Introduction:
The effective treatment for patients with heart failure with preserved ejection fraction is not yet established. We previously reported the concept of the left atrial assist device (LAAD) that pumps blood from the left atrium to the left ventricle to treat diastolic heart failure (DHF). We have now developed the first working prototype of the LAAD that can be implanted at the mitral valve level (Fig. 1). The purpose of the study was to demonstrate that the LAAD can reduce left atrial pressure (LAP) and increase cardiac output (CO) while maintaining arterial pulsatility and normal aortic valve function in the
in vitro
DHF model.
Methods:
The LAAD was tested at three pump speeds (3,600, 4,400 and 5,200 rpm) on a pulsatile mock loop with a pneumatic pump that simulated the normal function of the native ventricle, as well as mild, moderate, and severe DHF conditions, by adjusting the diastolic drive pressure to limit diastolic filling of the ventricle.
Results:
Without the LAAD, CO and aortic pressure (AoP) decreased dramatically: from 3.9 L/min and 102 mm Hg at normal heart condition to 1.0 L/min and 33 mm Hg at severe DHF, respectively (Fig. 2A, 2B). With LAAD support, both CO and AoP recovered to normal heart values at 4,200 rpm and surpassed normal heart values at 5,200 rpm (Fig. 2A, 2B). With LAAD support, LAP recovered to that of the normal heart condition at 5,200 rpm (Fig. 2C). The pulsatility was maintained (Fig. 2D), as all the CO went through the aortic valve.
Conclusions:
These initial
in vitro
results support our hypothesis that use of the LAAD increases CO and AoP and decreases LAP under DHF conditions, while maintaining arterial pulsatility and full function of the aortic valve.
March 2020 at a glance: heart failure with preserved ejection fraction, left atrial myopathy, atrial fibrillation and cardiac amyloidosis
