Interventional Radiology Consultation in the ED: Beyond Correlate Clinically
- Jul 13th, 2020
- Thomas N. Jauch
Authors: Thomas N. Jauch, MD (EM Resident Physician, Emory University Department of Emergency Medicine/Grady Memorial Hospital) and Amy J. Zeidan, MD (EM Attending Physician, Emory University Department of Emergency Medicine/Grady Memorial Hospital, @amyjwal) // Reviewed by: Courtney Cassella, MD (@corablacas); Alex Koyfman, MD (@EMHighAK); and Brit Long, MD (@long_brit)
With recent advancements in imaging modalities and endovascular techniques, interventional radiology (IR) has become an increasingly popular and often less invasive option for treatment of a number of common medical emergencies. Here we summarize a few scenarios where a consult to IR may improve comprehensive care in the emergency department.
Interventional Radiology Applications: Trauma
Case: A 23-year-old male with no significant past medical history presents after a high speed roll over motor vehicle accident. The patient has a Glasgow Coma Score of 15 and vitals are significant for heart rate of 100 and blood pressure of 110/80. He reports a headache and abdominal pain with a notable seatbelt sign across his abdomen and chest.
The management of abdominopelvic trauma has advanced over the past century to favor nonoperative management strategies in patients who are otherwise hemodynamically stable. The standard of care for individuals who are unstable and/or have peritonitis remains urgent/emergent laparotomy. However, nonoperative strategies including angiography and embolization have emerged as important options in hemodynamically stable patients. Arterial embolization is effective in the management of hemorrhage from solid organ injuries and pelvic fractures.
The liver is one of the most commonly injured solid organs as a result of traumatic injury. Studies have demonstrated success, both in terms of mortality and morbidity, in nonoperative management of hemodynamically stable patients with grade III-IV hepatic injuries. According to the Eastern Association for the Surgery of Trauma (EAST) practice management guidelines, angiography with embolization is a level 2 recommendation for patients who transiently respond to resuscitation. Specifically, transarterial embolization (TAE) may be indicated in patients with active extravasation demonstrated on CT imaging or clinical signs of hemorrhage.1
A meta-analysis by Melloul et al investigated management of patients with grade III-V hepatic injury. TAE was used in only 3% of cases but had an embolization success rate of 93%.3 Similarly, a systematic review by Virdis et al evaluating outcomes of TAE in grade III-V hepatic trauma indicated a high primary arterial embolization success rate ranging from 80-97% for hemodynamically stable patients with contrast extravasation on CT. Common complications of TAE include liver necrosis, gallbladder ischemia or necrosis, abscess, or liver failure. Some studies have demonstrated success of another important indication of TAE, TAE after emergent laparotomy secondary to ongoing hemorrhage.
While additional studies are needed to confirm which patients benefit most from TAE, evidence indicates TAE is beneficial for hemodynamically stable patients with grade III-IV hepatic injuries but notable for a relatively high rate of postprocedural complications.,, It is important to reiterate, patients who are unstable or have peritonitis should undergo urgent laparotomy (EAST Level 1 recommendation). However, TAE is crucial in the nonoperative management or as an adjunct in hepatic injury due to trauma in hemodynamically stable patients.1
While not discussed in detail here, it should be noted other vascular interventional techniques outside of trauma have shown benefits in hepatic disease including portal vein embolization, transjugular intrahepatic portosystemic stent shunt (TIPSS) insertion, tumor embolization, hepatic artery infusion with chemotherapeutic agents, and hepatic venous intervention in Budd-Chiari syndrome (BCS).
