- Email: [email protected]
715: Initial In Vivo Testing of a Self-Balancing Pulsatile Continuous Flow Total Artificial Heart
S314
Abstracts
increases, increasing LAP and reducing RAP. When speed pulsatility was added, the left pump performance decreases slightly, while the right pump performance increases, allowing the degree of speed pulsatility to become an additional active control to balance pump performance. Conclusions: The CFTAH demonstrated its capability of balancing atrial pressures via passive differential atrial pressure feedback without the need for any sensors. Initial in vivo studies are underway to further evaluate its performance.
The Journal of Heart and Lung Transplantation February 2009
cantly improve cardiac output (CO). A motorless, volume displacement pump based on artificial muscle technology could reproduce the AK. This study assesses mechanical effects of this pump on the right cavities in an animal model of AF. Methods and Materials: Atripump is a dome shape silicone coated biometal actuator 5 ⫻ 45mm. The biometal is electrically actuated by a pacemaker like control unit. In 10 sheep the right atrium (RA) was surgically exposed and the dome sutured onto it. AF was induced with rapid epicardial pacing (600 beats/min). Swan-Ganz catheter was inserted in the left jugular vein to measure the central venous pressure and pulmonary pressure. RA ejection fraction (EF) was assessed with intracardiac ultrasound in baseline, AF and assisted AF status. A flow meter on pulmonary artery measured ventricle output. Results: The dome’s contraction rate was 60/min with power supply of 10V, 300mA for 100ms and run for 2 hours. Mean temperature on the RA was 39⫾1.5 °C. RA EF was 30% in baseline, 5% in AF and 22% in assisted AF conditions. Mean central venous pressure was 8⫾2mmHg in baseline, 15⫾6mmHg in AF and 12⫾5 mmHg in assisted AF conditions. Mean pulmonary artery pressure was 16⫾5mmHg, 15⫾6mmHg and 17⫾5mmHg respectively (p⫽0.5). CO was 5.3⫾0.3 l/min in baseline, 4.4⫾0.6 l/min in AF and 5.1⫾0.3 l/min in assisted AF status (p⬍0.01). Conclusions: Placed on the right side, the artificial muscle restores the AK and improves CO. In patients with end stage cardiac failure and permanent AF, if implanted on both sides, it would improve CO and possibly delay or even avoid complex surgical treatment such as VAD implantation or heart transplant. 715 Initial In Vivo Testing of a Self-Balancing Pulsatile Continuous Flow Total Artificial Heart L.A.R. Golding, K. Fukamachi, D.J. Horvath, A.L. Massiello, H. Fumoto, Y. Arakawa, J. Catanese, J.-F. Chen, N. Mielke, T. Horai Lerner Research Institute, Cleveland Clinic, Cleveland, OH
714 Biometal Artificial Muscle Restores Atrial Kick in a Permanent Atrial Fibrillation Animal Model and Could Represent a New Tool in the Treatment of End Stage Heart Failure P. Tozzi1, D. Hayoz2, F. Salchli3, L.K. von Segesser1 1CHUV, Lausanne, Switzerland; 2Hopital Cantonal de Fribourg, Fribourg, Switzerland; 3CETT, Yverdon-les-Bains, Switzerland Purpose: Half of the patients with end stage heart failure suffer from persistent atrial fibrillation (AF). Current AF treatment can control ventricular rhythm but often fails to restore the transport function of the atrium. Atrial kick (AK) accounts for 10 to 15% of the ventricle ejection fraction. Any device able to restore the AK should signifi-
Purpose: Acute Implants of a unique, new concept Continouos Flow Total Artificial Heart (CFTAH) were done to confirm passive self balancing of right/left pump flows. Methods and Materials: After the CFTAH was implanted in 2 calves, pump performance and hemodynamic parameters were recorded over the full range of pump operational speeds (2,000 to 3,000 rpm). A similar data set over the same speed range was acquired under a series of induced hemodynamic states created by varying circulating blood volume (CBV), systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR). Results: Atrial pressures remained within physiologic ranges (1 to 9 mm Hg) with increasing pump flows. The automatic speed control algorithm (a sensorless controller) calculated pump flow based on motor speed and power values and showed good correlation with measured and calculated values. In acute study CFTAH -1 the only conditions where the atrial balance criteria (LAP-RAP ⫽ ⫹10 to -10 mm Hg) were not met occurred at one instance of very high PVR (804 dyne䡠sec䡠cm-5), where LAP – RAP was -11 mm Hg and also at 2800 and 3000 rpm for the condition of high CBV (3 liters of saline infused), where LAP – RAP was ⫹11 and ⫹13 mm Hg respectively. The extent of SVR and PVR relationships tested is shown with the normal range of values for SVR and PVR shown by the enclosed box. Conclusions: These acute studies demonstrated: 1. Accurate estimation of pump flow and SVR values calculated by the physiologic controller from only motor speed and current feedback 2. Passive self regulation of flows and pressures was demonstrated by atrial pressure balancing in response to altered physiologic states of varying CBV, SVR, and PVR over the full range of pump operating speeds.
