Mechanical Thromboembolectomy Research Articles

The Predictive Value of Qanadli and Miller Index Scores in Patients with Intermediate-High–Risk and High-Risk Pulmonary Emboli Undergoing Aspiration Thrombectomy

PurposeTo evaluate the correlation between clot burden and pulmonary artery pressures in patients undergoing suction thromboembolectomy for high-risk and intermediate-high–risk pulmonary embolism with secondary outcomes of 30-day mortality and intensive care unit (ICU) length of stay. Materials and MethodsInstitutional review board (IRB) exemption was granted for this retrospective study. The charts of 120 consecutive patients who underwent mechanical thromboembolectomy using the Flowtriever system (Inari Medical, Irvine, California) between February 2020 and August 2022 were retrospectively reviewed, and the following data were collected: (a) preprocedural B-type natriuretic peptide and creatinine levels, (b) echocardiographic findings, (c) preprocedural and postprocedural pulmonary artery pressures, (d) ICU length of stay, and (e) 30-day mortality. Clot burden was scored using Qanadli and Miller indices and correlated with the clinical outcomes. ResultsOf the 120 patients who underwent thromboembolectomy, pulmonary artery pressures and diagnostic-quality angiograms were available in 109 patients. In the 109 patients with adequate data, Qanadli, preprocedural Miller, and postprocedural Miller scores correlated with pulmonary artery pressures. Neither was independently associated with ICU length of stay. Freedom from 30-day mortality was 91%, and embolism-specific mortality was 92%. All-risk and high-risk patients who survived demonstrated a significantly lower preprocedural and postprocedural Miller score, respectively. ConclusionsThrombus burden as measured by the Qanadli and Miller scores appeared to be correlated with pulmonary artery pressures. Furthermore, catheter-directed thromboembolectomy led to a reduction in Miller scores, which appeared to be correlated with a reduction in pulmonary pressures. In high-risk patients, a reduced postprocedural Miller score and pulmonary pressure demonstrated improved 30-day survival. Further investigation into the association between Miller scores and patient mortality is warranted to stratify patients who would benefit from emergency intervention.

Percutaneous Mechanical Thromboembolectomy in Acute and Subacute Lower Limb Ischemia: How I Do It

AbstractThis article describes the author's approach to peripheral arterial thromboembolism and describes the step-by-step access, approach, and technique depending on the site and location of occlusion.

Abstract No. 591 Purse-string technique for venous closure after large-bore mechanical thromboembolectomy

Mechanical removal of clots in patients with pulmonary embolism and deep venous thrombosis is an attractive alternative to pharmacological treatment or catheter-directed lytic infusion. The most effective mechanical thrombectomy devices have large calibers and require large size venous puncture. The size of venotomy have been a limiting factor for more widespread use of these devices. Almost all of these patients are also on anticoagulation that potentially increases the chance of bleeding and procedural complications.

FlowTriever System for mechanical thromboembolectomy.

The systemic or catheter-directed infusion of thrombolytics benefits patients with massive and probably submassive pulmonary embolism. However, the risk of bleeding may offset benefits in a substantial number of patients. Percutaneous mechanical thromboembolectomy is an alternative to thrombolysis in those patients with contraindications to the lytic therapy, also potentially a way to avoid systemic or catheter-directed infusion of the thrombolytic all together. The Inari FlowTriever System (Inari Medical Inc, CA, USA) is the first USFDA-cleared large-bore aspiration thrombectomy device with pulmonary embolism thrombectomy indication. This article is a review of the FlowTriever System, its clinical use, current supportive literatesand future research directions.

Percutaneous Mechanical Thromboembolectomy in Acute Lower Limb Ischemia.

