Published papers

Purpose: S-1, a novel oral prodrug of 5-fluorouracil (5-FU), and irinotecan with or without bevacizumab is known to be effective in metastatic colorectal cancer (mCRC). However, it is not clear whether S-1 and irinotecan confers benefits compared to 5-FU and leucovorin plus oxaliplatin (FOLFOX) in patients with mCRC. Our aim was to compare the efficacy and safety of these regimens. Methods: We analyzed 187 patients with previously untreated mCRC who were enrolled in four phase II studies: SIR (S-1 and irinotecan, n = 40), SIRB (S-1 and irinotecan with bevacizumab, n = 51), FOLFOX (5-FU and leucovorin plus oxaliplatin, n = 46), and STOX (stop-and-go strategy of modified FOLFOX-6 with bevacizumab, n = 50). We evaluated efficacy and safety between SIR/SIRB and FOLFOX/STOX. Results: Baseline characteristics were similar in the two groups composed of SIR/SIRB (n = 91) and FOLFOX/STOX (n = 96). The overall response rates were not significantly different between the two groups (65 % in SIR/SIRB vs. 52 % in FOLFOX/STOX, p = 0.125). The median progression-free survival was 10.9 months in SIR/SIRB versus 12.1 months in FOLFOX/STOX (p = 0.59). The median overall survival was 27.3 months in SIR/SIRB versus 26.8 months in FOLFOX/STOX (p = 0.97). Gastrointestinal adverse events were the most common toxicities in SIR/SIRB, while neutropenia and sensory neuropathy were the most common toxicities in FOLFOX/STOX. Conclusions: S-1 and irinotecan with or without bevacizumab was well tolerated and showed similar response rates and survival compared to the FOLFOX regimen. This combination should be considered as an experimental first-line treatment for mCRC.

BACKGROUND: Guillain-Barré syndrome (GBS) is an immune-mediated neuropathy that causes acute flaccid paralysis. Immunoglobulin and plasma exchange are established treatments for GBS; however, a substantial number of patients, particularly those with severe disease, have poor recovery and residual deficits. Recent studies suggest that complement activation plays a pivotal role in GBS-associated axonal degeneration, and eculizumab is a humanized monoclonal antibody that specifically binds to complement component 5 and potently inhibits complement activation. OBJECTIVE: This clinical trial aims to evaluate the efficacy and safety of eculizumab, a humanized monoclonal antibody directed against complement component 5, for treatment of GBS. METHODS: The Japanese Eculizumab Trial for GBS (JET-GBS) is a prospective, multicenter, placebo-controlled, double-blind, randomized phase II study conducted at 13 tertiary neurology centers and is funded by the Japan Agency for Medical Research and Development. A total of 33 GBS patients unable to walk independently within 2 weeks from symptom onset (Hughes functional grade 3-5) were randomized at a 2:1 ratio to receive either intravenous eculizumab (900 mg/day) or placebo once weekly for 4 weeks, followed by 20 weeks of follow-up. The primary endpoint for efficacy is the proportion of patients who regain their ability to walk without aid at 4 weeks after the first dose of the study treatment, while primary safety outcomes are the incidence of adverse events and serious adverse events during the trial. RESULTS: Enrollment for the trial began in August 2015. This trial is still ongoing. All participants have been enrolled, and follow-up will be completed in October 2016. CONCLUSIONS: This study is the first to investigate the efficacy and safety of eculizumab for GBS. In case of a positive result, we will plan a phase III trial to investigate this issue in a larger number of patients. CLINICALTRIAL: UMIN Clinical Trials Registry UMIN 000018171; https:/upload.umin.ac.jp/cgi-open-bin/ctr/ctr.cgi?function= brows&action=brows&type=summary&language=J&recptno=R000020978 (Archived by WebCite at http://www.webcitation.org/ 6lTiG8ltG). Clinical Trials.gov NCT02493725; https://clinicaltrials.gov/ct2/show/NCT02493725 (Archived by WebCite at http://www.webcitation.org/6lVJZXKSL).

