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Right Ventricular Failure Post LVAD Implantation Corrected with Biventricular Support: An In-Vitro Model
S318
The Journal of Heart and Lung Transplantation, Vol 35, No 4S, April 2016
Methods: A Modified Frailty Index (MFI) has been utilised. It has a binary scale of five elements which allows easily reproducible assessment at the bedside: 1) Weak grip strength. 2) Physical exhaustion. 3) Slowness. 4) Low physical activity. 5) Unintentional weight loss. One point for a positive response in the each of the categories above is allocated, with 2 points being allocated dependent upon severity of responses for slowness and low physical activity. The scale of frailty is defined below: 0 - 1 points = non-frail 2 - 4 points = intermediate or pre-frail 5 - 7 points = positive for frailty phenotype. A Superior Frailty Index (SFI) was also calculated using the patients strongest grip strength. Results: We have characterised a total of 54 patients pre-transplant, and 27 post-transplant patients. In this cross sectional analysis the data identified the greatest prevalence of frailty amidst the pre-transplant patients with COPD and Pulmonary Fibrosis. The average MFI for the COPD category was 3.8 for the females and 3.1 for the men with the average age of this population of 56.5years. The fibrotic population, showed females scoring an average MFI of 3.5 and the men recording an average MFI of 3.8. This is juxtaposed with the lowest scoring category of patients being the CF population who averaged an MFI of 1.5 amongst the females and 2.0 for the males, their average age was 30.7years. Conclusion: The average MFI identified a population who were pre-frail not solely based upon their grip strength and their mental capacity. This has led to more people being referred for psychological support. We propose to continue collecting data and to explore if patients who have a positive frailty phenotype pre-transplant are ventilated for longer in ITU, are they more susceptible to episodes of infection and rejection. 5 patients who were captured pre-transplant have undergone transplantation and this data is currently being collected. 8( 75) Pregnancy Outcomes in 30 Lung Transplant Recipients S. Constantinescu ,1 L. Coscia,2 D. Armenti,2 M. Moritz.3 1Medicine, Temple University School of Medicine, Philadelphia, PA; 2National Transplantation Pregnancy Registry, Philadelphia, PA; 3Lehigh Valley Health Network, Allentown, PA. Purpose: The purpose of this study was to analyze pregnancy outcomes in female lung transplant recipients. Methods: Data were collected by the National Transplantation Pregnancy Registry (NTPR) via questionnaires, interviews, and medical records. Results: 30 female lung transplant recipients reported 40 pregnancies with 42 outcomes (one triplet pregnancy) conceived between June 1992-April 2015. 57% of the recipients were transplanted for cystic fibrosis. The mean age at transplant was 28±5.0 yrs and mean transplant-to-conception interval was 3.7±3.2 yrs. Outcomes included 23 live births, 13 miscarriages, 5 terminations and 1 ectopic pregnancy. Immunosuppression included cyclosporine (CsA) in 10 and tacrolimus in 30 pregnancies; 15% of the pregnancies had exposure to a mycophenolic acid product. Comorbid conditions during pregnancy included: hypertension 60%, diabetes 33%, infections 22%, and preeclampsia 7%. Five rejections were reported during pregnancy followed by 3 maternal deaths (9.9 mos, 1.6 yrs, and 4.3 yrs after pregnancy); four of these recipients were on CsA and were transplanted prior to 1996. With a maternal follow-up of 9.6±6.8 yrs, 18 recipients had adequate function (3 re-transplants), 4 had reduced or poor function, 1 had a non-functioning transplant (with reduced native lung function), and 7 had died. Among the 23 newborn, mean gestational age was 33.9±5.1 wks; 62% were preterm (< 37 wks). Mean birthweight was 2193±909 g; 62% were low birthweight (< 2500 g). Neonatal deaths were reported in association with the triplet pregnancy: one fetus spontaneously aborted at 14 weeks, followed by the death of the two remaining infants delivered at 22 wks; another infant was delivered at 26 wks and lived 4 days. One child had both hypospadias (repaired at 8 mos) and arteriovenous malformation (corrected when discovered at age 18). Another child had atrial and ventricular defects with pacemaker placement (mother
