Thoracic and cardiovascular surgeries in Japan during 2020

All data on cardiovascular, general thoracic, and esophageal surgeries were obtained from the NCD. In 2018, the data collection method for general thoracic and esophageal surgeries had been modi ﬁ ed from self-reports using questionnaire sheets following each institution belonging to the Japanese Association for Thoracic Surgery to an automatic package downloaded from the NCD in Japan. The data collection related to cardiovascular surgery (initially self-reported using questionnaire sheets in each participating institution up to 2014) changed to downloading an automatic package from the Japanese Cardiovascular Surgery Database (JCVSD), which is a cardiovascular subsection of the NCD in 2015.

Since 1986, the Japanese Association for Thoracic Surgery has conducted annual thoracic surgery surveys throughout Japan to determine statistics on the number of procedures performed by surgical categories.Herein, we summarize the results of the association's annual thoracic surgery surveys in 2020.We regret that, for various reasons, this report has been delayed to 2023.
Adhering to the norm thus far, thoracic surgery had been classified into three categories, including cardiovascular, general thoracic, and esophageal surgeries, with patient data for each group being examined and analyzed.We honor and value all members' continued professional support and contributions.
Incidence of hospital mortality was included in the survey to determine nationwide status, which has contributed to Japanese surgeons' understanding of the present status of thoracic surgery in Japan while helping in surgical outcome improvements by enabling comparisons between their work and that of others.This approach has enabled the association to gain a better understanding of present problems and prospects, which is reflected in its activities and member education.
The 30-day mortality (also known as operative mortality) is defined as death within 30 days of surgery, regardless of the patient's geographic location, including post-discharge from the hospital.Hospital mortality is defined as death within any time interval following surgery among patients yet to be discharged from the hospital.
Transfer to a nursing home or a rehabilitation unit is considered hospital discharge unless the patient subsequently dies of complications from surgery, while hospitalto-hospital transfer during esophageal surgery is not considered a form of discharge.In contrast, hospital-to-hospital transfer 30 days following cardiovascular and general thoracic surgeries are considered discharge given that National Clinical Database (NCD)-related data were used in these categories.
Severe Acute Respiratory Syndrpme Coronavirus-2 (SARS-CoV-2), the causative pathogen for the coronavirus disease 2019 (COVID-19), first emerged in Wuhan, China, in December 2019 and by March 2020, it was declared a pandemic [1].The pandemic of SARS-CoV-2 resulted in a global healthcare and financial crisis.There was a significant estimated reduction in national case volume of cardiac surgeries and the cumulative backlog of patients in the United State [2].We have to estimate the nationwide effect of SARS-CoV-2 pandemic on cardiovascular, general thoracic, and esophageal surgeries in Japan, with surgical volume, outcomes and patient data for each group.

Survey abstract
All data on cardiovascular, general thoracic, and esophageal surgeries were obtained from the NCD.In 2018, the data collection method for general thoracic and esophageal surgeries had been modified from self-reports using questionnaire sheets following each institution belonging to the Japanese Association for Thoracic Surgery to an automatic package downloaded from the NCD in Japan.
The data collection related to cardiovascular surgery (initially self-reported using questionnaire sheets in each participating institution up to 2014) changed to downloading an automatic package from the Japanese Cardiovascular Surgery Database (JCVSD), which is a cardiovascular subsection of the NCD in 2015.