Introduction: Fluoropyrimidine plus platinum (FP)-based chemotherapy has been widely used as a first-line regimen for advanced or recurrent esophageal cancer, and taxanes have shown efficacy after FP-based chemotherapy, but there is no standard regimen for second-line chemotherapy (SLC). We retrospectively investigated the clinical features of taxane therapy in SLC for esophageal squamous cell carcinoma (ESCC). Methods: The selection criteria were pathologically proven ESCC; advanced or recurrent disease previously treated with FP at our hospital; performance status (PS) 0-2; and adequate organ function. Docetaxel (DTX) was administered 3-weekly at 70 mg/m2. Paclitaxel (PTX) was administered at 100 mg/m2 weekly for 6 weeks, with 1 week's rest. Results: The analysis covered 163 patients from August 2006 to June 2012. Median age was 64 years (range 37-83: DTX group 132 patients and PTX group 31). Progression-free survival and median overall survival (OS) were 2.3 and 6.1 months, respectively, with PTX and 2.3 and 5.3 months with DTX. Response rates were 20.7 % for PTX and 5.9 % for DTX. The rate of grades 3-4 neutropenia was higher with DTX (32.6 %) than with PTX (16.1 %). Grade 3 febrile neutropenia was seen in 6.1 % of DTX recipients but in no PTX group. According to multivariate analyses of OS, PS 2, number of metastatic sites 2, and CRP 1 mg/dL were independent predictors of poor prognosis. Conclusions: PTX and DTX were both effective in SLC for ESCC, but their toxicity profiles differed. In terms of febrile neutropenia, PTX seems more appropriate.

Skin toxicity is a known clinical signature used to predict the prognosis of anti-epidermal growth factor receptor (EGFR) antibody treatment in metastatic colorectal cancer (mCRC). There are no biological markers to predict skin toxicity before anti-EGFR antibody treatment in mCRC patients. Between August 2008 and August 2011, pretreatment serum samples were obtained from KRAS wild-type (WT) patients who received anti-EGFR antibody treatment. Serum levels of ligands were measured by ELISA. A total of 103 KRAS WT patients were enrolled in the study. Progression-free survival and overall survival of patients with a high grade (grade 2-3) of skin toxicity were significantly longer than those with a low grade (grade 0-1) of skin toxicity (median progression-free survival, 6.4 months vs 2.4 months, P < 0.001; median overall survival, 14.6 months vs 7.1 months, P = 0.006). There were significant differences in distribution of serum levels of epiregulin (EREG), amphiregulin (AREG), and hepatocyte growth factor (HGF) between groups of low/high grade of skin toxicity (P < 0.048, P < 0.012, P < 0.012, respectively). In addition, serum levels of HGF, EREG, and AREG were inversely proportional to grades of skin toxicity as determined by the Cochran-Armitage test (P = 0.019, P = 0.047, P = 0.021, respectively). Our study indicated that serum levels such as HGF, EREG, and AREG may be significant markers to predict the grade of skin toxicity and the prognosis of anti-EGFR antibody treatment, which contribute to improvement of the management of skin toxicity and survival time in mCRC patients.

Background: While the standard treatment for stage II–III (non-T4) esophageal squamous cell carcinoma (ESCC) is neoadjuvant therapy followed by esophagectomy, definitive chemoradiation therapy (dCRT) is an option to treat ESCC patients who reject or may not tolerate surgical treatment. Second primary malignancy (SPM) is a problem for long-term survivors after achieving complete response (CR) by dCRT. Methods: The source of the subjects in this study was the patients with stage II/III (excluding T4 disease) ESCC (UICC6th) who underwent dCRT from 2000 to 2011 at the National Cancer Center Hospital, Japan. SPM, defined as malignancy newly detected at different site from the initial disease, was checked in patients who achieved CR by the initial dCRT. Results: Among the 285 patients with stage II/III (excluding T4 disease) ESCC who underwent dCRT, 185 patients achieved CR. SPM was detected in 49 patients (median time to developing SPM, 41.5 months), accounting for 19.3% (95% CI 0.137–0.257) as the 5-year cumulative risk of SPM. SPMs were head and neck cancer (n = 12), gastric cancer (n = 12), esophageal cancer (n = 7), lung cancer (n = 5), colon cancer (n = 4), diffuse large B-cell lymphoma (n = 3), bladder cancer (n = 2), small intestinal cancer (n = 1), cholangiocarcinoma (n = 1), malignant melanoma (n = 1), and breast cancer (n = 1). There were no significant differences in baseline characteristics between the patients who developed SPM (n = 49) and others (n = 136). Conclusions: Because second primary malignancy developed often after achieving CR by dCRT for ESCC, it should be followed carefully.

