- Email: [email protected]
Intermittent Low Speed Software (ILS) May Reduce the Prevalence of De Novo Aortic Insufficiency in Patients Supported With HeartWare HVAD Pump
S154
The Journal of Heart and Lung Transplantation, Vol 34, No 4S, April 2015
3( 99) Changes in Aortic Wall Structure, Composition, and Stiffness With Continuous-Flow Left Ventricular Assist Devices A.V. Ambardekar ,1 R.B. Dodson,2 K.S. Hunter,3 A.N. Babu,4 R.M. Tuder,5 J. Lindenfeld.1 1Medicine-Cardiology, University of Colorado, Aurora, CO; 2Bioengineering and Pediatric Surgery, University of Colorado, Aurora, CO; 3Bioengineering and Pediatrics-Cardiology, University of Colorado, Aurora, CO; 4Cardiothoracic Surgery, University of Colorado, Aurora, CO; 5Medicine-Pulmonary, University of Colorado, Aurora, CO. Purpose: The effects of non-pulsatile blood flow on the structure, composition, and resultant stiffness of the aorta have not been studied. The goal of this study was to examine the histologic ultrastructure of the aorta from patients supported with continuous-flow left ventricular assist devices (CF-LVADs) and assess for corresponding changes in direct measures of aortic wall composition and stiffness. Methods: Age-matched aortic wall tissue samples were collected from consecutive patients with heart failure (HF) at the time of cardiac transplantation and compared to nonfailing donor hearts. An unbiased stereological approach was used to quantify aortic wall morphometry and composition. In addition, aortic samples were biomechanically tested to determine the stress-strain relationship of the vessel. Results: Data were obtained from 4 patients who were not supported with a LVAD (HF group, average age of 58.3±8.0 years), 7 patients who were supported with a CF-LVAD with no aortic valve opening (HF+LVAD group, average age 57.7±5.6 years), and 3 nonfailing donors (average age 53.3±12.9 years). Compared to HF patients, the aortic walls from HF+LVAD patients had an increase in wall thickness (2014±294 vs. 1566±119 µm, p= 0.007), collagen content (38.9±3.7% vs. 26.7±11.7%, p= 0.039), and smooth muscle content (39.7±3.2% vs. 27.1±1.6% vs. p< 0.001) accompanied by a reduction in elastin content (18.9±4.3% vs. 34.0±5.4%, p= 0.001) and mucinous ground-substance content (2.5±1.8% vs. 12.2±8.0%, p= 0.019). Stress-strain curves from the aortic wall samples revealed increased vessel stiffness in HF+LVAD samples compared to HF and nonfailing samples. The physiological modulus of the aorta progressively stiffened from 74.3±5.5 kPa in the nonfailing to 134.4±35.0 kPa in the HF to 201.7±36.4 kPa in the HF+LVAD groups (p< 0.001). Conclusion: Among patients supported with CF-LVADs and no aortic valve opening, there are changes in the structure and composition of the aortic wall compared to age-matched HF patients and nonfailing donors. These changes are accompanied by an increase in aortic wall stiffness. As the number of patients with chronic CF-LVADs increase, further studies examining the role of non-pulsatile blood flow on aortic vascular function and the potential resultant systemic sequelae are needed. 4( 00) Quantification of Aortic Insufficiency in Patients With Left Ventricular Assist Devices: A Novel Approach Combining Invasive Hemodynamics and Echocardiography J. Grinstein ,1 E. Kruse,1 G. Sayer,1 S. Fedson,1 G.H. Kim,1 U.P. Jorde,2 C. Juricek,3 T. Ota,3 V. Jeevanandam,3 R.M. Lang,1 N. Uriel.1 1Medicine, University of Chicago Medical Center, Chicago, IL; 2Medicine, Montefiore Medical Center, New York, NY; 3Surgery, University of Chicago Medical Center, Chicago, IL. Purpose: Aortic insufficiency (AI) is common following continuous flow left ventricular assist device (CF-LVAD). Echocardiographic evaluations alone do not take into account the pan-cyclical nature and unique flow properties of AI in CF-LVAD patients. A novel method that can measure regurgitant flow throughout the entirety of the cardiac cycle may better reflect the degree of AI in CF-LVAD patients. Methods: In this