Treatment Of Thrombotic Occlusion Research Articles

Treatment of subacute and chronic thrombotic occlusions of lower extremity peripheral arteries with the excimer laser: a feasibility study

Thrombus is highly prevalent in patients with recent symptoms (< 6 months) of claudication or limb ischemia due to an occluded culprit lower extremity vessels. Treatment of these thrombotic occlusions is challenging. In this feasibility study, the excimer laser (Spectranetics, Colorado Springs, CO) has been tested for its safety and ability to ablate thrombus in patients with recent arterial occlusions. Angiographic operator assessment and volumetric core lab quantitation of the thrombus were performed at baseline and after excimer laser but prior to definitive treatment of the vessel to evaluate thrombus resolution. Consecutive patients were prospectively enrolled at a single site. Procedural success was defined as achieving a residual stenosis of <30% after final treatment with no intraprocedural complications requiring additional treatment. 20 consecutive patients were enrolled in this study (8 males, mean age 69.5±11.1 years). Based on patients symptom onset, 12 patients were subacute (> 24 h, < 30 days), and 8 chronic (between 1 to 6 months). 15/20 (75%) had restenotic occlusions. Due to the long, occlusive nature of these lesions, only 8 patients had complete intravascular ultrasound images at each time point which allowed volumetric analysis by the core lab. There was no statistical difference in plaque/thrombus volume between baseline (pretreatment) and excimer laser (P=.68). There was however a significant reduction in residual angiographic stenosis post laser alone (100% vs. 66.75%±23.9%, P=.001). Procedural success was 100%. There were no deaths or amputations. Bail out stenting was performed in 10/20 (50%) patients. Embolic filters were used in 15/20 (75%) of patients. Macrodebris>2 mm were seen in 85.7% of filters. There was no in-hospital or 30-day reocclusion of the treated vessel but one patient had a vascular access complication (small AV fistula) conservatively managed. No other serious adverse events were noted. Using the excimer laser appears safe in this small feasibility study of subacute and chronic thrombotic occlusions. Angiographically, there was a significant reduction in percent stenosis with the laser alone. The limited IVUS data did not show a reduction in plaque/thrombus volume but the number of interpretable ultrasounds was small. Further data are needed to address the effectiveness of the laser in treating these thrombotic occlusions and its advantages over balloon angioplasty.

Recanalisation of thrombotic arterial occlusions with rotational thrombectomy

This study sought to assess the effectiveness of rotational thrombectomy (RT) with the Rotarex device in the treatment of thrombotic occlusions in native arteries, by-pass grafts, stents and stent-grafts. Over the last 4 years, 22 patients (14 men and 8 women; mean age 62.6 years) affected by 5 acute (<14 days) thrombotic occlusions of the native arteries (4 plaque thromboses in the common iliac artery and one on a dissection intimal flap of the external iliac artery), 17 subacute and chronic thromboses affecting 4 femoro-popliteal by-pass grafts, 10 stents (7 in the common iliac artery and 3 in the superficial femoral artery) and 3 stents-grafts were studied. Acute thromboses of native arteries were follow-up with colour-Doppler ultrasound (US) examination at 1 and 3 months. Subacute and chronic thrombotic occlusions were follow-up with colour-Doppler US examination at 1, 3, 6 and 12 months and yearly thereafter. Immediate technical success was achieved without any need for additional procedures in all acute occlusions of native arteries (4/22 cases). In the subacute and chronic occlusions, the procedure was completed with percutaneous transluminal angioplasty (PTA) (8/22), cutting balloon (6/22) and stenting (5/22). The complication rate was 4.8% (1 rupture of the external iliac artery repaired with a stent-graft). Arterial recanalisation with RT is the treatment of choice for acute thrombosis of healthy native arteries (4-7 mm); the treatment of thrombosis complicating calcified plaques or dissection intimal flaps may cause rupture of the arterial wall. In subacute and chronic occlusions of by-pass grafts, stents and stent grafts, additional procedures are necessary to achieve complete recanalisation.

Central venous access device occlusions: part 2: nonthrombotic causes and treatment.

