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Hemodynamic Effects of Intra-Aortic Balloon Counterpulsation in Patients with Advanced Heart Failure
S38 Journal of Cardiac Failure Vol. 21 No. 8S August 2015 (EF) was 57.9 6 10.6%. The BB group had a mean NYHA Class of 1.43 60.63, number of hospitalizations were 2.20 6 3.61 (range 0 to 18) and EF was 61.6 6 7.5%. There was no significant difference between the two groups in mortality (p50.13) and number of hospitalizations (p50.44). Conclusion: In this single center analysis, beta blocker use in heart transplant patients appeared safe and did not affect functional status, mortality or number of hospitalizations in comparison to the nonBB group.
067 Reversibility of Restrictive Pulmonary Function Post Cardiac Transplantation Carolyn M. Rosner, Gurusher Panjrath, Ramesh Singh, Shashank S. Desai, Anthony J. Rongione; Inova Health System, Falls Church, VA Background: Pulmonary function testing is an essential component of cardiac transplant evaluation. Severe pulmonary limitations are a contraindication to listing. Dilated cardiomyopathy and pulmonary edema can have a significant impact, causing restrictive but possibly reversible changes in pulmonary function tests (PFT’s). Effect of cardiac transplantation on PFT is not clear. We compared the resting pulmonary function in patients with end-stage cardiomyopathy prior to and shortly after cardiac transplantation. Methods: Seventy-six patients underwent orthotopic heart transplant between January 2009 and June 2013. PFT’s performed prior to cardiac transplant were compared to those obtained 3 months post transplant. Patients who did not have pre and post transplant spirometry, one patient with pulmonary sarcoidosis and one patient who underwent heart-lung transplant were excluded from this analysis. Fifty-one patients were included in this analysis. Results: There was a significant increase in both FEV1 and FVC in a short time after cardiac transplant. There was not a significant change in the FEV1/FVC ratio. Conclusion: In patients without intrinsic lung disease, end-stage cardiomyopathy results in significant, reversible limitations in pulmonary function. Improvements in pulmonary function are seen in the majority of transplant recipients as soon as 3 months post transplant. This important finding should be taken into consideration when evaluating candidates for cardiac transplantation. Table 1. Baseline Characteristics at Time of Transplant Listing
Age (years) Gender (% male, n) Diagnosis (% ICM, n) BMI Previous sternotomy (average number) History of smoking (%, n) Average # of pack years Amiodarone use (current) Pulmonary Bronchodilator use (current) Inhaled Corticosteroid (current) Previous diagnosis of lung disease
54.8 69% 37% 27.2 0.5 47% 8.8 29% 4% 2% 12%
(35) (19)
(24) (15) (2) (1) (6)
dysfunction (46% vs. 19%, p50.036) and higher MELD scores (17 6 5 vs. 13 6 6, p50.028). On average, the first GI bleeding event occurred after 112 6 65 days, and 45% of patients had recurrent GI bleeding episodes (mean 2 6 1 episode per patient). Most patients (9/11) had their first GI bleeding episodes within 4 months post implant. We examined pump management (rpm, flow), average of last 4 INRs and mean arterial pressures (MAP), aortic valve opening and right ventricular (RV) dysfunction (O moderate RV enlargement or TAPSE ! 15 mm on echo) prior to the first GI bleeding and compared to a similar time period (first 4 months post implant) in patients without GI bleeding. There were no differences in speed (9100 6 300 vs. 8900 6 200 rpm for HMII; 2600 6 160 vs. 2600 6 130 rpm for HVAD), flow (5 6 0.5 vs. 4.8 6 0.3 L/min for HM II; 4.6 6 0.3 vs. 5.1 6 0.4 L/ min for HVAD), INR (2 6 0.4 vs. 2.3 6 1), MAP (77 6 9 vs. 78 6 7 mmHg), aspirin use (67% vs. 69%), aortic valve opening (36% vs. 34%) and RV dysfunction (45% vs. 48%) between the two groups. Pre implant liver dysfunction emerged as independent risk factor for subsequent GI bleeding (HR 1.22, 95% CI 1.1 - 1.5). Conclusions: Pre-implant liver dysfunction was associated with subsequent GI bleeding in VAD patients. These findings need to be explored in a larger cohort.
