Digestive Diseases Research

Hemostasis Research

Research group

  • GI Hemostasis Research Group
Dennis M. Jensen, MD

Principal investigator

  • Dennis M. Jensen, MD

Co-investigators

  • UCLA and West Los Angeles VA Medical Center
    • Gareth Dulai, MD, MSHS
    • Jeffrey Gornbein, DrPH
    • Noam Jacob, MD, PhD
    • Stephen Kim, MD
    • Michael Lewis, MD
    • Hanlin Wang, MD, PhD
  • Harbor-UCLA Medical Center
    • Rome Jutabha, MD
  • Olive View-UCLA Medical Center
    • Thomas Kovacs, MD

Funding

  • NIH-NIDDK Gastroenterology Training Grant (T32): No cost extension for 1 year (PI)
  • Terumo Corp: Funding for a randomized controlled trial of bleeding hemorrhoids (RCT) (Co-PI)
  • UCLA Foundation (GI Research Grants): Funding of cohort, database, pilot/feasibility, cost-effectiveness studies & RCT’s (PI)

Current research projects

  • RCT of IR embolization of hemorrhoidal arteries vs. rubber band ligation as definitive treatment for patients with severe chronic rectal bleeding from internal hemorrhoids. 
  • Single center clinical outcomes RCT of patients with iron deficiency anemia after a severe GI hemorrhage treated with high dose IV iron vs. oral iron. 
  • Correlation of artery size on histopathology of resected colon polyps with Doppler endoscopic detection of blood flow after cold or hot snare polypectomy. 
  • For patients with severe hematochezia, large over-the-scope clip (OTSC) for treatment of definitive diverticular hemorrhage and other colon lesions with stigmata of recent hemorrhage.
  • Long term clinical outcomes study of patients with chronic rectal bleeding treated with either rubber band ligation or multipolar probe thermal coagulation.
  • Incidence and risk factors for diverticulitis in patients with diverticular hemorrhage.
  • Cost analysis study of OTSC for non-variceal UGI hemorrhage based upon our RCT results.

Future research directions

  • Multicenter RCT of IV iron vs. oral iron to improve clinical outcomes of patients with iron deficiency anemia after a severe non-variceal UGI or colon hemorrhage. 
  • Teaching atlas with video cases on non-variceal UGI and colon hemorrhage – Diagnosis, Treatment, Hemostasis Techniques, and Outcomes.
  • Multivariable analysis of risk factors for delayed PPIU hemorrhage for patients on chronic anti-thrombotic drugs.
  • For patients with severe diverticular hemorrhage, a multicenter interventional RCT of urgent colonoscopy for diagnosis and definitive hemostasis compared to current US GI guidelines of CTA and elective colonoscopy.  
  • Cost analysis study of Doppler probe monitoring of arterial blood flow to prevent delayed PPIU hemorrhage in high-risk patients.

