Relationship between chronic kidney disease and white matter hyperintensities on magnetic resonance imaging.

Renal dysfunction may be related to cerebral small-vessel disease. This study aimed to assess the relationship between mild renal dysfunction and various white matter hyperintensities on magnetic resonance imaging (MRI). A total of 2106 subjects (1368 men and 738 women; mean age, 56 ± 10 years) without a history of stroke were enrolled in the study. Kidney function was evaluated in terms of estimated glomerular filtration rate (eGFR), calculated using the relationship 194Cr(-1.094) × age(-0.287) × 0.739 (if female), where Cr is serum creatinine concentration. White matter hyperintensity on T2-weighted MRI was classified as deep and/or subcortical white matter hyperintensity (DSWMH), periventricular hyperintensity (PVH), or asymptomatic cerebral infarction (ACI). The prevalence of ACI, DSWMH, and PVH was significantly correlated with degree of eGFR reduction; in the subgroups with eGFR ≥ 90, 60∼89, and <60 mL/min/1.73 m(2), the following prevalences were found: ACI, 7%, 6%, and 16%; DSWMH, 18%, 21%, and 37%; PVH: 7%, 10%, and 21%. The odds ratios for ACI, DSWMH, and PVH of eGFR <60 mL/min/1.73 m(2) were significantly increased, to 2.11 (95% confidence interval [CI], 1.23-3.61; P = .006), 2.26 (1.53-3.34; P < .001), and 2.81 (1.67-4.72; P < .001), respectively. Our data indicate that mild renal dysfunction may be associated with an increase in cerebral small-vessel disease independent of hypertension.

Chronic kidney disease in patients with ischemic stroke.

To examine the significance of renal dysfunction in patients who have sustained ischemic stroke, we examined the relationship between the renal function evaluated in terms of estimated glomerular filtration rate (eGFR) and the subtype of brain infarction (BI) in patients with ischemic stroke. A total of 639 patients with BI were enrolled in this study, with 314 subjects without stroke or transient ischemic attack registered as age-matched controls. eGFR was calculated according to the equation 194 × Cr(-1.094) × Age(-0.287) (-0.739 if female), where Cr is serum creatinine concentration, and was classified into four stages: stage I, eGFR ≥ 90 mL/min/1.73 m(2); stage II, eGFR 60 ~ 89 mL/min/1.73 m(2); stage III, eGFR 30 ~ 59 mL/min/1.73 m(2); and stage IV, eGFR <29 mL/min/1.73 m(2). Stage III-IV was significantly more prevalent in the BI group (38%) than in the control group (22%; P < .001). The odds ratio for stage III-IV was significantly higher in the BI group (1.93; 95% confidence interval [CI], 1.35-2.76). Among the BI subgroups, the odds ratios of stage III-IV for the atherothrombotic type (1.81; 95% CI, 1.23-2.68) and the cardiogenic type (2.25; 95% CI, 1.32-3.83) were significantly higher than that of the control group, but that of stage III-IV for lacunar type was not (1.67; 95% CI, 0.98-2.84). Our results indicate that ischemic stroke is frequently associated with renal dysfunction. Chronic kidney disease might be independent risk factor for infarction, especially for cardiogenic and atherosclerotic types.

The role of high-sensitivity C-reactive protein in asymptomatic intra- and extracranial large artery diseases.

BACKGROUND: It remains unclear whether high-sensitivity CRP (hs-CRP) is predictive of atherosclerosis in the intracranial artery. The aim of this study is to assess the role of hs-CRP in asymptomatic intracranial artery occlusive diseases. METHODS: Of the 3,366 apparently healthy subjects who received a brain checkup, 138 with > or =25% intracranial artery stenosis on magnetic resonance angiography, 267 with > or =25% extracranial carotid artery stenosis on B-mode ultrasonography and 435 without intracranial artery or extracranial carotid artery stenosis (age-matched controls) were selected for this study. RESULTS: The mean CRP concentration in the subjects with intracranial artery stenosis was not significantly different from that in the control subjects, and the differences of mean CRP concentrations among the subgroups with 25-49, 50-74 and 75% or greater stenosis in the intracranial artery were not significant. The odds ratios of hs-CRP for extracranial carotid artery stenosis tended to increase with increasing CRP concentrations, but those of hs-CRP for intracranial artery stenosis showed no significant difference. CONCLUSION: The degree of atherogenic inflammation in asymptomatic intracranial artery stenosis may be less than that in extracranial carotid artery stenosis.

