Journal of Artificial Organs最新文献

Left ventricular assist devices improve prognosis and quality of life, but exercise capacity remains limited in most patients after device implantation. Left ventricular assist device optimization through right heart catheterization reduces device-related complications. However, hemodynamic parameters associated with exercise capacity under optimized conditions. The aim of this study was to elucidate the predictors of exercise capacity from hemodynamic parameters at rest after left ventricular assist device optimization. We retrospectively reviewed 24 patients who underwent a ramp test with right heart catheterization, echocardiography and cardiopulmonary exercise testing more than 6 months after left ventricular assist device implantation. Pump speed was optimized to a lower setting that achieved right atrial pressure < 12 mmHg, pulmonary capillary wedge pressure < 18 mmHg, and cardiac index > 2.2 L/min/m², then exercise capacity was assessed by cardiopulmonary exercise testing. After left ventricular assist device optimization, the mean right atrial pressure, pulmonary capillary wedge pressure, cardiac index, and peak oxygen consumption were 7 ± 5 mmHg, 10 ± 7 mmHg, 2.7 ± 0.5 L/min/m², and 13.2 ± 3.0 mL/min/kg, respectively. Pulse pressure, stroke volume, right atrial pressure, mean pulmonary artery pressure, and pulmonary capillary wedge pressure were significantly associated with peak oxygen consumption. Multivariate linear regression analysis of factors predicting peak oxygen consumption revealed that pulse pressure, right atrial pressure, and aortic insufficiency remained independent predictors (β = 0.401, p = 0.007; β = - 0.558, p < 0.001; β = - 0.369, p = 0.010, respectively). Our findings suggests that cardiac reserve, volume status, right ventricular function, and aortic insufficiency predict exercise capacity in patients with a left ventricular assist device.

Hollow fiber membrane is incorporated into an extracorporeal membrane oxygenator (ECMO), and the function of the membrane determines the ECMO's functions, such as gas transfer rate, biocompatibility, and durability. In Japan, the membrane oxygenator to assist circulation and ventilation is approved for ECMO support. However, in all cases, the maximum use period has been only 6 h, and so-called 'off-label use' is common for ECMO support of severely ill COVID-19 patients. Under these circumstances, the HLS SET Advanced (Getinge Group Japan K.K.) was approved in 2020 for the first time in Japan as a membrane oxygenator with a two-week period of use. Following this membrane oxygenator, it is necessary to establish a domestic ECMO system that is approved for long-term use and suitable for supporting patients. Looking back on the evolution of ECMO so far, Japanese researchers and manufacturers have also contributed to the developments of ECMO globally. Currently, excellent membrane oxygenators and systems have been marketed by Japanese manufacturers and some of them are globally acclaimed, but in fact, most of the ECMO membranes are not made in Japan. Fortunately, Japan has led the world in the fields of membrane separation technology and hollow fiber membrane production. In the wake of this pandemic, from the perspective of medical and economic security, the practical use of purely domestic hollow fiber membranes and membrane oxygenators for long-term ECMO is imperative in anticipation of the next pandemic.

The management of right heart failure during durable left ventricular assist device (LVAD) support remains an unsolved issue so far. We had a 44-year-old male patient who was diagnosed with arrhythmogenic right ventricular cardiomyopathy and received HeartMate 3 LVAD (Abbott, USA) implantation as a bridge-to-transplant indication. The pump speed was adjusted as low as 4500 rpm to avoid the left ventricular narrowing and interventricular septal leftward shift. Riociguat was administered to decrease the afterload of the right ventricle and increase the preload of the left ventricle, in addition to the combination of neurohormonal blockers. Frequent low-flow alarm events eventually disappeared after amlodipine administration, and he was successfully returned to work. We here present a unique management in a patient with right heart failure due to arrhythmogenic right ventricular cardiomyopathy during HeartMate 3 LVAD support.

Purpose: Bleeding complication is a critical risk factor for outcomes of acute heart failure patients requiring mechanical circulatory support (MCS), including percutaneous catheter-type heart pumps (Impella). The Japanese registry for Percutaneous Ventricular Assist Device (J-PVAD) is an ongoing, large-scale, real-world registry to characterize Japanese patients requiring Impella. Here we analyzed bleeding complication profiles in patients who received Impella.

