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Artificial Lungs for Lung Failure in the Era of COVID-19 Pandemic: Contemporary Review

Naito, Noritsugu; Shigemura, Norihisa
In patients with severe acute respiratory distress syndrome caused by coronavirus 2019 (COVID-19), mortality remains high despite optimal medical management. Extracorporeal membrane oxygenation (ECMO) has been widely used to support such patients. ECMO is not a perfect solution; however, there are several limitations and serious complications associated with ECMO use. Moreover, the overall short-term mortality rate of patients with COVID-19 supported by ECMO is high (~30%). Some patients who survive severe acute respiratory distress syndrome have chronic lung failure requiring oxygen supplementation, long-term mechanical ventilation, or ECMO support. Although lung transplant remains the most effective treatment for patients with end-stage lung failure from COVID-19, optimal patient selection and transplant timing for patients with COVID-19-related lung failure are not clear. Access to an artificial lung (AL) that can be used for long-term support as a bridge to transplant, bridge to recovery, or even destination therapy will become increasingly important. In this review, we discuss why the COVID-19 pandemic may drive progress in AL technology, challenges to AL implementation, and how some of these challenges might be overcome.
PMCID:10205060
PMID: 37046381
ISSN: 1534-6080
CID: 5507882

Robotic mitral valve repair with complete excision of mitral annular calcification [Editorial]

Naito, Noritsugu; Grossi, Eugene A; Nafday, Heidi B; Loulmet, Didier F
PMCID:9551376
PMID: 36237590
ISSN: 2225-319x
CID: 5361162

Combination of polycarboxybetaine coating and factor XII inhibitor reduces clot formation while preserving normal tissue coagulation during extracorporeal life support

Naito, Noritsugu; Ukita, Rei; Wilbs, Jonas; Wu, Kan; Lin, Xiaojie; Carleton, Neil M; Roberts, Kalliope; Jiang, Shaoyi; Heinis, Christian; Cook, Keith E
Blood contact with high surface area medical devices, such as dialysis and extracorporeal life support (ECLS), induces rapid surface coagulation. Systemic anticoagulation, such as heparin, is thus necessary to slow clot formation, but some patients suffer from bleeding complications. Both problems might be reduced by 1) replacing heparin anticoagulation with artificial surface inhibition of the protein adsorption that initiates coagulation and 2) selective inhibition of the intrinsic branch of the coagulation cascade. This approach was evaluated by comparing clot formation and bleeding times during short-term ECLS using zwitterionic polycarboxybetaine (PCB) surface coatings combined with either a potent, selective, bicyclic peptide inhibitor of activated Factor XII (FXII900) or standard heparin anticoagulation. Rabbits underwent venovenous ECLS with small sham oxygenators for 60 min using three means of anticoagulation (n = 4 ea): (1) PCB coating + FXII900 infusion, (2) PCB coating + heparin infusion with an activated clotting time of 220-300s, and (3) heparin infusion alone. Sham oxygenator blood clot weights in the PCB + FXII900 and PCB + heparin groups were 4% and 25% of that in the heparin group (p < 10-6 and p < 10-5), respectively. At the same time, the bleeding time remained normal in the PCB + FXII900 group (2.4 ± 0.2 min) but increased to 4.8 ± 0.5 and 5.1 ± 0.7 min in the PCB + heparin and heparin alone groups (p < 10-4 and 0.01). Sham oxygenator blood flow resistance was significantly lower in the PCB + FXII900 and PCB + heparin groups than in the heparin only group (p < 10-6 and 10-5). These results were confirmed by gross and scanning electron microscopy (SEM) images and fibrinopeptide A (FPA) concentrations. Thus, the combined use of PCB coating and FXII900 markedly reduced sham oxygenator coagulation and tissue bleeding times versus the clinical standard of heparin anticoagulation and is a promising anticoagulation method for clinical ECLS.
PMID: 33812214
ISSN: 1878-5905
CID: 4838732

First clinical use of a novel hypothermic storage system for a long-distance donor heart procurement

Naito, Noritsugu; Funamoto, Masaki; Pierson, Richard N; D'Alessandro, David A
PMID: 31420150
ISSN: 1097-685x
CID: 4091392

Quantification of interventricular dyssynchrony during continuous-flow left ventricular assist device support

