Hiroaki Miyata

The University of Tokyo, Tōkyō, Japan

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Publications (74)225.75 Total impact

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    ABSTRACT: Postoperative atrial fibrillation (POAF) increases considerably the chances of morbidity and mortality after cardiac surgery. The objective of this study was to identify the major risk factors responsible for POAF after thoracic aortic surgery in order to define preventive measures. We analyzed 12,260 records (between January 1, 2004, and December 31, 2008) obtained from the Japan Adult Cardiovascular Surgery Database. Patients with history of AF were excluded. Data were collected for 12 preoperative and 10 operative risk factors that had been proven or believed to influence POAF. The relationship between the risk factors and outcome was assessed by the Fisher exact test, Student t test, and multiple logistic regression analysis. The patients' mean age (± standard deviation) was 67.5 ± 12.7 years, and 27% of the subjects were women. The incidence of POAF was 17.1%. The following risk factors were associated with increased POAF: age (p < 0.0001), history of smoking (p < = 0.020), hypertension (p = 0.020), congestive heart failure (p < 0.0001), urgent operation (p = 0.023), and concomitant with nonelective coronary artery bypass (p = 0.022). Postoperative mortality and postoperative stroke were significantly increased in patients with POAF (p < 0.0001 in both cases). The odds ratios for the POAF risk factors were as follows: replacement of the ascending aorta, 1.67; aortic arch, 1.62; aortic root, 1.42; concomitant with valve operation, 1.35; age, 1.27; and urgent operation, 1.22. Several risk factors contribute to the incidence of POAF after thoracic aortic surgery. We found that POAF significantly increased 30-day operative mortality (p < 0.0001). Our findings can be used to develop a risk stratification system for the prediction of POAF. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
    The Annals of Thoracic Surgery 11/2014; · 3.63 Impact Factor
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    ABSTRACT: The cancer registry is an essential part of any rational program of evidence-based cancer control. The cancer control program is required to strategize in a systematic and impartial manner and efficiently utilize limited resources. In Japan, the National Clinical Database (NCD) was launched in 2010. It is a nationwide prospective registry linked to various types of board certification systems regarding surgery. The NCD is a nationally validated database using web-based data collection software; it is risk adjusted and outcome based to improve the quality of surgical care. The NCD generalizes site-specific cancer registries by taking advantage of their excellent organizing ability. Some site-specific cancer registries, including pancreatic, breast, and liver cancer registries have already been combined with the NCD. Cooperation between the NCD and site-specific cancer registries can establish a valuable platform to develop a cancer care plan in Japan. Furthermore, the prognosis information of cancer patients arranged using population-based and hospital-based cancer registries can help in efficient data accumulation on the NCD. International collaboration between Japan and the USA has recently started and is expected to provide global benchmarking and to allow a valuable comparison of cancer treatment practices between countries using nationwide cancer registries in the future. Clinical research and evidence-based policy recommendation based on accurate data from the nationwide database may positively impact the public.
    International Journal of Clinical Oncology 11/2014; 20(1). · 2.17 Impact Factor
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    ABSTRACT: The Japan Cardiovascular Surgery Database (JCVSD) is a nationwide benchmarking project to improve the quality of cardiovascular surgery in Japan. This study aimed to develop new JACVD risk models not only for operative mortality but also for each postoperative complication for coronary artery bypass grafting (CABG) operations, valve operations, and thoracic aortic operations. We analyzed 24,704 isolated CABG operations, 26,137 valve operations, and 18,228 thoracic aortic operations. Risk models were developed for each operation for operative death, permanent stroke, renal failure, prolonged ventilation (>24 hours), deep sternal wound infection, and reoperation for bleeding. The population was divided into an 80% development sample and a 20% validation sample. The statistical model was constructed by multiple logistic regression analysis. Model discrimination was tested using the area under the receiver operating characteristic curve (C index). The 30-day mortality rates for isolated CABG, valve, and thoracic aortic operations were 1.5%, 2.5%, and 6.0%, respectively, and operative mortality rates were 2.4%, 3.8%, and 8.4%, respectively. The C indices for the end points of isolated CABG, valve, and aortic thoracic operations were 0.6358 for (deep sternal infection) to 0.8655 (operative mortality), 0.6114 (reoperation for bleeding) to 0.8319 (operative death), and 0.6311 (gastrointestinal complication) to 0.7591 (operative death), respectively. These risk models increased the discriminatory power of former models. Thus, our models can be said to reflect the current state of Japan. With respect to major complications, useful feedback can now be provided through the Japan Cardiovascular Surgery Database Web-based system. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.
