Kenji Okumura

Dr. Kenji Okumura

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Research Focus & Metrics

Academic Career Length

37Years (1990-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 August 2022 in Transplant Infectious Disease
Verified
Journal Article
Closed access
ADAbhay Dhand
Abhay Dhand
KOKenji Okumura
Kenji Okumura
CNChristopher Nabors
Christopher Nabors
SNSeigo Nishida
Seigo Nishida

1 April 2023 in Circulation: Heart Failure
Verified
Journal Article
Closed access
SOSuguru Ohira
Suguru Ohira
KOKenji Okumura
Kenji Okumura
SPStephen Pan
Stephen Pan
ADAbhay Dhand
Abhay Dhand
ELElliot Levine
Elliot Levine
MKMasashi Kai
Masashi Kai
Background: The impact of the new heart allocation policy, which prioritizes acutely ill patients on temporary mechanical circulatory support and provides broader sharing of donor organs, on patient and graft survival in combined heart and kidney transplantation (HKT) is unknown. Methods: In the United Network for Organ Sharing data, patients were divided in groups before and after the policy change (OLD, January 1, 2015 to October 17, 2018, N=533; and NEW, October 18, 2018 to December 31, 2020, N=370). Propensity score matching was performed utilizing recipient characteristics (283 pairs). The median follow-up was 1099 days. Results: The annual volume of HKT increased approximately 2-fold during this period (N=117 in 2015 and N=237 in 2020), predominantly among patients not on hemodialysis at time of transplantation. Ischemic times for heart (OLD, 2.94 versus NEW, 3.37 hours; P <0.001) and kidney grafts (14.1 versus 16.0 hours; P <0.001) were longer under the new policy, as was the travel distance (47 versus 183 miles; P <0.001). In the matched cohort, 1-year overall survival (OLD, 91.1% versus NEW, 84.8%; P <0.001), and freedom from heart and kidney graft failure rate were worse under the new policy. Patients not on hemodialysis at time of HKT demonstrated worse survival and a higher risk of kidney graft failure under the new policy compared with the old policy. In multivariate Cox proportional-hazards analysis, the new policy was associated with an increased risk of mortality (hazard ratio, 1.81; P =0.007), and graft failure among HKT recipients (heart, hazard ratio, 1.81; P =0.007; and kidney, hazard ratio, 1.83; P =0.002). Conclusions: The new heart allocation policy was associated with worse overall survival and decreased freedom from heart and kidney graft failure in HKT recipients.

26 July 2019 in BMC Nephrology
Verified
Journal Article
Open access
PDF file
KOKenji Okumura
Kenji Okumura
SYShigeyoshi Yamanaga
Shigeyoshi Yamanaga
KTKosuke Tanaka
Kosuke Tanaka
KKKohei Kinoshita
Kohei Kinoshita
AKAkari Kaba
Akari Kaba
HYHiroshi YOKOMIZO
Hiroshi YOKOMIZO
Compensation of contralateral kidney function after living-donor kidney donation is well known, and many predictive factors have been proposed. However, no prediction model has been proposed. This study was performed to establish a tool with which to estimate the degree of compensation of the contralateral kidney after living-donor kidney donation. We retrospectively analyzed 133 living donors for renal transplantation in our institution. We defined a favorable compensation as a post-donation estimated glomerular filtration rate (eGFR) at 1 year (calculated by the Chronic Kidney Disease Epidemiology Collaboration equation) of > 60% of the pre-donation eGFR. We analyzed the living donors’ clinical characteristics and outcomes. The median (range) donor age was 59 (24–79) years, median (range) body mass index was 22.9 (16.8–32.7) kg/m2, and median (range) body surface area was 1.6 (1.3–2.0) m2. All donors were Japanese, and 73% of the donors were biologically related. The median (range) donor pre-donation eGFR was 108.7 (82–144) ml/min/1.73 m2, and the median (range) post-donation eGFR at 1 year was 86.9 (43–143) ml/min/1.73 m2. Eighty-six percent of donors had compensatory hypertrophy. In the univariate analysis, age, female sex, history of hypertension, body surface area, and pre-donation eGFR were significantly associated with hypertrophy (p < 0.05). In the multivariate analysis, age, female sex, history of hypertension, and ratio of the remnant kidney volume to body weight were significantly associated with hypertrophy (p < 0.05). Based on these results, we created a compensation prediction score (CPS). The median (range) CPS was 8.7 (1.1–17.4). Receiver operating characteristic analysis showed strong diagnostic accuracy for predicting favorable compensation (area under the curve, 0.958; 95% confidence interval, 0.925–0.991, p < 0.001). The optimal cut-off value of the CPS was 5.0 (sensitivity, 92.0%; specificity, 89.5%). The CPS had a strong positive correlation with the post-donation eGFR (R = 0.797, p < 0.001). The CPS might be useful tool with which to predict a favorable compensation of the contralateral kidney and remnant kidney function. If the CPS is low, careful management and follow-up might be necessary. Further investigations are needed to validate these findings in larger populations.

