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Veno‐venous extracorporeal membrane oxygenation (VV ECMO) is an effective and proven adjunct support for various severe respiratory failures requiring invasive mechanical ventilation and cardiovascular support. In response to the rapidly increasing number of COVID‐19 patients in Japan, we launched an ECMO support team comprised of multidisciplinary experts including physicians, nurses, perfusionists, and bioethicists in preparation for the threat of a pandemic. From April 2 to July 15, 2020, Tokyo Medical and Dental University hospital treated 104 PCR confirmed COVID‐19 patients. Among those, 34 patients were admitted to intensive care unit (ICU) and 5 patients required VV ECMO. All management related to ECMO was decided by the ECMO support team in addition to participation of the ECMO support team in daily multidisciplinary rounds in the ICU. Median age was 54 years old. Duration from onset to mechanical ventilation (MV) and MV to ECMO were 8 and 7 days, respectively. Four patients (80%) were successfully weaned off from ECMO. One patient died after 81 days of ECMO run. Four patients were discharged and recovered to their prehospital quality of life without major disability. We achieved a high survival rate using ECMO in our low volume ECMO institution during the COVID‐19 pandemic. Multidisciplinary decision‐making and a team approach for the unclear pathology with an emerging infectious disease was effective and contributed to the survival rate. [ABSTRACT FROM AUTHOR]

For normothermic ex vivo heart perfusion (EVHP), a resting mode and working mode have been proposed. We newly developed a left ventricular assist device (LVAD) mode that supports heart contraction by co-pulse synchronized LVAD. Following resting mode during time 0 to 1 hour, pig hearts (n = 18) were perfused in either resting, working, or LVAD mode during time 1 to 5 hour, and then myocardial function was evaluated in working mode at 6 hour. The preservation ratio was defined as the myocardial mechanical function at 330 minute divided by the function at 75 minute. In LVAD mode, LVAD unloaded the pressure and the volume in the left ventricle in the systolic phase. The LVAD group was significantly associated with higher preservation ratios in cardiac output (resting, 33 ± 3; working, 35 ± 5; LVAD, 76% ± 5%; p < 0.001), stroke work, dP/dt maximum, and dP/dt minimum compared with the other groups. Glucose consumption was significantly reduced in the resting group. The LVAD group was significantly associated with higher myocardial oxygen consumption (resting, 2.2 ± 0.3; working; 4.6 ± 0.5; LVAD, 6.1 ± 0.5 mL O 2 /min/100 g, p < 0.001) and higher adenosine triphosphate (ATP) levels (resting, 1.1 ± 0.1; working, 0.7 ± 0.1; LVAD, 1.6 ± 0.2 μmol/g, p = 0.001) compared with the others. These data suggest that myocardial mechanical function was better preserved in LVAD mode than in resting and working modes. Although our data suggested similar glycolysis activity in the LVAD and working groups, the higher final ATP in the LVAD group might be explained by reduced external work in LVAD. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES This study aimed to evaluate the outcomes of tricuspid annuloplasty with/without additional edge-to-edge plications in patients with functional tricuspid regurgitation (TR) and to clarify the impact of tethering on surgical outcomes. METHODS This retrospective observational study included patients with moderate or greater functional TR who underwent initial tricuspid valve repair between January 2008 and December 2021. The patients were divided into 2 groups based on whether they had tethering (preoperative tethering area ≥0.75 cm2). All patients underwent annuloplasty, and edge-to-edge plications were added at the regurgitant leakage site identified by saline tests. The surgical outcomes of each group and the effect of tethering on recurrent moderate or greater TR were evaluated. RESULTS One hundred and thirty-three patients were included in this study. During the follow-up period of 55.3 (standard deviation: 44.9) months, the 5-year survival rates were 78.4% in patients without tethering and 76.1% in patients with tethering (P  = 0.78). The 5-year cumulative incidence rates of readmission for heart failure and recurrent TR were 10.8% and 1.3% in patients without tethering and 23.0% and 29.5% in patients with tethering, respectively (P  = 0.12 and <0.001). Multivariable analyses revealed that the preoperative and predischarge tethering areas predicted recurrent TR. A large tethering area remained postoperatively in patients with tethering. CONCLUSIONS In patients without tethering, annuloplasty and additional edge-to-edge plications are effective in avoiding recurrent TR with satisfactory midterm clinical outcomes. However, in patients with tethering, these procedures resulted in residual tethering, which could be leading to recurrent TR. [ABSTRACT FROM AUTHOR]

