Endovascular repair of thoracic and abdominal aortic diseases as an alternative to open surgery in patients at high surgical risk

Sep 5 2006

World Congress of Cardiology Report - Acute aortic syndromes, such as large thoracic and abdominal aortic aneurysms with impending rupture, complicated acute type B dissections, traumatic rupture of thoracic aorta, still represent life-threatening conditions.

Different therapies are available, but controversy persists as to which is the most effective. Optimal timing for management remains debated as well. Surgical therapy is contraindicated in many cases because of advanced age and/or the presence of severe comorbidities such as pulmonary disease, renal dysfunction, cerebrovascular disease, coronary artery disease, congestive heart failure.

EVAR for aortic pathologies offers several advantages compared to conventional open surgery: limited invasiveness, lower morbidity, less hemodynamic and metabolic stress in the absence of need for aortic clamping and declamping, shorter hospitalization stay. There has been great progress in endovascular treatment since the early days with modified endografts and new devices designed to correct previously encountered problems (TALENTTM, Medtronic Inc). The aim of our study was to evaluate the safety and efficacy of EVAR over a 4-year period. From March 2001 till June 2005, 157 patients underwent EVAR: 101 (64.3%) with abdominal aortic aneurysm (AAA), 51 patients (32.4%) with thoracic aortic diseases, and 5 patients (3.2%) with a combined thoraco-abdominal aneurysm. A comorbid medical illness (ASA class III- IV) was observed in 109 pts (69.4%).The thoracic group consisted of 7 pts (13.7%) with traumatic aortic rupture, 18 patients (35.3%) with a thoracic aortic aneurysm (TAA), and 26 patients (51%) with a type B dissection. In AAA group 19/101 patients (18.8%), unfit for open surgery, showed a challenging anatomy because of a severe (>60°) proximal aortic neck angulation.

The stent graft placement was performed in a dedicated catheterization laboratory using a high performance X-ray equipment that allows for optimal angiographic visualization. High definition fluoroscopy is required for manipulations that require detailed imaging such as precise and controlled device deployment. The dedicated cath-lab can be converted into a surgical theatre in case of need for conventional surgery. The procedures are performed by an experienced interventional cardiologist with the support of a cardiovascular surgeon and two dedicated nurses. Patients receive general anaesthesia and mechanical ventilation during thoracic endovascular procedures and epidural anaesthesia during abdominal endovascular procedures. All procedures are performed under controlled hypotension induced by infusion of sodium nitroprusside (target mean arterial pressure of approximately 60 mmHg) just before the placement of the endograft. The vascular access is commonly transfemoral and the implantation of the endoprosthesis is achieved through a surgical exposure and arteriotomy of common femoral arteries.

Early results showed no perioperative death, no paraplegia and no open surgical conversion. The average length of intensive care unit and hospital stay was 1.7 ± 0.9 and 6.9 ± 3.0 days, respectively.

The intraoperative angiography and CT-scan on discharge showed no significant endoleaks (contrast visualization in the aneurysmatic sac) in any patient. At 4-year follow-up, there were 3 late deaths (one procedure-related) in the thoracic group and 9 (none procedure-related) in AAA group. A traumatic patient with a type I endoleak was successfully treated by a secondary EVAR 16 months after the first procedure.

Our data show that EVAR in high surgical risk patients with acute aortic syndromes is an effective and low-risk treatment strategy.

Patients with aortic diseases are often elderly and they have severe comorbidities, making them poor surgical candidates. Although direct comparison may not be justified because of differences in patient selection and the relatively small number in our series, in-hospital and mid-term results seem to be very encouraging. In the combined experience from EUROSTAR and UK THORACIC ENDOGRAFT registries, the reported in-hospital mortality for emergency repair was 29% in aortic thoracic aneurysms, 12% in acute type B dissections, 6% in traumatic ruptures. In our experience, we treated high-risk patients in emergency conditions without in-hospital mortality and with only 3 late deaths in patients in whom the surgical risk was considered prohibitive. In our abdominal series, 40% of patients were older than 75 years and younger patients had at least two concomitant diseases. All patients with AAA who underwent endovascular treatment in our study were at high-risk for conventional open surgical repair on the basis of number and nature of their comorbid medical conditions. Not surprisingly, midterm outcome was affected by known concomitant diseases in this population.

Although long-term data are not yet available, EVAR represents a lower risk approach, associated with a shorter operating time, shorter hospitalization stay, a more rapid recovery time and improved quality of life during the perioperative period and midterm follow up.