    The Annals of Thoracic Surgery 11/2014; · 3.63 Impact Factor
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    ABSTRACT: The purpose of this study was to develop risk models for congenital heart surgery short-term and midterm outcomes from a nationwide integrated database drawn from hospitals in Japan. The Japan Congenital Cardiovascular Surgery Database collects clinical information from institutions throughout Japan specializing in congenital heart surgery. Variables and definitions used in the Japan Congenital Cardiovascular Surgery Database are almost identical to those of the Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery database for congenital heart surgery. We used logistic regression to develop risk models, which were then validated through spilt-sample validation. In addition to procedural complexity categories by Risk Adjustment in Congenital Heart Surgery (RACHS-1) score, we incorporated patient characteristics to predict surgical outcome. Among 8923 congenital heart operations performed at 69 sites with cardiac surgical programs, 30-day mortalities by RACHS-1 category were as follows: I, 0.1% (n = 1319); II, 0.5% (n = 3211); III, 2.2% (n = 3285); IV, 4.3% (n = 818); and V and VI, 8.6% (n = 290). From the test data set (n = 7223), we developed 3 risk models (30-day mortality, 90-day mortality, and 90-day and in-hospital mortality) with 11 variables, including age category, RACHS-1 category, preoperative risk factors, number of surgical procedures, unplanned reoperations, status of surgery, surgery type, asplenia, and prematurity (<35 weeks). For the performance metrics of the risk models, C statistic values of 30-day, 90-day, and 90-day and in-hospital mortalities for the test data set were 0.85, 0.85, and 0.84, respectively. When only the RACHS-1 score was used for discrimination, the C statistic values of 30-day, 90-day, and 90-day and in-hospital mortalities for the validation data set were 0.73, 0.73, and 0.77, respectively. The proposed risk scores and categories have high discrimination power for predicting mortality, demonstrating improvement relative to existing consensus-based methods. Risk models incorporating these measures may be useful for comparing mortality outcomes cross institutions or countries with mixed cases. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
    Journal of Thoracic and Cardiovascular Surgery 11/2014; 148(5):2201-6. · 3.99 Impact Factor
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    ABSTRACT: The JCVSD (Japan Cardiovascular Surgery Database) was organized in 2000 to improve the quality of cardiovascular surgery in Japan. Web-based data harvesting on adult cardiac surgery was started (Japan Adult Cardiovascular Surgery Database, JACVSD) in 2001, and on congenital heart surgery (Japan Congenital Cardiovascular Surgery Database, JCCVSD) in 2008. Both databases grew to become national databases by the end of 2013. This was influenced by the success of the Society for Thoracic Surgeons' National Database, which contains comparable input items. In 2011, the Japanese Board of Cardiovascular Surgery announced that the JACVSD and JCCVSD data are to be used for board certification, which improved the quality of the first paperless and web-based board certification review undertaken in 2013. These changes led to a further step. In 2011, the National Clinical Database (NCD) was organized to investigate the feasibility of clinical databases in other medical fields, especially surgery. In the NCD, the board certification system of the Japan Surgical Society, the basic association of surgery was set as the first level in the hierarchy of specialties, and nine associations and six board certification systems were set at the second level as subspecialties. The NCD grew rapidly, and now covers 95% of total surgical procedures. The participating associations will release or have released risk models, and studies that use 'big data' from these databases have been published. The national databases have contributed to evidence-based medicine, to the accountability of medical professionals, and to quality assessment and quality improvement of surgery in Japan.
