Management of aortic valve insufficiency in patients with continuous-flow left ventricular assist device: a republication of the review published in Japanese Journal of Artificial Organs.

Since 2011, implantable ventricular assist devices have been a standard treatment for severe heart failure alongside heart transplantation in Japan. However, the limited availability of donors has led to a prolonged wait for transplants, now averaging 1719 days, intensifying the issue of aortic insufficiency in patients with continuous flow ventricular assist devices. These devices limit the opening of the aortic valve, leading to sustained closure and increased shear stress, which accelerates valve degradation. Risk factors for aortic insufficiency include having a smaller body surface area, being of advanced age, and the presence of mild aortic insufficiency prior to device implantation. In patients presenting with mild or moderate aortic regurgitation at the time of ventricular assist device implantation, interventions such as aortic valve repair or bioprosthetic valve replacement are performed with the aim of halting its progression. The choice of surgical procedure should be tailored to each patient's individual condition. The management of de novo aortic insufficiency in patients with continuous flow ventricular assist devices remains challenging, with no clear consensus on when to intervene. Interventions for significant aortic insufficiency typically consider the patient's symptoms and aortic insufficiency severity. De novo aortic insufficiency progression in continuous flow ventricular assist devices patients necessitates careful monitoring and intervention based on individual patient assessments and valve condition. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2023 (Vol. 52, No. 1, pp. 77-80), with some modifications.

The outcomes of a standardized protocol for extracorporeal mechanical circulatory support selection-left ventricular challenge protocol.

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.

Prognosis of Patients With Heart Failure Receiving Autologous Myoblast Patches　- Comparison of Single-Arm Trial Data to Registry Data.

BACKGROUND: Clinical studies in regenerative medicine remain insufficient in Japan due to ethical concerns regarding the control group and a lack of statistical methodology to evaluate efficacy in a small treatment group. This study evaluated the efficacy of autologous myoblast patch (AMP) treatment for heart failure using restricted mean survival time (RMST) analysis by comparing data from a small single-arm trial to epidemiological data from a registry.Methods and Results: The clinical trial arm included 55 patients with advanced ischemic cardiomyopathy who received an AMP between 2010 and 2020. The registry-based control group comprised 937 participants with severely impaired left ventricular function who were hospitalized for heart failure during the study period. Due to the limited number of patients, RMST analysis was used to compare survival between the 2 groups. Cox regression analyses revealed non-significant differences in survival between the groups at 3, 3.5, and 4 years. In contrast, RMST analyses revealed significant differences in survival at 3 years (P=0.008) and 3.5 (P=0.024) years, but not at 4 years. CONCLUSIONS: This small single-arm trial using RMST analyses was able to detect the efficacy of AMP transplantation for advanced heart failure (compared with a registry-based control group), with better survival until 3.5 years. This approach may be useful for efficacy analyses in regenerative medicine, where traditional clinical trials are difficult.

Prognostic impact of lung computed tomography density in cardiogenic shock patients with veno-arterial extracorporeal membrane oxygenation.

BACKGROUND: Pulmonary complications often occur in patients receiving veno-arterial extracorporeal membrane oxygenation (VA ECMO). However, the prognostic impact of lung damage has not been fully elucidated. METHODS: This single-center retrospective observational study targeted patients with cardiogenic shock who received VA ECMO between 2012 and 2021. This study included 65 patients who underwent chest computed tomography (CT) on VA ECMO, followed by escalation to central mechanical circulatory support (MCS) with left ventricular venting. The average density of lung CT images was measured using region-of-interest methods, and the primary endpoint was 180-day all-cause death after escalation to the central MCS. RESULTS: Twenty-two patients (34%) developed 180-day all-cause death. According to the Cox regression analysis, age (hazard ratio [HR], 1.08; 95% confidence interval [CI], 1.03-1.14; p = 0.001), ischemic etiology (HR, 5.53; 95% CI, 2.09-14.62; p < 0.001), duration of VA ECMO support (HR, 1.19; 95% CI, 1.00-1.40; p = 0.045), and lung CT density (≥ -481 Hounsfield unit [HU]) (HR, 6.33; 95% CI, 2.26-17.72; p < 0.001) were independently associated with all-cause death. Receiver operating characteristic curve analysis determined that lung CT density ≥ -481 HU is an optimal cutoff value for predicting all-cause death (area under the curve [AUC], 0.72). The 180-day overall survival rate for patients with high lung CT density (≥ -481 HU) was significantly lower than that for those with low lung CT density (< -481 HU) (44.4% vs. 81.6%, respectively, p = 0.002). CONCLUSIONS: Higher lung CT density could be a useful predictor of death in patients with VA ECMO requiring central MCS escalation.