Final report: 2020 (A) Cardiovascular surgery
We are extremely pleased with the cooperation of our colleagues (members) in completing the cardiovascular surgery survey, which has undoubtedly improved the quality of this annual report.We are truly grateful for the significant efforts made by all participants within each participating institution in completing the JCVSD/NCD.
Figure 1 illustrates the development of cardiovascular surgery in Japan over the past 34 years.Aneurysm surgery includes only surgeries for thoracic and thoracoabdominal aortic aneurysms.Extra-anatomic bypass surgery for thoracic aneurysm and pacemaker implantation have been excluded from the survey since 2015.Assist device implantations were not included in the total number of surgical procedures but were included in the survey.
A total of 64,075 cardiovascular surgeries, including 54 heart transplants, had been performed in 2020, with a 9.5% decrease compared to that in 2019 (n=70,769).For the first time since the beginning of data collection, except for the year 2015 when there was a decrease due to a change in data collection and aggregation methods, a decline in the number of cases has been observed.Although the impact of the COVID-19 pandemic is suggested, this will be reported separately.
Among the 8595 procedures for congenital heart disease conducted in 2020, 6543 were open-heart surgeries, with an overall hospital mortality rate of 2.0%.The number of surgeries for neonates and infants in 2020 did not significantly differ compared to that in 2010; however, hospital mortality improved from 11.5 to 8.2% for neonates and from 3.0 to 2.1% for infants.In 2020, atrial septal defect was the most common disease (1188 cases) as previously reported, with patients aged ≥18 years accounting for 63% of atrial septal defect surgery.Ventricular septal defect (perimembranous/muscular), which had been the most common disease in 2015 and 2016, was the second most common disease (1043 cases).
Valvular heart disease procedures, excluding transcatheter procedures, were performed less than that in the previous year.Isolated aortic valve replacement/repair with/without coronary artery bypass grafting (CABG) (n=8592) was 16.3%% fewer than that in the previous year (n=10,268) and 0.7% fewer than that 5 years ago (n=8651), as opposed to the rapid increase of transcatheter aortic valve replacement (n= 9774 in 2020).Isolated mitral valve replacement/repairs with/ without CABG (n=4471) was 14.7% fewer than that in the previous year (n=5239) and 1.2% fewer than that 5 years ago (n=4524).Aortic and mitral valve replacement with bioprosthesis were performed in 9278 and 2376 cases, respectively.The rate at which bioprosthesis was used had dramatically increased from 30% in the early 2000s [6,7] to 87.9% and 72.6% in 2020 for aortic and mitral positions, respectively.Additionally, CABG was performed concurrently in 18.6% of all valvular procedures (17.8% in 2010 [4] and 19.8% in 2015 [5]).Valve repair was common in mitral and tricuspid valve positions (5803 and 4033 cases, respectively) but less common in aortic valve positions (173 patients, only 1.6% of all aortic valve procedures).Mitral valve repair accounted for 63.7% of all mitral valve procedures.Hospital mortality rates for single valve replacement for aortic and mitral positions were 3.2% and 7.7%, respectively, but only 1.1% for mitral valve repair.Moreover, hospital mortality rates for redo valve surgery for the aortic and mitral positions were 7.3% and 6.3%, respectively.Finally, overall hospital mortality rates did not significantly improve over the past 10 years (3.4% in 2010 [4], 4.0% in 2015 [5], and 3.6% in 2020).
Isolated CABG had been performed in 10,311 cases, accounting for only 66.4% of the procedures performed 10 years ago (n=15,521) [4].Of the aforementioned cases, 6014 (58.3%) underwent off-pump CABG, with a success rate of 98.0%.The percentage of planned off-pump CABG in 2020 was similar to that in 2019.Hospital mortality associated with primary elective CABG procedures among 8904 cases accounted for 1.7%, which is slightly higher than that in 2010 (1.1%) [4].Hospital mortality for primary emergency CABG among 1307 cases remained high (9.2%).The percentage of conversion from off-pump to onpump CABG or on-pump beating-heart CABG was 2.3% among the primary elective CABG cases, with a hospital mortality rate of 10.7%.Patients with end-stage renal failure

Table 2
Acquired (total, (1)?( 2)?( 4)?( 5)?( 6)?( 7)?isolated operations for arrhythmia in (3); 32,509       on dialysis had higher hospital mortality rates than overall mortality, regardless of surgical procedure (on-pump arrest, on-pump beating, and off-pump).This study excluded concomitant CABGs alongside other major procedures under the ischemic heart disease category but rather under other categories, such as valvular heart disease and thoracic aortic aneurysm.Accordingly, the overall number of CABGs in 2020, including concomitant CABG with other major procedures, was 15,681.Arrhythmia management was primarily performed as concomitant procedures in 6831 cases, with a hospital mortality rate of 3.2%.Pacemaker and implantable cardioverter-defibrillator implantation were not included in this category.
In 2020, 22,540 procedures for thoracic and thoracoabdominal aortae diseases were performed, among which aortic dissection and non-dissection accounted for 10,855 and 11,685, respectively.The number of surgeries for aortic dissection this year was 0.1% higher than that in the preceding year (n=10,847).Hospital mortality rates for the 6200 Stanford type A acute aortic dissections remained high (10.1%).The number of procedures for non-dissected aneurysms decreased by 1.5%, with a hospital mortality rate of 4.9% for all aneurysms and 3.8% and 18.4% for unruptured and ruptured aneurysms, respectively.Thoracic endovascular aortic repair (TEVAR) has been performed for aortic diseases at an increasing rate.Stent graft placement was performed in 4918 patients with aortic dissection, including 2602 TEVARs and 2316 open stent graftings.Moreover, 1568 and 319 cases underwent TEVAR and open stent grafting for type B chronic aortic dissection, accounting for 62.2% and 12.6% of the total number of cases, respectively.Hospital mortality rates associated with simple TEVAR for type B aortic dissection were 7.7% and 0.7% for acute and chronic cases, respectively.Stent graft placement was performed in 5702 patients with non-dissected aortic aneurysms, among which 4090 were TEVARs (an 0.4% increase compared to that in 2019, n=4072) and 1612 were open stent graftings (a 7.5% increase compared to that in 2019, n=1499).Hospital mortality rates were 2.7% and 19.1% for TEVARs and 6.1% and 20.2% for open stenting in unruptured and ruptured aneurysms, respectively.

