Vascular Interventional Radiology: Angioplasty, Stenting, Thrombolysis and Thrombectomy (Medical Rad

leondumoulin.nl: Vascular Interventional Radiology: Angioplasty, Stenting, Thrombolysis and Thrombectomy (Medical Radiology / Diagnostic Imaging).
Table of contents

Although vascular surgeons used to be the main practitioners of aortic grafting, more nonsurgical specialists are now getting involved, primarily due to the development of new transcatheter devices for delivery of vascular prostheses.

Percutaneous Transluminal Balloon Angioplasty

At first, the use of endoluminal devices was reserved for patients who had concomitant illnesses or other conditions that increased the risk of conventional surgery. The early prostheses were relatively inflexible and required an introducing femoral sheath with a F internal diameter. Their structures are either completely stent-supported or stented only at the level of attachment.

Some of these devices consist of fabric grafts that are supported throughout their length by self-expanding metal stents to minimize kinking and migration. Stainless steel and nitinol the latter of which has thermal memory characteristics are the most common materials used for stents. Some investigators have reported that fully supported grafts offer a higher degree of immediate and late success. The stent grafts are either self-expandable 28,29 or balloon-expandable.

Which of these materials and designs will ultimately produce superior long-term results should be revealed when ongoing clinical studies 26—32 are completed. In , well over 4, endoluminal abdominal aortic aneurysm repairs were performed with various devices world-wide Table II. Both are over-the-wire systems that require bilateral femoral artery access.

The Ancure stent graft Fig. The graft is bifurcated and thus has no intragraft junctions. The main device is delivered through a F introducer sheath; a F sheath is required to facilitate the deployment of the contralateral iliac limb. The graft is attached via a series of hooks that are located at the proximal aortic end and at both iliac ends.

The hooks are seated transmurally in the aorta and the iliac arteries, initially by minimal radial force, and then affixed by low-pressure balloon dilation. Radiopaque markers are located on the body of the graft for correct alignment and positioning. The AneuRx device Fig. The graft is made of thin-walled woven polyester that is fully supported by a self-expanding nitinol exoskeleton. Attachment is accomplished by radial force at the attachment sites, which causes a frictional seal. The main bifurcated body is delivered through a F sheath, and the contralateral limb requires a F sheath.

The body of the graft has radiopaque markers that facilitate correct alignment and positioning. Although substantial improvements have been made in stent grafts since the original procedure by Parodi and coworkers, 23 further follow-up in current trials is needed to determine the exact usefulness of this procedure for the treatment of AAAs. Some of the devices listed in Table I are currently undergoing clinical evaluation in the United States, and several have already been released for clinical use in other countries.

A principal goal of treatment for acute limb ischemia is rapid restoration of blood flow to the ischemic region before the occurrence of irreversible changes. Intravenous infusion of exogenous plasminogen activators—specifically, streptokinase—was attempted nearly 40 years ago for the treatment of peripheral arterial occlusion. Reasons for using thrombolytic therapy for arterial thrombotic disease are listed below:. Thrombolytic agents include streptokinase, acylated plasminogen streptokinase complex, urokinase no longer available , pro-urokinase, and recombinant tissue plasminogen activator rt-PA-alteplase and r-PA-reteplase.

All of these agents induce a systemic fibrinolytic state. In comparative studies on the treatment of arterial thrombosis, 33—41 streptokinase, urokinase, rt-PA, and pro-urokinase have been shown to be more effective than heparin alone in lysing the thrombus. A recent report by McNamara 42 suggests that r-PA may have a clinical efficacy similar to that of rt-PA, but with less bleeding.

Techniques for Revascularization

Early studies concerning the use of thrombolytic agents revealed that lysis is more likely to be successful if the thrombosis is recent and involves proximal vessels. Comparative studies of streptokinase, urokinase, and rt-PA have shown that rt-PA provides equal success in thrombolysis, but with a higher rate of major bleeding.

Urokinase, which had been the most frequently used thrombolytic agent, was recently removed from the market because of concerns about possible hepatitis contamination. Thrombolytic agents have been infused both systemically and locally. The systemic use of thrombolytic agents has been associated with severe bleeding complications. Several investigators have shown the usefulness of a guidewire traversal test to assess the outcome of thrombolysis. A variety of multi-sidehole catheters and infusion wires are available for local administration of thrombolytic agents.

Some of the administration techniques that have been tried include bolus lacing an initial bolus of the agent is given over a short period of time throughout the length of the thrombus , 34,38 pulsed-spray a lytic agent is injected through a multi side-hole catheter using high-pressure intermittent pulses , 39 and continuous infusion of a thrombolytic agent over a longer period of time hours to days.

