Prognostic factors after open and endovascular repair for infected native aneurysms of the abdominal aorta and common iliac artery.

OBJECTIVE: Infected native aneurysms (INAs) of the abdominal aorta and iliac arteries are uncommon, but potentially fatal. Endovascular aneurysm repair (EVAR) has recently been introduced as a durable treatment option, with outcomes comparable to those yielded by conventional open repair. However, owing to the rarity of the disease, the strengths and limitations of each treatment remain uncertain. The present study aimed to separately assess post-open repair and post-EVAR outcomes and to clarify factors affecting the short-term and late prognosis after each treatment. METHODS: Using a nationwide clinical registry, we investigated 600 patients treated with open repair and 226 patients treated with EVAR for INAs of the abdominal aorta and/or common iliac artery. The relationships between preoperative or operative factors and postoperative outcomes, including 90-day and 3-year mortality and persistent or recurrent aneurysm-related infection, were examined. RESULTS: Prosthetic grafts were used in >90% of patients treated with open repair, and in situ and extra-anatomic arterial reconstruction was performed in 539 and 57 patients, respectively. Preoperative anemia and imaging findings suggestive of aneurysm-enteric fistula were independently associated with poor outcomes in terms of both 3-year mortality (hazard ratio [HR], 1.62; 95% confidence interval [CI], 1.01-2.62; P = .046, and HR, 2.24; 95% CI, 1.12-4.46; P = .022, respectively) and persistent or recurrent infection (odds ratio [OR], 2.16; 95% CI, 1.04-4.49; P = .039, and OR, 4.96; 95% CI, 1.81-13.55; P = .002, respectively) after open repair, whereas omental wrapping or packing and antibiotic impregnation of the prosthetic graft for in situ reconstruction contributed to improved 3-year survival (HR, 0.60; 95% CI, 0.39-0.92; P = .019, and HR, 0.53; 95% CI, 0.32-0.88; P = .014, respectively). Among patients treated with EVAR, abscess formation adjacent to the aneurysm was significantly associated with the occurrence of persistent or recurrent infection (OR, 2.24; 95% CI, 1.06-4.72; P = .034), whereas an elevated preoperative white blood cell count was predictive of 3-year mortality (HR, 1.77; 95% CI, 1.00-3.13; P = .048). CONCLUSIONS: Profiles of prognostic factors differed between open repair and EVAR in the treatment of INAs of the abdominal aorta and common iliac artery. Open repair may be more suitable than EVAR for patients with concurrent abscess formation.

Surgical Treatment for Popliteal Artery Entrapment Syndrome in Japan: a Retrospective, Multicentre Study Using a National Clinical Registry.

OBJECTIVE: Surgical treatment is an established method for popliteal artery entrapment syndrome (PAES), which, however, mainly derives from single centre experiences where PAES cases are centralised and treated periodically. This study evaluated clinical outcomes of surgical treatment for PAES in a clinical setting where PAES cases were not centralised. METHODS: Multicentre, retrospective cohort study using a national clinical registry. From a Japanese nationwide clinical registry, data for patients who underwent surgical treatment for PAES between 2013 and 2018, including 58 limbs from 41 institutes, were retrieved and evaluated. Patency was analysed using Kaplan-Meier curves. RESULTS: The mean patient age was 36 ± 19 years, 78% were male, and the incidence of PAES was 0.24 limbs/centre/year, reflecting a clinical setting where PAES cases are not centralised. The most frequent arterial symptom was intermittent claudication (90%). Computed tomography was performed in 57 limbs (98%) for the diagnosis, however active manoeuvres such as dorsiflexion and plantarflexion during the examination was performed in only 13 limbs (22%), and occlusion of the popliteal artery was present in 38 limbs (66%) at diagnosis. Regarding surgical treatment, myotomy alone was performed in only seven limbs (12%), and other limbs were revascularised. Mean follow up was 26 ± 20 months, and surgical treatment was effective as it relieved symptoms in > 96% of limbs, with five year primary and secondary patency of the surgical treatment for PAES of 72% and 93%, respectively. CONCLUSION: Results of surgical treatment were acceptable even in a clinical setting where PAES cases were not centralised. However, a low incidence of active manoeuvres performed during the examination and a high incidence of occlusion at diagnosis suggests there may be delayed or underdiagnosis of PAES in Japan, and increased awareness for PAES is warranted.

