Physical characteristics of gallstones and the calibre of the cystic duct in patients with acute pancreatitis.

Forty-six gallbladders were examined for the number, weight, size and shape of their gallstones, and for the volume of flow, under conditions of constant pressure, that was transmitted by the cystic duct. Eighteen gallbladders were from patients who had previously suffered an attack of acute pancreatitis, and the other 28 were from control patients who had not had a known attack of pancreatitis. Cystic duct flow rates, which we assumed were related to cystic duct calibre, were greater in the pancreatitis group (mean = 282 ml/min) than in the controls (mean = 134 ml/min) (P less than 0.01). There were more stones in the gallbladders of the pancreatitis patients, and the mean stone weight was lower in this group (0.31 g compared with 0.74 g; P less than 0.02). Large stones were more frequently seen in the control gallbladders. Small, irregular or mulberry-shaped stones were the dominant stone type in 78 per cent of the pancreatitis group but in only 43 per cent of the controls (P less than 0.05). Thus a large-calibre cystic duct and numerous small stones with an irregular shape appeared to be more common in patients who had suffered acute pancreatitis, and may be factors in the pathogenesis of the attack.