Feasibility of an animal model for long-term mechanical circulatory support with Impella 5.5 implanted through carotid artery access in sheep.

Impella is a mechanical circulatory support device of a catheter-based intravascular microaxial pump for left ventricular support and unloading. However, nonclinical studies assessing the effects of the extended duration of left ventricular unloading on cardiac recovery are lacking. An animal model using Impella implanted with a less invasive procedure to enable long-term support is required. This study aimed to evaluate the feasibility of an animal model for long-term support with Impella 5.5 implanted through carotid artery access in sheep.Impella 5.5 was implanted in four sheep through the proximal region of the left carotid artery without a thoracotomy, and myocardial injuries were induced by coronary microembolization. Support by Impella 5.5 was maintained for 4 weeks, and the animals were observed. The position of Impella 5.5 and cardiac function was evaluated using cardiac computer tomography at 2 and 4 weeks after implantation.All four animals completed the 4-week study without major complications. The discrepancy in the Impella 5.5 flow rate between the conscious and anesthetized states was observed depending on the device's position. Animals in whom the inflow was above the left ventricular papillary muscle had a relatively high flow rate under the maximum performance level without a suction alarm during the conscious state. Pathological changes in the aortic valve were observed. Cardiac function under the minimum performance level was observed with no remarkable deterioration.The animal model with myocardial injuries supported for 4 weeks by Impella 5.5 implanted through carotid artery access in sheep was feasible.

Coronary microembolization sheep model by adjusting the number of microspheres based on coronary blood flow.

BACKGROUND: A heart failure (HF) model using coronary microembolization in large animals is indispensable for medical research. However, the heterogeneity of myocardial response to microembolization is a limitation. We hypothesized that adjusting the number of injected microspheres according to coronary blood flow could stabilize the severity of HF. This study aimed to evaluate the effect of microsphere injection based on the left coronary artery blood flow in an animal model. METHODS: Microembolization was induced by injecting different numbers of microspheres (polystyrene, diameter: 90 µm) into the left descending coronary artery of the two groups of sheep (400 and 600 times coronary blood flow [ml/min]). Hemodynamic parameters, the pressure-volume loop of the left ventricle, and echocardiography findings were examined at 0.5, 1.5, 3.5, and 6.5 h after microembolization. RESULTS: End-diastolic pressure and normalized heart rate increased over time, and were significantly higher in 600 × coronary blood flow group than those in 400 × coronary blood flow group (p = 0.04 and p < 0.01, respectively). The maximum rate of left-ventricular pressure rise and normalized stroke volume decreased over time, and were significantly lower in 600 × coronary blood flow group than those in 400 × coronary blood flow group (p < 0.01 and p < 0.01, respectively). The number of microspheres per coronary blood flow was significantly correlated with the decrease in stroke volume and the maximum rate of left ventricular pressure rise in 6.5 h (r = 0.74, p = 0.01 and r = 0.71, p = 0.02, respectively). CONCLUSIONS: Adjusting the number of injected microspheres based on the coronary blood flow enabled the creation of HF models with different degrees of severity.

Numerical simulation of the leakage flow of the hydrodynamically levitated centrifugal blood pump for extracorporeal mechanical circulatory support systems.

Extracorporeal centrifugal pumps are widely used in various forms of mechanical circulatory support, including extracorporeal membrane oxygenation and ventricular assist device. A durable centrifugal pump was developed by implementing a new hydrodynamic bearing design that prevents the impeller from touching to the casing wall and provides sufficient washout through the pump to prevent thrombus formation in the pump. The hydrodynamic bearings of the pump are composed of dual annular paths located on both sides of the impeller. Computational fluid dynamics analyses were performed on the flow field inside the pump to estimate the leakage flow through the gap and its impact on the pump efficiency and biocompatibility. The calculations were performed for motor speeds from 3000 to 5000 rpm and flow rates from 1.0 to 9.0 L/min. The leakage flow increased linearly with increasing pressure head of the pump, and the total leakage flow ranged from 2.0 to 27.3% of the total flow. The average wall shear stresses in the casing bottom ranged from 10.6 to 40.9 Pa. The leakage flow of the centrifugal pump with the hydrodynamically levitated impeller had a measurable impact on hydraulic energy losses while enhancing the washout flow to achieve good anti-thrombogenicity.

