Control of ventricular unloading using an electrocardiogram-synchronized Thoratec paracorporeal ventricular assist device

Amacher, Raffael; Weber, Alberto; Brinks, Henriette; Axiak, Shannon; Ferreira, Antonio; Guzzella, Lino; Carrel, Thierry; Antaki, James; Vandenberghe, Stijn (2013). Control of ventricular unloading using an electrocardiogram-synchronized Thoratec paracorporeal ventricular assist device. Journal of thoracic and cardiovascular surgery, 146(3), pp. 710-717. St. Louis, Mo.: Mosby 10.1016/j.jtcvs.2012.12.048

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OBJECTIVE: Current pulsatile ventricular assist devices operate asynchronous with the left ventricle in fixed-rate or fill-to-empty modes because electrocardiogram-triggered modes have been abandoned. We hypothesize that varying the ejection delay in the synchronized mode yields more precise control of hemodynamics and left ventricular loading. This allows for a refined management that may be clinically beneficial. METHODS: Eight sheep received a Thoratec paracorporeal ventricular assist device (Thoratec Corp, Pleasanton, Calif) via ventriculo-aortic cannulation. Left ventricular pressure and volume, aortic pressure, pulmonary flow, pump chamber pressure, and pump inflow and outflow were recorded. The pump was driven by a clinical pneumatic drive unit (Medos Medizintechnik AG, Stolberg, Germany) synchronously with the native R-wave. The start of pump ejection was delayed between 0% and 100% of the cardiac period in 10% increments. For each of these delays, hemodynamic variables were compared with baseline data using paired t tests. RESULTS: The location of the minimum of stroke work was observed at a delay of 10% (soon after aortic valve opening), resulting in a median of 43% reduction in stroke work compared with baseline. Maximum stroke work occurred at a median delay of 70% with a median stroke work increase of 11% above baseline. Left ventricular volume unloading expressed by end-diastolic volume was most pronounced for copulsation (delay 0%). CONCLUSIONS: The timing of pump ejection in synchronized mode yields control over left ventricular energetics and can be a method to achieve gradual reloading of a recoverable left ventricle. The traditionally suggested counterpulsation is not optimal in ventriculo-aortic cannulation when maximum unloading is desired.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Department of Cardiovascular Disorders (DHGE) > Clinic of Heart Surgery 05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > DKV - Anaesthesiology 10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Cardiovascular Engineering (CVE)
UniBE Contributor:	Weber, Alberto, Most, Henriette, Axiak, Shannon, Carrel, Thierry, Vandenberghe, Stijn
Subjects:	600 Technology > 610 Medicine & health
ISSN:	0022-5223
Publisher:	Mosby
Language:	English
Submitter:	Factscience Import
Date Deposited:	04 Oct 2013 14:39
Last Modified:	27 Feb 2024 14:29
Publisher DOI:	10.1016/j.jtcvs.2012.12.048
PubMed ID:	23317942
Web of Science ID:	000323605800039
Uncontrolled Keywords:	Animals, Aorta, Arterial Pressure, Disease Models, Animal, Electrocardiography, Heart Rate, Heart-Assist Devices, Prosthesis Design, Pulmonary Circulation, Pulsatile Flow, Regional Blood Flow, Sheep, Stroke Volume, Time Factors, Ventricular Dysfunction, Left, Ventricular Function, Left, Ventricular Pressure
URI:	https://boris.unibe.ch/id/eprint/15717 (FactScience: 223146)