Hybridization of Step-/Chain-Growth and Radical/Cationic Polymerizations Using Thioacetals as Key Components for Triblock, Periodic and Random Multiblock Copolymers with Thermoresponsiveness.

A novel strategy for synthesizing a series of multiblock copolymers is developed by combining radical/cationic step-growth polymerizations of dithiols and divinyl ethers and chain-growth cationic degenerative chain-transfer (DT) polymerizations of vinyl ethers using thioacetals as key components. The combination of radical step-growth polymerization and a cationic thiol-ene reaction or cationic step-growth polymerization enables the synthesis of a series of macro chain-transfer agents (CTAs) composed of poly(thioether) and thioacetal groups at different positions. The resulting products are 1) bifunctional macro CTAs with thioacetal groups at both chain ends, 2) periodic macro CTAs periodically having thioacetal groups in the main chain, and 3) random macro CTAs randomly having thioacetal groups in the main chain. Subsequently, the obtained macro CTAs are used for chain-growth cationic DT polymerization of methoxyethyl vinyl ether (MOVE) to result in 1) triblock, 2) periodic, and 3) random multiblock copolymers consisting of poly(thioether) and poly(MOVE) segments. All these triblock and multiblock copolymers composed of hydrophobic poly(thioether) and hydrophilic poly(MOVE) segments show an amphiphilic tendency to form characteristic micelles in aqueous solutions. In addition, due to the thermoresponsive poly(MOVE) segments, the obtained copolymers exhibit lower critical solution temperatures that depend on the segment sequences and lengths.

[Self-made Bovine Pericardial Roll Graft Replacement of Infected Aneurysm Following Thoracic Endovascular Aortic Repair;Report of a Case].

A 72 years-old man was admitted with fever and cough. He had undergone aortic arch graft replacement with elephant trunk and endovascular stent graft for distal arch aortic aneurysm 1 year ago. Additionally, he had treated type I endoleak with an endovascular stent graft 3 month previously. Computed tomography showed soft tissue around the aneurysm and visible gas bubble within intramural thrombus, and he was diagnosed with stent graft infection. The stent graft was removed and aortic reconstruction was performed using bovine pericardial roll grafts. The grafts were covered with the greater omentum. He was discharged on the 48th postoperative day, and was alive and well 4 years after the operation.

Thiol-Ene Cationic and Radical Reactions: Cyclization, Step-Growth, and Concurrent Polymerizations for Thioacetal and Thioether Units.

Thiol-ene cationic and radical reactions were conducted for 1:1 addition between a thiol and vinyl ether, and also for cyclization and step-growth polymerization between a dithiol and divinyl ether. p-Toluenesulfonic acid (PTSA) induced a cationic thiol-ene reaction to generate a thioacetal in high yield, whereas 2,2'-azobisisobutyronitrile resulted in a radical thiol-ene reaction to give a thioether, also in high yield. The cationic and radical addition reactions between a dithiol and divinyl ether with oxyethylene units yielded amorphous poly(thioacetal)s and crystalline poly(thioether)s, respectively. Under high-dilution conditions, the cationic and radical reactions resulted in 16- and 18-membered cyclic thioacetal and thioether products, respectively. Furthermore, concurrent cationic and radical step-growth polymerizations were realized using PTSA under UV irradiation to produce polymers having both thioacetal and thioether linkages in the main chain.

[Migration of a Temporary Epicardial Pacing Wire into the Aorta Following Open Heart Surgery].

The patient was a 76-year-old female. An epicardial pacing wire was inserted in an open heart surgery. As there was some resistance when extracting it, it was cut off at the cutaneous level. Ten months after discharge, she was referred to our hospital for further examination due to a flap found in the left external carotid artery by the carotid echography. The remaining wire was found between the ascending aorta and the left external carotid artery by computed tomography (CT). It was considered that the wire, with no resistance after being cut off, became isolated, pierced the ascending aorta, moved further by the heart beat, and reached the left external carotid artery. Surgery was performed via median re-sternotomy and left common carotid artery incision, since the proximal edge of the wire remained in the mediastinal space. It is quite rare for a remaining pacing wire to migrate into the aorta.

