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Telemetry Capable, Implantable Pulsatile Controller (IPC) for Left Ventricular Assist Devices (LVAD)
S62 Journal of Cardiac Failure Vol. 19 No. 8S August 2013 the incidence and mechanism are not known. Hypothesis: The mechanism of RV lead malfunction following LVAD implantation may be related to changes in LV and RV geometry, rather than decrease in LV mass. Methods: In this prospective single center study, we collected ICD lead data before, during and after LVAD implantation, including 12 time points during implantation. Results: Data were collected prospectively on 29 patients, including 24 patients undergoing LVAD implantation (ICD implanted 35634.9 months earlier) and 5 control patients who had LVAD implanted initially followed by ICD implantation. Of the 24 LVAD patients, 17 were male, 15 had coronary artery disease, 15 had LVAD implanted as destination therapy, and mean age was 57.6613 years. Fifty-four leads were tested before, during, 1 week and 3 months after LVAD implantation, including 18 right atrial, 24 right ventricular (RV), and 12 left ventricular (LV) leads. In 16 patients, ICD leads were tested at 12 intraoperative steps. RV sensing was O50% decreased from baseline in 6 patients (25%) immediately post-op, with RV sensing improving at 1 week in 3 patients (50%). In 2 patients (8%) who also had decreased sensing, RV pacing threshold was O50% elevated from baseline immediately post-op (n51) and at 1 week (n51). One RV pacing threshold returned to baseline at 3 months. Of the 4 patients with significant decreases in RV sensing in whom lead function was tested at serial time points during VAD implantation, an RV sensing decrease was not detected until immediately following weaning off cardiopulmonary bypass. One RV lead was turned off and one was replaced due to non-capture. Time from lead implant to LVAD was 77.6657.9 months in the patients with decreased RV lead sensing (n56) vs. 33.3643 months in patients with no decreased RV sensing (n518). Post-operatively, 14 (58%) patients had ventricular arrhythmias, new onset in 8 (33%); and 15 (63%) had atrial arrhythmias, new onset in 7 (29%). On ECG, sensed QRS width decreased after LVAD (126.5636.7 vs. 100635.5ms). Of the 5 control patients, none had O50% decreased RV sensing and 1 had O50% elevation in pacing threshold from the day of implant to 1 year post-implant. Of 29 patients, 6 died (4.966.8 months) and 1 underwent cardiac transplant (3 months). Conclusions: ICD lead malfunction can occur following LVAD implantation, but may improve over time. Intraoperative RV sensing problems were not detected until weaning of cardiopulmonary bypass, suggesting the mechanism of RV lead malfunction may be related to changes in LV and RV geometry from LVAD implantation. Ventricular arrhythmias are common in the LVAD population, even in patients who did not have them pre-operatively.
178 Telemetry Capable, Implantable Pulsatile Controller (IPC) for Left Ventricular Assist Devices (LVAD) Sam Siavash Asgari, Pramod Bonde; Yale School of Medicine, New Haven, CT Introduction: Recent generations of continuous-flow LVADs require a transcutaneous driveline to conduct power, controller algorithms, and data between the pump and extracorporeal controller unit. Driveline associated infections are a common complication which impart significant negative impact on quality of life and increase medical cost of LVAD treatment. Furthermore, continuous flow circulation has been implicated in gastrointestinal bleeding, limited cardiac unloading, and aortic incompetence. Hypothesis: We have earlier demonstrated the feasibility of wireless energy transfer to power an LVAD controller. In the current investigation, we present an ultra-compact implantable controller (IPC) to entirely free patients from the LVAD driveline and considerably reduce the extracorporeal hardware and weight. Since physiological flow, especially in the patient category of destination therapy, is of significance, we have embedded a pulsatile algorithm in the IPC. Methods: The controller has been designed to drive an LVAD with required safety and back up measures. The IPC embraces a reliable wireless algorithm to communicate to an external platform based Graphical User Interface (GUI) embedded in an iPhone, iPad, or a computer. The controller couples to a receiver coil to wirelessly obtain power. Furthermore, we have employed signal processing methods to analyze an ECG signal and modulate the pump speed during systole and diastole for co/counter-pulsation or fixed mode operation. When used with ECG gating, the IPC allows on-demand customization of operation with instantaneous flow and RPM changes, resulting in a pulsatile flow with adjustable pulse pressure. Telemetry has also been achieved by an embedded antenna. Initially, the controller was
Figure 1. A&B show the HVAD and IPC; C&D show the smart platform; E&F show the in -vivo data; G&H show the in vitro results; I&J show high speed during systole and Diastole. respectively (ECG Gated).
tested with an HVAD and HMII in an in-vitro setup to test its reliability. Ultimately, the controller has been implanted in two animals to wirelessly drive an HVAD in continuous and pulsatile modes. Results: Our tests results prove the system to be remarkably safe, accurate and efficient. The IPC operated continuously for two weeks in a mock circulation loop and 3 hours in each animal experiment. We have demonstrated the versatility of a controller that can create physiological flow. In terms of efficiency, IPC consumes less power to obtain the same pump speed and flow rate as compared with the HVAD controller. Conclusions: The combination of wireless powering, communicating with a user-friendly GUI and a very small footprint makes this an ideal totally implantable LVAD system. Patients are therefore liberated from the risk of driveline infection and are able to shower, swim, and perform physical activities with improved hygiene and mobility.