The dosage and duration of infusion of thrombolytic agents depend on the indication; the agent used; the route of administration; the amount, age, and surface area of the thrombus; and the degree of ischemia. In general, the fresher the thrombus, the more effective the thrombolysis will be.

The more severe the degree of ischemia, the more important it is to achieve rapid lysis. Rapidity of thrombolysis is increased by high-dose regimens; however, the complication rates may also increase. Several investigators 37—40 have shown the benefit of concomitant anticoagulation and thrombolysis. Concomitant anticoagulation with heparin reduces thrombus formation around the catheter and retards thrombus propagation and reocclusion of the treated vessel segment, particularly in a proximal vessel that has low blood-flow above the occlusion.

However, the addition of heparin can increase the severity of a bleeding complication. The likelihood of success of thrombolysis depends on the factors listed in Table III. The end points of thrombolysis are as follows: The selection of patients for thrombolysis depends on the presenting symptoms, medical history, physical findings, and objective laboratory test results. After the diagnosis of thrombosis has been established, it is essential to evaluate the indications, contraindications, risk factors, and likelihood of success.

If thrombolysis is deemed a reasonable choice for therapy, the site of vascular access can be carefully selected and angiography performed. After the angiographic findings have been evaluated and the likelihood of success has been determined, the type of equipment and the dosage and type of thrombolytic agent can be selected. Before the initiation of treatment with thrombolytic agents, possible hypercoagulable conditions should be considered:. The presence of any of the above conditions is a contraindication to the use of thrombolytic therapy.

Extensive experience over the past decade has led to increased acceptance of selective intra-arterial thrombolytic therapy for peripheral arterial occlusions as an adjunct to definitive revascularization procedures. Although newer infusion techniques have substantially decreased treatment times, they remain at around 24 hours for lower-extremity occlusions. Work continues on the optimization of infusion methods and on the development of new drugs and dosages in order to shorten treatment times.

A number of mechanical devices have been developed to disrupt and remove freshly formed thrombus from the circulation Table IV. It appears that these devices are of most value when used to remove thrombi of recent onset. A brief description of some of the more promising devices follows. Several studies 43—47 have shown this device to be effective in treating thrombus-containing lesions in the peripheral and coronary circulation.

It has been used successfully in native arteries, veins, saphenous vein grafts, prosthetic grafts, and renal dialysis shunts.

Review: Interventional radiology in peripheral vascular disease

The AngioJet is currently approved for use in vessels larger than 2. It can be used for thrombus removal and for breaking apart and removing unorganized thrombus from arteriovenous access. Negative pressure pulls the thrombus into the heparinized saline stream, resulting in microfragments that are discharged through the outflow lumen into the collection bag. Early reports from European trials 48,49 suggest a possible use for this device in thrombus-containing lesions and degenerated vein grafts. Currently, the device is investigational. This device is approved in the United States for use in obstructed renal dialysis grafts.

Despite improvements in long-term outcomes after PTA and stenting of the peripheral vessels, restenosis remains a significant problem—particularly in long lesions, small-diameter vessels, and restenotic lesions. None of these approaches has yet been successful in solving this problem. Vascular radiation for the prevention of restenosis after PTA and stenting is a new frontier in the field of peripheral interventions.

The 1st experience with in vivo endovascular radiation therapy was reported in by Friedman and colleagues 52 when they attempted to prevent the development of atherosclerosis. Various types of radiation therapy have been tried to prevent restenosis after angioplasty, stenting, or both Table V.

One consideration is that large-diameter peripheral vessels require higher energy sources than the coronary vessels do. To date, no randomized trial with long-term follow-up after external beam radiation has been performed to determine the long-term results and the consequences of the radiation to the adjacent tissues. Intravascular radiation therapy with various beta and gamma sources has been studied more extensively than has external beam radiation. A large number of animal investigations 54,55 and a few clinical trials 56,57 have established the ability of ionizing radiation to inhibit vascular smooth-muscle-cell proliferation associated with restenosis.

Recently, several studies 58—60 have shown that localized irradiation of the angioplasty site by intraluminal delivery of low-dose beta-particle irradiation as well as gamma irradiation inhibits smooth-muscle-cell migration and proliferation in vitro and in vivo. A number of isotopes have been tested and several others are being considered for future studies Table VI.

