Progress towards permanent respiratory support.

PURPOSE OF REVIEW: Although lung transplantation stands as the gold standard curative therapy option for end-stage lung disease, the scarcity of available organs poses a significant challenge in meeting the escalating demand. This review provides an overview of recent advancements in ambulatory respiratory assist systems, selective anticoagulation therapies that target the intrinsic pathway, and innovative surface coatings to enable permanent respiratory support as a viable alternative to lung transplantation. RECENT FINDINGS: Several emerging ambulatory respiratory assist systems have shown promise in both preclinical and clinical trials. These systems aim to create more biocompatible, compact, and portable forms of extracorporeal membrane oxygenation that can provide long-term respiratory support. Additionally, innovative selective anticoagulation strategies, currently in various stages of preclinical or clinical development, present a promising alternative to currently utilized nonselective anticoagulants. Moreover, novel surface coatings hold the potential to locally prevent artificial surface-induced thrombosis and minimize bleeding risks. SUMMARY: This review of recent advancements toward permanent respiratory support summarizes the development of ambulatory respiratory assist systems, selective anticoagulation therapies, and novel surface coatings. The integration of these evolving device technologies with targeted anticoagulation strategies may allow a safe and effective mode of permanent respiratory support for patients with chronic lung disease.

Extended Duration of Impella 5.5 Support Does Not Adversely Impact Outcomes Following Heart Transplantation: A National Registry Analysis.

Prior studies assessing the effects of Impella 5.5 support duration on posttransplant outcomes have been limited to single-center case reports and series. This study evaluates the impact of Impella 5.5 support duration on outcomes following heart transplantation using the United Network for Organ Sharing database. Adult heart transplant recipients who were directly bridged to primary isolated heart transplantation with Impella 5.5 were included. The cohort was stratified into two groups based on the duration of Impella support: less than or equal to 14 and greater than 14 days. The primary outcome was 90 day posttransplant survival. Propensity score matching was performed. Sub-analysis was conducted to evaluate the impact of greater than 30 days of Impella support on 90 day survival. Three hundred thirty-two recipients were analyzed. Of these, 212 recipients (63.9%) were directly bridged to heart transplantation with an Impella support duration of greater than 14 days. The two groups had comparable 90 day posttransplant survival and complication rates. The comparable posttransplant survival persisted in a propensity score-matched comparison. In the sub-analysis, Impella support duration of greater than or equal to 30 days did not adversely impact 90 day survival. This study demonstrates that extended duration of support with Impella 5.5 as a bridge to transplantation does not adversely impact posttransplant outcomes. Impella 5.5 is a safe and effective bridging modality to heart transplantation.

Five-day Wearable Respiratory Support With a Novel Ambulatory Pulmonary Assist System in an Awake Ovine Model.

BACKGROUND: The pulmonary assist system (PAS) is a wearable respiratory support system that is currently under development for patients with chronic lung disease as a bridge to lung transplantation or as destination therapy. This study evaluates the long-term performance and biocompatibility of the PAS in a 5-d awake, ovine model. METHODS: The PAS was attached to normal sheep in venovenous configuration. Components of the PAS included a 0.9 m2 surface area oxygenator and a lightweight, battery-powered axial flow pump. The system was also tested using the Abbott PediMag as the control pump. Each sheep was supported on the PAS for 5 d with 2 L/min blood flow and 4 L/min sweep gas. Activated clotting times of 200-240 s were maintained using intravenous heparin. Pump performance, oxygen transfer, oxygenator resistance, and hematologic parameters were measured throughout the support. RESULTS: The PAS, either using the axial flow pump or PediMag (n = 4 each), was well tolerated by the sheep without signs of device-related organ damage or hemolysis. All the studies achieved the full, 5-d study duration. The oxygenator resistance remained consistent without significant clot formation in all experiments with an average resistance of 2.55 ±â€…0.10 mm Hg/(L/min). The system achieved an average oxygen transfer rate of 116.4 ±â€…5.5 mL/min, with an average Hb concentration of 9.2 ±â€…0.6 g/dL. White blood cell, platelet, and hematocrit levels also remained stable and within normal limits throughout the study period. CONCLUSIONS: The PAS provided 5 d of uncomplicated ambulatory respiratory support with minimal clot formation, stable gas exchange, blood flow resistance, and hematologic parameters.

Hemocompatibility Evaluation of a Novel Ambulatory Pulmonary Assist System Using a Lightweight Axial-Flow Pump.

The Pulmonary Assist System (PAS) is currently under development as a wearable respiratory assist system. In this study, the hemocompatibility of the PAS's axial-flow mechanical pump (AFP) was compared to other contemporary mechanical pumps in an acute ovine model. The PAS was attached to a normal sheep in a venovenous configuration using one of three pumps: 1) AFP, 2) ReliantHeart HeartAssist 5 (control), or 3) Abbott Pedimag (control) (n = 5 each). Each sheep was supported on the PAS for 12 hours with two L/minute of blood flow and four L/minute of sweep gas. Hemolysis, coagulation, inflammation, and platelet activation and loss were compared among the groups. In this study, the plasma-free hemoglobin (pfHb) was less than 10 mg/dl in all groups. The pfHb was significantly lower in the AFP group compared to other groups. There was no significant clot formation in the pumps and oxygenators in all groups. Furthermore, no significant differences in coagulation (oxygenator resistance, fibrinopeptide A), inflammation (white blood cell counts, IL-8), and platelet activation and loss (p-selectin, platelet counts) were observed among the groups (all, p > 0.05). This study demonstrates equivalent hemocompatibility of the PAS's AFP to other contemporary mechanical pumps with a reduced level of hemolysis on startup.