To analyze the immediate outcome of percutaneous mechanical thromboembolectomy in acute infrainguinal leg ischemia in a consecutive cohort of patients with acute lower limb ischemia. We retrospectively analyzed the data of 156 acute infrainguinal ischemic events in 148 patients. Patients presented with acute limb ischemia Rutherford category I in 68 cases (44%), Rutherford category II A in 64 instances (41%) and Rutherford II B in 24 instances (15%). In 62 cases (39.7%), the occlusion site started below the knee joint level, in 94 (60.3%) cases above. As a basic technique, an intervention was started by manual aspiration but if aspiration failed, an additional device was added. Most frequently, a rotational thrombectomy device (Rotarex, Straub Medical, Wangs, Switzerland) was used. An antegrade access to the femoral artery was the preferred access to the limb (154/156). In 145 of 156 incidents, a technical success was achieved (93%). Aspiration was used in 153 cases (98%). Rotational thrombectomy by use of the Rotarex catheter was added in 60 cases (38%). Directional atherectomy was applied in a total of five patients. As main technical complications, a downward embolization occurred (n = 11). There were four surgical groin revisions. Five patients died during the early follow-up with four not related to the intervention. Clinically, 135 patients (86.5%) showed an improvement in their clinical situation. Acute lower limb ischemia can be successfully treated by mechanical thromboembolectomy only by combining aspiration embolectomy with rotational thrombectomy in most cases but manual aspiration alone will frequently fail especially above the knee joint level.

Cerebral Ischemic Reperfusion Injury Following Recanalization of Large Vessel Occlusions.

Although stroke has recently dropped to become the nation's fifth leading cause of mortality, it remains the top leading cause of morbidity and disability in the US. Recent advances in stroke treatment, including intravenous fibrinolysis and mechanical thromboembolectomy, allow treatment of a greater proportion of stroke patients than ever before. While intra-arterial fibrinolysis with recombinant tissue plasminogen is an effective for treatment of a broad range of acute ischemic strokes, endovascular mechanical thromboembolectomy procedures treat severe strokes due to large artery occlusions, often resistant to intravenous drug. Together, these procedures result in a greater proportion of revascularized stroke patients than ever before, up to 88% in 1 recent trial (EXTEND-IA). Subsequently, there is a growing need for neurointensivists to develop more effective strategies to manage stroke patients following successful reperfusion. Cerebral ischemic reperfusion injury (CIRI) is defined as deterioration of brain tissue suffered from ischemia that concomitantly reverses the benefits of re-establishing cerebral blood flow following mechanical or chemical therapies for acute ischemic stroke. Herein, we examine the pathophysiology of CIRI, imaging modalities, and potential neuroprotective strategies. Additionally, we sought to lay down a potential treatment approach for patients with CIRI following emergent endovascular recanalization for acute ischemic stroke.

Catheter-Directed Treatment of Pulmonary Embolism: A Systematic Review and Meta-Analysis of Modern Literature.

We summarize the evidence for the safety and efficacy of catheter-directed thrombolysis (CDT) with and without ultrasound-assisted therapy for treating submassive and massive pulmonary embolism (PE) in a systematic review. The primary efficacy outcome was mortality. Outcomes were pooled across studies with the random-effects model. Twenty-four studies enrolled 700 patients in total; 653 received mechanical thromboembolectomy treatments for PE (mortality rate, 9% [95% confidence interval (CI), 6%-13%], P = .12; rate of minor complications, 6% [95% CI, 2%-13%]). In the ultrasound-accelerated thrombolysis (USAT) studies, the mortality rate was 4% (95% CI, 1%-11%) and in the non-USAT studies, it was 9% (95% CI, 6%-13%). Secondary safety outcomes were all bleeding events, which occurred in 12% (95% CI, 7%-20%) of the USAT studies and in 10% (95% CI, 5%-20%) of the non-USAT studies. Current clinical evidence does not prove USAT is superior over CDT methods.

Novel Thrombectomy System for Below-the-Knee and Visceral Arterial Interventions: PRISM Retrospective Interim Results

