The aim of this study was to characterize the main vascular lesions seen in the saline controls in continuous infusion studies in monkeys. Data were collected from 17 studies over an 8-year period (ie, around 50 males and 50 females). The study was restricted to lesions at the injection site, in lungs and at the entry point. It showed that the level of the most severe procedure-related lesions (ie, necrosis with abscess formation at the injection site and at the entry point, thromboemboli and probable infarcts in lungs) was low (<10%). Minor changes such as endothelial hyperplasia and intimal thickening at the injection site, and low-graded interstitial pneumonitis in lungs were the most frequent changes (40 to 50% of the animals). Thrombi at the injection site were present in around 30% in males and 40% in females. The slightly higher incidence of thrombi in females was not explained by a difference of vessel size or by hematological differences. This study permitted an opportunity to harmonise terminology among pathologists and to define the main procedure-related changes and their incidence, which could help pathologists better interpret changes in future infusion studies.

The aim of this study was to characterize the main vascular lesions seen in the saline controls in continuous infusion studies in monkeys. Data were collected from 17 studies over an 8-year period (ie, around 50 males and 50 females). The study was restricted to lesions at the injection site, in lungs and at the entry point. It showed that the level of the most severe procedure-related lesions (ie, necrosis with abscess formation at the injection site and at the entry point, thromboemboli and probable infarcts in lungs) was low (<10%). Minor changes such as endothelial hyperplasia and intimal thickening at the injection site, and low-graded interstitial pneumonitis in lungs were the most frequent changes (40 to 50% of the animals). Thrombi at the injection site were present in around 30% in males and 40% in females. The slightly higher incidence of thrombi in females was not explained by a difference of vessel size or by hematological differences. This study permitted an opportunity to harmonise terminology among pathologists and to define the main procedure-related changes and their incidence, which could help pathologists better interpret changes in future infusion studies.

This review was performed to assess the nature and incidence of procedure-related background changes in control dogs receiving saline by continuous infusion, and to compare them with data from a similar review previously done in Cynomolgus monkeys. Data were collected from 14 dog studies performed over an 8-year period (i.e., 86 animals in total). The review was restricted to lesions at the injection site, in the lungs and at the catheter's entry point. The most frequently seen changes were endothelial hyperplasia (67.4%) and intimal thickening at the injection site (80.2%) and interstitial pneumonitis in the lungs (52.6%), all seen at a higher incidence in dogs than in primates. Although incidences of thrombosis at the injection site were similar in both dogs (27.9%) and monkeys (34.1%), the incidences of thromboemboli and secondary infarction in the lungs were much higher in dogs. This suggests that dogs have a greater propensity to thrombus formation and fragmentation at the injection site. However the fact that the femoral vein is used in monkeys and the jugular vein in dogs may explain this difference. The larger diameter of the jugular vein in the dog with its greater turbulence of blood flow possibly predisposes to fragmentation and dispersal of thrombi.