Impact of top end anastomosis design on patency and flow stability in coronary artery bypass grafting.

For coronary artery bypass grafting (CABG), free grafts such as a saphenous vein or radial artery are often used for grafts to the lateral and posterior walls. However, the relationship between top-end anastomosis design and long-term patency remains unknown. Because coronary artery blood flow is dominant during diastole, top-end anastomosis may work better if the graft is directed towards the apex, whereas the shortest graft pathway appears to be most efficient. Using computational fluid dynamic models, we evaluated the hemodynamic variables that were affected by the angle of the top-end anastomosis. We created three-dimensional geometries of the aortic root with coronary arteries that involved 75 % stenosis in the obtuse marginal and postero-lateral branches. Two bypass models under vasodilator administration were created: in a"Model A", the top-end anastomosis is parallel to the long axis of the ascending aorta and the graft passed over the conus directed towards the apex; in a "Model B", the top-end anastomosis is directed toward the shortest pathway, and form near the right angles to the long axis of the ascending aorta. Wall shear stress (WSS) and its fluctuation, an oscillatory shear index (OSI) were evaluated to predict fibrosis progression at the anastomosis site and graft flow. Graft flow was 197.3 ml/min and 207.3 ml/min in the "Model A" and "Model B", respectively. The minimal WSS value inside the graft with the "Model A" and "Model B" was 0.53 Pa and 4.09 Pa, respectively, and the OSI value was 0.46 and 0.04, respectively. The top-end anastomosis of a free graft should be directed vertically towards the aorta to achieve the shortest graft pathway to maintain a high graft flow rate and to avoid the risks of endothelial fibrosis and plaque progression over the long-term after CABG.

Optimal bypass graft design for left anterior descending and diagonal territory in multivessel coronary disease.

OBJECTIVES: Coronary artery bypass grafting for multivessel disease requires an appropriate graft design to avoid the competition of flow between the graft and the native vessel in order to achieve a sufficient coronary flow and durable graft patency. METHODS: Three-dimensional computational models of the left coronary artery were created based on the angiographic data. Three stenosis patterns of 75 and 90% combinations were created in the left anterior descending artery (LAD), the diagonal branch (Dx) and the circumflex artery (LCx). The left internal thoracic artery (LITA) was anastomosed to the LAD, and separate saphenous vein grafts (SVGs) were anastomosed to the Dx and the LCx in the 'Independent' model. The 'Sequential' model included sequential SVG anastomoses to the Dx and the LCx with a left internal thoracic artery-left anterior descending artery bypass, and Y-composite arterial grafts to LAD and Dx were created in the 'Composite' model. RESULTS: The 'Independent' model had high reverse flow from the Dx to the LAD in systole, resulting in decreased LITA flow when Dx stenosis was mild. The 'Sequential' model also had reverse flow in diastole, resulting in additional LAD flow. The 'Composite' model distributed increased flow to the Dx when Dx stenosis was severe, resulting in decreased flow to the LAD. CONCLUSIONS: Systematic flow evaluation is beneficial for determining the optimal bypass graft arrangement in patients with multivessel disease. Individual SVG anastomoses to the Dx and the LCx are not desirable when Dx stenosis is not severe and a Y-composite arterial graft to the LAD and the Dx is not desirable when Dx stenosis is severe.

Key success factors for thoracic endovascular aortic repair for non-acute Stanford type B aortic dissection.