    The Korean journal of thoracic and cardiovascular surgery. 10/2014; 47(5):437-43.
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    ABSTRACT: Antegrade cerebral perfusion and hypothermic circulatory arrest, with or without retrograde cerebral perfusion, are 2 major types of brain protection that are used during aortic arch surgery. We conducted a comparative study of these methods in patients undergoing total arch replacement to evaluate the clinical outcomes in Japan, based on the Japan Adult Cardiovascular Surgery Database. A total of 16,218 patients underwent total arch replacement between 2009 and 2012. Patients with acute aortic dissection or ruptured aneurysm, or who underwent emergency surgery were excluded, leaving 8169 patients for analysis. For the brain protection method, 7038 patients had antegrade cerebral perfusion and 1141 patients had hypothermic circulatory arrest/retrograde cerebral perfusion. A nonmatched comparison was made between the 2 groups, and propensity score analysis was performed among 1141 patients. The matched paired analysis showed that the minimum rectal temperature was lower in the hypothermic circulatory arrest/retrograde cerebral perfusion group (21.2°C ± 3.7°C vs 24.2°C ± 3.2°C) and that the duration of cardiopulmonary bypass and cardiac ischemia was longer in the antegrade cerebral perfusion group. There were no significant differences between the antegrade cerebral perfusion and hypothermic circulatory arrest/retrograde cerebral perfusion groups with regard to 30-day mortality (3.2% vs 4.0%), hospital mortality (6.0% vs 7.1%), incidence of stroke (6.7% vs 8.6%), or transient neurologic disorder (4.1% vs 4.4%). There was no difference in a composite outcome of hospital death, bleeding, prolonged ventilation, need for dialysis, stroke, and infection (antegrade cerebral perfusion 28.4% vs hypothermic circulatory arrest 30.1%). However, hypothermic circulatory arrest/retrograde cerebral perfusion resulted in a significantly higher rate of prolonged stay in the intensive care unit (>8 days: 24.2% vs 15.6%). Hypothermic circulatory arrest/retrograde cerebral perfusion and antegrade cerebral perfusion provide comparable clinical outcomes with regard to mortality and stroke rates, but hypothermic circulatory arrest/retrograde cerebral perfusion resulted in a higher incidence of prolonged intensive care unit stay. Antegrade cerebral perfusion might be preferred as the brain protection method for complicated aortic arch procedures. Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.
    Journal of Thoracic and Cardiovascular Surgery 09/2014; · 3.99 Impact Factor
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    ABSTRACT: Acute diffuse peritonitis (ADP) is an important surgical complication associated with high morbidity and mortality; however, the risk factors associated with a poor outcome have remained controversial. This study aimed in collecting integrated data using a web-based national database system to build a risk model for mortality after surgery for ADP.
    Surgery Today 09/2014; · 1.21 Impact Factor
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    ABSTRACT: The health-care system, homogenous ethnicity, and operative strategy for lower rectal cancer surgery in Japan are to some extent unique compared to those in Western countries. The National Clinical Database is a newly established nationwide, large-scale surgical database in Japan.
    Diseases of the Colon & Rectum 09/2014; 57(9):1075-1081. · 3.20 Impact Factor
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    ABSTRACT: Background:The optimal brain protection strategy for use during acute type A aortic dissection surgery is controversial.Methods and Results:We reviewed the results for 2 different methods: antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP), during ascending aortic repair for acute type A aortic dissection for the period between 2008 and 2012 nationwide. Cases involving root repair, arch vessel reconstruction and/or concomitant procedures were excluded. Using the Japan Adult Cardiovascular Surgery Database, a total of 4,128 patients (ACP, n=2,769; RCP, n=1,359; mean age, 69.1±11.8 years; male 41.9%) were identified. The overall operative mortality was 8.6%. Following propensity score matching, among 1,320 matched pairs, differences in baseline characteristics between the 2 patient groups diminished. Cardiac arrest time (ACP 116±36 vs. RCP102±38 min, P<0.001), perfusion time (192±54 vs. 174±53 min, P<0.001) and operative time (378±117 vs. 340±108 min, P<0.001) were significantly shorter in the RCP group. There were no significant differences between the 2 groups regarding the incidence of operative mortality or neurological complications, including stroke (ACP 11.2% vs. RCP 9.7%). Postoperative ventilation time was significantly longer in the ACP group (ACP 128.9±355.7 vs. RCP 98.5±301.7 h, P=0.018). There were no differences in other early postoperative complications, such as re-exploration, renal failure, and mediastinitis.Conclusions:Among patients undergoing dissection repair without arch vessel reconstruction, RCP had similar mortality and neurological outcome to ACP.