A unique cuff-sewing method to implant heartmate3 LVAD for arrhythmogenic right ventricular cardiomyopathy, facilitated by 3D-printing heart model.

Implantation of left ventricular assist device (LVAD) for arrhythmogenic right ventricular (RV) cardiomyopathy is challenging associated with small LV cavity, laterally dislocated LV apex, thin and fragile RV free wall. A 43-year-old male with more than 10 years of medical treatment developed congestive heart failure related to biventricular failure. Durable LVAD was indicated to prevent further deterioration of the RV function, which would be exacerbated by progression of LV dysfunction. To simulate surgery, we printed-out a 3D heart model based on enhanced CT scanning study to identify the optimal coring position in the LV apex, by which the inflow directs the mitral valve. We then found that the mini-cuff of the HeartMate3 should be fixed in the paper-thin RV free wall by the usual cuff-sewing method. In the surgery, after the coring as planned, 5 pairs of interrupted sutures on the medial side were passed from the luminal side of the LV and then to the mini-cuff, and the lateral side of the mini-cuff was fixed with a continuous sutures, not to sew into the RV wall. The surgery was completed without complications with a good hemodynamics. The 3D heart model facilitated this unique method, indicating a usefulness of printed-out heart model for cases with unusual cardiac anatomy, which needs implantation of durable LVAD.

Early Outcomes of Intuity Rapid Deployment Aortic Valve Replacement Compared With Conventional Biological Valves in Japanese Patients.

BACKGROUND: This study aimed to elucidate the short-term surgical outcomes and hemodynamics of the Intuity valve compared to the standard bioprosthesis in Japanese patients.Methods and Results: Among the 307 consecutive patients who underwent aortic valve replacement (AVR) between February 2019 and March 2021, the Intuity valve was implanted in 95 patients (Intuity group) and a conventional stented bioprosthesis was implanted in 193 patients (conventional group). After propensity score matching, there was no significant difference in in-hospital mortality between the Intuity (n=2, 3%) and conventional groups (n=0, P=0.490). Operation, cardiopulmonary bypass, and aortic cross-clamping times were significantly shorter in the Intuity group. Although the effective orifice area index, trans-prosthetic mean pressure gradient, and peak velocity were similar between the 2 groups at 1 week postoperatively, the Intuity group showed a better mean pressure gradient and peak velocity at 1 year postoperatively. Complete atrioventricular block requiring permanent pacemaker implantation developed in 2 patients (3%) in the Intuity group and none in the conventional group (P=0.476). Mild or greater paravalvular leakage was present in 8 patients (13%) in the Intuity group and 2 patients (3%) in the conventional group (P=0.095). CONCLUSIONS: AVR using the Intuity valve in Japanese patients is satisfactory, with a better valve performance and a low incidence of complete atrioventricular block at 1 year postoperatively.

Transaortic Transcatheter Aortic Valve Replacement in Patients From a Single Institution　- Feasibility, Safety, and Midterm Outcomes.