069 Hemodynamic Effects of Intra-Aortic Balloon Counterpulsation in Patients with Advanced Heart Failure Lyanne Buiten, Vikram Paruchuri, Duc Thinh Pham, Michael Kiernan, David DeNofrio, Carey Kimmelstiel, Navin K. Kapur; Tufts Medical Center, Boston, MA Introduction: Intra-aortic balloon counterpulsation pump (IABP) therapy reduces LV afterload by displacing blood volume in the descending aorta during diastole. Recent clinical trials have questioned the utility of IABP therapy in acute myocardial infarction. No studies have examined the clinical utility of IABP therapy in patients with advanced heart failure. The objective of this study is to quantify the hemodynamic effect of IABPs in patients with advanced heart failure. Methods: In this ongoing prospective single-arm study we enrolled 5 patients to date with Stage C/D, NYHA Class III/IV heart failure. After providing informed consent, baseline hemodynamics were acquired with a pulmonary artery catheter and LV conductance catheter. A 50cc IABP was then inserted and activated at full capacity for 15 minutes, then turned off. After a 15 minute period of recovery to baseline, the same 50cc IABP was activated with only 40cc of displacement volume for an additional 15 minutes. After study completion, the IABP was reactivated at full capacity. Results: Mean age of the study population was 53617 years with an LV ejection fraction of 1368%. LV stroke work was significantly reduced with 50cc (12476324 vs 7976239 mmHg mL, 50cc-IABP Off vs On, p!0.04; Figure 1), not with 40cc of volume displacement (13326238 vs 10546187 mmHg mL, 40cc-IABP Off vs On, p5NS). Compared to pre-activation values, no change in arterial elastance, stroke volume, end-systolic or end-diastolic pressures were observed with either device activated. Aortic diastolic pressure was significantly increased with 50cc (7168 vs 104614 mmHg, 50cc-IABP Off vs On, p!0.01) and 40cc (69610 vs 100610 mmHg, 40cc-IABP Off vs On, p!0.01) of volume displacement. No difference between 50cc and 40cc of volume displacement were observed. Conclusion: This is the first use of pressure-volume loop analysis
Table 2. Results
FEV1 FVC FEV1/FVC ratio
Pre transplant
Post transplant
% change
p
2.04 6 0.6 2.82 6 0.8 0.73 6 0.1
2.32 6 0.6 3.08 6 0.8 0.78 6 0.2
+13% +9% +7%
!0.01 !0.01 0.07
068 The Relation Between Liver Dysfunction and Gastrointestinal Bleeding in Patients with Ventricular Assist Devices David Lowe, Georg Wieselthaler, Liviu Klein; UCSF, San Francisco, CA Purpose: Gastrointestinal (GI) bleeding is a major comorbidity in patients with ventricular assist devices (VAD). It is unknown if pre-implant liver dysfunction is implicated in this pathophysiology. Methods: In 69 bridge-to-transplant (BTT) and destination therapy (DT) patients with HeartWare (HVAD) and HeartMate II VAD (HMII) we analyzed the relation between pre-implant liver dysfunction (cirrhotic appearance or portal hypertension on ultrasound, or MELD score O 20) and subsequent GI bleeding. Results: There were 11 patients (16%) with GI bleeding. These patients were older (62 6 7 vs. 56 6 16 yrs, p50.033) and more likely to have ischemic etiology (82% vs. 45%, p50.024) than patients without GI bleeding. There was no difference in women (18% vs. 14%), INTERMACS profile (2.1 6 1 vs. 2.4 6 1), NYHA class (3.5 6 0.4 vs. 3.4 6 0.5), ejection fraction (0.21 6 0.09 vs. 0.24 6 0.07), or days on device (363 6 283 vs. 275 6 268 days) between groups. Patients with GI bleeding had higher incidence of pre-implant liver
Figure 1.
The 19th Annual Scientific Meeting to study the effects of IABP therapy in patients with advanced heart failure. Initial observations suggest that larger capacity IABP activation reduces LV stroke work in patients with advanced heart failure. The study is actively enrolling through 2015.
