Yuji Nishizaki

Significance of imbalance in the ratio of serum n-3 to n-6 polyunsaturated fatty acids in patients with acute coronary syndrome.

This study aimed to assess the balance of serum n-3 to n-6 polyunsaturated fatty acids (PUFAs) in patients with acute coronary syndrome (ACS). We enrolled 1,119 patients who were treated and in whom serum PUFA level was evaluated in 5 divisions of cardiology in a metropolitan area in Japan. Serum levels of PUFAs, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA), were compared between patients with and without ACS. We also evaluated the balance of serum n-3 to n-6 PUFAs, including EPA/AA and DHA/AA ratios. EPA/AA values were 0.46 ± 0.32 and 0.50 ± 0.32 in the ACS and non-ACS groups, respectively. DHA/AA values were 0.95 ± 0.37 and 0.96 ± 0.41 in the ACS and non-ACS groups, respectively. Next, we divided the patients into 3 groups based on the tertiles of EPA/AA or tertiles of DHA/AA to determine the independent risk factors for ACS. According to multivariate logistic regression analysis, the group with the lowest EPA/AA (≤0.33) had a greater probability of ACS (odds ratio 3.14, 95% confidence interval 1.16 to 8.49), but this was not true for DHA/AA. In conclusion, an imbalance in the ratio of serum EPA to AA, but not in the ratio of DHA to AA, was significantly associated with ACS.

The hospital educational environment and performance of residents in the General Medicine In-Training Examination: a multicenter study in Japan.

Background It is believed that the type of educational environment in teaching hospitals may affect the performance of medical knowledge base among residents, but this has not yet been proven. Objective We aimed to investigate the association between the hospital educational environment and the performance of the medical knowledge base among resident physicians in Japanese teaching hospitals. Methods To assess the knowledge base of medicine, we conducted the General Medicine InTraining Examination (GM-ITE) for second-year residents in the last month of their residency. The items of the exam were developed based on the outcomes designated by the Japanese Ministry of Health, Labor, and Welfare. The educational environment was evaluated using the Postgraduate Hospital Educational Environment Measure (PHEEM) score, which was assessed by a mailed survey 2 years prior to the exam. A mixed-effects linear regression model was employed for the analysis of variables associated with a higher score. Results Twenty-one teaching hospitals participated in the study and a total of 206 residents (67 women) participated and completed the exam. There were no residents who declined to participate in the exam. The mean GM-ITE score was 58 (standard deviation 8.4). The mixed-effects linear regression analysis showed that a higher PHEEM score was associated with a higher GM-ITE score (P = 0.02). Having a department of general medicine, and hospital location in a provincial community (versus an urban setting), were also shown to have a significant relationship with the higher score (P = 0.03, and P = 0.02, respectively). Conclusion We found that the performance of the medical knowledge base of resident physicians was significantly associated with the educational environment of their hospitals. Improvement of the educational environment in teaching hospitals might be crucial for enhancing the performance of resident physicians in Japan.

Long-term coronary arterial response to biodegradable polymer biolimus-eluting stents in comparison with durable polymer sirolimus-eluting stents and bare-metal stents: Five-year follow-up optical coherence tomography study

OBJECTIVE The long-term coronary arterial response of biodegradable polymer biolimus-eluting stents (BES) remains unclear. We sought to evaluate the coronary arterial response of biodegradable polymer BES at 5 years after stent implantation using optical coherence tomography (OCT) as compared with that of durable polymer sirolimus-eluting stents (SES) and bare-metal stents (BMS). METHODS Five-year follow-up OCT was performed in 30 patients with 33 stents (10 with 12 BES; 10 with 11 SES; 10 with 10 BMS). Quantitative parameters and qualitative characteristics of the neointima were evaluated. A total of 5178 struts (BES, n = 2056; SES, n = 1410; BMS, n = 1712) were analyzed. RESULTS Uncovered struts were found in 15 out of 2055 struts in the BES (weighted estimate 0.01%, 95% confidence intervals [CI]: 0.00-0.33%) and 54 out of 1410 struts in the SES (0.11%, 95% CI: 0.00-3.33%) (odds ratio [OR] 0.12, 95% CI: 0.01-1.95, p = 0.13). None of 1712 struts were uncovered in the BMS. Cross-sectional qualitative analysis of neointimal tissue showed that the frequency of lipid-laden neointima tended to be lower in the BES (2.26%, 95% CI: 0.38-12.3%) compared with the SES (9.90%, 95% CI: 4.37-20.9%; OR 0.21, 95% CI 0.03-1.16, p = 0.07), and was similar to the BMS (2.23%, 95% CI: 0.54-8.74%; OR 0.98, 95% CI 0.13-7.14, p = 0.98). CONCLUSIONS Biodegradable polymer BES shows a favorable coronary arterial response compared with SES, but different response with BMS at 5 years follow-up. The observed frequency of in-stent neoatherosclerosis within BES was similar to BMS and tended to be lower than SES.