Similar to the liver, the spleen is one of the most commonly injured solid organs as a result of trauma, and management strategies increasingly favor nonoperative approaches in hemodynamically stable patients. Level 2 EAST guidelines suggest angiography should be considered for “American Association for the Surgery of Trauma (AAST) grade of greater than grade III injuries, presence of a contrast blush, moderate hemoperitoneum, or evidence of ongoing splenic bleeding.” Additionally, level 3 recommendations suggest use of angiography as an adjunct to nonoperative management in patients with risk of delayed bleeding and as an investigative tool for identification of vascular abnormalities. Some studies evaluating angioembolization have shown success in preserving splenic function (splenic salvage) and controlling hemorrhage., A retrospective review by Haan et al indicated a 90% salvage rate with embolization, specifically an 80% salvage rate of grade 4 and 5 injuries. Notably, the salvage rates were less successful as grade of injury increased. Another study comparing operative and TAE management did not show a difference in splenic salvage rate. Complications of splenic embolization include major complications (splenic infarction, splenic abscess, contrast-induced insufficiency, splenic cyst) and minor complications (pleural effusion, coil migration, fever), with major complications as high as 13.6% in one study, and minor complications at 34.1%.
While there is still debate on the advantages of splenic embolization, high success rates have been reported following EAST level 2 guidelines in the nonoperative management of hemodynamically stable patients.
The kidneys are commonly injured from blunt and penetrating trauma. While not covered in depth here, angioembolization has demonstrated success, specifically in renal stab wounds. Level 3 EAST guidelines suggest use of angioembolization in nonoperative management. Further research is needed to differentiate the type of patients and injuries that would benefit most from this technique.
Patients with traumatic pelvic fractures resulting in hemorrhagic shock have a high mortality rate, reaching 50% in those with open pelvic fractures. While venous hemorrhage is more common (~85%) arising from the iliolumbar vein or bone fracture edges, arterial hemorrhage is more likely to lead to hemorrhagic shock. Angioembolization has a 74 – 100% success rate in controlling hemorrhage in patients with hemorrhagic shock secondary to pelvic trauma. According to EAST guidelines, angiography may be useful in controlling arterial hemorrhage in patients with pelvic fractures who are hemodynamically unstable without any other source of bleeding (Level I). Specific indications include patients with evidence of arterial intravenous contrast extravasation (Level I), patients greater than 60 years old with major pelvic fractures (open book, butterfly segment, or vertical shear) regardless of hemodynamic status (Level II), and patients with pelvic fractures who have ongoing bleeding after initial angiography. One study suggests a hematoma > 500 mL may be associated with arterial injury necessitating angiography. Angioembolization most commonly occurs for the following vessels: internal iliac artery, branches of the internal iliac, superior gluteal artery, obturator artery, and internal pudendal artery.21 Depending on the injury complex, bilateral embolization of the internal iliac artery may be required. The most common complications of angioembolization include wound breakdown/infection, gluteal muscle necrosis, and nerve injury. Finally, time to angioembolization is an important consideration with survival directly correlated to time. Ideally, patients should undergo angioembolization within 3 hours of arrival and sooner if possible.
Case Summary: After the primary and secondary surveys were completed, the patient was taken to CT. He was found to have a grade III splenic laceration with signs of active extravasation and left sided rib fractures. He underwent angioembolization and was admitted to the Surgical ICU. He was monitored closely post-procedurally. His vitals and hemoglobin remained stable. He was discharged home four days later and was doing well at his follow up visit one month later.
Interventional Radiology Applications: Pulmonary Embolism
Case: A 65 year-old female with a history of pancreatic cancer who recently underwent a Whipple procedure 1 week prior, presents with two days of pleuritic chest pain and shortness of breath. Vital signs are significant for a heart rate of 115 and a blood pressure of 86/50. The patient is in obvious distress with increased work of breathing.
