Ring annuloplasty, optionally combined with edge-to-edge leaflet plications, should be amended with subvalvular repair techniques to efficaciously treat tricuspid regurgitation with severe tethering.

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.

A prospective randomized controlled study to assess the effectiveness of super FIXSORB WAVE® for sternal stabilization after sternotomy.

BACKGROUND: We developed a new sternal fixation device, Super FIXSORB WAVE®, a corrugated plate made of u-HA/PLLA, to improve sternal stability after sternotomy. This present study aimed to evaluate the new device clinically. METHODS: This prospective, single-blinded, multicenter trial randomized 69 patients to either wire cerclage only (group C, n = 30) or wire cerclage plus Super FIXSORB WAVE® (group W, n = 39). The primary endpoint was a degree of sternal displacement at six months. Displacement of the sternal halves in the anteroposterior and lateral directions was measured using computed tomography horizontal section images at the third costal and fourth intercostal levels. The secondary endpoints were sternal pain and quality-of-life over 6 months. RESULTS: Group W showed significantly reduced sternal anteroposterior displacement at both the third costal (0 [0-1.9] mm vs. 1.1 [0-2.1] mm; P = 0.014) and fourth intercostal (0 [0-1.0] mm) vs. 1.0 [0-1.8] mm; P = 0.015) levels than group C. In group W, lateral displacement was suppressed without a significant increase from 2 weeks to 6 months, while it increased in group C. There was no significant difference in postoperative sternal pain and quality-of-life between the two groups. No adverse events, such as infection, inflammation, or foreign body reaction, were observed with this device. CONCLUSIONS: Using Super FIXSORB WAVE®, sternal displacement was significantly suppressed in both the anteroposterior and lateral directions. The use of this device results in safe and easy sternal reinforcement without any adverse events, and sternal healing can be accelerated. CLINICAL TRIAL REGISTRY NUMBER: This study was registered in the Japan Registry of Clinical Trials (February 21, 2019; jRCTs032180146).

Prevention of thrombus formation in blood pump by mechanical circular orbital excitation of impeller in magnetically levitated centrifugal pump.

BACKGROUND: Mechanical circulatory support devices, such as left ventricular assist devices, have recently been used in patients with heart failure as destination therapy but the formation of thrombus in blood pumps remains a critical problem. In this study, we propose a mechanical antithrombogenic method by impeller excitation using a magnetically levitated (Maglev) centrifugal pump. Previous studies have shown that one-directional excitation prevents thrombus; however, it is effective in only one direction. In this study, we aimed to obtain a better effect by vibrating it in a circular orbit to induce uniform changes in the shear-rate field entirely around the impeller. METHODS: The blood coagulation time was compared using porcine blood. (1) The flow rate was set to 1 L/min, and applied excitation was at a frequency of 280 Hz and amplitude of 3 µm. (2) Moreover, the effect was compared by varying the frequency, amplitude, and direction of the excitation. In this experiment, the flow rate was set to 0.3 L/min. RESULTS: (1) The thrombus formation time was 77 min without excitation and 133 min with excitation, which was 1.7 times longer. (2) The results showed no difference between (280 Hz, 3 µm) and (50 Hz, 16 µm) circular orbital excitations, and no directional difference, with thrombus formation of 2.5 times longer under all conditions than that without excitation. CONCLUSION: In the case of simple reciprocating excitation, the time was approximately 1.2 times longer. This indicated that the circular orbital excitation is more effective.

Surgical extraction of cardiac implantable electronic device leads based on a heart team approach.