Purpose Existing endovascular options in the treatment of peripheral and visceral arterial thromboembolism face the challenges of incomplete revascularization and significant bleeding risk (among other complications). The Penumbra/Indigo Systems (Alameda, California) are designed to address these challenges by providing a novel approach to mechanical thrombo-embolectomy in the periphery using a trackable, relatively small diameter aspiration system that has a proven track record in the treatment of ischemic stroke. The PRISM trial is the first multicenter study designed to obtain initial safety and effectiveness data as well as to define optimal technique for the use of these systems in patients with confirmed peripheral or visceral artery occlusions. This abstract outlines the current status of the trial and discusses its preliminary findings. Material and Methods To date, 38 patients have been enrolled in this retrospective, single-arm, multicenter trial (total planned enrollment = 100). Mechanical thrombo-embolectomy using the Penumbra/Indigo Systems was performed in cases of failed thrombolysis, acute ischemia without adequate time for thrombolysis, or in patients with emboli as a complication of an endovascular intervention. The primary site of occlusion was located in the popliteal (17/38 patients, 44.7%), peroneal (5/38, 13.2%), superficial femoral (4/38, 10.5%), posterior tibial (4/38, 10.5%), profunda femoris (2/38, 5.3%), superior mesenteric (2/38, 5.3%), anterior tibial (2/38, 5.3%), renal (1/38, 2.6%), or brachial (1/38, 2.6%) arteries. Baseline characteristics were obtained and an angiographic assessment of vessel patency was recorded using the Thrombolysis in Myocardial Infarction (TIMI) score classifications both before and after use of the device in order to assess technical effectiveness. A review of procedural complications and adverse events was conducted to monitor safety. Results Mean patient age was 71.6 (standard deviation [SD] 14.8) years and 44.4% (16/38) were female. Procedural information presented in the following analyses was available for 24 patients and final revascularization data was available for 22 patients at the time of this abstract (data collection ongoing). A baseline angiographic TIMI score of 0 or 1 was reported for all 24 patients. Prior to intervention with the Penumbra/Indigo Systems, 41.7% of patients had no prior treatment, 45.8% received thrombolytic therapy alone, 4.2% received mechanical intervention alone, and 8.3% received both. The mean time from symptom onset to procedure was 5.3 days (SD 7.4). Following mechanical thrombo-embolectomy, 86.4% of patients were successfully revascularized to TIMI 3 and 13.6% to TIMI 2 flow. Four adverse events were reported, 1 of which was classified as serious (cardiac arrest, not related to use of the study device). Three cases were noted in which distal branch occlusion occurred secondary to emboli during the procedure. None of these 3 events were clinically significant. Conclusions Early experience with the Penumbra/Indigo Systems shows promising results with safe and effective mechanical thrombo-embolectomy in the peripheral arterial vasculature. Its successful use across a broad range of clinical applications including acute ischemia, removal of emboli that occurred during other endovascular procedures, and after failed thrombolysis is encouraging. Optimal technique will be discussed.

Abstract W P26: Meta-analysis Of Studies Using Solitaire And Trevo Pro Stent Retriever Devices For Mechanical Thromboembolectomy In Acute Cerebral Ischemia

Objective: To report rates of recanalization and symptomatic intracerebral hemorrhage (SICH) after mechanical thromboembolectomy using Solitaire and Trevo Pro devices in acute cerebral ischemia using meta-analysis of published studies. Methods: We identified all studies that used Solitaire or Trevo devices for mechanical thromboembolectomy in treatment of acute cerebral ischemia using a search on PubMed and Cochrane libraries, stroke trials database, proceedings of neurology and neurosurgery related conferences, and supplemented by a review of bibliographies of selected publications. Recanalization was assessed using TICI >2a and rates of SICH were recorded. For the meta-analysis, forest plots and statistical analysis including event rates [ER] with 95% confidence intervals [CI] based on both fixed and random models were performed using Comprehensive Meta-Analysis Software. The presence of publication bias was interrogated by funnel plot of Standard Error by log odds ratio. Results: Eighteen studies with Solitaire device and five with Trevo device were identified and included in the meta-analysis. There were a total of 433/505 (85%, ER 0.85 [CI] 0.80-0.88, P<0.001) successful recanalizations with Solitaire device whereas 196/243 (80%, ER 0.80 [CI] 0.74-0.85, P<0.001) successful recanalizations were noted with Trevo device. The incidence of SICH was 45/505 (9%, ER 0.09 [CI] 0.06-0.14, P<0.001) with Solitaire device and 17/243 (6%, ER 0.06 [CI] 0.049-0129, P<0.001) with Trevo device after mechanical thrombectomy. There was no publication bias. Conclusions: Meta-analysis of studies reveals similar rates for recanalization and SICH after mechanical thromboembolectomy using Solitaire or Trevo Pro devices.

