- Email: [email protected]
Sub-Acute Animal Implantation of a Novel Bioprosthethic Artificial Heart
S174
The Journal of Heart and Lung Transplantation, Vol 32, No 4S, April 2013
(1, 3, 5y) was: F(86, 78, 70%) & M(88, 81, 74%)(Figure). Unadjusted HR for all-cause mortality was 0.85(0.68-1.07,p¼0.18). After adjustment: HR 0.86 (0.67-1.11,po0.67).
Conclusions: While prior studies have shown increased mortality in women with VADs, we demonstrate that women bridged to HT have similar survival to men post-HT. While there was a trend towards increased LVAD utilization in women, this was not statistically significant. These findings are surprising in light of the availability of the Heartmate II, which permit use in patients with lower BMI. 462 Non-Responders to Antiplatelet Therapy in Patients with Left Ventricular Assist Devices J. Riebandt,1 S. Mahr,1 T. Haberl,1 S. Panzer,2 H. Schima,1,3 G. Laufer,1 D. Zimpfer.1 1Department of Cardiac Surgery Medical University of Vienna, Vienna, Austria; 2Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria; 3Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria. Purpose: Thromboembolic complications are a deleterious adverse event after left ventricular assist device (LVAD) implantation. Because of individual responsiveness to antiplatelet treatment with the COXinhibitor aspirin and P2Y12-inhibitors as clopidogrel and prasugrel, personalized treatment based on platelet function testing may significantly reduce thromboembolic complications in LVAD patients. The present study was designed to define the frequency of aspirin and clopidogrel resistence in LVAD patients. Methods and Materials: Responsiveness to antiplatelet treatment was prospectively assessed by multiple electrode aggregometry in 39 (mean age 52⫾11yrs., ischemic cardiomyopathy 56.4%) LVAD outpatients (HVADs n¼30, HeartMate IIs n¼9). Twenty-five patients received the standard daily dose of 100mg aspirin, four were treated with 200mg aspirin, one patient with 75mg clopidogrel and three with a combination of 100mg aspirin and either 75mg clopidogrel (n¼2) or 10mg prasugrel. The daily aspirin dosage was doubled in nonresponders and patients were tested again after two weeks. Results: Multiple electrode aggregometry revealed non-responsiveness to the initial antiplatelet regimen in three patients (7.7%) and only moderate responsiveness in one patient (2.6%). The remaining 35 patients (89.7%) showed a good in vitro efficacy of the antiplatelet therapy. An adaption of the antiplatelet therapy by doubling the daily aspirin dosage led to adequate platelet inhibition, as revealed by multiple electrode aggregrometry, two weeks after change of treatment. Conclusions: As shown by objective measures, non-responsiveness to antiplatelet therapy is a common finding in patients after left ventricular assist device implantation. Therefore, personalized treatment according to the platelet function testing may reduce the incidence of thromboembolic complications.