We have evaluated the feasibility of a newly developed single-use, magnetically levitated centrifugal blood pump, Med Tech Mag- Lev, in a 3-week extracorporeal membrane oxygenation ( ECMO) study in calves against a Medtronic Bio- Pump BPX-80. A heparin- and silicone-coated polypropylene membrane oxygenator MERA NHP Excelung NSH- R was employed as an oxygenator. Six healthy male Holstein calves with body weights of about 100 kg were divided into two groups, four in the Med Tech group and two in the Bio- Pump group. Under general anesthesia, the blood pump and oxygenator were inserted extracorporeally between the main pulmonary artery and the descending aorta via a fifth left thoracotomy. Postoperatively, both the pump and oxygen flow rates were controlled at 3 L/min. Heparin was continuously infused to maintain the activated clotting time at 200-240 s. All the Med Tech ECMO calves completed the study duration. However, the Bio- Pump ECMO calves were terminated on postoperative days 7 and 10 because of severe hemolysis and thrombus formation. At the start of the Med Tech ECMO, the pressure drop across the oxygenator was about 25 mm Hg with the pump operated at 2800 rpm and delivering 3 L/min flow. The PO2 of the oxygenator outlet was higher than 400 mm Hg with the PCO2 below 45 mm Hg. Hemolysis and thrombus were not seen in the Med Tech ECMO circuits (plasma-free hemoglobin [ PFH] < 5 mg/d L), while severe hemolysis ( PFH > 20 mg/d L) and large thrombus were observed in the Bio- Pump ECMO circuits. Plasma leakage from the oxygenator did not occur in any ECMO circuits. Three-week cardiopulmonary support was performed successfully with the Med Tech ECMO without circuit exchanges. The Med Tech Mag- Lev could help extend the durability of ECMO circuits by the improved biocompatible performances. [ABSTRACT FROM AUTHOR]

Last year, we reported in vitro pump performance, low hemolytic characteristics, and initial in vivo evaluation of a disposable, magnetically levitated centrifugal blood pump, MedTech Dispo. As the first phase of the two-stage in vivo studies, in this study we have carried out a 2-week in vivo evaluation in calves. Male Holstein calves with body weight of 62.4-92.2 kg were used. Under general anesthesia, a left heart bypass with a MedTech Dispo pump was instituted between the left atrium and the descending aorta via left thoracotomy. Blood-contacting surface of the pump was coated with a 2-methacryloyloxyethyl phosphorylcholine polymer. Post-operatively, with activated clotting time controlled at 180-220 s using heparin and bypass flow rate maintained at 50 mL/kg/min, plasma-free hemoglobin (Hb), coagulation, and major organ functions were analyzed for evaluation of biocompatibility. The animals were electively sacrificed at the completion of the 2-week study to evaluate presence of thrombus inside the pump, together with an examination of major organs. To date, we have done 13 MedTech Dispo implantations, of which three went successfully for a 2-week duration. In these three cases, the pump produced a fairly constant flow of 50 mL/Kg/min. Neurological disorders and any symptoms of thromboembolism were not seen. Levels of plasma-free Hb were maintained very low. Major organ functions remained within normal ranges. Autopsy results revealed no thrombus formation inside the pump. In the last six cases, calves suffered from severe pneumonia and they were excluded from the analysis. The MedTech Dispo pump demonstrated sufficient pump performance and biocompatibility to meet requirements for 1-week circulatory support. The second phase (2-month in vivo study) is under way to prove the safety and efficacy of MedTech Dispo for 1-month applications. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES The goal of this study was to evaluate the outcomes of patients with subvalvular procedures for functional tricuspid regurgitation (TR) with severe leaflet tethering. METHODS Of 175 patients who had tricuspid valve surgery between June 2016 and June 2021, a total of 17 patients with functional TR with a preoperative tethering height ≥8 mm underwent subvalvular procedures (annular repositioning [An-Rep]) to reduce septal leaflet tethering, papillary muscle relocation to reduce anterior leaflet tethering, and/or papillary muscle bundling [PMB] to reduce anterior and posterior leaflet tethering along with ring annuloplasty at our institution. A single subvalvular procedure was performed in 9 patients (An-Rep in 5 patients, PMB in 4 patients; group S), and a combination of subvalvular procedures was performed in 8 patients (An-Rep and papillary muscle relocation in 5 patients, An-Rep and PMB in 3 patients; group C). RESULTS Predischarge TR grades and tethering height were significantly improved (3.2 ± 1.3–1.0 ± 0.5, p = 0.001; 9.9 ± 2.5 mm–5.5 ± 2.8 mm, p < 0.001, respectively). An-Rep and PMB significantly reduced the postoperative closing angles of the septal and anterior leaflets, respectively. During the 20.4 ± 19.5-month follow-up period, the rates of freedom from death and moderate TR at 2 years were 41.7% in group S, and 71.4% in group C (p = 0.39), respectively. In group C, TR recurrence was not observed at 2 years postoperatively. CONCLUSIONS Subvalvular procedures were effective in reducing the predischarge TR grades and tethering height. The combination of subvalvular procedures might be a durable strategy to prevent recurrent TR. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES There are few reports on the rotational position of the aortic valve relative to the base of the left ventricle, and its influence on valve-sparing aortic root replacement (VSRR) has not been reported. Based on our experience with complications such as right atrial perforation and tricuspid valve injury, we investigated the cause of these complications in terms of morphological variations in the aortic root and its surrounding structures. METHODS The aortic valve rotation relative to the base of the left ventricle was assessed in 30 patients with tri-leaflet aortic valves who underwent VSRR. The influence of such anatomical variations on surgical procedures was investigated. RESULTS The aortic valve was positioned normally in 25 patients (83.3%), rotated counterclockwise in 4 (13.3%), and rotated clockwise in 1 patient (3.3%). In patients with a counterclockwise rotated aortic valve, the non-coronary sinus was the largest compared with other sinuses. This aortic valve rotation could be diagnosed by multidetector row computed tomography. In all patients who had difficulty in the external dissection of the right sinus of Valsalva, the aortic valve was counterclockwise rotated and forcible dissection had a risk of right atrial perforation and tricuspid valve injury. CONCLUSIONS Aortic valve rotation is an element that complicates VSRR. The rotational position of the aortic valve can be diagnosed preoperatively using multidetector row computed tomography and understanding the anatomy of the aortic valve related to rotational position help decide proper surgical decision-making in performing aortic root reconstruction procedure. [ABSTRACT FROM AUTHOR]

