Carotid Blowout Syndromes
Patients with head and neck bleeding secondary to compromise of the carotid artery can be rapidly assessed and managed endovascularly.
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Many patients with head and neck cancer undergo radical or partial neck dissection either during initial treatment or at the time of tumor recurrence. These patients may later present with oral, nasal, or peritracheal bleeding falling into one of two patterns: chronic intermittent bleeding or catastrophic hemorrhage, with or without a sentinel hemorrhagic event. ER management includes packing to temporarily stop bleeding and resuscitative measures including airway protection, IV fluids, and blood replacement.
Hemorrhagic complications can be rapidly assessed and treated using endovascular techniques. Careful and methodical diagnostic superselective angiography, microcatheter approaches to embolization, and selection of optimal embolic agents can result in durable hemostasis and the saving of lives.
Diagnostic imaging management varies with the two types of presentation. CT scan of the neck (with IV contrast if renal function permits) is useful in patients with either chronic intermittent bleeding or small sentinel hemorrhages. CT allows assessment of residual tumor burden and its relationship to the common, internal, and external carotid branches. CT angiography can often be accomplished at the same sitting with a single bolus of 100 cc to 120 cc of contrast and can demonstrate the contour and configuration of the major vessels.
Although small vessel sources of hemorrhage are difficult to define with cross-sectional imaging, pseudoaneurysms may be identified prior to angiography. Imaging may help localize a tumor in relation to hemorrhage when no extravasation is identified at angiography. In patients with life-threatening, catastrophic hemorrhage, acute resuscitation and rapid triage to angiography without cross-sectional imaging is appropriate and expeditious management.1-3
PATHOLOGY AND PATHOPHYSIOLOGY
Hemorrhage can result from four major causes: 1) tumoral hemorrhage secondary to tumoral neovascularity; 2) tumoral erosion or vascular laceration of an external carotid branch; 3) pseudoaneurysm formation secondary to tumoral erosion and/or radiation therapy; or 4) acute major vessel rupture secondary to pseudoaneurysm or tumor erosion. Chronic or intermittent hemorrhage is most commonly associated with tumoral neovascularity; the other three processes often present with more massive bleeding.1,2,4
DIAGNOSTIC ANGIOGRAPHIC PROTOCOL
Diagnostic angiographic protocols vary slightly with the nature and location of the hemorrhage. As in other areas of the vascular system, selectivity is the key to safe and successful endovascular therapy.1,2,4,5 These procedures are best performed with patients intubated for airway control, and ideally with anesthesia support. A central line is critical for resuscitation and can later allow Swan-Ganz catheter placement for monitoring following carotid sacrifice.
Bilateral imaging of the common carotids, the internal carotids, the external carotids, and the vertebral arteries will establish the bleeding site as well as the integrity of the Circle of Willis. This is important in patients who may require carotid artery sacrifice. Vertebral angiography can be omitted in patients with established integrity of the major vessels and in those with purely external carotid lesions or tumoral neovascularity.
Selective external carotid branch arteriography is often required to identify a bleeding site not demonstrable on more global injections. Internal maxillary, facial, lingual, ascending pharyngeal, and superior thyroid arteries are the vessels most commonly involved. In patients with peritracheal bleeding, the thyrocervical trunk must also be examined bilaterally.
BALLOON OCCLUSION TOLERANCE TESTING
Sacrifice of the involved carotid may be the only life-saving option when treating a patient with a lesion of the common or internal carotid (such as pseudoaneurysm, ulceration, or long segment irregularity).1,2,4,6,7 The use of covered stents may be an option in some patients, however, one must be prepared to convert a stent procedure into carotid occlusion if hemostasis cannot be maintained.8
Ideally, when time permits, a temporary balloon occlusion test (BOT) is performed to ascertain tolerance of carotid artery occlusion prior to the procedure. Three components include diagnostic arteriography for collateral assessment, clinical testing during temporary occlusion, and HMPAO-SPECT or Xenon CT evaluation of cerebral blood flow during temporary occlusion. BOT is performed with placement of a nondetachable balloon catheter into the internal or common carotid artery using a microballoon or a conventional 8.5-mm nondetachable occlusion balloon catheter.1,4,6,8 The patient is systemically heparinized and neurologic testing is ongoing during occlusion. Systemic hypotension is induced with reduction of mean arterial pressure to two-thirds of normal using a sodium nitroprusside infusion. During pressure reduction, the patient is injected with HMPAO for a first-pass assessment of cerebral blood flow.
