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Laman A Gray - One of the best experts on this subject based on the ideXlab platform.

  • integrated data acquisition system for medical device testing and physiology research in compliance with good laboratory practices
    Biomedical Instrumentation & Technology, 2004
    Co-Authors: Steven C Koenig, Cary Woolard, Guy Drew, Lauren Unger, K J Gillars, Dan Ewert, Laman A Gray, George M Pantalos
    Abstract:

    In seeking approval from the US Food and Drug Administration (FDA) for clinical trial evaluation of an experimental medical device, a sponsor is required to submit experimental findings and support documentation to demonstrate device safety and efficacy that are in compliance with Good Laboratory Practices (GLP). The objective of this project was to develop an integrated data acquisition (DAQ) system and documentation strategy for monitoring and recording physiological data when testing medical devices in accordance with GLP guidelines mandated by the FDA. Data aquisition systems were developed as stand-alone instrumentation racks containing transducer amplifiers and signal processors, analog-to-digital converters for data storage, visual display and graphical user-interfaces, power conditioners, and test measurement devices. Engineering standard operating procedures (SOP) were developed to provide a written step-by-step process for calibrating, validating, and certifying each individual instrumentation unit and the integrated DAQ system. Engineering staff received GLP and SOP training and then completed the calibration, validation, and certification process for the individual instrumentation components and integrated DAQ system. Eight integrated DAQ systems have been successfully developed that were inspected by regulatory affairs consultants and determined to meet GLP guidelines. Two of these DAQ systems were used to support 40 of the pre-clinical animal studies evaluating the AbiCor artificial heart (ABIOMED, Danvers, MA). Based in part on these pre-clinical animal data, the AbioCor clinical trials began in July 2001. The process of developing integrated DAQ systems, SOP, and the validation and certification methods used to ensure GLP compliance are presented in this article.

  • creation of a diaphragm patch to facilitate placement of the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2004
    Co-Authors: Robert D Dowling, Aziz Ghaly, Laman A Gray
    Abstract:

    One of the concerns when placing a total artificial heart is whether the device will fit in the thoracic cavity without impinging on vital structures. We report the creation of a patch in a recipient of the AbioCor Implantable Replacement Heart that allowed for an appropriate fit of the device without adversely affecting pulmonary and hemodynamic functions.

  • initial experience with the AbioCor implantable replacement heart system
    The Journal of Thoracic and Cardiovascular Surgery, 2004
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    Abstract Objective We sought to evaluate the safety and efficacy of the first available totally implantable replacement heart (AbioCor Implantable Replacement Heart System) in the treatment of severe, irreversible biventricular heart failure in human patients. Methods Seven male adult patients with severe, irreversible biventricular failure (>70% thirty-day predicted mortality) who were not candidates for transplantation met all institutional review board study criteria and had placement of the AbioCor Implantable Replacement Heart. All were in cardiogenic shock despite maximal medical therapy, including inotropes and intra-aortic balloon pumps. Mean age was 66.7 ± 10.4 years (range, 51-79 years). Four of 7 patients had prior operations. Six had ischemic and one had idiopathic cardiomyopathy. All had 3-dimensional computer-simulated implantation of the thoracic unit that predicted adequate fit. At the time of the operation, the internal transcutaneous energy transfer coil, battery, and controller were placed. Biventriculectomy was then performed, and the thoracic unit was placed in an orthotopic position and attached to the atrial cuffs and outflow conduits with quick-connects. The flow was adjusted to 4 to 8 L/min. Central venous and left atrial pressures were maintained at 5 to 15 mm Hg. The device is powered through transcutaneous energy transfer. An atrial flow-balancing chamber is used to adjust left/right balance. The balance chamber and transcutaneous energy transfer eliminate the need for percutaneous lines. Results There was one intraoperative death caused by coagulopathic bleeding and one early death caused by an aprotinin reaction. There have been multiple morbidities primarily related to preexisting illness severity: 5 patients had prolonged intubation, 2 had hepatic failure (resolved in 1), 4 had renal failure (resolved in 3), and 1 each had recurrent gastrointestinal bleeding, acute cholecystitis requiring laparotomy, respiratory failure that resolved after 3 days of extracorporeal membrane oxygenation, and malignant hyperthermia (resolved). There were 3 late deaths: one caused by multiple systems organ failure (postoperative day 56), one caused by a cerebrovascular accident (postoperative day 142), and one caused by retroperitoneal bleeding and resultant multiple systems organ failure (postoperative day 151). This latter patient was not able to tolerate anticoagulation (no anticoagulation or antiplatelet therapy alone for 80% of the first 60 days) and had a transient ischemic attack on postoperative day 61 and a cerebrovascular accident on postoperative day 130. At autopsy, blood pumps were clean. The 2 patients who had large cerebrovascular accidents had thrombus on the atrial cage struts. These struts have been removed for future implants. There has been no significant hemolysis or device-related infections. The balance chamber has allowed for left/right balance in all patients (left atrial pressure within 5 mm Hg of right atrial pressure). Three patients have taken multiple (>50) trips out of the hospital, and 2 have been discharged from the hospital. Total days on support with the AbioCor are 759. Conclusion The initial clinical experience suggests that the AbioCor might be effective therapy in patients with advanced biventricular failure. There have been no significant device malfunctions. Two of these patients have been discharged from the hospital.