[Cancer screening with PET: advantages and limitations].

Warburg first reported that tumours are characterized by abnormally increased glucose metabolism accompanied by increase production of lactate. This is a basic principle underlying cancer detection by the glucose analogue 18-F-fluoro-2-deoxy-D-glucose (FDG). FDG positron emission tomography (PET) is currently used widely to examine virtually any part of the body in order to detect tumours, e.g., lung, breast, colorectal, pancreatic and head and neck cancers, malignant lymphoma and malignant melanoma. The advantage of whole-body FDG-PET in comparison with the other imaging modalities is that it allows the entire body to be surveyed seamlessly within a reasonably short period. Furthermore, the staging of most cancers can be determined. The characteristics of whole-body FDG-PET seem to satisfy the requirements for cancer screening. PET used simultaneously with conventional tests can prevent the overlooking of cancer, reduce false-positive results and assist in the interpretation of CT and MRI images. Thus, PET can play a supportive role when used with conventional screening tests. In 1994, PET was applied to cancer screening for the first time at our Imaging Center at Lake Yamanaka in Japan. Within 12 years after starting, a total of 10,292 asymptomatic individuals (6,227 men and 4,065 women; mean age, 52.2 and 52.9 years) participated in 29,090 screening sessions. As a result, malignant tumours were demonstrated in 355 of the 10,292 participants (2.61%). PET findings were true-positive in 175 of the 355 cancers (49.3%).

Individualized total cavopulmonary connection technique for patients with asplenia syndrome.

BACKGROUND: Outcomes after univentricular repair for patients with asplenia syndrome remain unsatisfactory, not only because of clinical difficulties in patient selection, but also secondary to technical difficulties in the separation of the systemic and pulmonary circulations, particularly with the rerouting technique for the inferior systemic veins. METHODS: Between February 1995 and May 2000, a total of 14 consecutive patients with asplenia syndrome underwent bidirectional cavopulmonary connection with obliteration of additional pulmonary blood flow, followed by a total cavopulmonary connection. The rerouting technique for inferior systemic venous blood flow was individualized to optimize laminar nonturbulent flow characteristics in the pathway, and to minimize prosthetic load and suture load on the atrial wall. The lateral tunnel or tube conduit technique was used in an extraatrial, intra-extraatrial, or intraatrial fashion. No fenestration was applied. RESULTS: No hospital mortality was observed. Systemic venous flow was evaluated using magnetic resonance angiography, revealing no signs of obstruction, turbulence, or stasis either in or near the reconstructed pathways, irrespective of the rerouting technique. Postoperative catheterization revealed favorable hemodynamics including an inferior vena cava pressure of 13 +/- 2 mm Hg and arterial oxygen saturation of 93.4% +/- 3.5% at room air. All patients have remained free of symptoms, although 1 patient died of acute septic complications 3.5 years after the procedure. CONCLUSIONS: The complexity of cardiac anomalies in asplenia syndrome warrants individualization of the total cavopulmonary connection technique used in reconstruction of the inferior systemic venous pathway. Optimizing flow characteristics in the pathway should be a priority. A staging approach allows suitable selection of candidates for univentricular repair.

Cardioscopic guidance of linear lesion creation for radiofrequency ablation.

BACKGROUND: The broad use of catheter ablation of atrial fibrillation is limited by the difficulty inherent in creating transmural linear lesions under fluoroscopy. Therefore, we evaluated cardioscopy as a more accurate method of guiding the catheter for the placement of linear lesions. METHODS: Nineteen swine underwent endocardial ablation to create linear conduction block lesions in the right atrium under cardioscopy (group I, n = 13) or fluoroscopy (group II, n = 6). In both groups, the linear lesion was created between the superior and inferior vena cava, perpendicular to hexapolar electrodes placed on the epicardial surface. Each swine received two pairs of epicardial hexapolar electrodes: one pair to measure the conduction delay time across the ablated line and another pair for pacing. The time spent to complete the ablation, number of trials and effective ablations, ratio of effective ablations to trials, length of the lesion, conduction delay under pacing, and postmortem pathology were compared between the two groups. RESULTS: Statistically significant differences were found for the time required for ablation, ratio of effective ablation to total number of trials, and conduction delay. Histologic analysis revealed more homogenous, continuous lesions in group I. CONCLUSIONS: Cardioscopy facilitated the placement of a conduction block line more efficiently than ablation performed under fluoroscopy. Landmarks of tissue relevant to ablation are readily visualized by cardioscopy. Moreover, cardioscopy can be useful for the development of a guiding catheter for the ablation of atrial fibrillation.