BACKGROUND: Transaortic transcatheter aortic valve replacement (TAo-TAVR) is an alternative to peripheral or transapical TAVR. The procedural feasibility, safety, and midterm outcomes of TAo-TAVR were investigated in this study.Methods and Results:Eighty-four consecutive patients underwent TAo-TAVR from 2011 to 2021. Their median age was 83 years (interquartile range, 80-87 years). The Edwards SAPIEN and Medtronic CoreValve devices were used in 45 (53.6%) and 38 (45.2%) patients, respectively. The surgical approach was a right mini-thoracotomy in 43 patients (51.2%) and partial sternotomy in 4 patients (4.8%). The remaining 37 patients (44.0%) underwent full sternotomy because of concomitant off-pump coronary artery bypass grafting. VARC-3 device success was achieved in 77 patients (91.7%). Valve migration occurred in 3 patients (3.6%) using a first-generation CoreValve device, necessitating implantation of a second valve. No aortic annulus rupture, aortic dissection, or coronary orifice occlusion occurred. Conversion to surgery was required for 1 patient because of uncontrollable bleeding. Only 1 in-hospital death occurred. New pacemaker implantation was required in 6 patients (7.1%). Echocardiography at discharge showed no or trivial paravalvular leak (PVL) in 58 patients (69.0%), mild PVL in 23 (27.4%), and mild to moderate PVL in 2 (2.4%) patients. The 1- and 3-year incidence of cardiovascular death was 1.6% and 4.8%, respectively, with no structural valve deterioration. CONCLUSIONS: TAo-TAVR is feasible and safe with satisfactory midterm outcomes using both currently available devices.

Short-Term Outcomes of Magnetically Levitated Left Ventricular Assist Device in Advanced Heart Failure　- The Japanese Cohort.

BACKGROUND: The superiority of a fully magnetically levitated centrifugal-flow left ventricular assist device (LVAD) in terms of overall survival, stroke events and pump thrombosis has been demonstrated in previous international analyses, so we evaluated a Japanese cohort for the same.Methods and Results: This retrospective observational study was conducted at Osaka University Medical Hospital and the National Cerebral and Cardiovascular Center in Japan. A total of 75 consecutive patients who underwent HeartMate3 (HM3) implantation were included. The primary endpoint was on-device survival, and the secondary endpoint was the incidence of LVAD-related complications at 2 years. All parameters were compared with those of the previously performed HeartMate II (HMII) implantation in 197 cases. The on-device survival rates were 94.7% and 92.3% in the HM3 and HMII groups, respectively, at the 2-year follow-up (P=0.62). The rehospitalization-free rate after implantation was 61.8% in the HM3 group, which was significantly higher than that in the HMII group (relative risk, 0.35; 95% confidence interval [CI], 0.23-0.55; P<0.0001). Event-free survival rates from cerebral cerebrovascular events and pump thrombosis in the HM3 group were significantly higher than those in the HMII group, at 97.2% and 100%, respectively (relative risk, 0.14; 95% CI 0.03-0.58); P=0.0015 and relative risk, not calculated; P=0.049, respectively). CONCLUSIONS: Satisfactory short-term outcomes were observed after HM3 implantation in a Japanese cohort.

Long-term outcomes of autologous skeletal myoblast cell-sheet transplantation for end-stage ischemic cardiomyopathy.

We evaluated the cardiac function recovery following skeletal myoblast cell-sheet transplantation and the long-term outcomes after applying this treatment in 23 patients with ischemic cardiomyopathy. We defined patients as "responders" when their left ventricular ejection fraction remained unchanged or improved at 6 months after treatment. At 6 months, 16 (69.6%) patients were defined as responders, and the average increase in left ventricular ejection fraction was 4.9%. The responders achieved greater improvement degrees in left ventricular and hemodynamic function parameters, and they presented improved exercise capacity. During the follow-up period (56 ± 28 months), there were four deaths and the overall 5-year survival rate was 95%. Although the responders showed higher freedom from mortality and/or heart failure admission (5-year, 81% versus 0%; p = 0.0002), both groups presented an excellent 5-year survival rate (5-year, 93% versus 100%; p = 0.297) that was higher than that predicted using the Seattle Heart Failure Model. The stepwise logistic regression analysis showed that the preoperative estimated glomerular filtration rate and the left ventricular end-systolic volume index were independently associated with the recovery progress. Approximately 70% of patients with "no-option" ischemic cardiomyopathy responded well to the cell-sheet transplantation. Preoperative renal and left ventricular function might predict the patients' response to this treatment.

Heterogeneous reduction in regional wall stress after aortic valve replacement for aortic regurgitation: a distinct feature from aortic stenosis.