  • treadmill exercise in calves implanted with the AbioCor replacement heart
    Asaio Journal, 2003
    Co-Authors: Benjamin B Chiang, Laman A Gray, George M Pantalos, Steven W Etoch, Patricia B Cerrito, Karla Stevens, Karen Lott, Laura E Lott, Robert D Dowling
    Abstract:

    The aim of this study was to evaluate the function of the AbioCor artificial heart implanted in calves that underwent treadmill exercise testing and to investigate the cardiovascular and metabolic responses during exercise. Six calves were implanted with the AbioCor. One week after surgery, exercise training was undertaken and animals were put on a treadmill at a speed of 0.5-1.0 mph, with the AbioCor operating at the maximum heart rate of 150 beats per minute. During exercise, the left and right atrial pressures were significantly increased (p 0.05). The index of metabolic adequacy remained higher than 2.0, indicating that there was no substantial transition to anaerobic metabolism during exercise. There was an increased extraction of oxygen during exercise to meet the increased energy demands. Our study demonstrated that animals implanted with the AbioCor heart were able to maintain aerobic metabolism during low levels of exercise testing.

  • the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2003
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multi-system organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.

Robert D Dowling - One of the best experts on this subject based on the ideXlab platform.

  • creation of a diaphragm patch to facilitate placement of the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2004
    Co-Authors: Robert D Dowling, Aziz Ghaly, Laman A Gray
    Abstract:

    One of the concerns when placing a total artificial heart is whether the device will fit in the thoracic cavity without impinging on vital structures. We report the creation of a patch in a recipient of the AbioCor Implantable Replacement Heart that allowed for an appropriate fit of the device without adversely affecting pulmonary and hemodynamic functions.

