Hiroyuki Tsukihara

Thoracic and cardiovascular surgery in Japan during 2014

The Japanese Association for Thoracic Surgery has conducted annual surveys of thoracic surgery throughout Japan since 1986 to determine the statistics regarding the number of procedures according to operative category. Here, we have summarized the results from our annual survey of thoracic surgery performed during 2014.

Risk Model of Thoracic Aortic Surgery in 4707 Cases From a Nationwide Single-Race Population Through a Web-Based Data Entry System The First Report of 30-Day and 30-Day Operative Outcome Risk Models for Thoracic Aortic Surgery

Background— The objective of this study was to collect integrated data from nationwide hospitals using a web-based national database system to build up our own risk model for the outcome from thoracic aortic surgery. Methods and Results— The Japan Adult Cardiovascular Surgery Database was used; this involved approximately 180 hospitals throughout Japan through a web-based data entry system. Variables and definitions are almost identical to the STS National Database. After data cleanup, 4707 records were analyzed from 97 hospitals (between January 1, 2000, and December 31, 2005). Mean age was 66.5 years. Preoperatively, the incidence of chronic lung disease was 11%, renal failure was 9%, and rupture or malperfusion was 10%. The incidence of the location along the aorta requiring replacement surgery (including overlapping areas) was: aortic root, 10%; ascending aorta, 47%; aortic arch, 44%; distal arch, 21%; descending aorta, 27%; and thoracoabdominal aorta, 8%. Raw 30-day and 30-day operative mortality rates were 6.7% and 8.6%, respectively. Postoperative incidence of permanent stroke was 6.1%, and renal failure requiring dialysis was 6.7%. OR for 30-day operative mortality was as follows: emergency or salvage, 3.7; creatinine >3.0 mg/dL, 3.0; and unexpected coronary artery bypass graft, 2.6. As a performance metric of the risk model, C-index of 30-day and 30-day operative mortality was 0.79 and 0.78, respectively. Conclusion— This is the first report of risk stratification on thoracic aortic surgery using a nationwide surgical database. Although condition of these patients undergoing thoracic aortic surgery was much more serious than other procedures, the result of this series was excellent.

First Report on 30-day and Operative Mortality in Risk Model of Isolated Coronary Artery Bypass Grafting in Japan

BACKGROUND Risk models of coronary artery bypass grafting (CABG) using a large database are useful for improving surgical quality. To obtain accurate, high-quality assessments of the surgical outcomes, each country should maintain its own database. This study was conducted to collect Japanese data and prepare a risk stratification of isolated CABG procedures using the Japan Adult Cardiovascular Surgery Database (JACVSD). METHODS We analyzed 7133 CABG-only records from 97 participating sites throughout Japan using a data entry form with 255 variables that was sent to the JACVSD office by our Web-based data collection system. The statistical model was constructed by multiple logistic regression. Model discrimination was tested using the area under the receiver operating characteristic curve (C index). Model calibration was tested by the Hosmer-Lemeshow test. RESULTS Of 7133 operations, 47.2% had diabetes mellitus, 14.0% were urgent, and 15.6% involved peripheral vascular disease. The observed 30-day and operative mortality rates were 2.02% and 2.72%, respectively. Significant variables with high odds ratios included emergency or salvage status (3.71), preoperative creatinine value exceeding 3.0 mg/dL (3.59), aortic valve stenosis (3.01), and moderate to severe chronic lung disease (2.86). Hosmer-Lemeshow test and C-index values for 30-day mortality were satisfactory at 0.96 and 0.85, respectively. CONCLUSIONS The results obtained in Japan were at least as good as those reported elsewhere. The performance of our risk model also matched those of the Society of Thoracic Surgeons National Adult Cardiac Database and the European Society Database.

Toward quality improvement of thoracic aortic surgery: estimating volume-outcome effect from nationwide survey.

BACKGROUND Although understanding the association between surgical volume and outcome has been the focus of much research, no study has yet reported the volume-outcome effect for thoracic aortic surgery. METHODS From the clinical database, we identified and analyzed 2875 procedures that took place across 36 centers between 2003 and 2005. The effect of hospital procedural volume was assessed for each outcome measure using a hierarchical mixed-effects logistic regression model. Clinical risk factors, procedural year, clinical processes, range of replacement, hospital volume and surgeon volume were set as fixed effects and sites were used as random intercepts. RESULTS The logistic regression model revealed that hospital thoracic aortic surgery volume was linked to statistically significant decreases in both 30-day mortality (p=0.127: OR 0.988-0.999) and operative mortality (p=0.022: 0.989-0.999). In addition, subgroup analysis showed that increased hospital volume was associated with reduced mortality rates in patients under 65 years of age (p=0.038: 0.982-0.999) and in high-risk surgical candidates (p=0.019: 0.989-0.999). Thoracic aortic surgery volume of surgeons, hospital adult cardiovascular surgery volume and surgeons adult cardiovascular surgery volume did not significantly impact these outcomes. CONCLUSIONS In this study higher annual hospital thoracic aortic surgery volume of hospitals is associated with reduced mortality rates for thoracic aortic surgery. In Japan it is not the hospital general adult cardiovascular surgery volume, but the hospital specific thoracic aortic surgery volume that might be preferable for quality indicator of thoracic aortic surgery.