070 Elevated Right Atrial Pressure Predicts Post Heart Transplant Outcomes Carolyn M. Rosner, Anthony J. Rongione, Gurusher Panjrath, Palak Shah, Shashank S. Desai, Ramesh Singh; Inova Health System, Falls Church, VA Background: Orthotopic heart transplantation (OHT) is the definitive treatment for end stage heart failure. Patient selection is key in improving post OHT outcomes. Pre-operative right ventricular dysfunction is associated with worse outcomes after mechanical circulatory support but its effect on post OHT outcomes has not been well described. Right atrial (RA) pressure is commonly used as a surrogate for RV function. We compared post OHT outcomes in patients with and without preoperative elevated RA pressure. Methods: An analysis of 124 patients who underwent isolated OHT at our institution from January 2008-October 2014 was performed. Patients undergoing re-transplantation were excluded. One hundred seventeen patients were included in this analysis. Groups were divided based on preoperative RA pressure. Baseline characteristics and post OHT outcomes (post OHT length of stay; 30 day, 1 year and 3 year survival and clinically significant rejection in the 1st year) were compared. Results: Pre OHT characteristics were similar between the 2 groups except for a difference in age and PVR, as shown in Table 1. Post heart transplant survival was worse in the group with pre transplant RA pressure O15mmHg, as shown in Table 2. Conclusion: Pre-operative elevated RA pressure was associated with a worse short and intermediate term (1 and 3 year) survival after OHT. There was no difference in post transplant rejection in the first year. Possible factors for poor survival include underestimation of pulmonary hypertension or organ dysfunction. RA pressures are readily available and may allow for a more accurate prediction of post OHT outcomes.
Table 1. Baseline Characteristics at Time of Transplant
Age Gender (% male) Diagnosis (%ICM) BMI Previous sternotomy Mechanical circulatory support LVAD/BiVAD/TAH ECMO IABP None UNOS status 1A at time of transplant Wait time to transplant (days) RA RVSWI (PAM-CVP) PVR TPG CO
Group A (N594) RA ! 15mmHg
Group B (N523) RA $ 15mmHg
55 73% 38% 27.3 82% 72%
48 70% 30% 28.3 78% 61%
62/4/1 1 0 26 77%
11/2/0 1 0 9 91%
255.4 6 235.2 7.1 6 3.9 13.3 6 6.8
209.3 6 219.2 18.0 6 3.3 13.6 6 8.1
0.40
1.9 6 1.2 8.5 6 4.6 4.7 6 1.2
2.5 6 1.5 9.5 6 3.8 5.1 6 3.8
0.03 0.35 0.60
p 0.02 0.71 0.50 0.37 0.69 0.28
Post transplant LOS (days) 30 day survival 1 year survival 3 year survival Incidence of rejection in the 1st year
18.6 98% 92% 86% 36%
Group B (N523) RA $ 15 17.7 83% 67% 50% 32%
HFSA
S39
071 VNS Does Not Reduce Heart Failure Progression in a Canine High Rate Pacing Model of HF Avram Scheiner; Medtronic, Mounds Veiw, MN Background: There is a significant unmet clinical need for effective therapies for heart failure (HF) patients. One potential therapeutic approach is Vagal Nerve Stimulation (VNS) in which a lead is placed on the cervical portion of the vagus nerve and stimulated using high frequency pulses. Multiple preclinical laboratories have published positive studies using this technique for HF treatment. This study attempts to duplicate one of these studies.1 Method: Sixteen dogs were implanted with a bipolar cuff lead (Inspire Medical Systems, Model 4063) placed on the cervical vagus nerve and connected to a nerve stimulator. A pacemaker was implanted with leads in the RA and in the RV for high rate Pacing (HRP). At post-operative week 2, each animal was randomized into either the control or VNS test group. HRP was started at week 2 in all animals to induce HF. VNS therapy was initiated at week 2 in the test group. For the VNS test group, VNS therapy was cycled continuously at 14 seconds on-12 seconds off. VNS therapy settings were at a frequency of 19 hertz and pulse width of 450 mseconds. Therapy was adjusted just below the level of coughing threshold for chronic VNS delivery. For each animal a series