Report of the 23rd nationwide follow-up survey of primary liver cancer in Japan (2014-2015).

For the 23rd Nationwide Follow-up Survey of Primary Liver Cancer in Japan, data from 20 889 newly registered patients and 42 274 previously registered follow-up patients were compiled from 516 institutions over a 2-year period from January 1, 2014 to December 31, 2015. Basic statistics compiled for patients newly registered in the 23rd survey were cause of death, past medical history, clinical diagnosis, imaging diagnosis, treatment-related factors, pathological diagnosis, recurrence status, and autopsy findings. Compared with the previous 22nd survey, the population of patients with hepatocellular carcinoma (HCC) was older at the time of clinical diagnosis, had more female patients, had more patients with non-B non-C HCC, had smaller tumor diameter, and was more frequently treated with hepatectomy. Cumulative survival rates were calculated for HCC, intrahepatic cholangiocarcinoma, and combined hepatocellular cholangiocarcinoma (combined HCC and intrahepatic cholangiocarcinoma) by treatment type and background characteristics for patients newly registered between 2004 and 2015 whose final outcome was survival or death. The median overall survival and cumulative survival rates for HCC were calculated by dividing patients by combinations of background factors (number of tumors, tumor diameter, Child-Pugh grade, or albumin-bilirubin grade) and by treatment type (hepatectomy, radiofrequency ablation therapy, transcatheter arterial chemoembolization, hepatic arterial infusion chemotherapy, and systemic therapy). The same values were also calculated according to registration date by dividing patients newly registered between 1978 and 2015 into five time period groups. The data obtained from this nationwide follow-up survey are expected to contribute to advancing clinical research and treatment of primary liver cancer in the world.

Impact of the hospital volume and setting on postoperative complications of surgery for gastroenterological cancers in a regional area of Western Japan.

PURPOSE: A research subgroup was established by the Japanese Society of Gastroenterological Surgery to improve the health care quality in the Chushikoku area of Western Japan. METHODS: The records of four surgical procedures were extracted from the Japanese National Clinical Database and analyzed retrospectively to establish the association between hospital characteristics, defined using a combination of hospital case-volume and patients' hospital travel distance, and the incidences of perioperative complications of ≥ Grade 3 of the Clavien-Dindo classification after gastroenterological surgery. RESULTS: This study analyzed 11,515 cases of distal gastrectomy for gastric cancer, 4,705 cases of total gastrectomy for gastric cancer, 4,996 cases of right hemicolectomy for colon cancer, and 5,243 cases of lower anterior resection for rectal cancer, with composite outcome incidences of 5.6%, 10.2%, 5.5%, and 10.7%, respectively. After adjusting for patient characteristics and surgical procedures, no association was identified between the hospital category and surgical outcomes. CONCLUSION: The findings of our study of the Chushikoku region did not provide positive support for the consolidation and centralization of hospitals, based solely on hospital case volume. Our grouping was unique in that we included patient travel distance in the analysis, but further investigations from other perspectives are needed.

Comprehensive registry of esophageal cancer in Japan, 2015.