Shimamura, Junichi; Nishimura, Takashi; Mizuno, Toshihide; Takewa, Yoshiaki; Tsukiya, Tomonori; Inatomi, Ayako; Ando, Masahiko; Umeki, Akihide; Naito, Noritsugu; Ono, Minoru; Tatsumi, Eisuke
Under continuous-flow left ventricular assist device (CF-LVAD) support, the ventricular volume change and cardiac cycle between the left ventricle (LV) and right ventricle (RV) become dyssynchronous due to the shortening of the LV systole. The purpose of this study was to quantify interventricular dyssynchrony based on different CF-LVAD support conditions and assess its relationship with LV unloading. In this study, we evaluated seven goats (body weight 44.5 ± 6.5 kg) with normal hearts. A centrifugal LVAD was implanted under general anesthesia. We inserted the conductance catheters into the left ventricle (LV) and right ventricle (RV) to assess the volume signal simultaneously. We defined the interventricular dyssynchrony as a signal (increase or decrease) of LV volume (LVV) change opposite to that of RV volume (RVV) (i.e., (dLVV/dt) × (dRVV/dt) < 0). The duration of interventricular dyssynchrony (DYS) was reported as the percentage of time that a heart was in a dyssynchronous state within a cardiac cycle. The mean DYS of normal hearts, hearts with LVAD clamp and hearts supported by LVADs with a bypass rate of 50%, 75% and 100% were 5.6 ± 1.6%, 8.7 ± 2.4%, 8.6 ± 2.8%, 15.1 ± 5.1%, and 25.6 ± 8.0%, respectively. Furthermore, the DYS was found to be associated with the degree of LV stroke volume reduction caused by LV unloading. These findings may be useful for understanding interventricular interactions and physiology during CF-LVAD support. Influences on the right ventricular function and heart failure models warrant further study.
PMID: 31203458
ISSN: 1619-0904
CID: 4006032

Miniaturized centrifugal ventricular assist device for bridge to decision: Preclinical chronic study in a bovine model

Shimamura, Junichi; Mizuno, Toshihide; Takewa, Yoshiaki; Tsukiya, Tomonori; Naito, Noritsugu; Akiyama, Daichi; Iizuka, Kei; Katagiri, Nobumasa; Nishimura, Takashi; Ono, Minoru; Tatsumi, Eisuke
We developed a novel miniaturized extracorporeal centrifugal pump "BIOFLOAT NCVC (Nipro Corporation Osaka, Japan) as a ventricular assist device (VAD) and performed a preclinical study that is part of the process for its approval as a bridge to decision by the pharmaceutical and medical device agencies. The aim of this study was to assess the postoperative performance, hemocompatibility, and anticoagulative status during an extended period of its use. A VAD system, consisting of a hydrodynamically levitated pump, measuring 64 mm by 131 mm in size and weighing 635 g, was used. We installed this assist system in 9 adult calves (body weight, 90 ± 13 kg): as left ventricular assist device (LVAD) in 6 calves and right ventricular assist device (RVAD) in 3 calves, for over 30 days. Perioperative hemodynamic, hematologic, and blood chemistry measurements were obtained and end-organ effects on necropsy were investigated. All calves survived for over 30 days, with a good general condition. The blood pump was operated at a mean rotational speed and a mean pump flow of 3482 ± 192 rpm and 4.08 ± 0.15 L/min, respectively, for the LVAD and 3902 ± 210 rpm and 4.24 ± 0.3 L/min, respectively, for the RVAD. Major adverse events, including neurological or respiratory complications, bleeding events, and infection were not observed. This novel VAD enabled a long-term support with consistent and satisfactory hemodynamic performance and hemocompatibility in the calf model. The hemodynamic performance, hemocompatibility, and anticoagulative status of this VAD system were reviewed.
PMID: 30891800
ISSN: 1525-1594
CID: 4006012

Zwitterionic poly-carboxybetaine coating reduces artificial lung thrombosis in sheep and rabbits

Ukita, Rei; Wu, Kan; Lin, Xiaojie; Carleton, Neil M; Naito, Noritsugu; Lai, Angela; Do-Nguyen, Chi Chi; Demarest, Caitlin T; Jiang, Shaoyi; Cook, Keith E
Current artificial lungs fail in 1-4 weeks due to surface-induced thrombosis. Biomaterial coatings may be applied to anticoagulate artificial surfaces, but none have shown marked long-term effectiveness. Poly-carboxybetaine (pCB) coatings have shown promising results in reducing protein and platelet-fouling in vitro. However, in vivo hemocompatibility remains to be investigated. Thus, three different pCB-grafting approaches to artificial lung surfaces were first investigated: 1) graft-to approach using 3,4-dihydroxyphenylalanine (DOPA) conjugated with pCB (DOPA-pCB); 2) graft-from approach using the Activators ReGenerated by Electron Transfer method of atom transfer radical polymerization (ARGET-ATRP); and 3) graft-to approach using pCB randomly copolymerized with hydrophobic moieties. One device coated with each of these methods and one uncoated device were attached in parallel within a veno-venous sheep extracorporeal circuit with no continuous anticoagulation (N = 5 circuits). The DOPA-pCB approach showed the least increase in blood flow resistance and the lowest incidence of device failure over 36-hours. Next, we further investigated the impact of tip-to-tip DOPA-pCB coating in a 4-hour rabbit study with veno-venous micro-artificial lung circuit at a higher activated clotting time of 220-300 s (N ≥ 5). Here, DOPA-pCB reduced fibrin formation (p = 0.06) and gross thrombus formation by 59% (p < 0.05). Therefore, DOPA-pCB is a promising material for improving the anticoagulation of artificial lungs. STATEMENT OF SIGNIFICANCE: Chronic lung diseases lead to 168,000 deaths each year in America, but only 2300 lung transplantations happen each year. Hollow fiber membrane oxygenators are clinically used as artificial lungs to provide respiratory support for patients, but their long-term viability is hindered by surface-induced clot formation that leads to premature device failure. Among different coatings investigated for blood-contacting applications, poly-carboxybetaine (pCB) coatings have shown remarkable reduction in protein adsorption in vitro. However, their efficacy in vivo remains unclear. This is the first work that investigates various pCB-coating methods on artificial lung surfaces and their biocompatibility in sheep and rabbit studies. This work highlights the promise of applying pCB coatings on artificial lungs to extend its durability and enable long-term respiratory support for lung disease patients.
PMCID:6633914
PMID: 31082571
ISSN: 1878-7568
CID: 4006022