What is known and objective: Study design and statistical methods have become core components of medical research, and the methodology has become more multifaceted and complicated over time. The study of the comprehensive details and current trends of study design and statistical methods is required to support the future implementation of well-planned clinical studies providing information about evidence-based medicine. Our purpose was to illustrate study design and statistical methods employed in recent medical literature. Methods: This was an extension study of Sato et al. (N Engl J Med 2017; 376: 1086-1087), which reviewed 238 articles published in 2015 in the New England Journal of Medicine (NEJM) and briefly summarized the statistical methods employed in NEJM. Using the same database, we performed a new investigation of the detailed trends in study design and individual statistical methods that were not reported in the Sato study. Results and discussion: Due to the CONSORT statement, prespecification and justification of sample size are obligatory in planning intervention studies. Although standard survival methods (eg Kaplan-Meier estimator and Cox regression model) were most frequently applied, the Gray test and Fine-Gray proportional hazard model for considering competing risks were sometimes used for a more valid statistical inference. With respect to handling missing data, model-based methods, which are valid for missing-at-random data, were more frequently used than single imputation methods. These methods are not recommended as a primary analysis, but they have been applied in many clinical trials. Group sequential design with interim analyses was one of the standard designs, and novel design, such as adaptive dose selection and sample size re-estimation, was sometimes employed in NEJM. What is new and conclusion: Model-based approaches for handling missing data should replace single imputation methods for primary analysis in the light of the information found in some publications. Use of adaptive design with interim analyses is increasing after the presentation of the FDA guidance for adaptive design.

Background: Despite the introduction of plasmapheresis and immunoglobulin therapy, many patients with Guillain-Barré syndrome still have an incomplete recovery. Evidence from pathogenesis studies suggests the involvement of complement-mediated peripheral nerve damage. We aimed to investigate the safety and efficacy of eculizumab, a humanised monoclonal antibody against the complement protein C5, in patients with severe Guillain-Barré syndrome. Methods: This study was a 24 week, multicentre, double-blind, placebo-controlled, randomised phase 2 trial done at 13 hospitals in Japan. Eligible patients with Guillain-Barré syndrome were aged 18 years or older and could not walk independently (Guillain-Barré syndrome functional grade 3–5). Patients were randomly assigned (2:1) to receive 4 weeks of intravenous immunoglobulin plus either eculizumab (900 mg) or placebo; randomisation was done via a computer-generated process and web response system with minimisation for functional grade and age. The study had a parallel non-comparative single-arm outcome measure. The primary outcomes were efficacy (the proportion of patients with restored ability to walk independently [functional grade ≤2] at week 4) in the eculizumab group and safety in the full analysis set. For the efficacy endpoint, we predefined a response rate threshold of the lower 90% CI boundary exceeding 50%. This trial is registered with ClinicalTrials.gov, number, NCT02493725. Findings: Between Aug 10, 2015, and April 21, 2016, 34 patients were assigned to receive either eculizumab (n=23) or placebo (n=11). At week 4, the proportion of the patients able to walk independently (functional grade ≤2) was 61% (90% CI 42–78; n=14) in the eculizumab group, and 45% (20–73; n=5) in the placebo group. Adverse events occurred in all 34 patients. Three patients had serious adverse events: two in the eculizumab group (anaphylaxis in one patient and intracranial haemorrhage and abscess in another patient) and one in the placebo group (depression). The possibility that anaphylaxis and intracranial abscess were related to eculizumab could not be excluded. No deaths or meningococcal infections occurred. Interpretation: The primary outcome measure did not reach the predefined response rate. However, because this is a small study without statistical comparison with the placebo group, the efficacy and safety of eculizumab could be investigated in larger, randomised controlled trials. Funding: The Japan Agency for Medical Research and Development, Ministry of Health, Labor and Welfare, and Alexion Pharmaceuticals.