of weekly awake monitors were performed to ensure system integrity and therapy delivery. Echo measurements, ECG and blood samples were taken 2 weeks post-op at the initiation of high rate pacing, and again at weeks 6 and 10. The echo technician was blinded to each animal’s randomization assignment. The primary parameters of interest of the study were echo measures of remodeling and cardiac function. Secondary measures included various plasma biomarkers and post mortem heart size and weight and histological measurements. Results: The results of this study indicate that VNS does not produce a therapeutic effect in this high rate pacing HF canine model. The VNS treatment arm showed no significant difference compared to the control group in the primary endpoints in this study from randomization to 6 weeks or 10 weeks (EF, p5 0.60 and 0.83, EDV, p5 0.75 and 0.53 or ESV p5 0.90 and 0.63). A comparison of the primary endpoints of the control groups in this study and the previous published study1 suggests that similar changes were produced by the HRP model in both studies. Secondary measures of plasma biomarkers also showed no statistical differences between control and treatment arms at 6 and 10 weeks. Pathological findings showed no statistical difference in heart dimensions and weight. Conclusions: Although the canine HF model and VNS therapy technique were duplicated as done in the published positive VNS study, different results are seen. The results of this study indicate that VNS does not produce a therapeutic effect in this high rate pacing HF canine model. 1 Youhua Zhang, et al., “Chronic Vagus Nerve Stimulation Improves Autonomic Control and Attenuates Systemic Inflammation and Heart Failure Progression in a Canine High Rate Pacing Model” Circ Heart Fail published online Sep 22, 2009; DOI: 10.1161/CIRCHEARTFAILURE.109.873968
072 Early Elevated Pump Power and Associated Hemolysis Amongst HeartMate II Left Ventricular Assist Devices Anjan Tibrewala, Michael Nassif, David Raymer, Justin Vader, Shane LaRue, Scott Silvestry, Greg Ewald; Washington University, St. Louis, MO
0.12
!0.0001 0.88
Background: Continuous-flow left ventricular assist devices (CF-LVAD) have become the standard of care for end stage heart failure as bridge to transplant or destination therapy. Recently, an increase in pump thrombosis among HeartMate II (HM II) LVADs within the first 3 months of implant has been reported. The reason behind the observed increase in thrombosis is unknown but thought to be multifactorial. Increased frequency of transiently elevated power in the early postoperative period has been observed. We sought to determine if these increases in power are associated with future pump thrombosis.
Table 2. Post Transplant Outcomes
Group A (N594) RA ! 15mmHg
p 0.49 0.01 !0.01 0.02 0.74 Figure 1.
067 Reversibility of Restrictive Pulmonary Function Post Cardiac Transplantation Carolyn M. Rosner, Gurusher Panjrath, Ramesh Singh, Shashank S. Desai, Anthony J. Rongione; Inova Health System, Falls Church, VA Background: Pulmonary function testing is an essential component of cardiac transplant evaluation. Severe pulmonary limitations are a contraindication to listing. Dilated cardiomyopathy and pulmonary edema can have a significant impact, causing restrictive but possibly reversible changes in pulmonary function tests (PFT’s). Effect of cardiac transplantation on PFT is not clear. We compared the resting pulmonary function in patients with end-stage cardiomyopathy prior to and shortly after cardiac transplantation. Methods: Seventy-six patients underwent orthotopic heart transplant between January 2009 and June 2013. PFT’s performed prior to cardiac transplant were compared to those obtained 3 months post transplant. Patients who did not have pre and post transplant spirometry, one patient with pulmonary sarcoidosis and one patient who underwent heart-lung transplant were excluded from this analysis. Fifty-one patients were included in this