Mild Systemic Hypothermic Circulatory Arrest Using a Frozen Elephant Trunk Graft with Endo-Balloon Occlusion for Total Arch Replacement.

BACKGROUND: Stroke and paraplegia are serious complications of total aortic arch replacement (TAR). Hypothermic circulatory arrest and cerebral perfusion reduce the risk of neurologic complications, but longer circulatory arrest time remains a risk factor for such complications. We utilized a frozen elephant trunk (FET) with endo-balloon occlusion under mild systemic hypothermia, which allowed us to shorten circulatory arrest time. METHODS: Between April 2007 and May 2020, 72 patients underwent elective TAR using antegrade cerebral perfusion (ACP). They were divided into 2 groups. 64 patients received conventional TAR with moderate systemic hypothermic (bladder temperature, 25-28°C) circulatory arrest (group C). We used a FET with endo-balloon occlusion and retrograde perfusion through the femoral artery for the newest 8 patients who had mild hypothermic (bladder temperature of 30°C) circulatory arrest (group B). RESULTS: The mean operation time (257.5 ± 42.1 versus 327.8 ± 84.9 min, P = .023), CPB time (144.4 ± 28.1 versus 178.2 ± 26.4 min, P = .003), cardiac arrest time (75.5 ± 21.2 versus 95.7 ± 56.4 min, P < .001), SCP time (100.8 ± 25.5 versus 124 ± 23.2 min, P < .001), lower body circulation arrest time (17.2 ± 4.2 versus 62.5 ± 19.3 min, P < .001) were significantly shorter in the endo-balloon occlusion group. There were no perioperative neurological and renal complications or mortality in FET group. The new technique enabled a decrease in mechanical ventilation time (8.6 ± 1.4 versus 13.9 ± 5.7 min, P = .015) and hospital length of stay (9.7 ± 1.8 versus 18.3 ± 4.6 min, P = .005). CONCLUSION: FET using an endo-balloon occlusion with mild hypothermia is a safe and an effective approach in TAR.

A CAD-CAM approach for designing and fabricating a periodontal prosthesis: A clinical report.

The periodontal prosthesis is a successful retrievable fixed restoration provided for patients with a periodontally involved dentition who lack alternative fixed options. However, its popularity has declined due to the introduction of dental implants, as well as the cost and complexity of fabrication. Nonetheless, this remains a viable option for patients who cannot undergo implant surgery. This clinical report describes the use of computer-aided design and computer-aided manufacturing (CAD-CAM) technology to streamline the fabrication of a periodontal prosthesis.

High-Pressure Polymorphs of LaHO with Anion Coordination Reversal.

Two novel high-pressure polymorphs of lanthanum oxyhydride have been successfully predicted and stabilized under pressure. When reacted at 3 GPa, the fluorite structure of LaHO with anion-centered tetrahedral (HLa4/OLa4) geometry is transformed to the PbCl2-type structure involving coordination number increase of H- to five (HLa5 square pyramids). Upon further application of pressure to 5 GPa, LaHO changed into the anti Fe2P-type structure. Interestingly, the 5 GPa phase contains tetrahedral HLa4 and square-pyramidal OLa5 geometry, meaning coordination switching, as confirmed by ab initio calculations. The structural analysis shows that this unprecedented phenomenon is enabled by higher compressibility of hydride anion and emphasizes its potential in the search for new high-pressure forms of hydride-based mixed anion materials.

Pressure-Stabilized Cubic Perovskite Oxyhydride BaScO2H.

We report a scandium oxyhydride BaScO2H prepared by solid state reaction under high pressure. Rietveld refinements against powder synchrotron X-ray and neutron diffraction data revealed that BaScO2H adopts the ideal cubic perovskite structure (Pm3̅m), where oxide (O2-) and hydride (H-) anions are disordered. 1H nuclear magnetic resonance (NMR) spectroscopy provides a positive chemical shift of about +4.4 ppm, which can be understood by the distance to the nearest (and possibly the next nearest) cation from the H nucleus. A further analysis of the NMR data and calculations based on ab initio random structure searches suggest a partial cis preference in ScO4H2 octahedra. The present oxyhydride, if compositionally or structurally tuned, may become a candidate for H- conductors.