BACKGROUND: The registration committee for esophageal cancer in the Japan Esophageal Society (JES) has collected the patients' characteristics, treatment, and outcomes of patients who underwent any treatment during 2015 in Japan. METHODS: We analyzed patients' data who had visited the participating hospitals in 2015. We collected the data using the National Clinical Database with a web-based data collection system. We used the Japanese Classification of Esophageal Cancer 10th edition by JES and the TNM classification by the Union of International Cancer Control (UICC) for cancer staging. RESULTS: A total of 9368 cases were registered from 355 institutions in Japan. Squamous cell carcinoma and adenocarcinoma accounted for 86.7% and 7.4%, respectively. The 5-year survival rates of patients treated by endoscopic resection, concurrent chemoradiotherapy, radiotherapy alone, and esophagectomy were 87.2%, 33.5%, 24.2%, and 59.9%, respectively. Esophagectomy was performed in 5172 cases. Minimally invasive approaches were selected for 60.6%, and 54.4% underwent thoracoscopic esophagectomy. The operative mortality (within 30 days after surgery) was 0.79% and the hospital mortality was 2.3%. The survival curves showed an excellent discriminatory ability both in the clinical and pathologic stages by the JES system. The survival of pStage IV was better than IIIC in the UICC system because pStage IV included the patients with supraclavicular lymph node metastasis (M1 LYM). CONCLUSION: We hope this report improves all aspects of diagnosing and treating esophageal cancer in Japan.

Geriatric Risk Prediction Models for Major Gastroenterological Surgery Using the National Clinical Database in Japan: A Multicenter Prospective Cohort Study.

OBJECTIVES: To investigate the effect of geriatric variables on 5 newly added outcomes and create risk models for predicting these outcomes. SUMMARY OF BACKGROUND DATA: Because there is a current lack of geriatric research focusing on geriatric outcomes using a national surgical database in Japan, there is a need to investigate outcomes associated with major gastro-enterological surgery using these data. METHODS: This multicenter prospective cohort study was conducted at 26 surgery departments across 21 institutions in Japan using the NCD surgical registry. in total, 22 new geriatric variables were imported from the ACS National Surgical Quality Improvement Program geriatric pilot study. The following 5 geriatric outcomes were defined: (1) postoperative delirium, (2) physical function on postoperative day 30, (3) fall risk on discharge, (4) discharge other than home with social service, and (5) functional decline on discharge, and geriatric risk prediction models for major gastroenterological surgery were created. RESULTS: Between January 2018 and December 2018, data on 3981 procedures from 7 major gastroenterological surgeries were collected and analyzed. Older age and preoperative geriatric variables (Origin status from home, History of dementia, Use of mobility aid, fall history, and not competent on admission) were strongly associated with postoperative outcomes. Geriatric risk prediction models for these outcomes were created, with C-statistic values ranging from 0.74 to 0.90, demonstrating model validity and sufficiency of fit. CONCLUSIONS: The risk models for the newly defined 5 geriatric outcomes that we created can be used in the decision-making process or provision of care in geriatric patients.

Total Synthesis of Alcyonolide.

The total synthesis of alcyonolide, an antitumor xenicn diterpenoid, has been achieved. The inverse electron demand hetero-Diels-Alder reaction using a dienophile possessing an electron-withdrawing group provided the endo adduct which included a condensed lactone and dihydropyran rings with the desired three stereogenic centers. After introduction of the side chain by the Negishi coupling, the lactone ring was opened to form a Weinreb amide. The sequential transformation including conversion of Weinreb amide to aldehyde, PMB to acetate, and allylation of the aldehyde gave a mixture of separable four diastereomers. The desired stereoisomer was submitted to the 2,2,6,6-tetramethylpiperidine 1-oxyl oxidation, which afforded the δ-lactone and the methyl ketone side chain. Finally, the olefin metathesis of the desired isomer gave racemic alcyonolide.

Report of the 22nd nationwide follow-up Survey of Primary Liver Cancer in Japan (2012-2013).