    Circulation Journal 08/2014; · 3.69 Impact Factor
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    ABSTRACT: To construct a risk model for total gastrectomy outcomes using a nationwide Internet-based database.
    Annals of surgery. 07/2014;
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    ABSTRACT: In Japan, the National Clinical Database (NCD) was founded in April 2010 as the parent body of the database system linked to the board certification system. Registration began in 2011, and to date, more than 3,300 facilities have enrolled and more than one million cases are expected to enroll each year. Given the broad impact of this database initiative, considering the social implications of their activities is important. In this study, we identified and addressed issues arising from data collection and analysis, with a primary focus on providing high-quality healthcare to patients and the general public. Improvements resulting from NCD initiatives have been implemented in clinical settings throughout Japan. Clinical research using such database as well as evidence-based policy recommendations can impact businesses, the government and insurance companies. The NCD project is realistic in terms of effort and cost, and its activities are conducted lawfully and ethically with due consideration of its effects on society. Continuous evaluation on the whole system is essential. Such evaluation provides the validity of the framework of healthcare standards as well as ensures the reliability of collected data to guarantee the scientific quality in clinical databases.
    Surgery Today 05/2014; 44(11). · 1.21 Impact Factor
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    ABSTRACT: This study aimed to create a risk model of mortality associated with esophagectomy using a Japanese nationwide database. A total of 5354 patients who underwent esophagectomy in 713 hospitals in 2011 were evaluated. Variables and definitions were virtually identical to those adopted by the American College of Surgeons National Surgical Quality Improvement Program. The mean patient age was 65.9 years, and 84.3% patients were male. The overall morbidity rate was 41.9%. Thirty-day and operative mortality rates after esophagectomy were 1.2% and 3.4%, respectively. Overall morbidity was significantly higher in the minimally invasive esophagectomy group than in the open esophagectomy group (44.3% vs 40.8%, P = 0.016). The odds ratios for 30-day mortality in patients who required preoperative assistance in activities of daily living (ADL), those with a history of smoking within 1 year before surgery, and those with weight loss more than 10% within 6 months before surgery were 4.2, 2.6, and 2.4, respectively. The odds ratios for operative mortality in patients who required preoperative assistance in ADL, those with metastasis/relapse, male patients, and those with chronic obstructive pulmonary disease were 4.7, 4.5, 2.3, and 2.1, respectively. This study was the first, as per our knowledge, to perform risk stratification for esophagectomy using a Japanese nationwide database. The 30-day and operative mortality rates were relatively lower than those in previous reports. The risk models developed in this study may contribute toward improvements in quality control of procedures and creation of a novel scoring system.