High-Pressure Synthesis of Fully Occupied Tetragonal and Cubic Tungsten Bronze Oxides.

A high-pressure reaction yielded the fully occupied tetragonal tungsten bronze K3 W5 O15 (K0.6 WO3 ). The terminal phase shows an unusual transport property featuring slightly negative temperature-dependence in resistivity (dρ/dT<0) and a large Wilson ratio of RW =3.2. Such anomalous metallic behavior possibly arises from the low-dimensional electronic structure with a van Hove singularity at the Fermi level and/or from enhanced magnetic fluctuations by geometrical frustration of the tungsten sublattice. The asymmetric nature of the tetragonal tungsten bronze Kx WO3 -K0.6-y Bay WO3 phase diagram implies that superconductivity for x≤0.45 originates from the lattice instability because of potassium deficiency. A cubic perovskite KWO3 phase was also identified as a line phase-in marked contrast to Nax WO3 and Lix WO3 with varying quantities of x (<1). This study presents a versatile method by which the solubility limit of tungsten bronze oxides can be extended.

Glass Formation of a Coordination Polymer Crystal for Enhanced Proton Conductivity and Material Flexibility.

The glassy state of a two-dimensional (2D) Cd(2+) coordination polymer crystal was prepared by a solvent-free mechanical milling process. The glassy state retains the 2D structure of the crystalline material, albeit with significant distortion, as characterized by synchrotron X-ray analyses and solid-state multinuclear NMR spectroscopy. It transforms to its original crystal structure upon heating. Thus, reversible crystal-to-glass transformation is possible using our new processes. The glass state displays superior properties compared to the crystalline state; specifically, it shows anhydrous proton conductivity and a dielectric constant two orders of magnitude greater than the crystalline material. It also shows material flexibility and transparency.

MnTaO2N: polar LiNbO3-type oxynitride with a helical spin order.

The synthesis, structure, and magnetic properties of a polar and magnetic oxynitride MnTaO2N are reported. High-pressure synthesis at 6 GPa and 1400 °C allows for the stabilization of a high-density structure containing middle-to-late transition metals. Synchrotron X-ray and neutron diffraction studies revealed that MnTaO2N adopts the LiNbO3-type structure, with a random distribution of O(2-) and N(3-) anions. MnTaO2N with an "orbital-inactive" Mn(2+) ion (d(5); S=5/2) exhibits a nontrivial helical spin order at 25 K with a propagation vector of [0,0,δ] (δ≈0.3), which is different from the conventional G-type order observed in other orbital-inactive perovskite oxides and LiNbO3-type oxides. This result suggests the presence of strong frustration because of the heavily tilted MnO4N2 octahedral network combined with the mixed O(2-)/N(3-) species that results in a distribution of (super)-superexchange interactions.

[Excision of a left atrial myxoma through right minithoracotomy in a patient with multiple myeloma; report of a case].

We present a case of a 63-year-old female who underwent an excision of a left atrial myxoma. Previously, she had been diagnosed with multiple myelomas and received radiation therapy and chemotherapy. A left atrial myxoma was found at an annual medical check-up. The myxoma was removed via a right minithoracotomy with peripheral cannulation to minimize bleeding complications and surgical site infection. She was transferred to the referring hospital on postoperative day 7 due to recurrence of multiple myelomas. She was doing well 14 months after the operation. Right minithoracotomy is a useful approach to minimizing the risks of bleeding and infection in patients with multiple myelomas.

Direct synthesis of chromium perovskite oxyhydride with a high magnetic-transition temperature.

