# Effect of RVAD Cannulation Length on Right Ventricular Thrombosis Risk: An In Silico Investigation

## TL;DR

This study uses computer models to show that longer RVAD cannulation reduces the risk of blood clots in the right ventricle.

## Contribution

The study introduces a patient-specific in silico model to evaluate how RVAD cannulation length affects thrombosis risk.

## Key findings

- A 25-mm cannulation length reduced thrombosis risk due to improved flow energy and reduced stagnation.
- Longer cannulation increased washout rate and decreased blood residence time.
- Shorter cannulation lengths (5-15 mm) were associated with higher thrombosis risk.

## Abstract

Left ventricular assist devices (LVADs) have been used off-label as long-term support of the right heart due to the lack of a clinically approved durable right VAD (RVAD). Whilst various techniques to reduce RVAD inflow cannula protrusion have been described, the implication of the protrusion length on right heart blood flow and subsequent risk of thrombosis remains poorly understood. This study investigates the influence of RVAD diaphragmatic cannulation length on right ventricular thrombosis risk using a patient-specific right ventricle in silico model validated with particle image velocimetry. Four cannulation lengths (5, 10, 15 and 25 mm) were evaluated in a one-way fluid–structure interaction simulation with boundary conditions generated from a lumped parameter model, simulating a biventricular supported condition. Simulation results demonstrated that the 25-mm cannulation length exhibited a lower thrombosis risk compared to 5-, 10- and 15-mm cannulation lengths due to improved flow energy distribution (25.2%, 24.4% and 17.8% increased), reduced stagnation volume (72%, 68% and 49% reduction), better washout rate (13.0%, 11.6% and 9.1% faster) and lower blood residence time (6% reduction). In the simulated scenario, our findings suggest that a longer RVAD diaphragmatic cannulation length may be beneficial in lowering thrombosis risk; however, further clinical studies are warranted.

The online version contains supplementary material available at 10.1007/s10439-024-03474-4.