Re: Double arterial perfusion strategy for extensive thoracic aortic surgery to avoid lower body hypothermic circulatory arrest

Abstract

Czerny and his co-workers report a technique of double arterial perfusion to avoid lower body hypothermic circulatory arrest in 10 patients undergoing extensive thoracic aortic repairs [1]. A median sternotomy combined with a left fourth intercostal space incision was utilized to provide exposure of the entire thoracic aorta. There was no hospital mortality, 2 patients (20%) sustained a stroke, and one each developed acute renal failure and myocardial infarction. Their technique represents another modification of the onestage approach to treat extensive thoracic aortic aneurysmal disease, some of which develops after previous procedures on the thoracic aorta such as repair of acute type A dissection. The authors employed a double arterial perfusion strategy and double-clamping of the descending thoracic aorta to avoid lower body hypothermic circulatory arrest, and selectively perfused the brachiocephalic vessels with a separate roller pump at a temperature of 20°C. This was stated to be a potential advantage over techniques that employ hypothermic perfusion of the lower body with intervals of ischaemia [2, 3]. Although lower body ischaemia is presumably avoided with their technique, acute renal failure developed in 1 patient and no information regarding hepatic or intestinal function was provided. With procedures that involve replacement of most or all of the descending thoracic aorta, the risk of spinal cord ischaemia increases, and some degree of hypothermia may be advantageous. As an example, performance of the distal anastomosis of the graft to the aorta at or near the aortic hiatus in the diaphragm would preclude distal aortic clamping. None of the patients in the present series had a replacement of more than two-thirds of the descending thoracic aorta. No major pulmonary complications were reported, and the authors attribute this to minimal manipulation of the left lung, since it was limited only to the area of the distal anastomosis of the graft to the descending thoracic aorta. In the setting of chronic aortic dissection however, control of bleeding from patent intercostal arteries is mandatory and sometimes troublesome, and can require exposure of the entire opened descending thoracic aorta and greater manipulation of the left lung. Despite these minor criticisms, the authors are to be commended for pursuing the strategy of a one-stage approach for the treatment of extensive thoracic aortic disease. Given the limitations of the two-stage and hybrid techniques for the treatment of extensive thoracic aortic disease, particularly in patients with chronic aortic dissection, we strongly support the authors’ recommendation that continued evaluation and refinement of techniques that involve a one-stage approach are indicated [4–6].