179 A Multi-Modailty Approach to Antibody Mediated Rejection Steven Geier1, Hemant Parekh1, Yanhau Li1, Rene Alvarez2, Eman Hamad2, Emily Tsai2, James Fitzpatrick2, Lazaros Nikolaidis2, Mustafa Ahmed2; 1Temple University School of Medicine, Philadelphia, PA; 2Temple University School of Medicine, Philadelphia, PA Introduction: Antibody mediated rejection remains a difficult problem in orthotopic heart transplant recipients. Treatment with solitary therapeutic targets often result in incomplete success. We describe our experience using a multi-targeted therapeutic approach. Case: A 41 year-old female who underwent orthotopic heart transplantation in 2007 presented with signs and symptoms of heart failure. She was treated with high dose corticosteroids while awaiting results of endomyocardial biopsy, which reveled no cellular rejection, but C4d and C1q evidence for antibody mediated rejection. Multiple donor specific antibodies were identified. She was initially treated with plasmapharesis and rituximab. This resulted in clinical improvement, but no change in her serologic or immunohistochemical markers of AMR. Several weeks later, she presented with symptomatic bradycardia and hypotension, requiring dobutamine infusion for hemodynamic stability. Endomyocardial biopsy once again was C4d and C1q positive, and serum was noted to have multiple DSAs with elevated MFIs. She therefore was treated with a combination of plasmapharesis, IVIG, and subcutaneous bortezomib [Figure 1] which resulted in clinical stabilization and improvement in donor specific antibodies [Figure 2]. Conclusions: A combination, multi-targeted approach to antibody mediated rejection may prove to be more effective in regards to clinical improvement, and resolution of serologic and immunohistochemical markers of rejection. Additional study to define an optimal approach is required.
178 Telemetry Capable, Implantable Pulsatile Controller (IPC) for Left Ventricular Assist Devices (LVAD) Sam Siavash Asgari, Pramod Bonde; Yale School of Medicine, New Haven, CT Introduction: Recent generations of continuous-flow LVADs require a transcutaneous driveline to conduct power, controller algorithms, and data between the pump and extracorporeal controller unit. Driveline associated infections are a common complication which impart significant negative impact on quality of life and increase medical cost of LVAD treatment. Furthermore, continuous flow circulation has been implicated in gastrointestinal bleeding, limited cardiac unloading, and aortic incompetence. Hypothesis: We have earlier demonstrated the feasibility of wireless energy transfer to power an LVAD controller. In the current investigation, we present an ultra-compact implantable controller (IPC) to entirely free patients from the LVAD driveline and considerably reduce the extracorporeal hardware and weight. Since physiological flow, especially in the patient category of destination therapy, is of significance, we have embedded a pulsatile algorithm in the IPC. Methods: The controller has been designed to drive an LVAD with required safety and back up measures. The IPC embraces a reliable wireless algorithm to communicate to an external platform based Graphical User Interface (GUI) embedded in an iPhone, iPad, or a computer. The controller couples to a receiver coil to wirelessly obtain power. Furthermore, we have employed signal processing methods to analyze an ECG signal and modulate the pump speed during systole and diastole for co/counter-pulsation or fixed mode operation. When used with ECG gating, the IPC allows on-demand customization of operation with instantaneous flow and RPM changes, resulting in a pulsatile flow with adjustable pulse pressure. Telemetry has also been achieved by an embedded antenna. Initially, the controller was
Figure 1. A&B show the HVAD and IPC; C&D show the smart platform; E&F show the in -vivo data; G&H show the in vitro results; I&J show high speed during systole and Diastole. respectively (ECG Gated).
tested with an HVAD and HMII in an in-vitro setup to test its reliability. Ultimately, the controller has been implanted in two animals to wirelessly drive an HVAD in continuous and pulsatile modes. Results: Our tests results prove the system to be remarkably safe, accurate and efficient. The IPC operated continuously for two weeks in a mock circulation loop and 3 hours in each animal experiment. We have demonstrated the versatility of a controller that can create physiological flow. In terms of efficiency, IPC consumes less power to obtain the same pump speed and flow rate as compared with the HVAD controller. Conclusions: The combination of wireless powering, communicating with a user-friendly GUI and a very small footprint makes this an ideal totally implantable LVAD system. Patients are therefore liberated from the risk of driveline infection and are able to shower, swim, and perform physical activities with improved hygiene and mobility.
179 A Multi-Modailty Approach to Antibody Mediated Rejection Steven Geier1, Hemant Parekh1, Yanhau Li1, Rene Alvarez2, Eman Hamad2, Emily Tsai2, James Fitzpatrick2, Lazaros Nikolaidis2, Mustafa Ahmed2; 1Temple University School of Medicine, Philadelphia, PA; 2Temple University School of Medicine, Philadelphia, PA Introduction: Antibody mediated rejection remains a difficult problem in orthotopic heart transplant recipients. Treatment with solitary therapeutic targets often result in incomplete success. We describe our experience using a multi-targeted therapeutic approach. Case: A 41 year-old female who underwent orthotopic heart transplantation in 2007 presented with signs and symptoms of heart failure. She was treated with high dose corticosteroids while awaiting results of endomyocardial biopsy, which reveled no cellular rejection, but C4d and C1q evidence for antibody mediated rejection. Multiple donor specific antibodies were identified. She was initially treated with plasmapharesis and rituximab. This resulted in clinical improvement, but no change in her serologic or immunohistochemical markers of AMR. Several weeks later, she presented with symptomatic bradycardia and hypotension, requiring dobutamine infusion for hemodynamic stability. Endomyocardial biopsy once again was C4d and C1q positive, and serum was noted to have multiple DSAs with elevated MFIs. She therefore was treated with a combination of plasmapharesis, IVIG, and subcutaneous bortezomib [Figure 1] which resulted in clinical stabilization and improvement in donor specific antibodies [Figure 2]. Conclusions: A combination, multi-targeted approach to antibody mediated rejection may prove to be more effective in regards to clinical improvement, and resolution of serologic and immunohistochemical markers of rejection. Additional study to define an optimal approach is required.