Safety and Efficacy of Vacuum Assisted Thrombo-Aspiration in Patients with Acute Lower Limb Ischaemia: The INDIAN Trial.

OBJECTIVE: The aim was to evaluate the short term safety and effectiveness of the Penumbra/Indigo aspiration thrombectomy Systems (Penumbra Inc.) in patients with acute lower limb ischaemia. (ALLI). Recently, endovascular vacuum assisted thrombectomy devices, similar to those used in the management of acute ischaemic stroke, have become available for peripheral arteries, but data are still scarce. METHODS: To assess vessel patency, a modified Thrombolysis in Myocardial Infarction (TIMI) classification, called TIPI (Thrombo-aspiration In Peripheral Ischaemia), is proposed. The TIPI flow is assessed at presentation, immediately after treatment with the study device, and after all adjuvant procedures. The primary outcome is the technical success of the thrombo-aspiration with the investigative system, defined as near complete or complete revascularisation TIPI 2 - 3. Safety and clinical success rate were collected at one month. RESULTS: One hundred and fifty patients were enrolled. The mean age was 72.4 years and 73.3% were male. Rutherford grade on enrolment was I in 16%, IIa in 40.7%, and IIb in 43.3% with a mean ankle brachial index of 0.19. Primary technical success (TIPI 2 - 3 flow) was achieved in 88.7% of patients. Adjunctive procedures included angioplasty/stenting of chronic atherosclerotic lesions (n = 39), thrombolysis (n = 31), covered stenting (n = 15), and supplementary Fogarty embolectomy (n = 6). After all interventions, assisted primary technical success was 95.3% (TIPI 2 - 3 in 143/150). No systemic bleeding complications or device related serious adverse events were reported. At one month follow up, one death, and one below the knee amputation were recorded. Primary patency was 92% (138/150), and the re-intervention rate was 7.33%, resulting in an assisted primary and secondary patency of 94% and 99.33%, respectively. CONCLUSION: Results from the INDIAN registry reveal that mechanical thrombectomy using the Indigo system is safe and effective for revascularisation of ALLI as a primary therapy.

Interventional Therapies for Acute Pulmonary Embolism: Current Status and Principles for the Development of Novel Evidence: A Scientific Statement From the American Heart Association.

Pulmonary embolism (PE) represents the third leading cause of cardiovascular mortality. The technological landscape for management of acute intermediate- and high-risk PE is rapidly evolving. Two interventional devices using pharmacomechanical means to recanalize the pulmonary arteries have recently been cleared by the US Food and Drug Administration for marketing, and several others are in various stages of development. The purpose of this document is to clarify the current state of endovascular interventional therapy for acute PE and to provide considerations for evidence development for new devices that will define which patients with PE would derive the greatest net benefit from their use in various clinical settings. First, definitions and limitations of commonly used risk stratification tools for PE are reviewed. An adjudication of risks and benefits of available interventional therapies for PE follows. Next, considerations for optimal future evidence development in this field are presented in the context of the current US regulatory framework. Finally, the document concludes with a discussion of the pros and cons of the rapidly expanding PE response team model of care delivery.

Interventional magnetic resonance imaging guided carotid embolectomy using a novel resonant marker catheter: demonstration of preclinical feasibility.