We report a novel oxyhydride SrCrO2H directly synthesized by a high-pressure high-temperature method. Powder neutron and synchrotron X-ray diffraction revealed that this compound adopts the ideal cubic perovskite structure (Pm3̄m) with O(2-)/H(-) disorder. Surprisingly, despite the non-bonding nature between Cr 3d t(2g) orbitals and the H 1s orbital, it exhibits G-type spin ordering at T(N)≈380 K, which is higher than that of RCrO3 (R=rare earth) and any chromium oxides. The enhanced T(N) in SrCrO2H with four Cr-O-Cr bonds in comparison with RCr(3+)O3 with six Cr-O-Cr bonds is reasonably explained by the tolerance factor. The present result offers an effective strategy to tune octahedral tilting in perovskites and to improve physical and chemical properties through mixed anion chemistry.

Strategy for acute DeBakey type I aortic dissection considering midterm results: a retrospective cohort study comparing ascending aortic replacement and total arch replacement with frozen elephant trunk technique.

BACKGROUND: Acute type A aortic dissection is treated with an emergency procedure that uses ascending aortic replacement (AAR). However, to avoid a residual dissected aorta with a false lumen, total arch replacement (TAR) is required. The frozen elephant trunk (FET) technique is a promising surgical approach that promotes false lumen obliteration in a single step. Therefore, this retrospective single-center study aimed to evaluate the operative outcomes of AAR and TAR with FET. METHODS: Between 2007 and 2021, 143 patients with acute DeBakey type I aortic dissection underwent a central repair using AAR (n = 95) or TAR with FET (n = 43). All perioperative variables, the duration of all-cause mortality, and aortic events defined as dilatation of the distal aorta > 5 cm, new occurrences of aortic dissection, distal aortic surgery, and distal aortic rupture were recorded. We compared these perioperative variables and mid-term results with an additional focus on distal aortic events. RESULTS: Patient background data did not differ between the two groups. Perioperative results for the TAR with FET group vs the AAR group showed similar operative times (306 vs 298 min, P = 0.862), but the TAR group had longer cardiopulmonary bypass times (154 vs 179 min, P < 0.001). The freedom from all-cause death for the TAR vs AAR groups using the Kaplan-Meier method was 81.9% vs 85.4% and 78.0% vs 85.4% (P = 0.407) at 1 and 3 years, respectively. Freedom from aorta-related events was 90.6% vs 97.6% and 69.3% vs 87.0% (P = 0.034) at 1 and 3 years, respectively. CONCLUSIONS: TAR with FET had comparable perioperative results to AAR in acute DeBakey type I aortic dissection and was considered a valuable method to avoid aorta-related events in the midterm.

Thoracic Endovascular Aortic Repair Without Subclavian Revascularization of a Ruptured Kommerell Diverticulum.

A ruptured Kommerell diverticulum is extremely rare. This is the first report of thoracic endovascular aortic repair without subclavian revascularization of a ruptured Kommerell diverticulum with a right-sided aortic arch. However, decisions regarding subclavian revascularization should be individualized based on the patient's anatomy and clinical presentation.

[Can local administration of tranexamic acid reduce aspirin-induced bleeding in off-pump coronary artery bypass grafting( CABG) ?].

OBJECTIVES: We examined the effect of local administration of tranexamic acid( TA) on reducing aspirin-induced bleeding in off-pump coronary artery bypass grafting(CABG). METHODS: From July 2009 to January 2011, 88 cases with off-pump CABG were divided into 4 groups:group C including 19 cases without preoperative aspirin or local administration of TA, group A including 23 cases with preoperative aspirin alone, group T including 19 cases with local administration of TA alone, and group AT including 27 cases with both preoperative aspirin and local administration of TA. RESULTS: The bleeding volume after 24 hours in group A was significantly larger than that in group C(p=0.0085). The bleeding volume in group AT was significantly smaller than that in group A (p<0.0001), and the bleeding volume in group T was also significantly smaller than that in group C (p=0.0054). There was no significant difference between group T and AT. CONCLUSIONS: The use of local administration of tranexamic acid indicated the reduction of postoperative bleeding even in patients with preoperative aspirin use.

