Novel Adjustable Coupler For Coaxial Cannulation Via Transapical Access For Ambulatory Extracorporeal Membrane Oxygenation
Hossein Amirjamshidi1, Jude S. Sauer2, Christopher J. Hand2, Jeremy Schiele2, Sunil Prasad1
1University of Rochester Medical Center, Rochester, NY, USA, 2LSI SOLUTIONS, Victor, NY, USA
BACKGROUND: ECMO patients could benefit from low pressure, high flow single site cannulation facilitating ambulation while avoiding groin and vascular wounds. Minimally invasive access for coaxial cannulation of the heart’s apex can potentially enable optimized blood flow with reduced morbidity and mortality. METHODS: An ex-vivo porcine beating heart model was developed (figure 1) to assess for leakage of transapical cannulation sites secured using automated suturing. 10 thawed porcine hearts cannulated with 25Fr cannulae and secured with purse-string sutures placed using automated remote suturing technology were evaluated with simulated ECMO saline pressures and flows; after decannulation and purse-string closure, hermetic security was assessed by pressurizing the left ventricle. 5 additional porcine hearts were cannulated and acutely assessed for bursting pressure with the cannula present and following decannulation with wound closure. Next, a novel adjustable coupler was developed to enable single site cannulation employing coaxial commercially available cannulas. This coupler enabled independent adjustment of the inner perfusate cannula fenestrations above the Sino-Tubular Junction with the outer return cannula inside of the left ventricle for unloading. ECMO circuit testing was conducted under clinical settings to obtain pressure and flow measurements of a variety of coaxial cannulae configurations and controls. RESULTS: 10 cannulated porcine hearts remained hermetic for 24hrs of testing and apical wound closure with a 276mmHg mean intraventricular pressure. 5 hearts in the acute bursting study remained hermetic with the cannula (mean, 370mmHg) and at apical wound closure (mean, 279mmHg). Of the 9 coaxial coupler combinations tested using ECMO circuits, the 19Fr inner coupled to the 34Fr outer cannula provided preferred pressures (e.g., 4,500rpm: 220mmHg at 4.7L; 5,000rpm: 274mmHg at 5.29L). CONCLUSIONS: This ex-vivo porcine pressurized beating heart model demonstrated excellent seals of transapical cannulation sites and wound closure using automated suturing. Single site transapical access using coaxially coupled cannulae may offer patients ambulation plus low pressure, high flow, ECMO therapy. These initial results encourage further exploration to enable critically ill ECMO patients the benefits of important physical and emotionally stimulating activities, while avoiding potentially catastrophic groin and vascular complications.
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