Home care nurses commonly care for patients with central venous access devices (CVAD) for administration of a variety of infusion therapies. Catheter occlusion is a potential complication. In the February 2002 issue of the etiology and treatment of thrombotic occlusions were described. This month, the focus is on nonthrombotic causes of CVAD occlusion.

Thrombo-atherectomy: hope for pesky thrombus-containing lesions?

Angiographic lesion morphology remains an important predictor of acute and long-term clinical outcomes after percutaneous coronary interventional (PCI) procedures even in the current era of the stent. Chronic total occlusions and thrombus-containing lesions present perhaps the greatest risk for failed PCI due to technical issues or procedural-related clinical events such as noflow or distal embolization [1]. These lesion subsets may indeed benefit form a novel mechanical solution to address the technical limitations of existing devices applied to the treatment of these pesky lesion subsets. Thrombus-containing lesions represent a subset of lesions with a high risk for procedural-related thrombotic or flow-mediated complications. Thrombolytic and anticoagulant therapies have generally proven unreliable in preventing procedural-related thrombotic events and improving clinical outcomes. Antiplatelet therapies with GP IIb/IIIa inhibitors (abciximab, eptifibatide, tirofiban) have been shown to improve clinical outcome with PCI in patients with acute coronary syndromes by reducing procedural-related myocardial infarctions. Only anecdotal evidence supports the use of GP IIb/IIIa inhibitors for PCI of thrombus-containing lesions [1]. Several mechanical solutions have been proposed for intracoronary thrombectomy. The transluminal extraction catheter (TEC) was the first device developed for the purpose of cutting and aspirating thrombus [2]. The physical properties (profile and flexibility) of the TEC catheter, however, substantially limited clinical adoption of the device and caused a high frequency of dissections as well as distal embolic events. The incompatibility of the TEC catheter with contemporary-sized (6–8 Fr) guide catheters and guidewires also impacted negatively on the clinical integration of this device. The POSSIS Angiojet rheolytic thrombectomy system has been developed for peripheral vascular and selected coronary arterial lesion subsets [3]. The POSSIS catheter utilizes a unique high-pressure fluid jet and aspiration system to remove thrombus. The device is well proven for the treatment of thrombotic occlusion of peripheral vascular grafts and native vessels. The device, however, has limited application for intracoronary thrombus due to profile and a high probability for bradyarrhythmias as well as adverse hemodynamic consequences. The X-Sizer (EndiCor Medical, San Clemente, CA), as described by Kwok et al. [4], is an 8 Fr–compatible excisional thrombo-atherectomy catheter with 2.0 and 2.3 mm tip sizes. The X-Sizer removes thrombo-embolic debris by cutting with a rotating helical cutter (2,100 rpm) while aspirating the material away from the lesion through the central catheter lumen into a vacuum bottle. This excisional atherectomy device, unlike the TEC, is compatible with off-the-shelf 0.014 guidewires. Kwok et al. [4] report a retrospective angiographic analysis of the initial clinical application of the X-Sizer for the treatment of 14 complex noncalcified and thrombus-containing lesions as part of an 85-patient international multicenter phase I clinical trial [5]. Patients treated with GP IIb/IIIa inhibitors were excluded from this retrospective study. The report of Kwok et al. [4], unfortunately, reminds one of past experiences with similarly designed thrombo-atherectomy devices. The acute gain after thrombo-atherectomy with the X-Sizer was approximately 1 mm, which equates to 50% or less of the cutter dimensions (2.0 or 2.3 mm). The cut-and-suck approach effectively removed the entire thrombus in four of nine patients (40%), while three patients (33%) had persistent thrombus after the X-Sizer and adjunctive therapy with PTCA or stenting. Distal embolization occurred in only one of 14 patients; unfortunately, periprocedural CPK data and the incidence of myocardial infarction were not reported in this angiographic study. Kwok et al. [4] identify yet another potential mechanical approach for dealing with complex or thrombus-containing lesions. These feasibility data must be supported by clinical efficacy documented in the randomized multicenter trial comparing the X-Sizer with PTCA while employing contemporary mechanical (stents, embolic protection) and pharmacological therapies (GP IIb/IIIa inhibitors). An approach harmonizing mechanical and pharmacological therapies will likely prove more efficacious than simply aspirating thrombus. Catheterization and Cardiovascular Interventions 55:140–141 (2002)