Recent key publications

Peer-reviewed papers and chapters of the Jensen GI Hemostasis Research Group

View full list of PubMed publications for Dr. Dennis Jensen

  1. Savides TS, Jensen DM. GI Bleeding (Chapter 20) In: Feldman M, Wilcox C, Brandt LJ – Editors. Sleisenger and Fordtran’s Gastrointestinal and Liver Diseases. Pathophysiology/Diagnosis/Management. Twelfth Edition. Saunders Elsevier. Philadelphia 2026
  2. Martinez M, Dakhoul L, Fatima H, Goenka MK, Gorez V, Hernandez LV, Jensen  DM, Khaykis I, Lara LF, Tadros M, Villa E, Saltzman JR. The 2025 top 10 list of endoscopy topics in medical publishing: An annual review by the American Society for Gastrointestinal Endoscopy Editorial Board. Gastrointest Endosc. 2026;103:1-16
  3. Wangrattanapranee P, Jensen DM, Jensen ME, Thibodeau G. Flat Spots are a Major Stigmata of Hemorrhage for Definitive Diverticular Hemorrhage: Evidence from Blood Flow Monitoring and Clinical Outcomes. iGIE. 2026
  4. Jensen DM, Gornbein J, Fejleh P, Lewis M & Wang H. Prediction and Prevention of Delayed Post-polypectomy-induced Ulcer Hemorrhage Based Upon an Anatomic Study and Multivariable Analyses. Digestive Diseases and Sciences. 10 February 2026
  5. Martinez M, Bartel MJ, Chua T, Dakhoul L, Fatima H, Glessing B, Jensen DM, Lara LF, Shinn B, Tadros M, Villa E, Saltzman JR. The 2024 top 10 list of endoscopy topics in medical publishing: an annual review by the American Society for Gastrointestinal Endoscopy Editorial Board. Gastrointest Endosc. 2025;102:2-13
  6. Lin ES, Dutson U & Jensen DM. Low rates of diagnosis and treatment of iron deficiency anemia after an acute severe gastrointestinal hemorrhage. Digestive Diseases and Sciences. 21 March 2025
  7. Villanueva C, Sapena V, Lo GH, Seo YS, Shah HA, Singh V, Tripathi D, Schepke M, Gheorghe C, Bonilha DQ, Jutabha R, Wang HM, Rodrigues S, Brujats A, Lee HA, Azam Z, Kumar P, Hayes PC, Sauerbruch T, Chen WC, Iacob S, Libera ED, Jensen DM, Alvarado E, Torres F, Bosch J, Baveno Cooperation-a EASL Consortium. Improving Primary Prophylaxis of Variceal Bleeding by Adapting Therapy to the Clinical Stage of Cirrhosis. A Competing Risk Meta-Analysis of Individual Participant Data. Aliment Pharmacol Ther. 2024;59:306-321
  8. Martinez M, Bartel MJ, Chua T, Dakhoul L, Fatima H, Jensen DM, Lara LF, Tadros M, Villa E, Yang D, Saltzman JR. The 2023 top 10 list of endoscopy topics in medical publishing: an annual review by the American Society for Gastrointestinal Endoscopy Editorial Board. Gastrointest Endosc 2024;100: 537-48
  9. Kovacs TOG, Jensen DM. Gastrointestinal Hemorrhage. In: Goldman L. Cooney KA. Goldman-Cecil Medicine, 27th Edition Elsevier Saunders. Philadelphia 2024. Chapter 121:882-886
  10. Jensen DM. Endoscopic Diagnosis and Treatment of Colonic Diverticular Bleeding. Gastrointest Endosc Clinics North Am. 2024;34:345-361
  11. Jensen DM. The Importance of Arterial Blood Flow Detection for Risk Stratification and Eradication to Achieve Definitive Hemostasis of Severe Non-Variceal UGI Hemorrhage. J. Clin. Med. 2023, 12(20), 6473
  12. Jensen DM. Training in GI Hemostasis. In: Cohen J. Editor. Successful Training in Gastrointestinal Endoscopy 2nd Edition. Wiley Blackwell. Hoboken, NJ. 2022; pp 195-214
  13. Wongpongsale T, Khrucharoen U, Jensen DM, Jutabha R, Jensen ME, Thibodeau G. Outcomes of Patients with Ischemic Colitis Causing Severe Colonic Hemorrhage Managed Medically or Surgically. Langenbeck’s Archives of Surgery 2022. Published online 21 February 2022. Doi.org/10.1007/S00423-022-02441-8
  14. Wangrattanapranee P, Khrucharoen U, Jensen DM, Wongpongsalee T, Jensen ME. Severe Upper Gastrointestinal Hemorrhage Caused by Reflux Esophagitis. Dig Dis Sci. 2022; 67:159-169
  15. Jensen DM, Kovacs TOG, Ghassemi KA, Kaneshiro M, Gornbein J. Randomized Controlled Trial of Over-the-Scope Clip as Initial Treatment of Severe Non-Variceal Upper Gastrointestinal Bleeding. Clin Gastroenterol Hepatol. 2021;19:2315-2323
  16. Jensen DM, Barkun A, Cave D, Gralnek IM, Jutabha R, Laine L, Lau JYW, Saltzman JR, Soetikno R, Sung JJY. Acute Gastrointestinal Bleeding: Proposed Study Outcomes and New Randomized Controlled Trials. Alim Pharm Ther. 2021; 54:616-626
  17. Nulsen B, Jensen DM, Kovacs TOG, Ghassemi KA, Dulai G, Jutabha R. Outcomes in Severe UGI hemorrhage from Dieulafoy’s Lesion with Monitoring of Arterial Blood Flow. Dig Dis Sci. 2020; Online – doi.org/10.1007/s10620-020-06679-4