Nicorandil has vasodilatory effects on both the epicardial coronary arteries and the coronary microvasculature, thereby increasing coronary blood flow. The objective of the present study was to investigate the effectiveness of intravenous (IV) nicorandil infusion for fractional flow reserve (FFR) measurement. In this crossover randomized study, 49 patients underwent FFR measurement with a consecutive randomized order of patient-blind infusions of continuous IV adenosine administration and a single bolus IV administration of nicorandil. The primary endpoint was the difference between the FFR by nicorandil and the FFR by adenosine, as assessed by the Bland–Altman method. The mean FFR value measured by nicorandil was not significantly different from that measured by adenosine [0.8125 ± 0.1349 vs. 0.7978 ± 0.124; mean difference, 0.0147 (95% confidence interval − 0.0373, 0.0667); P = 0.58]. There was no clinically significant diagnostic discordance, with the FFR by nicorandil > 0.80 and that by adenosine < 0.75. Hyperemia was achieved earlier using nicorandil than adenosine (34 ± 13 vs. 58 ± 15, P < 0.001). The duration of hyperemia after IV nicorandil was variable (6–570 s, mean 89 ± 98 s). IV nicorandil decreased systolic blood pressure by 32 ± 16 mm Hg (24 ± 10%) from baseline. Linear regression analysis showed that the average FFR value and the difference in systolic blood pressure were significantly associated with the bias in the FFR value between the two drugs. In conclusions, the results of the present study suggest that IV nicorandil can achieve maximal hyperemia easily and rapidly, providing an acceptable diagnostic performance for FFR assessment. However, a wide range of variation in hyperemic plateau and a decrease in blood pressure are the major limitations of this method.

Objective: We aimed to reveal the association between body mass index (BMI) and medical costs in the current Japanese population, and to estimate the population attributable fraction (PAF) of medical costs due to overweight and obesity. Methods: A generalized linear mixed model with log link function and gamma distribution was used to evaluate the association between BMI and medical costs in 34,537 beneficiaries of the National Health Insurance aged 40–69 years in Chiba City. Medical cost data were obtained from insurance claims submitted between April 2012 and March 2016. PAFs due to overweight (BMI ≥25.0 and <30.0 kg/m ) and obesity (BMI ≥30.0 kg/m ) were calculated. Results: Overweight and obesity were significant predictors of excessive medical costs in all age and sex groups. PAF due to overweight and obesity was estimated to be 9.62% (95% confidence interval, 8.52–10.73%). Additionally, PAFs in 40–59-year-old individuals (12.76% in men and 11.63% in women) were greater than those in 60–69-year-old subjects (6.55% in men and 7.80% in women) for both sexes. Conclusions: In the Japanese population, overweight and obesity are an excessive financial burden with an estimated PAF of 9.62% of total medical costs. 2 2