prospective study, LVAD patients with varying degrees of AI underwent simultaneous right heart catheterization (RHC) and transthoracic echocardiogram (TTE). Regurgitant fraction (RF) across the aortic valve was calculated by subtracting the cardiac output obtained by RHC from the total systemic flow (TSF) measured using TTE. TSF was calculated by measuring the velocity time integral (VTI) and cross sectional area of the LVAD outflow cannula and left ventricular outflow tract (LVOT) (Eq-1). The RFs were compared to traditional TTE grading and results were clinically compared to left-sided filling pressures obtained during RHC. Results: Patients without TTE evidence of AI had a RF approaching zero (0.6% +/− 6.8%). Patients with visually estimated trace AI on TTE had a
RF of 32.8% +/− 5.5% which corresponds with the low range of moderate AI according to TTE guidelines. Patients with mild AI had a RF of 34.4% +/− 0.9% that similarly corresponds with the low range of moderate AI. The RF of patients with visually moderate AI was significantly higher (43.9% +/− 2.7%) and corresponds with the high range of moderate AI. (Fig-1A). Clinically, RF correlates more strongly with the pulmonary capillary wedge pressure (PCWP) than vena contracta (R2 0.65 vs. 0.46) (Fig-1B) in all patients with AI. Conclusion: RF measured by simultaneous RHC and TTE over the entirety of the cardiac cycle better correlates with clinical filling pressures than TTE parameters and may identify important AI that might be underestimated using conventional TTE alone.
4( 01) Intermittent Low Speed Software (ILS) May Reduce the Prevalence of De Novo Aortic Insufficiency in Patients Supported With HeartWare HVAD Pump D. Saeed ,1 R. Westenfeld,2 A. Albert,1 B. Maxhera,1 S. Keymel,2 U. Boeken,1 A. Lichtenberg.1 1Cardiovascular Surgery, Heinrich-Heine University Dusseldorf, Dusseldorf, Germany; 2Division of Cardiology, Pulmonology, and Vascular Medicine, Heinrich-Heine University Dusseldorf, Dusseldorf, Germany. Purpose: De novo aortic valve insufficiency (AI) is a frequent occurrence (range 11-42%) in patients supported with the HeartMate II left ventricular assist device (LVAD). Consistent closure of the aortic valve is among the main known risk factors for AI development. The European version of the HeartWare HVAD (HeartWare, Framingham, MA) has an intermittent low speed (ILS) software to facilitate intermittent aorten valve (AV) opening; this software is not approved in the US. We examined AV opening status and prevalence of AI in patients supported with HeartWare HVAD. We hypothesize that ILS activation may reduce the incidence of AI in HeartWare patients. Methods: HeartWare HVAD patients were prospectively monitored using serial echocardiograms (echo) at different time points following the LVAD implantation. Inclusion criteria were patients with no > mild AI and/or aortic valve surgery (AVS) at the time of LVAD implantation and at least 60 days of support. AI jet width > 25% in the parasternal long axis defined > mild AI. AV opening of at least 3/10 beats defined AV opening excluding AV openings that occurred during the low speed phase. The ILS was activated in all patients about 2 weeks after LVAD implantation. Results: Three of 34 patients had AVS and were excluded from the analysis. A total of 31 patients with mean age of 57± 13 yo met the inclusion criteria. The median support duration at the time of the latest echo was 350 days (661250 days). Four patients developed trace AI (13%) and 2 patients had mild AI (6%). An average pump flow and speed of 4,4 ± 0,8 L/min and 2574 ± 156 rpm respectively were documented at the time of the latest echo. AV opening was seen in all except for 1 patient. It is noteworthy that one patient developed moderate AI after 6 months of support and was treated conservatively (antihypertensive therapy). This patient had merely mild AI later in follow up. Conclusion: AV opening is frequent and the development of AI seems to be rare in patients supported with HeartWare HVAD. The activation of ILS software may explain this finding. 4( 02) Withdrawn