BACKGROUND: As cardiac implantable electronic devices, such as pacemakers, cardioverter defibrillators, and cardiac resynchronization therapies, have become more popular, device extraction has become more frequent. At our institution, individual treatment strategies are discussed at a heart team meeting. Transvenous lead extraction (TVLE) is a first-line treatment; however, surgical lead extraction (SLE) is sometimes selected as a primary choice to provide optimal treatment and maintain the medical safety policy. This study aimed to investigate the validity of this heart team decision-making. METHODS: From 2013 to 2021, 384 consecutive patients underwent lead extraction at our institution. RESULTS: SLE was proposed as the primary intervention for 21 patients who had high risk of bleeding, difficult TVLE conditions, large vegetations, and other concomitant cardiac diseases. Of the 363 TVLE patients, 10 patients required surgical intervention; 5 had TVLE difficulty followed by SLE and 5 had excessive bleeding. SLE was performed in 26 patients, 19 of whom required valve surgery, and 8 required plication of the great veins. In 4 of the 17 hybrid procedures with SLE and TVLE, excessive bleeding occurred due to laceration of the superior vena cava and innominate vein. Operative mortality was not observed in SLE patients but was observed in 1 of the 4 TVLE patients who required emergent open-chest hemostasis. CONCLUSIONS: The heart team discussion was essential to provide optimal treatment and maintain medical safety policies for each patient. SLE should be selected for patients with high risk of TVLE or other cardiac complications such as tricuspid valve incompetence.

Innovative experimental animal models for real-time comparison of antithrombogenicity between two oxygenators using dual extracorporeal circulation circuits and indocyanine green fluorescence imaging.

BACKGROUND: Antithrombogenicity of extracorporeal membrane oxygenation (ECMO) devices, particularly oxygenators, is a current problem, with numerous studies and developments underway. However, there has been limited progress in developing methods to accurately compare the antithrombogenicity of oxygenators. Animal experiments are commonly conducted to evaluate the antithrombogenicity of devices; however, it is challenging to maintain a steady experimental environment. We propose an innovative experimental animal model to evaluate different devices in a constant experimental environment in real-time. METHODS: This model uses two venous-arterial ECMO circuits attached to one animal (one by jugular vein and carotid artery, one by femoral vein and artery) and real-time assessment of thrombus formation in the oxygenator by indocyanine green (ICG) fluorescence imaging. Comparison studies were conducted using three pigs: one to compare different oxygenators (MERA vs. CAPIOX) (Case 1), and two to compare antithrombotic properties of the oxygenator (QUADROX) when used under different hydrodynamic conditions (continuous flow vs. pulsatile flow) (Cases 2 and 3). RESULTS: Thrombi, visualized using ICG imaging, appeared as black dots on a white background in each oxygenator. In Case 1, differences in the site of thrombus formation and rate of thrombus growth were observed in real-time in two oxygenators. In Case 2 and 3, the thrombus region was smaller in pulsatile than in continuous conditions. CONCLUSIONS: We devised an innovative experimental animal model for comparison of antithrombogenicity in ECMO circuits. This model enabled simultaneous evaluation of two different ECMO circuits under the same biological conditions and reduced the number of sacrificed experimental animals.

Long-term outcomes of papillary muscle relocation anteriorly for functional mitral regurgitation.

OBJECTIVES: This study aimed to evaluate the outcomes of the patients who underwent restrictive annuloplasty (RA) plus papillary muscle relocation anteriorly (PMR-A) with the risk factors in mitral valve repair for functional mitral regurgitation (FMR). METHODS: Eighty-six patients underwent mitral valve repair with RA for FMR. Thirty-five of them received additional bilateral papillary muscle relocation for severe leaflet tethering. The papillary muscles were relocated posteriorly (PMR-P) early in the study. Then, in the later period, the technique was modified to PMR-A, in which the papillary muscles were relocated anteriorly for 24 cases. The survival of the patients undergoing RA + PMR-A was examined retrospectively, adjusting for differences in patient background. RESULTS: Twenty-three deaths were observed during the follow-up period out of the 86 cases. Independent preoperative risk factors for survival were left ventricular ejection fraction, patient age and B-type natriuretic peptide (BNP) level. Among the patients with BNP <1000 pg/ml, 5-year survival after RA plus PMR-A was 84.7%, while RA alone was 78.6% and RA + PMR-P 57.1%. Cox proportional hazards regression adjusted for the preoperative risk factors showed a significantly higher hazard ratio of RA + PMR-P to RA + PMR-A (12.77, P = 0.011), while the hazard ratio of RA alone to RA + PMR-A was not significantly different. Furthermore, reverse remodelling of the left ventricle was observed for 3 years only in RA + PMR-A. CONCLUSIONS: Long-term survival for patients who underwent RA plus bilateral PMR-A was promising. Patients with significantly higher BNP had lower survival after valve repair for FMR.