Stroke Severity May Impact Speed of Diagnosis & Thrombolysis (P04.058)

Objective: To demonstrate that clinical severity affects speed of diagnosis and treatment of acute ischemic stroke. Background Prior stroke treatment trials demonstrate that earlier thrombolysis leads to greater benefit; however, recent data suggests that less than 1/3 of stroke patients had door-to-needle times Design/Methods: Retrospectively, all acute ischemic stroke patients who received IV rt-PA alone were identified in our stroke database. Patients who received IA rt-PA or mechanical thromboembolectomy were excluded from analysis. Door-to-needle times and NIHSS scores at admission and discharge were identified. Statistical analysis was done using the Mann-Whitney test and a regression model for adjustment of admission NIHSS score severity. Results: IV rt-PA alone was given to 112 AIS patients; 8 lacked discharge NIHSS scores, so 104 were included for analysis. Fifty received IV rt-PA within 60 minutes, 54 after 60 minutes. Mean admission NIHSS scores were 11.2 and 8.8 (p=0.016) for the 60min groups, respectively. The mean improvements in NIHSS scores at discharge were 6.9 and 5.1 (p=0.606), respectively. When the same data set was dichotomized at a target of 80 minutes, the admission scores were 10.6 ( 80min, n=24) (p=0.142). The mean improvements in NIHSS scores for this time dichotomization were 6.8 and 3.0 (p=0.033), respectively. Conclusions: Our experience suggests that greater stroke severity is associated with earlier diagnosis and treatment. When stroke severity on admission is adjusted, the data shows a greater degree of improvement for patients who are treated earlier, confirming prior reports in the literature. Our data may also suggest that less severe stroke cases may present more of a diagnostic challenge, which may delay treatment; however, further review of nation-wide data is necessary to fully answer this question. Disclosure: Dr. Nair has nothing to disclose. Dr. Wang has nothing to disclose. Dr. McNeil has nothing to disclose. Dr. Wang has nothing to disclose. Dr. Jahnel has received personal compensation for activities with Genetech as a Consultant. Dr. Stapel has nothing to disclose. Dr. Stapel has nothing to disclose. Dr. Stapel has nothing to disclose. Dr. Stapel has nothing to disclose. Dr. Beck has nothing to disclose. Dr. Alanis has nothing to disclose. Dr. Talkad has received personal compensation for activities with Genentech, Inc. as a speaker. Dr. Wang has received personal compensation for activities with Sanofi-Aventis Pharmaceuticals, Inc. and Boehringer Ingelheim Pharmaceuticals, Inc.

Abciximab after IV rt-PA for Fluctuating Lacunar Syndrome (P07.005)

Objective: To assess the safety and feasibility of combining IV rt-PA with IV abciximab within a 24 hour period for treatment of worsening lacunar syndromes. Background Lacunar strokes are often preceded by warning syndromes and are a major cause of progressive motor deficit. Some controversy exists about the correct management of Fluctuating Lacunar Syndromes (FLS). We present our experience using IV abciximab within 24 hours of IV rt-PA thrombolysis for FLS. Design/Methods: We retrospectively identified all patients who received IV rt-PA followed by IV abciximab within a 24hr period. We excluded all patients who received IA rt-PA, mechanical thromboembolectomy, and a longer time period between rt-PA and abciximab. We identified the NIHSS score at four different times: at presentation, after IV rt-PA, before IV abciximab, and at discharge; we also reviewed imaging reports for any evidence of hemorrhagic conversion. Results: 18 patients received IV rt-PA followed by IV abciximab within 24 hours. All four NIHSS scores were recorded in 12 patients; the remaining 6 patients only had documentation of deterioration after IV rt-PA, without specific score mentioned. The overall mean admission score was 9, and the mean improvement post-TPA was a decrease of 4 (in the 12 patients). For those 12 patients, the mean deterioration post-TPA was an increase of 4, indicating a return to pre-thrombolytic stroke severity. After IV abciximab, the mean score at discharge (for all patients) was 3, for an overall improvement of 6, from admission to discharge. No hemorrhagic conversions were identified, either after IV rt-PA or after IV abciximab. Conclusions: No therapeutic options currently exist for lacunar stroke patients who deteriorate after thrombolysis with IV rt-PA. Our results suggest that abciximab may be beneficial and safe for this population. Larger randomized trials will need to be conducted to prove safety and efficacy. Disclosure: Dr. Nair has nothing to disclose. Dr. McNeil has nothing to disclose. Dr. Wang has nothing to disclose. Dr. Jahnel has received personal compensation for activities with Genetech as a Consultant. Dr. Stapel has nothing to disclose. Dr. Stapel has nothing to disclose. Dr. Stapel has nothing to disclose. Dr. Stapel has nothing to disclose. Dr. Hodges has nothing to disclose. Dr. Beck has nothing to disclose. Dr. Alanis has nothing to disclose. Dr. Talkad has received personal compensation for activities with Genentech, Inc. as a speaker. Dr. Wang has received personal compensation for activities with Sanofi-Aventis Pharmaceuticals, Inc. and Boehringer Ingelheim Pharmaceuticals, Inc.