analysis. Results: There was a significant increase in both FEV1 and FVC in a short time after cardiac transplant. There was not a significant change in the FEV1/FVC ratio. Conclusion: In patients without intrinsic lung disease, end-stage cardiomyopathy results in significant, reversible limitations in pulmonary function. Improvements in pulmonary function are seen in the majority of transplant recipients as soon as 3 months post transplant. This important finding should be taken into consideration when evaluating candidates for cardiac transplantation. Table 1. Baseline Characteristics at Time of Transplant Listing
Age (years) Gender (% male, n) Diagnosis (% ICM, n) BMI Previous sternotomy (average number) History of smoking (%, n) Average # of pack years Amiodarone use (current) Pulmonary Bronchodilator use (current) Inhaled Corticosteroid (current) Previous diagnosis of lung disease
54.8 69% 37% 27.2 0.5 47% 8.8 29% 4% 2% 12%
(35) (19)
(24) (15) (2) (1) (6)
dysfunction (46% vs. 19%, p50.036) and higher MELD scores (17 6 5 vs. 13 6 6, p50.028). On average, the first GI bleeding event occurred after 112 6 65 days, and 45% of patients had recurrent GI bleeding episodes (mean 2 6 1 episode per patient). Most patients (9/11) had their first GI bleeding episodes within 4 months post implant. We examined pump management (rpm, flow), average of last 4 INRs and mean arterial pressures (MAP), aortic valve opening and right ventricular (RV) dysfunction (O moderate RV enlargement or TAPSE ! 15 mm on echo) prior to the first GI bleeding and compared to a similar time period (first 4 months post implant) in patients without GI bleeding. There were no differences in speed (9100 6 300 vs. 8900 6 200 rpm for HMII; 2600 6 160 vs. 2600 6 130 rpm for HVAD), flow (5 6 0.5 vs. 4.8 6 0.3 L/min for HM II; 4.6 6 0.3 vs. 5.1 6 0.4 L/ min for HVAD), INR (2 6 0.4 vs. 2.3 6 1), MAP (77 6 9 vs. 78 6 7 mmHg), aspirin use (67% vs. 69%), aortic valve opening (36% vs. 34%) and RV dysfunction (45% vs. 48%) between the two groups. Pre implant liver dysfunction emerged as independent risk factor for subsequent GI bleeding (HR 1.22, 95% CI 1.1 - 1.5). Conclusions: Pre-implant liver dysfunction was associated with subsequent GI bleeding in VAD patients. These findings need to be explored in a larger cohort.
069 Hemodynamic Effects of Intra-Aortic Balloon Counterpulsation in Patients with Advanced Heart Failure Lyanne Buiten, Vikram Paruchuri, Duc Thinh Pham, Michael Kiernan, David DeNofrio, Carey Kimmelstiel, Navin K. Kapur; Tufts Medical Center, Boston, MA Introduction: Intra-aortic balloon counterpulsation pump (IABP) therapy reduces LV afterload by displacing blood volume in the descending aorta during diastole. Recent clinical trials have questioned the utility of IABP therapy in acute myocardial infarction. No studies have examined the clinical utility of IABP therapy in patients with advanced heart failure. The objective of this study is to quantify the hemodynamic effect of IABPs in patients with advanced heart failure. Methods: In this ongoing prospective single-arm study we enrolled 5 patients to date with Stage C/D, NYHA Class III/IV heart failure. After providing informed consent, baseline hemodynamics were acquired with a pulmonary artery catheter and LV conductance catheter. A 50cc IABP was then inserted and activated at full capacity for 15 minutes, then turned off. After a 15 minute period of recovery to baseline, the same 50cc IABP was activated with only 40cc of displacement volume for an additional 15 minutes. After study completion, the IABP was reactivated at full capacity. Results: Mean age of the study population was 53617 years with an LV ejection fraction of 1368%. LV stroke work was significantly reduced with 50cc (12476324 vs 7976239 mmHg mL, 50cc-IABP Off vs On, p!0.04; Figure 1), not with 40cc of volume displacement (13326238 vs 10546187 mmHg mL, 40cc-IABP Off vs On, p5NS). Compared to pre-activation values, no change in arterial elastance, stroke volume, end-systolic or end-diastolic pressures were observed with either device activated. Aortic diastolic pressure was significantly increased with 50cc (7168 vs 104614 mmHg, 50cc-IABP Off vs On, p!0.01) and 40cc (69610 vs 100610 mmHg, 40cc-IABP Off vs On, p!0.01) of volume displacement. No difference between 50cc and 40cc of volume displacement were observed. Conclusion: This is the first use of pressure-volume loop analysis
