Prophylactic Pedicle Clipping Before Hot Snare Polypectomy Is Associated With Lower Immediate Bleeding Risk in Pedunculated Colorectal Polyps: A Propensity Score–Matched Retrospective Cohort Study

Inside the human colon, a network of tiny blood vessels runs just beneath the surface, supplying life to the tissue. Occasionally, a growth called a polyp forms on a stalk, drawing its nourishment from these vessels. While many polyps are harmless, doctors often remove them to prevent future problems. The standard way to remove a polyp that sits on a stalk is to use a wire loop, heated by electricity, to slice it off. This method is quick and effective, but it carries a specific risk: as the wire cuts through the stalk, it severs the blood vessels, which can cause immediate bleeding. This bleeding can obscure the doctor's view, prolong the procedure, and sometimes require emergency measures to stop the flow. For decades, the medical focus has been on how to best seal the wound after the polyp is gone, using small metal clips to close the hole and prevent bleeding that might start hours or days later. However, a different question has remained unanswered: does it help to clamp the blood supply before the cut is even made?

A team of researchers at Peking University Shenzhen Hospital set out to investigate this specific timing issue. They looked back at records from hundreds of patients who had pedunculated polyps—those with a distinct stalk—removed using the heated wire loop technique. In the standard approach used for most of these patients, the doctor would cut the polyp off first and then place clips on the remaining wound to seal it. In a smaller group of patients, the doctors took an extra step: they placed a metal clip across the base of the stalk to pinch off the blood flow before they ever touched the wire loop. Only after the blood supply was cut off did they proceed to slice the polyp away, and then they still placed the standard clips on the wound afterward. The researchers wanted to know if this "two-step" protection, which addresses the bleeding risk at the moment of the cut, offered any real advantage over the standard single-step approach, especially in a setting where closing the wound afterward was already routine.

To ensure a fair comparison, the researchers used a sophisticated matching method to pair patients from the two groups based on nearly twenty different factors, such as age, weight, medical history, and the size and location of the polyps. This allowed them to isolate the effect of the pre-cut clipping technique. The results showed a clear difference in what happened during the procedure itself. In the group where the doctors cut the polyp first, immediate bleeding occurred in nearly fifteen percent of the cases. In the group where the doctors clamped the stalk first, immediate bleeding happened in only about three percent of the cases. This reduction was consistent even when the researchers adjusted their analysis to account for the small number of bleeding events and the fact that some patients had multiple polyps removed. The data suggests that stopping the blood flow before the cut is made significantly lowers the chance of the field becoming obscured by fresh blood during the operation.

Interestingly, the study found that this pre-cut clamping did not change the rates of bleeding that occurred days later, nor did it affect other complications. This aligns with the idea that the two techniques solve different problems at different times. The clip placed before the cut handles the immediate rush of blood from the severed vessel, while the clips placed after the cut protect the healing tissue from slower, delayed bleeding. The researchers also examined whether the size of the polyp mattered. They found that the benefit of the pre-cut clamping was most noticeable for polyps with heads between ten and twenty millimeters in size. For these medium-sized growths, the technique reduced the risk of immediate bleeding by roughly eleven percentage points, meaning that for every nine patients treated this way, one bleeding event was prevented. For very small polyps, the risk was already low, and for very large ones, the technique still helped but the numbers were smaller.

The study also looked at the practical side of adding this extra step. Placing the clip before the cut did take a little more time for smaller and medium-sized polyps; for polyps under 10 mm, the median procedure time was 40 minutes compared to 30 minutes, and for those between 10 and 20 mm, it was 50 minutes compared to 35 minutes. However, it did not extend the time patients spent in the hospital, and for the largest polyps (over 20 mm), the total time was similar between the two groups. In fact, for the largest polyps, the group that used the pre-cut clip actually needed fewer total clips to finish the job, suggesting that the initial clamp might have reduced the need for extra emergency clips later. The researchers noted that the size of the polyp head was the strongest predictor of bleeding risk, accounting for more than half of the factors that influenced whether bleeding would occur.

While the findings are promising, the authors are careful to note that this was a single-center study looking back at past records, not a new experiment where patients were randomly assigned to groups. The decision to use the pre-cut clip was made by the doctors based on their judgment of each case, which could have influenced the results. Furthermore, the study did not systematically measure the thickness of the polyp stalks, a detail that likely plays a major role in bleeding risk. Despite these limitations, the data provides a strong signal that a staged approach to stopping bleeding—controlling the flow before the cut and sealing the wound after—works better than sealing the wound alone. The researchers suggest that for polyps in the ten to twenty-millimeter range, this extra precaution could become a standard part of the procedure, but they emphasize that a larger, prospective study is needed to confirm these results and to determine exactly which patients will benefit the most. Until then, the study offers a clear, practical insight: sometimes, stopping the blood before the cut is made is the most effective way to keep the view clear and the procedure safe.