Anterior Communicating Artery Aneurysm Rupture After Intravenous Thrombolysis for Acute Middle Cerebral Artery Thromboembolism

The use of intravenous recombinant tissue plasminogen activator (IV rtPA) has become an integral part of modern acute ischemic stroke management; however, its use has been associated with the development of intracranial hemorrhage in 6.4% of patients. It is possible that underlying and unsuspected vascular lesions, such as cerebral aneurysms, may lead to intracranial hemorrhage after IV rtPA thrombolysis. We present a previously unreported case of a 51-year-old woman who presented with subarachnoid hemorrhage from an acutely ruptured anterior communicating artery aneurysm after IV rtPA treatment for acute left middle cerebral artery thromboembolism. The patient underwent mechanical thromboembolectomy of the left middle cerebral artery occlusion with resultant TIMI (Thrombolysis In Myocardial Infarction) grade I recanalization, followed by coil embolization of the anterior communicating artery aneurysm. The patient never improved neurologically, and she ultimately died. Screening to identify patients at risk for development of hemorrhagic complications from underlying structural vascular lesions before the use of IV rtPA with computed tomography angiography should be considered.

Stent Placement in Acute Cerebral Artery Occlusion

Stent placement has been applied in small case series as a rescue therapy in combination with different thrombolytic agents, percutaneous balloon angioplasty (PTA), and mechanical thromboembolectomy (MT) in acute stroke treatment. These studies report a considerable mortality and a high rate of intracranial hemorrhages when balloon-mounted stents were used. This study was performed to evaluate feasibility, efficacy, and safety of intracranial artery recanalization for acute ischemic stroke using a self-expandable stent. All patients treated with an intracranial stent for acute cerebral artery occlusion were included. Treatment comprised intraarterial thrombolysis, thromboaspiration, MT, PTA, and stent placement. Recanalization result was assessed by follow-up angiography immediately after stent placement. Complications related to the procedure and outcome at 3 months were assessed. Twelve patients (median NIHSS 14, mean age 63 years) were treated with intracranial stents for acute ischemic stroke. Occlusions were located in the posterior vertebrobasilar circulation (n=6) and in the anterior circulation (n=6). Stent placement was feasible in all procedures and resulted in partial or complete recanalization (TIMI 2/3) in 92%. No vessel perforations, subarachnoid, or symptomatic intracerebral hemorrhages occurred. One dissection was found after thromboaspiration and PTA. Three patients (25%) had a good outcome (mRS 0 to 2), 3 (25%) a moderate outcome (mRS 3), and 6 (50%) a poor outcome (mRS 4 to 6). Mortality was 33.3%. Intracranial placement of a self-expandable stent for acute ischemic stroke is feasible and seems to be safe to achieve sufficient recanalization.

