Heart failure (HF) is a leading cause of death worldwide, with a growing prevalence. Left ventricular assist devices (LVADs) are used in patients with severe HF to reduce the heart’s workload and enhance cardiac output. However, complications such as right ventricular failure and thrombosis pose significant risks. Furthermore, the interplay between the device and the compromised cardiovascular system creates unique challenges in studying these patients. Computational modeling offers a powerful, non-invasive approach to studying LVAD patients, enabling detailed simulations of cardiovascular hemodynamics. This work presents a patient-specific computational modeling pipeline that integrates 3D hemodynamic simulations of the LV, left atrium, aortic root, and LVAD with a closed-loop 0D lumped parameter model of the full cardiovascular system. By optimizing model parameters using patient data, this framework captures the complex flow and systemic interactions induced by LVADs. The model demonstrates strong agreement with patient data, with key hemodynamic metrics aligning well with clinical observations. Additionally, it enables detailed analysis of regurgitant flows, ventricular pressure-volume dynamics, and systemic circulation changes, offering a valuable tool for understanding patient-specific responses to LVAD therapy and guiding treatment optimization.