The Journal of Heart and Lung Transplantation Volume 28, Number 2S
Abstracts
S315
transplants. Further, the long-term impact of the resulting increased ischemic time on survival and the added cost of procurement that resulted from TAC should be quantified to assess the full effect of TAC outcomes. Heart transplantation before and after 2006 UNOS allocation change. Transplants before allocation change (2 years) n ⴝ 80 1. Candidate Status 1A 1B 2 2. Waiting time (mean, days) 3. Ischemic time (mean, min) 4. Imported donor heart 5. Thirty-day mortality
19 16 45 89
(24%) (20%) (56%)
198
Transplants after allocation change (2 years) n ⴝ 70
30(43%) 23(33%) 17(24%) 71 222
P value
0.01 0.06 0.0001 0.46 0.04
43
(54%)
46(66%)
0.18
76
(95%)
68(97%)
0.70
P ⬍ 0.05 for statistical significance
717 Predictors of Time on the Lung Transplant Waiting List after Implementation of the Lung Allocation Score (LAS) D. Hadjiliadis1, J. Munson1, V.N. Ahya1, J. Lee1, R.M. Kotloff1, A. Pochettino2, J.D. Christie1 1University of Pennsylvania, Philadelphia, PA; 2University of Pennsylvania, Philadelphia, PA
716 The Impact of 2006 United Network for Organ Sharing Thoracic Organ Allocation Policy Change: Mission Accomplished? J.N. Nativi1, A.G. Kfoury1, C. Myrick2, M. Peters2, D. Renlund1, P. Fisher1, E. Gilbert1, F. Bader1, A. Singhal1, D. Bull1, M. Everitt1, J. Stehlik1 1UTAH Cardiac Transplant Program, Salt Lake City, UT; 2Intermountain Donor Services, Salt Lake City, UT Purpose: United Network for Organ Sharing (UNOS) thoracic organ allocation change (TAC) in 2006 intended to reduce deaths on waiting list by expanding regional organ sharing. As such, organs would be allocated to the sickest recipients with higher listing status. Our aim was to determine the impact of TAC on a program with a historically higher proportion of status 2 heart transplants. Methods and Materials: We compared procurement activity (OPO data) and heart transplant activity within the UTAH Cardiac Transplant Program for two years before and two years after the TAC. Results: TAC resulted in a dramatic decrease in status 2 transplants accompanied by increase in status 1A transplants, with a nonsignificant decrease in the waiting time. A higher number of donor organs were imported after TAC, which resulted in a significant increase in ischemic time (table). There was no significant difference in the mortality on the waiting list (6% vs 5%, p ⫽ 0.76) and the short-term post-transplant survival was similar. Conclusions: The expanded regional sharing from TAC resulted in less status 2 patients being transplanted in favor of an increase of status 1A
Purpose: A prior single center study has suggested that LAS, recipient height and type of transplant received are all significant predictors of time on the waiting list for patients awaiting lung transplantation, since LAS implementation. However, national studies to assess these findings are lacking. A study utilizing United Network of Organ Sharing (UNOS) data was undertaken to answer these questions. Methods and Materials: Waiting list data from UNOS were obtained for patients transplanted from 5/4/05 to 2/1/08. Demographic data, including recipient height were obtained. In addition, UNOS region of transplant, blood group and LAS at the time of transplant were collected. Multivariable linear regression analysis was utilized to identify predictors of time on the waiting list. Results: There were 4041 transplant recipients during the study period. Their baseline characteristics are seen in the table. On multivariable analysis LAS score and height had a significantly inverse relationship with time on the waiting list, while receipt of a double lung transplant resulted in a significant increase of time on the waiting list: LAS p⬍0.001; height p⫽0.035; bilateral transplant p⫽0.002. When blood groups were added to the model, the results remained significant and blood group O was associated with longer times on the waiting list (p⫽0.008). Finally, when region of UNOS was included in the model, height lost its significance, while type of transplant and LAS remained significant predictors of waiting list time. Seven regions had significantly different waiting times, five longer and two shorter than average. Conclusions: LAS score and type of transplant influence time spent on the waiting list. Height might play a role in certain UNOS regions. Baseline characteristics LAS Height (m) Age Gender (male) Type of transplant (bilateral) Blood group A O AB B
41.9⫾13.6(iqrange:33.6-44.4) 1.68⫾0.15 (iq range: 1.63-1.77) 52.5⫾13.0 (iq range: 46-62) 2300 (56.9%) 2491 (62.9%) 1633 (40.4%) 1806 (44.7%) 176 (4.4%) 424 (10.5%)
Abstracts
increases, increasing LAP and reducing RAP. When speed pulsatility was added, the left pump performance decreases slightly, while the right pump performance increases, allowing the degree of speed pulsatility to become an additional active control to balance pump performance. Conclusions: The CFTAH demonstrated its capability of balancing atrial pressures via passive differential atrial pressure feedback without the need for any sensors. Initial in vivo studies are underway to further evaluate its performance.