463 Development of a Novel Tissue-Compatible Apical Inflow Cannula for an Implantable VAD T. Mizuno, T. Tsukiya, Y. Takawa, E. Tatsumi. Dept. of Artificial Organs. National Cerebral and Cardiovascular Center Institute, Suita, Osaka, Japan. Purpose: Clinical application of VAD is a potent therapeutic option for treating the patients with heart failure. However, as the VAD support period prolonged, the incidence of device-related complication, such as wedge thrombus, has been increasing. We already reported on new axial flow blood pump featuring a hydrodynamically levitated impeller with superior mechanical durability and anti-thrombogenesity. However, a measure against device-related complication occurred in the other components was not considered sufficiently. In this study, we developed a novel tissue-compatible polyester velour covered inflow cannula for preventing the wedge thrombus, and evaluated its performance in a series of animal tests. Methods and Materials: Eight calves (BW: 62-99 kg) underwent VAD implantation with our new axial flow blood pump. In the first two animals, a titanium-made inflow cannula with a smooth surface was used. In the following six animals, the outside of the cylindrical inflow cannula tip was wrapped with tissue-compatible polyester velour material. Outer diameters of the cannula tip was 20 mm, respectively, and the length of the cannula tip was 30 mm. The portion of the velour protruding from the apex was made to be 20 mm in length. Results: All animals were sacrificed on 90-92 POD on schedule. At autopsies, first two animals with smooth surface titanium inflow cannula demonstrated wedge thrombus formation at the cannula insertion site of the ventricular apex. The granulomatous tissue covered and partially occluded the tip of the inflow cannula. In contrast, six cases with newly developed cannula revealed no wedge thrombus formation around the outside of the inflow cannulas, and the polyester velour was completely enveloped with the neointimal tissue presumably grown from the ventricular endocardium. Conclusions: In conclusion, our newly developed tissue-compatible inflow cannula with polyester velour material successfully reduced the wedge thrombus formation in a series of 3 months animal implantation. 464 Sub-Acute Animal Implantation of a Novel Bioprosthethic Artificial Heart C. Latremouille,1 D. Duveau,2 B. Fellah,3 B. Cholley,4 P. Desseigne,2 D. Meleard,4 O. Gauthier,3 J.-C. Perles,5 A. Capel,5 P. Jansen,5 A. Carpentier.1 1Cardiovascular Surgery European Hospital George Pompidou, Paris, France; 2Thorax Institute, Laennec Hospital, Nantes, France; 3National Veterinary School, Nantes, France; 4Anesthesia and Intensive Care, European Hospital George Pompidou, Paris, France; 5 Carmat SA, Velizy, France. Purpose: The Carmat total artificial heart (TAH) is a recently developed electro-hydraulically driven biventricular system. It is designed as an alternative to heart transplant and placed in orthotopic position. The TAH has bioprosthetic blood-contacting surfaces and provides 3-9 l/min pulsatile flow in response to preload changes detected by the device. The purpose of this pre-clinical study was to monitor device performance and physiologic response during 48 hours functioning in an animal model. Methods and Materials: Five female calves of the Charolais race, 2-4 months old, weighing 100-110kg, were selected. The TAH was implanted via mid-sternotomy and powered by an external console through a percutaneous driveline. Animals were maintained under anesthesia during the study. The procedure was managed by a team of veterinarians, cardiac surgeons and clinical anesthesiologists/intensivists. Hemodynamic measurements, diuresis and blood samples to assess venous oxygen saturation and serum lactate were taken before implantation and during device functioning. Results: Baseline cardiac output of the native heart was 13.0⫾2.2 l/min. The TAH maintained a pulsatile flow between 7 and 9 l/min in all
Abstracts animals. The mean arterial pressure was 119⫾8 mmHg at baseline, 75⫾4 mmHg at 24 and 82⫾10 mmHg at 48 hours, with pulse pressure (systolic-diastolic) 42⫾9 mmHg at baseline 36⫾11 mmHg at 24 hours and 41⫾12 mmHg at 48 hours. Serum lactate decreased from 9.8⫾4.5 mmol/l post-CPB to 1.6⫾0.2 mmol/l at 24 hours and 1.2⫾0.6 mmol/l at 48 hours. Venous oxygen saturation at baseline was 73⫾18%, and remained stable at 78⫾7.5% at 24 hours and 83⫾0% at 48 hours. Diuresis averaged 321⫾172 ml/hour. It was decided to stop the procedures at 3.5 and 16 hours for technical reasons and at 36, 49 and 51 hours per protocol. Conclusions: The implantation technique for the Carmat TAH is similar to heart transplantation. In a Charolais calf model under anesthetized conditions, the TAH is capable to produce pulsatile flow up to 9 l/min and restore tissue perfusion. 