Feasibility study of an artificial placenta system consisting of a loop circuit configuration extracorporeal membrane oxygenation with a bridge circuit in the form of the umbilical arterial-venous connection.

We developed a new artificial placenta (AP) system consisting of a loop circuit configuration extracorporeal membrane oxygenation (ECMO) with a bridge circuit designed to be applied to the fetus in the form of an umbilical arterial-venous connection. We aimed to evaluate the feasibility of the AP system by performing a hydrodynamic simulation using a mechanical mock circulation system and fetal animal experiment. The effect of the working condition of the AP system on the fetal hemodynamics was evaluated by hydrodynamic simulation using a mechanical mock circulation system, assuming the weight of the fetus to be 2 kg. The AP system was introduced to two fetal goats at a gestational age of 135 days. The general conditions of the experimental animals were evaluated. The mock simulation showed that in an AP system with ECMO in the form of an umbilical arterial-venous connection in series, it could be difficult to maintain fetal hemodynamics when high ECMO flow was applied. The developed AP system could have high ECMO flow with less umbilical blood flow; however, the possibility of excessive load on the fetal right-sided heart should be noted. In the animal experiment, kid 1 (1.9 kg) was maintained on the AP system for 12 days and allowed to grow to term. In kid 2 (1.6 kg), the AP system could not be established because of the occlusion of the system by a thrombus. The developed AP system was feasible under both in vitro and in vivo conditions. Improvements in the AP system and management of the general fetal conditions are essential.

Computed tomography perfusion in patients of stroke with left ventricular assist device.

Left ventricular assist devices (LVAD) are widely applied for patients with severe heart failure as a bridge to heart transplantation as well as destination therapy. Patients with implanted LVAD have an increased risk of cerebral thrombosis and computed tomographic perfusion (CTP) has the potential to be performed for early diagnosis and treatment of acute ischemic stroke (AIS), including interventional thrombectomy. Here, we report our series of CTP examination in patients having suspected AIS after LVAD implantation. We retrospectively investigated 33 contrast-enhanced CTPs from January 2017 to December 2018 which were performed in 12 cases of patients because of possible neurological findings leading to suspected AIS during LVAD circulatory support who did not have definite ischemic findings nor intracerebral hemorrhage on non-contrast computed tomography. AIS with perfusion disturbance area was diagnosed in 11 (33.3%) out of a total of 33 CTPs in 4 (33.3%) out of 12 patients. Endovascular thrombectomy (EVT) was successfully performed in this research study four times for three patients. CTP was able to detect and determine the indication for EVT without serious complications. CTP could potentially be the first-choice assessment for early diagnosis of AIS with recoverable ischemic penumbra in patients with LVAD implantation.

Evaluation of cardiac beat synchronization control for a rotary blood pump on valvular regurgitation with a mathematical model.

We have studied the cardiac beat synchronization (CBS) control for a rotary blood pump (RBP) and revealed that it can promote pulsatility and reduce cardiac load. Besides, patients with LVAD support sometimes suffer from aortic and mitral regurgitation (AR and MR). A control method for the RBP should be validated in wider range of conditions to clarify its benefits and pitfalls prior to clinical application. In this study, we evaluated pulsatility and cardiac load reduction obtained with the CBS control on valvular failure conditions with a mathematical model. Diastolic assist could reduce cardiac load on the left ventricle by decreasing external work of the ventricle even in MR cases while it was not so effective in AR cases. Systolic assist can still promote pulsatility in AR and MR cases; however, aortic valve function should be carefully confirmed since pulse pressure can be wider not due to systolic assist but to AR.

Assessment of ocular blood flow in continuous-flow ventricular assist device by laser speckle flowgraphy.