  • initial experience with the AbioCor implantable replacement heart system
    The Journal of Thoracic and Cardiovascular Surgery, 2004
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    Abstract Objective We sought to evaluate the safety and efficacy of the first available totally implantable replacement heart (AbioCor Implantable Replacement Heart System) in the treatment of severe, irreversible biventricular heart failure in human patients. Methods Seven male adult patients with severe, irreversible biventricular failure (>70% thirty-day predicted mortality) who were not candidates for transplantation met all institutional review board study criteria and had placement of the AbioCor Implantable Replacement Heart. All were in cardiogenic shock despite maximal medical therapy, including inotropes and intra-aortic balloon pumps. Mean age was 66.7 ± 10.4 years (range, 51-79 years). Four of 7 patients had prior operations. Six had ischemic and one had idiopathic cardiomyopathy. All had 3-dimensional computer-simulated implantation of the thoracic unit that predicted adequate fit. At the time of the operation, the internal transcutaneous energy transfer coil, battery, and controller were placed. Biventriculectomy was then performed, and the thoracic unit was placed in an orthotopic position and attached to the atrial cuffs and outflow conduits with quick-connects. The flow was adjusted to 4 to 8 L/min. Central venous and left atrial pressures were maintained at 5 to 15 mm Hg. The device is powered through transcutaneous energy transfer. An atrial flow-balancing chamber is used to adjust left/right balance. The balance chamber and transcutaneous energy transfer eliminate the need for percutaneous lines. Results There was one intraoperative death caused by coagulopathic bleeding and one early death caused by an aprotinin reaction. There have been multiple morbidities primarily related to preexisting illness severity: 5 patients had prolonged intubation, 2 had hepatic failure (resolved in 1), 4 had renal failure (resolved in 3), and 1 each had recurrent gastrointestinal bleeding, acute cholecystitis requiring laparotomy, respiratory failure that resolved after 3 days of extracorporeal membrane oxygenation, and malignant hyperthermia (resolved). There were 3 late deaths: one caused by multiple systems organ failure (postoperative day 56), one caused by a cerebrovascular accident (postoperative day 142), and one caused by retroperitoneal bleeding and resultant multiple systems organ failure (postoperative day 151). This latter patient was not able to tolerate anticoagulation (no anticoagulation or antiplatelet therapy alone for 80% of the first 60 days) and had a transient ischemic attack on postoperative day 61 and a cerebrovascular accident on postoperative day 130. At autopsy, blood pumps were clean. The 2 patients who had large cerebrovascular accidents had thrombus on the atrial cage struts. These struts have been removed for future implants. There has been no significant hemolysis or device-related infections. The balance chamber has allowed for left/right balance in all patients (left atrial pressure within 5 mm Hg of right atrial pressure). Three patients have taken multiple (>50) trips out of the hospital, and 2 have been discharged from the hospital. Total days on support with the AbioCor are 759. Conclusion The initial clinical experience suggests that the AbioCor might be effective therapy in patients with advanced biventricular failure. There have been no significant device malfunctions. Two of these patients have been discharged from the hospital.

  • treadmill exercise in calves implanted with the AbioCor replacement heart
    Asaio Journal, 2003
    Co-Authors: Benjamin B Chiang, Laman A Gray, George M Pantalos, Steven W Etoch, Patricia B Cerrito, Karla Stevens, Karen Lott, Laura E Lott, Robert D Dowling
    Abstract:

    The aim of this study was to evaluate the function of the AbioCor artificial heart implanted in calves that underwent treadmill exercise testing and to investigate the cardiovascular and metabolic responses during exercise. Six calves were implanted with the AbioCor. One week after surgery, exercise training was undertaken and animals were put on a treadmill at a speed of 0.5-1.0 mph, with the AbioCor operating at the maximum heart rate of 150 beats per minute. During exercise, the left and right atrial pressures were significantly increased (p 0.05). The index of metabolic adequacy remained higher than 2.0, indicating that there was no substantial transition to anaerobic metabolism during exercise. There was an increased extraction of oxygen during exercise to meet the increased energy demands. Our study demonstrated that animals implanted with the AbioCor heart were able to maintain aerobic metabolism during low levels of exercise testing.

  • the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2003
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multi-system organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.

  • current status of the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2001
    Co-Authors: Laman A Gray, Robert D Dowling, Steven W Etoch, Karla A Stevens, Amy Johnson
    Abstract:

    Abstract Background . The AbioCor implantable replacement heart (IRH) has been developed as an alternative to transplant (ie, destination therapy). We report our experience with the AbioCor IRH in a bovine model at the University of Louisville. Methods . Male Holstein cows were used (85 to 115 kg). The internal controller, battery, and secondary transcutaneous energy transfer coil were implanted in the right flank. After cardiopulmonary bypass, the thoracic unit was implanted orthotopically. After removal of air and weaning from cardiopulmonary bypass, the AbioCor was connected to internal components and energy transfer through transcutaneous energy transfer coils was achieved. Results . Nineteen animals underwent implantation of the AbioCor IRH for a proposed 30-day duration. There were 6 deaths, none related to device malfunction. All animals demonstrated normal hemodynamics with normal pressures in the aorta, pulmonary artery, left atrium, and right atrium. There was no significant hemolysis and all animals demonstrated normal end organ function. The internal battery allowed for brief periods of untethered mobility. Conclusions . The AbioCor IRH has resulted in normal hemodynamics and normal end organ function without evidence of hemolysis in a bovine model.

O H Frazier - One of the best experts on this subject based on the ideXlab platform.

