Clinical outcome after cardiac operations in patients with cirrhosis

BACKGROUND: To evaluate the clinical outcome after cardiac operations in patients with cirrhosis, a retrospective study was undertaken. METHODS: Between 1989 and 2003, 18 patients with cirrhosis who underwent cardiac operations were identified. Their preoperative status and postoperative clinical results were assessed. RESULTS: Ten patients were classified as having Child-Pugh class A cirrhosis, 7 as having class B cirrhosis, and 1 as having class C cirrhosis. Fifteen of 18 patients underwent cardiac surgery using cardiopulmonary bypass, and the remaining 3 patients with class B cirrhosis received coronary artery bypass grafting without cardiopulmonary bypass. In patients undergoing cardiopulmonary bypass, 60% of those with class A cirrhosis and 100% of those with class B cirrhosis and class C cirrhosis had postoperative major complications, including infection, respiratory failure, renal failure, bleeding, and gastrointestinal disorder. One of 3 patients (33%) with class B cirrhosis undergoing coronary artery bypass grafting without cardiopulmonary bypass had major complications. The overall postoperative mortality rate was 17%. Hospital mortality of patients with class A cirrhosis, class B cirrhosis, and class C cirrhosis undergoing cardiopulmonary bypass was 0%, 50%, and 100%, respectively. None of 3 patients with class B cirrhosis undergoing coronary artery bypass grafting without cardiopulmonary bypass died in this study. CONCLUSIONS: Although the incidence of major complications was high, patients with Child-Pugh class A cirrhosis tolerated cardiac surgery satisfactorily. Patients with more advanced cirrhosis, however, may not be suitable for elective cardiac operations with cardiopulmonary bypass. Although our results are not conclusive, coronary artery bypass grafting without cardiopulmonary bypass can be an alternative therapeutic strategy for patients with advanced cirrhosis requiring surgical revascularization.     

Resonant frequency control for artificial heart using online parameter identification

To develop effective medical care and therapeutic control using an artificial heart, a new control method has been developed. This new method can control the artificial heart effectively and can adapt to internal physiological behavior using measured physiological data; aortic pressure, aortic flow, and pump flow. This method consists of first, a second-order physiological model, which represents the internal physiological behavior by a mathematical equation; and second, an estimation method, which can identify the physiological parameters; aortic inertia, aortic resistance, aortic compliance, and peripheral resistance by a parameter identification method. It can then calculate the resonant frequency as the control signal for the artificial heart from the identified physiological model. To confirm the effectiveness, the proposed method was evaluated in a computer simulation study. This evaluation showed that the new method could estimate the physiological parameters and the resonant frequency within a 10% error. The impedance of the systemic circulation could also be reduced by this method.     

Epidural hematoma after an epidural block in a patient with no coagulopathy

We report a case of epidural hematoma after a single epidural block. The patient was a 67-year-old woman with sciatica and osteoarthritis of the spine. She had no coagulopathy. She underwent a single epidural block without difficulty 3 times in 5 days. She had a lumbar MRI for an examination of the spine 4 days after the final epidural block. Subacute epidural hematoma of 0.8 x 1.5 x 3.0 cm was revealed on MRI at L 3-4. She had no new neurological symptoms. MRI 1 month later revealed a resolution of the hematoma. Epidural hematoma after an epidural block might occur in an outpatient with no bleeding tendency.     

Case of systolic anterior motion of mitral valve after mitral valve repair

A 56-year-old woman was underwent mitral valve repair for prolapse of the posterior mitral leaflet. Intraoperative transesophageal echocardiography (TEE) showed systolic anterior motion (SAM) of the mitral valve at the weaning from cardiopulmonary bypass (CPB). Sliding technique was easily performed at the second pump run. Intraoperative TEE demonstrated no SAM or residual mitral regurgitation after the second pump run.     

Development of realistic high-resolution whole-body voxel models of Japanese adult males and females of average height and weight, and application of models to radio-frequency electromagnetic-field dosimetry

With advances in computer performance, the use of high-resolution voxel models of the entire human body has become more frequent in numerical dosimetries of electromagnetic waves. Using magnetic resonance imaging, we have developed realistic high-resolution whole-body voxel models for Japanese adult males and females of average height and weight. The developed models consist of cubic voxels of 2 mm on each side; the models are segmented into 51 anatomic regions. The adult female model is the first of its kind in the world and both are the first Asian voxel models (representing average Japanese) that enable numerical evaluation of electromagnetic dosimetry at high frequencies of up to 3 GHz. In this paper, we will also describe the basic SAR characteristics of the developed models for the VHF/UHF bands, calculated using the finite-difference time-domain method.     

MRI in the evaluation of hepatocellular nodules: role of pulse sequences and contrast agents

Magnetic resonance (MR) imaging is more useful than computed tomography (CT) in the evaluation of hepatocellular nodules based on the excellent soft-tissue image contrast of MR imaging. In addition, recent MR units have allowed various fast MR imaging techniques (i.e., parallel imaging or echo-planar imaging) to dramatically improve image quality and image contrast. A variety of liver-specific MR contrast agents are also currently available or have been evaluated in clinical trials to improve the contrast between the liver parenchyma and hepatocellular nodules.     

Mutations of BRAF are associated with extensive hMLH1 promoter methylation in sporadic colorectal carcinomas

Activating mutations of BRAF have been frequently observed in microsatellite unstable (MSI+) colorectal carcinomas (CRCs), in which mutations of BRAF and KRAS are mutually exclusive. Previously, we reported that hypermethylation of hMLH1 might play an important role in the tumorigenesis of right-sided sporadic CRCs with MSI showing less frequency of KRAS/TP53 alteration. Therefore, we have assumed that BRAF mutations might be highly associated with hMLH1 methylation status rather than MSI status. In this study, mutations of BRAF and KRAS and their relationship with MSI and hMLH1 methylation status were examined in 140 resected specimens of CRC. The methylation status was classified into 3 types: full methylation (FM), partial methylation (PM) and nonmethylation (NM). Only FM closely linked to reduced expression of hMLH1 protein. BRAF mutations were found in 16 cases (11%), all leading to the production of BRAF(V599E). As for MSI status, BRAF mutations were found in 43% of MSI+ and 4% of MSI- cases (p < 0.0001). Among the MSI+ individuals, BRAF mutations were more frequent in cases with hMLH1 deficiency (58%) than those with hMSH2 deficiency (0%; p=0.02). Moreover, they were found in 69% of FM, 4% of PM and 4% of NM, revealing a striking difference between FM and the other 2 groups (FM vs. PM or NM; p < 0.0001). These findings suggest that BRAF activation may participate in the carcinogenesis of sporadic CRCs with hMLH1 hypermethylation in the proximal colon, independently of KRAS activation.