The Journal of Heart and Lung Transplantation, Vol 34, No 4S, April 2015
3( 99) Changes in Aortic Wall Structure, Composition, and Stiffness With Continuous-Flow Left Ventricular Assist Devices A.V. Ambardekar ,1 R.B. Dodson,2 K.S. Hunter,3 A.N. Babu,4 R.M. Tuder,5 J. Lindenfeld.1 1Medicine-Cardiology, University of Colorado, Aurora, CO; 2Bioengineering and Pediatric Surgery, University of Colorado, Aurora, CO; 3Bioengineering and Pediatrics-Cardiology, University of Colorado, Aurora, CO; 4Cardiothoracic Surgery, University of Colorado, Aurora, CO; 5Medicine-Pulmonary, University of Colorado, Aurora, CO. Purpose: The effects of non-pulsatile blood flow on the structure, composition, and resultant stiffness of the aorta have not been studied. The goal of this study was to examine the histologic ultrastructure of the aorta from patients supported with continuous-flow left ventricular assist devices (CF-LVADs) and assess for corresponding changes in direct measures of aortic wall composition and stiffness. Methods: Age-matched aortic wall tissue samples were collected from consecutive patients with heart failure (HF) at the time of cardiac transplantation and compared to nonfailing donor hearts. An unbiased stereological approach was used to quantify aortic wall morphometry and composition. In addition, aortic samples were biomechanically tested to determine the stress-strain relationship of the vessel. Results: Data were obtained from 4 patients who were not supported with a LVAD (HF group, average age of 58.3±8.0 years), 7 patients who were supported with a CF-LVAD with no aortic valve opening (HF+LVAD group, average age 57.7±5.6 years), and 3 nonfailing donors (average age 53.3±12.9 years). Compared to HF patients, the aortic walls from HF+LVAD patients had an increase in wall thickness (2014±294 vs. 1566±119 µm, p= 0.007), collagen content (38.9±3.7% vs. 26.7±11.7%, p= 0.039), and smooth muscle content (39.7±3.2% vs. 27.1±1.6% vs. p< 0.001) accompanied by a reduction in elastin content (18.9±4.3% vs. 34.0±5.4%, p= 0.001) and mucinous ground-substance content (2.5±1.8% vs. 12.2±8.0%, p= 0.019). Stress-strain curves from the aortic wall samples revealed increased vessel stiffness in HF+LVAD samples compared to HF and nonfailing samples. The physiological modulus of the aorta progressively stiffened from 74.3±5.5 kPa in the nonfailing to 134.4±35.0 kPa in the HF to 201.7±36.4 kPa in the HF+LVAD groups (p< 0.001). Conclusion: Among patients supported with CF-LVADs and no aortic valve opening, there are changes in the structure and composition of the aortic wall compared to age-matched HF patients and nonfailing donors. These changes are accompanied by an increase in aortic wall stiffness. As the number of patients with chronic CF-LVADs increase, further studies examining the role of non-pulsatile blood flow on aortic vascular function and the potential resultant systemic sequelae are needed. 4( 00) Quantification of Aortic Insufficiency in Patients With Left Ventricular Assist Devices: A Novel Approach Combining Invasive Hemodynamics and Echocardiography J. Grinstein ,1 E. Kruse,1 G. Sayer,1 S. Fedson,1 G.H. Kim,1 U.P. Jorde,2 C. Juricek,3 T. Ota,3 V. Jeevanandam,3 R.M. Lang,1 N. Uriel.1 1Medicine, University of Chicago Medical Center, Chicago, IL; 2Medicine, Montefiore Medical Center, New York, NY; 3Surgery, University of Chicago Medical Center, Chicago, IL. Purpose: Aortic insufficiency (AI) is common following continuous flow left ventricular assist device (CF-LVAD). Echocardiographic evaluations alone do not take into account the pan-cyclical nature and unique flow properties of AI in CF-LVAD patients. A novel method that can measure regurgitant flow throughout the entirety of the cardiac cycle may better reflect the degree of AI in CF-LVAD patients. Methods: In this prospective study, LVAD patients with varying degrees of AI underwent simultaneous right