  • catheterization of the AbioCor implantable replacement heart evaluation of the unique physiology created by the device
    Texas Heart Institute Journal, 2006
    Co-Authors: Reynolds M Delgado, Toni Pool, Timothy J Myers, Nancy Scroggins, Mohamad A Nawar, Catalin Loghin, Igor D Gregoric, Branislav Radovancevic, O H Frazier
    Abstract:

    We performed the 1st catheterization of an AbioCor™ implantable replacement heart, in a patient who had developed high right-sided pump pressures, to determine whether the high pressures were caused by graft kinking or obstruction.

  • role of b type natriuretic peptide and effect of nesiritide after total cardiac replacement with the AbioCor total artificial heart
    Journal of Heart and Lung Transplantation, 2005
    Co-Authors: Reynolds M Delgado, Yasmin Wadia, Biswajit Kar, Whitson Ethridge, Aly Zewail, Toni Pool, Timothy J Myers, Nancy Scroggins, O H Frazier
    Abstract:

    Endogenous B-type natriuretic peptide (BNP) is thought to be produced in the cardiac ventricles. After sub-total cardiectomy and implantation of a total artificial heart (TAH), the abrupt withdrawal of BNP impairs renal function despite normal hemodynamic variables. We hypothesized that abrupt withdrawal of endogenous BNP may impair renal function and volume homeostasis and BNP may have a direct renal influence unrelated to its cardiovascular effect. Nesiritide infusion should be supplemented in the interim and weaned slowly until BNP levels normalize, which suggests that BNP is produced in tissues other than the cardiac ventricles.

  • initial experience with the AbioCor implantable replacement heart system
    The Journal of Thoracic and Cardiovascular Surgery, 2004
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    Abstract Objective We sought to evaluate the safety and efficacy of the first available totally implantable replacement heart (AbioCor Implantable Replacement Heart System) in the treatment of severe, irreversible biventricular heart failure in human patients. Methods Seven male adult patients with severe, irreversible biventricular failure (>70% thirty-day predicted mortality) who were not candidates for transplantation met all institutional review board study criteria and had placement of the AbioCor Implantable Replacement Heart. All were in cardiogenic shock despite maximal medical therapy, including inotropes and intra-aortic balloon pumps. Mean age was 66.7 ± 10.4 years (range, 51-79 years). Four of 7 patients had prior operations. Six had ischemic and one had idiopathic cardiomyopathy. All had 3-dimensional computer-simulated implantation of the thoracic unit that predicted adequate fit. At the time of the operation, the internal transcutaneous energy transfer coil, battery, and controller were placed. Biventriculectomy was then performed, and the thoracic unit was placed in an orthotopic position and attached to the atrial cuffs and outflow conduits with quick-connects. The flow was adjusted to 4 to 8 L/min. Central venous and left atrial pressures were maintained at 5 to 15 mm Hg. The device is powered through transcutaneous energy transfer. An atrial flow-balancing chamber is used to adjust left/right balance. The balance chamber and transcutaneous energy transfer eliminate the need for percutaneous lines. Results There was one intraoperative death caused by coagulopathic bleeding and one early death caused by an aprotinin reaction. There have been multiple morbidities primarily related to preexisting illness severity: 5 patients had prolonged intubation, 2 had hepatic failure (resolved in 1), 4 had renal failure (resolved in 3), and 1 each had recurrent gastrointestinal bleeding, acute cholecystitis requiring laparotomy, respiratory failure that resolved after 3 days of extracorporeal membrane oxygenation, and malignant hyperthermia (resolved). There were 3 late deaths: one caused by multiple systems organ failure (postoperative day 56), one caused by a cerebrovascular accident (postoperative day 142), and one caused by retroperitoneal bleeding and resultant multiple systems organ failure (postoperative day 151). This latter patient was not able to tolerate anticoagulation (no anticoagulation or antiplatelet therapy alone for 80% of the first 60 days) and had a transient ischemic attack on postoperative day 61 and a cerebrovascular accident on postoperative day 130. At autopsy, blood pumps were clean. The 2 patients who had large cerebrovascular accidents had thrombus on the atrial cage struts. These struts have been removed for future implants. There has been no significant hemolysis or device-related infections. The balance chamber has allowed for left/right balance in all patients (left atrial pressure within 5 mm Hg of right atrial pressure). Three patients have taken multiple (>50) trips out of the hospital, and 2 have been discharged from the hospital. Total days on support with the AbioCor are 759. Conclusion The initial clinical experience suggests that the AbioCor might be effective therapy in patients with advanced biventricular failure. There have been no significant device malfunctions. Two of these patients have been discharged from the hospital.