Carotid blowout may manifest as uncontrollable hemorrhage. Carotid sacrifice must then be performed without clinical preocclusion testing in order to be lifesaving. In this situation, HMPAO-SPECT is performed following occlusion in order to assist in postocclusion hypertensive and hypervolemic management. The occlusion balloon is withdrawn and the carotid sacrificed using detachable balloons, complex helical or retrievable detachable coils, or a combination. Clinical management in the intensive care unit includes neurologic monitoring and hemodynamic measures to maintain cerebral perfusion pressure. Baseline CT scan of the head is useful following patient stabilization.
When carotid sacrifice cannot be safely performed due to lack of collateral flow or a lack of tolerance of temporary BOT, and stent placement is not an option, surgical extracranial to intracranial bypass techniques may be needed, in association with carotid sacrifice, to permit adequate cerebral blood flow. 9
OTHER SOURCES OF HEMORRHAGE
Oral, nasal, or peritracheal bleeding may result from tumoral neovascularity or erosion through the wall of a small external carotid branch vessel, rather than major vessel erosion. Selective external carotid branch arteriography is often required to demonstrate the bleeding site. Microcatheterization both permits identification of the bleeding site and allows for more selective placement of embolic material. Selection of embolic material depends upon the site and the nature of the hemorrhage source. Alcohol has no role in the treatment of hemorrhagic complications of head and neck malignancy.1,2,4,5,10
Hemorrhage derived from neovascularity of the tumor or local granulation tissue can be treated with medium-sized, 250-micron to 350-micron particles of polyvinyl alcohol foam (PVA) suspended in contrast media. We introduce the particles into the tumor under roadmap guidance using a microcatheter and 1-cc syringes until the neovascularity is sufficiently reduced. Proximal gelfoam pledgets may be adjunctive. One should avoid using small 50-micron to 150-micron particles if additional surgery is not planned, in order to avoid frank tumor necrosis.
Vascular Laceration or Pseudoaneurysm
Vascular laceration or pseudoaneurysm may be treated directly with microcatheter embolization to address the specific bleeding site. Embolic materials vary. Gelfoam with or without complex helical coils may be used for a discrete vessel laceration; we use Trufill n-BCA Liquid Embolic System (Cordis Corporation, a Johnson & Johnson company, Miami, FL), where possible, for pseudoaneurysm or focal extravasation (Figure 1). Proximal vessel coil embolization should be avoided, because it does not directly address the site of pathology. In the majority of cases, when attempts at proximal occlusion have failed to control hemorrhage, small microcatheters can navigate beyond proximally placed clips or coils for distal embolization. When choosing an embolic agent, pay attention to the site of the lesion, the nature of adjacent collaterals, the distal parenchymal territory, and the role of embolization (ie, presurgical or palliative).10,11,12
MAJOR VESSEL LESIONS
During the initial angiographic assessment, catheter placement should be proximal to the suspected carotid injury. Cross-sectional imaging is helpful when available; however, the location of surgical clips and brachytherapy seeds are indicators of potential vascular compromise.
For frank rupture, sacrifice of the carotid artery above and below the point of rupture will prevent the creation of a pattern of unreachable collateral flow. Detachable balloons are quick and effective embolic agents when the carotid can accept the 7F delivery catheter. High detachment-force balloons are suggested to decrease the chance of distal embolization. If vessel size is a limitation due to disease or radiation, microcatheter delivery of retrievable detachable and/or complex helical coils can be achieved using a 5F guiding catheter system that still permits contrast delivery around the microcatheter (Figure 2).
Treatment of pseudoaneurysm, ulceration, and segmental irregularity usually also requires carotid sacrifice for treatment of hemorrhage. When time permits and in the absence of extravasation, BOT with HMPAO-SPECT should be performed. Covered stent placement is experimental and may hold some promise for treatment of some of these lesions. Coiling of a pseudoaneurysm with or without stent assistance may result in vessel rupture. These are high-risk lesions and controlled carotid sacrifice is the most reliable, durable, and safest method of treatment today. Further research, the development of longer covered stents, and even presurgical, preradiation stent placement may hold future promise for management of these patients.13,14,15
Michele H. Johnson, MD, is the Director of Interventional Neuroradiology and Associate Professor of Radiology and Otolaryngology at Yale University School of Medicine in New Haven, Connecticut. Dr. Johnson may be reached at (203) 785-7214; firstname.lastname@example.org.
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