had same diagnosis). At last child follow-up, age 9.6±6.8 yrs, the 20 children were reported otherwise healthy and developing well. Conclusion: Successful pregnancy is possible after lung transplantation, though caution is advised as these are extremely high-risk pregnancies with high incidences of prematurity, low birthweight infants, and maternal mortality. Close surveillance of these recipients is warranted due to the negative impact of rejection during pregnancy on graft and recipient survival. 8( 76) Outcome of CentriMag Extracorporeal Mechanical Circulatory Support Use in Critical Cardiogenic Shock (INTERMACS 1) Patients V. Mehta ,1 J. Hasan,1 K. Oommen,1 S. Shaw,2 S.G. Williams,2 J. Barnard,1 N. Yonan,1 R.V. Venkateswaran.3 1Cardiothoracic Surgery, University Hospital of South Manchester, Manchester, United Kingdom; 2Cardiology, University Hospital of South Manchester, Manchester, United Kingdom; 3Director of Transplantation, Cardiothoracic Surgery, University Hospital of South Manchester, Manchester, United Kingdom. Purpose: The outcomes of patients presenting with INTERMACS-1 critical cardiogenic shock remain poor and they require multiple procedures to get through this illness. The aim of our study was to investigate the results of CentriMag short-term support as a bridge to decision in patients presenting with critical cardiogenic shock in our unit. Methods: We retrospectively analysed 46 consecutive patients from January 2005 to September 2015, who were treated with CentriMag device at our institution as bridge to decision. Patients requiring extracorporeal support for post cardiotomy shock and for primary graft dysfunction after heart transplantation were excluded. Results: Patients mean age was 40.1 years (range 15.7 - 62.0) and 33 (71%) were male. Primary diagnosis at presentation was ischaemic cardiomyopathy (n = 19; 41.3%), viral myocarditis (n= 8; 17.4%), Myocarditis-unspecified (n= 7; 15.2%), idiopathic dilated cardiomyopathy (n = 5; 10.9%), anthracycline induced myopathy (n= 2; 4.3%). Collectively, patients were supported for a total of 1696 days with mean duration of 37 (02 - 124) days. A total of 4(8.7%) patients were supported with peripheral VA ECMO, 5(10.9%) with central VA ECMO, 7(15.2%) with LVAD, 8(17.4%) with BiVAD, 22(47.8%) patients were initially treated with central VA ECMO and were then converted to short term BiVAD. The overall survival to successful explant from CentriMag was 65.2% (n= 30) and survival to hospital discharge was 56.5% (n= 26). Of these, 4(8.7%) had cardiac recovery and were successfully explanted, 16(34.8%) were bridged to heart transplantation. 10(21.7%) were bridged to long term left ventricular assist device, 2(4.3%) of these were later on transplanted and 1(2.2%) recovered to decommissioning. Overall 16 (34.8%) patients died while on CentriMag mechanical circulatory support. Complications included bleeding requiring reoperation/intervention in 17 (37%), renal failure requiring dialysis 23 (50%), infections 25(54.3%) including fungal infections in 9(19.6%), critical limb ischaemia 4 (8.7%) and stroke 7(15.2%). Conclusion: Our results demonstrate an excellent outcome with the use of CentriMag device in this seriously ill population. Despite requiring multiple procedures over 56% of patients were discharged from hospital. 8( 77) WITHDRAWN 8( 78) Right Ventricular Failure Post LVAD Implantation Corrected with Biventricular Support: An In-Vitro Model S. Shehab ,1 S.M. Allida,2 P.J. Newton,2 P.M. Davidson,3 P.S. MacDonalds,1 P.C. Jansz,1 C.S. Hayward.1 1Cardiology, St. Vincent’s Hospital, Sydney, Australia; 2Centre of Cardiovascular and Chronic Care, University of technology, Sydney, Sydney, Australia; 3School of Nursing, John Hopkins University, Sydney, MD. Purpose: Right ventricular failure post LVAD implantation is associated with high mortality. Management remains limited to pharmacological therapy and temporary mechanical support. Delayed RVAD support post LVAD implantation is associated with poor outcomes. However, with the advent of miniaturised, durable, continuous flow BiVAD and RVAD system, delayed