  • the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2003
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multi-system organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.

Louis E Samuels - One of the best experts on this subject based on the ideXlab platform.

  • use of the AbioCor replacement heart as destination therapy for end stage heart failure with irreversible pulmonary hypertension
    The Journal of Thoracic and Cardiovascular Surgery, 2004
    Co-Authors: Louis E Samuels, John W Entwistle, Elena C Holmes, Jane Fitzpatrick, Andrew S Wechsler
    Abstract:

    Fixed pulmonary hypertension is a contraindication for orthotopic heart transplantation. The AbioCor artificial heart (Abiomed Inc, Danvers, Mass) was designed as a totally internal replacement system for patients with endstage heart failure who are not eligible for heart transplantation. The purpose of this report is to describe the experience with the AbioCor artificial heart in the setting of a patient with severe biventricular failure and irreversible pulmonary hypertension.

  • initial experience with the AbioCor implantable replacement heart system
    The Journal of Thoracic and Cardiovascular Surgery, 2004
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    Abstract Objective We sought to evaluate the safety and efficacy of the first available totally implantable replacement heart (AbioCor Implantable Replacement Heart System) in the treatment of severe, irreversible biventricular heart failure in human patients. Methods Seven male adult patients with severe, irreversible biventricular failure (>70% thirty-day predicted mortality) who were not candidates for transplantation met all institutional review board study criteria and had placement of the AbioCor Implantable Replacement Heart. All were in cardiogenic shock despite maximal medical therapy, including inotropes and intra-aortic balloon pumps. Mean age was 66.7 ± 10.4 years (range, 51-79 years). Four of 7 patients had prior operations. Six had ischemic and one had idiopathic cardiomyopathy. All had 3-dimensional computer-simulated implantation of the thoracic unit that predicted adequate fit. At the time of the operation, the internal transcutaneous energy transfer coil, battery, and controller were placed. Biventriculectomy was then performed, and the thoracic unit was placed in an orthotopic position and attached to the atrial cuffs and outflow conduits with quick-connects. The flow was adjusted to 4 to 8 L/min. Central venous and left atrial pressures were maintained at 5 to 15 mm Hg. The device is powered through transcutaneous energy transfer. An atrial flow-balancing chamber is used to adjust left/right balance. The balance chamber and transcutaneous energy transfer eliminate the need for percutaneous lines. Results There was one intraoperative death caused by coagulopathic bleeding and one early death caused by an aprotinin reaction. There have been multiple morbidities primarily related to preexisting illness severity: 5 patients had prolonged intubation, 2 had hepatic failure (resolved in 1), 4 had renal failure (resolved in 3), and 1 each had recurrent gastrointestinal bleeding, acute cholecystitis requiring laparotomy, respiratory failure that resolved after 3 days of extracorporeal membrane oxygenation, and malignant hyperthermia (resolved). There were 3 late deaths: one caused by multiple systems organ failure (postoperative day 56), one caused by a cerebrovascular accident (postoperative day 142), and one caused by retroperitoneal bleeding and resultant multiple systems organ failure (postoperative day 151). This latter patient was not able to tolerate anticoagulation (no anticoagulation or antiplatelet therapy alone for 80% of the first 60 days) and had a transient ischemic attack on postoperative day 61 and a cerebrovascular accident on postoperative day 130. At autopsy, blood pumps were clean. The 2 patients who had large cerebrovascular accidents had thrombus on the atrial cage struts. These struts have been removed for future implants. There has been no significant hemolysis or device-related infections. The balance chamber has allowed for left/right balance in all patients (left atrial pressure within 5 mm Hg of right atrial pressure). Three patients have taken multiple (>50) trips out of the hospital, and 2 have been discharged from the hospital. Total days on support with the AbioCor are 759. Conclusion The initial clinical experience suggests that the AbioCor might be effective therapy in patients with advanced biventricular failure. There have been no significant device malfunctions. Two of these patients have been discharged from the hospital.

  • the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2003
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multi-system organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.