Geometric changes caused by volume reduction early after aortic valve replacement (AVR) for aortic regurgitation (AR) may not be uniform, resulting in varying regional end-systolic wall stress (ESS). This study compared changes in regional ESS between AR and aortic stenosis (AS) patients in the early phase following AVR. Computer-tomographic left ventricular (LV) angiography was performed for 10 patients with AR and 13 with AS before and three months after AVR. Regional ESS at the base, middle, and apex levels, each subdivided into four segments, was calculated based on the Janz equation: ESS = end-systolic LV pressure × local cross-sectional area of LV cavity/that of LV wall. Following AVR, median LV end-diastolic volume index fell from 106 to 69 ml/m2 (P = 0.001) in AR and 60 to 46 ml/m2 (P = 0.01) in AS patients. Global ESS also declined in both (AR, 186 to 124 kdyne/cm2, P = 0.02; AS, 187 to 108 kdyne/cm2, P < 0.001, respectively). Regional ESS was reduced in all segments in AS patients, accompanied by left ventricular ejection fraction (LVEF) improvement (71-80%, P = 0.02). In contrast, regional ESS in AR patients was heterogeneously reduced, as regional ESS fell significantly in the antero-septal wall but was unchanged in the infero-lateral wall, and LVEF remained unchanged (65 to 62%, P = 0.42). In the early postoperative phase after AVR, the loading condition of the regional LV wall in AR patients was characterized by a heterogeneous reduction in regional ESS in contrast to a uniform decline in AS patients.

Bridge from central extracorporeal life support is a risk factor of cerebrovascular accidents after durable left ventricular assist device implantation.

A bridging strategy from extracorporeal life support (ECLS) is effective in salvage and a bridge to recovery or to a durable left ventricular assist device (LVAD) for acute refractory heart failure. However, the correlation of this strategy with adverse events after durable LVAD implantation has not been fully investigated. This study enrolled 158 consecutive patients who had either the HeartMate II or HeartMate 3 and were implanted for bridge-to-transplantation. These devices were implanted as the primary mechanical support device in 115 patients, whereas the remaining 43 underwent LVAD implantation as the bridge from central ECLS. The primary study endpoint was all-cause mortality and cerebrovascular accidents (CVAs) after durable LVAD implantation, and the secondary endpoints were adverse events. Overall survival was not significantly different between the two groups. In contrast, the probability of CVAs was significantly greater in the bridge group than in the primary group (probability of CVAs, P = 0.002; log-rank test). In Cox multivariate logistic regression analysis, a bridge from central ECLS was an independent predictive factor of CVAs (hazard ratio 4.27, 95% confidence interval 1.43-12.8; P = 0.0095). Patients who are bridged from central ECLS are more frequently complicated by CVAs compared with those who undergo primary implantation of a durable LVAD, but survival is not significantly different between the two groups. A bridge from central ECLS is an independent predictive factor of CVAs post-implantation of an LVAD.

Efficacy of Off-Pump Coronary Artery Bypass Grafting With Concomitant Transcatheter Aortic Valve Replacement.

AIM: This study aimed to evaluate the early and intermediate-term outcomes of patients who underwent concomitant off-pump coronary artery bypass grafting (CABG) and transcatheter aortic valve replacement (TAVR). METHOD: Between January 2014 and June 2021, 49 patients underwent concomitant off-pump CABG and TAVR via median sternotomy (TAVRCAB group) and 143 underwent concomitant on-pump CABG and surgical aortic replacement. Of the 143 patients who underwent on-pump surgery, 80 (SAVRCAB group) were eligible for comparison. The composite event included all-cause death, heart failure rehospitalisation, repeat revascularisation, brain infarction, and repeat aortic valve replacement. RESULTS: The Society of Thoracic Surgeons' predicted risk for mortality and age were higher in the TAVRCAB group than in the SAVRCAB group (7.1% vs 3.1% [p<0.001]; 81 yrs vs 75 years [p<0.001], respectively), while the surgical time was shorter (289 min vs 352 min; p<0.001). There was no conversion to on-pump surgery in the TAVRCAB group. The postoperative maximum creatinine kinase-MB value was lower in the TAVRCAB group. There was no deep sternal wound infection or repeat revascularisation in either group. Hospital death and brain infarction developed in one patient (1.3%) each in the SAVRCAB group, but in no patients in the TAVRCAB group. The rates of freedom from the composite event were similar between the two groups during the follow-up period. CONCLUSIONS: Concomitant off-pump CABG and TAVR would be a less-invasive alternative procedure for treating intermediate or high surgical risk patients with aortic stenosis and coronary artery disease unsuitable for percutaneous coronary intervention.