    Annals of surgery 04/2014; · 7.19 Impact Factor
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    ABSTRACT: Tricuspid valve insufficiency (TI) following cardiovascular surgery causes right-side heart failure and hepatic failure, which affect patient prognosis. Moreover, the benefits of reoperation for severe tricuspid insufficiency remain unclear. We investigated the surgical outcomes of reoperation in TI. From the Japan Cardiovascular Surgery Database (JACVSD), we extracted cases who underwent surgery for TI following cardiac surgery between January 2006 and December 2011. We analysed the surgical outcomes, specifically comparing tricuspid valve replacement (TVR) and tricuspid valve plasty (TVP). Of the 167 722 surgical JACVSD registered cases, reoperative TI surgery occurred in 1771 cases, with 193 TVR cases and 1578 TVP cases. The age and sex distribution was 684 males and 1087 females, with an average age of 66.5 ± 10.8 years. The overall hospital mortality was 6.8% and was significantly higher in the TVR group than in the TVP group (14.5 vs 5.8%, respectively; P < 0.001). Incidences of dialysis, prolonged ventilation and heart block were also significantly higher in the TVR group than in the TVP group. Logistic regression analysis revealed that the risk factors of hospital mortality were older age, preoperative renal dysfunction, preoperative New York Heart Association Class 4, left ventricular dysfunction and TVR. Surgical outcomes following reoperative tricuspid surgery were unsatisfactory. Although TVR is a last resort for non-repairable tricuspid lesions, it carries a significant risk of surgical mortality. Improving the patient's preoperative status and opting for TVP over TVR is necessary to improve the results of reoperative tricuspid surgery.
    Interactive Cardiovascular and Thoracic Surgery 04/2014; · 1.11 Impact Factor
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    ABSTRACT: The benefits of off-pump coronary artery grafting (OPCAB) have been demonstrated. Especially in patients with a high number of comorbidities, redo coronary artery bypass grafting (CABG) remains a difficult entity of CABG, because patients are likely to have multiple risk factors and often have diseased patent grafts with adhesions. The aim of the present study was to evaluate the effects of the OPCAB technique in redo CABG on mortality and morbidity using data from the Japan Cardiovascular Surgery Database (JCVSD). We analysed 34 980 patients who underwent isolated CABG between 2008 and 2011, as reported in the JCVSD. Of these, 1.8% of patients (n = 617/34980) had undergone redo CABG, including those who underwent OPCAB (n = 364; 69%) and on-pump CABG (n = 253; 41%). We used propensity score (PS) matching with 13 preoperative risk factors to adjust for differences in baseline characteristics between the redo OPCAB and on-pump redo CABG groups. By one-to-one PS matching, we selected 200 pairs from each group. There were no significant differences in patient background between the redo OPCAB and on-pump redo CABG groups after PS matching. There was no significant difference in the mean number of distal anastomoses after matching (2.41 ± 1.00 vs 2.21 ± 1.04, P = 0.074); nevertheless, the mean operation time was significantly shorter in the redo OPCAB than the on-pump redo CABG group (353.7 vs 441.3 min, P < 0.00010). Patients in the redo OPCAB group had a lower 30-day mortality rate (3.5 vs 7.0%, P = 0.18), a significantly lower rate of composite mortality or major morbidities (11.0 vs 21.5%, P = 0.0060), a significantly lower rate of prolonged ventilation (>24 h) (7.0 vs 15.0%, P = 0.016), a significantly shorter duration of intensive care unit (ICU) stay (ICU stay ≥8 days) (7.0 vs 14.5%, P = 0.023) and a significantly decreased need for blood transfusions (71.5 vs 94.0%, P < 0.00010) than patients in the on-pump redo CABG group. The off-pump technique reduced early operative mortality and the incidences of major complications in redo CABG.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 03/2014; · 2.40 Impact Factor
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    ABSTRACT: Since 2008, data concerning pediatric cardiovascular surgeries performed in Japan have been collected in the Japan Congenital Cardiovascular Surgery Database (JCCVSD). We assessed the quality of the JCCVSD data through data verification activities conducted in 2010. During 2008 to 2009, 3345 patients with 4327 procedures at 25 hospitals were registered in the JCCVSD. Among them, six sites were selected for data verification. The completeness of case registration was assessed by comparison with original operational logs. Also, data accuracy of patient demographics, surgical outcomes, and processes were assessed with 10% of the registered cases by comparison with medical records. Verification of case registration completeness involved 968 (28.9%) patients and 1279 (29.1%) procedures. As to completeness, we confirmed 1266 (99.0%) of the 1279 procedures. Data accuracy was verified for 129 (3.9%) patients. Accuracy of status of discharge and 30 and 90 days after surgery were very high (99.2%, 100%, and 100%, respectively). Data items with numeric information exhibited lower exact accuracy due to typing error and inconsistent use of rounding; however, the differences between the submitted and the original data were not statistically significant. High completeness and acceptable range of data accuracy were verified for the data submitted to the JCCVSD in 2008 to 2009. The high accuracy regarding follow-up outcomes was especially noteworthy. The initial success of the JCCVSD should be strengthened through further sophistication of registration protocol, continual training of data managers and auditors, and rigorous expansion of verification activities.