Although the influence of continuous-flow left ventricular assist device (CF-LVAD) support on peripheral circulation has been widely discussed, its monitoring modalities are limited. The aim of this study was to assess the peripheral circulation using the laser speckle flowgraph (LSFG) which can quantitatively measure the ocular blood flow. We implanted a centrifugal CF-LVAD (EVAHEART®; Sun Medical Technology Research Corporation, Nagano, Japan) in five adult goats (body weight 44.5 ± 2.9 kg) under general anesthesia. The waveform of the central retinal artery using the mean blur rate (MBR) for ocular blood velocity and fluctuations as a parameter of pulsatility were obtained before LVAD implantation and after LVAD full-bypass support. The MBR waveform and LSFG fluctuation data were compared with the waveform and pulsatility index of the external carotid artery using an ultrasonic flow meter to evaluate circulatory patterns at different levels. The MBR waveform pattern of the central retinal artery was pulsatile before LVAD implantation and less pulsatile under LVAD full bypass. The fluctuation was 14.7 ± 1.86 before LVAD implantation and 3.85 ± 0.61 under LVAD full bypass (p < 0.01), respectively. The fluctuations of LSFG showed a strong correlation with the pulsatility index of the external carotid artery meaning that similar changes in circulatory pattern were observed at two different levels. Measuring the ocular blood flow using LSFG has potential utility for the assessment of the status of the peripheral circulation and its pulsatility during CF-LVAD.

Impact of Recurrent Ventricular Tachyarrhythmia on Outcome in Japanese Heart Transplant Candidates With a Left Ventricular Assist Device.

BACKGROUND: Recurrent ventricular tachyarrhythmias (VTA) are "A factor" modifiers in the Interagency Registry for Mechanically Assisted Circulatory Support profile. The effect of recurrent VTA on clinical outcome, however, is controversial. We evaluated the impact of recurrent VTA on outcome in Japanese heart transplant candidates with a left ventricular assist device (LVAD). Methods and Results: Sixty-six adult patients with advanced heart failure who were listed for heart transplantation between January 2005 and October 2017 were enrolled in the study. Recurrent VTA (modifier A status) was defined as a sustained ventricular tachycardia or fibrillation that required implantable cardioverter defibrillator shocks or an external defibrillator more than twice weekly. The primary outcome was death from any cause. The secondary outcomes were the first occurrence of VTA and recurrent VTA after LVAD implantation. Sixteen patients (24%) met the criteria for modifier A status, and 15 patients had an LVAD implanted. During a median follow-up of 1,124 days, 21 of 60 patients with an LVAD died. There was a significantly higher mortality rate in LVAD patients with modifier A status than in those who did not meet the modifier A criteria. On multivariate analysis, patients with modifier A status had an increased risk of mortality (HR, 3.43; 95% CI: 1.30-8.61, P=0.001). CONCLUSIONS: Recurrent VTA might be a marker for worse outcome in Japanese heart transplant candidates with an LVAD.

Outflow graft anastomosis site design could be correlated to aortic valve regurgitation under left ventricular assist device support.

Aortic valve regurgitation (AR) is a critical complication during circulatory support with a left ventricular assist device (LVAD). The time-course of AR and related factors, including outflow graft anastomosis site design, were investigated. Twenty-three patients who had continuous-flow LVAD implantation and were supported for more than 6 months were investigated. AR grade (none, 0; trivial, 0.5; mild, 1; mild-moderate, 1.5; moderate, 2; moderate-severe, 2.5; severe, 3) and aortic valve opening were evaluated with echocardiography. Computed tomography was performed to all the patients postoperatively. The angle of the outflow graft to the aorta (O-A angle, parallel 0; tangent 90°, 0-180°), aortic diameter at the anastomosis site, sino-tubular junction (STJ) diameter, distance between the STJ and the anastomosis site, and distance between the anastomosis site and the brachiocephalic artery were measured. The patients' age was 38 ± 11 years. Support duration was 686 ± 354 days. Mean AR grade after continuous-flow LVAD implantation was increased to around mild and was maintained thereafter. No patient needed any intervention to the aortic valve. The aortic valves of 82.6% of patients were closed continuously. The O-A angle (83 ± 14) was positively correlated with maximum AR grade (p = 0.0095). The O-A angle was significantly smaller in patients with maximum AR grade of 1 or less (77 ± 9°) than in those with 1.5 or greater (94 ± 15°, p = 0.021). The other CT measurements had no correlation with AR grade. In conclusion, the O-A angle was correlated with AR grade progression. The O-A angle appears to be one of the important factors related to AR under continuous-flow LVAD support.

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

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.

The angle of the outflow graft to the aorta can affect recirculation due to aortic insufficiency under left ventricular assist device support.