Two of the most controversial issues surrounding the delivery of intravascular radiation involve the preference of beta- or gamma-emitting radioisotope sources and the importance of source-centering in the arteries. Improper centering of the catheter-based solid source off by as little as 0. The consequences of these errors are considerably worse with beta emitters than with gamma emitters. However, because beta emitters deposit a large portion of their energy locally, these isotopes have substantial safety advantages over the gamma emitters for both the operator and the patient.

Efforts to make use of beta radioisotopes in solution await the development of an appropriate compound with an adequate biodilution profile to safely handle the potential intravascular release of radioisotope-containing liquid. The 1st clinical trial involving endovascular radiotherapy was started in by Liermann and co-workers 61 in an effort to reduce the restenosis rate following PTA in peripheral vessels. Their 6-year experience May to June was described by Schopohl and co-authors Frankfurt trial.

More recently, in a randomized trial comparing PTA and brachytherapy for superficial femoral artery lesions, Pokrajac's group 63 reported a restenosis rate of The PARIS Peripheral Arteries Radiation Investigational Study trial 64 is currently evaluating the safety, feasibility, and efficacy of endovascular brachytherapy to prevent restenosis in the superficial femoropopliteal arteries immediately after PTA without stenting. Endovascular brachytherapy is administered through a balloon-centering catheter system using an IrHDR source delivered to the target site by a remote afterloader.

Twenty-seven patients completed Phase II the 6-month angiographic follow-up. Brachytherapy for treatment of peripheral arterial disease to prevent restenosis after an interventional procedure is in the early developmental stages. Various isotopes are being tested in an effort to minimize the radiation exposure to patients and personnel and to reduce the dose delivery in the near field.

This improves the depth of dose delivery, especially for large vessels. New techniques, such as radioactive liquid- or gas-filled balloons that improve dose delivery, are being investigated. Potential sites for brachytherapy include the superficial femoral arteries, popliteal arteries, tibio-peroneal arteries, hepatic vascular system-TIPS transjugular intrahepatic portosystemic shunt , arteriovenous dialysis grafts, renal arteries, and carotid arteries.

Vascular complications after endovascular treatment can cause morbidity and even death, and can increase the total cost of the procedure by prolonging the patient's hospital stay. Prevention of vascular complications is therefore essential to optimize the outcome of interventional procedures. These devices are commonly used for larger sheath sizes 8 to 16 F. The choice of technique is affected by patient size, the availability of a specific device, and the expertise of the individual using the device.

Arterial compression is time consuming and labor intensive. The patient is often immobilized for an extended period of time; consequently, back pain and urinary retention may occur. Movement during compression can induce a local hematoma. In addition, anticoagulation therapy must be interrupted for this method of obtaining hemostasis. Lately, there has been considerable interest in new methods to assist with hemostasis at the time of arterial catheter removal.

This interest stems from an increased emphasis on patient mobilization and discharge on the day of the procedure. Recently introduced vascular hemostatic devices, deployable without compression and anticoagulation reversal, offer an alternative approach. The role of catheter techniques for arterial entry closure is evolving. Multiple devices are available, including collagen plugs, bioabsorbable pledgets, and vessel suturing devices, all of which can be introduced through specially designed catheters. The collagen, unaffected by antiplatelet or anticoagulant agents, attracts and activates platelets, rapidly forming a glue-like plug at the arterial puncture site and obliterating the subcutaneous tunnel.

This reduction in time to hemostasis was independent of the heparin load. Sanborn and colleagues, 69 in a multicenter randomized trial, found that major complications occurred in 1. Paul, Minn is a specially engineered bioabsorbable anchor collagen sponge that is deployed through a sheath, which is then drawn tightly against the arteriotomy. The device consists of 3 completely bioabsorbable components: When deployment of the anchor has been confirmed, the carrier tube and the insertion sheath are withdrawn and the tamper tube appears. This device is used to ensure proper positioning of the collagen.

Atension spring is then applied over the suture, the suture is cut, and the carrier tube and the insertion sheath are removed. All the components are fully absorbed by the body in 60 to 90 days. This device is available in sizes from 6 to 10 F and is indicated for both diagnostic and interventional procedures. More recently, in patients, the U. The incidence of pseudoaneurysms and arteriovenous fistulae was the same in both groups. The worst complication associated with the Angio-Seal device is anchor failure with subsequent distal embolization. Thus far, this complication has occurred once in the U.

Insertion of this device may be limited in patients who are obese, because the relatively short length of the tamper tube may make collagen compression difficult. A longer tamper rod is being designed to correct this problem. As currently designed, the device cannot be used during procedures that require catheters larger than 8 F.

Larger sizes are being developed to extend device applicability to procedures that require larger sheaths. In addition, repuncture of the artery after device placement has not been studied in human beings. At this time, the manufacturer does not recommend reentry into an artery sealed with this device until 90 days have passed, in order to allow full collagen absorption.

