Autologous Blood Provides the Best Cushioning Effect for Polypectomy: A Prospective Randomized Controlled Human Trial

Abstract

Background: The creation of submucosal cushion prior to polypectomy is widely used to facilitate lesion removal and to prevent the complications. The ideal cushioning agent should be inexpensive, readily available, easy to inject and create a long lasting cushion. Autologous blood was easy to inject and provided a long-lasting effect in a porcine model, but has not been previously compared to other cushioning agents in humans. Objective: To compare the cushioning properties of autologous blood, normal saline and hydroxypropyl methylcellulose (HPMC) in a prospective, randomized human polypectomy trial. Methods: Based on our previous pilot animal study a sample size (15 patients) was calculated. Patients with colorectal polyps measuring equal or greater than 1cm were enrolled and randomized into 3 cushioning agent groups: normal saline, HPMC and autologous blood. The ease of injection, duration of cushioning effect, visualization, rate of complication and ability to complete the polypectomy were recorded for each patient and then compared using student's t-test and Mann Whitney test for nonparametric values. Results: A total of 18 patients were enrolled into the study. Patients' demographic characteristics were comparable between the 3 groups. The mean size of the polyps in the different groups was not statistically significant (P = 0.06). Autologous blood was effortlessly obtained from the patient's peripheral vein and its injection was as easy as injection of the normal saline (mean injection score of 4). On the other hand, injection of HPMC was very difficult (score of 2) compared to blood or saline injection (P<0.026). The duration of the cushion created by autologous blood was comparable to HPMC (P = 0.92), whereas it was significantly longer when compared to the cushion created by saline (P = 0.018), A visible cushion was present in none of the patients at the end of polypectomy in the saline group as compared to 66% in the HPMC and 100% in the autologous blood group. The visualization score for blood was comparable to saline and HPMC. There were two perforations in the HPMC group. No significant complications occurred in both the autologous blood and saline groups. Conclusion: Autologous blood is easy to inject, creates a long lasting submucosal cushion, does not obscure visualization and prevents complications during polypectomy. It is readily available, inexpensive, and can become the ideal injection solution for submucosal cushion creation during polypectomy.