Abstracts S319 RVAD support with these devices may overcome existing limitations of current treatment alternative. To test this hypothesis, a mock circulatory loop was developed to simulate the human cardiovascular system in normal and heart failure states and to evaluate the haemodynamic impact of isolated left and biventricular assist devices in-vitro. Methods: Pulsatility in the circulation was maintained by pneumatic compression of silicon left and right ventricles. Venous, systemic and pulmonary compliances were replicated with air/water tanks, and systemic and pulmonary resistance were actively varied. A 40% glycerol solution was maintained at 37°C to simulate haematocrit of 34. Results: Normal circulation with low filling pressures and maintained cardiac output was simulated, as was established biventricular heart failure with elevated right and left filling pressures with low cardiac output. Biventricular failure supported with initial BiVAD support resulted in restored hemodynamic parameters, similar to those seen healthy conditions. However, biventricular failure supported with isolated LVAD resulted in persistent elevated right atrial pressures with reduced left atrial and pulmonary pressures. Delayed continuous flow RVAD support reduced right atrial pressures and increased systemic flow. Generated waveforms were very similar to physiological pulse patterns. Conclusion: In conclusion, normal and heart failure states, as well as right heart failure seen in association with isolated LVAD supported is able to be modelled, with return of normal physiological parameters with biventricular support.
8( 79) The Effect of Inflow Cannula Length on the Intraventricular Flow Field of the EvaHeart LVAD-Assisted Heart K. May-Newman ,1 J. Moon,1 V. Ramesh,1 B. Herold,1 R. Montes,1 J. Campos,1 P. Isingoma,1 R. Benkowski.2 1Bioengineering, San Diego State University, San Diego, CA; 2B-Squared Medical Device Solutions, LLC, Fort Worth, TX. Purpose: Positioning of the LVAD inflow cannula has been shown to be important for left ventricular (LV) flow. Previous studies have identified cannula malposition as a significant risk for pump thrombosis. Thrombus development is a consequence of altered flow dynamics, which can produce areas of flow stasis or high shear that promote coagulation. The goal of this study was to visualize the LV flow field surrounding the apical inflow cannula of the EvaHeart centrifugal LVAD for a range of cannula lengths and support conditions. Methods: Experimental studies were performed using a mock loop with a customized silicone LV and the EvaHeart LVAD to simulate the biomechanics of the LVAD-assisted heart. The 2-D velocity field in the midplane of the LV was measured with particle image velocimetry at 40Hz. The baseline condition was adjusted to produce an aortic flow rate of 3.5 L/min at 70 bpm. Two different Evaheart LVAD speeds were tested, one which produced aortic valve opening (1800 rpm) and one in which the aortic valve was closed (2300 rpm). A transparent inflow cannula was tested at three different positions, corresponding to 1cm (C_1), 2cm (C_2, standard length) and 3cm (C_3) into the LV. Results: The velocity field shows stasis in the apical region surrounding the inflow cannula. A normal vortex ring forms in all cases, but the size, path and strength are affected by the cannula position. During diastole, the large clockwise anterior vortex grows, but its circulation is reduced as the cannula is inserted further into the LV. The counter-clockwise vortex exhibits a flow split at C_3 but not C_2 resulting in a peak in circulation at C_2. The flow split occurs during diastole, increasing flow to the apical regions adjacent to the cannula. This flow pattern of the C_3 position also results in increased pulsatility adjacent to the cannula, compared with position C_2. The C_1