In the 22nd Nationwide Follow-up Survey of Primary Liver Cancer in Japan, data from 21 155 newly registered patients and 43 041 previously registered follow-up patients were compiled from 538 institutions over a 2-year period from January 1, 2012 to December 31, 2013. Basic statistics compiled for patients newly registered in the 22nd survey were cause of death, past medical history, clinical diagnosis, imaging diagnosis, treatment-related factors, pathologic diagnosis, recurrence status and autopsy findings. Compared with the previous 21st survey, the population of patients with hepatocellular carcinoma (HCC) was older at the time of clinical diagnosis, had more female patients, more patients with non-B non-C HCC, smaller tumor diameter and was more frequently treated with hepatectomy. Cumulative survival rates were calculated for HCC, intrahepatic cholangiocarcinoma, and combined hepatocellular cholangiocarcinoma (combined HCC and intrahepatic cholangiocarcinoma) by treatment type and background characteristics for patients newly registered between 2002 and 2013 whose final outcome was survival or death. Median overall survival and cumulative survival rates for HCC were calculated by dividing patients by combinations of background factors (number of tumors, tumor diameter or Child-Pugh grade) and by treatment type (hepatectomy, radiofrequency ablation therapy, transcatheter arterial chemoembolization, hepatic arterial infusion chemotherapy and systemic therapy). The same values were also calculated according to registration date by dividing patients newly registered between 1978 and 2013 into five time period groups. The data obtained from this nationwide follow-up survey are expected to contribute to advancing clinical research and treatment of primary liver cancer worldwide.

Comprehensive registry of esophageal cancer in Japan, 2014.

BACKGROUND: The registration committee for esophageal cancer in the Japan Esophageal Society (JES) has collected the patients' characteristics, treatment, and outcomes annually. METHODS: We analyzed the data of patients who had visited the participating hospitals in 2014. We collected the data with a web-based data collection system using the National Clinical Database. We used the Japanese Classification of Esophageal Cancer 10th edition by JES and the TNM classification 7th edition by the Union of International Cancer Control (UICC) for cancer staging. RESULTS: A total of 9026 cases were registered from 344 institutions in Japan. Squamous cell carcinoma and adenocarcinoma accounted for 87.9% and 7.1%, respectively. The 5-year survival rates of patients treated using endoscopic resection, concurrent chemoradiotherapy, radiotherapy alone, and esophagectomy were 87.1%, 33.7%, 25.3%, and 59.3%, respectively. Esophagectomy was performed in 5204 cases. Concerning the approach used for esophagectomy, 48.1% of the cases were treated thoracoscopically. The operative mortality (within 30 days after surgery) was 0.75%, and the hospital mortality was 2.0%. The survival curves showed an excellent discriminatory ability both in the clinical and pathologic stages by the JES system. The survival of pStage IV was better than IIIC in the UICC system, because pStage IV included the patients with supraclavicular lymph-node metastasis (M1 LYM). CONCLUSION: We hope that this report contributes to improving all aspects of diagnosing and treating esophageal cancer in Japan.

Surgically treated gastric cancer in Japan: 2011 annual report of the national clinical database gastric cancer registry.

BACKGROUND: The National Clinical Database (NCD) nationwide registry program of gastric cancer started in 2018. The purpose of this study was to report the treatment results of the NCD registry in the form of treatment results of the real world in Japan. METHODS: Patients' characteristics, tumor features, treatments, and outcomes were collected using a web-based data entry system. We analyzed the initial NCD database for data on surgically treated gastric cancer patients in 2011. RESULTS: A total of 30,257 patients with malignant gastric tumors were enrolled by the NCD registry program from 501 hospitals in all 47 prefectures. Of these, the status of data entry was not approved in 8.8% of the registered data, and follow-up information was missing in 1.2% of the approved cases. Excluding 1777 cases, which were not resected for primary gastric cancer, 25,306 resected cases included 44.4% of stomach surgeries recorded in the NCD. The 5 year survival rate of the resected cases was 71.3% and the operative mortality rate was 0.41%. The stage-specific 5 year survival rates were as follows: 89.6% for stage IA, 83.8% for stage IB, 77.3% for stage IIA, 69.1% for stage IIB, 58.7% for stage IIIA, 44.1% for stage IIIB, 30.1% for stage IIIC, and 13.4% for stage IV. CONCLUSIONS: The NCD gastric cancer registry program demonstrated validity for database construction. The gastric cancer registry is expected to become a nationwide registry with the dissemination of data entry system and method in the NCD.

