Daily catheter-directed single dosing of t-PA in treatment of acute deep venous thrombosis of the lower extremity

Abstract

The strong fibrin affinity of recombinant tissue plasminogen activator (rt-PA) theoretically obviates continuous infusion or replacement of t-PA after direct intrathrombic injection. This hypothesis led the authors to evaluate single daily catheter-directed injection of rt-PA as a thrombolytic treatment for acute deep vein thrombosis of the lower extremity. Once-daily injection of rt-PA was performed in large thrombosed veins (popliteal or larger) with use of pulse-spray catheters and in small thrombosed veins in patients' calves with use of 3-4-F coaxial catheters. Patients received only full systemic anticoagulation on his/her patient care unit. This dosing regimen has been tested in 10 patients (12 legs) with a maximum dose of 50 mg per leg per day. Extensive thrombolysis was achieved in nine patients and partial thrombolysis was achieved in one patient, at an average total dose of 106 mg of rt-PA per leg. Minor bleeding was seen in three patients and no transfusions were needed. Our technique and the rationale for this pilot study is the focus of this article.

Figures

Figure 1

Bilateral lower extremity and inferior vena cava (IVC) thrombosis after IVC filter placement treated with 100 mg rt-PA per leg. (a) Pretreatment (left) venogram (injection of lower IVC) shows contrast material pooling in interstices of thrombus in the IVC and both iliac veins. Thrombosis extended into femoral, popliteal (not shown), and calf veins bilaterally. Posttreatment (right) venogram shows clearance of thrombus from left iliac and femoral veins. (b) Left popliteal veins and calf vein thrombosis (left) cleared after treatment with rt-PA (right). Note the calf veins group into anterior (a) and posterior divisions (p), which join just above the knee joint space to form the popliteal vein. Variations in the popliteal vein are common. There is contrast media in subcutaneous fat (E) from test injection during the initial catheterization venipuncture attempt, which proved to be superficial to the popliteal vein.

Figure 2

Treatment of calf vein thrombosis (retrograde catheterization). (a) Rapid pulsed injection of rt-PA through pulse-spray catheter (arrowheads) into a small thrombus-filled calf vein can cause extravasation of previously injected contrast media into muscle (striated pattern; arrows). The patient developed a small (approximately 5 mL) hematoma during therapy. (b) Gentle hand injection of contrast media (or rt-PA) through a 3-F catheter (introduced through a coaxial 4-F catheter) allows one to treat both the catheterized calf vein (1) and its companion vein (2) via small communicating veins (arrows) with a lower risk of extravasation or vein rupture.