Thoracic and cardiovascular surgery in Japan during 2013

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 2013. 
 
The incidence of hospital mortality was added to the survey to determine the nationwide status, which has contributed to the Japanese surgeons to understand the present status of thoracic surgery in Japan and to make progress to improve operative results by comparing their work with those of others. The Association was able to gain a better understanding of present problems as well as future prospects, which has been reflected to its activity including education of its members. Thirty-day mortality (so called “operative mortality”) is defined as death within 30 days of operation regardless of the patient’s geographic location and even though the patient had been discharged from the hospital. 
 
Hospital mortality is defined as death within any time interval after an operation if the patient had not been discharged from the hospital. Hospital-to-hospital transfer is not considered discharge: transfer to a nursing home or a rehabilitation unit is considered hospital discharge unless the patient subsequently dies of complications of the operation. (The definitions of the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity of the Society of Thoracic Surgeons and the American Association for Thoracic Surgery (Edmunds et al. Ann Thorac Surg 1996;62:932–5; J Thorac Cardiovasc Surg 1996;112:708–11). 
 
Thoracic surgery was classified into three categories—cardiovascular, general thoracic, and esophageal surgery—and the patient data were examined and analyzed for each group. Access to the computerized data is offered to all members of this Association. We honor and value all member’s continued kind support and contributions (Tables 1, ​,22). 
 
 
 
Table 1 Questionnaires sent out and received back by the end of December 2014 
 
 
 
 
 
Table 2 Categories subclassified according to the number of operations performed

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 2013.
The incidence of hospital mortality was added to the survey to determine the nationwide status, which has contributed to the Japanese surgeons to understand the present status of thoracic surgery in Japan and to make progress to improve operative results by comparing their work with those of others. The Association was able to gain a better understanding of present problems as well as future prospects, which has been reflected to its activity including education of its members. Thirty-day mortality (so called ''operative mortality'') is defined as death within 30 days of operation regardless of the patient's geographic location and even though the patient had been discharged from the hospital.
Hospital mortality is defined as death within any time interval after an operation if the patient had not been discharged from the hospital. Hospital-to-hospital transfer is not considered discharge: transfer to a nursing home or a rehabilitation unit is considered hospital discharge unless the patient subsequently dies of complications of the operation. (The definitions of the Ad Hoc Liaison Committee for Standardizing Definitions of Prosthetic Heart Valve Morbidity of the Society of Thoracic Surgeons and the American Association for Thoracic Surgery (Edmunds et al. Ann Thorac Surg 1996;62:932-5;J Thorac Cardiovasc Surg 1996;112:708-11).
Thoracic surgery was classified into three categoriescardiovascular, general thoracic, and esophageal surgeryand the patient data were examined and analyzed for each group. Access to the computerized data is offered to all members of this Association. We honor and value all member's continued kind support and contributions (Tables 1, 2).

Abstract of the survey
We sent out survey questionnaire forms to the departments of each category in all 1535 institutions (602 cardiovascular, 793 general thoracic and 577 esophageal) nationwide in early April 2014. The response rates in each category by the end of December 2014 were 97.8, 96.0, and 96.9 %, respectively. This high response rate has been keep throughout recent survey, and more than 96 % response rate in all fields in 2013 survey has to be congratulated.