Despite increases in diagnostic modalities and clinical awareness, pulmonary embolism (PE) remains a common cause of morbidity and mortality. In patients without contraindications, the mainstay of treatment for PE is anticoagulation. A subset of patients may benefit from thrombolytic therapy plus anticoagulation however systemic thrombolysis is associated with an increased risk of bleeding. Additionally, many patients are ineligible for thrombolytic therapy due to underlying comorbidities or recent invasive procedures. Catheter-directed therapy (CDT) is one option available for treatment in patients with contraindications to systemic thrombolysis or failure to improve with traditional therapy. As technology progresses, new devices and modalities for CDT are emerging at a rapid rate. Available modalities include mechanical clot fragmentation (the breakdown of clot into smaller pieces), thrombus aspiration (direct removal of the clot), local delivery of thrombolytics or a combination of each. Jaber & McDaniel describe the most commonly used techniques in detail. In thrombus maceration, a pigtail loop is manually rotated over a guidewire to dislodge the clot to more downstream vessels, with the goal of improving forward blood flow. Another method for clot fragmentation involves high-speed retrograde saline jets that create a vacuum, which can be combined with administration of local thrombolytics. Thrombectomy can be achieved by a number of devices, most often with some variation of a suction catheter. However, certain devices utilize advanced techniques including expanding discs, rotating screws, or a centrifugal pump.30
CDT offers several diagnostic and therapeutic advantages over systemic thrombolytics. Mechanical fragmentation and suction embolectomy improve hemodynamics by reducing clot burden, improving forward blood flow and subsequently venous preload.29 With mechanical fragmentation and local delivery of thrombolytics, therapy is directly targeted to the fragmented and then exposed clot resulting in a lower dosing of thrombolytics. Further benefit is incurred with the prompt administration of CDT compared to systemic thrombolytics which are routinely delivered over a period of two hours. Finally, response to CDT can be monitored in real time with angiography, allowing for continuous evaluation of pulmonary artery pressures and cardiac output.
Patient selection is critical when considering candidates for CDT. Currently, CDT is most widely accepted for the management of massive PE, given the high mortality rate. Massive PE is deﬁned as acute PE with hemodynamic changes, including sustained hypotension (systolic blood pressure <90mm Hg for a minimum of 15 minutes), or requiring inotropic support.27 Current guidelines from the American Heart Association (AHA) state that CDT is reasonable for patients with massive PE who have contraindications to fibrinolysis or remain unstable after receiving fibrinolysis (Class IIa; Level of Evidence C). They further state it is reasonable to consider transfer of a patient who has failed systemic fibrinolysis to a facility with CDT capabilities.
Submassive PE is defined as acute PE with evidence of right heart strain or myocardial necrosis. The utility of CDT in submassive PE is not yet well defined. Current AHA guidelines recommend CDT in submassive PE only if the patient has “clinical evidence of adverse prognosis,” including new hemodynamic instability, worsening respiratory failure, severe RV dysfunction, or major myocardial necrosis (Class IIb; Level of Evidence C). At this time, CDT is not recommended for patients with low risk PE or submassive PE with only minor RV dysfunction.
While CDT is an important therapy for patients with massive PE, specific treatment modalities are highly institution dependent and may be performed by a variety of specialists including but not limited to interventional radiologists, interventional pulmonologists, and interventional cardiologists.
Case Summary: Bedside echocardiography demonstrated right ventricular enlargement with flattening of the ventricular septum. The patient was taken for CDT with interventional cardiology where angiography confirmed the diagnosis of massive PE. She received mechanical clot fragmentation and local delivery of tissue plasminogen activator (tPA) with rapid improvement in hemodynamics. She was transferred to the cardiac care unit where she had an uneventful post-operative period and was ultimately discharged home on rivaroxaban 10 days later.
Interventional Radiology Applications: Stroke
Thrombectomy for Large Vessel Occlusion
Case: A 75 year-old man with a history of hypertension and diabetes presents with new onset right sided hemiparesis with arm weakness greater than leg. On your evaluation he is noted to have right sided facial droop with severe aphasia. The patient’s family last saw him in his usual health 8 hours prior.
