Supplementary Material for: Air Cholangiography Vs Contrast Cholangiography in Patients with Hilar Biliary Obstruction: A Systematic Review and Meta-analysis

Background/Aims:
To minimize the risk of post-procedure complications, air cholangiography has been proposed as an alternative to contrast cholangiography in patients with hilar biliary obstruction undergoing endoscopic retrograde cholangiography. We compared the rate of post-ERCP complication between these two groups.
Methods:
We systematically reviewed all studies that compared the safety, success, and complication rate of air vs contrast cholangiography in malignant hilar obstruction patients.
Results:
A total of six studies consisting of 450 patients were included in the analysis. The overall rate of post-ERCP complication was less in the air cholangiography group (RR 0.43, 95% CI 0.30-0.61, I2 1.97%)) compared to the contrast cholangiography group. Compared to contrast cholangiography, the pooled risk of post-ERCP cholangitis was significantly lower in the air cholangiography group (RR 0.25, 95% CI 0.14-0.44, I2 0%). There was no difference in risk of post-ERCP pancreatitis (RR 0.79, 95% CI 0.32-1.94, I2 0%), bleeding (RR 1.17, 95% CI 0.30-4.54) and 30-day mortality (RR 0.59, 95% CI 0.23-1.50, I2 0%) between the two groups. The pooled odds of clinical (OR 1.14, 95% CI 0.39-3.34, I2 0%) and technical success (OR 2.91, 95% CI 0.52-16.35, I2 0%) were similar between both groups.
Conclusion:
In comparison to contrast cholangiography, air cholangiography had a better safety profile and less rate of post-ERCP complications.

Keywords:
Endoscopic retrograde cholangiopancreatography, Air cholangiogram, Contrast cholangiogram, Cholangitis, meta-analysis.