Current GI research and clinical fellows

  • Josh Jones, MD: UCLA, second-year medical resident
  • Peerapol (Ice) Wangrattanapranee, MD: UC Riverside, third-year GI fellow
  • Dylan Yu, MD: UCLA, recently graduated medical student in a gap year

Past GI research fellows

  • Marine Camus, MD
  • Disaya Chavalitdhamrong, MD
  • Daniel Eshtiaghpour, MD
  • M. Philip Fejleh, MD
  • Marie-Anne Guillaumot, MD
  • Vandana Khungar, MD, MSc
  • Elissa (Ellie) Lin, MD
  • Shane Manatsathit, MD
  • Neil Marya, MD
  • Benjamin Nulsen, MD
  • Alireza Sedarat, MD
  • Thongsak Wongpongsalee, MD

Awards

  • Lifetime Achievement Award (2025) - Presented by the Southern California Society for Gastroenterology
  • Rudolph V. Schindler Award (2012) - Dr. Dennis Jensen was the recipient of the American Society of Gastrointestinal Endoscopy (ASGE) Rudolph V. Schindler Award. This Schindler Award is the society's highest honor, recognizing the person whose accomplishments in endoscopic research, teaching or service to the society exemplifies the standards of Dr. Schindler.

About Dr. Jensen

Dr. Jensen earned his medical degree at the University of Washington Medical School in Seattle. He completed a medical internship and first-year medical residency at University of Oregon and Affiliated Hospitals. He then served as a Major in the US Army Medical Corps and was director of a Preventive Medicine Department. Following the Army, he completed a second-year medical residency at Wadsworth Veterans Administration (VA) Hospital in Los Angeles and a fellowship in gastroenterology through a joint program of UCLA and Wadsworth VA Hospitals. He has been on the faculty at these institutions since completion of his GI fellowship training at UCLA.

Dr. Jensen is a professor of medicine (in-residence academic series) and a distinguished research professor of medicine, Department of Medicine at the David Geffen School of Medicine at the University of California, Los Angeles (UCLA). He also served as associate director of the UCLA/CURE: DDRCC where he directed the Human Studies Core. He was a key investigator and on the executive committee of CURE. Currently, he is a staff physician in the UCLA Vatche and Tamar Manoukian Division of Digestive Diseases and a staff physician in the GI Section of the VA Greater Los Angeles Healthcare Center. He is a member of the UCLA DDD Research Council. He directs the VA-CURE Hemostasis Research Group which performs clinical-outcomes research, teaching, and research mentoring at UCLA and West LA VA Hospitals. 

Dr. Jensen’s research interests include multi-center, prospective and randomized controlled trials (RCT’s) of diagnosis and endoscopic hemostasis of gastrointestinal (GI) hemorrhage; primary and secondary prevention of GI bleeding; GI outcomes and health service studies; and technology assessment research related to endoscopy and GI bleeding. He is also studying diagnosis and treatment of patients with iron deficiency anemia after a severe GI hemorrhage. He has been the PI or a co-investigator on many multicenter controlled trials including both national and international studies. He has been continuously funded by investigator-initiated, peer reviewed federal grants since he first joined the UCLA faculty.  These include multiple RO1 studies jointly funded by the National Institutes of Health (NIH) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Also, he has received research funding from the VA Research Service, Department of Defense (DOD), American Society for Gastrointestinal Endoscopy (ASGE), American College of Gastroenterology (ACG), UCLA Academic Senate, and industry. He has been a member of different study sections (including the VA Merit Review Board and the NIH Reviewers Reserve for special study sections), a reviewer of NIH K23 and K24 career development awards and a member of site visits to centers proposing research in gastrointestinal endoscopy, randomized controlled trials, GI technology, and GI clinical and outcomes research studies.