465 Novoseven Use To Reduce Peri-Operative Bleeding Following HeartMate II Implant T.A. Snyder, S.P. Howell, K.E. Nelson, N.M. Chelikani, A.E. Ghuloom, P.J. Kannaly, J.S. Chaffin, C.C. Elkins, D.A. Horstmanshof, J.W. Long. Integris Advanced Cardiac Care Integris Baptist Medical Center, Oklahoma City, OK. Purpose: Peri-operative bleeding is a significant complication of left ventricular assist device (LVAD) implantation. Excessive bleeding requiring substantial blood product adminstration can contribute to sustained systemic inflammatory response syndrome (SIRS), tissue edema, pulmonary dysfunction, prolonged ventilator requirement, and even right heart heart failure. We describe the use use of recombinant human activated caogulation factor VII (Novoseven, Novo-Norsk) to reduce peri-operative bleeding. Methods and Materials: In this single center, retrospective, nonrandomized review, we analysed our use of Novoseven in the operating room (OR) or intensive care unit (ICU) to manage bleeding following implantation of the HeartMate II. 133 patients were implanted from Jan 1, 2012 through Nov 1, 2012, with 65 of those receiving Novoseven. Total chest tube drainage (CTD), ICU stay, hospital length of stay (LOS), thromboembolic (TE) events, and bleeding events were compared between the 2 groups using Stastica (Statsoft). Results: 65 patients received an average of 5.8 mg of Novoseven. 27 received Novoseven in the OR, 10 in the ICU, and 28 in both locations. There was no significant difference in surviavl at 1, 3, or 6 months. CTD was higher in patients who did not receive Novoseven by an average of 120 mL, but there was no significant differnce in ICU stay (4.7 vs. 5.2 days, p¼N.S.) or average LOS (22.4 vs. 21.3, p¼N.S.). There was also no statistical differnce in TE rate, but patients receiving Novoseven were 1.8 times more likely to experience a GIB (p o 0.05). There were no peri-operative CVAs in Novoseven recipients and 1 in a patient not receiving it. Conclusions: Novoseven was used in 65 of 133 HeartMate II recipients with no apparent adverse effects. An increased risk of GIB observed in patients receiving Novoseven may reflect a population at higher risk for bleeding. Further study to identify those at highest risk for bleeding could improve the use of Novoseven to ameliorate peri-operative bleeding associated with LVAD implantation. 466 Influence of Partial Mechanical Left Ventricular Support on Metabolism of Neuroendocrine Hormones and Exercise Capacity H.A. Welp, A. Rukosujew, J.R. Sindermann, A. Hoffmeier, M. Scherer, S. Martens. Department of Cardiac Surgery University Hospital Munster, Munster, NRW, Germany. ¨ ¨ Purpose: Myocardial recovery has been observed after placement of left ventricular assist devices (LVAD) in some patients awaiting cardiac transplantation. LVADs provide profound volume and pressure unloading while restoring systemic blood flow. However,
S175 the optimal degree of left ventricular unloading during LVAD support is unknown. Methods and Materials: Twenty patients with an LVAD underwent cardiopulmonary exercise testing employing spiroergometry. Once weekly, the level of support (measured as LVAD output) was reduced by 25 % and exercise testing repeated the day afterwards. Left ventricular unloading was assessed by echocardiographic measurement of LVEDD. Blood samples for plasma epinephrine, plasma norepinephrine and plasma renin activity were taken before and immediately after the exercise test. Plasma lactate was assessed every two minutes during the test. Results: Reduction of ventricular support to 75%, 50% and 25% lead to a significant increase in LVEDD compared to baseline. Increasing support from 50% to 75% leads to a rise in peak oxygen consumption and maximum exercise capacity. Exercise leads to a significant increase of norepinephrine and epinephrine levels at each level of support. Plasma norepinephrine and epinephrine levels were not significantly different at the four levels of support before and after exercise testing. Plasma renin activity at rest was significantly higher at 25%, 50% and 100% of support than it was at 75%. After exercise testing, plasma renin activity was significantly higher than at rest in all groups. However, the difference was significantly lower when support was at 75% as compared to 25%, 50% and 100%. The time interval for lactate to reach normal levels was significantly shorter at 75%. Conclusions: These results suggest that partial loading of the left ventricle does not result in a linear neuroendocrine response and exercise capacity. There seems to be a physiologic optimum during which the left ventricular assist device support is most beneficial. 