Date of Award
7-2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Biomedical Engineering and Sciences
First Advisor
Venkat Keshav Chivukula, Ph.D.
Second Advisor
Peshala Thibbotuwawa Gamage, Ph.D.
Third Advisor
Ryan T. White, Ph.D.
Fourth Advisor
Linxia Gu, Ph.D.
Abstract
LVAD speed optimization is essential for efficient LVAD therapy and to minimize complications. However, the ideal LVAD speed is unknown and must be tailored for each patient. The interplay between the LVAD, systemic, and pulmonary circulations is critical and should be considered during optimization. A computational hemodynamic model that can be tailored for each patient may provide clinicians with useful guidance and reduce the need for repeated invasive studies. This study sought to customize and evaluate a patient-specific LVAD hemodynamic optimization model.
We conducted a retrospective analysis on 25 patients implanted with HM3 and who underwent right heart catheterization (RHC) outpatient titration. A custom designed computational hemodynamic lumped parameter model (HLPM) was developed consisting of 27 equation differential algebraic expression modeling with more than 50 customizable physiological parameters. The HM3 pressure-flow curves were incorporated and the HLPM was customized for each patient based on their systemic and pulmonary resistance parameters. Each patient-specific model was evaluated independently for optimizing LVAD speed based on several mean arterial pressure (MAP) targets ranging from 70-90 mmHg. The optimized HLPM model was compared to RHC data and clinician guided speed optimization. The HLPM was further developed to model the right side of the heart by incorporating patient-specific pulmonary vascular resistance, capacitance, and elastance.
16 patients met analysis criteria, with a median age of 63 years, 69% male and 75% white. 69% were implanted as destination therapy, with a median baseline speed of 5100 rpm. 16 customized patient-specific models were successfully obtained. To achieve a target MAP of 70 mmHg, the HLPM predicted LVAD speed reduction for 14 patients (87.5%), with a median speed reduction of 275 rpm. For a target MAP of 80 mmHg, HLPM predicted speed reduction for 10 patients (62.5%) and a median speed reduction of 230 rpm. For the highest target MAP of 90 mmHg, the HLPM predicted a speed reduction for 6 patients (37.5%), with a median speed reduction of 115 rpm. Compared to the clinical guided speed optimization, the HLPM suggested a speed reduction in 10 patients (62.5%), with a median reduction of 160 rpm and a median speed increase of 175 rpm for the remaining 6 patients. Finally, the HLPM indicated that speed optimization would shift the pulmonary artery pressure ranges toward the healthy range (i.e.30 mmHg) for 14 patients (87.5%).
Overall, there was congruence between HLPM predictions and RHC and clinician guided speed optimization, with a median difference of 40 rpm. However, the magnitude of speed change varied. The patient-specific HLPM provides a valuable option for clinicians to evaluate LVAD speed titration changes, including analysis of pulmonary system parameters to avoid right heart overload. Future studies will include further customization of model parameters and prospective comparison for improved LVAD speed optimization predictions.
Recommended Citation
Grant, Holly Felice, "Patient-Specific Hemodynamic Modeling for Optimizing Left Ventricular Assist Device and Right Heart Health" (2024). Theses and Dissertations. 1458.
https://repository.fit.edu/etd/1458
Comments
Copyright is held by author.