Efficacy of singular and composite annular repositioning and subvalvular surgical techniques to treat functional tricuspid regurgitation due to leaflet tethering: Early results of a feasibility study.

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.

The rotational position of the aortic valve: implications for valve-sparing aortic root replacement.

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.

Mid-term results of mitral valve reconstruction with autologous pericardial patch for active infective endocarditis with extensive leaflet destruction.

OBJECTIVES: This study aimed to evaluate the outcomes of our repair technique using autologous pericardial patches for active infective endocarditis with extensive mitral valve destruction. METHODS: From 2009 through 2016, 12 patients with extensive mitral leaflet destruction due to infective endocarditis underwent mitral valve repair with an autologous pericardial patch. Mid-term clinical outcomes and echocardiographic findings of these patients were retrospectively assessed. RESULTS: The perioperative mortality rate was 8.3% (1/12). Postoperatively, the mitral regurgitation grade was ≤ 1 + in all patients. During 5.0 ± 3.2 years of follow-up, there was no recurrence of infective endocarditis or death. There were no cases of mitral regurgitation grade > + 1 and pressure gradient > 5 mmHg during follow-up among 6 patients who underwent posterior leaflet reconstruction, whereas elevation of the pressure gradient was observed in patients who underwent reconstruction of two areas of the anterior leaflet and survived up till the follow-up phase among 3 patients who underwent anterior leaflet repair. The mitral regurgitation grade worsened and pressure gradient was elevated during the follow-up phase in the 2 patients who underwent bi-leaflet repair, and reoperation was performed. CONCLUSION: Mitral valve reconstruction using autologous pericardial patch is a useful treatment option for extensive mitral valve destruction due to active infective endocarditis. Our clinical data revealed that good mid-term results were obtained for posterior leaflet lesions, while extensive anterior leaflet and bi-leaflet lesion repair did not yield satisfactory results. The indication for surgical repair should be carefully evaluated when an extensive anterior region is involved.

Surgical strategy for inflammatory thoracic aortic aneurysms in the endovascular surgery era.

OBJECTIVE: Inflammatory thoracic aortic aneurysms (TAAs) are very rare aortic conditions. Resection and replacement of the inflammatory aorta is the first-line treatment, and thoracic endovascular aortic repair (TEVAR) has recently been reported as a less invasive alternative even for this aortic cohort. In the present study, we reviewed our experience with inflammatory TAAs and assessed the preoperative management, surgical procedures, and outcomes. METHODS: From 2006 to 2019, 21 surgeries were performed for inflammatory TAAs in 17 of 2583 patients (0.7%) who had undergone cardiovascular surgery at our institution. The etiologies were Takayasu's arteritis in 13 patients, giant cell arteritis in 2, antineutrophil cytoplasmic antibody-associated vasculitis in 1, and unknown in 1. The mean follow-up period was 66.2 ± 50.2 months (range, 19-186 months). RESULTS: Three patients had undergone multiple surgeries. The aorta was replaced in 14 patients (ascending aorta in 9, aortic arch in 4, and thoracoabdominal aorta in 1). Three isolated TEVARs were performed in two patients and single-stage hybrid aortic repair (ascending aorta and partial arch replacement combined with zone 0 TEVAR) in four patients for extended arch and descending thoracic aortic aneurysms. Stent grafts were deployed on the native aorta in five of the seven TEVARs. The perioperative inflammation was well-controlled with prednisolone (mean dose, 7.4 ± 9.4 mg) in all patients except for one who had required two surgeries under inflammation-uncontrolled situations. No aorta-related complications, including anastomotic aneurysms and TEVAR-related aortic dissection, developed during the follow-up period, and the 5-year freedom from all-cause death was 92.9%. CONCLUSIONS: The mid-term outcomes of surgery for inflammatory TAAs were acceptable. Although replacement remains the standard procedure for inflammatory TAAs, TEVAR is a less invasive acceptable alternative when the inflammation is properly managed.

One-Stage Hybrid Total Aortic Arch and Descending Thoracic Aortic Repair is a Safe and Secure Procedure With Less Postoperative Complications for Extended Aortic Arch Aneurysms.