A Ferrofluidic Seal Specially Designed for Rotary Blood Pumps.

One of the key technologies required for rotary blood pumps is sealing of the motor shaft. A ferrofluidic seal was developed for an axial flow pump. The seal body was composed of a plastic magnet and two pole pieces. This seal was formed by injecting ferrofluid into the gap between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was provided on the pole piece. Sealing pressure of the seal was measured. The sealing pressure was maintained at more than 23.3 kPa (175 mm Hg) for a motor speed up to 11,000 rpm. The specially designed ferrofluidic seal for sealing out liquids is useful for axial flow blood pumps.

Effect of post-ischemic hypothermia on spinal cord damage induced by transient ischemic insult in rabbits.

OBJECTIVE: The effect of post-ischemic mild hypothermia applied immediately after induced transient ischemia on the extent of neuronal damage to the spinal cord was investigated in rabbit. SUBJECTS AND METHODS: A 15-minute period of transient abdominal aortic occlusion for spinal cord ischemia at a rectal temperature of 37.3 +/- 0.3 degrees C was performed just below the left renal vein via median laparotomy. Three groups of rabbits were investigated; Group 1 (n = 8) subjected to ischemia and reperfused at the same temperature for 7 hours, Group 2 (n = 8) also subjected to ischemia and then to 6 hours of systemic hypothermia (32.5 +/- 0.5 degrees C), and Group 3 (n = 8) non-ischemic controls. All the rabbits in Group 1 and Group 2 were sacrificed at 1 week after ischemic injury. Spinal cord sections were examined microscopically to determine the extent of ischemic neuronal damage. RESULTS: The mean modified Tarlov's score at 1 week after ischemic injury was 0.5 +/- 0.8 in Group 1, whereas it was 4.4 +/- 1.4 (p < .001) in Group 2. The mean total number of surviving neurons within examined sections of the spinal cord was significantly greater in Group 2 than in Group 1 (Group 1: 81 +/- 66.1 vs Group 2: 300.9 +/- 154.1, p < .001). CONCLUSION: Post-ischemic hypothermia induced immediately after reperfusion significantly reduced ischemia-induced neuronal damage in rabbit.

Significance of the presence of metabolic syndrome in patients with asymptomatic arteriosclerosis affecting the aorta and the cerebral, extra-cranial carotid and coronary arteries.

OBJECTIVE: The presence of metabolic syndrome (MetS) is strongly associated with stroke and cardiovascular diseases. However, the relationship between MetS and the localization of atherosclerosis at various sites remains uncertain. In this study, in order to reveal the relevance of MetS to atherosclerosis at several sites, we investigated the relationships among vascular risk factors, asymptomatic cerebral infarction and atherosclerosis in the aorta and carotid and coronary arteries in adults without overtly symptomatic cerebrovascular or cardiovascular disease. METHODS: The subjects in this study included 2,759 Japanese participants (1,845 men and 914 women, mean age: 52 years) with no history of stroke or cardiovascular events. The diagnosis of MetS was made based on modifications to criteria obtained from the National Cholesterol Education Program Adult Treatment Panel. In all subjects, the presence of cerebral infarction in the extra-cranial carotid, coronary and aortic arteries was investigated using MRI, B-mode ultrasonography and CT. RESULTS: Of the 2,759 subjects, 796 (28.9%) fulfilled the criteria for MetS. The presence of MetS increased the odds ratio (OR) to 1.89 (95% confidence interval (CI): 1.35-2.65, p-value <0.0001) for asymptomatic cerebral infarction, 1.70 (95% CI: 1.37-2.10, p-value <0.0001) for carotid arteriosclerosis, 2.07 (95% CI: 1.62-2.27, p-value <0.0001) for coronary calcification and 1.67 (95% CI: 1.33-2.09, p-value<0.0001) for aortic calcification. CONCLUSION: The presence of MetS was found to be significantly correlated with arteriosclerosis in all regions, including the cerebral small-vessels, extra-cranial carotid arteries, coronary arteries and abdominal aorta. MetS might be a predictor for small and large vessel disease throughout the body.

