Hidetake Kawajiri

Impact of Chronic Kidney Disease on Long-Term Outcome of Coronary Artery Bypass Grafting in Patients With Diabetes Mellitus

BACKGROUND The aim of this study was to compare the short- and long-term outcomes of CABG in diabetes mellitus (DM) patients according to eGFR. METHODS AND RESULTS A total of 573 DM patients receiving CABG between 1997 and 2012 were stratified according to preoperative eGFR: normal or mild chronic kidney disease (CKD), eGFR ≥60 ml/min/1.73 m(2); moderate CKD, eGFR 30-60 ml/min/1.73 m(2); severe CKD, eGFR <30 ml/min/1.73 m(2); and severe CKD requiring hemodialysis (HD). Off-pump and bilateral internal thoracic artery (BITA) grafting rates were 83.4 and 62.3%, respectively. Mediastinitis and in-hospital mortality rates were both 1.4%. On logistic regression analysis, preoperative congestive heart failure and CKD severity were independent predictors of postoperative renal failure and major complications. The mean follow-up period was 5.7 years (range, 0-15.5 years). Estimated 5-year survival (92.9±1.6%, 82.8±3.3%, and 47.3±7.0%, respectively, P<0.001) significantly decreased with declining kidney function. On Cox hazard modeling, CKD severity was an independent predictor of major cerebrocardiovascular events (normal/mild: hazard ratio [HR], 1; moderate: HR, 1.35; severe: HR, 1.83; HD: HR, 2.0, P=0.016) and of overall survival (normal/mild: HR, 1; moderate: HR, 1.65; severe: HR, 5.96; HD: HR, 10.93, P<0.001). BITA grafting was a strong protective factor for overall survival (HR, 0.63; P=0.022). CONCLUSIONS In DM patients, early- and long-term outcomes after CABG are strongly influenced by CKD progression.

Endocardial linear infarct exclusion technique for infarcted lateral wall

We report a novel method of surgical ventricular restoration for an infarcted lateral wall: the endocardial linear infarct exclusion technique. First, transmural ventriculotomy is performed at the centre of the scar longitudinally along the coronary artery. Second, the inner layer is sutured in a longitudinal direction with 4-0 polypropylene continuous sutures to approximate the border between the normal and infarcted myocardium. Finally, the outer layer is closed with a combination of interrupted buttress and continuous over-and-over sutures with outer felt reinforcement. The advantages of endocardial linear infarct exclusion technique are as follows: the risk of bleeding is low; it is not technically demanding and is reproducible; the coronary artery can be preserved; approximation of the base of the anterior and posterior papillary muscles is possible in the case of ischaemic mitral regurgitation and it can also be applied to the anterior and inferior walls.

Development of tissue-engineered self-expandable aortic stent grafts (Bio stent grafts) using in-body tissue architecture technology in beagles.

In this study, we aimed to describe the development of tissue-engineered self-expandable aortic stent grafts (Bio stent graft) using in-body tissue architecture technology in beagles and to determine its mechanical and histological properties. The preparation mold was assembled by insertion of an acryl rod (outer diameter, 8.6 mm; length, 40 mm) into a self-expanding nitinol stent (internal diameter, 9.0 mm; length, 35 mm). The molds (n = 6) were embedded into the subcutaneous pouches of three beagles for 4 weeks. After harvesting and removing each rod, the excessive fragile tissue connected around the molds was trimmed, and thus tubular autologous connective tissues with the stent were obtained for use as Bio stent grafts (outer diameter, approximately 9.3 mm in all molds). The stent strut was completely surrounded by the dense collagenous membrane (thickness, ∼150 µm). The Bio stent graft luminal surface was extremely flat and smooth. The graft wall of the Bio stent graft possessed an elastic modulus that was almost two times higher than that of the native beagle abdominal aorta. This Bio stent graft is expected to exhibit excellent biocompatibility after being implanted in the aorta, which may reduce the risk of type 1 endoleaks or migration.

Coronary Artery Bypass Grafting in a Patient with Polyarteritis Nodosa Presenting with Acute Myocardial Infarction and Multiple Coronary Aneurysms

Polyarteritis nodosa (PAN) is a necrotizing form of vasculitis that affects small- and medium- sized vessels. Cases of ischemic heart disease involving coronary aneurysms in patients with PAN have been reported previously, but there have only been a few reports of coronary artery surgery for PAN-related coronary disease. A 46-year-old female with a history of PAN arrived at our emergency room due to cardiopulmonary arrest. After cardiopulmonary resuscitation, emergent coronary angiography was performed, because an electrocardiogram demonstrated ST segment elevation in leads V1 to V5. Coronary angiography revealed occlusion of the proximal right coronary artery and left anterior descending coronary artery as well as multiple coronary aneurysms. We performed emergent two-vessel coronary artery bypass grafting (the left anterior descending coronary artery and posterolateral branch of the circumflex system were treated with grafts from the left internal mammary artery and saphenous vein graft, respectively) under percutaneous cardiopulmonary support without cardiac arrest. The patients postoperative course was uneventful, and postoperative coronary angiography revealed that the bypass grafts were patent. A review of the literature and a discussion of this case are also presented.