The Journal of Heart and Lung Transplantation February 2009
cantly improve cardiac output (CO). A motorless, volume displacement pump based on artificial muscle technology could reproduce the AK. This study assesses mechanical effects of this pump on the right cavities in an animal model of AF. Methods and Materials: Atripump is a dome shape silicone coated biometal actuator 5 ⫻ 45mm. The biometal is electrically actuated by a pacemaker like control unit. In 10 sheep the right atrium (RA) was surgically exposed and the dome sutured onto it. AF was induced with rapid epicardial pacing (600 beats/min). Swan-Ganz catheter was inserted in the left jugular vein to measure the central venous pressure and pulmonary pressure. RA ejection fraction (EF) was assessed with intracardiac ultrasound in baseline, AF and assisted AF status. A flow meter on pulmonary artery measured ventricle output. Results: The dome’s contraction rate was 60/min with power supply of 10V, 300mA for 100ms and run for 2 hours. Mean temperature on the RA was 39⫾1.5 °C. RA EF was 30% in baseline, 5% in AF and 22% in assisted AF conditions. Mean central venous pressure was 8⫾2mmHg in baseline, 15⫾6mmHg in AF and 12⫾5 mmHg in assisted AF conditions. Mean pulmonary artery pressure was 16⫾5mmHg, 15⫾6mmHg and 17⫾5mmHg respectively (p⫽0.5). CO was 5.3⫾0.3 l/min in baseline, 4.4⫾0.6 l/min in AF and 5.1⫾0.3 l/min in assisted AF status (p⬍0.01). Conclusions: Placed on the right side, the artificial muscle restores the AK and improves CO. In patients with end stage cardiac failure and permanent AF, if implanted on both sides, it would improve CO and possibly delay or even avoid complex surgical treatment such as VAD implantation or heart transplant. 715 Initial In Vivo Testing of a Self-Balancing Pulsatile Continuous Flow Total Artificial Heart L.A.R. Golding, K. Fukamachi, D.J. Horvath, A.L. Massiello, H. Fumoto, Y. Arakawa, J. Catanese, J.-F. Chen, N. Mielke, T. Horai Lerner Research Institute, Cleveland Clinic, Cleveland, OH
714 Biometal Artificial Muscle Restores Atrial Kick in a Permanent Atrial Fibrillation Animal Model and Could Represent a New Tool in the Treatment of End Stage Heart Failure P. Tozzi1, D. Hayoz2, F. Salchli3, L.K. von Segesser1 1CHUV, Lausanne, Switzerland; 2Hopital Cantonal de Fribourg, Fribourg, Switzerland; 3CETT, Yverdon-les-Bains, Switzerland Purpose: Half of the patients with end stage heart failure suffer from persistent atrial fibrillation (AF). Current AF treatment can control ventricular rhythm but often fails to restore the transport function of the atrium. Atrial kick (AK) accounts for 10 to 15% of the ventricle ejection fraction. Any device able to restore the AK should signifi-
Purpose: Acute Implants of a unique, new concept Continouos Flow Total Artificial Heart (CFTAH) were done to confirm passive self balancing of right/left pump flows. Methods and Materials: After the CFTAH was implanted in 2 calves, pump performance and hemodynamic parameters were recorded over the full range of pump operational speeds (2,000 to 3,000 rpm). A similar data set over the same speed range was acquired under a series of induced hemodynamic states created by varying circulating blood volume (CBV), systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR). Results: Atrial pressures remained within physiologic ranges (1 to 9 mm Hg) with increasing pump flows. The automatic speed control algorithm (a sensorless controller) calculated pump flow based on motor speed and power values and showed good correlation with measured and calculated values. In acute study CFTAH -1 the only conditions where the atrial balance criteria (LAP-RAP ⫽ ⫹10 to -10 mm Hg) were not met occurred at one instance of very high PVR (804 dyne䡠sec䡠cm-5), where LAP – RAP was -11 mm Hg and also at 2800 and 3000 rpm for the condition of high CBV (3 liters of saline infused), where LAP – RAP was ⫹11 and ⫹13 mm Hg respectively. The extent of SVR and PVR relationships tested is shown with the normal range of values for SVR and PVR shown by the enclosed box. Conclusions: These acute studies demonstrated: 1. Accurate estimation of pump flow and SVR values calculated by the physiologic controller from only motor speed and current feedback 2. Passive self regulation of flows and pressures was demonstrated by atrial pressure balancing in response to altered physiologic states of varying CBV, SVR, and PVR over the full range of pump operating speeds.
