Endoscopic ultrasonography was sensitive and specific in detecting choledocholithiasis
ACP J Club. 1996 May-June;124:76. doi:10.7326/ACPJC-1996-124-3-076
Prat F, Amouyal G, Amouyal P, et al. Prospective controlled study of endoscopic ultrasonography and endoscopic retrograde cholangiography in patients with suspected common-bileduct lithiasis. Lancet. 1996 Jan 13;347:75-9. [PubMed ID: 8538344]
To assess the accuracy of endoscopic ultrasonography (EUS) and endoscopic retrograde cholangiography (ERC) in patients with suspected common bile duct lithiasis.
Blinded comparison of EUS and ERC with endoscopic sphincterotomy.
Endoscopy unit of a hospital in France.
121 patients (mean age 70, 57% women) who had suspected choledocholithiasis and were likely to require endoscopic treatment. Patients who were < 50 years old and had not had cholecystectomy were excluded.
Description of Tests and Diagnostic Standard
EUS was done (GIF-EUM20 endoscope, Olympus, Japan, 7.5 and 12.0 MHz working frequencies); then ERC was done (TJF 100 videoduodenoscope, Olympus) immediately after. The observations from both procedures were recorded on a standard form by an assistant. The diagnostic standard was endoscopic sphincterotomy and instrumental exploration of the common bile duct. The EUS and ERC operators were unaware of each others' findings.
Main Outcome Measures
Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratios of EUS and ERC. An analysis of some cost implications of EUS was also done.
Endoscopic sphincterotomy detected stones in 78 patients (66%). Test characteristics for EUS and ERC are displayed in Table. The results of EUS and ERC showed agreement for the presence or absence of stones in 113 patients (95%) (95% CI 89% to 98%) and showed disagreement for 6 patients. Management with EUS done first, with ERC and sphincterotomy done only if choledocholithiasis was confirmed by EUS, was compared with 2 other management options where ERC was done first. EUS done as the initial test was associated with higher costs than were the other 2 options (12% to 20%) but with lower morbidity and fewer untreated stones.
Endoscopic ultrasonography was approximately as sensitive and specific as endoscopic retrograde cholangiography for the detection of common bile duct stones and could prevent unnecessary invasive interventions.
Source of funding: Assistance Publique-Hôpitaux de Paris.
For article reprint: Dr. F. Prat, Service des Maladies du Foie et de l'Appareil Digestif, Hôpital Bicêtre, 94275 Le Kremlin-Bicêtre, France. FAX 33-1-4521-2042.
Table. Diagnostic test characteristics for detecting common bile duct lithiasis*
|Endoscopic retrograde cholangiography||89%||100%||Infinity||0.11|
*LRs defined in Glossary and calculated from data in article.
A sensitive and noninvasive method of detecting gallstones in the common duct would be very useful. Percutaneous ultrasonography, which is noninvasive, is helpful if positive, but a negative test result cannot rule out a bile duct stone because the test has limited sensitivity. ERC is invasive and is associated with morbidity such as pancreatitis and cholangitis in 3% to 5% of patients (1). Sphincterotomy is associated with morbidity in 8% to 10% of patients (2). The procedure-related mortality may be as high as 1% (3, 4).
In Prat and colleagues' evaluation of EUS—an endoscopic procedure that is less invasive and associated with less morbidity than is ERC—the sensitivity was similar to ERC. The strength of this study is that both procedures were done independently in the same patients. A few patients with common duct stones were missed by both tests so that 4 of the 5 false-negative results with EUS were also negative with ERC; stones were found only when sphincterotomy was done because a high clinical index of suspicion existed. Thus, no available test, even ERC, is perfectly sensitive for common duct stones. The authors conclude that EUS was as sensitive and specific as ERC for the detection of common duct stones and that the use of EUS could avert the need for some invasive diagnostic ERCs.
In selected patients who have suspected common duct stones, a cost analysis suggests that an EUS-first management option has a slightly higher cost but is associated with less morbidity. It would be interesting to consider, perhaps with decision-analysis modeling, what the expected rates of various complications might be for different strategies.
EUS is likely to become a valuable diagnostic tool for deciding who among selected patients needs invasive ERC.
David F. Ransohoff, MD
University of North CarolinaChapel Hill, North Carolina, USA
Several newer studies (5, 6) have supported the finding that EUS and ERC have similar sensitivity for detecing gallstones in the common duct. Using a costing model based in the United States, the EUS-based strategy was less expensive for patients with moderate-, intermediate-, and low-risk choledocholithiasis (5).