[Surgical Outcomes for Aortic Root Repair in Patients Undergoing Type A Acute Aortic Dissection].

We evaluated retrospectively 11 consecutive patients who underwent emergent aortic root operations for acute aortic dissection from April 2012 to March 2017. We underwent Bentall operation in 6 patients and Florida Sleeve repair in 3 patients and aortic root replacement with a Freestyle stentless porcine valve in 2 patients. The 30-day mortality of emergent aortic root operations was 9.1%(1 of 11), and the hospital mortality was 18.2%(2 of 11). The Overall survival at 5 years was 90.0%. In conclusion, the aortic root repair can be performed safely in acute aortic dissection.

Four-stitch side-to-side anastomosis for sequential coronary artery bypass grafting.

Sequential bypass (SB) is an effective method of implementing complete myocardial revascularization of complex coronary stenoses. The SB allows a single graft to be used for bypass in several locations, which facilitates multi-branch revascularization. We have developed a simple SB technique, four-stitch side-to-side anastomosis, and report its clinical effectiveness in 428 patients.

Preventive effect of intraoperative landiolol administration on atrial fibrillation after off-pump coronary artery bypass grafting.

INTRODUCTION: Postoperative atrial fibrillation (AF) is a common complication of cardiac surgery that is associated with an increased incidence of other complications. This study evaluated the safety and efficacy of landiolol hydrochloride--an ultrashort-acting ß1-selective blocker and highly regulated drug, positioned as a class 1 antiarrhythmic in Japan guidelines--for the prevention of AF after off-pump coronary artery bypass grafting (CABG). METHODS: Between January 2011 and November 2013, 116 patients underwent CABG at Fukuoka University Hospital. They were divided into two groups: group L consisted of patients who were administered landiolol hydrochloride at 2 µg/kg/min after completion of all distal anastomoses; group C was the control group consisting of patients who were not administered landiolol. Patient backgrounds, intraoperative variables and incidence of postoperative complications were compared. RESULTS: No significant between-group differences were observed in patient backgrounds or incidence of complications other than postoperative AF, which occurred significantly less frequently in group L. After administration of landiolol, heart rate decreased but no change was observed in arterial pressure or other parameters, and patient hemodynamics remained stable. CONCLUSION: Intraoperative and perioperative administration of low-dose landiolol has a preventive effect on the development of AF after CABG surgery.

Safety and efficacy of ascending aorta cannulation during repair of acute type A aortic dissection (PA29-04): "Presented at the 65th Annual Scientific Meeting of the Japanese Association for Thoracic Surgery".

OBJECTIVE: Antegrade central perfusion for acute Stanford type A aortic dissection prevents malperfusion and retrograde cerebral embolism during cardiopulmonary bypass. Prompt establishment of antegrade perfusion via the ascending aorta may improve surgical results of type A dissections, especially in situations of hemodynamic instability. Thus, we evaluated the safety and efficacy of cannulation of the dissected ascending aorta in acute type A dissection. METHODS: We reviewed the medical charts of patients undergoing repair of acute ascending aortic dissection (n = 52) from April 2010 to April 2013. Cannulation was accomplished in 29 patients via the ascending aorta (central) and in 23 patients via the femoral or axillary artery (peripheral). The ascending aorta was routinely cannulated using Seldinger technique under epiaortic ultrasound guidance. Comorbidities, mortality, complications, and durations of hospital stays were compared for the groups. RESULTS: In all cases, routine cannulation of the ascending aorta was safely performed with no resultant malperfusion or thromboembolism. Mean operative duration, cardiopulmonary bypass time, intubation time, and intensive care unit stay were significantly shorter in the central group. Two patients (6.8 %) in the central group died compared with four patients (17.3 %) in the peripheral group (P = 0.005). CONCLUSIONS: Antegrade central perfusion via the ascending aorta, a simple and safe technique that enables rapid establishment of antegrade systemic perfusion, was as safe as peripheral cannulation in patients with type A acute aortic dissection.