[Beneficial Effects of the Modified Bicaval Anastomosis Technique for Orthotopic Heart Transplantation from a Size-Mismatched Donor:20-year Single Center Experience].

BACKGROUND: Size-mismatched heart transplantation( HTx) is associated with a risk of stenosis of the caval anastomosis site or low cardiac output syndrome. We developed a modified bicaval anastomosis technique( mBCAT) that achieved an adjustable caval anastomosis to compensate for the size mismatch. This study clarified clinical outcomes of HTx with mBCAT technique according to the degree of the size mismatch. METHODS AND RESULTS: This study consisted of 130 adult patients who underwent HTx with the mBCAT during a 22-year period and were followed up for at least 1 year. The cohort was divided into three groups according to the donor-to-recipient body weight ratio:<0.8, undersized group (n=19);0.8 ~1.3, size-matched group( n=89);and >1.3, oversized group( n=22). The undersized, size-matched, and oversized groups showed no significant differences in the rate of mild or worse tricuspid regurgitation on echocardiography at 1 month [ 1( 5.3%), 8( 9.0%), and 1( 4.6%), respectively;p=0.683] or the survival rate at 10 years( 100%, 96%, and 95%, respectively;p=0.452). The right heart catheter study revealed no pressure gradient across the orifices of both cavae in any patient. Additionally, the cardiac index immediately post-HTx was low in the undersized group, but improved over time in all groups, achieving the comparable value at 6 and 12 months post-HTx. CONCLUSIONS: The mBCAT prevented caval anastomosis-related complications in size-mismatched HTx and achieved excellent hemodynamics regardless of donor size.

Four-quadrant visualization of systemic circulatory equilibrium: right ventricular failure after left ventricular assist device implantation.

Right ventricular failure (RVF) is a serious adverse event after left ventricular assist device (LVAD) implantation but difficult to be characterized. This study aimed to visualize the dynamic circulatory equilibrium of acute RVF after LVAD implantation using a new four-quadrant diagram constructed by 1) cardiac function with central venous pressure (CVP) and cardiac index (CI) axes, 2) arterial vascular resistance with CI and mean blood pressure (mBP) axes, 3) pressure-diuretic function with mBP and net urinary sodium output (net U-Na) axes, and 4) venous compliance with net U-Na and CVP axes. Twenty LVAD patients were stratified into two groups, group S (≤10 days) and group L (>10 days), according to duration of postoperative inotropic support. The preoperative equilibrium loops were small in both groups. In the early postoperative phase, the loop in group S became dramatically enlarged to the left and upward, indicating increased CVP and CI by LVAD support. In group L, however, augmentation of CI was smaller despite similarly increased CVP, and net U-Na was decreased despite increased mBP. In the late postoperative phase, the equilibrium loop in group L recovered as similar to that seen in group S. Thus, acute RVF, as shown in group L, was characterized by the shape of the loop constructed by marked increased CVP, a relatively small increase in CI, and concomitant impairment of pressure natriuresis. In conclusion, the novel four-quadrant presentation of systemic circulatory equilibrium provides clear visualization of RVF after LVAD implantation, thus serving as a useful guide for prompt and optimal management.NEW & NOTEWORTHY Systemic circulatory dynamics are regulated by various negative feedback systems, including cardiac, arterial, venous, and renal functions, as well as autonomic nervous systems. The present novel four-quadrant presentation of their functions allows clear visualization of dynamic organ-to-organ interactions that can lead to a new circulatory equilibrium after therapeutic intervention. This new system physiological framework can serve as a useful guide for prompt and optimal management of circulatory malfunction.

Bilateral Internal Thoracic Artery Grafting Improves Survival for Severe Left Ventricular Dysfunction and Diabetes.