Complication rates were similar for both devices. The Prostar device is now being used in an unusual, off-label fashion that allows safe percutaneous access and closure of access sites up to 16 F. This method, described by Haas and colleagues 73 and by Krajcer and colleagues, 74,75 calls for placement of the Prostar device sutures before sheath placement.

All operators must wear masks, caps, and eye protection to prevent accidental operator contamination. Proper procedural technique includes adequate injections of cerebral vasculature including the aortic arch, and use of multiple views with appropriate radiographic angulation for visualization of the cerebral vascular structures. Patients should have adequate monitoring including hemodynamic monitoring of basic vital signs blood pressure, heart, rate, respiratory rate, and oxygen saturation along with frequent neurological checks, which must be documented in flow sheets during the procedure.

Post-procedural hemostasis may be achieved by several means including manual pressure, mechanical compression devices, or percutaneous closure devices. Patients should be monitored after procedure for hematoma and pseudoaneurysms, and event rates of each method and each device must be tracked. Antiplatelet agents, including aspirin and Plavix, do not need to be withheld before cerebral angiography.

If necessary, warfarin may be reversed with FFP or vitamin K as per pharmacy protocol. The stroke interventionalists must operate within a structured framework of support staff and services from the EMS, ED, radiology, and stroke interventional laboratory. AIS patients, from the time of first contact in the field by EMS, need to be triaged according to treatment modality, either IV t-PA, stroke intervention, or medical management focused on secondary prevention. In efforts to improve outcomes and reduce mortality in AIS patients, national guidelines, protocols, and algorithms have been developed and organized into a systems operation for facilitating the selection of patients eligible for IV t-PA administration.

Fifty-three international trials in the past several decades, including the NINDS and ECASS trials [ 56 , 57 ], demonstrate a significant reduction in 3-month mortality and morbidity for stroke patients who undergo recanalization. In addition, the writing committee further endorses the establishment of clear algorithms and care paths for identifying and managing stroke patients eligible for interventions via catheter-based treatment modalities fig.

All medical staff, including physicians, nursing, and ancillary staff, must be educated in such protocols, and a system must be established where alert system may be activated easily and rapidly. ED-based rapid brain attack triage algorithm for identification of patients eligible for stroke intervention. Algorithm courtesy of Texas Stroke Institute. Patient's with contrast allergies should receive nonionic contrast and premedicated with steroids or antihistamines, as per pharmacy protocol of the institution. Patients with renal insufficiency should be hydrated before and after procedure, and acetylcysteine should be considered in necessary circumstances.

Fasting patients with diabetes mellitus should receive a reduced dose of insulin in the morning of the procedure. Diabetes patients treated with metformin who have mild renal insufficiency rarely have been reported to develop profound lactic acidosis after receiving radiographic contrast. Metformin dose should be held on the day of the procedure and not started until creatinine stabilizes usually 48 h after the procedure.

Radiotherapy can result in certain inevitable side effects, radiation-induced cutaneous side effects that include acute and chronic dermatitis, alopecia, and systemic side effects. Damage may occur at gross and molecular levels. Changes usually occur weeks after exposure, are usually self-limiting and tend to be largely temporary, and transiently resolve with good prognosis after 6 months [ 62 , 63 ]. These adverse effects are a direct result of radiation dose accumulation, and certain precautions should be kept in mind.

Stroke interventionists should be aware of these effects and strict adherence to maximum radiation dose policies should be maintained. Conditions such as the pediatric patient or pregnancy require special considerations. The pediatric population is particularly vulnerable to certain complicated cerebrovascular diseases such as sickle cell disease, arteriovenous malformations, moyamoya, and vasculitis, to name a few [ 64 ]. Endovascular procedures are viable options for diagnostics and therapeutics.

Goals of care are to define intra- and extra-cranial vasculature and hemodynamics, as well as provide therapeutic benefits. Stroke interventionalists are highly specialized and exist in scarce ratios to serve patient populations, and pediatric expertise and volume are even scarcer. Children under the age of 18 years of age must undergo informed consent from parent or guardian. Patients appropriate for outpatient scheduled procedures must be selected carefully, and overnight admission for monitoring should be considered based on the condition of the patient.