Table 2. Results
FEV1 FVC FEV1/FVC ratio
Pre transplant
Post transplant
% change
p
2.04 6 0.6 2.82 6 0.8 0.73 6 0.1
2.32 6 0.6 3.08 6 0.8 0.78 6 0.2
+13% +9% +7%
!0.01 !0.01 0.07
068 The Relation Between Liver Dysfunction and Gastrointestinal Bleeding in Patients with Ventricular Assist Devices David Lowe, Georg Wieselthaler, Liviu Klein; UCSF, San Francisco, CA Purpose: Gastrointestinal (GI) bleeding is a major comorbidity in patients with ventricular assist devices (VAD). It is unknown if pre-implant liver dysfunction is implicated in this pathophysiology. Methods: In 69 bridge-to-transplant (BTT) and destination therapy (DT) patients with HeartWare (HVAD) and HeartMate II VAD (HMII) we analyzed the relation between pre-implant liver dysfunction (cirrhotic appearance or portal hypertension on ultrasound, or MELD score O 20) and subsequent GI bleeding. Results: There were 11 patients (16%) with GI bleeding. These patients were older (62 6 7 vs. 56 6 16 yrs, p50.033) and more likely to have ischemic etiology (82% vs. 45%, p50.024) than patients without GI bleeding. There was no difference in women (18% vs. 14%), INTERMACS profile (2.1 6 1 vs. 2.4 6 1), NYHA class (3.5 6 0.4 vs. 3.4 6 0.5), ejection fraction (0.21 6 0.09 vs. 0.24 6 0.07), or days on device (363 6 283 vs. 275 6 268 days) between groups. Patients with GI bleeding had higher incidence of pre-implant liver
Figure 1.
The 19th Annual Scientific Meeting to study the effects of IABP therapy in patients with advanced heart failure. Initial observations suggest that larger capacity IABP activation reduces LV stroke work in patients with advanced heart failure. The study is actively enrolling through 2015.
070 Elevated Right Atrial Pressure Predicts Post Heart Transplant Outcomes Carolyn M. Rosner, Anthony J. Rongione, Gurusher Panjrath, Palak Shah, Shashank S. Desai, Ramesh Singh; Inova Health System, Falls Church, VA Background: Orthotopic heart transplantation (OHT) is the definitive treatment for end stage heart failure. Patient selection is key in improving post OHT outcomes. Pre-operative right ventricular dysfunction is associated with worse outcomes after mechanical circulatory support but its effect on post OHT outcomes has not been well described. Right atrial (RA) pressure is commonly used as a surrogate for RV function. We compared post OHT outcomes in patients with and without preoperative elevated RA pressure. Methods: An analysis of 124 patients who underwent isolated OHT at our institution from January 2008-October 2014 was performed. Patients undergoing re-transplantation were excluded. One hundred seventeen patients were included in this analysis. Groups were divided based on preoperative RA pressure. Baseline characteristics and post OHT outcomes (post OHT length of stay; 30 day, 1 year and 3 year survival and clinically significant rejection in the 1st year) were compared. Results: Pre OHT characteristics were similar between the 2 groups except for a difference in age and PVR, as shown in Table 1. Post heart transplant survival was worse in the group with pre transplant RA pressure O15mmHg, as shown in Table 2. Conclusion: Pre-operative elevated RA pressure was associated with a worse short and intermediate term (1 and 3 year) survival after OHT. There was no difference in post transplant rejection in the first year. Possible factors for poor survival include underestimation of pulmonary hypertension or organ dysfunction. RA pressures are readily available and may allow for a more accurate prediction of post OHT outcomes.
