S25 - Custom cannula engineering heart-lung perfusion and transplantation applications

Saturday, October 11, 2025

10:00 AM - 11:00 AM PDT

Location: Exhibit Hall F, G & H

Presenting Author(s)

Colleen Burke

Undergraduate Student Researcher
Vanderbilt University
Chicago, Illinois, United States

Co-Author(s)

YW

Yerin Woo

Postdoctoral Researcher
Vanderbilt University Medical Center, United States
SB

Sriya Bapatla

PhD Student
Vanderbilt University, United States
AM

Abigail Martel

Undergraduate Student Researcher
Vanderbilt University, United States
Lawrence W. Li

Undergraduate Researcher
Vanderbilt University
Clarksburg, Maryland, United States
GG

Gabriella Glomp

Research Assistant
Vanderbilt University Medical Center, United States
AK

Andrew R. Kumpfbeck

Post Doctoral Research Fellow
Vanderbilt University Medical Center, United States
CD

Caitlin Demarest

Assistant Professor, Department of Thoracic Surgery
Vanderbilt University Medical Center, United States

Last Author(s)

Rei Ukita, PhD

Research Assistant Professor, Cardiac Surgery
Vanderbilt University Medical Center
Nashville, Tennessee, United States

Primary Investigator(s)

Rei Ukita, PhD

Research Assistant Professor, Cardiac Surgery
Vanderbilt University Medical Center
Nashville, Tennessee, United States

Introduction: : Cannulas serve a critical role in clinical applications such as mechanical circulatory support, organ transplantation, and ex vivo organ perfusion by serving as essential conduits between organ systems and perfusion circuits. As novel organ support platforms are developed, the design and optimization of specialized cannulas and cannulation strategies are essential to ensure adequate blood flow to donor organs.

One example is the development of an enhanced heart-lung perfusion model designed to study interventions that optimize cardiac function. This model will build on the traditional Langendorff setup by incorporating bidirectional flow and filling of the right side of the heart to evaluate it in both its “working” and “resting” modes. In this model, an aortic cannula serves as the critical interface between the donor heart and the perfusion circuit.

While commercial aortic cannulas are available, several challenges exist. Existing cannulas are too long, requiring a great volume of blood needed to fill them. This increased blood volume may put excessive pressure on the heart and can inhibit its ability to beat independently. The extended length may also increase the risk of introducing air bubbles into the heart, potentially leading to complications like air embolism. Moreover, the cannula position may shift over time with heart movement, which can further limit blood flow.

To address these surgical limitations, we designed a custom aortic cannula prototype featuring a reduced length and cosmetic additions to maximize perfusion and minimize air entrainment & cannula displacement, offering a more effective alternative for heart-lung perfusion applications.

Materials and

Methods: : A test cannula was designed in Fusion 360, modeled around the LivaNova 36 Fr. Single Stage Lighthouse Tip Cannula, which served as the comparator for all testing purposes. While the tip holes mimicked the comparator to maintain similar pressure-flow characteristics, several modifications were made: the cannula was shortened, surgical ligature holders were added, and a built-in connector was included to interface with standard 3/8” tubing.

The design was sliced and prepared for printing using Formlabs Flexible 80A resin, selected for its combination of flexibility and durability - both essential for the intended application. After printing, the cannula was washed in isopropyl alcohol for 15 minutes in a Formlabs Form Wash. It was cured for 9 minutes at 60°C in a Formlabs Form Cure, supports were removed, and it was post-cured for an additional 4 minutes.

Pressure-flow characteristics of the test and comparator cannulas were evaluated using a benchtop saline circuit consisting of 3/8” and ½” tubing, a reservoir bag, an Affinity CP Centrifugal Blood Pump, and the cannula. Circuit flow rates were increased in 0.5 L/min increments from 0 to 8 L/min while observing pressure drop across the cannulas.

Assessment of hemolysis in the test and comparator cannulas was completed in a blood circuit with a RotaFlow Centrifugal pump. One liter of heparinized bovine blood was introduced into each circuit. Both circuits operated at a flow rate of 3 L/min. Baseline and hourly blood samples were collected and analyzed for plasma free hemoglobin (PFH) concentration.

Results, Conclusions, and Discussions:: The test cannula has a total length of 180 mm (Fig. 1), including the integrated tubing connection, compared to 380 mm for the comparator cannula, excluding the external tubing connection. Both cannulas have an external diameter of 36 Fr (12 mm). The test cannula also features multiple rungs for surgical ligatures about 7 mm from the tip.

Pressure-flow profiles were comparable between test and comparator cannulas. At low flow rates ( < 3 L/min), the test cannula exhibited a slightly lower pressure drop than the comparator cannula. This is particularly significant given that flow rates for the cannula’s intended application are expected to remain predominantly within the range of 1-3 L/min. At higher flow rates (3-8 L/min), the test cannula exhibited a slightly greater pressure drop. Pressure-flow data was fitted with a second-order polynomial relationship, consistent with the behavior predicted by minor losses in pipe flow.

Hemolysis testing (Fig. 3) indicated similar hemolytic profiles. The difference in plasma free hemoglobin (PFH) concentration between test and comparator was within 10 mg/dL cannulas at all time points.

The test cannula was successfully implemented in a four-hour benchtop heart-lung perfusion study of a porcine heart and lung (Fig. 1), achieving both reinfusion and drainage flow during “resting” and “working” modes of the model.

Overall, the test cannula demonstrated pressure-flow and hemolysis profiles comparable to those of the commercially available comparator, supporting its viability as an alternative. Use of the test cannula in a benchtop heart-lung perfusion study further validated its efficacy and confirmed its surgical practicality, reinforcing its validity. These findings emphasize the value of further developing custom cannulas tailored for organ perfusion and transplantation research, where rapid prototyping and iterative design can drive advancements in cannulation techniques and accelerate the study of organ systems and transplant platforms.

Acknowledgements and/or References (Optional): : This project was funded by the TSF Nina Starr Braunwald Research Award and Vanderbilt Undergraduate Summer Research Program (VUSRP). 3D printing resources were provided by Vanderbilt Institute for Surgery and Engineering (VISE) and the Wond’ry. Additional resources were provided by the Light Surgical Research and Training Laboratory.