Left Ventricular Assist Device Inflow Cannula Insertion Depth Influences Thrombosis Risk

Area of Science:

• Cardiovascular Engineering
• Biomedical Fluid Dynamics
• Medical Device Thrombogenicity

Background:

• Left ventricular assist device (LVAD) use is increasing, yet complications like stroke and device thrombosis persist.
• Patient-specific factors and device implantation details significantly influence LVAD outcomes.
• The precise impact of inflow cannula insertion depth on intraventricular hemodynamics and thrombogenicity remains incompletely understood.

Purpose of the Study:

• To investigate the influence of left ventricular assist device (LVAD) inflow cannula insertion depth on intraventricular hemodynamics and platelet activation.
• To quantify the relationship between cannula depth, platelet shear stress history, and residence time.
• To determine if optimizing inflow cannula depth can mitigate thrombogenicity and reduce stroke risk in LVAD patients.

Main Methods:

• Utilized patient-derived computational models of the left ventricle (LV), mitral valve (MV), and LVAD inflow cannula.
• Employed unsteady computational fluid dynamics (CFD) to simulate blood flow patterns.
• Tracked individual platelets (Lagrangian approach) to quantify thrombogenicity using metrics like shear stress history (SH) and residence time (RT) for two insertion depths (12 mm reduced, 27 mm conventional).

Main Results:

• Deeper inflow cannula insertion (27 mm) led to significantly higher platelet shear stress histories (SH) and longer residence times (RT), especially in patients with smaller LV dimensions.
• Abnormal intraventricular hemodynamics were observed with deeper insertion, correlating with increased platelet activation.
• Reduced inflow cannula depth (12 mm) promoted better LV washout and decreased platelet SH, suggesting improved hemocompatibility.

Conclusions:

• LVAD inflow cannula insertion depth is a critical factor influencing intraventricular hemodynamics and thrombogenicity.
• Increased SH and RT associated with deeper insertion highlight an elevated risk of platelet activation and potential stroke.
• Optimizing inflow cannula depth during surgical planning may represent a key strategy to improve LVAD therapy outcomes and patient safety.