(B) General thoracic surgery
The 2020 survey of general thoracic surgeries comprised 708 surgical units, with bulk data submitted via a web- based collection system established by the NCD [3].General thoracic surgery departments reported 86,813 procedures in 2020 (Table 7), which is 2.1 times more than that in 2000 and approximately 7038 more procedures than that in 2015 (Fig. 2).However it decreased by 5.3% compared to that of 2019 (91,626), mostly because of COVID-19 pandemic, despite the steadily increase up to 2019.In 2020, 45,436 procedures for primary lung cancer had been performed which decreased by 5.4% compared to that of 2019 (48,052) similarly to the total number of surgeries in general thoracic surgery.The number of procedures in 2020 was 2.4 times higher than that in 2000, with lung cancer procedures accounting for 52% of all general thoracic surgeries.
A total of 2232 procedures for benign pulmonary tumors had been conducted in 2020 (Table 8).Hamartomas were the most frequent benign pulmonary tumors diagnosed, with 2079 patients (93%) undergoing VATS.
Tables 9 and 10 show additional information on primary malignant pulmonary tumors.Accordingly, the most frequently diagnosed lung cancer subtype was adenocarcinoma (70% of all lung cancers), followed by squamous cell carcinoma (18%).Sublobar resection was performed in 14,305 lung cancer cases (31% of all cases) and lobectomy in 30,604 cases (67% of all cases).Sleeve lobectomy was performed in 396 cases (0.9% of all cases), while pneumonectomy was required in 251 cases (0.6% of all cases).VATS lobectomy was performed in 21,179 cases of lung cancer (69% of all lobectomy cases).RATS lobectomy was performed in 2810 cases of lung cancer (9% of all lobectomy cases).Patients aged≥80 years who underwent lung cancer surgery accounted for 6521 (14%).Among those who died within 30 days postoperatively, 122 and 45 died before and after hospital discharge, respectively.Overall, 167 patients died within 30 days postoperatively (30-day mortality rate, 0.4%), while 122 died before discharge (hospital mortality rate, 0.3%).Moreover, 30-day mortality rates according to the procedure were 0.2%, 0.4%, and 2% for segmentectomy, lobectomy, and pneumonectomy, respectively.Interstitial pneumonia had been the leading cause of death after lung cancer surgery, followed by pneumonia, respiratory failure, and cardiovascular events.
The procedures for metastatic pulmonary tumors performed in 2020 increased 3.4% to 9654 cases compared to that in 2019 (9329), which showed contrastive trend to primary lung cancer (Table 11).Among such procedures, the most frequent primary tumor was colorectal cancer (48% of all cases).
A total of 98 procedures for tracheal tumors, including 49, 30, and 19 cases of primary malignant, metastatic, and benign tracheal tumors, respectively, were performed in   12).Overall, 584 pleural tumors had been diagnosed in 2020 (Table 13), with diffuse malignant pleural mesothelioma as the most frequent histologic diagnosis.Total pleurectomy was performed in 105 cases and extrapleural pneumonectomy in 33 cases.The 30-day mortality rate was 2% and 3% after total pleurectomy and extrapleural pneumonectomy, respectively.
A total of 484 patients underwent thymectomy for myasthenia gravis (Table 16), among which 354 procedures were associated with thymoma in 2020.
Overall, 22,043 patients underwent procedures for nonneoplastic disease.Accordingly, 2397 patients underwent lung resection for inflammatory lung diseases (Tables 17,  18), among which 492 and 311 patients were associated with mycobacterial and fungal infections, respectively.Procedures for inflammatory pseudotumor were performed in 1011 cases (42%).
A total of 317 procedures were conducted for bullous diseases (Table 21), while only 14 patients underwent lung volume reduction surgery.
A total of 13,514 procedures were performed for pneumothorax (Table 22).Among the 9592 procedures for spontaneous pneumothorax, 2523 (26%) were bullectomies alone, while 6428 (67%) required additional procedures, such as coverage with artificial material, as well as parietal pleurectomy.A total of 3922 procedures for secondary pneumothorax were performed, with chronic obstructive pulmonary disease (COPD) being the most prevalent associated disease (2775 cases, 71%).The hospital mortality rate for secondary pneumothorax associated with COPD was 3%.
The 2020 survey reported 180 procedures for chest wall deformity (Table 23).However, this may have been underestimated because the Nuss procedure for pectus excavatum was more likely performed in pediatric surgery centers not associated with the Japanese Association for Thoracic Surgery.Surgical treatment for diaphragmatic hernia was performed in 41 patients (Table 24).This may have been underestimated because procedures may have been classified as gastrointestinal surgery.
The survey reported 458 procedures for chest trauma, excluding iatrogenic injuries (Table 25), with a hospital mortality rate of 6.6%.
Table 26 summarizes the procedures for other diseases, including 92 and 99 cases of arteriovenous malformation and pulmonary sequestration, respectively.
A total of 75 lung transplantations were performed in 2020 (Table 27), among which 58 and 17 were from braindead and living-related donors, respectively.
In 2020, the number of VATS procedures decreased by 1.2% from 77,059 to 76,073 compared to that of 2019 with the decrease of all procedures in general thoracic surgery (− 5.3%).However, the population of VATS procedures in all procedures increased to 88% in 2020 compared that in 2019 (84%) (Table 28).
With fistula 346 15 ( Without fistula 303       Tables 30, 31, 32 present the details regarding pediatric surgery and combined resection of neighboring organs.