Study Objectives: The WatchPAT is a wrist-worn portable device that creates integration data regarding peripheral arterial tone (PAT), oxyhemoglobin saturation, heart rate, and actigraphy to diagnose or screen for obstructive sleep apnea (OSA). Previous studies have demonstrated the efficacy and validity of respiratory variables measured by the WatchPAT compared to those using polysomnography (PSG). However, the effects of arterial stiffness or atherosclerosis on WatchPAT parameters remain to be elucidated. Methods: Sixty-one consecutive patients with suspected OSA who underwent home-based testing with the WatchPAT 200, standard in-laboratory overnight polysomnography (PSG), and pulse wave velocity (PWV) as an index of arterial stiffness were studied. All PSG recordings were scored manually using the American Academy of Sleep Medicine criteria, whereas WatchPAT data were analyzed by an automatic algorithm. We evaluated how arterial stiffness affected respiratory event index data in WatchPAT (WP-AHI), because WP-AHI could be partly influenced by PAT, comparing WP-AHI and the apneahypopnea index measured by PSG (PSG-AHI) in consideration of PWV result. Results: Overall, WP-AHI was moderately correlated to PSG-AHI, but WP-AHI was significantly lower than PSG-AHI (28.4 ± 19.2 versus 53.6±30.2 events/h, P<.0001). For the lower PWV group, there was a significant correlation and good agreement between the WP-AHI and PSG-AHI, but as the PWV increased, there was low correlation between the WP-AHI and PSG-AHI. Conclusions: Arterial stiffness may affect the respiratory variables measured by WatchPAT in patients with OSA.

objective: Peritoneal metastasis (PM) is the most frequent form of metastasis in gastric cancer (GC). The sensitivity of detecting PM by pre-operative imaging modalities is low. Utility of positron emission tomography (PET) with F-fluodeoxyglucose (FDG) for GC is limited, because diffuse-type tumors are not FDG-avid. F-fluothymidine ([F-18]FLT) is a radiotracer that reflects cellular proliferation and the utility of [F-18] FLT-PET in GC has been reported. In this proof-of-concept study, we explored the ability of [F-18]FLT-PET/CT to detect PM of GC previously identified by other imaging modalities. methods: The key eligibility criteria were as follows; (i) histologically proven gastric adenocarcinoma; (ii) evident PM detected by CT performed within 4 weeks prior to registration; (iii) no prior treatment of PM within 4 weeks before registration. [F-18]FLT-PET/CT was performed at National Cancer Center Hospital, and [F-18]FLT-PET/CT images were evaluated independently by two radiologists. Safety assessments were carried out before and after [F-18]FLT-PET/CT. The primary end point was the detection sensitivity of PM. results: A total of 19 eligible patients were analyzed, of which 15 (78.9%) had diffuse-type histology. Detection sensitivity of PM, primary lesion, and lymph node metastasis were 73.7% [maximum standardized uptake value (SUVmax): 1.697-13.21], 100% (SUVmax: 2.71-22.01), and 72.7% (SUVmax: 2.079-12.61), respectively. No patients experienced adverse events during or after [F-18] FLT-PET/CT. conclusion: This proof-of-concept study shows that [F-18]FLT-PET/CT is a sensitive method for detecting PM in GC, and paves the way for future studies investigating the clinical utility of this approach for the detection of clinically non-evident PM in GC. 18 18

This study aimed to determine the incidence and risk factors for hepatitis B virus (HBV) reactivation in patients with rheumatoid arthritis (RA) undergoing immunosuppressive therapy. The National Database of Japan, in which insurance claim data have been comprehensively accumulated, was utilized. The subjects were 76 641 RA patients who were plausibly initiated on immunosuppressive therapy from April 2013 to March 2014. Laboratory tests of the hepatitis B surface antigen, anti-hepatitis B virus surface antibody, and anti-hepatitis B virus core antibody were performed in 28.23%, 12.52% and 14.63% of patients, respectively, when the therapy was initiated. We found that HBV reactivation and fulminant hepatitis occurred in both the patients with and without HBV DNA monitoring, indicating insufficient monitoring in Japan during the study. The cumulative incidence of HBV reactivation over 24 months was 1.57% (95% confidence interval [CI] = 1.28%-1.92%) in the monitoring group, which consisted of those with resolved HBV infection. Glucocorticoid administration was a potent risk factor for HBV reactivation (hazard ratio [HR] = 1.70, 95% CI = 1.26-2.29, P =.001 in all subjects, and HR = 1.82, 95% CI = 1.18-2.81, P =.007 in the nonmonitoring group), although it was not statistically significant in the monitoring group (HR = 1.49, 95% CI = 0.99-2.26 and P =.057). No significant risk difference was observed between single administration of methotrexate and biological drugs.

