Managing a second episode of thrombosis while on antithrombotic treatment

How should we manage a patient who has had a second episode of thrombosis while receiving adequate antithrombotic treatment?

James Douketis: This is a very challenging clinical scenario when a patient develops thrombosis despite our best efforts to prevent it or prevent it from worsening and treat it. My first question would be: why did this occur? And a couple of reasons might be: does the patient have some underlying disease, like a cancer, that would be creating a prothrombotic state to cause recurrence? Another situation that is less common but very important: does that patient have heparin-induced thrombocytopenia, which, as you know, is a very prothrombotic state.

So we need to look for, first of all, the causes of the recurrence. Are there other factors, mechanical factors – that is, for example, extrinsic compression from a tumor or other process, a musculoskeletal process that has led to the recurrence? Once we identify the cause, then we can adjust our treatment accordingly. For example, if somebody with cancer develops a second thrombosis, then what we can do is increase their dose of low-molecular-weight heparin by 25% to 30%. But this remains a challenging question. Ascertain what you think the causes are and adjust your treatment according to those causes.