Final report (A) Cardiovascular surgery
First, we are very pleased with the high response rate to our survey of cardiovascular surgery (97.8 %), which definitely enhances the quality of this annual report. We very much appreciate the enormous effort put into completing the survey at each participating institution. Figure 1 shows the development of cardiovascular surgery in Japan over the last 27 years. Aneurysm surgery includes only operations for thoracic and thoracoabdominal aortic aneurysm. Pacemaker implantation includes only trans-thoracic implantation and trans-venous implantation is excluded. The number of pacemaker and assist device implantation operations is not included in the total number of surgical operations. A total of 67,325 cardiovascular operations were performed at 589 institutions during 2013 alone and included 36 heart transplantations, which were re-started in 1999, and 1 heart and lung transplantation.
The number of operations for congenital heart disease (9366 cases) decreased slightly (2.0 %) compared with that of 2012 (9558 cases), while there was 2.1 % increase when compared with the data of 10 years ago (9168 cases in 2003). The number of operations for adult cardiac disease (21,758 cases in valvular heart disease, 15,757 cases in thoracic aortic aneurysm and 1871 cases for other procedures) increased compared with those of 2012 (4.0, 4.6 and 14.6 %, respectively) except for ischemic heart disease (16,752 cases,) which decreased 1.9 % of that in 2012. During the last 10 years, the numbers of operations for adult heart disease increased constantly except for that for ischemic heart disease (83.4 % increase in valvular heart disease, 25.4 % decrease in ischemic heart disease, 120.9 % increase in thoracic aortic aneurysm, and 45.7 % increase in other procedures compared those of 2003). The concomitant coronary artery bypass grafting procedure (CABG) is not included in ischemic heart disease but included in other categories such as valvular heart disease and thoracic aneurysm in our study; then, the number of CABG still remained over 20,000 cases per year (21,242 cases) in 2013, which is 87.8 % of that in 2003 (24,204 cases). Data for individual categories are summarized in tables through 3 to 9.
In 2013, 7150 open-heart operations for congenital heart disease were performed with overall hospital mortality of 2.2 % ( Table 3). The number of operations for congenital heart disease was quite steady throughout these 10 years (maximum 7386 cases in 2006), while overall hospital mortality decreased gradually from that of 3.7 % in 2003. In detail, the most common disease was atrial septal defect (1321 cases); however, its number deceased to 71.7 % of that in 2003, which might be due to the recent development of catheter closure of atrial septal defect in Japan. Hospital mortality for complex congenital heart disease improved dramatically in the last 10 years such as interrupted aortic arch with ventricular septal defect (6.7 % in 2003 to 4.9 % in 2013), complete atrioseptal defect (5.7-0.6 %), tetralogy of Fallot (2.6-1.4 %), transposition of the great arteries with and without ventricular septal defect (10.5-5.2 % and 7.5-3.6 %, respectively), single ventricle (7.1-5.7 %), and hypoplastic left heart syndrome (27.2-9.1 %). Right heart bypass surgery is now commonly performed (356 bidirectional Glenn procedures excluding 77 Damus-Kaye-Stansel procedures and 450 Fontan type procedures including total cavo-pulmonary connection) with acceptable hospital mortality (2.0 and 1.6 %). Norwood type I procedure was performed in 108 cases with relatively low hospital mortality rate of 18.5 %.
As previously mentioned, the number of operations for valvular heart disease increased by 83.4 % in the last 10 years, and the hospital mortality associated with primary single valve placement was 2.2 and 3.7 % for the aortic and the mitral position, while that for primary mitral valve repair was 0.8 % (Table 4 (1)). However, hospital mortality rate for redo valve surgery were still high, and was 9.1 and 5.6 % for aortic and mitral procedure, respectively. Finally, overall hospital mortality did not show significant improvement during the last 10 years (3.7 % in 2003 and 3.1 % in 2013), which might be partially due to the recent progression of age of the patients. Repair of the valve became popular procedure (436 cases in the aortic, 6231 cases in the mitral, and 4910 cases in the tricuspid), and mitral valve repair constituted 28.6 % of all valvular heart disease operation and 55.5 % of all mitral valve procedure (10,577 procedures), which are similar to those of the last 5 years and increased compared with those of 2003 (21.3 and 38.7 %, respectively). Aortic and mitral valve replacement with bioprosthesis were performed in 10,000 cases and 2580 cases, respectively, with the number consistently increasing in the aortic position. The ratio of prostheses changed dramatically during the last 10 years and the usage of bioprosthesis is 78.1 % at the aortic position (38.2 % in 2003) and 41.9 % at the mitral position (23.4 % in 2003). CABG as a concomitant procedure performed in 17.8 % of operations for all valvular heart disease (12.7 % in 2003).
Isolated CABG was performed in 15,333 cases which were only 72.9 % of that of 10 years ago (2003) ( The operative and hospital mortality rates associated with primary elective CABG procedures in 13,024 cases were 1.0 and 1.7 %, respectively. Similar data analysis of CABG including primary/redo and elective/emergency data was begun in 2003, and the operative and hospital mortality rates associated with primary elective CABG procedures in 2003 were 1.0 and 1.5 %, respectively; so operative results of primary CABG has been stable. However, hospital mortality of primary emergency CABG in 2121 cases was 5.5 %, which has been improved compared with 9.7 % of hospital mortality rate in 2003. In comparison with data in 2003, the results of conversion improved both conversion rate (3.1-1.7 %) and hospital mortality (8.5-6.4 %).
A total of 1226 patients underwent surgery for complications of myocardial infarction, including 414 operations for a left ventricular aneurysm or ventricular septal perforation or cardiac rupture and 298 operations for ischemic mitral regurgitation.
Operations for arrhythmia were performed mainly as a concomitant procedure in 4000 cases with satisfactory mortality (1.6 % hospital mortality) including 3763 MAZE procedures. MAZE procedure has become quite popular procedure when compared with that in 2003 (1472 cases).
Operations for thoracic aortic dissection were performed in 6787 cases (Table 5). For 4444 Stanford type A acute aortic dissections, hospital mortality was 9.1 %, which was slightly improved compared to that in 2012 (10.6 %) and better than that in 2003 (14.5 %). Operations for a nondissected thoracic aneurysm were carried out in 8171 cases, with overall hospital mortality of 4.5 %, which was better than that in 2012 (5.4 %). The hospital mortality associated with un-ruptured aneurysm was 2.2 %, and that of ruptured aneurysm was 22.2 %, which remains markedly high.   1987  1988  1989  1990  1991  1992  1993  1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009           Values in parenthesis represent mortality % CPB cardiopulmonary bypass, PDA patient ductus arteriosus, VSD                    Values in parenthesis represent mortality %

