Asymptomatic portomesenteric thrombosis after colorectal surgery resolved without anticoagulation

Design

Single-centre retrospective cohort with routine day-6 CT

Population

799 consecutive patients after colorectal cancer surgery, 2019-2025

Primary outcome

Incidence and natural history of asymptomatic portomesenteric venous thrombosis

Effect

33 cases (4.1%); 100% resolution within 1 year, including all 12 observed without anticoagulation

A single centre that routinely performs CT on postoperative day 6 after colorectal cancer surgery reviewed 799 consecutive patients operated on between 2019 and 2025 (World Journal of Surgery, 18 October 2026). Asymptomatic portomesenteric venous thrombosis was found in 33 (4.1%), mostly confined to peripheral intrahepatic portal branches.

Twenty-one patients were anticoagulated and 12 were observed under a risk-stratified pathway. All 33 had complete radiological resolution within a year, including every patient who was not anticoagulated. There was no thrombus extension, portal hypertension or bowel ischaemia. In exploratory analysis, age 60 or under (OR 2.45) and a day-5 white count above 10 × 10⁹/L (OR 2.39) were associated with thrombosis.

For surgeons who find a small, non-occlusive peripheral clot on a postoperative scan done for another reason, this supports a conservative, individualised approach: surveillance imaging rather than reflex anticoagulation, thrombophilia screening or delay to adjuvant chemotherapy. The authors do not recommend routine postoperative CT to look for these clots.

• For an incidental, non-occlusive clot in peripheral intrahepatic portal branches after colorectal surgery, consider surveillance rather than reflex anticoagulation.
• Repeat imaging to confirm resolution if you choose surveillance.
• Anticoagulate main portal or superior mesenteric vein thrombosis, or any symptomatic clot, as usual.
• Avoid delaying adjuvant chemotherapy for a small peripheral asymptomatic clot.
• Do not add routine postoperative CT to look for these clots.

Why it matters

Incidental clots often trigger anticoagulation and delayed chemotherapy, and this series suggests the peripheral ones resolve on their own.

Don't overread it

Treatment was not randomised and only 12 patients were observed, so this cannot show anticoagulation is never needed; main-vein clots were not the focus.

The statistics, in plain English

With 33 events, the risk-factor odds ratios have wide intervals and were labelled exploratory by the authors. The striking result is the count: 33 of 33 resolved.

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