Early discharge for both pediatric and pregnant patients must factor in age and weight, parent or patient reliability, travel time and distance, duration of procedure, time of completion, hemodynamic stability, and estimated blood loss. All procedures on pregnant patients must be performed with full informed consent of the patient as well as in conjunction with obstetricians to help guide the decision-making process. The stroke interventionalists must fulfill and maintain basic requirements in cognitive knowledge, technical expertise, and clinical competency throughout the length of the stroke interventionalist's career to ensure safe and efficient delivery of quality care in potentially life-threatening, critical cerebrovascular diseases [ 31 , 32 , 42 , 65 , 66 ].

Further, the number of stroke interventional laboratories within primary and comprehensive stroke centers are rapidly increasing [ 67 ] without significant oversight. Although the use of specific minimum number of cases to define the quality of operator performance is an imperfect solution to oversee provider and laboratory quality, potential laboratories performing stroke interventional procedures without appropriate oversight and established quality assurance systems pose significant threats to quality of care and patient outcomes.

Further, according to multi-society statement for quality assurance in stroke interventional procedures, increased operator experience is inversely proportional to adverse event rates [ 31 , 32 , 47 ]. Despite the background discipline of the stroke interventionalist, whether neurology, neurosurgery, or neuroradiology, competency and credentialing must be tracked in a standardized uniform manner for each laboratory in order to equally assess the procedural skills and adequacy of every stroke interventionalist.

The diagnostic cerebral angiogram is the cornerstone and foundation for all modalities of interventional stroke therapies, including carotid artery angioplasty and stenting of atherosclerotic vessels, interventional angioplasty and stenting, coiling and embolization of cerebral aneurysms, embolization of epistaxis and vascular malformation procedures.

All recommendations in this current publication comply with existing recommendations and further standardize them for uniform tracking and reporting. Experienced operators should oversee the trainees in diagnostic cerebral angiograms with adequate documentation of formal training maintained as part of records. Trainees should have adequate experience as primary and secondary operator, always under supervision.

The number of procedures, the success, failure, and complication rates, and outcomes should be documented. In compliance with the above multi-society guidelines, trainees must complete at least cerebral diagnostic angiograms for initial credentialing, and 50 cerebral diagnostic angiograms annually for maintenance of operator skills.

Endovascular stent grafting for abdominal aortic aneurysm (AAA) at Mount Sinai Beth Israel in NYC

Intra-Arterial Thrombolysis and Mechanical Thrombectomy. Advanced stroke treatment delivery beyond IV t-PA, i. Due to the scarcity of ACGME-accredited programs requires only 1 year of neurointerventional training , most stroke interventionalists will choose to train in non-ACGME programs duration of 2 years and beyond for better exposure and experience , the SVIN Writing Committee feels that compliance with recent guidelines as well as ACGME-recommended 10 intra-arterial thrombolytic cases are adequate for sufficient experience for stroke intervention [ 43 ].

When performing such procedures, stroke interventionalists must take into special consideration the careful selection of patients eligible for stroke intervention and potential intracerebral hemorrhage resulting in increased mortality and morbidity. Carotid Angioplasty and Stent Placement. The utility of industry-sponsored courses is unclear, and their role in improving operator technical skills has never been validated. Further, an individual stroke interventionalist must comply with regulations from ACGME, institutional, state, and federal guidelines to become fully credentialed and maintain an adequate volume per year per operator to remain fully proficient in carotid angioplasties and stent placement.

Though not all intracranial stenosis patients are eligible for stroke intervention, appropriately selected patients with significant risk of recurrent strokes may be eligible for stroke intervention with intracranial stents [ 71 ]. There are no available data for assessing training requirements for intracranial stents. The SVIN SILC Writing Committee recommends that stroke interventional laboratories document and participate in registries for intracranial stenting, so future data and outcomes may be derived. Quality assurance begins with clinical proficiency among the operators in the stroke interventional laboratory.

The challenges in assessing operator efficiency are multifold, and quality metrics regarding cognitive knowledge, procedural skill, clinical judgment, and procedural outcomes are all equally important factors. In order to ensure quality assurance of the performance of the laboratory unit as a whole, a continuous quality improvement program should be incorporated into the overall design of the stroke interventional laboratory, with key documentation and regular tracking of quality metrics.

These measures are to be overseen by the medical and administrative directors. Outcomes related to complications for diagnostic cerebral angiograms should be very low [ 65 ]. Diagnostic accuracy and adequacy are obviously important parameters but rarely tracked. Major complications, including death, intracerebral hemorrhage, or particulate embolization from procedures should be monitored and evaluated against the severity of the patient population referral bias as well as benchmarks from landmark trials [ 2 , 65 ].

The minimum number of studies required confirming adequate skills in neurological diagnostic catheterization procedures have never been validated. Though risks of diagnostic cerebral angiograms are low, quality improvement measures should be operative and hold precedence. Equipment requirements and management are detailed in a section above see section 2.

