Pediatric Transapical Double Lumen Cannula with Integrated Compliance Chambers Doubles Flow of Paracorporeal Pulsatile VAD

Pediatric patients with severe heart failure require a ventricular assist device (VAD). The paracorporeal Berlin Heart EXCOR is still the only FDA-approved VAD for pediatric patients. This diaphragm displacement pump is small/light weight to facilitate ambulation. However, EXCOR withdraws and pumps blood at different times for interrupted pulsatile blood flow, with its drainage and infusion cannulas functioning only half the time (50% efficiency). EXCOR also generates a high peak blood flow rate, which may cause blood damage. A paracorporeal continuous flow (PediMag/CentriMag) VAD has also been used with Berlin Heart cannulas in smaller children, but its bulky/heavy motor hinders ambulation. Pediatric paracorporeal VADs require two separate cannulas for withdrawal and infusion and their installation requires an invasive median sternotomy, which complicates later surgery for heart transplant or repair. Our ultimate goal is to develop a minimally invasive, high efficiency paracorporeal pulsatile diaphragm displacement VAD system for pediatric patents. The enabling technology is a transapical double lumen cannula (DLC) with integrated compliance chambers that features: 1) Single transapical cannulation via less invasive, small left thoracotomy; 2) Two integrated compliance chambers that: a) Continuously withdraw/infuse blood to increase efficiency for higher blood flow rates; b) Adjust continuous flow fluctuation for desired pulsatility; c) Reduce peak blood flow rate to mitigate blood trauma; d) Reduce infusion lumen peak pressure, decreasing pump afterload to enhance pump output; e) Allow smooth withdrawal to infusion transition for high frequency pumping. Bench testing of an initial transapical DLC with integrated compliance chambers prototype with EXCOR showed double pumping flow with decreased peak pump flow. The Phase I SBIR objective: We will redesign a transapical DLC with optimal minimal compliance chambers and conduct performance testing in lambs. Specific Aim 1: To design, fabricate, and bench test the high efficiency, transapical DLC with integrated compliance chambers. The transapical DLC compliance chambers will be integrated into the drainage and infusion outlets. The 24 Fr main DLC body will be one-piece reinforced polyurethane. The super-elastic silicone compliance chambers will be very small with 50% stroke volume. The final prototype will be tested for 1 week in an EXCOR mock loop with 37% glycerin for performance/reliability/durability. Specific Aim 2: To test the new 24 Fr transapical DLC with compliance chambers in an EXCOR VAD circuit in lambs (n=8). These lamb (10-15 kg) studies will investigate ease of transapical deployment, 6 hr in vivo performance/reliability, and initial biocompatibility. Prototype design/fabrication/bench testing will be done at W-Z Biotech, and the animal studies will be done at the University of Kentucky. Upon completion, the commercialized transapical DLC with integrated compliance chambers will provide a less invasive paracorporeal pulsatile VAD with doubled efficiency. This technology can also be used in adults and may significantly impact cardiogenic shock/bridge to heart transplant management.