CT Angiography Findings in Carotid Blowout Syndrome and Its Role as a Predictor of 1-Year Survival

BACKGROUND AND PURPOSE:Carotid blowout is a serious late complication of prior treatment of advanced head and neck cancer. We evaluate the efficacy of CTA in the diagnosis of impending carotid blowout syndrome in patients with head and neck cancer, and its capability to predict clinical outcome.MATERIALS AND METHODS:The clinical data of 29 patients with impending carotid blowout who underwent CTA were collected and analyzed. Imaging signs included tissue necrosis, exposed artery, viable perivascular tumor, pseudoaneurysm, and contrast extravasation. DSA was obtained in 20 patients. One-year outcomes were compared based on management.RESULTS:The most common CTA finding was necrosis (94%), followed by exposed artery (73%), viable tumor (67%), pseudoaneurysm (58%), and contrast extravasation (30%). Exposed artery, pseudoaneurysm, and contrast extravasation were the 3 CTA findings related to outcomes. All of the pseudoaneurysm and contrast extravasation cases were associated with an exposed artery. An exposed artery was the most important prognostic predictor and could not be diagnosed on DSA. Patients without the 3 findings on CTA (group 1) had the best survival rate at 1-year follow-up, followed by patients with the 3 findings treated immediately by permanent artery occlusion (group 2). Patients with the 3 findings who had no immediate treatment (group 3) had the worst outcomes (P < .001 in group 1 vs group 3 and group 2 vs group 3; P = .056 group 1 vs group 2).CONCLUSIONS:CTA, with its ability to diagnose an exposed artery compared with DSA, may offer important management and prognostic information in patients with impending carotid blowout.

Carotid blowout syndrome (CBS) is defined as rupture of the carotid artery and its branches and is a serious complication after treatment of advanced head and neck cancer. Potential causes of CBS include radical resection, radiation therapy and radiation necrosis, carotid exposure, wound infection, pharyngocutaneous fistula, and recurrent or persistent carcinoma.¹ The overall incidence of carotid blowout after neck dissection has been reported to be as high as 4.3%, and the risk is increased another 7.6-fold with further radiation therapy.² CBS typically occurs 2–20 years after surgery or radiation therapy,^3,4 and average estimates of cumulative neurologic morbidity and mortality are above 60% and 40%, respectively, in patients with CBS.⁵ CBS can be categorized into 1 of 3 categories: threatened, impending, and acute carotid blowout.¹ Threatened carotid blowout is defined as physical examination or imaging results that suggest inevitable hemorrhage from 1 of the carotid arteries or its branches if no action is taken. Impending carotid blowout (also called sentinel hemorrhage) is defined as transient hemorrhage that resolves spontaneously or with packing or pressure. Acute carotid blowout represents hemorrhage that cannot be controlled by packing or pressure.¹ Surgical management of carotid blowout is usually technically difficult and is associated with high morbidity and mortality rates.^1,2,6,7 After surgical ligation or permanent arterial occlusion (PAO) of the carotid artery, the incidence of immediate or delayed cerebral ischemic complications can be as high as 15%–20%.^7,8–12 The complication rate of a balloon occlusion test before PAO of the carotid artery is reported to be as high as 3.2%, and it may be even higher in fragile postirradiation vessels.¹³ Delayed ischemia after passing the balloon occlusion test is yet another concern.^10,14,15 Stent-graft deployment, with or without coiling, is another endovascular treatment of CBS. Stent-grafting can preserve the affected carotid flow but has a high rate of early and delayed complications.^16–19 No significant difference in short-term outcome between stent-graft deployment and PAO has been reported,²⁰ and long-term results have not been reported.¹⁷CTA has become widely available and is sensitive and specific in the detection of hemorrhagic vascular disorders such as aneurysms, arteriovenous malformations, dural arteriovenous fistulas, and intracranial dissections. Contrast extravasation on CTA predicts hematoma expansion, mortality, and clinical outcome in primary intracerebral hemorrhage.^21–26 To our knowledge, there have been no past reports about the use of CTA in the diagnosis of CBS or as an outcome predictor. The aim of our study was to evaluate the efficacy of CTA in the diagnosis of impending CBS, and its capability to predict clinical outcome after management.