Each aspect of the radiographic equipment system should meet standard performance expectations for the safe and quality delivery of patient care. Care paths within systems of stroke care must be organized from the moment of initial contact and triage and follow all the way through discharge disposition. Segments of operation should be divided into prehospital EMS metrics, hospital ED metrics, and laboratory stroke interventional laboratory metrics. From the time of initial contact first medical contact by EMS operators in the field, performance metrics must be tracked, which helps further identify areas of missed opportunities in improving outcomes in stroke patients.

Though national EMS performance metrics in stroke systems, or other similarly organized levels of care such as trauma, have not been clearly established in medical literature, the chain effect of efficient operations at the EMS level trickling down to efficient ED response, admission, and discharge is indirectly implied. Upon arrival of the stroke patient at the appropriate ED, clear concise protocols must be in place for identification of subtype of stroke and rapid delivery of appropriate stroke intervention treatments.

All stroke interventional laboratories must note and document time to imaging, to identify potential improvements or changes that may hinder delivery of stroke interventions to eligible patients. Stroke hospitals must develop taskforces and radiology initiatives for tracking and optimal stroke care delivery.

A means to ensure continuing education and most current cognitive knowledge of all staff involved in the stroke interventional laboratory should be established and adhered to. Key metrics reflecting quality of care should be collected in a systemic manner, have means of statistical analysis of results, and develop an approach to problem solving that involves feedback on the effectiveness of solutions. The SVIN SILC Writing Committee strongly encourages all stroke interventional laboratories to participate in a national registry and help develop quality benchmarks to provide ongoing system for tracking complications and outcomes.

These stroke interventional laboratories for brain attack care are similar to PCI-capable labs for heart attack care. These cerebral angiography laboratories for brain attack care are similar to cardiac catheterization laboratories for heart attack care, and shall strictly adhere to diagnosis of cerebrovascular disorders. These cerebral angiography laboratories may or may not have neurosurgical services and advanced support services such as neurocritical care, renal with hemodialysis, and on call anesthesiology services available, since the complication rates of diagnostic services are low.

Physicians at these cerebral angiography laboratories must have admission privileges in case of complications. These stroke interventional laboratories are ideally associated with a comprehensive stroke center but may be associated with a primary stroke center that has the necessary support services listed above, and may be affiliated with an academic or community-based practice. All supervising physicians, registered radiology assistants, and radiological technologists are responsible for safety in the workplace by keeping radiation exposure of staff and patient.

Operators are to practice the ALARA method As Low As Reasonably Achievable in order to safely assure radiation doses to individual patients are appropriate and minimize the risk of radiation exposure while maintaining adequate image integrity for diagnosis and management of cerebrovascular disease states [ 52 , 73 ]. All personnel and staff working in the stroke interventional laboratory must understand the key principles of occupational and public radiation protection and proper management of radiation dose to patients.

The SVIN SILC Writing Committee recommends that the minimum requirements of annual continuing medical education courses for radiation safety for all staff and physicians within a stroke interventional laboratory as well as compliance with any state or national radiation safety requirements are met.

Radiation safety officer must assist all laboratory staff in policies and procedures for safe handling of radiopharmaceuticals in compliance with the ALARA guidelines. Radiopharmaceutical doses should be tailored for individual patient by protocol. Radiation exposure must be measured by single device monitoring or the two-monitor technique with either X-ray film badges or transluminescent dosimeter badges on a continual basis.

Dosage levels per procedure must be documented and maintained as part of patient medical records for at least 7 years or according to local medical records standards. Operators should always practice standard of care with appropriate shielding and adequate distance. Pregnant workers may continue to work in the stroke interventional laboratory if they choose.

Fetal exposure, as measured by a waist dosimeter, should be no more than 0. Adverse reactions to contrast agents may range from mild allergic reactions to anaphylaxis, renal toxicity, and life-threatening emergency. Factors associated with adverse reactions are history of previous allergy to contrast material, asthma, and other allergies.

Prescreening and prophylactic treatments before contrast administration can prevent potential reactions. Ionic contrast material is usually higher in osmolar content compared to nonionic contrast materials, and generally more toxic. All contrast materials should be used at the lowest possible dose per procedure per patient. Physicians and staff must be aware of such complications to ensure prompt diagnosis and treatment. Four radiation dose metrics should be kept in mind and monitored throughout every stroke interventional procedure: Fluoroscopy time and, more specifically, reference air kerma and kerma-area product are good tools to estimate the risk of radiation injury.

