Irradiation abolishes smooth muscle investment into vascular lesions in specific vascular beds.

The long-term adverse effects of radiotherapy on cardiovascular disease are well documented. However, the underlying mechanisms responsible for this increased risk are poorly understood. Previous studies using rigorous smooth muscle cell (SMC) lineage tracing have shown abundant SMC investment into atherosclerotic lesions, where SMCs contribute to the formation of a protective fibrous cap. Studies herein tested whether radiation impairs protective adaptive SMC responses during vascular disease. To do this, we exposed SMC lineage tracing (Myh11-ERT2Cre YFP+) mice to lethal radiation (1,200 cGy) followed by bone marrow transplantation prior to atherosclerosis development or vessel injury. Surprisingly, following irradiation, we observed a complete loss of SMC investment in 100% of brachiocephalic artery (BCA), carotid artery, and aortic arch lesions. Importantly, this was associated with a decrease in multiple indices of atherosclerotic lesion stability within the BCA. Interestingly, we observed anatomic heterogeneity, as SMCs accumulated normally into lesions of the aortic root and abdominal aorta, suggesting that SMC sensitivity to lethal irradiation occurs in blood vessels of neural crest origin. Taken together, these results reveal an undefined and unintended variable in previous studies using lethal irradiation and may help explain why patients exposed to radiation have increased risk for cardiovascular disease.

Endovascular management of radiotherapy-induced injury to brachiocephalic artery using covered stents.

Actinic vascular lesions tend to be stenotic-occlusive lesions. In this article, we present 2 exceptional cases of pseudoaneurysms caused by radionecrosis of the supra-aortic trunks. Both patients were treated by a retrograde carotid approach and deployment of a self-expanding covered stent. Proper exclusion of the pseudoaneurysm was attained in both cases; the first patient remained asymptomatic 12 months later; the second patient died of mediastinitis. Compared with conventional surgery, endovascular management is a viable, less invasive alternative in select patients, especially in life-threatening cases.

[Iatrogenic injury of the brachiocephalic arterial trunk and its branches--case report]. / Jatrogena ozljeda brahiocefalicnog arterijskog stabla i njegovih ogranaka: prikaz slucaja.

Iatrogenic vascular traumas are increasing and their proportion exceeds 40% of all vascular injuries. We report on a rare case of iatrogenic injury of the brachiocephalic arterial trunk during surgical intervention due to postirradiation arteriopathy, which was successfully treated with a silver prosthesis graft. A 58-year-old male underwent surgery for metastases of papillary carcinoma of the thyroid gland, located in lymph nodes adjacent to the right common carotid artery and right subclavian artery. During the surgery, there was an intraoperative injury of the brachiocephalic arterial trunk that included spontaneous rupture and tear of the subclavian and common carotid artery, as the result of extreme fragility of the arterial wall, probably due to the previous irradiation therapy. Emergency sternotomy and clavicle resection were followed by blood flow reconstruction by use of an Y prosthesis that was applied for terminoterminal anastomosis between the brachiocephalic trunk to common carotid artery and subclavian artery. The authors concluded that irradiation therapy may lead to progressive arteriopathy in affected arteries.

Tracheoinnominate artery fistula as a complication of radiation therapy.

Tracheoinnominate artery fistulization is a well-known complication of tracheostomy and of tracheal resection. The first known occurrence of this problem in a patient in whom no transtracheal procedure had ever been performed is reported, and high-dose radiation therapy delivered three years before for a mediastinal malignancy is suggested as the cause. No evidence of tumor was found in or adjacent to the tracheovascular communication. The tracheoinnominate artery fistula must be considered a potential complication of radiation therapy as well as of surgery.