Dr. Jensen has three sources of funding for his research. One source is a Veterans Administration (VA) Research Service Merit Review clinical grant. His current study is a RCT of Doppler endoscopic probe for blood flow monitoring, risk stratification, and focal treatment of arterial blood flow to prevent delayed post-polypectomy induced bleeding in high-risk patients. This is a multicenter RCT now involving VA West Los Angeles, Ronald Reagan UCLA Medical Center and previously at a Los Angeles Kaiser Permanente Hospital. This is in the final stages of data analysis and reporting since enrollment and patient follow-ups have been completed. The second source of research funding is from the UCLA Foundation. This is for studies of iron deficiency anemia in patients after a severe GI hemorrhage. Included are both database studies and an RCT interventional study of high dose intravenous iron compared to oral iron for restoration of iron stores and improvement in patients’ clinical outcomes, symptoms and functional status. The third funding source for Dr. Jensen is co-PI of an RCT comparing clinical outcomes of patients with chronic, severe rectal bleeding from internal hemorrhoids treated with either rubber band ligation or superior hemorrhoidal artery embolization.  He recently completed research funding as the PI of an NIH T32 GI training grant which he directed for the last 26 years.  

Dr. Jensen has published more than 310 peer reviewed papers, case reports, chapters, books, editorials, reviews and other reports. He also has published 338 abstracts. He has been on several editorial boards and is a regular reviewer for such peer-reviewed journals as the New England Journal of Medicine, Annals of Internal Medicine, JAMA, Gastroenterology, American Journal of Gastroenterology, Gastrointestinal Endoscopy, Endoscopy, Digestive Diseases and Sciences, and the Medical Letter. He has been an invited faculty member of numerous post-graduate GI courses and NIH consensus conferences on GI hemorrhage, endoscopy research, and GI guidelines for GI bleeding, including local, regional, national, and international symposia. 

Dr. Jensen has successfully mentored many young clinical, outcomes, and endoscopy investigators for research and career development over the last 40 years. Many of his trainees are full-time faculty or clinical faculty at academic medical centers in the US or abroad. He has completed this mentored research training as the PI and director of the UCLA NIH T32 GI training grant for the last 26 years and previously through an NIH K24 Mid-career grant for mentoring and clinical research. He has received both local and national awards as a distinguished lecturer and distinguished mentor, educator, and clinical researcher. Dr. Jensen has served on numerous committees of the ASGE and is a past councilor on the ASGE Governing Board. He also served as a member of the ACG Research Committee. He recently completed service as a member of the editorial board for Gastrointestinal Endoscopy, the main journal for the ASGE. In May 2012, Dr. Jensen was awarded the Rudolf V. Schindler award, the highest award of the ASGE. In June 2025, he received a Lifetime Achievement Award from the Southern California Society of Gastroenterology. Dr. Jensen continues to have both local and international research trainees for mentoring who are investigating and publishing abstracts, manuscripts, book chapters, teaching atlases, reviews, and practice guidelines about GI bleeding (including risk stratification, diagnosis, treatments, outcomes, and prevention), clinical outcomes studies of GI diseases and endoscopy, and RCT’s with cost analyses of new GI endoscopic technologies. He also has a large number of research collaborators both in the US and internationally who are active in ongoing GI investigations and consensus conferences as well as creating new teaching atlases, videos, and GI guidelines for GI endoscopy, GI mentoring, or GI hemorrhage.

Contact us

For more information, contact Dr. Jensen by email or by calling 310-268-3569.