Longitudinal rupturing of a knitted Dacron graft 30 years after its implantation

A 79-year old man with a pulsatile mass in his left groin was admitted to our institution in 2012. He had undergone an aortobifemoral bypass using a bifurcated Cooley double velour knitted Dacron graft for aortoiliac occlusive disease in 1982. Computed tomography detected a 34 mm para-anastomotic pseudoaneurysm in the left limb of the graft. Graft replacement was performed to prevent the aneurysm from rupturing, and we found that the old Dacron graft had ruptured longitudinally along its guideline. The disrupted portion of the old Dacron graft was excised and examined by scanning electron microscopy, which revealed the deterioration of the polyester filaments around the guideline.

Endovascular Repair of Traumatic Aortic Injury Using a Modified, Commercially Available Endograft to Preserve Aortic Arch Branches

A 25-year-old woman was admitted to our hospital after being involved in a high-speed motorcycle accident. Computed tomography angiography revealed a blunt traumatic aortic injury of the lesser curvature of the distal aortic arch accompanied by splintered fractures of the seventh thoracic vertebra and left clavicle. If the pseudoaneurysm had been treated with open surgical repair, then arch replacement under cardiopulmonary bypass, which was considered to be too invasive, would have been necessary. Therefore, thoracic endovascular aortic repair (TEVAR) was preferred as a first-line treatment to prevent pulmonary complications and hemorrhaging. Because the proximal landing zone for TEVAR was insufficient, we used a modified (fenestrated) commercially available endograft to preserve the branches of the aortic arch. Postoperative computed tomography scans confirmed that the pseudoaneurysm had been excluded without the endoleaks, and the aortic arch branches were patent. The patients postoperative course was uneventful, and she was discharged from the hospital to have surgery for a vertebral fracture on postoperative day 6.

Aneurysm formation at both ends of an endograft associated with maladaptive aortic changes after endovascular aortic repair in a healthy patient.

We report a case in which saccular aneurysms formed at both ends of an endograft that exhibited maladaptive aortic changes after endovascular aortic repair in a patient without significant evidence of connective tissue disease. A 66-year old male underwent thoracic endovascular aortic repair (TEVAR) for a distal aortic arch aneurysm. A follow-up computed tomography (CT) scan performed at 6 months after the TEVAR detected a small saccular aneurysm at the distal edge of the endograft. At 10 months after the TEVAR, a new large aneurysm appeared at the proximal edge of the endograft. To prevent the latter aneurysm rupturing, total arch replacement with endograft fixation was performed. A CT scan obtained at 18 months after the TEVAR demonstrated that the aneurysm at the distal edge of the endograft had progressed and so we considered reintervention. Unfortunately, the patient died of intracranial haemorrhaging before the second procedure could be carried out. A histopathological examination of the aneurysm wall did not detect any significant background factors, such as connective tissue disease, inflammation or infection. The present case involved unexpected late complications, which might have been caused by changes in the form of the aorta after TEVAR.

Two-Stage Hybrid Repair of Kommerell Diverticulum with Supra-Aortic Debranching

OBJECTIVES The surgical treatment of Kommerell diverticula is associated with high mortality and morbidity rates. In the mid-2000s, hybrid aortic arch repair was developed, and the procedure has since been used to repair Kommerell diverticula. In the present study, we focused on the postoperative outcomes of two-stage hybrid repair of Kommerell diverticula that required supra-aortic debranching (type I hybrid arch repair). METHODS From August 2010 to July 2013, a total of four patients (aged 73.5 ± 9.5 years) underwent two-stage hybrid repair (type I hybrid arch repair) for Kommerell diverticula, and their cases were retrospectively studied. All four patients had right aortic arches and aberrant left subclavian arteries. The repair procedure consisted of two stages: (1) debranching of the supra-aortic vessels via a median sternotomy; (2) exclusion of the Kommerell diverticulum by performing thoracic endovascular repair via a femoral approach and coil embolization of the orifice of the aberrant subclavian artery. RESULTS There were no in-hospital deaths. One patient developed an acute kidney injury and required hemodialysis on postoperative day 2, although his renal function recovered within 48 hours. No strokes, paraplegia, or early aortic events were observed in our series. The mean follow-up period was 19.5 months (range, 5-47 months). All patients remained free from aortic events and endoleaks during the follow-up period. CONCLUSION The early and mid-term outcomes of hybrid repair for Kommerell diverticula that require supra-aortic debranching, which are less invasive and do not involve hypothermic circulatory arrest, are acceptable. However, this procedure requires the insertion of an endograft into the ascending aorta, and careful and long-term follow-up is required to confirm its efficacy.

Design optimization method for Francis turbine

This paper presents a design optimization system coupled CFD. Optimization algorithm of the system employs particle swarm optimization (PSO). Blade shape design is carried out in one kind of NURBS curve defined by a series of control points. The system was applied for designing the stationary vanes and the runner of higher specific speed francis turbine. As the first step, single objective optimization was performed on stay vane profile, and second step was multi-objective optimization for runner in wide operating range. As a result, it was confirmed that the design system is useful for developing of hydro turbine.

Infectious pseudoaneurysm at the proximal edge of the endograft, after hybrid aortic arch repair

A 77-year old woman who underwent hybrid aortic arch repair using a Gore-TAG (Gore-Associates, Flagstaff, AZ, USA) endograft (Fig. 1A) complained of chest pain 5 months after operation. Blood cultures revealed Serratia marcescens. Computed tomography (CT) demonstrated dislocation of the endograft with formation of a pseudoaneurysm (Fig. 1B). Ascending aorta replacement with re-debranching was emergently performed (Fig. 2).