Average doses of stroke interventions nationally by procedure are currently unknown fig. Average radiation doses of stroke interventional procedures over a month period at a comprehensive stroke center. Reference levels are a guide to good practice, but they are neither dose limits nor threshold levels that define competent performance of the operator or the equipment. If the radiation dose for a specific case or the mean dose for a number of cases of a procedure exceeds the reference level, it does not mean that the procedure or procedures have been performed improperly.

Similarly, a mean dose for a procedure that is less than the reference level does not guarantee that the procedure is being performed optimally. All certified stroke interventional procedures must document the above parameters, and a task force must review outliers at regular intervals. Standardized consensus criteria for PCI-capable labs and cardiac catheterization labs have improved access to care and outcomes [ 74 ].

Similarly, brain attack care for LVO's has recently evolved with the completion of several landmark trials in favor of stroke interventions aka endovascular stroke therapy for LVOs [ 2 ]. EMS triage for brain attacks can be simplified similar to heart attacks with the use of stroke severity assessments by EMS en route to a facility [ 75 ]. Stroke intervention is a rapidly evolving field with an exponential potential to impact reduction of mortality and morbidity rates by organizing stroke systems of care, with appropriate EMS triage, and standardized stroke interventional laboratories with the highest quality standards.

As we encounter paradigm shifts in stroke treatments, with accumulating evidence through randomized controlled trials for increasing benefits of stroke interventional treatments for LVO AIS [ 2 ], the stroke interventional community ought to initiate similar organization models and levels of responsibilities of the stroke interventional laboratories. In the absence of benchmarks, organization, and timely delivery of care, stroke interventionalists risk compromising quality of care that can directly impact short and long-term outcomes.

Standardization of SILC criteria is designed to improve stroke and cerebrovascular disease outcomes with appropriate oversight of personnel and logistic components of a stroke interventional laboratory. The 7Ms, manpower, materials, methods, metrics volume , metrics quality , and metrics safety , in the lean operations of a system of stroke care are each factors that contribute towards a standardized stroke interventional laboratory with quality assurance and continued improvement in optimal stroke care. Adoption of such a system will identify value-added services, wasteful services and time delays, and identify missed opportunities for further improvements.

The SVIN Writing committee endorses appropriate training standards and enforcing existing requirements as well as monitoring total volume of each facility and operator [ 43 , 45 , 47 ]. Quality metrics, time-based metrics and task forces, as well as direct oversight by stroke interventional physicians are essential to improve outcomes. Lastly, stroke intervention provides a unique treatment to the community with dire unmet needs.

The SILC criteria further address the importance of ultra-early delivery of care within the first 60 min from the onset of symptoms, termed as the golden hour of stroke. European countries including Germany, UK, Spain, and Netherlands have succeeded in decreasing presentation times first medical contact to door as well as implementing key management steps of stroke code in the field en route to a facility. By uniformly organizing prehospital, ED, and stroke interventional laboratory management into a single supply chain, the stroke community will surely succeed in providing every stroke patient in the country with timely, appropriate treatments.

Vallabh Janardhan is a board member of Insera Therapeutics Inc. National Center for Biotechnology Information , U. Journal List Interv Neurol v. Published online Feb This article has been corrected. Abstract Brain attack care is rapidly evolving with cutting-edge stroke interventions similar to the growth of heart attack care with cardiac interventions in the last two decades.

Acute ischemic stroke, Large vessel occlusion, Endovascular therapy, Stroke intervention, Quality standards. Open in a separate window. Current stroke services recognized nationally within the stroke systems of care. Tiered Health Systems and Prehospital Triaging for Time-Sensitive Diseases To best prepare for a new national standard of stroke care and provide optimal, timely stroke interventions for AIS patients, the current collective sentiment among stroke interventionalists reflects a strong call for universal standardization across all stroke interventional laboratories.

Proposed Future Tiered System for EMS Triage of Stroke The future success of Brain Attack Care with stroke intervention and intra-arterial therapy lies in a lean supply chain method of operations that identifies efficiencies value added operations and wastes non-value added operations fig.


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  • Introduction!

Temporary embolizing agents like gelfoam are advantageous in that all traumatic lesions eventually heal and the vessel may not need to be permanently sacrificed. Angiogram A shows an abnormal vascular blush arrow from the branches of the superior mesenteric artery. Superselective catheterization and angiogram B of the culprit vessel confirms the finding of an active bleed arrow. Post-embolization image C shows no evidence of the active bleed. The management of vascular malformations depends on their type. In AVMs, the aim of endovascular treatment is to embolize and destroy the nidus.