Methods: All consecutive Japanese patients who received Impella from October 2017 to January 2020 were enrolled. The 30-day survival and bleeding complications were analyzed.

Results: A total of 1344 patients were included: 653 patients received Impella alone, 685 patients received a combination of veno-arterial extracorporeal membrane oxygenation and Impella (ECPELLA), and 6 patients had failed Impella delivery. Overall 30-day survival was 67.0%, with Impella alone at 81.9% and ECPELLA at 52.7%. Overall bleeding/hematoma adverse events with a relation or not-excluded relation to Impella was 6.92%. Among them, the rates of hematoma and bleeding from medical device access sites were 1.41% and 4.09%, respectively. There was no difference between etiologies for these events.

Conclusion: This study represents the first 3-year survival and the safety profile focused on bleeding adverse events from the J-PVAD registry. The results show that the real-world frequency of bleeding adverse events for patients who received Impella was an expected range from previous reports, and future real-world studies should aim to expand this data set to improve outcomes and adverse events.

Abstract

Since the risk factors for heparin resistance (HR) before cardiopulmonary bypass (CPB) have not been fully clarified, this study investigated the contributing factors for HR after the initial unfractionated heparin (UFH) dose of 500 IU/kg. We retrospectively analyzed the data of 371 patients who underwent CPB surgery, with the initial UFH dose of 500 IU/kg, between May 2017 and December 2021. We defined HR as the failure to achieve activated clotting time (ACT) of > 480 s after the initial UFH dose of 500 IU/kg. HR was observed in 36 patients (9.7%) (HR group), while HR was not observed in 335 patients (control group). The HR group included significantly more patients with preoperative use of UFH, with significantly higher white blood cell counts, fibrinogen, fibrinogen degradation products, d-dimer, and C-reactive protein, and lower hemoglobin and albumin. The multivariable logistic regression analysis identified albumin (OR: 3.09, 95% CI 1.3504–7.0845, p = 0.0075) and fibrinogen (OR: 0.99, 95% CI 0.9869–0.9963, p = 0.0003) as independent predictors for HR. Using the Youden index, the cutoffs of albumin and fibrinogen were calculated as 3.8 g/dL and 303 mg/dL, respectively. The receiver operating characteristic curves showed the predictive performance of albumin (area under the curve (AUC): 0.78, sensitivity: 65%, specificity: 81%) and fibrinogen (AUC: 0.77, sensitivity: 56%, specificity: 88%). The incidence of HR after the initial UFH dose of 500 IU/kg was 9.7%. The preoperative albumin < 3.8 g/dL and fibrinogen > 303 mg/dL were independent predictors for HR.

Research is lacking on the effect of intraoperative pelvic tracker displacement relative to the pelvis on cup orientation accuracy in computed tomography (CT)-based navigation (CTN) or multivariable analysis to detect factors associated with CTN accuracy. Here, we asked: (1) how pelvic tracker displacement influences the CTN accuracy of cup orientation in total hip arthroplasty (THA)? and (2) what factors are associated with CTN accuracy on multivariable analysis? Regarding cup orientation in 446 THA procedures using CTN, we evaluated clinical error defined as the difference between postoperative measurement and preoperative planning and measurement error defined as the difference between postoperative and intraoperative measurements. Multivariable regression analyses detected the associated factors. Subjects with an intraoperative tracker displacement of < 2 mm were classified in the verified group. Mean absolute clinical and measurement errors were < 1.5° in the verified group, whereas the measurement error of 2.6° for cup inclination and 1.3° for anteversion was larger in the non-verified versus verified group. Tracker displacement and screw fixation were associated with larger clinical errors, while tracker displacement and surgeon inexperience were associated with larger measurement errors. Clinical and measurement accuracies were high for CTN cup placement with rigid pelvic tracker fixation.