Concomitant surgery of minimally invasive direct coronary artery bypass with left atrium appendage closure.

Surgical approaches of minimally invasive direct coronary artery bypass and left atrial appendage exclusion are different, and issues may arise in cases of concomitant surgery. Moreover, the safety of concomitant procedures has not been established. A man in his 80s with a history of stroke required minimally invasive coronary artery bypass grafting and left atrial appendage closure for the stenosis of the left anterior descending artery and atrial fibrillation. He suffered from bladder bleeding, which required early reduction of anticoagulant and antiplatelet medication. Therefore, he wished for surgical treatment. A lateral incision was necessary for left atrial appendage closure in minimally invasive surgery. We performed totally endoscopic harvest of the internal thoracic artery without a robotic system. This method allowed the incision to be made more laterally. Combining the endoscopic harvest of the internal mammary artery with left atrial appendage closure via lateral incision may be a reasonable technique.

Case report: Unruptured small middle cerebral artery aneurysm with perianeurysmal edema.

Background: Perianeurysmal edema (PAE) has a tendency to occur in embolized aneurysms but also in partially thrombosed, large, or giant aneurysms. However, there are only a few cases recorded in which PAE was detected in untreated or small aneurysms. We suspected that PAE might be an impending sign of aneurysm rupture in these cases. Herein, we presented a unique case of PAE that was related to an unruptured small middle cerebral artery aneurysm. Case description: A 61-year-old woman was referred to our institute due to a newly formed abnormal fluid-attenuated inversion recovery (FLAIR) hyperintense lesion in the right medial temporal cortex. Upon admission, the patient did not present with any symptoms or complaints; however, FLAIR and CT angiography (CTA) suggested an increased risk of aneurysm rupture. Aneurysm clipping was conducted, and no evidence of subarachnoid hemorrhage and hemosiderin deposits around the aneurysm and brain parenchyma was noted. The patient was discharged home without any neurological symptoms. MRI taken at eight months post-clipping revealed complete regression of the FLAIR hyperintense lesion around the aneurysm. Conclusion: PAE in unruptured, small aneurysm is thought to be an impending sign of aneurysm rupture. Early surgical intervention is critical even for small aneurysms with PAE.

Facile formation of barium titanium oxyhydride on a titanium hydride surface as an ammonia synthesis catalyst.

Oxyhydrides are promising compounds as supports for ammonia synthesis catalysts because they suppress hydrogen poisoning on the catalyst surface and enhance the ammonia synthesis activity. Herein, we developed a facile method for preparing BaTiO2.5H0.5, a perovskite oxyhydride, on a TiH2 surface via the conventional wet impregnation method using TiH2 and Ba hydroxide. Scanning electron microscopy and high-angle annular dark-field scanning transmission electron microscopy observations revealed that BaTiO2.5H0.5 crystallized as nanoparticles of ca. 100-200 nm on the TiH2 surface. The Ru-loaded catalyst Ru/BaTiO2.5H0.5-TiH2 exhibited 2.46 times higher ammonia synthesis activity (3.05 mmol-NH3 g-1 h-1 at 400 °C) than the benchmark Ru catalyst Ru-Cs/MgO (1.24 mmol-NH3 g-1 h-1 at 400 °C) because of the suppression of hydrogen poisoning. The analysis of reaction orders showed that the effect of suppressing hydrogen poisoning on Ru/BaTiO2.5H0.5-TiH2 was equivalent to that of the reported Ru/BaTiO2.5H0.5 catalyst, thus supporting the formation of BaTiO2.5H0.5 perovskite oxyhydride. This study demonstrated that the selection of appropriate raw materials facilitates the formation of BaTiO2.5H0.5 oxyhydride nanoparticles on the TiH2 surface using the conventional synthesis method.

[Efforts to achieve anastomosis forms in coronary artery bypass grafting; cuff-like and skirt-like anastomoses].