Palliative therapy is performed with gelfoam soaked in absolute alcohol or a combination of glue and particles. Capillary hemangiomas usually involute spontaneously and conservative management may be initially attempted. Preoperative embolization may aid in surgical resection. Infants with high-output cardiac failure benefit from embolization therapy. Gelfoam pledgets, PVA particles or acrylic adhesives may be used. For AVFs, stent grafts, detachable balloons and multiple coils may be used. Venous angiomas are large blood-filled venous sacs, which may or may not be symptomatic.

Patients often seek therapy for cosmetic purposes. The treatment involves injection of absolute alcohol in the venous sac under anesthesia. The alcohol is limited to 0. Embolization is useful for many hypervascular neoplasms like chemodactomas, soft tissue sarcomas, hemangioblastomas, hemagiopericytomas, renal cell carcinomas and juvenile nasal angiofibromas. The aim of tumor embolization is to administer therapy that either aids in subsequent surgical resection or to provide primary tumor control as an alternative to surgery.

For certain tumors, it may be combined with the local delivery of chemotherapeutic agents in which case it is known as chemoembolization. Interventional vascular radiology has emerged as a first-line therapy in the management of PVD. Early detection followed by endovascular treatment forms the basis of treatment of PVD. Interventional procedures whenever feasible are effective and significantly reduce morbidity with reduced hospital stay and in most situations are more cost-effective than surgery. Although several new forms of treatment are coming into vogue, their routine use needs to be substantiated with further research.

We wish to thank Angela Chandrasena for her valuable inputs and for proofreading the manuscript. National Center for Biotechnology Information , U. Indian J Radiol Imaging. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Peripheral vascular diseases PVD are referred to as diseases affecting the blood vessels other than the heart and the brain. Angioplasty, embolization, interventional radiology, PVD.

Vascular & Interventional Radiology

Techniques for Revascularization Occlusive disease in the blood vessels of the lower limbs classically presents with features of ischemia, which in the early stages manifests as pain during exertion of the affected limb claudication. Percutaneous transluminal angioplasty and stenting PTA is performed predominantly with balloon catheters.

Open in a separate window. Endovascular therapy of carotid disease [ Figure 2 ]. Figure 2 A, B. Endovascular treatment of renal artery stenosis [ Figure 3 ]. Figure 3 A, B. Endovascular treatment of lower limb occlusive disease At present, the primary indication for intervention in lower limb arterial disease is a patient who has symptomatic arterial disease not adequately managed medically.

Femoropopliteal disease [ Figure 4 ]: Figure 4 A, B. Infrapopliteal disease [ Figure 5 ]: Figure 5 A, B. Complications of angioplasty Complications[ 18 ] include puncture site complications such as bleeding, pseudoaneurysm and arteriovenous fistula. Intra-arterial thrombolysis and mechanical thrombectomy Traditionally, balloon embolectomy has been the treatment of choice for patients with an acute arterial embolism.

Vascular radiation therapy Radiation therapy can be divided into external and intravascular temporary source or a permanent source. Gene therapy Therapeutic angiogenesis postulates the manipulation of a spontaneous healing response by supplementation of growth factors like vascular endothelial growth factor-VEGF or transplantation of vascular progenitor cells.

Techniques for revascularization in nonatherosclerotic occlusions Fibromuscular dysplasia FMD is an arteriopathy of unknown origin. Figure 6 A, B. Techniques Resulting in Vascular Occlusion Embolization is defined as the deliberate occlusion of vessels for a therapeutic response. Tumor embolization Embolization is useful for many hypervascular neoplasms like chemodactomas, soft tissue sarcomas, hemangioblastomas, hemagiopericytomas, renal cell carcinomas and juvenile nasal angiofibromas. Summary Interventional vascular radiology has emerged as a first-line therapy in the management of PVD.

Acknowledgments We wish to thank Angela Chandrasena for her valuable inputs and for proofreading the manuscript. Footnotes Source of Support: Nil Conflict of Interest: Interventional Radiology Today-What would charles dotter say? J Vasc Interv Radiol. Six- and twelve-month results from a randomized, double-blind trial on a slow-release paclitaxel-eluting stent for de novo coronary lesions. A randomized comparison of a sirolimus-eluting stent with a standard stent for coronary revascularization.

N Engl J Med. Interventional cardiac catheterization at Duke Medical Center. Initial and 6-month results of biodegradable poly-L-lactic acid coronary stents in humans. Randomized study of carotid angioplasty and stenting versus carotid endarterectomy: A neurovascular intervention to prevent stroke. Stenting in the carotid artery: Initial experience in patients.