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Reply to Romero-Castro et al.
We read with great interest the letter by Romero-Castro et al. Our recent randomized trial demonstrated that endoscopic ultrasound (EUS)-guided combined coiling and cyanoacrylate injection (CYA) is superior to coiling alone for the management of gastric varices . We estimated a one-sided sample size of 30 participants for each group based on the obliteration rate of 82 % for coiling alone and 53 % for CYA injection that was previously described in a two-arm study .
Bhat et al. retrospectively analyzed a one-arm cohort treated with EUS-guided combined therapy, reporting a 93 % obliteration rate . If we consider the sample size proposed by Romero-Castro et al., our study should include at least 34 participants in each group for a 75 % statistical power. However, we did not consider this appropriate as the obliteration rate for EUS-guided combined therapy would be driven from a single-arm study, and combining two independent proportions from two different studies with different methodologies may be controversial, for example with the inclusion of patients with noncirrhotic variceal bleeding or patients treated with two different types, sizes, and diameters of coils (mean 5.8 coils) .
Regarding the number of coils, there are several factors, such as the gastric variceal diameter, and the type, length, and diameter of the coil itself, that can influence the number of coils required to achieve obliteration. Our study findings should be interpreted based on the data rather than the “possibilities,” as patients within our EUS-guided coiling cohort were treated with a significantly higher median number of coils (P = 0.006). Additionally, we reported a nonsignificant difference in obliteration rates between the therapies (100 % vs. 90 %; P = 0.12), contradicting the assertion of “undertreatment.” Nevertheless, we agree with Romero-Castro et al. that sample size estimation in a boarded context is challenging, with larger multicenter trials awaiting on the horizon before the most effective technique can be defined.
17 December 2020 (online)
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- 1 Robles-Medranda C, Oleas R, Valero M. et al. Endoscopic ultrasonography-guided deployment of embolization coils and cyanoacrylate injection in gastric varices versus coiling alone: a randomized trial. Endoscopy 2020; 52: 268-275
- 2 Romero-Castro R, Ellrichmann M, Ortiz-Moyano C. et al. EUS-guided coil versus cyanoacrylate therapy for the treatment of gastric varices: a multicenter study (with videos). Gastrointest Endosc 2013; 78: 711-721
- 3 Bhat YM, Weilert F, Fredrick RT. et al. EUS-guided treatment of gastric fundal varices with combined injection of coils and cyanoacrylate glue: a large U.S. experience over 6 years (with video). Gastrointest Endosc 2016; 83: 1164-1172