P less than 0.05). Although both drugs caused an average decrease in pulmonary arterial pressure and resistance, nitroprusside produced a more consistent response. Side-effects limited the use of PGE1 in 5 patients. PGE1 is an effective vasodilator and has advantages for some patients, but it does not produce selective vasodilation of pulmonary vessels.
- Published
- 1981
- Full Text
- View/download PDF
45. Pneumothorax during positive-pressure mechanical ventilation.
- Author
-
Bitto T, Mannion JD, Stephenson LW, Hammond R, Lanken PN, Miller W, Geer RT, and Wagner HR
- Subjects
- Animals, Blood Gas Analysis, Blood Pressure, Cardiac Output, Heart Rate, Lung Volume Measurements, Male, Pneumothorax physiopathology, Sheep, Stroke Volume, Hemodynamics, Pneumothorax etiology, Positive-Pressure Respiration adverse effects, Respiration
- Abstract
The hemodynamic and respiratory effects of unilateral pneumothorax were studied during positive-pressure mechanical ventilation in five sheep. The sheep were anesthetized, intubated, and placed on mechanical ventilation with positive end-expiratory pressure (5 cm H2O). After baseline studies, including chest roentgenograms, were taken, increments of air were injected into the right pleural cavity. Measurements were repeated at pneumothoraces of 500, 1,000, and 1,500 ml. There was a steady fall in cardiac output (p less than 0.02) at pneumothoraces of 1,000 and 1,500 ml. The decrease in cardiac stroke volume paralleled that of cardiac output. Heart rate rose (p less than 0.05) at a pneumothorax of 1,500 ml. There appeared to be a linear relationship between the percent increase in pneumothorax as estimated by roentgenogram and the percent fall in cardiac output (r = 0.991). There was a steady rise in mean pulmonary arterial, pulmonary arterial capillary wedge, superior vena caval, and inferior vena caval pressures, although the changes in inferior vena caval pressure were not statistically different from baseline. Peak airway pressure increased from baseline at pneumothoraces of 1,000 and 1,500 ml. Both right and left end-expiratory intrapleural pressures increased and were statistically different (p less than 0.01) from baseline. However, there was a substantially greater rise in right intrapleural pressure than left. Arterial oxygen tension remained physiological throughout the study. This study indicates that cardiac output decreases as the amount of pneumothorax increases in sheep during mechanical ventilation. This study also demonstrates that, during positive-pressure mechanical ventilation, a relatively benign-appearing pneumothorax by chest roentgenogram may be associated with a significantly depressed cardiac output. In addition, arterial oxygen tension may not be useful in predicting the onset of pneumothorax during mechanical ventilation.
- Published
- 1985
46. Propranolol for prevention of postoperative cardiac arrhythmias: a randomized study.
- Author
-
Stephenson LW, MacVaugh H 3rd, Tomasello DN, and Josephson ME
- Subjects
- Female, Humans, Male, Middle Aged, Propranolol administration & dosage, Random Allocation, Arrhythmias, Cardiac prevention & control, Coronary Artery Bypass, Postoperative Complications prevention & control, Propranolol therapeutic use
- Abstract
Two hundred twenty-three patients were randomly selected to receive propranolol, 10 mg orally every 6 hours, or to serve as controls after coronary artery bypass grafting. The study began at the time of discharge from the intensive care unit. Patients were ineligible if they had cardiac arrhythmias while in the intensive care unit, low cardiac output requiring catecholamine support, or bradycardia requiring a pacemaker. In the control group, cardiac arrhythmias for which treatment was necessary developed in 31 of 136 patients (23%), atrial fibrillation or flutter in 24 patients (18%), and ventricular arrhythmias in 7 (5%). In the group receiving propranolol, cardiac arrhythmias requiring treatment developed in 9 of 87 patients (10%), atrial fibrillation or flutter in 7 (8%), and ventricular arrhythmias in 2 (2%). The difference in frequency with which cardiac arrhythmias occurred between the two groups is significantly different (p less than 0.05). We conclude that propranolol is effective in the prevention of cardiac arrhythmias following coronary artery bypass grafting.
- Published
- 1980
- Full Text
- View/download PDF
47. Subclavian--left coronary artery anastomosis (Meyer operation) for anomalous origin of the left coronary artery from the pulmonary artery.
- Author
-
Stephenson LW, Edmunds LH Jr, Friedman S, Meijboom E, Gewitz M, and Weinberg P
- Subjects
- Child, Preschool, Female, Follow-Up Studies, Humans, Infant, Male, Methods, Pulmonary Artery surgery, Coronary Vessel Anomalies surgery, Coronary Vessels surgery, Pulmonary Artery abnormalities, Subclavian Artery surgery
- Abstract
Six patients, ages 2--76 months, had subclavian--coronary artery anastomosis (the Meyer operation) through a left thoracotomy without cardiopulmonary bypass for anomalous origin of the left coronary artery. Five of the six had congestive heart failure and ischemic abnormalities on the ECG. All six had cardiomegaly by chest x-ray. Preoperative left ventricular rejection reactions averaged 0.46 +/- 0.171. In three patients in whom peak systolic pressure was measured in the left coronary artery at operation, pressure increased by a mean of 26 mm Hg when the anastomosis was unclamped. One patient died. Five patients are alive 8--92 months postoperatively and four of the five anastomoses were patent at postoperative cardiac catheterization. Postoperative ECGs were normal or showed reduced T-wave abnormalities in all patients, and heart size by chest x-ray has decreased or is normal. Postoperative ejection fractions increased by a mean of 0.12 in four of the five patients (p = 0.01). On patient had a normal ejection fraction preoperatively and it remained unchanged postoperatively. No patient receives cardiac medications or is symptomatic at late follow-up. The Meyer operation can be performed at an early age, establishes a two-coronary-artery system, has growth potential, requires one vascular anastomosis, and in this series, resulted in reversal of left ventricular ischemic changes and improvement in left ventricular contractility.