position had the greatest pulsatility and the least flow stasis of all three positions, especially in the apical region. The results of this study indicate that the C_3 position, in which the cannula is inserted the furthest into the LV, produces a flow pattern with a lower apical thrombus risk than the C_2 pattern. Conclusion: Overall, the C_1 cannula position exhibits the least apical flow stasis and greatest pulsatility and is predicted to have the lowest thromboembolic risk of the three cannula positions studied. 8( 80) WITHDRAWN 8( 81) Modulation of Autonomic Tone Assessed by Heart Rate Variability in Advanced Heart Failure Patients Treated with an Extra-Aortic Counterpulsation (EACP) System: A Single Center Experience A. Kao ,1 D. Georgakopoulos,2 J. Smith,1 D. Pomfret,3 S. Aggarwal.4 1Medicine, Saint Luke’s Cardiovascular, Kansas City, MO; 2Sunshine Heart, Eden Prairie, MN; 3Sunshine Heart, Kansas City, MN; 4Cardiovascular and Thoracic Surgery, Saint Luke’s Mid-America Heart and Lung, Kansas City, MO. Purpose: Advanced heart failure (HF) is a characterized by poor functional capacity, fluid retention, elevated filling pressures and increased arrhythmia burden. Autonomic imbalance leading to sympathetic activation and reduced vagal activity plays a key role in mediating these symptoms. Heart rate variability (HRV) is a physiologic marker that provides an assessment of autonomic function. The EACP device is a chronic counterpulsation therapy consisting of an external cuff wrapped around the ascending aorta. We report the chronic effects of EACP therapy on autonomic function in advanced HF patients using HRV derived from implantable CRT/ICD devices. Methods: We retrospectively obtained HRV reports from patients in the US Feasibility study which evaluated preliminary safety and efficacy of EACP from 2010-2012. Patients (N= 4) were identified, 3M, NYHA Class III, 42.3±4.3 years, CRT (N= 2), ICD (N= 4). All patients received maximally tolerated, guideline directed medical therapy. HRV was measured using CRM device algorithm. Briefly, 5 minute median intervals were derived from atrial sensed cycle lengths. HRV was defined as the standard deviation of these intervals (SDAAM) for each 24 hour period. Results: SDAAM was measured without EACP 130±17.3 days and 185±36.9 days with EACP (p= NS). SDAAM demonstrated significant improvement with chronic EACP therapy increasing from 55±4.6ms to 85±5.4 (p< 0.01). No significant change in heart rate was observed between no EACP 78.5±3.8 min-1 and chronic EACP 79.3±6 min-1. All data mean±se. Conclusion: In this small cohort, treatment with EACP was associated with clinically relevant improvement in autonomic balance assessed by chronic HRV measurements derived from an independent, validated algorithm. Studies have shown SDAMM ≤ 50ms predicts significant mortality risk. Thus, EACP may be expected to significantly impact the risk of cardiovascular death and hospitalization. Further studies are warranted to assess the mechanisms whereby counterpulsation may influence sympathetic/parasympathetic balance, which may include increased baroreceptor signaling arising from enhanced pulsatility. 8( 82) Off-Pump HeartWare HVAD Left Ventricular Assist Device Implantation R. Moayedifar ,1 J. Riebandt,1 T. Haberl,1 K. Dimitrov,1 D. Wiedemann,1 T. Schlöglhofer,2 H. Schima,2 G. Laufer,1 D. Zimpfer.1 1Department of Cardiac Surgery, Medical University Vienna, Vienna, Austria; 2Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria. Purpose: Left ventricular assist devices (LVAD) are routinely implanted with cardiopulmonary bypass support. Patients with terminal heart failure are typically multimorbid and might therefore profit from a less invasive implant technique with avoidance of cardiopulmonary bypass. We report our experience with off-pump Heartware HVAD LVAD implantation. Methods: We retrospectively reviewed data of 19 patients who underwent off-pump Heartware HVAD implantation from November 2012 to June 2015.