467 Structured Rehabilitation Program in LVAD Patients Leads to Shortened Lengths of Stay R.R. Bunge,1 C. Perme,2 T. Motomura,1 M. Loebe,1 B.A. Bruckner.1 1 Cardiovascular Surgery The Methodist Hospital DeBakey Heart & Vascular Center, Houston, TX; 2Physical Therapy, The Methodist Hospital, Houston, TX. Purpose: Candidates for LVAD implantation tend to have poor functional status due to their heart failure. A structured rehabilitation program is essential for these patients to regain functional mobility post-LVAD implant. Methods and Materials: Our physical therapy program is personalized and has 4 phases which address functional limitations. Phase-I: patients who are in the acute phase with multiple medical problems and/or unable to stand. Phase-II: patients in the subacute phase; continue to have multiple medical problems but who are stable and ready to start pre-gait activities. Phase-III: patients with resolving medical problems who are able to start gait re-education activities. Phase-IV: stable and without significant medical problems. The physical therapy evaluation includes the assessment of mental status, vital signs, skin integrity, strength, range of motion, sensation, coordination, balance, gait, endurance, and the prior level of function. The program is initiated within 48 hours of implant. The physical therapy occurs once daily for 7 days/week and the duration of a treatment session is 15 minutes to 1 hour. Results: 91 patients went through our rehabilitation program starting Jan 1, 2010 – Dec 31, 2011. Demographics: Male 75% vs Female 25%; patients were mostly INTERMACS 1-2 pre-VAD. Average postimplant ICU days ¼ 10.4; Post-implant total Length of Stay (LOS) days (average) ¼ 20.1. Compared to 2008-2009 which was preimplementation of our structured PT program, post-implant LOS was 37.5 days on average. During our current study period, discharge to home was 41% and discharge to temporary acute care facility was 59%. Conclusions: LVAD patients are able to recover more effectively from their severe heart failure status with the aid of an appropriate mobility program. Our aggressive stepwise PT program provides clinical benefit for post-LVAD recovery as demonstrated by our low LOS following LVAD implantation.
The Journal of Heart and Lung Transplantation, Vol 32, No 4S, April 2013
(1, 3, 5y) was: F(86, 78, 70%) & M(88, 81, 74%)(Figure). Unadjusted HR for all-cause mortality was 0.85(0.68-1.07,p¼0.18). After adjustment: HR 0.86 (0.67-1.11,po0.67).
Conclusions: While prior studies have shown increased mortality in women with VADs, we demonstrate that women bridged to HT have similar survival to men post-HT. While there was a trend towards increased LVAD utilization in women, this was not statistically significant. These findings are surprising in light of the availability of the Heartmate II, which permit use in patients with lower BMI. 462 Non-Responders to Antiplatelet Therapy in Patients with Left Ventricular Assist Devices J. Riebandt,1 S. Mahr,1 T. Haberl,1 S. Panzer,2 H. Schima,1,3 G. Laufer,1 D. Zimpfer.1 1Department of Cardiac Surgery Medical University of Vienna, Vienna, Austria; 2Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria; 3Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria. Purpose: Thromboembolic complications are a deleterious adverse event after left ventricular assist device (LVAD) implantation. Because of individual responsiveness to antiplatelet treatment with the COXinhibitor aspirin and P2Y12-inhibitors as clopidogrel and prasugrel, personalized treatment based on platelet function testing may significantly reduce thromboembolic complications in LVAD patients. The present study was designed to define the frequency of aspirin and clopidogrel resistence in LVAD patients. Methods and Materials: Responsiveness to antiplatelet treatment was prospectively assessed by multiple electrode aggregometry in 39 (mean age 52⫾11yrs., ischemic cardiomyopathy 56.4%) LVAD outpatients (HVADs n¼30, HeartMate IIs n¼9). Twenty-five patients received the standard daily dose of 100mg aspirin, four were treated with 200mg aspirin, one patient with 75mg clopidogrel and three with a combination of 100mg aspirin and either 75mg clopidogrel (n¼2) or 10mg prasugrel. The daily aspirin dosage was doubled in nonresponders and patients were tested again after two weeks. Results: Multiple electrode aggregometry revealed non-responsiveness to the initial antiplatelet regimen in three patients (7.7%) and only moderate responsiveness in one patient (2.6%). The remaining 35 patients (89.7%) showed a good in vitro efficacy of the antiplatelet therapy. An adaption of the antiplatelet therapy by doubling the daily aspirin dosage led to adequate platelet inhibition, as revealed by multiple electrode aggregrometry, two weeks after change of treatment. Conclusions: As shown by objective measures, non-responsiveness to antiplatelet therapy is a common finding in patients after left ventricular assist device implantation. Therefore, personalized treatment according to the platelet function testing may reduce the incidence of thromboembolic complications.