To assess the visualization and efficacy of a wireless resonant circuit (wRC) catheter system for carotid artery occlusion and embolectomy under real-time MRI guidance in vivo, and to compare MR imaging modality with x-ray for analysis of qualitative physiological measures of blood flow at baseline and after embolectomy. The wRC catheter system was constructed using a MR compatible PEEK fiber braided catheter (Penumbra, Inc, Alameda, CA) with a single insulated longitudinal copper loop soldered to a printed circuit board embedded within the catheter wall. In concordance with IACUC protocol (AN103047), in vivo carotid artery navigation and embolectomy were performed in four farm pigs (40-45 kg) under real-time MRI at 1.5T. Industry standard clots were introduced in incremental amounts until adequate arterial occlusion was noted in a total of n=13 arteries. Baseline vasculature and restoration of blood flow were confirmed via MR and x-ray imaging, and graded by the Thrombolysis in Cerebral Infarction (TICI) scale. Wilcoxon signed-rank tests were used to analyze differences in recanalization status between DSA and MRA imaging. Successful recanalizations (TICI 2b/3) were compared to clinical rates reported in literature via binomial tests. The wRC catheter system was visible both on 5° sagittal bSSFP and coronal GRE sequence. Successful recanalization was demonstrated in 11 of 13 occluded arteries by DSA analysis and 8 of 13 by MRA. Recanalization rates based on DSA (0.85) and MRA (0.62) were not significantly different from the clinical rate of mechanical aspiration thrombectomy reported in literature. Lastly, a Wilcoxon signed rank test indicated no significant difference between TICI scores analyzed by DSA and MRA. With demonstrated compatibility and visualization under MRI, the wRC catheter system is effective for in vivo endovascular embolectomy, suggesting progress towards clinical endovascular interventional MRI.

Surgical Treatment of Acute Massive Pulmonary Embolism.

Massive pulmonary embolism (MPE) is a life-threatening condition. The management of MPE has changed over the course of the last few years. Since the emergence of thrombolytic therapy, only a few patients remain amenable for surgical treatment. Currently, surgical embolectomy is advised only in very specific indications. This chapter will review the background, history, indications, surgical technique and results of surgical pulmonary embolectomy in patients with MPE.

Use of a Modified Cardiopulmonary Bypass Circuit for Suction Embolectomy with the AngioVac Device.

The AngioVac suction cannula and circuit were designed for the percutaneous removal of soft thrombus and emboli in procedures requiring extracorporeal circulatory support. We describe a modification of the AngioVac suction catheter and cardiopulmonary bypass (CPB) circuit to effectively remove thrombus while maintaining the ability to rapidly initiate full CPBs during a medical crisis. This article will discuss the design concepts of the modified circuit as well as procedural protocols and considerations. The design modifications of incorporating an oxygenator, reservoir, and bridge allow for an increased flexibility that allows adaption to veno-venous extracorporeal membrane oxygenation or full CPB support when required for oxygenation or hemodynamic support.

Left main coronary artery embolization in an 11-year-old girl due to inflammatory myofibroblastic tumor of the mitral valve.

This report describes a rare case of a subtotal left main coronary artery occlusion from mitral valve tumor embolization in an 11-year-old African American girl. This case is the first to report isolated ST segment elevation in lead aVR as a sign of a subtotal left main coronary artery occlusion in the pediatric population. In our case, we report a rare case of inflammatory myofibroblastic tumor of the mitral valve presenting with acute myocardial infarction due to embolization into the left main coronary artery. Coronary intervention was successfully performed using an aspiration catheter. Inflammatory myofibroblastic tumor usually presents as a solitary pulmonary nodule. Intracardiac involvement has been rarely reported. Despite the benign nature of the tumor, fatal presentations can occur. Early recognition and rapid intervention can be lifesaving in these patients.

Early Experience with AngioVac Aspiration in the Pulmonary Arteries.

Five consecutive cases in which the AngioVac aspiration cannula was used for the management of pulmonary embolism (PE) were retrospectively reviewed. Four cases (80%) presented with massive PE, and two (40%) were technically successful (reduction in Miller index ≥ 5). Four patients (80%) died at a mean of 7.3 days after the procedure, including one death related to right ventricular free wall perforation. Although the AngioVac aspiration cannula has shown clinical promise in a variety of clinical applications, early experience in the pulmonary arteries has shown limited success, and further study and careful patient selection are required.

Foot Embolization During Limb Salvage Procedures in Critical Limb Ischemia Patients Successfully Managed With Mechanical Thromboaspiration: A Technical Note.