The Journal of Heart and Lung Transplantation, Vol 35, No 4S, April 2016
Methods: A Modified Frailty Index (MFI) has been utilised. It has a binary scale of five elements which allows easily reproducible assessment at the bedside: 1) Weak grip strength. 2) Physical exhaustion. 3) Slowness. 4) Low physical activity. 5) Unintentional weight loss. One point for a positive response in the each of the categories above is allocated, with 2 points being allocated dependent upon severity of responses for slowness and low physical activity. The scale of frailty is defined below: 0 - 1 points = non-frail 2 - 4 points = intermediate or pre-frail 5 - 7 points = positive for frailty phenotype. A Superior Frailty Index (SFI) was also calculated using the patients strongest grip strength. Results: We have characterised a total of 54 patients pre-transplant, and 27 post-transplant patients. In this cross sectional analysis the data identified the greatest prevalence of frailty amidst the pre-transplant patients with COPD and Pulmonary Fibrosis. The average MFI for the COPD category was 3.8 for the females and 3.1 for the men with the average age of this population of 56.5years. The fibrotic population, showed females scoring an average MFI of 3.5 and the men recording an average MFI of 3.8. This is juxtaposed with the lowest scoring category of patients being the CF population who averaged an MFI of 1.5 amongst the females and 2.0 for the males, their average age was 30.7years. Conclusion: The average MFI identified a population who were pre-frail not solely based upon their grip strength and their mental capacity. This has led to more people being referred for psychological support. We propose to continue collecting data and to explore if patients who have a positive frailty phenotype pre-transplant are ventilated for longer in ITU, are they more susceptible to episodes of infection and rejection. 5 patients who were captured pre-transplant have undergone transplantation and this data is currently being collected. 8( 75) Pregnancy Outcomes in 30 Lung Transplant Recipients S. Constantinescu ,1 L. Coscia,2 D. Armenti,2 M. Moritz.3 1Medicine, Temple University School of Medicine, Philadelphia, PA; 2National Transplantation Pregnancy Registry, Philadelphia, PA; 3Lehigh Valley Health Network, Allentown, PA. Purpose: The purpose of this study was to analyze pregnancy outcomes in female lung transplant recipients. Methods: Data were collected by the National Transplantation Pregnancy Registry (NTPR) via questionnaires, interviews, and medical records. Results: 30 female lung transplant recipients reported 40 pregnancies with 42 outcomes (one triplet pregnancy) conceived between June 1992-April 2015. 57% of the recipients were transplanted for cystic fibrosis. The mean age at transplant was 28±5.0 yrs and mean transplant-to-conception interval was 3.7±3.2 yrs. Outcomes included 23 live births, 13 miscarriages, 5 terminations and 1 ectopic pregnancy. Immunosuppression included cyclosporine (CsA) in 10 and tacrolimus in 30 pregnancies; 15% of the pregnancies had exposure to a mycophenolic acid product. Comorbid conditions during pregnancy included: hypertension 60%, diabetes 33%, infections 22%, and preeclampsia 7%. Five rejections were reported during pregnancy followed by 3 maternal deaths (9.9 mos, 1.6 yrs, and 4.3 yrs after pregnancy); four of these recipients were on CsA and were transplanted prior to 1996. With a maternal follow-up of 9.6±6.8 yrs, 18 recipients had adequate function (3 re-transplants), 4 had reduced or poor function, 1 had a non-functioning transplant (with reduced native lung function), and 7 had died. Among the 23 newborn, mean gestational age was 33.9±5.1 wks; 62% were preterm (< 37 wks). Mean birthweight was 2193±909 g; 62% were low birthweight (< 2500 g). Neonatal deaths were reported in association with the triplet pregnancy: one fetus spontaneously aborted at 14 weeks, followed by the death of the two remaining infants delivered at 22 wks; another infant was delivered at 26 wks and lived 4 days. One child had both hypospadias (repaired at 8 mos) and arteriovenous malformation (corrected when discovered at age 18). Another child had atrial and ventricular defects with pacemaker placement (mother