Objective Although severe obstructive sleep apnea (OSA) is an important risk factor for atherosclerosis-related diseases including coronary artery disease (CAD), there is no reliable biomarker of CAD risks in patients with OSA. This study aimed to test our hypothesis that circulating autoantibodies against neuroblastoma suppressor of tumorigenicity 1 (NBL1-Abs) are associated with the prevalence of CAD in patients with OSA. Methods Eighty-two adults diagnosed with OSA by polysomnography, 96 patients with a diagnosis of acute coronary syndrome (ACS) and 64 healthy volunteers (HVs) were consecutively enrolled. Serum samples were collected from patients with OSA at diagnostic polysomnography and from patients with ACS at disease onset. Serum NBL1-Ab level was measured by amplified luminescence proximity homogeneous assay and its association with clinical variables related to atherosclerosis was evaluated. Results NBL1-Ab level was significantly elevated in patients with both OSA and ACS compared with HVs. Subgroup analyses showed that NBL1-Ab level was markedly higher in patients with severe OSA and OSA patients with a history of CAD. Weak associations were observed between NBL1-Ab level and apnea-hypopnea index, age, mean SpO and arousal index, whereas significantly higher NBL1-Ab levels were observed in OSA patients with a history of CAD than in those without a history of CAD. Sensitivity analysis using a logistic regression model also demonstrated that increased NBL1-Ab levels were associated with the previous history of CAD in patients with OSA. Conclusions Elevated NBL1-Ab levels may be associated with the prevalence of CAD in patients with OSA, which needs to be confirmed further. 2

Objective To assess the cerebral blood flow (CBF) in patients with diabetic neuropathic pain, and its changes after duloxetine therapy. Methods Using iodine-123-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (IMP-SPECT), we performed a cross-sectional study of 44 patients with diabetes, and compared CBF in those with (n = 24) and without neuropathic pain (n = 20). In patients with neuropathic pain, we also longitudinally assessed changes in CBF 3 months after treatment with duloxetine. Results IMP-SPECT with voxel-based analyses showed a significant increase in cerebral blood flow in the right anterior cingulate cortex and a decrease in the left ventral striatum in patients with neuropathic pain, compared with those without pain. After duloxetine treatment, volume of interest analyses revealed a decrease in cerebral blood flow in the anterior cingulate cortex in patients with significant pain relief but not in non-responders. Furthermore, voxel-based whole brain correlation analyses demonstrated that greater baseline CBF in the anterior cingulate cortex was associated with better pain relief on the numerical rating scale. Conclusions Our results suggest that the development of neuropathic pain is associated with increased activity in the anterior cingulate cortex, and greater baseline activation of this region may predict treatment responsiveness to pharmacological intervention. Trial registration number UMIN000017130;Results.

Background: A combination of S-1 and cisplatin is recognized as one of the standard first-line chemotherapy regimens for patients with advanced gastric cancer. However, demographic analyses of pivotal phase III studies have showed that only a minority of treated patients were aged 76 years or older. The purpose of this phase II study was to evaluate the safety and efficacy of combination therapy with S-1 and cisplatin in elderly patients with chemotherapy-naive advanced gastric cancer. Methods: Patients aged 76 years or older received S-1 40 mg/m orally twice daily for 21 days and cisplatin 60 mg/m intravenously infused at day 8 of each 35-day cycle. Dose modification was performed according to creatinine clearance. The primary endpoint was overall survival (OS). Secondary endpoints included response rate, progression-free survival (PFS), time to treatment failure (TTF), and adverse events. Results: A total of 40 patients were enrolled. Median OS was 12.3 months, PFS was 7.8 months, and TTF was 4.3 months. The response rate was 54%. The most common grade 3–4 adverse events were anorexia (25%), neutropenia (23%), hyponatremia (20%), anemia (18%), and febrile neutropenia (8%). No treatment-related death occurred. Conclusions: Combination chemotherapy with S-1 and cisplatin is an effective and well-tolerated regimen for elderly patients with advanced gastric cancer when the dose is adjusted according to renal function. 2 2