(B) General thoracic surgery
The total number of operations reported in 2013 in general thoracic surgery has reached 75,306, which means increase of 2559 cases compared with the number of operations in 2012 ( Fig. 2 Table 10). Figure 2 shows the development of thoracic surgery in Japan over 27 years. Data for individual categories are summarized in table through 10 to 34. The number of operations for primary lung cancer in 2013 was 37,008, showing the steady increase (31,301, 2009; 32,801, 2010; 33,878, 2011; 35,667, 2012). Surgery for lung cancer consists of 49.1 % of all the general thoracic surgery. Among lung cancer subtypes, adenocarcinoma comprises an overwhelming percentage of 69.1 % of the total lung cancer surgery, followed by squamous cell carcinoma of 19.9 %. Limited resection by wedge resection or segmentectomy was performed in 8771 lung cancer patients, which is 23.7 % of the entire cases. Lobectomy was performed in 27,469 patients, which is 74.2 % of the entire cases. Sleeve lobectomy was done in 449 patients. Pneumonectomy was done in 559 patients which is only 1.5 % of the entire cases. VATS (video assisted thoracic surgery) procedure is performed in 70.8 % among the total lung cancer surgeries. VATS procedure was adopted in 4270 patients (86.2 %) in wedge resection, 2800 patients (73.4 %) in segmentectomy, 18,925 patients (68.9 %) in lobectomy, and 82 patients (14.7 %) in pneumonectomy. There were 123 patients who died within 30 days after lung cancer surgery (30-day mortality rate; 0.33 %), and 224 patients died without discharge (hospital mortality rate; 0.60 %). 30-day mortality rate in regard to procedures is 0.21 % in segmentectomy, 0.34 % in lobectomy, and 1.97 % in pneumonectomy (Table 12).
Interstitial pneumonia was the leading cause of death after lung cancer surgery, followed by pneumonia, respiratory failure, cardiovascular event, and bronchopleural fistula (Table 13). 7829 patients with metastatic pulmonary tumor were operated in 2013 with steady increase similarly to lung cancer surgery (6248, 2009; 6748, 2010; 7210, 2011; 7403, 2012). VATS was adopted in 6323 cases, which comprises 80.8 % of the entire cases. Colo-rectal cancer was by far the leading primary malignancy indicated for resection of metastatic tumors, which comprises 49.8 % of the entire cases (Table 14).
85 tracheal tumors were operated in 2013. Adenoid cystic carcinoma and squamous cell carcinoma were frequent primary tracheal tumors (Table 15). 439 tumors of pleural origin were operated in 2013. Diffuse malignant pleural mesothelioma was the most frequent histology. Extrapleural pneumonectomy was the most frequently chosen operative method (119 cases) with a hospital death of 8.4 % (Table 16).
Thymectomy for myasthenia gravis was done in 524 patients, and 271 patients were associated with thymoma, 253 patients were not associated with thymoma. VATS was adopted in 176 cases, which comprises 33.6 % of the entire cases (Table 19).
Lung resection for inflammatory lung diseases were done in 3, 445 patients in 2013. Inflammatory pseudotumor comprised 38.8 % of the entire cases, followed by atypical mycobacterium infection (16.7 %) and fungal infections (13.0 %) (Table 20)     Values in parenthesis represent mortality %                           empyema. It should be noted that hospital mortality was as high as 10.9 % in patients of acute empyema with fistura (Table 21). 14,612 operations for pneumothorax were reported in 2013. 13,961 operations (95.5 %) were performed by VATS (Table 24). 61 lung transplantations were reported in 2013. Braindead donor lung transplantation and living-related donor lung transplantation were done in 41 recipients and 20 recipients, respectively. The number of lung transplantation is still small compared to those in North America and European countries because of shortage of donors (Table 29).