PURPOSE: To illustrate the use of a mechanical thromboaspiration device originally designed for clot retrieval in acute stroke in the treatment of acute distal embolism occurring during percutaneous revascularization of the femoropopliteal and below-the-knee arterial segments. TECHNIQUE: The Penumbra system was adapted for aspiration of thrombus in the distal foot arteries as a standalone device. The 2 over-the-wire, tapered lumen catheters have long working lengths (139 cm for the 4MAX to 153 cm for the 3MAX) that allow advancement below the ankle even with a retrograde contralateral approach. Once the occluded arterial segment is reached, the catheters are connected to the dedicated pump for continuous vacuum aspiration. The use of the device is illustrated in 3 diabetic patients (1 woman and 2 men; ages 88, 70, and 73 years, respectively) undergoing limb salvage procedures who experienced distal embolization that would have seriously jeopardized the foot circulation. The lumens of the occluded arteries were restored without complication. CONCLUSION: While further evaluation in a larger cohort of patients is needed, this initial experience using the Penumbra system in the peripheral vasculature suggests that this is a rapid, effective approach to address intraprocedural foot embolization and avoid possible grave clinical sequelae.

The Year Embolectomy Won: a Review of Five Trials Assessing the Efficacy of Mechanical Intervention in Acute Stroke.

Embolectomy with stentriever devices is the newest treatment for acute stroke. Since 1995, treatment of acute stroke has been limited to a 4.5-h window with the use of intravenous tissue plasminogen activator (tPA). Five articles have been published in 2015 with the results supporting the paired treatment of tPA and embolectomy. This has also expanded the treatment window to greater than 4.5 h and produced evidence which will guide selection of patients that will benefit most from this therapy. This article will compare and contrast this most recent evidence.

Histopathology of embolic debris captured during transcatheter aortic valve replacement.

BACKGROUND: Recent transcatheter aortic valve replacement studies have raised concerns about adverse cerebrovascular events. The etiopathology of the embolized material is currently unknown. METHODS AND RESULTS: A total of 40 patients underwent transcatheter aortic valve replacement with the use of a dual filter-based embolic protection device (Montage Dual Filter System, Claret Medical, Inc). Macroscopic material liberated during the transcatheter aortic valve replacement procedure was captured in the device filter baskets in 30 (75%) patients and sent for histopathologic analysis. The captured material varied in size from 0.15 to 4.0 mm. Amorphous calcified material (size, 0.55-1.8 mm) was identified in 5 patients (17%). In 8 patients (27%), the captured material (size, 0.25-4.0 mm) contained valve tissue composed of loose connective tissue (collagen and elastic fibers) with focal areas of myxoid stroma, with or without coverage by endothelial cells and intermixed with fibrin. In another 13 (43%) patients, collagenous tissue, which may represent elements of vessel wall and valvelike structures, was identified. In 9 patients (30%), thrombotic material was intermixed with neutrophils (size, 0.15-2.0 mm). Overall, thrombotic material was found in 52% of patients, and tissue fragments compatible with aortic valve leaflet or aortic wall origin were found in 52% (21/40) of patients. CONCLUSIONS: Embolic debris traveling to the brain was captured in 75% of transcatheter aortic valve replacement procedures where a filter-based embolic protection device was used. The debris consisted of fibrin, or amorphous calcium and connective tissue derived most likely from either the native aortic valve leaflets or aortic wall.

New stent retriever devices.

Acute ischemic stroke (AIS) is among the leading causes of adult death and number one cause of severe disability in the United States. In 1995 physicians had their first available Food and Drug Administration (FDA) approved treatment for AIS in the form of intravenous tissue plasminogen activator (IV-tPA). Since then, there has been an explosion of interest into endovascular mechanical thrombectomy as a potential treatment of stroke. Beginning in 2004 with the Merci Retriever, there have been multiple devices tested for this purpose. In 2012, the FDA approved two new devices-the Trevo Pro and Solitaire stent retrievers-after they were shown to have superior rates of recanalization when compared to the Merci device. In this article we will highlight the similarities and differences in the devices themselves, and the trials that brought them into use. Lastly, we will briefly touch on the future of mechanical embolectomy and considerations for future trial designs and patient selection.

