Michiaki Imamura

Surgical management of atherosclerotic aortic arch aneurysms using selective cerebral perfusion: 7-year experience in 52 patients

OBJECTIVE Patients with atherosclerotic aortic arch aneurysms are at greater risk for brain complication. We report our techniques and results of operation using selective cerebral perfusion. METHODS We retrospectively analyzed 52 consecutive patients with atherosclerotic aortic arch aneurysms (mean age, 70 years, range, 53-86 years), who underwent operation between April 1992 and March 1999. The operation was non-elective in 11 patients (21.1%). Concomitant operations included eight coronary artery bypass grafting and one aortic valve replacement. Simultaneous distal aortic reconstruction was performed in three patients. The operation was performed through median sternotomy. To avoid brain embolism, total arch replacement with a branched prosthesis was performed in 48 patients, in an attempt to exclude affected segments of aorta. In addition, retrograde femoral artery perfusion was avoided and cerebral circulation was isolated before aortic manipulation. To achieve even blood flow distribution, we employed perfusion and continuous pressure monitoring of all the three arch vessels. The perfusion rate was 12+/-2 ml/kg per min and the pressure was kept around 50 mmHg. Deep hypothermic arrest of the lower torso (bladder temperature, 22 degrees C) was used during open distal aortic anastomosis. RESULTS The hospital mortality rate was 11.5% (six of 52), and 7.3% (three of 41) for elective cases. Only one patient (1. 9%) developed permanent focal neurological deficit. Six other patients showed temporary brain complications, which was global (delirium) in three and focal in three others. CONCLUSIONS Selective cerebral perfusion is a safe brain protection method, and our strategy seems effective for embolic stroke prevention.

Giant pseudoaneurysm of the right ventricular outflow tract after repair of truncus arteriosus: evaluation by MR imaging and surgical approach

One year after surgical repair of the truncus arteriosus, a 1-year 8-month-old boy was found to have a pseudoaneurysm of the right ventricular outflow tract (RVOT). Cine-magnetic resonance imaging (MRI) showed a narrow communication between the RVOT and aneurysm. MRI was useful to evaluate the anatomical and spatial relations between the pseudoaneurysm and the surrounding structures, therefore an appropriate approach was chosen. Thus, a median sternotomy approach was carried out and ordinary central cannulation was feasible to establish a cardiopulmonary bypass. The defect was successfully repaired with reconstruction using a monocuspid outflow patch. MRI provided useful information for deciding the surgical approach.

Cardioprotective effect of perfluorochemical emulsion for cardiac preservation after six-hour cold storage

Perfluoro-octyl bromide (PFOB) emulsion is capable of transferring oxygen to tissues even at 4°C, suggesting an application in myocardial preservation. We evaluated the cardioprotective effect of PFOB emulsion added to the storage solution. Guinea pig hearts were isolated (n = 24) and perfused with Krebs-Henseleit solution (KHS) and then cooled and perfused with St. Thomas Hospital II solution (STS). The hearts were stored in three different solutions: STS (STS group), oxygenated (O2) STS (O2 STS group), and O2 STS with PFOB emulsion (30 %) (O2 STS + PFOB group) for 6 hours at 4°C. After storage, rewarming was performed, followed by reperfusion with KHS. Left ventricular developed pressure of O2 STS + PFOB group was significantly higher than that of the other groups during reperfusion (p < 0.01). There was no difference among the three groups in O2 extraction and cardiac efficiency; however, cardiac oxygen consumption in the O2 STS + PFOB group significantly improved during reperfusion. In the O2 STS + PFOB group, creatinine kinase, lactate dehydrogenase, and myocardial water content were significantly decreased (p < 0.01). This study suggests that PFOB emulsion is beneficial for the cardioprotection of donor hearts, allowing a prolonged cardiac storage time.

Neutrophil-independent myocardial dysfunction during an early stage of global ischemia and reperfusion of isolated hearts.

The effect of global ischemia and reperfusion on the expression of cytokine genes and cell adhesion molecules by myocardial tissues and neutrophils was studied by using the Langendorff model. Although cardiac function deteriorated after reperfusion of ischemic hearts, there was no evidence of inflammation and myocardial degeneration, which is in contrast to previous findings that neutrophil-mediated inflammation is a critical step in post-ischemic reperfusion injury in regional ischemia. Flow cytometry analysis demonstrated that the global ischemia and reperfusion did not affect the expression of adhesion molecules on neutrophils. We also examined the expression of various cytokines which are involved in inflammatory responses. Only interleukin 1 alpha was induced after the reperfusion of the ischemic hearts. These results suggest that neutrophils barely contribute to the myocardial dysfunction and IL-1 alpha may play a role in post-ischemic myocardial dysfunction during the early stage of reperfusion.

Simplified Technique for Patch Augmentation and Chorda Reconstruction of Left Atrioventricular Valve in Complete Atrioventricular Septal Defect

Abstract Management of the left AV valve is the most crucial component of the repair of complete atrioventricular septal defect (cAVSD). A scarcity or deficiency of leaflet tissue may compromise satisfactory repair in a small number of patients with cAVSD, especially in patients with a normal karyotype. We describe the case of a 44‐day‐old baby who had cAVSD with severe left atrioventricular valve regurgitation due to dysplastic bridging leaflets. The repair was successfully performed by augmenting leaflet tissue and reconstructing the chorda using single patch. This technique could be one of the options in the repair of valves in order to avoid valve replacement in a small infant, although material of patch and reoperation need to be considered. (J Card Surg 2003;18:253‐256)