If your vet suggested that there was a good chance of extensive hemorrhage in this case, then it is probably best that he did not proceed. A man has to know his limitations, and it is far better that he pulled out rather than to perform a risky procedure. As a general rule - in these cases, caval ligation is often of benefit. In some cases, caval blockage of only 50% may be enough to develop an adequate level of collateral circulation. However, this is a salvage operation, and is associated with about a 15% mortality. There is little way to determine whether adequate collateral circulation has occurred before the cava is ligated - it is based on an educated assessment of the situation and knowing that there are few other options. Cryosurgery is another possibility - the use of the cryoprobe is associated with less risk than a scalpel blade when used in proximity to the cava - vessels are relatively resistant to the freezing technique. However, with this procedure, there is a higher chance that the malignancy will not be completely removed, especially if it goes around and under the cava. The use of a vascular microsurgeon may be another viable way to approach the problem - these specialists are generally not available to all, necessitating the use of the other techniques. You can't fault your vet for knowing when to call in the cavalry - I know you and Florian all want the best outcome for this surgical procedure. With kindest regards, Bruce Williams, DVM [Posted in FML issue 3476]