In this study, we have analyzed the changes in mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and the dynamic deformability and mechanical fragility of red blood cells (RBCs) in five male Holstein calves (body weight: 95.6 ± 10.8 kg) whose circulation was partially supported with a novel magnetically levitated extracorporeal centrifugal blood pump MedTech Dispo. One hour after the pumping has started, the MCV increased and the MCHC decreased by 1.064 ± 0.006 and 0.906 ± 0.050 times, respectively, as compared with those of the prepumped blood ( P < 0.05). The deformability index L/W, where L and W are the long and short axes of the two-dimensional RBC images, respectively, sheared by a cyclically reversing shear flow increased indicating that the RBCs pumped for 1 h exhibited more elastic characteristics ( P < 0.05). In addition, when the pumped blood cells were sheared for 30 min with a uniform shear stress of 25.38 Pa, the hemolysis level decreased dramatically as compared with the control blood, as more fragile RBCs were destroyed by pumping, leaving behind less fragile RBCs. All these characteristics of the RBCs exposed to continuous flow resemble those of young RBCs having larger MCV, lower MCHC, higher elasticity, and lower fragility. In conclusion, during continuous flow pumping, the RBCs having relatively lower threshold for hemolysis to mechanical shear stress generated by continuous flow blood pump (CFBP) are destroyed first and removed from circulation in the early stage of application of CFBP, thus leaving behind less fragile and stronger RBCs. [ABSTRACT FROM AUTHOR]

The TinyPump is an extracorporeal, magnetically driven centrifugal blood pump with its impeller suspended magnetically and hydrodynamically to provide short-term mechanical circulatory support for children and infants. We have previously demonstrated that the in vivo experiments of the experimental TinyPump showed acceptable stable performance at pump flows averaging around 1.0 L/min with low hemolytic and thrombogenic properties for up to 2 weeks. We present here the 1-month in vivo evaluation of the TinyPump, whose design was modified further for more durable operation. The pump was implanted as a left ventricular assist device in five goats (12.5-26.7 kg), with inflow inserted into the left ventricular apex and outflow anastomosed to the descending aorta. Five animals were supported for 110 pump days, with mean pump flow of 1.19 ± 0.03 L/min at a pump speed of 2679 ± 97 rpm. Two animals reached the scheduled end point of 30 days without device failure, and mean plasma-free hemoglobin was 1.7 ± 0.8 mg/dL. Hematologic and biochemical data of these two animals showed no evidence of cardiovascular, renal, or hepatic dysfunction. Although further experiments are needed, the modified TinyPump offers promise as a short-term mechanical circulatory support device in pediatric population. [ABSTRACT FROM AUTHOR]

Fractured tracheostomy tube is a rare, late complication. It typically occurs at the junction of metallic tube. We report an atypical case with laceration of the main trunk of a silastic tube after short period of use (10 days). [ABSTRACT FROM AUTHOR]

MedTech Dispo, a disposable maglev centrifugal blood pump with two degrees of freedom magnetic suspension and radial magnetic coupling rotation, has been developed for 1-month extracorporeal circulatory support. As the first stage of a two-stage in vivo evaluation, 2-week evaluation of a prototype MedTech Dispo was conducted. In in vitro study, the pump could produce 5 L/min against 800 mm Hg and the normalized index of hemolysis was 0.0054 ± 0.0008 g/100 L. In in vivo study, the pump, with its blood-contacting surface coated with biocompatible 2-methacryloyloxyethyl phosphorylcholine polymer, was implanted in seven calves in left heart bypass. Pump performance was stable with a mean flow of 4.49 ± 0.38 L/min at a mean speed of 2072.1 ± 64.5 rpm. The maglev control revealed its stability in rotor position during normal activity by the calves. During 2 weeks of operation in two calves which survived the intended study period, no thrombus formation was seen inside the pump and levels of plasma free hemoglobin were maintained below 4 mg/dL. Although further experiments are required, the pump demonstrated the potential for sufficient and reliable performance and biocompatibility in meeting the requirements for cardiopulmonary bypass and 1-week circulatory support. [ABSTRACT FROM AUTHOR]