Purpose: The aim of this phase II study was to evaluate the efficacy and safety of two doses (10 and 5 mg) of olanzapine in combination with standard antiemetic treatment (aprepitant, palonosetron, and dexamethasone) for patients receiving highly emetogenic chemotherapy (HEC). Methods: A multi-institutional, double-blind, randomized phase II, dose-finding study of olanzapine was performed in patients with a malignant solid tumor who were receiving HEC with cisplatin (≥ 50 mg/m ). Patients were randomly assigned either olanzapine 10 or 5 mg orally on days 1–4, combined with standard antiemetic treatment. The primary endpoint was a complete response (CR; no emesis and no use of rescue medications) in the delayed phase (24–120 h after the start of cisplatin treatment). Results: 153 patients were randomized to the 10 mg group (n = 76) or the 5 mg group (n = 77). The CR rate in the delayed phase was 77.6% (80% CI: 70.3–83.8, P = 0.01) in the 10 mg group and 85.7% (80% CI: 79.2–90.7, P < 0.001) in the 5 mg group (P value for H : complete response rate ≤ 65%). The most common adverse event was somnolence, which had an incidence of 53.3 and 45.5% in the 10 and 5 mg olanzapine groups, respectively. Conclusions: Both doses of 10 and 5 mg olanzapine provided a significant improvement in delayed emesis. A dose of 5 mg olanzapine was determined as the recommended dose for a further phase III study based on higher CR and lower somnolence rates. Clinical Trial Information: UMIN000014214. 2 0

BACKGROUND: The 6-min walk test (6MWT) is commonly performed to assess functional status in patients with chronic thromboembolic pulmonary hypertension. However, changes in heart rate and oxygen saturation (S ) patterns during 6MWT in patients with chronic thromboembolic pulmonary hypertension remain unclear. METHODS: Thirty-one subjects with chronic thromboembolic pulmonary hypertension were retrospectively evaluated to examine the relationships between the change in heart rate (Δheart rate), heart rate acceleration time, slope of heart rate acceleration, heart rate recovery during the first minute after 6MWT (HRR1), change in S (ΔS ), S reduction time, and S recovery time during 6MWT, and the severity of pulmonary hemodynamics assessed by right heart catheterization and echocardiography. RESULTS: Subjects with severe chronic thromboembolic pulmonary hypertension had significantly longer heart rate acceleration time (144.9 ± 63.9 s vs 96.0 ± 42.5 s, P = .033), lower Δheart rate (47.4 ± 16.9 vs 61.8 ± 13.6 beats, P = .02), and lower HRR1 (13.3 ± 9.0 beats vs 27.1 ± 9.2 beats, P < .001) compared to subjects with mild chronic thromboembolic pulmonary hypertension. Subjects with severe chronic thromboembolic pulmonary hypertension also had significantly longer S reduction time (178.3 ± 70.3 s vs 134.3 ± 58.4 s, P = .03) and S recovery time (107.6 ± 35.3 s vs 69.8 ± 32.7 s, P = .004) than did subjects with mild chronic thromboembolic pulmonary hypertension. Multivariate linear regression analysis showed only mean pulmonary arterial pressure independently was associated with heart rate acceleration time and slope of heart rate acceleration. CONCLUSIONS: Heart rate and S change patterns during 6MWT are predominantly associated with pulmonary hemodynamics in subjects with chronic thromboembolic pulmonary hypertension. Evaluating heart rate and S change patterns during 6MWT may serve as a safe and convenient way to follow the change in pulmonary hemodynamics. pO2 pO2 pO2 pO2 pO2 pO2 pO2 pO2 pO 2