Chronic pancreatitis is characterized by persistent and severe pain, which can be relieved by decompression of the main pancreatic duct (MPD). Both ductal and interstitial pressures have been shown to be increased in chronic pancreatitis in patients. A study was carried out of pancreatic interstitial pressure and pancreatic blood flow in normal cats and those in which chronic obstructive pancreatitis had been induced 5 weeks earlier to determine the effect of decompression of the MPD. In the normal pancreas, median(interquartile range (i.q.r.)) basal interstitial pressure was 0.05(1.2) mmHg and median(i.q.r.) basal pancreatic blood flow 58.3(24.3) ml per min per 100 g. Secretory stimulation did not change the interstitial pressure significantly, but was associated with a 40 per cent increase in median(i.q.r.) blood flow to 81.8(45.8) ml per min per 100 g. In contrast, in chronic obstructive pancreatitis, the median(i.q.r.) basal interstitial pressure was 2.0(1.5) mmHg, which was significantly higher than in the normal gland, and median(i.q.r.) pancreatic blood flow was 38.3(9.8) ml per min per 100 g, significantly lower than in the normal pancreas. Furthermore, secretory stimulation was associated with a significant increase in median(i.q.r.) interstitial pressure to 3.3(1.6) mmHg and a simultaneous decrease in median(i.q.r.) blood flow to 31.5(13.7) ml per min per 100 g. After decompression of the MPD in cats with chronic obstructive pancreatitis, the median(i.q.r.) basal interstitial pressure was 2.0(1.4) mmHg and on secretory stimulation 1.8(1.5) mmHg. Decompression thus prevented the increase in interstitial pressure seen in the animals with obstruction. In contrast, ductal decompression improved the median(i.q.r.) basal pancreatic blood flow to 45.9(38.4) ml per min per 100 g and, furthermore, this increased significantly on secretory stimulation to a median(i.q.r.) of 81.4(47.8) ml per min per 100 g. Decompression thus restored the normal pattern of secretory hyperaemia. Within the confines of this model, these observations demonstrate that chronic obstructive pancreatitis exhibits a compartment syndrome that is relieved by duct drainage.

No abstract

We investigated the etiology of interstitial hypertension in chronic pancreatitis by examining the relationship between pancreatic ductal and interstitial pressures in cats. The main pancreatic duct was cannulated in the tail of the gland and perfused at 1, 2, or 5 ml/hr, to simulate pancreatic secretion. Intraductal and interstitial pressures were measured in four groups of animals: (1) normal cats; (2) normal cats after acutely narrowing the main duct to 25% of its original diameter; (3) normal cats after encasing the body and tail in a rigid latex capsule; and (4) cats with chronic pancreatitis created by narrowing the main duct five weeks earlier. Duct perfusion increased intraductal pressure in all of the cats, but significantly more in groups 2, 3, and 4 compared to group 1. Pancreatic interstitial pressure was unchanged by duct perfusion in groups 1 and 2, but increased in groups 3 and 4. We concluded that the compliant tissue of the normal pancreas expanded to effectively dissipate the increase in duct pressure associated with duct perfusion. In chronic pancreatitis, the inelastic parenchyma and capsule limited the distensibility of the gland, which resulted in elevated interstitial pressures during duct perfusion.