The Effect of Inflow Cannula Length on the Intraventricular Flow Field of the EvaHeart LVAD-Assisted Heart

Abstract

Abstracts S319position 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. ( 880) WITHDRAWN ( 881)Purpose: Advanced heart failure (HF) is a characterized by poor functional capacity, fluid retention, elevated filling pressures and increased arrhythmia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.

Reducing regional flow stasis and improving intraventricular hemodynamics with a tipless inflow cannula design: An in vitro flow visualization study using the EVAHEART LVAD

“…In addition, a decrease in both average and systolic velocities were observed within the inflow cannula . An increase in the insertion length of the inflow cannula into the LV was also associated with increased flow stasis and reduced pulsatility …”

The Influence of Rotary Blood Pump Speed Modulation on the Risk of Intraventricular Thrombosis

“…The major cause of death for continuous flow LVAD patients are neurological events . Many factors can be attributed to this adverse event: one potential reason could be intraventricular thrombosis, stemming from unfavorable flow patterns caused by, but not limited to, the LVAD inflow cannula design, length, and position .…”