The Journal of Heart and Lung Transplantation Volume 28, Number 2S
Abstracts
S315
transplants. Further, the long-term impact of the resulting increased ischemic time on survival and the added cost of procurement that resulted from TAC should be quantified to assess the full effect of TAC outcomes. Heart transplantation before and after 2006 UNOS allocation change. Transplants before allocation change (2 years) n ⴝ 80 1. Candidate Status 1A 1B 2 2. Waiting time (mean, days) 3. Ischemic time (mean, min) 4. Imported donor heart 5. Thirty-day mortality
19 16 45 89
(24%) (20%) (56%)
198
Transplants after allocation change (2 years) n ⴝ 70
30(43%) 23(33%) 17(24%) 71 222
P value
0.01 0.06 0.0001 0.46 0.04
43
(54%)
46(66%)
0.18
76
(95%)
68(97%)
0.70
P ⬍ 0.05 for statistical significance
717 Predictors of Time on the Lung Transplant Waiting List after Implementation of the Lung Allocation Score (LAS) D. Hadjiliadis1, J. Munson1, V.N. Ahya1, J. Lee1, R.M. Kotloff1, A. Pochettino2, J.D. Christie1 1University of Pennsylvania, Philadelphia, PA; 2University of Pennsylvania, Philadelphia, PA
716 The Impact of 2006 United Network for Organ Sharing Thoracic Organ Allocation Policy Change: Mission Accomplished? J.N. Nativi1, A.G. Kfoury1, C. Myrick2, M. Peters2, D. Renlund1, P. Fisher1, E. Gilbert1, F. Bader1, A. Singhal1, D. Bull1, M. Everitt1, J. Stehlik1 1UTAH Cardiac Transplant Program, Salt Lake City, UT; 2Intermountain Donor Services, Salt Lake City, UT Purpose: United Network for Organ Sharing (UNOS) thoracic organ allocation change (TAC) in 2006 intended to reduce deaths on waiting list by expanding regional organ sharing. As such, organs would be allocated to the sickest recipients with higher listing status. Our aim was to determine the impact of TAC on a program with a historically higher proportion of status 2 heart transplants. Methods and Materials: We compared procurement activity (OPO data) and heart transplant activity within the UTAH Cardiac Transplant Program for two years before and two years after the TAC. Results: TAC resulted in a dramatic decrease in status 2 transplants accompanied by increase in status 1A transplants, with a nonsignificant decrease in the waiting time. A higher number of donor organs were imported after TAC, which resulted in a significant increase in ischemic time (table). There was no significant difference in the mortality on the waiting list (6% vs 5%, p ⫽ 0.76) and the short-term post-transplant survival was similar. Conclusions: The expanded regional sharing from TAC resulted in less status 2 patients being transplanted in favor of an increase of status 1A
Purpose: A prior single center study has suggested that LAS, recipient height and type of transplant received are all significant predictors of time on the waiting list for patients awaiting lung transplantation, since LAS implementation. However, national studies to assess these findings are lacking. A study utilizing United Network of Organ Sharing (UNOS) data was undertaken to answer these questions. Methods and Materials: Waiting list data from UNOS were obtained for patients transplanted from 5/4/05 to 2/1/08. Demographic data, including recipient height were obtained. In addition, UNOS region of transplant, blood group and LAS at the time of transplant were collected. Multivariable linear regression analysis was utilized to identify predictors of time on the waiting list. Results: There were 4041 transplant recipients during the study period. Their baseline characteristics are seen in the table. On multivariable analysis LAS score and height had a significantly inverse relationship with time on the waiting list, while receipt of a double lung transplant resulted in a significant increase of time on the waiting list: LAS p⬍0.001; height p⫽0.035; bilateral transplant p⫽0.002. When blood groups were added to the model, the results remained significant and blood group O was associated with longer times on the waiting list (p⫽0.008). Finally, when region of UNOS was included in the model, height lost its significance, while type of transplant and LAS remained significant predictors of waiting list time. Seven regions had significantly different waiting times, five longer and two shorter than average. Conclusions: LAS score and type of transplant influence time spent on the waiting list. Height might play a role in certain UNOS regions. Baseline characteristics LAS Height (m) Age Gender (male) Type of transplant (bilateral) Blood group A O AB B
41.9⫾13.6(iqrange:33.6-44.4) 1.68⫾0.15 (iq range: 1.63-1.77) 52.5⫾13.0 (iq range: 46-62) 2300 (56.9%) 2491 (62.9%) 1633 (40.4%) 1806 (44.7%) 176 (4.4%) 424 (10.5%)