The incidence of hemorrhagic and ischemic stroke has increased at an alarming rate. A 2013 study by Krishnamurthi et al found the incidence of new strokes was 16.9 million per year worldwide, with new cases of ischemic and hemorrhagic strokes increasing by 37% and 47% respectively from 1990-2010. The number of deaths attributed to stroke also increased by approximately 20%. In recent years, several clinical trials have demonstrated the efficacy of endovascular thrombectomy (EVT) for large vessel occlusion (LVO) and it is now considered the standard of care for select patients. Early studies such as the MR CLEAN trial demonstrated an absolute difference of 13.5 percentage points (95% CI, 5.9 to 21.2) in the rate of functional independence in favor of mechanical thrombectomy when compared to standard treatment when patients were treated within 6 hours of their last known normal time (LKN). In 2018, the DAWN trial demonstrated a significant benefit with use of thrombectomy in patients presenting between 6 and 24 hours of LKN. Specifically, this trial enrolled patients who had a severe clinical neurologic deficit (Group A: ≥ 80 years old, NIHSS ≥ 10, infarct volume <21mL; Group B: < 80 years old, NIHSS ≥ 10, infarct volume < 31mL; Group C: < 80 years old, NIHSS ≥ 20, infarct volume 31mL to less than 51mL) that was disproportionate to the volume of infarcted tissue on diffusion-weighted magnetic resonance imaging (MRI) or perfusion CT. By using advanced imaging, they identified patients with a small infarct (core) and large volume of salvageable, at risk tissue (penumbra). They demonstrated 90-day functional independence in 49% of the treatment arm versus 13% of the control arm. Considering recent trials, the American Heart Association (AHA) and American Stroke Association released updated guidelines for endovascular thrombectomy in stroke management in 2018 which are summarized by Ganesh and Goyal 2018 as follows36:
- Patients eligible for IV alteplase should receive IV alteplase even if EVT is under consideration.
- In patients under consideration for mechanical thrombectomy, observation after IV alteplase to assess for clinical response should not be performed (proceed directly to thrombectomy).
- Patients should receive mechanical thrombectomy with a stent retriever if they meet all the following criteria:
Further recommendations include obtaining perfusion imaging (CT or MR) or MRI with diffusion-weighted imaging in patients presenting >6 hours from LKN if these patients would have been eligible for thrombectomy under the DAWN or DEFUSE-3 trials. Of note, eligibility for DEFUSE 3 included patients presenting within 6-16 hours from LKN (including wake up strokes), initial infarct volume <70 ml, a ratio of volume of ischemic tissue to initial infarct volume of 1.8 or more, and an absolute volume of potentially reversible ischemia of 15 ml or greater.
Multiple scoring systems and clinical decision tools have been developed with the goal of identifying patients with LVO earlier on in the treatment course. One such scale known as the vision, aphasia, and neglect (VAN) screening tool demonstrated 100% sensitivity and 90% specificity in identifying patients with LVO. To be considered positive, patients must have arm weakness, including mild drift (while holding both arms in the air for 10 seconds) plus one of the following: vision deficit, aphasia, or neglect. The VAN screening tool performed better than an NIHSS score >6 in identifying patients with LVO. Combined with its ease of use for pre-hospital or triage providers, the authors suggest that implementation of this scoring system may help to identify patients with LVO sooner, leading to earlier intervention and better outcomes.
It is important to recognize that many medical centers do not have thrombectomy capabilities. At this time, there is insufficient data to make recommendations on pre-hospital triage of patients with LVO. The 2018 AHA/ASA guidelines state: “It remains unknown whether it would be beneficial for emergency medical services to bypass a closer IV tPA-capable hospital for a thrombectomy-capable hospital. While such an approach may delay IV tPA administration for patients who are and who are not mechanical thrombectomy candidates, this approach would expedite thrombectomy for those who are mechanical thrombectomy candidates.”39
Case Summary: The patient underwent non-contrast head CT, CT angiogram and CT Perfusion imaging which revealed no intracranial hemorrhage, an occlusive thrombus in the left M1-middle cerebral artery and a small area of core infarct with large penumbra, respectively. The patient was taken for mechanical thrombectomy and admitted to the Neurological ICU. By hospital day 3, the patient had complete resolution of his aphasia, facial droop with only mild residual arm weakness at time of discharge.
Interventional Radiology Applications: Lower Gastrointestinal Bleeding
Case: A 79-year-old man with a history of atrial fibrillation on rivaroxaban and recently diagnosed colon cancer presents with sudden onset bright red blood per rectum. On arrival he is tachycardic with a blood pressure of 98/60. His extremities are cool and active hemorrhage is noted on rectal examination.