  • the AbioCor totally implantable replacement heart
    The American Heart Hospital Journal, 2003
    Co-Authors: Louis E Samuels
    Abstract:

    The AbioCor artificial heart (Abiomed, Inc., Danvers, MA) represents the latest technologic advancement in the quest for a total heart replacement system. The AbioCor is an electric heart with fully implantable components. The Food and Drug Administration approved a clinical trial in January 2001. The clinical trial was designed as an initial feasibility study to determine the safety and efficacy of this first generation system. The study criteria include end-stage adult heart failure patients who are not transplant candidates. These patients have biventricular failure with a predicted 30-day life expectancy of less than 30%. On July 2, 2001 the first AbioCor device was implanted. Six other patients have undergone implantation to date. Four of the seven have been successful as defined by the study parameters of 60-day survival with improved quality of life. Two patients were discharged from the hospital. Outpatient activities were possible in four patients. There have been no device malfunctions and no device-related infections. The trial is active and enrollment is ongoing.

Steven W Etoch - One of the best experts on this subject based on the ideXlab platform.

  • initial experience with the AbioCor implantable replacement heart system
    The Journal of Thoracic and Cardiovascular Surgery, 2004
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    Abstract Objective We sought to evaluate the safety and efficacy of the first available totally implantable replacement heart (AbioCor Implantable Replacement Heart System) in the treatment of severe, irreversible biventricular heart failure in human patients. Methods Seven male adult patients with severe, irreversible biventricular failure (>70% thirty-day predicted mortality) who were not candidates for transplantation met all institutional review board study criteria and had placement of the AbioCor Implantable Replacement Heart. All were in cardiogenic shock despite maximal medical therapy, including inotropes and intra-aortic balloon pumps. Mean age was 66.7 ± 10.4 years (range, 51-79 years). Four of 7 patients had prior operations. Six had ischemic and one had idiopathic cardiomyopathy. All had 3-dimensional computer-simulated implantation of the thoracic unit that predicted adequate fit. At the time of the operation, the internal transcutaneous energy transfer coil, battery, and controller were placed. Biventriculectomy was then performed, and the thoracic unit was placed in an orthotopic position and attached to the atrial cuffs and outflow conduits with quick-connects. The flow was adjusted to 4 to 8 L/min. Central venous and left atrial pressures were maintained at 5 to 15 mm Hg. The device is powered through transcutaneous energy transfer. An atrial flow-balancing chamber is used to adjust left/right balance. The balance chamber and transcutaneous energy transfer eliminate the need for percutaneous lines. Results There was one intraoperative death caused by coagulopathic bleeding and one early death caused by an aprotinin reaction. There have been multiple morbidities primarily related to preexisting illness severity: 5 patients had prolonged intubation, 2 had hepatic failure (resolved in 1), 4 had renal failure (resolved in 3), and 1 each had recurrent gastrointestinal bleeding, acute cholecystitis requiring laparotomy, respiratory failure that resolved after 3 days of extracorporeal membrane oxygenation, and malignant hyperthermia (resolved). There were 3 late deaths: one caused by multiple systems organ failure (postoperative day 56), one caused by a cerebrovascular accident (postoperative day 142), and one caused by retroperitoneal bleeding and resultant multiple systems organ failure (postoperative day 151). This latter patient was not able to tolerate anticoagulation (no anticoagulation or antiplatelet therapy alone for 80% of the first 60 days) and had a transient ischemic attack on postoperative day 61 and a cerebrovascular accident on postoperative day 130. At autopsy, blood pumps were clean. The 2 patients who had large cerebrovascular accidents had thrombus on the atrial cage struts. These struts have been removed for future implants. There has been no significant hemolysis or device-related infections. The balance chamber has allowed for left/right balance in all patients (left atrial pressure within 5 mm Hg of right atrial pressure). Three patients have taken multiple (>50) trips out of the hospital, and 2 have been discharged from the hospital. Total days on support with the AbioCor are 759. Conclusion The initial clinical experience suggests that the AbioCor might be effective therapy in patients with advanced biventricular failure. There have been no significant device malfunctions. Two of these patients have been discharged from the hospital.

