Computational fluid dynamics of internal mammary artery-left anterior descending artery anastomoses.

OBJECTIVES: The aim of this study was to elucidate the remodelling of the internal mammary artery (IMA)-left anterior descending artery anastomosis and compare 2 different anastomosis techniques (end-to-side versus side-to-side) using computational fluid dynamics. METHODS: This study included 9 patients. Computed tomography (CT) angiography was performed immediately after coronary artery bypass grafting (CABG) and at 3-6 months later. The computational fluid dynamics models were made using the CT data. The pulsatile 3-dimensional blood flow was achieved with the finite volume method to evaluate the postoperative morphological and haemodynamic changes at the anastomosis in each patient. Flow velocity distribution, wall shear stress (WSS) and its fluctuation oscillatory shear index were measured. RESULTS: No early or mid-term graft occlusion was observed in the study series. In the side-to-side anastomosis, pouch formation at the distal end of IMA caused a vortex flow with low WSS immediately after CABG. However, at 3-6 months after surgery, this pouch disappeared. As a result, the laminar straight flow with uniform WSS distribution was achieved inside the anastomosis. In the end-to-side anastomosis, the anastomosis shape was remodelled, resulting in a laminar flow pattern with uniform WSS distribution. A patchy high oscillatory shear index was detected at the IMA wall on the top of anastomosis in either anastomosis techniques immediately after the surgery, but it disappeared at 3-6 months after surgery. CONCLUSIONS: Regardless of the anastomosis technique used, a successful remodelling of the IMA-left anterior descending artery anastomosis shape was achieved a few months after surgery, resulting in a straightforward flow streamline, with uniform WSS distribution and minimal oscillatory shear index.

Coronary Arteriovenous Fistula Draining Into Persistent Left Superior Vena Cava.

A 75-year-old woman was referred to our hospital for dyspnea and edema of the lower limbs. Computed tomography angiography revealed a dilated left coronary artery from the left main trunk to the left circumflex branch and a dilated fistula originating from the left circumflex branch and draining into the persistent left superior vena cava. Physical examination revealed pulmonary hypertension and congestive heart failure. We performed closure of the fistula and left main coronary artery orifice and coronary artery bypass grafting. Postoperative computed tomography angiography showed patency of all grafts and progression of thrombosis in the dilated abnormal vessels.

A Safe Technique for Using an Enclose II Anastomosis Assist Device During Off-Pump Coronary Bypass.

Several proximal anastomosis devices have been developed to facilitate the creation of a clampless, hand-sewn coronary artery bypass-to-ascending aorta anastomosis. An Enclose II anastomosis assist device (Novare Surgical Systems, Cupertino, CA) is a device commonly used for this purpose. We demonstrate a new, easy, and safe technique for cutting the aortic wall and making a punch hole over the aorta.

[Left Ventricular Pseudoaneurysm after an Apical Approach Transcatheter Aortic Valve Implantation;Report of a Case].

A 79-years-old woman was diagnosed with severe aortic stenosis and referred to our institution for the purpose of an operation. We decided to perform transfemoral transcatheter aortic valve implantation because of her high frailty due to her age and medication of long-term steroid for chronic rheumatoid arthritis. In the operation, left ventricular perforation occurred by the guide wire and cardiac tamponade was detected. We performed pericardial drainage and controlled bleeding through the 5th intercostal thoracotomy and trasncatheter aortic valve implantation was performed after that. Postoperative computed tomography (CT) demonstrated left ventricular pseudoaneurysm in the apex. We performed re-operation because of the enlargement of pseudoaneurysm. The operation was performed through median sternotomy and the pseudoaneurysm was repaired. The patient was discharged after postoperative CT demonstrated the left ventricular wall repaired.

Supravalvular aortic stenosis after arterial switch operation.

Supravalvular aortic stenosis as a late complication of transposition of the great arteries is very rare, and only a few cases have been reported. We describe the case of a 14-year-old girl who developed supravalvular aortic stenosis as a late complication of the arterial switch operation for transposition of the great arteries. The narrowed ascending aorta was replaced with a graft. The right pulmonary artery was transected to approach the ascending aorta which adhered severely to the main pulmonary trunk, and we obtained a good operative field.

[Successful management of nonocclusive mesenteric ischemia after aortic valve replacement;report of a case].

Non-occlusive mesenteric ischemia (NOMI) is a fatal complication after cardiovascular surgery, but early diagnosis is difficult because the clinical symptoms are not specific. We report a case of NOMI with successful management due to early diagnosis and treatment. A 78-year-old male complained of sudden abdominal pain after aortic valve replacement. NOMI was suspected because his laboratory work-up showed elevated serum transaminase, and computed tomography showed no mesenteric artery obstruction. We started a continuous intravenous infusion of prostaglandin E1, and performed emergency arterial angiography. Since angiography showed vasospasm of the mesenteric artery, we also started a continuous intra-arterial infusion of papaverine. Each vasodilator drug was started within a few hours after the onset of NOMI. His subsequent hospital course was uneventful, and he was discharged without enterectomy or fatal intestinal necrosis.

Valve-sparing neoaortic root replacement late after the Norwood and Fontan procedures.

Neoaortic root dilatation is a significant and inevitable late complication in patients after the Norwood operation. In this report, we describe a patient who had left pulmonary artery compression and severe neoaortic regurgitation from a severely dilated neoaortic root 11 years after the Norwood operation and subsequent Fontan procedure. We performed successful valve-sparing neoaortic root replacement in this patient.

[The treatment strategy for hypoplastic left heart syndrome].

In the recent years, the outcomes of treatment for hypoplastic left heart syndrome (HLHS) is improved because of perioperative management and procedure. We adopt a strategy of the primary Norwood procedure basically for neonates with HLHS, however bilateral pulmonary artery banding precede in patients with risk factors. In the Norwood procedure, aortic arch is reconstructed without artificial prostheses and pulmonary blood flow is supplied from the Blalock-Taussig shunt or the right ventricle-pulmonary artery shunt by case. We administer high dose vasodilators and nitric oxide gas with low resistance strategy after the Norwood procedure. The survival rate of patients with HLHS after 2005 is 84.2% in this strategy.