渡部 純

BACKGROUND: The cardiovascular relevance of isolated low levels of high-density lipoprotein cholesterol (HDL-C) is yet to be determined. Stroke often leads to long-term disability, and thus, not only stroke mortality but also stroke incidence is a topic of research. Although isolated low HDL-C level has been found to be a predictor for stroke mortality previously, whether it can predict stroke incidence is unknown. METHODS: In the Jichi Medical School cohort study, 11 025 community-living residents without a history of stroke were examined. Hazard ratios (HRs) for isolated and non-isolated low HDL-C levels were calculated relative to those for normal HDL-C levels in stroke patients using Cox's regression models. RESULTS: During the mean follow-up period of 10.7 years, 412 residents had their first-ever stroke. The multivariable-adjusted HRs for the levels of isolated and non-isolated low HDL-C were 1.11 (95% confidence interval, 0.85-1.44) and 1.35 (1.01-1.81), respectively, when compared to that for normal HDL-C. CONCLUSION: Low HDL-C levels with other dyslipidemias may contribute to the incidence of stroke, not isolated low HDL-C.

Background: Dynamic computed tomography (CT) angiography is useful for evaluating of hepatic vascularity. Although vasodilators increase hepatic blood flow, the utility of dynamic CT with vasodilators is unclear. Here we investigated the utility and safety of dynamic CT with vasodilators. Methods: A prospective case-control radiographic evaluation using abdominal dynamic CT with and without vasodilator was performed at a single center between October 2015 and September 2016. We compared the CT values in Hounsfield units of the aorta; celiac artery; and common, right, and left hepatic arteries in the arterial phase and the main trunk; right and left branches of the portal vein; and right, middle, and left hepatic veins in the portal phase with and without vasodilators. The region of interest was set in each element of the liver vasculature. Four radiological technologists independently and visually compared the scores of the portal vein (P-score) and hepatic vein (V-score) on a 5-point scale with and without vasodilators. Results: The CT values of arteries and veins using vasodilators were significantly higher than those without vasodilators. With and without vasodilators, the P-scores were 3.1 ± 1.2 and 4.0 ± 1.1 (P < 0.05) and the V-scores were 3.3 ± 1.4 and 4.3 ± 1.0 (P < 0.05). Only one patient with vasodilator use had transient hypotension and recovered immediately without medication. Conclusion: Dynamic CT with vasodilators can provides better visualization of vascular structures.

We aimed to investigate the relationship between high-density lipoprotein cholesterol (HDL-C) concentration and the incident stroke subtypes. We enrolled 11 027 participants between the ages of 18 and 90 years without a history of stroke in 12 Japanese communities. Cox's regression models were used for stroke subtypes, adjusted for traditional risk factors, according to the categories based on HDL-C concentrations: 1.04 to 1.55 mmol/L, ≥1.56 mmol/L, and <1.03 mmol/L (as the reference). During a mean follow-up of 10.7 years, 412 stroke events had occurred. However, HDL-C was not significantly associated with the incidence of cerebral infarction and subarachnoid hemorrhage. High HDL-C concentration was associated with a decreased incidence of intracerebral hemorrhage in women (hazard ratio = 0.23; 95% confidence interval = 0.06-0.89), but not in men (hazard ratio = 0.73; 95% confidence interval = 0.27-1.97). Therefore, high HDL-C concentration might have a protective effect on the incidence of intracerebral hemorrhage, particularly in women.