Although endoscopy remains the primary diagnostic and therapeutic modality for treatment of gastrointestinal bleeding (GIB) there is an increasing role for interventional radiology, particularly in patients with refractory bleeding.Unprepared bowel or brisk bleeding may limit endoscopic visualization during colonoscopy, preventing localization of bleeding and therapeutic intervention. In these cases, angiography via CT, nuclear scintigraphy, or endovascular angiography may enable clinicians to identify the source of bleeding. Like endoscopy, endovascular angiography is both a diagnostic and therapeutic intervention and remains an effective alternative for lower GIB that is refractory to medical or surgical intervention.40 Of note, oral contrast agents should be avoided in patients who will undergo angiographic intervention as this can limit the diagnostic ability. Endovascular access is obtained through the common femoral artery and when a bleeding vessel is identified, arterial embolization is achieved with coils or polyvinyl alcohol particles. Complications include bowel ischemia, non-target embolization, arterial injury including dissection, pseudoaneurysm, and vasospasm. In a retrospective study by Rosetti and colleagues which included 23 patients who underwent selective colonic embolization, bleeding was successfully controlled in nearly 96%. However, 1 patient had a recurrent bleed with hemorrhagic shock, 16.7% required emergent surgical intervention due to bowel ischemia and 1 patient ultimately died. Approximately 90% of GIB is effectively treated with endoscopic intervention. However, endovascular techniques should be considered as a second line option, particularly in patients with hemodynamic instability, poor endoscopic visualization, or refractory bleeding.
Case Summary: The patient was resuscitated with 2 units of packed red blood cells and received 50 units/kg of prothrombin complex concentrates. His vital signs normalized but he continued to have hematochezia. An emergent CT angiography revealed active extravasation from a branch of the superior mesenteric artery secondary to local erosion from his colonic malignancy. After discussion with gastroenterology, colonoscopy was deferred given the high likelihood of poor visualization due to ongoing bleeding. Interventional radiology confirmed active extravasation from the ileocolic artery on angiography and hemostasis was achieved with coiling. The patient was ultimately discharged on hospital day 5 with outpatient oncology follow up.
Other Interventional Radiology Procedures
With the rapid evolution of interventional radiology techniques, there will likely be more involvement of interventional radiology specialists in emergency care. While not as common in ED settings, additional interventional techniques to consider for consultation include declotting and maintenance of AV fistulae, percutaneous nephrostomy placement for urinary tract obstruction, and percutaneous techniques for acute biliary disease. Fluoroscopically guided lumbar puncture is sometimes required for patients in which bedside lumbar puncture is unsuccessful. While indications and contraindications are relatively the same, important considerations include radiation exposure for women who are pregnant and contrast allergy if even a small amount of contrast will be used. Uncommon but special considerations include endovascular embolization in refractory epistaxis,, bronchial artery embolization for massive hemoptysis, uterine artery embolization for postpartum hemorrhage, embolization for spontaneous retroperitoneal hemorrhage in patients receiving anticoagulation, and endovascular treatment for type B dissections and descending aortic aneurysms.
Transarterial embolization is a valuable nonoperative management strategy for hepatic and splenic injuries in patients who are otherwise hemodynamically stable. It should be considered in patients where active extravasation is seen on CT imaging in the setting of grade III-IV hepatic injuries and/or grade III or greater splenic injuries. Patients should be monitored closely for post procedural complications. Angioembolization should also be considered for patients with pelvic trauma and evidence of active hemorrhage without any other source of bleeding.
CDT is an emerging treatment modality for hemodynamically unstable patients presenting with PE. CDT is not recommended for patients with low risk PE at this time. CDT is a beneficial treatment option in patients presenting with massive PE who have contraindications to or have failed treatment with systemic thrombolysis. CDT can be considered in patients with submassive PE who demonstrate new hemodynamic instability, worsening respiratory failure, severe RV dysfunction, or major myocardial necrosis. Consider early involvement of specialists capable of CDT at your institution. Although not discussed here, many hospitals are implementing PE response teams which can include members from interventional cardiology, interventional pulmonology, and/or interventional radiology to better expedite care in patients presenting with PE.
Thrombectomy for Large Vessel Occlusion
Multiple clinical trials have demonstrated efficacy and safety of thrombectomy for patients presenting with stroke from a large vessel occlusion. Thrombectomy should be considered in patients > age 18, with pre-stroke modified Rankin scale of 0-1, occlusion in the internal carotid artery or M1 segment, NIHSS ≥6, ASPECTS of ≥6, when treatment can be initiated within 6 hours of symptom onset. Certain patient populations may benefit from thrombectomy up to 24 hours from symptom onset but should be discussed with neurology consultants on a case by case basis. Consider implementing the VAN score to identify patients with LVO early on in their treatment course.