BACKGROUND: In patients with severe left ventricular (LV) dysfunction requiring coronary artery bypass grafting (CABG), the association between diabetic status and outcomes after surgery, as well as with survival benefit following bilateral internal thoracic artery (ITA) grafting, remain largely unknown.Methods and Results:Patients (n=188; mean [±SD] age 67±9 years) with LV ejection fraction ≤40% who underwent isolated initial CABG were classified into non-diabetic (n=64), non-insulin-dependent diabetic (NIDM; n=74), and insulin-dependent diabetic (IDM; n=50) groups. During follow-up (mean [±SD] 68±47 months), the 5-year survival rate was 84% and 65% among non-diabetic and diabetic patients, respectively (P=0.034). After adjusting for all covariates, both NIDM and IDM were associated with increased mortality, with hazard ratios (HRs) of 1.9 (95% confidence interval [CI] 1.0-3.7; P=0.049) and 2.4 (95% CI 1.2-4.8; P=0.016), respectively. Among non-diabetic patients, there was no difference in the 5-year survival rate between single and bilateral ITA grafting (86% vs. 80%, respectively; P=0.95), whereas bilateral ITA grafting increased survival among diabetic patients (57% vs. 81%; P=0.004). Multivariate analysis revealed that bilateral ITA was significantly associated with a decreased risk of mortality (HR 0.3; 95% CI 0.1-0.8; P=0.024). CONCLUSIONS: NIDM and IDM were significantly associated with worse long-term clinical outcome after CABG for severe LV dysfunction. Bilateral ITA grafting has the potential to improve survival in diabetic patients with severe LV dysfunction.

Complex HeartWare left ventricular assist device infection treated with pump exchange: clinical alert for the driveline location.

Infection is a major complication in patients with a left ventricular assist device (LVAD). Once a driveline exit-site infection (DLI) reaches the LVAD component, LVAD exchange may become necessary for radical treatment, although clinical results are not satisfactory. In this report, we describe two cases of LVAD infection successfully treated with pump exchange. During LVAD support, the DLI extended into the pump pocket and the outflow graft despite aggressive surgical debridement and negative pressure wound therapy. These two patients required LVAD exchange for radical treatment, because the estimated waiting period for heart transplantation was at least more than 1 year. The LVAD exchange was performed through median re-sternotomy, and the infected HeartWare ventricular assist device (HVAD) was completely removed under cardiopulmonary bypass. Then, a new LVAD covered with the omentum flap was implanted. These two patients were successfully bridged to heart transplantation after 10 months and 2 years of support without recurrence of infection. These two cases may suggest that the driveline of the HVAD needs to be kept away from the outflow graft to prevent refractory outflow graft infection.

Prediction of aortic valve regurgitation after continuous-flow left ventricular assist device implantation using artificial intelligence trained on acoustic spectra.

Significant aortic regurgitation (AR) is a common complication after continuous-flow left ventricular assist device (LVAD) implantation. Using machine-learning algorithms, this study was designed to examine valuable predictors obtained from LVAD sound and to provide models for identifying AR. During a 2-year follow-up period of 13 patients with Jarvik2000 LVAD, sound signals were serially obtained from the chest wall above the LVAD using an electronic stethoscope for 1 min at 40,000 Hz, and echocardiography was simultaneously performed to confirm the presence of AR. Among the 245 echocardiographic and acoustic data collected, we found 26 episodes of significant AR, which we categorized as "present"; the other 219 episodes were characterized as "none". Wavelet (time-frequency) analysis was applied to the LVAD sound and 19 feature vectors of instantaneous spectral components were extracted. Important variables for predicting AR were searched using an iterative forward selection method. Seventy-five percent of 245 episodes were randomly assigned as training data and the remaining as test data. Supervised machine learning for predicting concomitant AR involved an ensemble classifier and tenfold stratified cross-validation. Of the 19 features, the most useful variables for predicting concomitant AR were the amplitude of the first harmonic, LVAD rotational speed during intermittent low speed (ILS), and the variation in the amplitude during normal rotation and ILS. The predictive accuracy and area under the curve were 91% and 0.73, respectively. Machine learning, trained on the time-frequency acoustic spectra, provides a novel modality for detecting concomitant AR during follow-up after LVAD.

Total percutaneous biventricular assist device implantation for fulminant myocarditis.