    World journal for pediatric & congenital heart surgery. 01/2014; 5(1):47-53.
  • Mitsukazu Gotoh, Hiroaki Miyata, Hiroyuki Konno
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    ABSTRACT: The National Clinical Database (NCD) was founded in April 2010 as the parent body of a database linked to the surgical board certification system. Registration began in 2011, and to date more than 3,900 facilities have enrolled, with an accumulation of more than 1.02 million cases per year. Related activities will primarily focus on providing high-quality healthcare to patients and the general public, with the clinical setting serving as the driving force behind improvements. Clinical research using the database and evidence-based policy recommendations will impact businesses, the government, and insurers. In the gastroenterological surgery section, 120,000 cases have accumulated with items representing surgical performance in each specialty for eight procedures: esophagectomy; partial and total gastrectomy; right hemicolectomy; low anterior resection; hepatectomy; pancreatoduodenectomy; and surgery for acute diffuse peritonitis. Risk models have been created for the mortality and morbidity of each procedure. These models will be available for participating hospitals and may be useful for decision making by surgeons as well as patient counseling. Studies are in progress using the NCD database to contribute to improving the quality control of surgical procedures.
    Nippon Geka Gakkai zasshi 01/2014; 115(1):8-12.
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    ABSTRACT: To create a mortality risk model after pancreaticoduodenectomy (PD) using a Web-based national database system. PD is a major gastroenterological surgery with relatively high mortality. Many studies have reported factors to analyze short-term outcomes. After initiation of National Clinical Database, approximately 1.2 million surgical cases from more than 3500 Japanese hospitals were collected through a Web-based data entry system. After data cleanup, 8575 PD patients (mean age, 68.2 years) recorded in 2011 from 1167 hospitals were analyzed using variables and definitions almost identical to those of American College of Surgeons-National Surgical Quality Improvement Program. The 30-day postoperative and in-hospital mortality rates were 1.2% and 2.8% (103 and 239 patients), respectively. Thirteen significant risk factors for in-hospital mortality were identified: age, respiratory distress, activities of daily living within 30 days before surgery, angina, weight loss of more than 10%, American Society of Anesthesiologists class of greater than 3, Brinkman index of more than 400, body mass index of more than 25 kg/m, white blood cell count of more than 11,000 cells per microliter, platelet count of less than 120,000 per microliter, prothrombin time/international normalized ratio of more than 1.1, activated partial thromboplastin time of more than 40 seconds, and serum creatinine levels of more than 3.0 mg/dL. Five variables, including male sex, emergency surgery, chronic obstructive pulmonary disease, bleeding disorders, and serum urea nitrogen levels of less than 8.0 mg/dL, were independent variables in the 30-day mortality group. The overall PD complication rate was 40.0%. Grade B and C pancreatic fistulas in the International Study Group on Pancreatic Fistula occurred in 13.2% cases. The 30-day and in-hospital mortality rates for pancreatic cancer were significantly lower than those for nonpancreatic cancer. We conducted the reported risk stratification study for PD using a nationwide surgical database. PD outcomes in the national population were satisfactory, and the risk model could help improve surgical practice quality.