- Published
- 1981
48. Functional right-heart replacement with skeletal muscle ventricles.
- Author
-
Bridges CR Jr, Hammond RL, Dimeo F, Anderson WA, and Stephenson LW
- Subjects
- Animals, Coronary Circulation physiology, Dogs, Electrocardiography, Heart-Assist Devices, Muscle Contraction physiology, Muscles physiology, Stroke Volume physiology, Heart Ventricles surgery, Muscles surgery
- Abstract
Skeletal muscle ventricles were constructed from the latissimus dorsi in seven dogs. All skeletal muscle ventricles underwent a vascular delay period followed by 4-7 weeks of electrical preconditioning. In group 1 (n = 5), the skeletal muscle ventricle was used to replace native right-heart function. Venous return from the superior and inferior venae cavae was directed to the skeletal muscle ventricle with outflow directed to the pulmonary artery. In group 2 (n = 2), the skeletal muscle ventricle was used for partial bypass of the right heart. In both groups, right-heart bypass was continued for as long as 8 hours. In group 1 after 4 hours of continuous complete right-heart bypass, stroke work was 163 +/- 63% of canine right ventricular stroke work. Skeletal muscle ventricle output was 1.14 +/- 0.02 l/min, central venous pressure was 13 +/- 1.5 mm Hg, and systemic systolic blood pressure was 95 +/- 9 mm Hg. Skeletal muscle ventricles are capable of performing the work of the right heart with near-physiological filling pressures.
- Published
- 1989
49. A comparison of Blalock-Taussig, Waterston, and polytetrafluoroethylene shunts in children less than two weeks of age.
- Author
-
Woolf PK, Stephenson LW, Meijboom E, Bavinck JH, Gardner TJ, Donahoo JS, Edie RN, and Edmunds LH Jr
- Subjects
- Age Factors, Aorta, Abdominal surgery, Aorta, Thoracic surgery, Heart Defects, Congenital mortality, Heart Failure etiology, Humans, Infant, Newborn, Methods, Palliative Care, Postoperative Complications, Pulmonary Artery surgery, Pulmonary Circulation, Subclavian Artery surgery, Time Factors, Blood Vessel Prosthesis, Heart Defects, Congenital surgery, Polytetrafluoroethylene
- Abstract
Results obtained with Blalock-Taussig, Waterston, and polytetrafluoroethylene (PTFE) shunts were compared in 67 cyanotic infants less than 2 weeks of age. A different shunt was preferably used at each of three institutions. The incidences of early shunt failure (3 out of 21, 14%), mortality after revision of early shunt failure (0 out of 3), and overall hospital mortality (1 out of 21, 5%) were all lowest for the PTFE shunt. Incidence of congestive heart failure secondary to excessive flow was comparable for the Blalock-Taussig and PTFE shunts, both of which were lower than the Waterston shunt. Cumulative probabilities of late shunt adequacy were calculated for hospital survivors. At 1 year, all shunts provided comparable adequate palliation (greater than 80%). Probability of late shunt failure was significantly higher (p = 0.04) for the PTFE shunt at 3.5 years. Results suggest that the PTFE shunt may be the safest and most effective shunt in neonates, but that elective shunt replacement or total repair may be warranted in the first or second year of life.
- Published
- 1984
- Full Text
- View/download PDF
50. Origin of the left coronary artery from the right pulmonary artery.
- Author
-
Bharati S, Chandra N, Stephenson LW, Wagner HR, Weinberg PM, and Lev M
- Subjects
- Aortic Coarctation pathology, Aortic Coarctation surgery, Coronary Vessel Anomalies pathology, Coronary Vessel Anomalies surgery, Humans, Infant, Male, Pulmonary Artery diagnostic imaging, Pulmonary Artery pathology, Radiography, Aortic Coarctation diagnosis, Coronary Vessel Anomalies diagnosis, Pulmonary Artery abnormalities
- Abstract
Origin of the left coronary artery from the right pulmonary artery has rarely been documented. This is the first such case in a heart with an intact ventricular septum and paraductal coarctation of the aorta. Although an antemortem diagnosis was made and the anomalous left coronary artery was ligated, the patient, a 3 1/2 month old infant, died 1 day after surgery. Autopsy confirmed the diagnosis, but revealed that the left coronary artery was dominant. It is believed that the fatal outcome in the infant was, in part, due to the dominance of the left coronary artery and the effects of the coarctation on the already ischemic left ventricle.
- Published
- 1984
- Full Text
- View/download PDF
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