Table 1. Baseline Characteristics at Time of Transplant
Age Gender (% male) Diagnosis (%ICM) BMI Previous sternotomy Mechanical circulatory support LVAD/BiVAD/TAH ECMO IABP None UNOS status 1A at time of transplant Wait time to transplant (days) RA RVSWI (PAM-CVP) PVR TPG CO
Group A (N594) RA ! 15mmHg
Group B (N523) RA $ 15mmHg
55 73% 38% 27.3 82% 72%
48 70% 30% 28.3 78% 61%
62/4/1 1 0 26 77%
11/2/0 1 0 9 91%
255.4 6 235.2 7.1 6 3.9 13.3 6 6.8
209.3 6 219.2 18.0 6 3.3 13.6 6 8.1
0.40
1.9 6 1.2 8.5 6 4.6 4.7 6 1.2
2.5 6 1.5 9.5 6 3.8 5.1 6 3.8
0.03 0.35 0.60
p 0.02 0.71 0.50 0.37 0.69 0.28
Post transplant LOS (days) 30 day survival 1 year survival 3 year survival Incidence of rejection in the 1st year
18.6 98% 92% 86% 36%
Group B (N523) RA $ 15 17.7 83% 67% 50% 32%
HFSA
S39
071 VNS Does Not Reduce Heart Failure Progression in a Canine High Rate Pacing Model of HF Avram Scheiner; Medtronic, Mounds Veiw, MN Background: There is a significant unmet clinical need for effective therapies for heart failure (HF) patients. One potential therapeutic approach is Vagal Nerve Stimulation (VNS) in which a lead is placed on the cervical portion of the vagus nerve and stimulated using high frequency pulses. Multiple preclinical laboratories have published positive studies using this technique for HF treatment. This study attempts to duplicate one of these studies.1 Method: Sixteen dogs were implanted with a bipolar cuff lead (Inspire Medical Systems, Model 4063) placed on the cervical vagus nerve and connected to a nerve stimulator. A pacemaker was implanted with leads in the RA and in the RV for high rate Pacing (HRP). At post-operative week 2, each animal was randomized into either the control or VNS test group. HRP was started at week 2 in all animals to induce HF. VNS therapy was initiated at week 2 in the test group. For the VNS test group, VNS therapy was cycled continuously at 14 seconds on-12 seconds off. VNS therapy settings were at a frequency of 19 hertz and pulse width of 450 mseconds. Therapy was adjusted just below the level of coughing threshold for chronic VNS delivery. For each animal a series of weekly awake monitors were performed to ensure system integrity and therapy delivery. Echo measurements, ECG and blood samples were taken 2 weeks post-op at the initiation of high rate pacing, and again at weeks 6 and 10. The echo technician was blinded to each animal’s randomization assignment. The primary parameters of interest of the study were echo measures of remodeling and cardiac function. Secondary measures included various plasma biomarkers and post mortem heart size and weight and histological measurements. Results: The results of this study indicate that VNS does not produce a therapeutic effect in this high rate pacing HF canine model. The VNS treatment arm showed no significant difference compared to the control group in the primary endpoints in this study from randomization to 6 weeks or 10 weeks (EF, p5 0.60 and 0.83, EDV, p5 0.75 and 0.53 or ESV p5 0.90 and 0.63). A comparison of the primary endpoints of the control groups in this study and the previous published study1 suggests that similar changes were produced by the HRP model in both studies. Secondary measures of plasma biomarkers also showed no statistical differences between control and treatment arms at 6 and 10 weeks. Pathological findings showed no statistical difference in heart dimensions and weight. Conclusions: Although the canine HF model and VNS therapy technique were duplicated as done in the published positive VNS study, different results are seen. The results of this study indicate that VNS does not produce a therapeutic effect in this high rate pacing HF canine model. 1 Youhua Zhang, et al., “Chronic Vagus Nerve Stimulation Improves Autonomic Control and Attenuates Systemic Inflammation and Heart Failure Progression in a Canine High Rate Pacing Model” Circ Heart Fail published online Sep 22, 2009; DOI: 10.1161/CIRCHEARTFAILURE.109.873968
072 Early Elevated Pump Power and Associated Hemolysis Amongst HeartMate II Left Ventricular Assist Devices Anjan Tibrewala, Michael Nassif, David Raymer, Justin Vader, Shane LaRue, Scott Silvestry, Greg Ewald; Washington University, St. Louis, MO
0.12
!0.0001 0.88
Background: Continuous-flow left ventricular assist devices (CF-LVAD) have become the standard of care for end stage heart failure as bridge to transplant or destination therapy. Recently, an increase in pump thrombosis among HeartMate II (HM II) LVADs within the first 3 months of implant has been reported. The reason behind the observed increase in thrombosis is unknown but thought to be multifactorial. Increased frequency of transiently elevated power in the early postoperative period has been observed. We sought to determine if these increases in power are associated with future pump thrombosis.
Table 2. Post Transplant Outcomes
Group A (N594) RA ! 15mmHg
p 0.49 0.01 !0.01 0.02 0.74 Figure 1.