463 Development of a Novel Tissue-Compatible Apical Inflow Cannula for an Implantable VAD T. Mizuno, T. Tsukiya, Y. Takawa, E. Tatsumi. Dept. of Artificial Organs. National Cerebral and Cardiovascular Center Institute, Suita, Osaka, Japan. Purpose: Clinical application of VAD is a potent therapeutic option for treating the patients with heart failure. However, as the VAD support period prolonged, the incidence of device-related complication, such as wedge thrombus, has been increasing. We already reported on new axial flow blood pump featuring a hydrodynamically levitated impeller with superior mechanical durability and anti-thrombogenesity. However, a measure against device-related complication occurred in the other components was not considered sufficiently. In this study, we developed a novel tissue-compatible polyester velour covered inflow cannula for preventing the wedge thrombus, and evaluated its performance in a series of animal tests. Methods and Materials: Eight calves (BW: 62-99 kg) underwent VAD implantation with our new axial flow blood pump. In the first two animals, a titanium-made inflow cannula with a smooth surface was used. In the following six animals, the outside of the cylindrical inflow cannula tip was wrapped with tissue-compatible polyester velour material. Outer diameters of the cannula tip was 20 mm, respectively, and the length of the cannula tip was 30 mm. The portion of the velour protruding from the apex was made to be 20 mm in length. Results: All animals were sacrificed on 90-92 POD on schedule. At autopsies, first two animals with smooth surface titanium inflow cannula demonstrated wedge thrombus formation at the cannula insertion site of the ventricular apex. The granulomatous tissue covered and partially occluded the tip of the inflow cannula. In contrast, six cases with newly developed cannula revealed no wedge thrombus formation around the outside of the inflow cannulas, and the polyester velour was completely enveloped with the neointimal tissue presumably grown from the ventricular endocardium. Conclusions: In conclusion, our newly developed tissue-compatible inflow cannula with polyester velour material successfully reduced the wedge thrombus formation in a series of 3 months animal implantation. 464 Sub-Acute Animal Implantation of a Novel Bioprosthethic Artificial Heart C. Latremouille,1 D. Duveau,2 B. Fellah,3 B. Cholley,4 P. Desseigne,2 D. Meleard,4 O. Gauthier,3 J.-C. Perles,5 A. Capel,5 P. Jansen,5 A. Carpentier.1 1Cardiovascular Surgery European Hospital George Pompidou, Paris, France; 2Thorax Institute, Laennec Hospital, Nantes, France; 3National Veterinary School, Nantes, France; 4Anesthesia and Intensive Care, European Hospital George Pompidou, Paris, France; 5 Carmat SA, Velizy, France. Purpose: The Carmat total artificial heart (TAH) is a recently developed electro-hydraulically driven biventricular system. It is designed as an alternative to heart transplant and placed in orthotopic position. The TAH has bioprosthetic blood-contacting surfaces and provides 3-9 l/min pulsatile flow in response to preload changes detected by the device. The purpose of this pre-clinical study was to monitor device performance and physiologic response during 48 hours functioning in an animal model. Methods and Materials: Five female calves of the Charolais race, 2-4 months old, weighing 100-110kg, were selected. The TAH was implanted via mid-sternotomy and powered by an external console through a percutaneous driveline. Animals were maintained under anesthesia during the study. The procedure was managed by a team of veterinarians, cardiac surgeons and clinical anesthesiologists/intensivists. Hemodynamic measurements, diuresis and blood samples to assess venous oxygen saturation and serum lactate were taken before implantation and during device functioning. Results: Baseline cardiac output of the native heart was 13.0⫾2.2 l/min. The TAH maintained a pulsatile flow between 7 and 9 l/min in all