Japan’s initiative on rare and undiagnosed diseases (IRUD): towards an end to the diagnostic odyssey

Japan has been facing challenges relating to specifically defined rare diseases, called Nan-Byo in Japanese (literally ‘difficult’+‘illness’), and has already taken measures for them since 1972. This governmental support has surely benefited Nan-Byo patients; however, those suffering from medically unidentified conditions do not fall into this scheme and thus still confront difficulty in obtaining an examination, a diagnosis, and a treatment. To identify such rare and often undiagnosed diseases, we must integrate systematic diagnosis by medical experts with phenotypic and genetic data matching. Thus, in collaboration with Nan-Byo researchers and the Japanese universal healthcare system, the Japan Agency for Medical Research and Development launched the Initiative on Rare and Undiagnosed Diseases (IRUD) in 2015. IRUD is an ambitious challenge to construct a comprehensive medical network and an internationally compatible data-sharing framework. Synergizing with existing next-generation sequencing capabilities and other infrastructure, the nationwide medical research consortium has successfully grown to accept more than 2000 undiagnosed registrants by December 2016. We also aim at expanding the concept of microattribution throughout the initiative; that is, proper credit as collaborators shall be given to local primary care physicians, nurses and paramedics, patients, their family members, and those supporting the affected individuals whenever appropriate. As it shares many challenges among similar global efforts, IRUD’s future successes and lessons learned will significantly contribute to ongoing international endeavors, involving players in basic research, applied research, and societal implementation.

Additional value of the red blood cell distribution width to the Mehran risk score for predicting contrast-induced acute kidney injury in patients with ST-elevation acute myocardial infarction

BACKGROUND Contrast-induced acute kidney injury (CI-AKI) after percutaneous coronary intervention in patients with ST-elevation myocardial infarction (STEMI) is a common complication associated with worse outcome. Considering the prognostic predictive value of the red cell distribution width (RDW), we aimed to measure the usefulness of RDW for predicting CI-AKI. METHODS All consecutive STEMI patients without hemodialysis from June 2011 to September 2013 admitted to St. Lukes International Hospital were enrolled. We performed primary percutaneous coronary intervention in all patients. CI-AKI was defined as a >25% increase or an absolute increase in serum creatinine of 0.5mg/dl within 3 days after percutaneous coronary intervention. The potential additional predictive value of RDW with the Mehran risk score (MRS) on admission was estimated. RESULTS A total of 102 patients (78.4% males) were analyzed - 10 of the 102 (10%) STEMI patients developed CI-AKI. Multivariate analysis showed that RDW was an independent variable predicting CI-AKI in these patients [odds ratio, 2.029; 95% confidence interval (95% CI), 1.029-3.999; p=0.041]. The areas under the receiver operating characteristic curves for MRS only, RDW only, and the combined model (MRS and RDW) for the prediction of CI-AKI were 0.806 (95% CI, 0.696-0.917), 0.719 (95% CI, 0.536-0.902), and 0.846 (95% CI, 0.744-0.949), respectively. CONCLUSION We showed the potential predictive ability of RDW, only if used with MRS, for CI-AKI in STEMI patients. Further evaluation of RDW for predicting CI-AKI in patients with STEMI is needed.

Development of new risk score for pre-test probability of obstructive coronary artery disease based on coronary CT angiography

Existing methods to calculate pre-test probability of obstructive coronary artery disease (CAD) have been established using selected high-risk patients who were referred to conventional coronary angiography. The purpose of this study is to develop and validate our new method for pre-test probability of obstructive CAD using patients who underwent coronary CT angiography (CTA), which could be applicable to a wider range of patient population. Using consecutive 4137 patients with suspected CAD who underwent coronary CTA at our institution, a multivariate logistic regression model including clinical factors as covariates calculated the pre-test probability (K-score) of obstructive CAD determined by coronary CTA. The K-score was compared with the Duke clinical score using the area under the curve (AUC) for the receiver-operating characteristic curve. External validation was performed by an independent sample of 319 patients. The final model included eight significant predictors: age, gender, coronary risk factor (hypertension, diabetes mellitus, dyslipidemia, smoking), history of cerebral infarction, and chest symptom. The AUC of the K-score was significantly greater than that of the Duke clinical score for both derivation (0.736 vs. 0.699) and validation (0.714 vs. 0.688) data sets. Among patients who underwent coronary CTA, newly developed K-score had better pre-test prediction ability of obstructive CAD compared to Duke clinical score in Japanese population.