PURPOSE: Hybrid aortic arch repair (HAR) has been implemented for extended aortic arch and descending thoracic aortic disease since 2012 in our institution. This study aimed to estimate the early and mid-term efficacy and safety of HAR. MATERIALS AND METHODS: From 2007 to 2019, 56 patients underwent HAR for extended aortic arch disease, and 75 patients underwent total arch replacement (TAR) for arch-limited disease. HAR comprises 3 procedures: replacement of the aorta, reconstruction of all arch vessels, and thoracic endovascular aortic repair (TEVAR) from zone 0 to the descending aorta after cardiopulmonary bypass is off in 1 stage. The type II-1 HAR procedure, in which the ascending aorta and aortic arch distal to the brachiocephalic artery are replaced, was the most frequently selected procedure (40/56 patients). The outcomes of the type II-1 HAR procedure were compared with those of TAR using the Cox regression analysis. RESULTS: The median follow-up period was 36 months. In HAR, the operative mortality, in-hospital mortality, and postoperative permanent neurological deficits were not observed. The paraplegia rate was 1.8%. TEVAR-related complications occurred in 3 patients. Among the patients with non-ruptured atherosclerotic aortic arch aneurysm (31 type II-1 HAR patients and 36 TAR patients, the postoperative respiratory support time in those who underwent type II-1 HAR was quicker than in those who underwent TAR (p<0.01). The rate of 6 year freedom from all-cause death in type II-1 HAR (83.1%) was numerically higher than that in TAR (74.7%), and the rate of 6 year freedom from surgery-related complications in type II-1 HAR (90.3%) was numerically lower than that in TAR (96.9%) due to the occurrence of TEVAR-related complications, and the rate of 6 year freedom from reintervention to the descending thoracic aorta in type II-1 HAR (100%) seemed to be better than that in TAR (83.7%). However, Cox regression analysis did not reveal any statistical difference between the 2 procedures. CONCLUSIONS: HAR, especially the type II-1 procedure, can treat extended aortic arch disease with acceptable survival outcomes. The development of TEVAR technology will further improve the outcomes of HAR in the future.

Novel application of indocyanine green fluorescence imaging for real-time detection of thrombus in a membrane oxygenator.

Extracorporeal membrane oxygenation (ECMO) plays an important role in the coronavirus disease 2019 (COVID-19) pandemic. Management of thrombi in ECMO is generally an important issue; especially in ECMO for COVID-19 patients who are prone to thrombus formation, the thrombus formation in oxygenators is an unresolved issue, and it is very difficult to deal with. To prevent thromboembolic complications, it is necessary to develop a method for early thrombus detection. We developed a novel method for detailed real-time observation of thrombi formed in oxygenators using indocyanine green (ICG) fluorescence imaging. The purpose of this study was to verify the efficacy of this novel method through animal experiments. The experiments were performed three times using three pigs equipped with veno-arterial ECMO comprising a centrifugal pump (CAPIOX SL) and an oxygenator (QUADROX). To create thrombogenic conditions, the pump flow rate was set at 1 L/min without anticoagulation. The diluted ICG (0.025 mg/mL) was intravenously administered at a dose of 10 mL once an hour. A single dose of ICG was 0.25mg. The oxygenator was observed with both an optical detector (PDE-neo) and the naked eye every hour after measurement initiation for a total of 8 hours. With this dose of ICG, we could observe it by fluorescence imaging for about 15 minutes. Under ICG imaging, the inside of the oxygenator was observed as a white area. A black dot suspected to be the thrombus appeared 6-8 hours after measurement initiation. The thrombus and the black dot on ICG imaging were finely matched in terms of morphology. Thus, we succeeded in real-time thrombus detection in an oxygenator using ICG imaging. The combined use of ICG imaging and conventional routine screening tests could compensate for each other's weaknesses and significantly improve the safety of ECMO.

Efficacy of multidisciplinary team approach with extracorporeal membrane oxygenation for COVID-19 in a low volume ECMO center.

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.

Evaluation of real-time thrombus detection method in a magnetically levitated centrifugal blood pump using a porcine left ventricular assist circulation model.