Single center experience with provisional abciximab therapy in complex lower limb interventions

Abciximab, a glycoprotein IIb/IIIa antagonist has been shown to improve patency and clinical outcome in patients undergoing endovascular recanalization of femoro-popliteal occlusions. However, data on abciximab therapy in complex peripheral catheter interventions of lower limbs are quite limited. The objective of this retrospective study was to evaluate the clinical and hemodynamic outcomes of patients treated with provisional abciximab during complex peripheral catheter interventions. Analysis of a consecutive series of 44 patients with provisional abciximab therapy in complex peripheral catheter interventions with imminent risk of early rethrombosis defined as revascularization of arterial occlusions associated with one or more of the following additional circumstances named as time-consuming intervention > 3 hours, compromised contrast flow not solved by stenting, distal embolization not solved by mechanical thromboembolectomy, and peri-interventional notice of thrombus evolution despite adequate heparin adjustment of lower limbs. Adjunctive abciximab therapy was started in accordance to percutaneous coronary bailout situations. The decision to add abciximab was based on the decision of the operator and went along with the judgement that there is a rising risk of reocclusion due to the progressive complexity of an individual intervention. A bolus of 0.25 mg per kilogram of body weight, followed by a maintenance infusion of 0.125 microg/kg/min (up to a maximum dosage of 10 microg/min) for 12 hours was administered. Clinical and hemodynamic outcome was prospectively assessed at discharge, three and six months after the index procedure. The occluded artery of 44 limbs was in the iliac (2%), in the femoro-popliteal (73%) or below the knee segment (25%). Overall, occlusion length was 11.5 +/- 6.5 cm. Technical success rate was 95%. Mean ABI increased from 0.5 +/- 0.16 to 0.88 +/- 0.19 (p < 0.001) with immediate hemodynamic improvement of 91%. Overall, sustained clinical improvement was 84% and 66% at three and six months follow-up, with best results in iliac (100%), followed by below the knee (73%) and by femoro-popliteal segment (63%) at six months, respectively. Overall, secondary clinical improvement was 86% at six months. Minor and major bleeding complications were 16% and 9%, respectively. Abciximab should be noticed as medical adjunct in the interventional armamentarium to prevent imminent rethrombosis in complex peripheral catheter interventions.

Mechanical Thromboembolectomy for Acute Ischemic Stroke

The purpose of the study was to compare efficacy and potential complications of 2 commercially available devices for mechanical thromboembolectomy. Devices were tested in an established animal model allowing the use of routine angiography catheters and thrombectomy devices. Radio-opaque thrombi were used for visualization of thrombus-device interaction during angiography. The Merci Retrieval System and the Catch Thromboembolectomy System were assessed each in 10 vessel occlusions. For every occluded vessel up to 5 retrieval attempts were performed. Sufficient recanalization was achieved with the Merci Retriever in 90% of occlusions, and with the Catch device recanalization was achieved in 70% of occlusions. Recanalization at the first attempt occurred significantly more often with the Merci Retriever compared to the Catch device (OR, 21; 95% CI, 1.78-248.11). Consequently, significantly more attempts (P=0.02) had to be performed with the Catch device; therefore, time to recanalization was longer. Thrombus fragmentations during retrieval were caused more often by the Catch device compared to the Merci Retriever (OR, 15.6; 95% CI, 1.73-140.84), resulting in a higher distal embolization rate. During retrieval both devices lost thrombotic material at the tip of the guide catheter, which was then aspirated in most cases. Both distal devices are effective for thromboembolectomy. To avoid loss of thrombotic material and distal embolization, the use of large luminal balloon guide catheters and aspiration during retrieval seems to be mandatory. The design of the Merci Retriever appears to be more efficient during thrombus mobilization and retrieval with less fragmentation compared to the Catch Thromboembolectomy System.

Analysis of Thrombi Retrieved from Cerebral Arteries of Patients with Acute Ischemic Stroke.