Aortic insufficiency (AI) is a crucial complication during continuous-flow left ventricular assist device (LVAD) support. Our previous clinical study suggested that a larger angle between the outflow graft and the aorta (O-A angle) could cause AI progression. This study examined the effect of the O-A angle on the hemodynamics of AI under LVAD support in an acute animal experimental model. An LVAD was installed in seven calves, with the inflow cannula inserted from the LV apex and with the outflow graft sutured at the ascending aorta. The AI model was made using a temporary inferior vena cava filter inserted from the LV apex and placed at the aortic valve. Cardiac dysfunction was induced by continuous beta-blocker infusion. Hemodynamic values and the myocardial oxygen extraction rate (O2ER) were evaluated at three O-A angles (45°, 90°, and 135°) over three levels of AI (none, Sellers I-II AI, and Sellers III-IV AI). The recirculation rate, defined as the percentage of regurgitation flow to LVAD output, was calculated. Systemic flow tended to decrease with a larger O-A angle. The recirculation rate was significantly increased with a larger O-A angle (22, 23, and 31% at 45°, 90°, and 135° in Sellers III-IV AI, respectively). Coronary artery flow was decreased at a larger O-A angle (86, 76 and 75 mL/min at 45°, 90°, and 135° in Sellers I-II AI, respectively, and 77, 67, and 56 mL/min at 45°, 90°, and 135° in Sellers III-IV AI, respectively). O2ER tended to increase with a larger O-A angle (40, 43, and 49% at 45°, 90°, and 135° in Sellers III-IV AI, respectively). A larger O-A angle can increase the recirculation due to AI and can be disadvantageous to LVAD-AI hemodynamics and myocardial oxygen metabolism.

The influence of pump rotation speed on hemodynamics and myocardial oxygen metabolism in left ventricular assist device support with aortic valve regurgitation.

Aortic valve regurgitation (AR) is a serious complication under left ventricular assist device (LVAD) support. AR causes LVAD-left ventricular (LV) recirculation, which makes it difficult to continue LVAD support. However, the hemodynamics and myocardial oxygen metabolism of LVAD support with AR have not been clarified, especially, how pump rotation speed influences them. An animal model of LVAD with AR was newly developed, and how pump rotation speed influences hemodynamics and myocardial oxygen metabolism was examined in acute animal experiments. Five goats (55 ± 9.3 kg) underwent centrifugal type LVAD, EVAHEART implantation. The AR model was established by placing a vena cava filter in the aortic valve. Hemodynamic values and the myocardial oxygen consumption, delivery, and oxygen extraction ratio (O2ER) were evaluated with changing pump rotation speeds with or without AR (AR+, AR-). AR+ was defined as Sellers classification 3 or greater. AR was successfully induced in five goats. Diastolic aortic pressure was significantly lower in AR+ than AR- (p = 0.026). Central venous pressure, mean left atrial pressure, and diastolic left ventricular pressure were significantly higher in AR+ than AR- (p = 0.010, 0.047, and 0.0083, respectively). Although systemic flow did not improve with increasing pump rotation speed, LVAD pump flow increased over systemic flow in AR+, which meant increasing pump rotation speed increased LVAD-LV recirculation and did not contribute to effective systemic circulation. O2ER in AR- decreased with increasing pump rotation speed, but O2ER in AR+ was hard to decrease. The O2ER in AR+ correlated positively with the flow rate of LVAD-LV recirculation (p = 0.012). AR caused LVAD-LV recirculation that interfered with the cardiac assistance of LVAD support and made it ineffective to manage with high pump rotation speed.

Outcomes in children with advanced heart failure in Japan: importance of mechanical circulatory support.