had same diagnosis). At last child follow-up, age 9.6±6.8 yrs, the 20 children were reported otherwise healthy and developing well. Conclusion: Successful pregnancy is possible after lung transplantation, though caution is advised as these are extremely high-risk pregnancies with high incidences of prematurity, low birthweight infants, and maternal mortality. Close surveillance of these recipients is warranted due to the negative impact of rejection during pregnancy on graft and recipient survival. 8( 76) Outcome of CentriMag Extracorporeal Mechanical Circulatory Support Use in Critical Cardiogenic Shock (INTERMACS 1) Patients V. Mehta ,1 J. Hasan,1 K. Oommen,1 S. Shaw,2 S.G. Williams,2 J. Barnard,1 N. Yonan,1 R.V. Venkateswaran.3 1Cardiothoracic Surgery, University Hospital of South Manchester, Manchester, United Kingdom; 2Cardiology, University Hospital of South Manchester, Manchester, United Kingdom; 3Director of Transplantation, Cardiothoracic Surgery, University Hospital of South Manchester, Manchester, United Kingdom. Purpose: The outcomes of patients presenting with INTERMACS-1 critical cardiogenic shock remain poor and they require multiple procedures to get through this illness. The aim of our study was to investigate the results of CentriMag short-term support as a bridge to decision in patients presenting with critical cardiogenic shock in our unit. Methods: We retrospectively analysed 46 consecutive patients from January 2005 to September 2015, who were treated with CentriMag device at our institution as bridge to decision. Patients requiring extracorporeal support for post cardiotomy shock and for primary graft dysfunction after heart transplantation were excluded. Results: Patients mean age was 40.1 years (range 15.7 - 62.0) and 33 (71%) were male. Primary diagnosis at presentation was ischaemic cardiomyopathy (n = 19; 41.3%), viral myocarditis (n= 8; 17.4%), Myocarditis-unspecified (n= 7; 15.2%), idiopathic dilated cardiomyopathy (n = 5; 10.9%), anthracycline induced myopathy (n= 2; 4.3%). Collectively, patients were supported for a total of 1696 days with mean duration of 37 (02 - 124) days. A total of 4(8.7%) patients were supported with peripheral VA ECMO, 5(10.9%) with central VA ECMO, 7(15.2%) with LVAD, 8(17.4%) with BiVAD, 22(47.8%) patients were initially treated with central VA ECMO and were then converted to short term BiVAD. The overall survival to successful explant from CentriMag was 65.2% (n= 30) and survival to hospital discharge was 56.5% (n= 26). Of these, 4(8.7%) had cardiac recovery and were successfully explanted, 16(34.8%) were bridged to heart transplantation. 10(21.7%) were bridged to long term left ventricular assist device, 2(4.3%) of these were later on transplanted and 1(2.2%) recovered to decommissioning. Overall 16 (34.8%) patients died while on CentriMag mechanical circulatory support. Complications included bleeding requiring reoperation/intervention in 17 (37%), renal failure requiring dialysis 23 (50%), infections 25(54.3%) including fungal infections in 9(19.6%), critical limb ischaemia 4 (8.7%) and stroke 7(15.2%). Conclusion: Our results demonstrate an excellent outcome with the use of CentriMag device in this seriously ill population. Despite requiring multiple procedures over 56% of patients were discharged from hospital. 8( 77) WITHDRAWN 8( 78) Right Ventricular Failure Post LVAD Implantation Corrected with Biventricular Support: An In-Vitro Model S. Shehab ,1 S.M. Allida,2 P.J. Newton,2 P.M. Davidson,3 P.S. MacDonalds,1 P.C. Jansz,1 C.S. Hayward.1 1Cardiology, St. Vincent’s Hospital, Sydney, Australia; 2Centre of Cardiovascular and Chronic Care, University of technology, Sydney, Sydney, Australia; 3School of Nursing, John Hopkins University, Sydney, MD. Purpose: Right ventricular failure post LVAD implantation is associated with high mortality. Management remains limited to pharmacological therapy and temporary mechanical support. Delayed RVAD support post LVAD implantation is associated with poor outcomes. However, with the advent of miniaturised, durable, continuous flow BiVAD and RVAD system, delayed