Report of the 21st Nationwide Follow-up Survey of Primary Liver Cancer in Japan (2010-2011).

In the 21st Nationwide Follow-up Survey of Primary Liver Cancer in Japan, data from 22,134 new patients and 41,956 previously followed patients were compiled from 546 institutions over a 2-year period from 1 January 2010 to 31 December 2011. Basic statistics compiled for patients newly registered in the 21st survey were cause of death, medical history, clinical diagnosis, imaging diagnosis, treatment-related factors, pathological diagnosis, recurrence status, and autopsy findings. Compared with the previous 20th survey, the population of patients with hepatocellular carcinoma (HCC) was older at the time of clinical diagnosis, had more female patients, had more patients with non-B non-C HCC, had smaller tumor diameter, and was more frequently treated with hepatectomy and with radiofrequency ablation. Cumulative survival rates were calculated for HCC, intrahepatic cholangiocarcinoma, and combined hepatocellular cholangiocarcinoma (combined HCC and intrahepatic cholangiocarcinoma) by treatment type and background characteristics for patients newly registered between 1998 and 2011 whose final outcome was survival or death (excluding unknown). Cumulative survival rates for HCC were calculated by dividing patients by combinations of background factors (number of tumors, tumor diameter, and Child-Pugh grade) and by treatment type (hepatectomy, local ablation therapy, transcatheter arterial chemoembolization, and hepatic arterial infusion chemotherapy). The same values were also calculated according to registration date by dividing patients newly registered between 1978 and 2011 into four time-period groups. The data obtained from this nationwide follow-up survey are expected to contribute to advancing clinical research and treatment of primary liver cancer.

Estimates of the effects of centralization policy for surgery in Japan: does centralization affect the quality of healthcare for esophagectomies?

PURPOSE: This study compared the quality of healthcare before and after implementation of a policy restructuring the healthcare delivery system and estimated the impact of centralization. METHODS: We used the National Clinical Database to study patients undergoing esophagectomies from 2011 to 2016. We compared the effect of centralization based on the patient background, surgical mortality, and year of surgery. Difference-in-difference methods based on the generalized estimating equation logistic regression model were used for before-and-after comparisons after adjusting for patient-level expected surgical mortality. RESULTS: In total, 34,640 cases were identified. More cases with risk factors were noted in ultra-low-volume hospitals, where 38.4% of cases in underpopulated areas were treated, than in higher volume facilities, and the operative mortality, readmission within 30 days and length of stay were worse among patients treated in these hospitals. In centralized prefectures, the number of cases per hospital increased over time (7.2 in 2011 to 9.5 in 2016) while the crude operative mortality tended to decrease (3.4% in 2011 to 1.8% in 2016). The difference-in-difference estimator was 0.856 (95% confidence interval: 0.639-1.147, p = 0.298). CONCLUSION: The centralization of ultra-low-volume hospitals did not lead to a deterioration in the quality of care but rather an improving trend.

Comprehensive registry of esophageal cancer in Japan, 2013.