Effects of sex on mechanical embolectomy outcome.

Given that women have demonstrated a greater margin of benefit than men from treatment with thrombolytics in certain acute stroke trials, the current study explored whether this sex effect extends to mechanical embolectomy and can be explained by revascularization rate. The study included the 305 patients enrolled in the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI trials. Demographic, risk factor, and procedural characteristics were evaluated in women and men. Odds ratios for outcomes by sex were compared in patients with revascularization and those without revascularization, defined as a Thrombolysis in Myocardial Infarction score of 2-3 at the end of the procedure. Outcomes included a modified Rankin Scale (mRS) score of 0-2 and mortality at 90 days, as well as the presence of symptomatic intracranial hemorrhage (sICH). Patient and procedural characteristics did not differ between women and men except for mean age (women, 70.1 years; men, 64.8 years; P = .003), hypertension (women, 78.0%; men, 65.5%; P = .021), and number of vertebrobasilar occlusions (women, 8/159 [5.0%]; men, 20/146 [13.7%]; P = .01). Revascularization was significantly associated with favorable outcomes in both women and men (P < .0001), and rates of favorable outcome, mortality, and sICH did not differ between women and men when the vessel was revascularized. Likewise, mechanical embolectomy with the Merci Retriever was not associated with different outcomes in women and men when the vessel was revascularized. Our data suggest that the sex differences seen in thrombolytic trials might be due to factors other than immediate postprocedural large vessel opening.

Mechanical thrombectomy with the Solitaire AB device in large artery occlusions of the anterior circulation: a pilot study.

BACKGROUND AND PURPOSE: To describe the safety and effectiveness of a self-expanding and fully retrievable stent (Solitaire AB; ev3 Inc, Plymouth, MN) in revascularization of patients with acute ischemic stroke. METHODS: Prospective, single-center study of 20 patients with an acute ischemic stroke attributable to a large artery occlusion of the anterior circulation within the first 8 hours from symptoms onset (median National Institutes of Health Stroke Scale, 19 [interquartile range, 15-23]). The occlusion site was middle cerebral artery in 12 patients, proximal internal carotid artery/middle cerebral artery tandem occlusion in 3 patients, and terminus internal carotid artery in 5 patients. Thrombectomy was used as rescue therapy in 2 patients who were refractory to intra-arterial plasminogen activator, and in 3 patients in whom successful recanalization with the MERCI retriever was not achieved. RESULTS: Successful revascularization defined as thrombosis in cerebral ischemia grade 2b or 3 was achieved in 18 of 20 (90%) treated vessels, and 16 patients showed immediate restoration of flow after stent deployment. The mean number of passes for maximal recanalization was 1.4, and the median (quartiles) time from groin puncture to recanalization was 50 (38-71) minutes. No case required adjuvant therapy after deployment of the embolectomy device. No significant procedural events occurred. Symptomatic intracranial hemorrhage was found in 2 (10%) patients, 4 (20%) patients died during the 90-day follow-up period, and 45% of patients showed good functional outcome at 3 months (modified Rankin Scale score

Therapy for acute high-risk pulmonary embolism: thrombolytic therapy and embolectomy.