Pump thrombosis induces significant complications and requires timely detection. We proposed real-time monitoring of pump thrombus in a magnetically levitated centrifugal blood pump (mag-lev pump) without using additional sensors, by focusing on the changes in the displacement of the pump impeller. The phase difference between the current and displacement of the impeller increases with pump thrombus. This thrombus detection method was previously evaluated through simulated circuit experiments using porcine blood. Evaluation of real-time thrombus detection in a mag-lev blood pump was performed using a porcine left ventricular assist circulation model in this study. Acute animal experiments were performed five times using five Japanese domestic pigs. To create thrombogenic conditions, fibrinogen coating that induces thrombus formation in a short time was applied to the inner surfaces of the pump. An inflow and an outflow cannula were inserted into the apex of the left ventricle and the carotid artery, respectively, by a minimally invasive surgical procedure that allowed minimal bleeding and hypothermia. Pump flow was maintained at 1 L/min without anticoagulation. The vibrational frequency of the impeller (70 Hz) and its vibrational amplitude (30 µm) were kept constant. The thrombus was detected based on the fact that the phase difference between the impeller displacement and input current to the magnetic bearing increases when a thrombus is formed inside a pump. The experiment was terminated when the phase difference increased by over 1° from the lowest value or when the phase difference was at the lowest value 12 hours after commencing measurements. The phase difference increased by over 1° in three cases. The pump was stopped after 12 hours in two cases. Pump thrombi were found in the pump in three cases in which the phase difference increased by over 1°. No pump thrombus was found in the other two cases in which the phase difference did not increase. We succeeded in real-time thrombus monitoring of a mag-lev pump in acute animal experiments.

A successful case of extracorporeal membrane oxygenation treatment for intractable pneumothorax in a patient with COVID-19.

BACKGROUND: Some patients with coronavirus disease 2019 (COVID-19) develop pneumothorax. Tube thoracotomy and bulla resection could generate aerosols and cause virus transmission; the optimal treatment strategy remains unclear. CASE PRESENTATION: A 57-year-old male was transferred as a severe COVID-19 pneumonia case. On the 16th day after admission, the patient's respiratory condition deteriorated, and the chest X-ray revealed the presence of severe right-sided pneumothorax. A chest drain was immediately inserted; however, a significant air leak continued, and severe ventilator settings were required. Thus, veno-venous extracorporeal membrane oxygenation (VV-ECMO) treatment was initiated to allow the lungs to rest. After 10 days of lung-protective ventilation, the patient was weaned from ECMO and the chest drain was removed on the following day with no major comorbidities. CONCLUSION: The combination of ECMO with lung rest strategy could be a treatment option for intractable pneumothorax with COVID-19 to avoid unnecessary surgical procedures and aerosol generation.

Suction-fixing surgical device for assisting liver manipulation with laparoscopic forceps.

PURPOSE: Noninvasiveness and stability are significant issues in laparoscopic liver resection. Inappropriate grasping force can cause damage or serious bleeding to the liver. In addition, instability of grasping can result unsafe operations or wavered cutting. We propose a surgical device to improve stability of liver manipulation. METHODS: A proposed device adheres to the liver surface with suction fixation, then tunes its stiffness to being hard and shapes like as a bulge on the liver surface to be grasped with laparoscopic forceps. It consists of two soft beams, a chamber sponge, membrane covering the device upper, suburb extrusion wing membrane, a vacuuming tube and to-be-grasped bars. The beams are designed as being non-stretchable and easy to bend. The device is connected to a medical vacuuming pump to vacuum air in the device and then gets hard to transfer forceps operation well. This stiffness tuning mechanism by pneumatic control features the device for achieving good liver shape followability and forceps operation propagation less invasively. The proposed device was tested with rubber phantoms and porcine livers on shape followability, stiffness transition, liver invasiveness and operational usability in the experiments. RESULTS: Performance of the proposed device was assessed in experiments. The device showed good object-shape followability. It held the liver with 2.43-N force for vertical lifting and 4.90-N shear force with - 80 kPa vacuuming pressure. Invasiveness was reduced to acceptable level of liver damage. In usability test, the device grasped the liver stably and transferred surgical forceps operations to the liver surface well. CONCLUSION: The proposed device showed effective performance to improve laparoscopic liver manipulation. It held the liver stably and less invasively and transferred forceps operation force to the liver surface well.

Development of a Novel Heart Positioner for Minimally Invasive Coronary Surgery.