To obtain insights into the pathogenesis of ischemic stroke, we analyzed thromboemboli and other occlusive material retrieved acutely from the cerebral arteries of patients. The experimental design was an observational study in 25 consecutive patients with acute ischemic stroke treated by endovascular mechanical thromboembolectomy. Patients with acute occlusion of a proximal cerebral artery, a disabling neurologic deficit, and either initiation of therapy within 8 hours of onset or initiation of therapy beyond 8 hours if imaging demonstrated substantial residual penumbral tissue at risk were treated at a tertiary Comprehensive Stroke Center (the UCLA Stroke Center). Thrombus was removed by an endovascular mechanical embolectomy device (Merci® Retriever System, Concentric Medical, Mountain View, CA) after placement by angiographic catheter into the occluded intracranial carotid artery, middle cerebral artery or vertebral-basilar artery under fluoroscopic guidance. Our results show that the large majority (20 of 25) of extracted thrombi have similar histologic architecture, a complex of layered, sometimes serpentine, lengths of fibrin:platelet deposits interspersed with linear streaks of nucleated cells. This histology was prevalent with both cardioembolic and atherosclerotic etiologies, indicating the same pathogenetic influences of blood flow and shear in thrombus formation. This histologic pattern among thrombi was present in both the internal carotid artery (ICA) and the middle cerebral artery (MCA). Clots composed uniformly of erythrocytes were uncommon (3 of 25) and were observed only with incomplete extractions, suggesting that sampling was of the proximal thrombus tail where post-occlusion thrombosis had occurred under conditions of stagnant flow. Calcifications or cholesterol were not present. Thrombus size, not histology, predicted the site of arterial occlusion, with no thrombus larger than 3 mm width causing stroke limited to the MCA and no thrombus larger than 5 mm width removed from the ICA. Fungus-containing thrombus was extracted from one patient who had mycotic valvular disease, and an unusual complication occurred in another case, namely, scraping of a small atheroma and attached intima from the MCA, albeit without clinical consequence. We conclude that thromboemboli that cause acute ischemic stroke are of similar, complex structure, regardless of macroscopic dimensions, and are similarly influenced by blood flow, whether the primary etiology is cardioembolic or atherosclerotic. Embolus size is the critical aspect that determines its ultimate destination, those of more than 5 mm width appearing to bypass the cerebral vessels entirely. The mixed fibrin:platelet pattern present in the preponderance of thromboemboli provides foundation for the success of both antiplatelet and anticoagulant treatment strategies in stroke prevention.

Intraoperative lytic therapy: agents and methods of administration.

Intraoperative intraarterial thrombolysis is a valuable adjunct for the removal of residual arterial thrombi after mechanical thromboembolectomy. Early reports by some investigators indicated high rates of bleeding complications, most likely caused by inappropriately high doses of plasminogen activators infused over long periods of time, which led to systemic lytic effects. Animal models and controlled human experiments subsequently have shown the potential efficacy and safety of intraarterial thrombolysis. Since urokinase (UK) has been withdrawn from the market, recombinant tissue-type plasminogen activator (rt-PA) has become the plasminogen activator of choice. Reteplase and other plasminogen activators may be beneficial (and safe); however, data on intraoperative use currently are not available. The most common methods of delivery into the distal arterial tree are bolus infusion with inflow occlusion, drip infusion after restoration of arterial inflow, and the isolated limb perfusion technique. The number of distal vessels involved, the amount of residual thrombus, and severity of ischemia guide the dose of plasminogen activator, volume of perfusate, and the technique and duration of infusion.

Acute peripheral arterial occlusion: solving a clinical problem

This paper gives an overview of the endovascular treatment of acute limb ischemia. Clinical findings and selection criteria will be discussed briefly. The advantages and disadvantages as well as the clinical success rates and complications of pharmacologic and mechanical thrombolysis and aspiration thromboembolectomy will be covered.

Mechanical Thromboembolectomy in Acute Embolic Peripheral Arterial Occlusions with Use of the Angiojet Rapid Thrombectomy System

Mechanical Thromboembolectomy in Acute Embolic Peripheral Arterial Occlusions with Use of the Angiojet Rapid Thrombectomy System

The Use of the Fogarty Catheter in 1998

Catheter-mediated thromboembolectomy has evolved over the last three decades along with changes in vascular disease patterns. As in situ arterial thrombosis has become more common both in natural arteries and prosthetic grafts, changes in mechanical thromboembolectomy have been necessary to optimize treatment strategies. A variety of devices and techniques are now available for transluminal clot removal including the original thromboembolectomy catheter, newer adherent clot catheters, graft thrombectomy catheters, thru-lumen balloon catheters and methods that involve fragmentation and removal of fresh thrombus by hydrodynamic means.