Understanding the interaction between macrophages and biomaterials is important for the creation of new biomaterials and the development of technologies to control macrophage function. Since macrophages are strongly adhesive, caution is required when performing in vitro evaluations. Similarly, when THP-1 cells, macrophage precursor cells, are differentiated into macrophages using phorbol-12-myristate-13-acetate (PMA), it becomes difficult to detach them from the adherent substrate, which has been a problem on investigation of immunological responses to biomaterials. In this study, the interaction of THP-1 cell-differentiated macrophages with biomaterials was analyzed based on a new method of seeding THP-1 cells. THP-1 cells were cultured in static and rotation culture without and with PMA. In undifferentiated THP-1 cells, there was no change in cellular function between static and rotation cultures. In rotation culture with PMA, THP-1 cells differentiated and formed macrophage aggregates. IL-1β and MRC1 expression in macrophage aggregates was examined after differentiation and M1/M2 polarization. Macrophage aggregates in rotation culture tended to be polarized toward M2 macrophages compared with those in static culture. In the evaluation of the responses of macrophage aggregates to several kinds of polymeric materials, macrophage aggregates showed different changes in MRC1 expression over time at 30, 50, and 70 rpm. Rotation speed of 30 rpm was considered most appropriate condition in that it gave stable results with the same trend as obtained with static culture. The use of macrophage aggregates obtained by rotational culture is expected to provide new insights into the evaluation of inflammatory properties of biomaterials.

There are no criteria for surgical mechanical circulatory system (MCS) selection for acute heart failure. Since 2021, we have utilized cardiopulmonary bypass system to assess patients' heart and lung condition to inform surgical MCS selection. we aimed to retrospectively analyze the outcomes of treatments administered using our protocol. We analyzed the data of 19 patients who underwent surgical MCS implantation. We compared patients' characteristics across the biventricular-assist device (BiVAD), central Y-Y extracorporeal membrane oxygenation (ECMO), central ECMO, and left VAD (LVAD) systems. Patients' diagnoses included fulminant myocarditis (47.4%), dilated cardiomyopathy (21.1%), acute myocardial infarction (15.8%), infarction from aortic dissection (5.3%), doxorubicin-related cardiomyopathy (5.3%), and tachycardia-induced myocarditis (5.3%). Eight patients (42.1%) underwent LVAD implantation, 1 (5.2%) underwent central ECMO, 4 (21.1%) underwent BiVAD implantation, and 6 (31.6%) underwent central Y-Y ECMO. 48 h after surgery, both the pulmonary arterial and right atrial pressures were effectively controlled, with median values being 19.0 mmHg and 9.0 mmHg, respectively. No patients transitioned from LVAD to BiVAD in the delayed period. Cerebrovascular events occurred in 21.1%. Successful weaning was achieved in 11 patients (57.9%), and 5 patients (26.3%) were converted to durable LVAD. Two-year cumulative survival was 84.2%. Our protocol showed good results for device selection in patients with heart failure, and device selection according to this protocol enabled good control of the pulmonary and systemic circulations.

The patient was diagnosed with perimembranous ventricular septal defect (VSD). She underwent VSD closure and muscle bundle resection across right ventricular outflow tract at the age of 3 months. Since then, she had suffered from severe heart failure and complete heart block. Permanent pacemaker generator was implanted in the left hypochondrium. She was depended on continuous catecholamine administration, so transferred to our hospital for further management. On arrival, her body weight was 5686 g (− 2.7 SD). She underwent Excor pediatric left ventricular assist device implantation at the age of 9 months. Because the position of the left ventricular assist device cannula interfered with the pacemaker, herein, the pacemaker pocket was newly created in the left thoracic cavity. An 1 mm in thickness of expanded polytetrafluoroethylene sheet was trimmed and sutured under the anterolateral wall of left thoracic cavity as a pacemaker pocket. Bipolar ventricular lead was sutured on left ventricular apex and basal wall to face each other, mimicking cardiac regeneration therapy. Even though she unfortunately required right diaphragmatic plication for iatrogenic phrenic nerve palsy, her respiratory function was well maintained; therefore, secondary right heart failure was not observed. Her cardiopulmonary function was quite stable until post-operative day 275 when the patient was transferred to another hospital for heart transplantation.

Implantation of continuous-flow left ventricular assist device in a narrow lumen is technically challenging to secure an optimal support. We experienced a patient with the transposition of the great arteries after the Senning procedure who was initially implanted with Jarvik 2000®. She presented with worsening heart failure symptoms 2 years after implanting Jarvik 2000®. We assumed that the inflow cannula was stuck in the highly developed trabeculae on the interventricular septum, which disturbed the VAD to maintain an expected support. After converting to the EVAHEART® 2, we successfully obtained an adequate inflow. We consider that the tipless cannula of EVAHEART® 2 is the most suitable when there is no sufficient room to place a conventional inflow cannula in the systemic ventricle.