Relationship between nursing workloads and patient safety incidents

Objective: To evaluate the relationship between nursing workloads and patient safety incidents in inpatient wards of a general hospital. Methods: A retrospective data analysis was conducted involving the internal medicine wards in a teaching hospital in Japan between July 1st and December 31st, 2006. To assess associations between nursing workloads and patient safety incidents, we analyzed the following: the relationships between the level of patients’ dependency and the number of incident reports; and the relationships between the presence of accidental falls and the presence of patients transferred from the intensive care unit to the wards. Results: Fifty-five nurses worked on the wards (105 beds). The total number of incidents was 142 over the 184 days of this study. There was a positive trend between the number of incidents and the total patient dependency score. The presence of accidental falls in the wards was associated with the presence of transfers from the intensive care unit to the wards (odds ratio 3.14, 95% confidence interval: 1.48, 6.65). Conclusion: Greater nursing workloads may be related to the higher number of patient safety incidents in inpatient wards of hospitals.

Incremental prognostic value of coronary computed tomographic angiography high-risk plaque characteristics in newly symptomatic patients

BACKGROUND The incremental prognostic value of the plaque features in coronary computed tomographic angiography (CTA) has not been well assessed. This study was designed to determine whether CTA high-risk plaques have prognostic value incremental to the Framingham risk score (FRS) and the severity of luminal obstruction. METHODS A total of 628 newly symptomatic patients without known coronary artery disease underwent CTA. They were followed for a median of 677 days during which there were 26 cardiac events, including cardiac death, acute myocardial infarction, and hospitalization for unstable angina. Incremental prognostic value of adding plaque characteristics to the number of diseased vessels and the FRS was evaluated using 3 Cox models and net reclassification indexes. RESULTS The discrimination index was significantly increased by adding the number of diseased vessels to the FRS (change in c-statistic from 65.8% to 78.6%, p=0.028) but not significantly by further adding plaque characteristics (change in c-statistic from 78.6% to 80.0%, p=0.812). However, improved model-fitting by adding plaque characteristics into the linear combination with risk score and the number of diseased vessels (p=0.007 from likelihood ratio test) and the lowest value of Akaikes information criteria of that model indicated that plaque characteristics improved both predictive accuracy and discrimination perspective. More subjects reclassified by plaque characteristics were moved to directions consistent with their subsequent cardiac event status than in an inconsistent direction. CONCLUSIONS Evaluation of CTA plaque characteristics may provide incremental prognostic value to the number of diseased vessels and the FRS.

Impact of inpatient caseload, emergency department duties, and online learning resource on General Medicine In-Training Examination scores in Japan

Background Both clinical workload and access to learning resource are important components of educational environment and may have effects on clinical knowledge of residents. Methods We conducted a survey with a clinical knowledge evaluation involving postgraduate year (PGY)-1 and -2 resident physicians at teaching hospitals offering 2-year postgraduate training programs required for residents in Japan, using the General Medicine In-Training Examination (GM-ITE). An individual-level analysis was conducted to examine the impact of the number of assigned patients and emergency department (ED) duty on the residents’ GM-ITE scores by fitting a multivariable generalized estimating equations. In hospital-level analysis, we evaluated the relationship between for the number of UpToDate reviews for each hospital and for the hospitals’ mean GM-ITE score. Results A total of 431 PGY-1 and 618 PGY-2 residents participated. Residents with four or five times per month of the ED duties exhibited the highest mean scores compared to those with greater or fewer ED duties. Those with largest number of inpatients in charge exhibited the highest mean scores compared to the residents with fewer inpatients in charge. Hospitals with the greater UpToDate topic viewing showed significantly greater mean score. Conclusion Appropriate ED workload and inpatient caseload, as well as use of evidence-based electronic resources, were associated with greater clinical knowledge of residents.

Impact of the augmentation time ratio on direct measurement of central aortic pressure in the presence of coronary artery disease.

The augmentation index measured by using the central artery pressure is associated with an increased risk of coronary artery disease (CAD). However, no study has examined the role of the time duration of the central artery pressure on CAD. Therefore, we evaluated the relationship between the central blood pressure time duration and the presence of CAD. All patients without a history of revascularization or prior myocardial infarction who underwent an elective coronary angiography at one of the two hospitals from January to September 2013 were analyzed. CAD was defined as a significant stenosis in one of the main coronary branches. The augmentation time ratio was defined as the ratio of the reflection to peak systolic time T2T1 duration divided by the peak systolic time to aortic notch T3T2 duration. We analyzed the relationship between the central pressure waveform (not only augmentation pressure) and the presence of CAD. A total of 146 (57.3%) out of 255 patients had a significant CAD. T2T1 duration was longer in the CAD group than the no CAD group, and the T3T2 duration was shorter in the CAD group than the no CAD group. The augmentation time ratio (T2T1/T3T2) was significantly larger in the CAD group than in the no CAD group. The augmentation index and augmentation pressure were lower in the no CAD group, but this difference was not statistically significant. The augmentation time ratio was an independent factor related to no CAD, especially in patients with a high augmentation index (odds ratio, 2.17; 95% confidence interval, 1.02–4.63). The augmentation time ratio was an independent factor related to the presence of CAD.