Outcomes
The main patient outcomes that were evaluated were efficacy of therapy (measured by complete thrombus resolution following diagnostic intervention and a course of anticoagulation), and safety (measured by bleeding events following the procedure). For patients who had serial follow up images available for review, the 6-month follow up image (or closest available to 6 months after diagnosis) was the time point selected. If follow up imaging was not performed at 6 months or later, the latest follow up image prior to the 6-month point was used. Severity of bleeding was classified according to the International Society of Thrombosis and Haemostasis (ISTH) scale, with major bleeding episodes defined as fatal bleeding, bleeding with a decrease in hemoglobin of 2 g/dL in a 24-hour period, retroperitoneal bleeding, intracerebral bleeding, or bleeding that requires surgical intervention in operating rooms. Non major bleeding events include documented bleeding that did not meet criteria for a major bleeding episode (referred to as clinically relevant non-major and minor bleeding in the ISTH scale).19 As many of the interventional technologies employed are red blood cell depletive without leading to actual bleeding, post-interventional declines in hemoglobin that were noted without an identified bleeding event were not counted as bleeding adverse events.
The major outcomes were evaluated within the two thrombolysis groups; CDT and “on-table” thrombolysis. Additional secondary outcomes included thrombus progression/recurrence and PTS. At the time of evaluation, our center did not incorporate standard PTS scoring systems into our follow up records; nonetheless, standard symptoms of PTS were recorded, including extremity swelling, pain, redness, fullness, decreased range of motion, heaviness, and presence of ulcers. Review of symptoms for PTS were delayed until the acute phase of the DVT has passed, at 6 months following diagnosis.20