Abstracts S319 RVAD support with these devices may overcome existing limitations of current treatment alternative. To test this hypothesis, a mock circulatory loop was developed to simulate the human cardiovascular system in normal and heart failure states and to evaluate the haemodynamic impact of isolated left and biventricular assist devices in-vitro. Methods: Pulsatility in the circulation was maintained by pneumatic compression of silicon left and right ventricles. Venous, systemic and pulmonary compliances were replicated with air/water tanks, and systemic and pulmonary resistance were actively varied. A 40% glycerol solution was maintained at 37°C to simulate haematocrit of 34. Results: Normal circulation with low filling pressures and maintained cardiac output was simulated, as was established biventricular heart failure with elevated right and left filling pressures with low cardiac output. Biventricular failure supported with initial BiVAD support resulted in restored hemodynamic parameters, similar to those seen healthy conditions. However, biventricular failure supported with isolated LVAD resulted in persistent elevated right atrial pressures with reduced left atrial and pulmonary pressures. Delayed continuous flow RVAD support reduced right atrial pressures and increased systemic flow. Generated waveforms were very similar to physiological pulse patterns. Conclusion: In conclusion, normal and heart failure states, as well as right heart failure seen in association with isolated LVAD supported is able to be modelled, with return of normal physiological parameters with biventricular support.
8( 79) The Effect of Inflow Cannula Length on the Intraventricular Flow Field of the EvaHeart LVAD-Assisted Heart K. May-Newman ,1 J. Moon,1 V. Ramesh,1 B. Herold,1 R. Montes,1 J. Campos,1 P. Isingoma,1 R. Benkowski.2 1Bioengineering, San Diego State University, San Diego, CA; 2B-Squared Medical Device Solutions, LLC, Fort Worth, TX. Purpose: Positioning of the LVAD inflow cannula has been shown to be important for left ventricular (LV) flow. Previous studies have identified cannula malposition as a significant risk for pump thrombosis. Thrombus development is a consequence of altered flow dynamics, which can produce areas of flow stasis or high shear that promote coagulation. The goal of this study was to visualize the LV flow field surrounding the apical inflow cannula of the EvaHeart centrifugal LVAD for a range of cannula lengths and support conditions. Methods: Experimental studies were performed using a mock loop with a customized silicone LV and the EvaHeart LVAD to simulate the biomechanics of the LVAD-assisted heart. The 2-D velocity field in the midplane of the LV was measured with particle image velocimetry at 40Hz. The baseline condition was adjusted to produce an aortic flow rate of 3.5 L/min at 70 bpm. Two different Evaheart LVAD speeds were tested, one which produced aortic valve opening (1800 rpm) and one in which the aortic valve was closed (2300 rpm). A transparent inflow cannula was tested at three different positions, corresponding to 1cm (C_1), 2cm (C_2, standard length) and 3cm (C_3) into the LV. Results: The velocity field shows stasis in the apical region surrounding the inflow cannula. A normal vortex ring forms in all cases, but the size, path and strength are affected by the cannula position. During diastole, the large clockwise anterior vortex grows, but its circulation is reduced as the cannula is inserted further into the LV. The counter-clockwise vortex exhibits a flow split at C_3 but not C_2 resulting in a peak in circulation at C_2. The flow split occurs during diastole, increasing flow to the apical regions adjacent to the cannula. This flow pattern of the C_3 position also results in increased pulsatility adjacent to the cannula, compared with position C_2. The C_1