We report an effective therapeutic approach of mechanical circulatory support for a patient with cardiogenic shock and respiratory insufficiency due to fulminant myocarditis. An Impella® 5.0 was utilized as a left ventricular assist device (VAD) and percutaneous veno-pulmonary extracorporeal membrane oxygenation (ECMO) as a right VAD. These devices were implanted without sternotomy or thoracotomy. Although a combination of Impella and veno-arterial ECMO has been reported as percutaneous biventricular support, there are concerns that this combination is not beneficial for myocardial recovery in patients with respiratory insufficiency, because Impella expels insufficiently oxygenated blood from the left ventricle to the coronary arteries. Our approach took advantage of percutaneous implantation of ECMO and temporary VAD, eliminating the drawbacks of both devices, thus providing a more effective and less invasive form of temporary biventricular support.

Impact of turbulent blood flow in the aortic root on de novo aortic insufficiency during continuous-flow left ventricular-assist device support.

Severe aortic insufficiency (AI) after implantation of continuous-flow left ventricular-assist device (LVAD) affects device performance and outcomes. However, the mechanism for the occurrence and progression of AI has not been elucidated. We investigated the impact of nonphysiological retrograde blood flow in the aortic root on AI after LVAD implantation. Blood flow pattern was analyzed in patients with and without AI (n = 3 each) who underwent LVAD implantation, by computational fluid dynamics with patient-specific geometries, which were reproduced using electrocardiogram-gated 320-slice computed tomographic images. The total volume of retrograde blood flow during one cardiac cycle (716 ± 88 mL) was higher and the volume of slow blood flow (<0.1 cm/s) (0.16 ± 0.04 cm3 ) was lower in patients with AI than in those without AI (360 ± 111 mL, P = .0495, and 0.49 ± 0.08 cm3 , P = .0495, respectively). No significant difference in wall shear stress on the aortic valve was observed between the groups. Patients with AI had a perpendicular anastomosis at the distal ascending aorta and the simulation in the modified anastomosis model of patients with AI showed that the retrograde blood flow pattern depended on the angle and position of anastomosis. Computational fluid dynamics revealed strong retrograde blood flow in the ascending aorta and aortic root in patients with AI after LVAD implantation. The angle and position of LVAD outflow anastomosis might impact retrograde blood flow and de novo AI after LVAD implantation.

Reparative macrophage transplantation for myocardial repair: a refinement of bone marrow mononuclear cell-based therapy.

Reparative macrophages play an important role in cardiac repair post-myocardial infarction (MI). Bone marrow mononuclear cells (BM-MNCs) have been investigated as a donor for cell therapy but with limited clinical success. These cells, however, may be utilized as a source for reparative macrophages. This translational study aimed to establish a robust in vitro protocol to produce functional reparative macrophages from BM-MNCs and to establish pre-clinical evidence of the efficacy of reparative macrophage transplantation for the treatment of MI. Mouse BM-MNCs were treated with M-CSF plus IL-4, IL-10, TGF-ß1 or combinations of these in vitro. The concomitant administration of M-CSF and IL-4 produced the highest rate and largest number of CD11b+F4/80+CD206+ reparative macrophages. Expression and secretion of tissue repair-related factors including IGF-1, TGF-ß1, VEGF and IL1-ra were remarkably enhanced in reparative macrophages compared to BM-MNCs. These cells were transplanted in a mouse MI model, resulting in evident improvement in cardiac function recovery, compared to BM-MNC transplantation. Histological studies showed that reparative macrophage transplantation enhanced myocardial tissue repair including augmented microvascular formation, reduced cardiomyocyte hypertrophy and attenuated interstitial fibrosis. Moreover, survival of reparative macrophages in the heart post-transplantation was increased compared to BM-MNCs. Reparative macrophage transplantation also increased host-derived reparative macrophages in part through TGF-ß secretion. In conclusion, concomitant M-CSF + IL-4 treatment effectively produced reparative macrophages from BM-MNCs in vitro. Transplantation of produced reparative macrophage achieved a superior therapeutic efficacy, compared to BM-MNC transplantation, through the enhanced quantity and quality of donor cell engraftment. Further development of this advanced cell-based therapy is warranted.