The Japanese organ transplant law was revised in July 2010 in order to enable children aged <15 years to donate organs. However, the waiting time for orthotopic heart transplantation (HTx) is as long as 636 days in children due to a shortage of organ donors. Ventricular assist devices (VADs) have been widely used as a bridge to transplantation in Western countries, whereas experience with VADs is limited in Japan due to a lack of device availability for small children. This study aimed to clarify the clinical profiles and outcomes of children with advanced heart failure in Japan and to investigate the importance of mechanical circulatory support (MCS), VADs, and extracorporeal membrane oxygenation (ECMO) in children. A retrospective chart review of patients with advanced heart failure who were eligible for HTx between January 2006 and May 2015 was performed at the Department of Pediatric Cardiology, Tokyo Woman's Medical University, Japan. Patients were divided into two groups based on need for MCS. Clinical data pre- and post-revision of the Japanese organ transplant law were compared. Preoperative clinical conditions were evaluated based on Interagency Registry for Mechanically Circulatory Support (INTERMACS) profiles. Twenty-two patients were included in the study, 12 of whom required MCS. VADs were implanted in nine patients and ECMO was needed in seven patients. Of the MCS group, 5 deaths occurred in patients with a preoperative INTERMACS profile-1. High total bilirubin was found to be associated with mortality by multivariate logistic regression analysis (OR 7.8, p = 0.02). Wait list mortality was 32 % and no difference in clinical profiles pre- and post-revision of the Japanese organ transplant law was observed. Approximately 55 % of pediatric patients with advanced heart failure required MCS support. Preoperative conditions such as INTERMACS profile-1 and high total bilirubin were associated with poor outcomes. The Japanese organ transplant law revision had no significant influence on patient profiles or outcomes.

Circadian variation of motor current observed in fixed rotation speed continuous-flow left ventricular assist device support.

The algorithm for the physiological control provided by left ventricular assist devices (LVADs) has been controversial. In particular, little is known about the physiological control algorithm (such as for achieving physiological circadian rhythms) in continuous-flow LVADs. To investigate the existence of circadian variation, we retrospectively evaluated the LVAD flow-correlated motor current of patients supported by continuous-flow LVADs. The motor current and the pump speed were collected from the external controller every 10 min after device implantation, and the data were divided for every 30-day period, which began on midnight on the first post-operative day. The subjects were 18 patients (mean age 37.7, mean body surface area 1.71 m(2) at the time of operation) with dilated cardiomyopathy or dilated phase of hypertrophic cardiomyopathy. As of August 1, 2013, the patients' median support duration was 889 days. The mean calculated dominant period of motor current variation was 24.0 h and the mean amplitude was 11.7 mA for the entire duration. The amplitude of the motor current circadian variation tended to be increased until around the fifth month. The motor current had a tendency to be relatively low during the night time and high during the day time. A significant difference was found between the night-time and day-time mean motor current for the entire duration (p < 0.05). In conclusion, the circadian variation of the motor current could be observed over long term in patients with fixed rotation speed continuous-flow LVAD support.

Hemodynamic Evaluation of Asynchronous Speed Modulation of a Continuous-Flow Left Ventricular Assist Device in an Acute-Myocardial Injury Sheep Model.

Asynchronous rotational-speed modulation of a continuous-flow left ventricular assist device (LVAD) can increase pulsatility; however, the feasibility of hemodynamic modification by asynchronous modulation of an LVAD has not been sufficiently verified. We evaluated the acute effect of an asynchronous-modulation mode under LVAD support and the accumulated effect of 6 consecutive hours of driving by the asynchronous-modulation mode on hemodynamics, including both ventricles, in a coronary microembolization-induced acute-myocardial injury sheep model. We evaluated 5-min LVAD-support hemodynamics, including biventricular parameters, by switching modes from constant-speed to asynchronous-modulation in the same animals ("acute-effect evaluation under LVAD support"). To determine the accumulated effect of a certain driving period, we evaluated hemodynamics including biventricular parameters after weaning from 6-hour (6 h) LVAD support by constant-speed or asynchronous-modulation mode ("6h-effect evaluation"). The acute-effect evaluation under LVAD support revealed that, compared to the constant-speed mode, the asynchronous-modulation mode increased vascular pulsatility but did not have significantly different effects on hemodynamics, including both ventricles. The 6 h-effect evaluation revealed that the hemodynamics did not differ significantly between the two groups except for some biventricular parameters which did not indicate negative effects of the asynchronous-modulation mode on both ventricles. The asynchronous-modulation mode could be feasible to increase vascular pulsatility without causing negative effects on hemodynamics including both ventricles. Compared to the constant-speed mode, the asynchronous-modulation mode increased pulsatility during LVAD support without negative effects on hemodynamics including both ventricles in the acute phase. Six hours of LVAD support with the asynchronous-modulation mode exerted no negative effects on hemodynamics, including both ventricles, after weaning from the LVAD.

[Treatment of end-stage heart failure by implantable ventricular assist devices].