Background: The importance of management of metabolic syndrome (MetS) for risk reduction of cardiovascular disease (CVD) has been recognized worldwide. Because of the comparatively unique characteristics of bodily figure/obesity and incident CVD in Japan, the relevance of MetS on CVD can be still discussed among Japanese people. The present study aimed to review briefly the relationship of MetS with CVD morbidity/mortality among general Japanese people. Methods: Population-based prospective cohort studies evaluating the predictive value of MetS on CVD morbidity/mortality via a PubMed search up to 2019 were summarized. Results: We identified two studies on morbidity that reported MetS to predict CVD morbidity. We identified three studies on mortality, and these studies showed an increased direction of hazard ratio (HR) of CVD mortality, while one study reported an insignificant prediction of MetS for CVD mortality. In the meta-analysis method, MetS significantly predicted CVD morbidity (HR=1.71 [95% confidence interval=1.34-2.18] in men and HR=1.89 [95% confidence interval=1.45-2.46] in women) as well as CVD mortality (HR=1.68 [95% confidence interval=1.37-2.06] in men and HR=1.73 [95% confidence interval=1.39-2.15] in women). Conclusion: Among general Japanese people, MetS can be a positive predictor of CVD morbidity/mortality. Since the studies are limited, more research is needed to establish the findings.

Introduction: Lipoprotein(a) (Lp[a]) is a risk factor of cardiovascular disease (CVD). Familial hypercholesterolemia (FH), which exhibits high low-density lipoprotein cholesterol (LDL-C) levels, is a risk factor of CVD. The relationship of Lp(a) with CVD has been characterized in populations specific to FH. Material and methods: Studies reporting on the relationship of Lp(a) with CVD among FH subjects via PubMed up to 2020 were reviewed. Results: Eight studies were identified as eligible. In the meta-analyses, a high Lp(a) level was significantly and predictively associated with CVD compared to a low Lp(a) level in 2 cross-sectional studies (odds ratio = 2.57; 95% confidence interval (CI): 1.16-5.73) and 6 cohort studies (risk/hazard ratio = 1.91; 95% CI: 1.50-2.43). The totally integrated relative risk of these studies was 1.97 (95% CI: 1.57-2.46). Conclusions: FH subjects with high Lp(a) levels can have a high CVD risk, and besides LDL-C, attention should be paid to Lp(a) levels in FH subjects.

Background: Metabolic syndrome (MetS) and cancer are major public health problems worldwide. The relationship between MetS and cancer death is of great interest. We examined the predictive value of MetS for cancer mortality in Japan. Methods: Study participants included 4495 men and 7028 women aged 18-90 years who were registered between 1992 and 1995 as part of the Jichi Medical School Cohort Study. We used a definition of MetS modified for the Japanese population. The primary outcome was cancer mortality. Additionally, the relationship between MetS and cancer-type specific mortality was examined. Analyses were conducted with Cox's regression models adjusted for age, smoking status, alcohol drinking status, marital status, educational attainment, physical activity, occupational category, and menopausal status (only in women). Results: During a mean follow-up of 18.5 years, 473 men and 297 women died from cancer. MetS was positively associated with cancer mortality in women (hazard ratio [HR], 1.69; 95% confidence interval [CI] 1.21-2.36), but not in men (HR, 1.21; 95% CI 0.90-1.62). Additionally, MetS was associated with a high risk of colorectal (HR, 3.48; 95% CI 1.68-7.22) and breast (HR, 11.90; 95% CI 2.25-62.84) cancer deaths in women. Conclusion: MetS was a significant predictor of cancer mortality in women.

Heparin-induced thrombocytopenia (HIT) is still a relatively uncommon condition and it is not well known how to administer argatroban during continuous hemodiafiltration (CHDF). A 72-year-old man required CHDF with heparin because of the oliguria and hyperpotassemia directly after the open repair of a juxtarenal abdominal aortic aneurysm. As the postoperative blood platelet count dropped and there was a thrombus in the CHDF circuit, HIT was suspected and nafamostat mesilate, but not heparin, was immediately administered for CHDF. As heparin-platelet factor 4 complex was positive, we diagnosed him with HIT and started argatroban while monitoring the activated clotting time (ACT), resulting in no further obstruction of the CHDF and an increase in the platelets. There was no disadvantage for administering nafamostat mesilate which we have commonly used instead of heparin, we should have used argatroban once we suspected HIT. It may be important to consider the history of heparin especially in administering heparin and it may be useful to monitor the ACT when initially starting argatroban for patients with HIT.