    Annals of surgery 11/2013; · 7.19 Impact Factor
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    ABSTRACT: There has been no report on risk stratification for hepatectomy using a nationwide surgical database in Japan. The objective of this study was to evaluate mortality and variables associated with surgical outcomes of hepatectomy at a national level. We analyzed records of 7,732 patients who underwent hepatectomy for more than 1 segment (MOS) during 2011 in 987 different hospitals, as identified in the National Clinical Database (NCD) of Japan. The NCD captured 30-day morbidity and mortality as well as 90-day in-hospital mortality outcomes, which were submitted through a web-based data entry system. Based on 80% of the population, independent predictors for 30-day mortality and 90-day in-hospital mortality were calculated using a logistic regression model. The risk factors were validated with the remaining 20% of the cohort. The median postoperative length of hospitalization was 16.0 days. The overall patient morbidity rate was 32.1%. Thirty-day mortality and 90-day in-hospital mortality rates were 2.0% and 4.0%, respectively. Totals of 14 and 23 risk factors were respectively identified for 30-day mortality and 90-day in-hospital mortality. Factors associated with risk for 90-day in-hospital mortality were preoperative condition and comorbidity, operative indication (emergency surgery, intrahepatic/perihilar cholangiocarcinoma, or gallbladder cancer), preoperative laboratory data, and extent and location of resected segments (segment 1, 7, or 8). As a performance metric, c-indices of 30-day mortality and 90-day in-hospital mortality were 0.714 and 0.761, respectively. Here we report the first risk stratification analysis of hepatectomy using a Japanese nationwide surgical database. This system would predict surgical outcomes of hepatectomy and be useful to evaluate and benchmark performance.
    Journal of the American College of Surgeons 11/2013; · 4.45 Impact Factor
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    ABSTRACT: The study aim was to collect Japanese data and stratify the operative risk of valve replacement in patients with end-stage renal failure who required dialysis. The Japan Adult Cardiovascular Surgery Database from 167 participating sites was used; a total of 1,616 records obtained between January 2004 and December 2011 was analyzed. Aortic valve replacement was performed in 1,390 of these patients (86%), mitral valve replacement in 372 (23%), and tricuspid valve replacement in eight (0.5%). The operative mortality and morbidity were 13.7% and 32%, respectively. Mechanical valves were frequently used even in patients aged >65 years (49%). Patients with bioprosthetic valves were significantly older and more likely to have comorbidities than those with mechanical valves. The operative mortality (11% versus 17%, p <0.01) and major morbidity (29% versus 37%, p <0.01) were significantly higher in patients with bioprosthetic valves. In multivariate analysis, the type of valve prosthesis was not predictive of death. Significant variables with high odds ratios included chronic lung disease (3.72), peripheral artery disease (2.24), and urgent/emergency status (2.33). The contemporary results of valve replacement for dialysis patients obtained in Japan are acceptable. Mechanical valves are frequently used, regardless of patient age. From the standpoint of an operative risk model, careful preoperative assessment is more important than the choice of valve prosthesis in dialysis patients.
    The Journal of heart valve disease 11/2013; 22(6):850-8. · 0.73 Impact Factor
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    ABSTRACT: Measurement and feedback of clinical performance is one of the important activities in clinical database. In addition, clinical database is used for developing medical guidelines, research for public policy and clinical research, and also various kinds of information can be provided to the public. On the other hand, risk adjustment for data analysis is a key issue in the clinical database. From these viewpoints, this article described the activities for quality improvement, examples of research, and planning of clinical research using the clinical database.
    Kyobu geka. The Japanese journal of thoracic surgery 09/2013; 66(10):919-24.

Publication Stats

389 Citations
225.75 Total Impact Points


  • 2004–2014
    • The University of Tokyo
      • • Faculty & Graduate School of Medicine
      • • School of Medicine
      • • Department of Health Science and Nursing
      Tōkyō, Japan
  • 2011
    • Kyushu University
      • Division of Health Care Administration and Management
      Fukuoka-shi, Fukuoka-ken, Japan
  • 2006
    • Waseda University
      • Department of Health Sciences and Social Welfare
      Tokyo, Tokyo-to, Japan