Lower Gastrointestinal Bleeding
Endovascular angiography in the diagnosis and treatment of lower gastrointestinal bleeding is an important alternative for patients with hemodynamic instability, poor endoscopic visualization, or refractory bleeding.
As mentioned previously, capabilities and guidelines vary by institution. For all of the above interventions, it is important to discuss with your institution’s interventional radiology department for specific options and indications.
 Stassen NA, Bhullar I, Cheng JD, et al. Nonoperative management of blunt hepatic injury: An eastern association for the surgery of trauma practice management guideline. Journal of Trauma and Acute Care Surgery. 2012;73(5 SUPPL.4).
 Friedman JA, Wilczynski TJD, Maheshwari N, Bianco BA. CT Imaging and Interventional Radiology in Solid Organ Injury. J Am Osteopath Coll Radiol. 2019;8(3):5-12.
 Melloul E, Denys A, Demartines N. Management of severe blunt hepatic injury in the era of computed tomography and transarterial embolization: A systematic review and critical appraisal of the literature. Journal of Trauma and Acute Care Surgery. 2015;79(3):468-474
 Virdis F, Reccia I, Di Saverio S, et al. Clinical outcomes of primary arterial embolization in severe hepatic trauma: A systematic review. Diagnostic and Interventional Imaging. 2019;100(2):65-75.
 Xu H, Jie L, Kejian S, et al. Selective angiographic embolization of blunt hepatic trauma reduces failure rate of nonoperative therapy and incidence of post-traumatic complications. Medical Science Monitor. 2017;23:5522-5533.
 Ierardi AM, Duka E, Lucchina N, et al. The role of interventional radiology in abdominopelvic trauma. British Journal of Radiology. 2016;89(1061).
 Misselbeck TS, Teicher EJ, Cipolle MD, et al. Hepatic angioembolization in trauma patients: Indications and complications. Journal of Trauma – Injury, Infection and Critical Care. 2009;67(4):769-773.
 Wang YC, Fu CY, Chen YF, Hsieh CH, Wu SC, Yeh CC. Role of arterial embolization on blunt hepatic trauma patients with type i contrast extravasation. American Journal of Emergency Medicine. 2011;29(9):1147-1151.
 Pereira BMT. Non-Operative Management of Hepatic Trauma and the Interventional Radiology: An Update Review. Indian Journal of Surgery. 2013;75(5):339-345.
 Stassen NA, Bhullar I, Cheng JD, et al. Selective nonoperative management of blunt splenic injury: An eastern association for the surgery of trauma practice management guideline. Journal of Trauma and Acute Care Surgery. 2012;73.
 Liu PP, Lee WC, Cheng YF, et al. Use of Splenic Artery Embolization as an Adjunct to Nonsurgical Management of Blunt Splenic Injury. Journal of Trauma – Injury, Infection and Critical Care. 2004;56(4):768-772.
 Raikhlin A, Baerlocher MO, Asch MR, Myers A. Imaging and transcatheter arterial embolization for traumatic splenic injuries: Review of the literature. Canadian Journal of Surgery. 2008;51(6):464-472.
 Wei B, Hemmila MR, Arbabi S, et al. Hepatic angioembolization in trauma patients: Indications and complications. Journal of Trauma – Injury, Infection and Critical Care. 2016;51(3):769-773.
 Haan JM, Bochicchio G V., Kramer N, Scalea TM. Nonoperative management of blunt splenic injury: A 5-year experience. Journal of Trauma – Injury, Infection and Critical Care. 2005;58(3):492-498.
 Smith HE, Biffl WL, Majercik SD, Jednacz J, Lambiase R, Cioffi WG. Splenic artery embolization: Have we gone too far? Journal of Trauma – Injury, Infection and Critical Care. 2006;61(3):541-544.