  • treadmill exercise in calves implanted with the AbioCor replacement heart
    Asaio Journal, 2003
    Co-Authors: Benjamin B Chiang, Laman A Gray, George M Pantalos, Steven W Etoch, Patricia B Cerrito, Karla Stevens, Karen Lott, Laura E Lott, Robert D Dowling
    Abstract:

    The aim of this study was to evaluate the function of the AbioCor artificial heart implanted in calves that underwent treadmill exercise testing and to investigate the cardiovascular and metabolic responses during exercise. Six calves were implanted with the AbioCor. One week after surgery, exercise training was undertaken and animals were put on a treadmill at a speed of 0.5-1.0 mph, with the AbioCor operating at the maximum heart rate of 150 beats per minute. During exercise, the left and right atrial pressures were significantly increased (p 0.05). The index of metabolic adequacy remained higher than 2.0, indicating that there was no substantial transition to anaerobic metabolism during exercise. There was an increased extraction of oxygen during exercise to meet the increased energy demands. Our study demonstrated that animals implanted with the AbioCor heart were able to maintain aerobic metabolism during low levels of exercise testing.

  • the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2003
    Co-Authors: Robert D Dowling, Laman A Gray, Steven W Etoch, Louis E Samuels, John W Entwistle, Hillel Laks, Daniel Marelli, G S Couper, Gus J Vlahakes, O H Frazier
    Abstract:

    The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multi-system organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.

  • current status of the AbioCor implantable replacement heart
    The Annals of Thoracic Surgery, 2001
    Co-Authors: Laman A Gray, Robert D Dowling, Steven W Etoch, Karla A Stevens, Amy Johnson
    Abstract:

    Abstract Background . The AbioCor implantable replacement heart (IRH) has been developed as an alternative to transplant (ie, destination therapy). We report our experience with the AbioCor IRH in a bovine model at the University of Louisville. Methods . Male Holstein cows were used (85 to 115 kg). The internal controller, battery, and secondary transcutaneous energy transfer coil were implanted in the right flank. After cardiopulmonary bypass, the thoracic unit was implanted orthotopically. After removal of air and weaning from cardiopulmonary bypass, the AbioCor was connected to internal components and energy transfer through transcutaneous energy transfer coils was achieved. Results . Nineteen animals underwent implantation of the AbioCor IRH for a proposed 30-day duration. There were 6 deaths, none related to device malfunction. All animals demonstrated normal hemodynamics with normal pressures in the aorta, pulmonary artery, left atrium, and right atrium. There was no significant hemolysis and all animals demonstrated normal end organ function. The internal battery allowed for brief periods of untethered mobility. Conclusions . The AbioCor IRH has resulted in normal hemodynamics and normal end organ function without evidence of hemolysis in a bovine model.

  • initial experience with the AbioCor implantable replacement heart at the university of louisville
    Asaio Journal, 2000
    Co-Authors: Robert D Dowling, Steven W Etoch, Amy Johnson, Karla Stevens, A R T Butterfield, Steven E Koenig, Benjamin Chiang, L A Gray
    Abstract:

    Potential benefits of heart transplantation are limited by the severe donor organ shortage. The AbioCor implantable replacement heart has been developed as a potential alternative to heart transplantation. We report our initial experience with the AbioCor in a bovine model. A right thoracotomy was performed for access to the heart and great vessels. After initiation of cardiopulmonary bypass, excision of the native ventricles was followed by orthotopic placement of the IRH and complete implantation of the transcutaneous energy transfer coil, controller, and battery pack. Invasive monitoring of IVC, SVC, carotid artery, pulmonary artery, and left atrial (LA) pressures was performed in all animals. Twelve calves have undergone implantation of the AbioCor. There were three early deaths, one from bleeding, one from respiratory failure, and one from neurodysfunction from low flow during CPB. Nine animals have had a normal recovery and survived a mean of 24.5 days (range, 4-48 days). All the animals have demonstrated excellent hemodynamics with the maintenance of normal pressures in the LA, SVC, IVC, pulmonary artery, and aorta. Adjustment of the right-sided internal hydraulic fluid shunt has allowed for control of right-left balance and, thereby, manipulation of left and right side filling pressures. Late morbidity has consisted of neck wound infection and sepsis, pneumonia, and bleeding. Successful orthotopic implantation of all components of the AbioCor has been achieved in a bovine model. This device has demonstrated restoration of normal hemodynamics and excellent function of the atrial hydraulic shunt to achieve right-left balance.