(C) Esophageal surgery
During 2013 alone, a total of 17,656 patients with esophageal diseases were registered from 559 institutions (response rate 96.9 %) which affiliated to the Japanese Association for Thoracic Surgery and/or to the Japan Esophageal Society (Table 1). Among these institutions, those where 20 or more patients underwent esophageal surgeries within the year of 2013 were 186 institutions (33.3 %), which shows no definite shift of esophageal operations to high volume institutions when compared to the data of 2012 (33.2 %) (Table 35). Of 7562 patients with a benign esophageal disease, 1300 (17.2 %) patients underwent surgery, and 761 (10.1 %) patients underwent endoscopic resection, while 5501 (72.7 %) patients did not undergo any surgical treatment (Table 36). Of 10,094 patients with a malignant esophageal tumor, 7677 (76.1 %) patients underwent resection, esophagectomy for 5824 (57.7 %) and endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) for 1853 (18.4 %), while 2417 (23.9 %) patients did not undergo any resection (Tables 37, 38). The increase of registered patients with endoscopic resection and nonsurgically treated benign esophageal diseases is obvious during 2012 and 2013. The patients registered, particularly those undergoing ESD or EMR and nonsurgical therapy for a malignant esophageal disease, have been increasing since 1990 (Fig. 3).
Among benign esophageal diseases (Table 36), hiatal hernia, esophageal varices, esophagitis (including reflux esophagitis) and achalasia were the most common conditions in Japan. On the other hand, spontaneous rupture of the esophagus, benign esophageal tumors and congenital esophageal atresia were common diseases which were surgically treated as well as the above-mentioned diseases. The thoracoscopic and/or laparoscopic procedures have been widely adopted for benign esophageal diseases, in particular achalasia, hiatal hernia and benign tumors. Open surgery was performed in 989 patients with a benign esophageal disease, with 30-day mortality in 10 (1.0 %), while thoracoscopic and/or laparoscopic surgery was performed for 311 patients, with 2 (0.6 %) of the 30-day mortality The difference in these death rates between open and scopic surgery seem to be related the conditions requiring open surgery.
The majority of malignant diseases were carcinomas (Table 37). Among esophageal carcinomas, the incidence of squamous cell carcinoma was 91.1 %, while that of adenocarcinomas including Barrett cancer was 6.4 %. The resection rate for patients with a squamous cell carcinoma was 75.0 %, while that for patients with an adenocarcinoma was 91.0 %.
According to location, cancer in the thoracic esophagus was the most common (Table 38). Of the 3748 patients (37.1 % of total esophageal malignancies) having superficial esophageal cancers within mucosal and submucosal layers, 1799 (48.0 %) patients underwent esophagectomy, while 1757 (46.9 %) patients underwent EMR or ESD. The 30-day mortality rate and hospital mortality rate after esophagectomy for patients with a superficial cancer were 0.2 and 0.5 % respectively. Advanced esophageal cancer invading deeper than the submucosal layer was observed in 6224 (61.7 %) patients. Of the 6224 patients with advanced esophageal cancer, 4025 (64.7 %) underwent esophagectomy, with 0.8 % of the 30-day mortality rate, and with 2.3 % of the hospital mortality rate.
Multiple primary cancers were observed in 1662 (16.5 %) of all the 10,094 patients with esophageal cancer. Synchronous cancer was found in 873 (52.5 %) patients, while metachronous cancer (found before esophageal cancer) was observed in 786 (47.3 %) patients. The stomach is the commonest site for both synchronous and metachronous malignancy followed by head and neck cancer (Table 38).
Among esophagectomy procedures, transthoracic esophagectomy through right thoracotomy was the most commonly adopted for patients with a superficial cancer as well as for those with an advanced cancer (Table 39). Transhiatal esophagectomy commonly performed in Western countries was adopted in only 4.6 % of patients having a superficial cancer who underwent esophagectomy and in 1.5 % of those having an advanced cancer in Japan. The thoracoscopic and/or laparoscopic esophagectomy were adopted for 1049 patients (58.3 %) with a superficial cancer, and for 1326 patients (32.9 %) with an advanced cancer. The number of cases of thoracoscopic and/or laparoscopic surgery for superficial or advanced cancer has been increasing for these several years (Fig. 4).
Combined resection of the neighboring organs during resection of an esophageal cancer was performed in 281 patients (Tables 39,40). Resection of the aorta together with the esophagectomy was performed in 2 cases. Tracheal and/or bronchial resection combined with esophagectomy was performed in 44 patients, with the 30-day mortality rate at 0 % and the hospital mortality rate at 2.3 %. Lung resection combined with esophagectomy was performed in 77 patients, with the 30-day mortality rate at 1.3 % and the hospital mortality rate at 5.2 %.
Salvage surgery after definitive (chemo-) radiotherapy was performed in 234 patients, with the 30-day mortality rate at 0.9 % and with the hospital mortality rate at 6.0 % (Table 39).    (2    Values in parenthesis represent mortality % Lastly, in spite of the efforts of the Committee to cover wider patient populations to this annual survey, the majority of the institutions which responded to the questionnaire were the departments of thoracic or esophageal surgery. It should be noted that larger number of patients with esophageal diseases should have been treated medically and endoscopically. We should continue our effort for complete survey through more active collaboration with the Japan Esophageal Society and other related societies.