As the type of anastomotic site is considered to be one of the decisive factors for graft-patency in coronary artery bypass grafting(CABG),our aim is to achieve anastomosis forms that potentially promote long-term graft-patency rates. When an arterial graft is used, side-to-side anastomosis is performed, with its incision length being longer than that of the coronary artery, to achieve a cuff-like anastomosis form. When a vein graft is used, on the other hand, it is incised shorter than the coronary artery to achieve a skirt-like anastomosis form instead of a purse-like one. It is thus expected that reliable anastomosis forms can be observed in postoperative angiography.

Combination of endoscopic internal thoracic artery harvest and proximal anastomoses on the descending aorta in minimally invasive coronary artery bypass grafting.

Minimally invasive coronary artery bypass grafting is less invasive. Proximal anastomoses at the ascending aorta, in contrast, are technically difficult to perform because of the limited field of view. A man in his 60s undergoing haemodialysis required minimally invasive coronary artery bypass grafting for left anterior descending artery and circumflex arterial restenosis. We successfully performed minimally invasive coronary artery bypass grafting with a proximal graft anastomosis of the descending aorta. A thoracotomy was performed to extend the lateral approach to the descending aorta. We performed a minithoracotomy using three-dimensional endoscopy for internal thoracic artery harvesting. Endoscopic internal thoracic artery harvesting minimises incision length. The combination of endoscopic and lateral thoracotomy incisions in minimally invasive coronary artery bypass grafting enabled small and lateral thoracotomy incisions.

Revascularization for controlling hypertension and improving cardiorenal failure in Leriche syndrome.

Leriche syndrome usually occurs when atherosclerotic obstructions result in luminal narrowing of the abdominal aorta or iliac arteries and leads to thrombosis; it rarely causes heart or renal failure. We report the case of a 58-year-old Asian man with heart and renal failure as the dominant clinical manifestations of renovascular hypertension caused by Leriche syndrome. We performed an aorto-bifemoral bypass and unilateral renal artery stenting. Post-operative echocardiography showed improved cardiac function, with the left ventricular ejection fraction increasing from 30% before surgery to 54.2% after surgery. Moreover, his heart rate and blood pressure became stable, and his serum creatinine and brain natriuretic peptide levels decreased from 3.46 to 1.08 mg/dL and 685 to 4 pg/mL, respectively. Our case report shows that aorto-bifemoral bypass and unilateral renal artery stenting can effectively treat heart and renal failure resulting from renovascular hypertension caused by Leriche syndrome.

Enhanced ammonia synthesis activity of Ru-supported cerium-lanthanum oxide induced by Ti substitution forming mesopores.

Ru/Ce0.5La0.5-xTixO1.75+0.5x solid solutions with cubic fluorite structure were successfully synthesized via the polymerized complex method. While the Ti substitution enhanced Ce4+ reducibility by compensating for oxygen vacancies, the reducibility showed no correlation with ammonia synthesis activity. However, Ru/Ce0.5La0.4Ti0.1O1.8 showed the highest activity originating from the facilitated formation of mesopores.

Stent graft in abdominal aortic aneurysm collapsed suddenly after thoracic endovascular aortic repair.

Stent graft collapse due to aortic dissection is an extremely rare event. Although endovascular aneurysm repair (EVAR) and thoracic endovascular aortic repair (TEVAR) are increasingly being performed, various complications can occur. We report a case of collapse of a stent graft, which was used to repair an abdominal aortic aneurysm (AAA) after TEVAR for thoracic aortic aneurysm (TAA). A 72-year-old man with a 77 mm AAA and 60 mm TAA underwent EVAR and a TEVAR 2 months later, respectively. CT performed after the TEVAR showed thoracic aorta dissection with associated AAA stent graft collapse. The graft collapsed was due to superior mesenteric artery obstruction. An emergency TEVAR was performed, and the procedure improved the collapsed graft; however, the endoleak of the AAA stent graft persisted. The AAA expanded over several days, warranting an open repair. Our case provides an insight into the cautionary indications for endovascular therapy.