PURPOSE OF REVIEW: Acute pulmonary embolism remains associated with high morbidity and mortality rates despite currently available therapeutic options. This review outlines the most recent changes in this field and summarizes the main indications for thrombolytic therapy and surgical or catheter-based embolectomy in patients with high-risk pulmonary embolism. RECENT FINDINGS: There have been no major advances in therapy for high-risk pulmonary embolism over the past few years. The main change concerns risk stratification, which now classifies patients as high risk versus intermediate or low risk, replacing the former terminology of acute massive, submassive or nonmassive pulmonary embolism. Risk stratification is now oriented toward evaluation of the risk of early pulmonary embolism-related death. Thrombolysis is the mainstay of therapy in high-risk pulmonary embolism. Surgical embolectomy has become more frequent, due to the reduction in mortality risk associated with this technique. However, it remains limited to patients unsuitable for thrombolysis. Catheter-based embolectomy is reserved for situations in which neither thrombolysis nor surgical embolectomy is possible. SUMMARY: Thrombolytic treatment should be first-line therapy in patients with high-risk pulmonary embolism presenting with cardiogenic shock and/or persistent arterial hypotension, with very few absolute contraindications. Both surgical and catheter pulmonary embolectomy are valuable therapeutic options in patients in whom thrombolysis is absolutely contraindicated or has failed.

Mechanical embolectomy for large vessel ischemic strokes: a cardiologist's experience.

INTRODUCTION: Large vessel acute ischemic stroke has a poor outcome. Intravenous (IV) thrombolysis is often contra-indicated and if given, usually ineffective. Mechanical embolectomy is an option in these patients and may be performed by an interventional cardiologist experienced in carotid interventions. METHOD: Consecutive stroke patients were assessed by the stroke physician and, if eligible, referred for possible mechanical embolectomy using the Merci retriever. All procedures were done by a single cardiologist. Patient information, procedural characteristics and clinical outcomes at 90 days were collected by retrospective chart review. RESULTS: A total of 22 patients were referred for emergency cerebral angiography with 17 undergoing mechanical embolectomy. The mean National Institute of Health Stroke Scale (NIHSS) score was 20.1 and the mean stroke duration was 284 min. Recanalization was successful in 15 (88%) patients. Ten patients (59%) had a good outcome (modified Rankin Score ≤2 at 90 days) and four died (mortality 23%). Three patients had significant intra-cerebral hemorrhage. There were no other major adverse events. CONCLUSIONS: For patients with large vessel occlusion strokes where IV thrombolysis was either contra-indicated or had failed, mechanical embolectomy performed by an interventional cardiologist had a high recanalization rate with an acceptable clinical outcome and safety profile.

Therapy of acute massive pulmonary embolism associated with Klippel-Trenaunay syndrome.

Acute massive pulmonary embolism (PE) is a life-threatening event. Before the era of cardiopulmonary bypass, acute pulmonary embolectomy had been historically attempted in patients with severe hemodynamic compromise. The Klippel-Trenaunay syndrome (KTS) represents a significant life-long risk for major thromboembolic events. We present two young patients with Klippel-Trenaunay syndrome who survived surgical embolectomy after massive PE and cardiopulmonary resuscitation, with good postoperative recovery. Even though the role of surgical embolectomy in massive PE is not clearly defined, with current technology it can be life saving and can lead to a complete recovery, especially in young patients as described in this study.

Hybrid procedures for acute limb ischemia.

The most efficient treatment for acute arterial embolism is operative embolectomy using Fogarty's balloon catheter, especially if a single large artery is involved. Unfortunately, although the early surgical success of arterial thromboembolectomy often seems acceptable, the early clinical outcome still remains unsatisfactory. This may be related to the incomplete restoration of perfusion (i.e., residual thrombus in distal vessels not reached by the balloon catheter thromboembolectomy), propagation of residual thrombi or presence of underlying steno-occlusive lesions. In such a situation a meticulous intraoperative assessment of the adequacy of clot removal is decisive. Residual thrombus, chronic atherosclerotic disease and even vessel injuries secondary to balloon catheter passage can be corrected by endovascular techniques (hybrid procedures). The combination of surgical and endovascular options may overcome the limitations that characterize the traditional approach, and it is likely that in the future many treatments will be a mix of techniques that can be performed by vascular surgeons in the operating room or in a dedicated endovascular suite. This review article summarizes the hybrid treatment options for acute arterial occlusion caused by either embolism or local thrombosis.