A novel robust template matching method to track and follow body targets for NIUTS

The authors have developed a bed-type non-invasive ultrasound theragnostic system (NIUTS) that compensates for movement by tracking and following the area to be treated by stereo ultrasound imaging while irradiating high-intensity focused ultrasound (HIFU) onto the affected area. In this paper, we propose a novel robust template matching method to track and follow body targets, which include tumors and stones for the NIUTS. The proposed novel robust template matching method could be applied to a motion tracking of the real human kidney based on the ultrasound images, which is the first successful report as far as I know. This robust visual servoing method could be a great tool to treat the tumors and stones precisely and safely.

A novel redundant motion control mechanism in accordance with medical diagnostic and therapeutic task functions for a NIUTS

The authors have developed a non-invasive ultrasound theragnostic system (NIUTS) with a focal lesion servo (FLS) function based on stereo ultrasound imaging in order to compensate for movement while irradiating high-intensity focused ultrasound (HIFU) onto a focal lesion. In the present paper, we propose a redundant motion control mechanism of the HIFU focus, for therapeutics, that is independent of the ultrasound probes for diagnostics. Using the proposed redundant motion control mechanism, an arbitrary designated position in the focal lesion can be treated without altering the viewpoint of the ultrasound probes. The proposed mechanism enables (i) noise factors, which deteriorate the image quality (IQ) for FLS, to be reduced, thereby enhancing the FLS performance, and (ii) enables the destruction of a focal lesion (kidney stone) with a preoperatively designated locus that is moving due to respiration/heartbeat.

Construction of kidney phantom model with acoustic shadow by rib bones and respiratory organ motion

We have been studying the Non-Invasive Ultrasound Theragnostic System (NIUTS), which tracks and follows the affected area while irradiating High Intensity Focused Ultrasound (HIFU). In this report, we propose a phantom model that includes rib bones and respiratory motion.

Simultaneous evaluation of wall motion and blood perfusion of a beating heart using stereoscopic fluorescence camera system.

In this study, we aimed to develop a stereoscopic fluorescence camera system for simultaneous evaluation of wall motion and tissue perfusion using indocyanine green (ICG) fluorescence imaging. The system consists of two high-speed stereo cameras, an excitation lamp, and a computer for image processing. Evaluation experiments demonstrated that the stereoscopic fluorescence camera system successfully performed the simultaneous measurement of wall motion and tissue perfusion based on ICG fluorescence imaging. Our system can be applied to intraoperative evaluation of cardiac status, leading to an improvement in surgical outcomes.

Endoscope system with plasma flushing and coaxial round jet nozzle for off-pump cardiac surgery

BackgroundTo develop a new endoscope for performing simple surgical tasks inside the blood-filled cardiac atrium/chamber, that is, “off-pump” cardiac surgeries.MethodsWe developed the endoscope system with plasma flushing and coaxial round jet nozzle. The “plasma flushing” system was invented to observe the interior of the blood-filled heart by displacing blood cells in front of the endoscope tip. However, some areas could not be observed with simple flushing of the liquid because the flushed liquid mixed with blood. Further, a large amount of liquid had to be flushed, which posed a risk of cardiac damage caused by excess volume. Therefore, to safely capture high-resolution images of the interior of the heart, an endoscope with a coaxial round jet nozzle through which plasma is flushed has been developed. And to reduce the volume of flushed liquid, the synchronization system of heartbeat and the endoscope system with plasma flushing has been developed.ResultsWe conducted an in vivo experiment to determine whether we could observe intracardiac tissues in swine without the use of a heart–lung machine. As a result, we successfully observed intracardiac tissues without using a heart–lung machine. By using a coaxial nozzle, we could even observe the tricuspid valve. Moreover, we were able to save up to 30% of the flushed liquid by replacing the original system with a synchronization system. And we evaluated the performance of the endoscope with the coaxial round jet nozzle by conducting fluid analysis and an in vitro experiment.ConclusionWe successfully observed intracardiac tissues without using a heart–lung machine. By using a coaxial nozzle, we could even observe the tricuspid valve. And by replacing an original system to a synchronization system, we were able to save up to 30% of the flushed liquid. As a follow-up study, we plan to create a surgical flexible device for valve disease that can grasp, staple, and repair cardiac valves by endoscopic visualization

Current status of cardiovascular surgery in Japan, 2013 and 2014: A report based on the Japan Cardiovascular Surgery Database (JCVSD). 1: Mission and history of JCVSD

The Japan Cardiovascular Surgery Database (JCVSD) was created in 2000 with the support of the Society of Thoracic Surgeons (STS). The STS database content was translated to Japanese using the same disease criteria and in 2001, data entry for adult cardiac surgeries was initiated online using the University Hospital Medical Information Network (UMIN). In 2008, data entry for congenital heart surgeries was initiated in the congenital section of JCVSD and preoperative expected mortality (JapanSCORE) in adult cardiovascular surgeries was first calculated using the risk model of JCVSD. The Japan Surgical Board system merged with JCVSD in 2011, and all cardiovascular surgical data were registered in the JCVSD from 2012 onward. The reports resulting from the data analyses of the JCVSD will encourage further improvements in the quality of cardiovascular surgeries, patient safety, and medical care in Japan.