BACKGROUND: Esophageal cancer is the eighth most common cause of cancer mortality in Japan. More than 11,000 people had died from esophageal cancer in 2018. The Japan Esophageal Society has collected the data on patients' characteristics, performed treatment, and outcomes annually. METHODS: We analyzed the data of patients who had first visited the participating hospitals in 2013. In 2019, the data collection method was changed from an electronic submission to a web-based data collection using the National Clinical Database (NCD). Japanese Classification of Esophageal Cancer 10th by the Japan Esophageal Society (JES) and UICC TNM Classification 7th were used for cancer staging RESULTS: A total of 8019 cases were registered from 334 institutions in Japan. Squamous cell carcinoma and adenocarcinoma accounted for 87.8% and 6.3%, respectively. The 5-year survival rates of patients treated using endoscopic resection, concurrent chemoradiotherapy, radiotherapy alone, or esophagectomy were 88.3%, 32.4%, 24.4%, and 59.3%, respectively. Esophagectomy was performed in 4910 cases. The operative and the hospital mortality rates were 0.77% and 1.98%, respectively. The survival curves showed a good discriminatory ability both in the clinical and pathologic stages by the JES system. The 5-year survival rate of patients with pStage IV in the UICC classification that included patients with supraclavicular node metastasis was better than that of patients with pStage IVb in JES classification. CONCLUSION: We hope this report contributes to improving all aspects of the diagnosis and treatment of esophageal cancer in Japan.

Report of the 20th Nationwide follow-up survey of primary liver cancer in Japan.

In the 20th Nationwide Follow-up Survey of Primary Liver Cancer in Japan, data from 21 075 new patients and 40 769 previously followed patients were compiled from 544 institutions over a 2-year period from 1 January 2008 to 31 December 2009. Compared with the previous 19th survey, the population of patients with hepatocellular carcinoma (HCC) was older at the time of clinical diagnosis, included more female patients, included more patients with non-B non-C HCC, had smaller tumor diameters and more frequently received radiofrequency ablation as local ablation therapy. Cumulative survival rates were calculated for HCC, intrahepatic cholangiocarcinoma, and combined hepatocellular cholangiocarcinoma (combined HCC and intrahepatic cholangiocarcinoma) by treatment type and by background characteristics for patients newly registered between 1998 and 2009 whose final outcome was survival or death. Cumulative survival rates for HCC were calculated by dividing patients by combinations of background factors (number of tumors, tumor diameter, and Child-Pugh grade) and by treatment types (hepatectomy, local ablation therapy, and transcatheter arterial chemoembolization). Cumulative survival rates and median overall survival in patients treated by resection, transcatheter arterial chemoembolization, and local ablation therapy were calculated. The same values were also calculated by the registration date by dividing patients newly registered between 1978 and 2009 into four time period groups . The results of the analysis show that the prognosis of HCC is improving dramatically. It is expected that the data obtained from this nationwide follow-up survey will contribute to advancing clinical research, including the design of clinical trials, as well as the treatment strategy of primary liver cancer in the clinical practice setting.

Current status of projects for developing cancer-related clinical practice guidelines in Japan and recommendations for the future.

BACKGROUND: The current status and adoption of cancer-related clinical practice guidelines in Japan has not been elucidated yet. The purpose of this study was to propose roles and suggestions to develop future cancer-related clinical guidelines. METHODS: A questionnaire consisting of four domains with a total of 17 questions was developed. We distributed the questionnaire to 28 specific academic organizations in Japan which have developed any cancer-related clinical practice guidelines and which were funded by the Ministry of Health, Labor, and Welfare. RESULTS: Most organizations have investigated nationwide dissemination and adoption of clinical practice guidelines. The rate of adoption in clinical practice was estimated at approximately ≥ 70%. However, organizations with smaller budgets reported surveying approximately 60% of the time, whereas the ones with larger budgets reported approximately 100% success in surveying about their guidelines. The presidents of the organizations agreed that a new organization operated directly by the national government was necessary. CONCLUSION: In Japan, to develop cancer-related clinical practice guidelines, a study of clinical validation is necessary. Sufficient funds must be available to support the project to maintain and revise the guidelines. Furthermore, legal and ethical issues should be solved before establishing any registry system.

Evaluating the quality of data from the Japanese National Clinical Database 2011 via a comparison with regional government report data and medical charts.