5 October 2011 in Journal of Medical Case Reports
Verified
Journal Article
Open access
PDF file
KOKenji Okumura
Kenji Okumura
FSFumihiro Shoji
Fumihiro Shoji
MYMasaki Yoshida
Masaki Yoshida
AMAtsushi Mizuta
Atsushi Mizuta
IMIchiro Makino
Ichiro Makino
HHHidefumi Higashi
Hidefumi Higashi
Aeromonas species do not commonly cause disease in humans. However, when disease is seen, it often occurs in patients with underlying immunosuppression or malignancy and has a high fatality rate.

1 January 2016 in International Journal of Surgery Case Reports
Verified
Journal Article
Open access
JKJiro Kimura
Jiro Kimura
KOKenji Okumura
Kenji Okumura
HKHideki Katagiri
Hideki Katagiri
Alan LeforAlan Lefor
Alan Lefor
KMKen Mizokami
Ken Mizokami
TKTadao Kubota
Tadao Kubota
Omental hemorrhage results from rupture of the omental vessels. There are many causes of omental hemorrhage including trauma, aneurysm, and vasculitis. Idiopathic omental hemorrhage is a rare cause of an acute abdomen, which is potentially life-threatening. We report a patient with idiopathic omental hemorrhage, which may have been caused by overeating. A 29-year-old man without a history of trauma, bleeding disorders, or other significant medical history, presented with left upper quadrant pain, which began after overeating the previous evening. The pain worsened and he presented to the emergency department. On physical examination, his BP was 111/69mmHg and pulse 71 and he reported tenderness and involuntary guarding in the left upper quadrant on palpation. Contrast enhanced computed tomography scan revealed intraperitoneal fluid collection with intra-omental extravasation. Significant intraperitoneal hemorrhage was suspected and emergency laparotomy was performed. On exploring the abdominal cavity, a hematoma was found in the greater omentum, adjacent to the right gastroepiploic artery. No active bleeding was seen, and partial omentectomy was performed. There were no obvious lesions suggestive of malignancy or aneurysm, supporting the diagnosis of idiopathic omental hemorrhage. On postoperative day six, the patient developed a wound dehiscence, which was surgically closed. The subsequent postoperative course was uneventful and he was discharged on fifth day after the second operation. Idiopathic omental hemorrhage is a rare cause of an acute abdomen, which may develop after eating. Omentectomy is preferred to ligation or transcatheter arterial embolization to rule out an underlying malignancy or aneurysm.

5 July 2024 in Transplantation Direct
Verified
Journal Article
Open access
KOKenji Okumura
Kenji Okumura
ADAbhay Dhand
Abhay Dhand
RMRyosuke Misawa
Ryosuke Misawa
HSHiroshi Sogawa
Hiroshi Sogawa
GVGregory Veillette
Gregory Veillette
SNSeigo Nishida
Seigo Nishida
Background.: Use of normothermic machine perfusion (NMP) may help to expand the liver transplantation (LT) donor pool by potentially increasing the utilization of donation after circulatory death (DCD) organs. The aim of this study was to assess the impact of NMP on LT from DCD organs. Methods.: Data among DCD adult LT recipients in the United Network for Organ Sharing between January 2016 and December 2022 were analyzed. Outcomes were compared between 2 groups: NMP versus non-MP using propensity score matching. Results.: During the study period, 4217 DCD LT recipients (NMP: 257 and non-MP: 3960) were identified. compared with non-MP, DCD LT recipients in NMP group were older (median recipient age: 61 versus 59 y, P = 0.013), had lower model for the end-stage liver disease score, longer wait time (126 versus 107 d, P = 0.028), and received organs from older donors (median age: 42 versus 38 y, P < 0.01) with longer preservation time (9.9 versus 5.3 h, P < 0.001). Two-year overall survival (NMP 94.4% versus non-MP 89.7%, P = 0.040) and 2-y graft survival (NMP 91.3% versus non-MP 84.6%, P = 0.017) were better in the NMP group. After propensity score matching, 2-y overall survival (NMP 94.2% versus non-MP 88.0%, P = 0.023) and graft survival (NMP 91.3% versus non-MP 81.6%, P = 0.004) were better in the NMP group. On multivariable cox regression analysis, NMP was an independent factor of protection against mortality (hazard ratio, 0.43; 95% confidence interval: 0.20-0.91; P = 0.029) and against graft failure (hazard ratio, 0.26; 95% confidence interval: 0.11-0.61; P = 0.002). Conclusions.: Use of NMP for LT from DCD donors was associated with improved posttransplant patient and graft survival.