heart catheterization (RHC) and transthoracic echocardiogram (TTE). Regurgitant fraction (RF) across the aortic valve was calculated by subtracting the cardiac output obtained by RHC from the total systemic flow (TSF) measured using TTE. TSF was calculated by measuring the velocity time integral (VTI) and cross sectional area of the LVAD outflow cannula and left ventricular outflow tract (LVOT) (Eq-1). The RFs were compared to traditional TTE grading and results were clinically compared to left-sided filling pressures obtained during RHC. Results: Patients without TTE evidence of AI had a RF approaching zero (0.6% +/− 6.8%). Patients with visually estimated trace AI on TTE had a
RF of 32.8% +/− 5.5% which corresponds with the low range of moderate AI according to TTE guidelines. Patients with mild AI had a RF of 34.4% +/− 0.9% that similarly corresponds with the low range of moderate AI. The RF of patients with visually moderate AI was significantly higher (43.9% +/− 2.7%) and corresponds with the high range of moderate AI. (Fig-1A). Clinically, RF correlates more strongly with the pulmonary capillary wedge pressure (PCWP) than vena contracta (R2 0.65 vs. 0.46) (Fig-1B) in all patients with AI. Conclusion: RF measured by simultaneous RHC and TTE over the entirety of the cardiac cycle better correlates with clinical filling pressures than TTE parameters and may identify important AI that might be underestimated using conventional TTE alone.
4( 01) Intermittent Low Speed Software (ILS) May Reduce the Prevalence of De Novo Aortic Insufficiency in Patients Supported With HeartWare HVAD Pump D. Saeed ,1 R. Westenfeld,2 A. Albert,1 B. Maxhera,1 S. Keymel,2 U. Boeken,1 A. Lichtenberg.1 1Cardiovascular Surgery, Heinrich-Heine University Dusseldorf, Dusseldorf, Germany; 2Division of Cardiology, Pulmonology, and Vascular Medicine, Heinrich-Heine University Dusseldorf, Dusseldorf, Germany. Purpose: De novo aortic valve insufficiency (AI) is a frequent occurrence (range 11-42%) in patients supported with the HeartMate II left ventricular assist device (LVAD). Consistent closure of the aortic valve is among the main known risk factors for AI development. The European version of the HeartWare HVAD (HeartWare, Framingham, MA) has an intermittent low speed (ILS) software to facilitate intermittent aorten valve (AV) opening; this software is not approved in the US. We examined AV opening status and prevalence of AI in patients supported with HeartWare HVAD. We hypothesize that ILS activation may reduce the incidence of AI in HeartWare patients. Methods: HeartWare HVAD patients were prospectively monitored using serial echocardiograms (echo) at different time points following the LVAD implantation. Inclusion criteria were patients with no > mild AI and/or aortic valve surgery (AVS) at the time of LVAD implantation and at least 60 days of support. AI jet width > 25% in the parasternal long axis defined > mild AI. AV opening of at least 3/10 beats defined AV opening excluding AV openings that occurred during the low speed phase. The ILS was activated in all patients about 2 weeks after LVAD implantation. Results: Three of 34 patients had AVS and were excluded from the analysis. A total of 31 patients with mean age of 57± 13 yo met the inclusion criteria. The median support duration at the time of the latest echo was 350 days (661250 days). Four patients developed trace AI (13%) and 2 patients had mild AI (6%). An average pump flow and speed of 4,4 ± 0,8 L/min and 2574 ± 156 rpm respectively were documented at the time of the latest echo. AV opening was seen in all except for 1 patient. It is noteworthy that one patient developed moderate AI after 6 months of support and was treated conservatively (antihypertensive therapy). This patient had merely mild AI later in follow up. Conclusion: AV opening is frequent and the development of AI seems to be rare in patients supported with HeartWare HVAD. The activation of ILS software may explain this finding. 4( 02) Withdrawn