Is mild renal dysfunction a risk factor for carotid atherosclerosis in apparently healthy adults?

OBJECTIVE: Renal dysfunction may be related to cerebrovascular disease. The aim of this study was to assess the relationship between mild renal dysfunction and carotid artery atherosclerosis detected by ultrasonography in apparently healthy subjects. METHODS: A total of 2,106 persons (1,368 men and 738 women, mean age+/-S.D.: 56 +/- 10 years) with no history of stroke were enrolled. Kidney function was evaluated in terms of estimated glomerular filtration rate (eGFR), calculated by using the relationship 194Cr(-1.094)×Age(-0.287)×0.739 (if female), where Cr is serum creatinine concentration. Atherosclerosis on ultrasonography was defined as regional intimal thickening or nodular lesion. RESULTS: Atherosclerotic lesions were significantly more frequent in subjects with CKD stage 3 than in CKD stage 1 or 2 (p<0.001). Odds ratios for atherosclerotic lesions were significantly increased to 1.11 (95% confidence interval: 1.09-1.12, p<0.001) for increasing age, 1.66 (1.31-2.10, p<0.001) for male sex, 1.76 (1.43-2.16, p<0.001) for systolic blood pressure ≥130 mmHg and/or diastolic blood pressure ≥85 mmHg, 1.61 (1.28-2.01, p<0.001) for LDL-cholesterol ≥140 mg/dL, and 1.59 (1.23-2.05, p=0.003) for smoking habit versus no risk factor. The odds ratio of CKD stage 3 for ≥50% carotid artery stenosis was significantly increased to 3.47 (1.09-11.08, p=0.035), although CKD stage 2 and stage 3 were not significant (0.77, 95% CI: 0.59-1.01, p=0.068; 0.99, 95%CI: 0.67-1.46, p=0.981, respectively). CONCLUSION: Renal dysfunction defined in terms of eGFR might be associated with early-stage carotid atherosclerosis, but traditional vascular risk factors, including increasing age or hypertension, appear to play a major role.

The significance of multiple risk factors for early carotid atherosclerosis in Japanese subjects.

OBJECTIVE: The aim of this study was to assess the significance of multiple risk factors for early carotid atherosclerosis in the Japanese population. METHODS: The relation between traditional vascular risk factors and serum high-sensitivity CRP (hs-CRP) or atherosclerotic lesions in the carotid arteries detected by B-mode ultrasonography was evaluated. PATIENTS: The subjects were 1,880 persons (1,240 men and 640 women, mean age 55+/-10 years old) without ischemic stroke, infection or collagen diseases. RESULTS: In the men, the odds ratio (OR) for atherosclerotic lesion was increased at 1.90 (95% CI: 1.05-3.43, P=0.032) in those with one risk factor, 2.42 (1.36-4.32, P=0.002) in those with two, and 2.95 (1.69-5.16, P<0.001) in those with three or more. In the women, the OR was similarly increased 1.93 (95% CI: 1.04-3.56, P=0.035) for one risk factor, 2.31 (1.23-4.33, P=0.009) for two, and 3.52 (1.80-6.87, P<0.001) for three or more. The mean hs-CRP concentration increased significantly with the increasing number of risk factors (men and women, P<0.001) and with the degree of carotid arterial stenosis (men, P=0.011; women, P=0.008). CONCLUSION: Multiple risk factors are more predictive than a single risk factor for early carotid atherosclerosis in the Japanese population.

Computational fluid dynamics analysis of an intra-cardiac axial flow pump.

A low rate of hemolysis is an important factor for the development of a rotary blood pump. It is, however, difficult to identify the areas where hemolysis occurs. Computational fluid dynamics (CFD) analysis enables the engineer to predict hemolysis on a computer. In this study, fluid dynamics throughout intracardiac axial flow pumps with different designs were analyzed three-dimensionally using CFD software. The computed pressure-flow characteristics of the pump were in good agreement with the measurements. The Reynolds shear stress was computed along particle trace lines. Hemolysis was estimated on the basis of shear stress (tau) and its exposure time (Deltat): dHb/Hb = 3.62 x 10(-7)(tau)(i)(2.416) x Delta(t)(i)(0.785). Particle damage increased with time along the particle trace lines. Hemolysis of each of the pumps was measured in vitro. The computed hemolysis values were in good agreement with the experimental results. CFD is a useful tool for developing a rotary blood pump.