position had the greatest pulsatility and the least flow stasis of all three positions, especially in the apical region. The results of this study indicate that the C_3 position, in which the cannula is inserted the furthest into the LV, produces a flow pattern with a lower apical thrombus risk than the C_2 pattern. Conclusion: Overall, the C_1 cannula position exhibits the least apical flow stasis and greatest pulsatility and is predicted to have the lowest thromboembolic risk of the three cannula positions studied. 8( 80) WITHDRAWN 8( 81) Modulation of Autonomic Tone Assessed by Heart Rate Variability in Advanced Heart Failure Patients Treated with an Extra-Aortic Counterpulsation (EACP) System: A Single Center Experience A. Kao ,1 D. Georgakopoulos,2 J. Smith,1 D. Pomfret,3 S. Aggarwal.4 1Medicine, Saint Luke’s Cardiovascular, Kansas City, MO; 2Sunshine Heart, Eden Prairie, MN; 3Sunshine Heart, Kansas City, MN; 4Cardiovascular and Thoracic Surgery, Saint Luke’s Mid-America Heart and Lung, Kansas City, MO. Purpose: Advanced heart failure (HF) is a characterized by poor functional capacity, fluid retention, elevated filling pressures and increased arrhythmia burden. Autonomic imbalance leading to sympathetic activation and reduced vagal activity plays a key role in mediating these symptoms. Heart rate variability (HRV) is a physiologic marker that provides an assessment of autonomic function. The EACP device is a chronic counterpulsation therapy consisting of an external cuff wrapped around the ascending aorta. We report the chronic effects of EACP therapy on autonomic function in advanced HF patients using HRV derived from implantable CRT/ICD devices. Methods: We retrospectively obtained HRV reports from patients in the US Feasibility study which evaluated preliminary safety and efficacy of EACP from 2010-2012. Patients (N= 4) were identified, 3M, NYHA Class III, 42.3±4.3 years, CRT (N= 2), ICD (N= 4). All patients received maximally tolerated, guideline directed medical therapy. HRV was measured using CRM device algorithm. Briefly, 5 minute median intervals were derived from atrial sensed cycle lengths. HRV was defined as the standard deviation of these intervals (SDAAM) for each 24 hour period. Results: SDAAM was measured without EACP 130±17.3 days and 185±36.9 days with EACP (p= NS). SDAAM demonstrated significant improvement with chronic EACP therapy increasing from 55±4.6ms to 85±5.4 (p< 0.01). No significant change in heart rate was observed between no EACP 78.5±3.8 min-1 and chronic EACP 79.3±6 min-1. All data mean±se. Conclusion: In this small cohort, treatment with EACP was associated with clinically relevant improvement in autonomic balance assessed by chronic HRV measurements derived from an independent, validated algorithm. Studies have shown SDAMM ≤ 50ms predicts significant mortality risk. Thus, EACP may be expected to significantly impact the risk of cardiovascular death and hospitalization. Further studies are warranted to assess the mechanisms whereby counterpulsation may influence sympathetic/parasympathetic balance, which may include increased baroreceptor signaling arising from enhanced pulsatility. 8( 82) Off-Pump HeartWare HVAD Left Ventricular Assist Device Implantation R. Moayedifar ,1 J. Riebandt,1 T. Haberl,1 K. Dimitrov,1 D. Wiedemann,1 T. Schlöglhofer,2 H. Schima,2 G. Laufer,1 D. Zimpfer.1 1Department of Cardiac Surgery, Medical University Vienna, Vienna, Austria; 2Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria. Purpose: Left ventricular assist devices (LVAD) are routinely implanted with cardiopulmonary bypass support. Patients with terminal heart failure are typically multimorbid and might therefore profit from a less invasive implant technique with avoidance of cardiopulmonary bypass. We report our experience with off-pump Heartware HVAD LVAD implantation. Methods: We retrospectively reviewed data of 19 patients who underwent off-pump Heartware HVAD implantation from November 2012 to June 2015.