Abstracts animals. The mean arterial pressure was 119⫾8 mmHg at baseline, 75⫾4 mmHg at 24 and 82⫾10 mmHg at 48 hours, with pulse pressure (systolic-diastolic) 42⫾9 mmHg at baseline 36⫾11 mmHg at 24 hours and 41⫾12 mmHg at 48 hours. Serum lactate decreased from 9.8⫾4.5 mmol/l post-CPB to 1.6⫾0.2 mmol/l at 24 hours and 1.2⫾0.6 mmol/l at 48 hours. Venous oxygen saturation at baseline was 73⫾18%, and remained stable at 78⫾7.5% at 24 hours and 83⫾0% at 48 hours. Diuresis averaged 321⫾172 ml/hour. It was decided to stop the procedures at 3.5 and 16 hours for technical reasons and at 36, 49 and 51 hours per protocol. Conclusions: The implantation technique for the Carmat TAH is similar to heart transplantation. In a Charolais calf model under anesthetized conditions, the TAH is capable to produce pulsatile flow up to 9 l/min and restore tissue perfusion. 465 Novoseven Use To Reduce Peri-Operative Bleeding Following HeartMate II Implant T.A. Snyder, S.P. Howell, K.E. Nelson, N.M. Chelikani, A.E. Ghuloom, P.J. Kannaly, J.S. Chaffin, C.C. Elkins, D.A. Horstmanshof, J.W. Long. Integris Advanced Cardiac Care Integris Baptist Medical Center, Oklahoma City, OK. Purpose: Peri-operative bleeding is a significant complication of left ventricular assist device (LVAD) implantation. Excessive bleeding requiring substantial blood product adminstration can contribute to sustained systemic inflammatory response syndrome (SIRS), tissue edema, pulmonary dysfunction, prolonged ventilator requirement, and even right heart heart failure. We describe the use use of recombinant human activated caogulation factor VII (Novoseven, Novo-Norsk) to reduce peri-operative bleeding. Methods and Materials: In this single center, retrospective, nonrandomized review, we analysed our use of Novoseven in the operating room (OR) or intensive care unit (ICU) to manage bleeding following implantation of the HeartMate II. 133 patients were implanted from Jan 1, 2012 through Nov 1, 2012, with 65 of those receiving Novoseven. Total chest tube drainage (CTD), ICU stay, hospital length of stay (LOS), thromboembolic (TE) events, and bleeding events were compared between the 2 groups using Stastica (Statsoft). Results: 65 patients received an average of 5.8 mg of Novoseven. 27 received Novoseven in the OR, 10 in the ICU, and 28 in both locations. There was no significant difference in surviavl at 1, 3, or 6 months. CTD was higher in patients who did not receive Novoseven by an average of 120 mL, but there was no significant differnce in ICU stay (4.7 vs. 5.2 days, p¼N.S.) or average LOS (22.4 vs. 21.3, p¼N.S.). There was also no statistical differnce in TE rate, but patients receiving Novoseven were 1.8 times more likely to experience a GIB (p o 0.05). There were no peri-operative CVAs in Novoseven recipients and 1 in a patient not receiving it. Conclusions: Novoseven was used in 65 of 133 HeartMate II recipients with no apparent adverse effects. An increased risk of GIB observed in patients receiving Novoseven may reflect a population at higher risk for bleeding. Further study to identify those at highest risk for bleeding could improve the use of Novoseven to ameliorate peri-operative bleeding associated with LVAD implantation. 466 Influence of Partial Mechanical Left Ventricular Support on Metabolism of Neuroendocrine Hormones and Exercise Capacity H.A. Welp, A. Rukosujew, J.R. Sindermann, A. Hoffmeier, M. Scherer, S. Martens. Department of Cardiac Surgery University Hospital Munster, Munster, NRW, Germany. ¨ ¨ Purpose: Myocardial recovery has been observed after placement of left ventricular assist devices (LVAD) in some patients awaiting cardiac transplantation. LVADs provide profound volume and pressure unloading while restoring systemic blood flow. However,
