Carotid artery revascularization through a radiated field

Abstract

Objective

Extracranial carotid stenosis is a complication of external head and neck irradiation. The safety and durability of carotid artery revascularization through a radiated field has been debated. We describe the immediate and long-term results in a series of 27 consecutive patients who received treatment over 12 years.

Methods

From May 1990 to May 2002, 27 consecutive patients underwent 30 primary carotid artery revascularization procedures. All patients had received previous radiation therapy within a mean interval of 10 years (range, 1-26 years), with average radiation dose of 62 Gy (range, 50-70 Gy). Moderate to severe scarring of the skin or radiation fibrosis was present in three fourths of patients. Thirteen patients (48%) had undergone radical neck dissection, and 2 patients had a permanent tracheotomy. The indications for carotid surgery included high-grade (>70%) symptomatic stenosis in 18 patients (60%) and high-grade asymptomatic stenosis in 12 patients (40%). General anesthesia with systematic shunting was used in 18 patients (60%), and regional anesthesia with selective shunting was used in 12 patients (40%). Operations included standard carotid endarterectomy (n = 20), with patch angioplasty (n = 12) or direct closure (n = 8); carotid interposition bypass grafting (n = 7); and subclavian to carotid bypass grafting (n = 3). Primary closure of the surgical wound was performed in all procedures without any special muscular or skin flaps. All patients were followed up for a mean of 40 months (range, 3-99 months).

Results

There was one (3.3%) perioperative death, from massive intracerebral hemorrhage; and 1 patient had a transient ischemic attack. In-hospital complications included neck hematoma in 2 patients, which required surgical drainage in 1 patient. There was neither delayed wound healing nor infection. Twelve patients died during follow-up, of causes not related to treatment. None of the surviving patients had further stroke, and all remained asymptomatic. Follow-up duplex scans showed asymptomatic recurrent stenosis greater than 60% in 3 patients, 2 of whom with stenosis greater than 80% underwent repeat operation. Risk for recurrent stenosis greater than 60% at 18 months was 16.6%. Recurrent stenosis occurred in 2 of these patients after saphenous vein bypass, and in 1 patient after endarterectomy with vein patch angioplasty.

Conclusion

The clinical results and sustained freedom from symptoms and stroke over 40-month follow-up suggests that carotid revascularization through a radiated field is a safe and durable procedure in patients at high surgical risk, despite a marked incidence of recurrent stenosis.

Radiation-induced accelerated atherosclerosis has been recognized for some time.1, 2, 3 and 4 Because of the prolonged survival of patients treated with radiation,5 the frequency of this long-term side effect is expected to increase. In a prospective study, late (>70%) carotid artery stenosis was found in 11.7% of 240 patients who had undergone cervical irradiation.6 The chronic effects of radiation therapy lead to decreased vascularity and increased fibrosis, which in turn lead to risk for tissue necrosis, infection, and ulceration. In addition, many stenoses involve extensive segments of the carotid artery and other supra-aortic vessels, which renders surgical management more demanding.7 and 8 No prospective randomized study exists to guide optimal therapy in patients with radiation-induced accelerated high-grade carotid stenosis who do not fit eligibility criteria set forth in the major clinical trials.9 and 10 Furthermore, the potential additional morbidity incurred from treatment in patients who have undergone radiation therapy may invalidate the documented benefit of surgical carotid revascularization. Thus, to elucidate factors important in the management of these cases and to assess safety and durability of the procedure, we reviewed our experience over 12 years.