 Ekeh AP, Khalaf S, Ilyas S, Kauffman S, Walusimbi M, McCarthy MC. Complications arising from splenic artery embolization: A review of an 11-year experience. American Journal of Surgery. 2013;205(3):250-254.
 Heyns CF and Van Vollenhoven P. Selective surgical management of renal stab wounds. Br J Urol. 1992;69(4):351-7.
 Hagiwara A, Sakaki S, Goto H, et al. The role of interventional radiology in the management of blunt renal injury: a practical protocol. Journal of Trauma. 2001;51(3):526-531.
 Dinkel HP, Danuser H, Triller J. Blunt renal trauma: Minimally invasive management with microcatheter embolization – Experience in nine patients. Radiology. 2002;223(3):723-730.
 Holevar A, Ebert J, Luchette F, et al. Practice Management Guidelines for the Management of Genitourinary Trauma. The EAST Practice Management Guidelines Working Group. 2004. Accessed at https://www.east.org/education/practice-management-guidelines/genitourinary-trauma-management-of on April 1, 2020.
 Vaidya R, Waldron J, Scott A, Nasr K. Angiography and Embolization in the Management of Bleeding Pelvic Fractures. Journal of the American Academy of Orthopaedic Surgeons. 2018;26(4):e68-e76.
 Cullinane DC, Schiller HJ, Zielinski MD, et al. Eastern association for the surgery of trauma practice management guidelines for hemorrhage in pelvic fracture-update and systematic review. Journal of Trauma – Injury, Infection and Critical Care. 2011;71(6):1850-1868.
 Blackmore CC, Cummings P, Jurkovich GJ, Linnau KF, Hoffer EK, Rivara FP. Predicting major hemorrhage in patients with pelvic fracture. Journal of Trauma – Injury, Infection and Critical Care. 2006;61(2):346-352.
 Fu CY, Hsieh CH, Wu SC, et al. Anterior-posterior compression pelvic fracture increases the probability of requirement of bilateral embolization. American Journal of Emergency Medicine. 2013;31(1):42-49.
 Salcedo ES, Brown IE, Corwin MT, Galante JM. Pelvic angioembolization in trauma – Indications and outcomes. International Journal of Surgery. 2016;33(Part B):231-236.
 Agolini, Stefano, Shah, Kamalesh, Jaffe, James, et al. Arterial Embolization Is a Rapid and Effective Technique for Controlling Pelvic Fracture Hemorrhage. J Trauma. 1997;43(3):395-399
 Bremer, W., Ray, C. E., & Shah, K. Y. Role of Interventional Radiologist in the Management of Acute Pulmonary Embolism. Seminars in Interventional Radiology. 2020;37(01), 062–073.
 Chatterjee S, Chakraborty A, Weinberg I, et al. Thrombolysis for pulmonary embolism and risk of all-cause mortality, major bleeding, and intracranial hemorrhage: a meta-analysis. JAMA 2014;311(23):2414–2421.
 Kuo WT, Gould MK, Louie JD, Rosenberg JK, Sze DY, Hofmann LV. Catheter-directed therapy for the treatment of massive pulmonary embolism: systematic review and meta-analysis of modern techniques. J Vasc Interv Radiol. 2009;20(11):1431–1440.
 Jaber, W., & Mcdaniel, M. Catheter-Based Embolectomy for Acute Pulmonary Embolism: Devices, Technical Considerations, Risks, and Benefits. Interventional Cardiology Clinics. 2018;7(1), 91-101.
 Jolly M, Phillips J. Pulmonary embolism: current role of catheter treatment options and operative thrombectomy. Surg Clin North Am. 2018;98(02):279–292.
 Jaff MR, McMurtry MS, Archer SL, et al; American Heart Association Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation; American Heart Association Council on Peripheral Vascular Disease; American Heart Association Council on Arteriosclerosis, Thrombosis and Vascular Biology. Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientiﬁc statement from the American Heart Association. Circulation 2011;123(16):1788–1830.
 Krishnamurthi, R. V., Feigin, V. L., Forouzanfar, M. H., Mensah, G. A., Connor, M., Bennett, D. A., Murray, C. Global and regional burden of first-ever ischaemic and haemorrhagic stroke during 1990–2010: findings from the Global Burden of Disease Study 2010. The Lancet Global Health. 2013;1(5).