Artificial Lungs for Lung Failure: JACC Technology Corner

Naito, Noritsugu; Cook, Keith; Toyoda, Yoshiya; Shigemura, Norihisa
Although lung transplantation is an effective treatment for end-stage lung failure, its limitations have led to renewed interest in artificial lung support for patients with lung failure. The use of ventricular assist devices has significantly improved the quality of life and survival of patients with end-stage heart failure. In contrast, there are no devices that can be used long term as destination therapy for end-stage lung failure, and there is a strong need for them. Extracorporeal membrane oxygenation is widely used as a temporary treatment for acute lung failure and as a bridge to lung transplant. Many patients with advanced lung failure cannot return home with good quality of life once they are hospitalized. In this review, the authors discuss the history, status, and future of artificial lungs, focusing on long-term artificial respiratory support as a destination therapy. Respiratory assist devices, such as artificial lungs, could eventually become analogous to ventricular assist devices.
PMID: 30261966
ISSN: 1558-3597
CID: 4006002

Left heart pressures can be the key to know the limitation of left ventricular assist device support against progression of aortic insufficiency

Iizuka, Kei; Nishinaka, Tomohiro; Naito, Noritsugu; Akiyama, Daichi; Takewa, Yoshiaki; Yamazaki, Kenji; Tatsumi, Eisuke
Aortic insufficiency (AI) is a worrisome complication under left ventricular assist device (LVAD) support. AI progression causes LVAD-left ventricular (LV) recirculation and can require surgical intervention to the aortic valve. However, the limitations of LVAD support are not well known. Using an animal model of LVAD with AI, the effect of AI progression on hemodynamics and myocardial oxygen metabolism were investigated. Five goats (Saanen 48 ± 2 kg) underwent centrifugal type LVAD, EVAHEART, implantation. The AI model was established by placing a vena cava filter in the aortic valve. Cardiac dysfunction was induced by continuous beta-blockade (esmolol) infusion. Hemodynamic values and myocardial oxygen extraction ratio (O2ER) were evaluated while changing the degree of AI which was expressed as the flow rate of LVAD-LV recirculation (recirculation rate). Diastolic aortic pressure was decreased with AI progression and correlated negatively with the recirculation rate (p = 0.00055). Systolic left ventricular pressure (LVP) and mean left atrial pressure (LAP) were increased with AI progression and correlated positively with the recirculation rate (p = 0.010, 0.023, respectively). LVP and LAP showed marked exponential increases when the recirculation rate surpassed 40%. O2ER was also increased with AI progression and had a significant positive correlation with the recirculation rate (p = 0.000043). O2ER was increased linearly, with no exponential increase. AI progression made it difficult to reduce the cardiac pressure load, worsening myocardial oxygen metabolism. The exponential increase of left heart pressures could be the key to know the limitation of LVAD support against AI progression.
PMID: 29464441
ISSN: 1619-0904
CID: 4005982

Preclinical animal study of the NIPRO-ventricular assist device for use in pediatric patients

Naito, Noritsugu; Takewa, Yoshiaki; Kishimoto, Satoru; Iizuka, Kei; Mizuno, Toshihide; Tsukiya, Tomonori; Ono, Minoru; Tatsumi, Eisuke
Although the outcomes of patients with end-stage heart failure treated with implantable left ventricular assist devices have improved, extracorporeal left ventricular assist devices continue to play an important role, especially in pediatric patients. The present study aimed to examine the long-term biocompatibility of a small-sized extracorporeal pneumatic left ventricular assist device (NIPRO-LVAD) used in a 30- to 90-day animal experiment. The NIPRO-LVAD was designed for pediatric patients or small-sized adults. The left ventricular assist device system was installed in four adult Shiba goats weighing 25.7 ± 4.78 kg via a left thoracotomy. The outflow graft was sewn to the descending aorta and the inflow cannula was placed in the left ventricle through the left ventricular apex. Oral antiplatelet (aspirin) and oral anticoagulation therapies (warfarin) were also administered. Three out of four animals survived for a 30-day period and two goats survived for 90 days. One animal was killed early because of low pump flow due to obstruction of the inflow cannula by a left ventricular endocardial vegetation. The blood pump exhibited sufficient hydrodynamic performance with blood flows of 1.5-2.0 L/min. The animals' laboratory values were within normal limits by postoperative day 7. There was no significant thrombus formation on the housing, diaphragm, or valves of the explanted pumps. Based on the biocompatibility demonstrated in this animal study, the explanted small-sized pump may be suitable for use in left ventricular assist device systems for pediatric patients.
PMID: 29177686
ISSN: 1619-0904
CID: 4005972