The strategy for severe heart failure treatment has changed dramatically since 2011 by the initiation of clinical use of implantable continuous flow ventricular assist devices( LVADs) in Japan. The continuous flow LVADs include DeBakey ventricular assist device (VAD), HeartMate II, HeartWare, Dura-Heart, and EVAHEART, although EVAHEART alone is clinically available in Japan currently. Hear-Mate II is the most popular LVAD with more than 10,000 worldwide implants, while its clinical result is superior to implantable pulsatile LVADs. Crucial complications with implantable LVADs include infection, aortic valve insufficiency, thromboembolism, bleeding, and right heart failure during circulatory support. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) has started in the United States, while Japanese Registry for Mechanically Assisted Circulatory Support(JMACS) initiated in Japan in 2010. These registries are essential for clinical evaluation of implantable LVADs as well as research and development in this field. The circulatory support with implantable LVADs is expected to be further contribution for the treatment of for end-stage heart failure patients.

Impact of anatomical position of the inflow cannula on stroke in patients with left ventricular assist devices.

OBJECTIVES: Stroke is a substantial complication of left ventricular assist device (LVAD) implantation. The relationship between stroke and the anatomical position of the inflow cannula of patients who underwent LVAD implantation was investigated. METHODS: We enrolled 15 patients with advanced-stage heart failure who underwent implantation of continuous-flow-LVAD. Data of patients who suffered a stroke within 6 months after LVAD implantation were retrospectively compared to those who remained free of stroke. The distance between the inflow duct and left ventricular (LV) septum (duct-sep distance) and its ratio to LV diastolic diameter (LVDd) were measured from echocardiography at 1 month after LVAD implantation. Receiver operating characteristic curves for the endpoint of stroke using the duct-sep distance to LVDd ratio was created and the cut-off value was calculated. The incidence of stroke during the 6 months after LVAD implantation according to this ratio was estimated using the Kaplan-Meier method. RESULTS: At 1 month after LVAD implantation, there were no significant differences in baseline characteristics and echocardiography parameters between the stroke and stroke-free groups. Receiver operating characteristic curve analysis for the endpoint of stroke using the duct-sep distance to LVDd ratio revealed 0.217 as a cut-off value (sensitivity: 80%, specificity: 80%, area under the curve: 0.72). Stroke was more frequent in patients with a duct-sep distance to LVDd ratio ⩾0.217 at 1 month than in those with a lower ratio. CONCLUSION: The duct-sep distance to LVDd ratio was associated with the occurrence of stroke, suggesting that inflow cannula position influences the incidence of stroke.

Neointima-inducing inflow cannula with titanium mesh for left ventricular assist device.

The formation of wedge thrombus is a crucial problem in any left ventricular assist device (LVAD) with a left ventricle apical inflow cannula. We therefore developed a new titanium mesh wrapped inflow cannula expecting to induce autologous neointima to avoid such wedge thrombus formation. We performed animal experiments to evaluate the feasibility of this newly developed inflow cannula with titanium mesh for the induction of autologous neointima. Four calves were implanted with the inflow cannula as well as an EVAHEART centrifugal pump LVAD (Sun Medical Technology Research Corp., Nagano, Japan) for a duration of about 2 months. The titanium mesh was enveloped with neointimal tissue grown from the ventricular endocardium. There was no thrombus formation in any of the blood pumps or around the outside of the inflow cannulas. The histological findings showed that the neointimal tissue consisted of a layer of endothelial cells and fibroblasts. The newly developed inflow cannula using a titanium mesh induces autologous neointima formation, avoiding wedge thrombus formation.

Bentall and redo-Konno Operation for an Adult With Aortic Paraprosthetic Leak and Root Aneurysm.

We report a case of Bentall and redo-Konno operation. A 39-year-old male with surgical history of Konno operation presented with hemolytic anemia and heart failure. Further evaluations revealed aortic paraprosthetic leak with moderate regurgitation, moderate biventricular outflow tract obstruction, and aortic root aneurysm. During the operation, the old Konno septoplasty patch with organized thrombus and the severely calcified right ventricular patch were replaced, and the aortic root was replaced with a larger mechanical valve in a Valsalva graft. Postoperative images showed appropriately reconstructed biventricular outflow tracts. The Bentall operation with redo-Konno was an excellent option in this situation.