Abstract 9547: Tissue Doppler and Strain Imaging Can Facilitate Weaning Decisions in Patients with Evidence of Cardiac Recovery Suring Mechanical Ventricular Support
Background: Echocardiographic monitoring of cardiac size and function during “off-pump” trials is the cornerstone for detection of cardiac recovery during mechanical unloading. Parameters such as left ventricular (LV) diameters and LVEF are helpful to predict the outcome after possible LV assist device (LVAD) removal. However, high inter-observer variability and load dependency of EF measurements are important limitations. Because velocity parameters measurable by tissue Doppler and strain imaging are more reliable for estimation of LV function, we assessed their usefulness for evaluation of recovery.
Methods: Pulsed-wave tissue Doppler (PW-TD) measurements of systolic wall motion peak velocities (Sm) at the basal posterior wall were performed since 1999 during all “off-pump” trials before LVAD removal and at all follow-up controls of post-weaning cardiac function. Since 2005, 2D strain and strain rate (SR) measurements (radial, circumferential and longitudinal) were also performed before and after LVAD removal. The prospectively collected PW-TD and 2D strain data were evaluated for their usefulness to predict weaning successes.
Results: Heart failure (HF) recurrence after LVAD removal occurred in 10 (31.3%) of 32 patients who underwent PW-TD. Longitudinal and radial Sm was lower in these 10 patients than in those with post-weaning cardiac stability (p < 0.01) Stable patients showed Sm > 8 cm/s. Off-pump Sm ≥ 8cm/s showed predictive values between 87 and 90% for 5 year post-weaning stability. Strain and SR measured in 23 patients revealed higher systolic values in patients with post-weaning stability (p < 0.01). In stable patients global systolic strain and SR values were: ≥ 30% and ≥ 0.9/s for radial thickening, ≥ 15% and ≥ 0.8/s for circumferential shortening, ≥ 12% and ≥ 0.65/s for longitudinal shortening, respectively. Sm, strain and SR instability before and early after LVAD removal appeared predictive for post-weaning recurrence of HF.
Conclusion: PW-TD and 2D-strain imaging allow distinction between patients with and without the potential to maintain cardiac stability after LVAD removal and can therefore be useful for evaluation of unloading-induced cardiac recovery and also for prognostic assessments before and early after LVAD removal.
- © 2011 by American Heart Association, Inc.