 Ganesh A, Goyal M. Thrombectomy for Acute Ischemic Stroke: Recent Insights and Future Directions. Curr Neurol Neurosci Rep. 2018 Jul 23;18(9):59.
 Fransen, P.S., Beumer, D., Berkhemer, O.A. et al. MR CLEAN, a multicenter randomized clinical trial of endovascular treatment for acute ischemic stroke in the Netherlands: study protocol for a randomized controlled trial. Trials. 2014;15:343.
 Nogueira RG, Jadhav AP, Haussen DC, et al. Thrombectomy 6 to 24 Hours after Stroke with a Mismatch between Deficit and Infarct. N Engl J Med. 2018 Jan 4;378(1):11-21.
 Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke.2018 Mar;49(3):e46-e110.
 Albers GW, Marks MP, Kemp S, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med. 2018 Feb 22;378(8):708-718.
 Teleb MS, Ver Hage A, Carter J, et al Stroke vision, aphasia, neglect (VAN) assessment—a novel emergent large vessel occlusion screening tool: pilot study and comparison with current clinical severity indices Journal of NeuroInterventional Surgery. 2017;9:122-126.
 Ramaswamy RS, Choi HW, Mouser HC, et al. Role of interventional radiology in the management of acute gastrointestinal bleeding. World J Radiol. 2014;6(4):82‐92. doi:10.4329/wjr.v6.i4.82
 Rossetti, A., Buchs, N.C., Breguet, R. et al. Transarterial embolization in acute colonic bleeding: review of 11 years of experience and long-term results. Int J Colorectal Dis 28, 777–782 (2013). https://doi-org.proxy.library.emory.edu/10.1007/s00384-012-1621-5
 Takeuchi N, Emori M, Yoshitani M, Soneda J, Takada M, Nomura Y. Gastrointestinal Bleeding Successfully Treated Using Interventional Radiology. Gastroenterology Res. 2017;10(4):259‐267. doi:10.14740/gr851e
 Zaleski G. Declotting, maintenance, and avoiding procedural complications of native arteriovenous fistulae. Seminars in Interventional Radiology. 2004;21(2):83-93.
 Pabon-Ramos WM, Dariushnia SR, Walker TG, et al. Quality Improvement Guidelines for Percutaneous Nephrostomy. Journal of Vascular and Interventional Radiology. 2016;27(3):410-414.
 Saad WEA, Wallace MJ, Wojak JC, Kundu S, Cardella JF. Quality Improvement Guidelines for Percutaneous Transhepatic Cholangiography, Biliary Drainage, and Percutaneous Cholecystostomy. Journal of Vascular and Interventional Radiology. 2010;21(6):789-795.
 Özütemiz C, Rykken JB. Lumbar puncture under fluoroscopy guidance: a technical review for radiologists. Diagnostic and Interventional Radiology. 2019;25(2):144-156.
 Huyett P, Jankowitz BT, Wang EW, Snyderman CH. Endovascular Embolization in the Treatment of Epistaxis. Otolaryngology – Head and Neck Surgery (United States). 2019;160(5):822-828.
 Willems PWA, Farb RI, Agid R. Endovascular treatment of epistaxis. American Journal of Neuroradiology. 2009;30(9):1637-1645.
 Panda A, Bhalla AS, Goyal A. Bronchial artery embolization in hemoptysis: A systematic review. Diagnostic and Interventional Radiology. 2017;23(4):307-317.
 Chen C, Lee SM, Kim JW, Shin JH. Recent update of embolization of postpartum hemorrhage. Korean Journal of Radiology. 2018;19(4):585-596.
 Dohan A, Sapoval M, Chousterman BG, Primio M, Guerot E, Pellerin O. Spontaneous Soft-Tissue Hemorrhage in Anticoagulated Patients: Safety and Efficacy of Embolization. Am J of Roentgenology. 2015; 204(6):1303-1310.
 Fanelli F, Dake MD. Standard of practice for the endovascular treatment of thoracic aortic aneurysms and type B dissections. CardioVascular and Interventional Radiology. 2009;32(5):849-860.