Integration of Compliance Chambers into Diaphragm Displacement Pump to Double the Pumping Flow of Pediatric Paracorporeal Pulsatile Ventricular Assist Device

The paracorporeal Berlin Heart EXCOR is the only FDA-approved ventricular assist device (VAD) for pediatric patients. This pulsatile diaphragm displacement pump (DDP) is small/light weight to facilitate pediatric patient ambulation. However, EXCOR efficiency is only 50% since it withdraws and pumps blood at different times (interrupted pulsatile flow). This generates a high peak blood flow rate, which may cause blood damage. A paracorporeal continuous flow PediMag VAD has also been used in smaller children. This centrifugal pump is highly efficient due to the constant flow through the drainage/infusion cannulas, but the PediMag pump head must be attached to a bulky/heavy motor, which hinders ambulation. We previously developed a transapical to aorta (TAA) double lumen cannula (DLC) for a minimally invasive ambulatory LVAD, which showed excellent 96 hr performance/hemocompatibility in neonate lambs. Our ultimate goal is to develop an efficient, minimally invasive, paracorporeal LVAD system for pediatric patients, which combines the small size/weight (ambulation potential) of current interrupted pulsatile flow pump (e.g EXCOR) and the current high efficiency of a continuous flow pump (e.g PediMag). The enabling technology is a compliant diaphragm displacement pump (cDDP), which has compliance chambers integrated into the drainage and infusion outlets to double blood flow. The cDDP will be high performing due to: 1) noninterrupted/continuous blood flow; 2) infusion/drainage compliance chambers that decrease cDDP afterload/increase cDDP preload. The lower peak drainage/infusion flow of the cDDP will also reduce blood trauma. Preliminary data showed that adding compliance chambers increased pumping flow from 1.1 to 2.6 L/min and decreased peak flow rate. The Phase I SBIR objective is to design and fabricate a cDDP working prototype with optimal compliance chambers size. This cDDP will be tested in lambs with our previously developed TAA DLC. Specific Aim 1: To design, fabricate, and bench test a cDDP. Compliance chambers will be integrated into the cDDP drainage and infusion outlets. The cDDP will be made of polycarbonate housing with a polyurethane diaphragm in the middle. A tricuspid valve will connect the cDDP housing to the two small silicone compliance chambers. The final prototype will be tested for 1 week in a 37% glycerin mock loop for performance/reliability/durability. Specific Aim 2: To test the cDDP working prototype in lambs. The cDDP will be combined with the TAA DLC to form a less invasive, ambulatory LVAD, which will be tested in 10-15 kg lambs (n=9) to evaluate 6 hr performance/reliability and initial biocompatibility. Prototype design/fabrication/bench testing will be done at W-Z Biotech, and the lamb studies will be done at the University of Kentucky. Rather than fine-tuning existing technology, our cDDP is a novel invention, which will enable a pulsatile paracorporeal VAD with doubled efficiency. This technology can also be used in adults and may significantly impact cardiogenic shock/bridge to heart transplant management.