PURPOSE: The aim of this study was to examine the quality of data from the National Clinical Database (NCD) via a comparison with regional government report data and medical charts. METHODS: A total of 1,165,790 surgical cases from 3007 hospitals were registered in the NCD in 2011. To evaluate the NCD's data coverage, we retrieved regional government report data for specified lung and esophageal surgeries and compared the number with registered cases in the NCD for corresponding procedures. We also randomly selected 21 sites for on-site data verification of eight demographic and surgical data components to assess the accuracy of data entry. RESULTS: The numbers of patients registered in the NCD and regional government report were 46,143 and 48,716, respectively, for lung surgeries and 7494 and 8399, respectively, for esophageal surgeries, leading to estimated coverages of 94.7% for lung surgeries and 89.2% for esophageal surgeries. According to on-site verification of 609 cases at 18 sites, the overall agreement between the NCD data components and medical charts was 97.8%. CONCLUSION: Approximately, 90-95% of the specified lung surgeries and esophageal surgeries performed in Japan were registered in the NCD in 2011. The NCD data were accurate relative to medical charts.

Initial verification of data from a clinical database of gastroenterological surgery in Japan.

PURPOSES: To evaluate the reliability of data collected from the gastroenterological section of the National Clinical Database of Japan (NCD), which began registrations in 2011 with ten surgical subspecialty societies. METHODS: During 2014 and 2015, 1,136,700 cases involving 115 procedures at 4374 hospitals were registered in the gastroenterological surgery section of the NCD. After a test audit using the 2014 data, 17 hospitals were selected for the first audit and data verification for 2015. The data accuracy of patient demographics, surgical outcomes, and processes was assessed using 45 items from the cases registered, in comparison with the medical records. RESULTS: In the first audit of the 2015 data, case registration accuracy verification involved 338 patients (99.4% of the extracted cases). The data accuracy with the maximum postoperative variables was > 95%. Accuracy of the mortality and status 30 days after the surgery was high (> 99%) with a sensitivity of 1.00 and a specificity of 1.00. Among the six complications studied, the recorded cases had high specificity but lower sensitivity (0.70-0.89). CONCLUSIONS: We verified the data from the gastroenterological section of the NCD and found high accuracy of data entry.

Saccular and Fusiform Abdominal Aortic Aneurysms Treated With Endovascular Repair Differ in Presentation and Treatment Threshold: Analyses Using a National Clinical Database in Japan.

BACKGROUND: Saccular abdominal aortic aneurysms (AAAs) are considered to be at higher risk of rupture than fusiform AAAs, but not much is known about the extent of this risk. Therefore, this study aimed to compare the rupture presentation between fusiform and saccular AAAs. METHODS AND RESULTS: This is a retrospective cohort study on 27 290 patients who underwent primary endovascular repair for a degenerative AAA between 2016 and 2019, and who were registered in the National Clinical Database in Japan. At operation for nonruptured case, the aneurysm diameter was significantly smaller in saccular AAAs than in fusiform AAAs (median, 44.0 versus 51.0 mm; P<0.001). Similarly, aneurysm diameter at rupture was significantly smaller in saccular AAAs than in fusiform AAAs (median, 55.6 versus 68.0 mm; P<0.001). The likelihood of repair for rupture was significantly higher in saccular AAAs than in fusiform AAAs in the 40- to 54-mm diameter range, in which saccular morphology was found to be an independent risk factor for rupture against fusiform morphology by adjusting for sex and aneurysm diameter (odds ratio, 2.54 [95% CI, 1.75-3.69]). In addition, receiver-operating characteristic curve analysis revealed that the cutoff diameter to predict rupture was smaller in saccular AAAs than in fusiform AAAs (50.5 and 59.5 mm, respectively) based on the Youden index. CONCLUSIONS: Saccular AAAs presented at smaller diameters than fusiform AAAs in patients with ruptured AAAs treated with endovascular aortic repair, which supports the idea that saccular AAAs should be treated at smaller diameters.