S175 the optimal degree of left ventricular unloading during LVAD support is unknown. Methods and Materials: Twenty patients with an LVAD underwent cardiopulmonary exercise testing employing spiroergometry. Once weekly, the level of support (measured as LVAD output) was reduced by 25 % and exercise testing repeated the day afterwards. Left ventricular unloading was assessed by echocardiographic measurement of LVEDD. Blood samples for plasma epinephrine, plasma norepinephrine and plasma renin activity were taken before and immediately after the exercise test. Plasma lactate was assessed every two minutes during the test. Results: Reduction of ventricular support to 75%, 50% and 25% lead to a significant increase in LVEDD compared to baseline. Increasing support from 50% to 75% leads to a rise in peak oxygen consumption and maximum exercise capacity. Exercise leads to a significant increase of norepinephrine and epinephrine levels at each level of support. Plasma norepinephrine and epinephrine levels were not significantly different at the four levels of support before and after exercise testing. Plasma renin activity at rest was significantly higher at 25%, 50% and 100% of support than it was at 75%. After exercise testing, plasma renin activity was significantly higher than at rest in all groups. However, the difference was significantly lower when support was at 75% as compared to 25%, 50% and 100%. The time interval for lactate to reach normal levels was significantly shorter at 75%. Conclusions: These results suggest that partial loading of the left ventricle does not result in a linear neuroendocrine response and exercise capacity. There seems to be a physiologic optimum during which the left ventricular assist device support is most beneficial. 467 Structured Rehabilitation Program in LVAD Patients Leads to Shortened Lengths of Stay R.R. Bunge,1 C. Perme,2 T. Motomura,1 M. Loebe,1 B.A. Bruckner.1 1 Cardiovascular Surgery The Methodist Hospital DeBakey Heart & Vascular Center, Houston, TX; 2Physical Therapy, The Methodist Hospital, Houston, TX. Purpose: Candidates for LVAD implantation tend to have poor functional status due to their heart failure. A structured rehabilitation program is essential for these patients to regain functional mobility post-LVAD implant. Methods and Materials: Our physical therapy program is personalized and has 4 phases which address functional limitations. Phase-I: patients who are in the acute phase with multiple medical problems and/or unable to stand. Phase-II: patients in the subacute phase; continue to have multiple medical problems but who are stable and ready to start pre-gait activities. Phase-III: patients with resolving medical problems who are able to start gait re-education activities. Phase-IV: stable and without significant medical problems. The physical therapy evaluation includes the assessment of mental status, vital signs, skin integrity, strength, range of motion, sensation, coordination, balance, gait, endurance, and the prior level of function. The program is initiated within 48 hours of implant. The physical therapy occurs once daily for 7 days/week and the duration of a treatment session is 15 minutes to 1 hour. Results: 91 patients went through our rehabilitation program starting Jan 1, 2010 – Dec 31, 2011. Demographics: Male 75% vs Female 25%; patients were mostly INTERMACS 1-2 pre-VAD. Average postimplant ICU days ¼ 10.4; Post-implant total Length of Stay (LOS) days (average) ¼ 20.1. Compared to 2008-2009 which was preimplementation of our structured PT program, post-implant LOS was 37.5 days on average. During our current study period, discharge to home was 41% and discharge to temporary acute care facility was 59%. Conclusions: LVAD patients are able to recover more effectively from their severe heart failure status with the aid of an appropriate mobility program. Our aggressive stepwise PT program provides clinical benefit for post-LVAD recovery as demonstrated by our low LOS following LVAD implantation.