A prospective assessment of endoscopic ultrasound accuracy for diagnosing cambridge class ≥ 2 or ≥ 3 chronic pancreatitis

AIM:To prospectively verify the accuracy of endoscopic ultrasound (EUS) criteria for diagnosing mild and moderate chronic pancreatitis (CP) as defined by pancreatography using the Cambridge criteria (CC) for interpretation. METHODS: Patients with unexplained abdominal pain undergoing pancreatic EUS and ERCP were prospectively studied. EUS was performed by experienced operators aware of the clinical history, but blinded to ERCP results. The CC are as follows: 0="normal", 1 ="equivocal" (normal (N) main pancreatic duct (MPD) + <3 abnormal (aN) sidebranches (ASB)), 2="mild" (NMPD + ≥3aNSB), 3="moderate" (aNMPD + >3aNSB). "Positive EUS" was defined as the presence of any combination of 1 to 6 of the following criteria: hyperechoic foci (HF), hyperechoic strands, lobularity (L), irregular duct margins (ID), hyperechoic duct margins, and visible side branches (VS). "CP" was defined as a CC of ≥2 or ≥3. RESULTS: 98 patients: 18 CC"0", 9 CC "1", 21 CC"2", 32 CC"3", and 18 CC"4". No EUS-related complications occurred CAMBRIDGE CLASS ≥2 CHRONIC PANCREATITIS # EUS criteria ≥1 ≥2 ≥3 ≥4 ≥5 6 sensitivity 96 85 73 63 41 21 specificity 22 48 56 74 81 100 pos. pred. val. (PPV) 76 81 81 87 85 100 neg. pred. val. (NPV) 67 54 44 43 34 33 CAMBRIDGE CLASS ≥3 CHRONIC PANCREATITIS # EUS criteria ≥1 ≥2 ≥3 ≥4 ≥5 6 sensitivity 96 90 80 74 50 26 specificity 15 40 50 69 81 96 pos. pred. val. (PPV) 54 54 63 71 74 87 neg. pred. val. (NPV) 78 79 71 72 61 55 Univariate analysis (n=66) showed 4 independent predictors of CP: HF(p=0.006), ID(p=0.026), VS(p=0.036), and L(p=0.053). SUMMARY: Presence of 6 EUS criteria is diagnostic (PPV 100%) of mild CP(CC≥2) and highly predictive (PPV87%) of moderate CP (CC≥3); ≥4 criteria is highly predictive of mild CP(CC≥2). This is true even when powerful predictors of CP, such as calcifications, duct dilation, and pseudocysts are not used. CONCLUSION: In patients with unexplained abdominal pain, EUS is a safe and effective in diagnosing ERCP-defined mild and moderate CP.