(C) Esophageal surgery
In 2018, the data collection method for esophageal surgery had been modified from self-reports using questionnaire sheets following each institution belonging to the Japanese Association for Thoracic Surgery to an automatic package downloaded from the NCD in Japan.Consequently, the registry excluded data for non-surgical cases with esophageal diseases.Furthermore, data regarding the histological classification of malignant tumors, multiple primary cancers, and mortality rates for cases with combined resection of other organs could not be registered because they were not included in the NCD.Instead, detailed data regarding postoperative surgical and non-surgical complications were collected from the NCD.Moreover, data regarding surgeries for corrosive esophageal strictures and salvage surgeries for esophageal cancer had been exceptionally registered by participating institutions.
Throughout 2020, 5909 patients underwent surgery for esophageal diseases (860 and 5049 for benign and malignant esophageal diseases, respectively) from institutions across Japan.Compared to 2019, there was a total decrease of 1326 cases (18.3%) observed, with a decrease of 214 cases (19.9%) in benign diseases and a decrease of 1112 cases (18.0%) in malignant diseases.It is considered that this significant decline was largely influenced by the COVID-19 pandemic that began in 2020, with factors such as surgical restrictions, reduced medical visits, and postponed screenings being considered as contributing factors (Fig. 3).
Thoracoscopic and/or laparoscopic esophagectomy was utilized in 1646 (85.4%) and 2468 (79.0%) patients with superficial and advanced cancer, respectively.Incidence of thoracoscopic and/or laparoscopic surgery (minimally invasive esophagectomy: MIE) for superficial or advanced cancer have been increasing, whereas that of open surgery, especially for advanced cancer, has been decreasing annually (Fig. 4).Mediastinoscopic     esophagectomy was slightly increased, and performed for 115 (6.0%) and 127 (4.1%) patients with superficial and advanced esophageal cancer, respectively.Robot-assisted esophagectomy has been remarkably increased since 2018 when the insurance approval was obtained in Japan, and performed for 355 (18.4%) and 479 (15.3%) patients with superficial and advanced esophageal cancer, respectively in 2020.Patients who underwent robot-assisted surgery are increasing for both superficial and advancer esophageal cancers compared to that in 2019 (12.3% and 9.9% in 2019, respectively).Hospital mortality rates within 30 days after thoracoscopic and/or laparoscopic esophagectomy were 0.6% and 0.4% for patients with superficial and advanced cancer, respectively (Table 34).
Detailed data collection regarding postoperative surgical and non-surgical complications was initiated in 2018.Overall, 1087 (21.5%) of 5049 patients developed grade III or higher complications based on the Clavien-Dindo classification in 2020 (Table 34).The incidence of grade III or higher complications was relatively higher in cervical esophageal cancer compared to thoracic or abdominal esophageal cancer.Among surgical complications, anastomotic leakage and recurrent nerve palsy occurred in 14.2% and 13.6% of the patients who underwent right transthoracic esophagectomy, in 11.0% and 14.1% of those who underwent robot-assisted esophagectomy, and in 18.2% and 24.4% of those who underwent mediastinoscopic esophagectomy, respectively.Among non-surgical postoperative complications, pneumonia occurred in 13.8% of the patients, 3.8% of whom underwent unplanned intubation.Postoperative pulmonary embolism occurred in 1.1% of the patients.These complication rates, including the others, were similar to those in 2019.
Salvage surgery following definitive (chemo)radiotherapy was safely performed in 300 patients in 2020, with hospital mortality rates of 0% within 30 days postoperatively.(Table 35).