OBJECTIVES: We aimed to determine the key factors associated with successful early and late outcomes after thoracic endovascular aortic repair (TEVAR) for non-acute Stanford type B aortic dissection at our institution. METHODS: Inpatient and outpatient records were retrospectively reviewed. Patients operated on within 14 days after the onset of acute aortic dissection and those with rupture or malperfusion were excluded. RESULTS: Forty-five patients (mean age, 55.5 ± 13.1 years; 23-79 years) underwent 53 TEVAR operations for non-acute Stanford type B aortic dissection between 1998 and 2012. Thirty-four patients had a patent false lumen and 19 had an ulcer-like projection (ULP). No early mortality was observed. At late follow-up (7.5 ± 3.9 years) of the 45 patients, survival after the initial TEVAR was 100, 86 and 63%; freedom from aortic reintervention was 87, 73 and 59%; and freedom from open aortic surgery was 89, 84 and 73%, at 1, 5 and 10 years, respectively. Of 15 late deaths, 2 were due to aortic rupture and 2 were operative deaths associated with aortic surgery. Of the 34 patients with patent false lumens before TEVAR, 25 had their descending false lumens thrombosed; of these 25, 16 had remodelling of the descending aorta; and of these 16, 4 had complete obliteration of the false lumen of the entire aorta. By bivariate analysis, the site of the primary entry and age were significantly associated with thrombosis of the descending false lumen, maximum aortic diameter was associated with remodelling of the descending aorta, and absence of abdominal branches arising from the false lumen was associated with complete obliteration of the false lumen of the entire aorta. CONCLUSIONS: The early results of TEVAR for non-acute Stanford type B aortic dissection were favourable. However, for cases with patent false lumens, complete obliteration of the false lumen of the entire aorta was difficult to achieve. Absence of the primary entry at the outer curvature of the distal aortic arch, younger age, small aortic diameter and absence of the abdominal aortic branches arising from the false lumen were the key success factors.

Subacute presentation of right ventricular perforation after pacemaker implantation.

We report an 87-year-old woman with right ventricular perforation due to a permanent pacemaker lead detected 4-days after implantation. The pacemaker lead was seen to perforate through the myocardium and pericardium and to reach the left pleural cavity. We removed the wire surgically by median sternotomy. The pericardial effusion was cloudy and yellowish, suggesting infection. However, no bacteria were detected by bacterial cultures of the pericardial effusion and pacing wire. The patient developed neither mediastinitis nor sepsis after the operation, and a new pacemaker was implanted safely one month later.

Aortic valve replacement and concomitant coronary artery bypass grafting in a patient with infective endocarditis and anomalous origin of the right coronary artery from the opposite sinus of valsalva.

A 69-yrs-old woman with anomalous origin of the right coronary artery from the opposite sinus of Valsalva (ACAOS) was diagnosed as having infective endocarditis affecting the aortic valve. Transthoracic echocardiography showed severe aortic stenosis and vegetations on the cusp of the aortic valve, which necessitated aortic valve replacement. Before the operation, computed tomography showed a right-ACAOS, with the artery running an interarterial course between the aorta and pulmonary artery. ACAOS running an interarterial course has been reported to be associated with an increased risk of ischemic cardiac events and sudden death. The patient was treated successfully by the aortic valve replacement with concurrent coronary artery bypass grafting using a saphenous vein graft for the right coronary artery.

A case of autoimmune hepatitis exacerbated by the administration of etanercept in the patient with rheumatoid arthritis.

A 50-year-old woman was admitted for active rheumatoid arthritis (RA). She was found to have RA 1 year prior to this admission. Past history was unremarkable and she had no family history for rheumatic diseases. As nonsteroidal anti-inflammatory drug (NSAID) and methotrexate were not effective, etanercept was started (25 mg, twice a week). Mild elevation of alanine transaminase (ALT) and aspartate transaminase (AST) was found as an outpatient, and it was considered to be NSAID-induced liver injury. Two weeks after the first dose of etanercept, she developed progressive elevation of AST and ALT with right upper quadrant tenderness and hepatomegaly. Etanercept was discontinued and liver biopsy was performed, which demonstrated portal-area-dominant lymphoplasmacytic inflammatory cell infiltration. She was diagnosed as autoimmune hepatitis (AIH). Glucocorticoid was started with normalized liver function and stable joint symptoms. AIH was thought to be acutely aggravated by the administration of etanercept.