PURPOSE: We developed a heart positioner, the Tentacles NEO, specifically designed for minimally invasive coronary artery bypass grafting (MICS-CABG). DESCRIPTION: The device has 3 flexible suction tubes, with a suction cup at the tip of each tube. The suction tubes can be detached from the device body, allowing them to be manipulated in any direction through a small incision around the small thoracotomy. When the device displaces the heart, the suction cup moves behind the chest wall and does not crowd the operative field. EVALUATION: Although the sideways suction force of the new device was as strong as that of the original device, Tentacles, the longitudinal and perpendicular force exerted was approximately 80% of the original device. Nevertheless, the new device could safely and favorably displace the heart in a pig model and even during off-pump CABG via sternotomy. During MICS-CABG, the device was able to displace the heart without crowding the operative field. CONCLUSIONS: The new heart positioner, Tentacles NEO, is a useful and practical heart positioner suitable for MICS-CABG.

Verification of a thrombus induction method at the target point inside the blood pump using a fibrinogen coating for a thrombus detection study.

Although the magnetically levitated centrifugal blood pump (mag-lev pump) is considered superior to other pumps in antithrombogenicity, thrombotic complications are still reported. Research into thrombus detection inside a mag-lev pump is very important for solving this problem. Our research group has already proposed a method to detect a thrombus inside a mag-lev pump in real time without an additional sensor, which is named the impeller vibration method. To efficiently advance our research with reproducibility, a preconditioning method to induce thrombus inside the pump was thought to be necessary. Therefore, this study aimed to develop a preconditioning method that induces thrombus formation. To verify this method, in vitro experiments for thrombus detection were performed. A mag-lev pump developed at Tokyo Institute of Technology was used. A fibrinogen solution was coated on the inner surfaces of the bottom housing to induce thrombus formation at the target point inside the pump. The thrombus is detected by utilizing the phenomenon that the phase difference between the impeller displacement and input current to the magnetic bearing increases when a thrombus is formed inside a pump. Five hundred mL of porcine blood anticoagulated with heparin sodium was circulated in the mock circuit, and protamine sulfate was administered. Flow rate (1 L/min), impeller vibrational frequency (70 Hz), and vibrational amplitude (30 µm) were set to constant. The experiment was terminated when the phase difference increased by over 2° from the minimum value. The experiments were performed in fibrinogen-coated (group F, n = 5) and non-coated pumps (group N, n = 5). In group F, thrombus formation was observed at the fibrinogen-coated point of the housing. In contrast, a relatively small thrombus was observed in varying locations such as the housing or the impeller in group N. Thrombus formation time (the time from when the phase difference takes the minimum value to when the experiment is terminated) was different between the two groups. The mean time was significantly shorter in group F (44 ± 29 minutes) than in group N (143 ± 38 minutes; p = 0.0019). Therefore, a preconditioning method that induced thrombus formation at the target point inside a blood pump was successfully developed.

Coronary Ostial Patch Angioplasty With Femoral Artery in Takayasu Arteritis.

Takayasu arteritis (TA) occasionally involves the coronary ostium leading to myocardial ischemia. Although surgical coronary ostial angioplasty is desirable for ostial stenosis, the patch materials and long-term results are controversial. We used femoral artery (FA) as a patch material for coronary ostial angioplasty in 3 TA patients. Coronary ostial enlargement with a longitudinal incision followed by rectangular FA patch augmentation was performed to extend the narrowing coronary ostium. In all patients, coronary ostial stenosis was successfully repaired. Ostial angioplasty using an FA patch would be a reasonable surgical strategy to treat coronary ostial stenosis in TA.

Safe and Effective Ultrasound-guided Myectomy and Mitral Valve Repair for HCM.

Surgery for obstructive hypertrophic cardiomyopathy with mitral abnormality requires a combined procedure of myectomy and mitral leaflet plication for relieving mitral systolic anterior motion and left ventricular outflow tract obstruction. We report a combined procedure of myectomy using intracardiac high-resolution ultrasonography and mitral bileaflet shortening in obstructive hypertrophic cardiomyopathy. Stepwise real-time verification of residual ventricular mass using high-resolution ultrasonic probe would be a potent addition to our armamentarium. This modality provides safe and effective myectomy, which has been a most technically challenging surgical procedure especially for inexperienced surgeons.