We aim to continue our efforts in collecting comprehensive survey data through more active collaboration with the Japan Esophageal Society and other related institutions, with caution due to the impact of COVID-19 pandemic.
Open esophagectomy fo superficial and advanced esophageal cancers has begun to be separately counted since 2014.
% mortality CPB cardiopulmonary bypass, PDA patent ductus arteriosus, VSD ventricular septal defect, DORV double outlet right ventricle, AVSD atrioventricular septal defect, TGA transposition of great arteries, SV single ventricle, Interrupt. of Ao. interruption of aorta, PS pulmonary stenosis, PA-IVS pulmonary atresia with intact ventricular septum, TAPVR total anomalous pulmonary venous return, PAPVR partial anomalous pulmonary venous return, ASD atrial septal defect, TOF tetralogy of Fallot, DCRV double-chambered right ventricle, TA tricuspid atresia, HLHS hypoplastic left heart syndrome, RV-PA right ventricle-pulmonary artery % mortality SP systemic-pulmonary, PAB pulmonary artery banding, PA pulmonary artery, RVOT right ventricular outflow tract, CA coronary artery, AV fistula arteriovenous fistula, TCPC total cavopulmonary connection, AV valve atrioventricular valve, VSD ventricular septal defect, AVR aortic valve replacement Valvelar heart disease (total; 18,366) % mortality CABG coronary artery bypass grafting, 1VD one-vessel disease, 2VD two-vessel disease, 3VD three-vessel disease, LMT left main trunk, SVG saphenous vein graft LMT includes LMT alone or LMT with other branch diseases (a-2) On-pump beating CABG (total; 2034) % mortality CABG coronary artery bypass grafting, 1VD one-vessel disease, 2VD two-vessel disease, 3VD three-vessel disease, LMT left main trunk, SVG saphenous vein graft LMT includes LMT alone or LMT with other branch diseasesTable 2 Off-pump CABG (total; 6014) (Including cases of planned off-pump CABG in which, during surgery, the change is made to an on-pump CABG or on-pump beating-heart procedure) % mortality CABG coronary artery bypass grafting, 1VD one-vessel disease, 2VD two-vessel disease, 3VD three-vessel disease, LMT left main trunk, SVG saphenous vein graft LMT includes LMT alone or LMT with other branch diseases (c) Cases of conversion, during surgery, from off-pump CABG to on-pump CABG or on-pump beating-heart CABG (these cases are also included in category (b)) % mortality CABG coronary artery bypass grafting Table2 % mortality MI myocardial infarction; CABG, coronary artery bypass grafting; MVP, mitral valve repair; MVR, mitral valve replacement; VSP, ventricular septal perforation Acute, within 2 weeks from the onset of myocardial infarction (3) Operation for arrhythmia (total; % mortality WPW Wolff-Parkinson-White syndrome, IHD ischemic heart disease Except for 170 isolated cases, all remaining 5164 cases are doubly allocated, one for this subgroup and the other for the subgroup corresponding to the concomitant operations (4) Operation for constrictive pericarditis (total; 210) % mortality AVR aortic valve replacement, MVR mitral valve replacement, CABG coronary artery bypass grafting (6) HOCM and DCM (total; % mortality HOCM hypertrophic obstructive cardiomyopathy, DCM dilated cardiomyopathy, AVR aortic valve replacement, MVR mitral valve replacement, MVP mitral valve repair, CABG coronary artery bypass grafting (7) Other open-heart operation (total; % mortality Ao aorta, AVP aortic valve repair, AVR aortic valve replacement, MVP mitral valve repair, MVR mitral valve replacement, CABG coronary artery bypass grafting, TEVAR thoracic endovascular aortic (aneurysm) repair Acute, within 2 weeks from the onsetTable 3 % mortalityAo aorta, AVP aortic valve repair, AVR aortic valve replacement, MVP mitral valve repair, MVR mitral valve replacement, CABG coronary artery bypass grafting, TEVAR thoracic endovascular aortic (aneurysm) repair

Fig. 2
Fig. 2 Annual trend of general thoracic surgery , 17 patients underwent sleeve resection and reconstruction (Table

Table 9
Primary malignant pulmonary tumor

Table 32
Operation of lung cancer invading the chest wall of the apex

Table 33
Benign esophageal diseases