[Left coronary ostial stenosis and aortic regurgitation associated with syphilitic aortitis; report of a case].

We report a surgical case of severe left coronary ostial stenosis and aortic regurgitation associated with syphilitic aortitis. A 46-year-old man was referred to our hospital for further examination of effort angina pectoris. Coronary angiography and echocardiography showed severe left coronary ostial stenosis and aortic regurgitation. We initiated treatment with penicillin G injections and an emergency surgery was performed 8 days later. Aortic valve replacement (SJM #23) and coronary artery bypass grafting were also performed. We used in situ left internal thoracic artery (ITA) and right gastroepiploic artery (GEA) to prevent stenosis of the proximal anastomotic site in the late postoperative period. The postoperative course was uneventful.

[Bleeding complication from the elephant trunk graft at the 2nd stage operation of the total aortic replacement].

We described a rare complication that occurred during the 2nd stage of a total aortic replacement. The patient was a 72-year-old male who presented with type B acute aortic dissection complicated by distal arch aneurysm. Following the replacement of the total arch aorta with an elephant trunk graft (22 mm Gelweave graft), the descending and abdominal aorta enlarged rapidly. After about 3 months, he was scheduled for the 2nd operation. Through the 8th intercostal space and under partial cardiopulmonary bypass, the descending and the abdominal aorta was replaced with a 20 mm Gelweave-Coselli graft. The 12th intercostal artery, celiac trunk, superior mesenteric artery (SMA), and bilateral renal arteries were reconstructed. During the operation, severe bleeding began from the entire elephant trunk graft. After heparin neutralization and a massive transfusion of blood, fresh frozen plasma, and platelet-rich plasma, the bleeding was controlled. However, paraplegia occurred probably because of severe intraoperative hypotension. Careful attention should be paid during the 2nd stage of an elephant trunk operation.

[Aortic dissection after aortic valve replacement for bicuspid aortic valve complicated with ascending aortic dilatation; report of a case].

Congenital bicuspid aortic valve (BAV) is known to be a predisposing factor for aortic aneurysms and dissection because of intrinsic weakness of the aortic wall. We report here a case of 58-year-old man who developed type A aortic dissection 40 months after aortic valve replacement (AVR) for a congenital BAV. The ascending aorta diameter was 48 mm at the time of AVR. Computed tomography revealed ascending aortic dilatation (maximum diameter 64 mm) complicated with aortic dissection. We performed aortic root replacement and total arch replacement successfully. He has been doing well after the operation. In patients of congenital BAV with a baseline ascending aortic diameter of >40 mm, especially in young patients, complete replacement of the ascending aorta at the time of AVR should be considered in order to prevent future aortic complications.

Unexpectedly large aortoesophageal fistula inconsistent with CT imaging due to the thrombus working as the tamponade.

A 69-year-old woman with a history of graft replacement of descending aortic aneurysm was referred to our hospital due to massive hematemesis with shock status. Additionally, the deterioration of respiratory status made us start the management under mechanical ventilation. The emergent gastrointestinal endoscopy by a general practitioner showed ulcer-like lesion of the upper esophagus and arterial bleeding. A contrast-enhanced computed tomography showed thoracic aortic aneurysm surrounded by low density mass and contrast medium protruding from the aneurysm. The findings suggested that thoracic aortic aneurysm perforated into esophagus and made an aortoesophageal fistula. Hemodynamic deterioration rapidly progressed and she passed away 4 days after her hospitalization. Autopsy showed that a new thoracic aortic aneurysm arose from the proximal site of the graft. The aneurysm ruptured to esophagus with 6.0 cm x 5.0 cm sized fistula. The fistula was filled with a large thrombus. The large thrombus filling with the fistula worked as the tamponade and prevented her from the fatal exsanguinations and sudden death. The mechanism of the sentinel bleeding and the fatal exsanguinations known as Chiari's triad was revealed in our report.