CoA of the descending thoracic aorta generally presents in childhood. The aortic CoA in adult patients is extremely rare; only a few cases where it is the sole congenital malformation or where it is combined with other defects in the same patient have been reported.
Some authors have suggested single-stage procedure in reccurent CoA associated with intracardiac pathologies. [1–3] Vijayanagar et al. were the first to describe performing concomitant aortic valve replacement and the ascending aorta-descending aorta bypass through the posterior pericardium and placing the graft arround the left margin of the heart entirely through a sternotomy incision. Barron et al. have defined two different extra-anatomic bypass techniques.
Pethig et al. pointed out severe hemodynamic instability after relief of the aortic CoA with ascending-descending aorta bypass. They thought that the hypertrophied left ventricle had adapted to high perfusion pressures, relief of isthmic stenosis resulted in a major drop in the ascending aorta postoperatively and this blood pressure appears to be inadequate to maintain sufficient myocardial pressure in hypertrophied left venricules. The large conduit and peripheral vasodilatation may cause a rapid runoff and resultant coronary steal immediately after discontuning CPB circulation. For that reason, weaning from bypass should be under adrenalin and noradrenaline infusion in that kind of patients. Mulay et al. reported three patients, the intracardiac pathologic lesions were corrected first, and the CoA was repaired as a second-stage procedure 6 weeks later. They defined that the single-stage approach would have caused a sudden decrease in systemic vascular resistance during coming off bypass and that could be the reason of hemodynamic instability as Pethig mentioned in their article.
In our experience, the most crucial point was the afterload management during weaning from bypass. We believe that carefull adrenaline + noradrenaline infusion is enough to provide sufficient peripheral vascular resistance. The use of CPB also adds safety for patients with unstable hemodynamics. Operating on the cardiac defect without addressing the significant CoA may lead to significant hypoperfusion of organs distal to CoA and severe afterload increase may stress the left ventricle causing pump failure. [7, 8]
Any attempts at CoA repair in these patients would be disastrous without prior or simultaneous coronary revascularisation. The internal mammary arteries are often increased in size and are unsuitable for use as conduit for revascularization. In patients requiring coronary artery bypass grafting in combination with CoA repair, care must be taken to ensure adequate mammary artery flow before its use, because of its greater susceptibility for atherosclerotic narrowing. LIMA graft was used only in one patient that required CABG, in our two cases.
Fedoruk et. al. reported compression of esophagus causing dysphagia in a 9 year-old child due to the extra-anatomic bypass is lying on the right side of the heart. In this route, the graft length is at least 2 times longer than the left route. Additionally, the graft is passing from above or behind the inferior vena cavae and lying arround the right atrium which could have risk for compression of surrounding tissues but this statement is not declared clearly by the authors.
The mortality and morbidity of a staged surgical approach is significant, irrespective of the sequence of repair. Correction of the coarctation alone is associated with increased perioperative myocardial infarction. On the other hand, correction of the cardiac lesion alone is associated with increased postoperative renal failure and paraplegia as a result of inadequate perfusion distal organ perfusion. In adulthood, the dependency of the spinal cord blood supply on fewer radicular arteries increases the risk of paraplegia developing during the postoperative period. The technique of hypothermic CPB with HCA has several advantages when applied to adult patients with complex forms of CoA. It facilitates adequate exposure of the structures involved, avoids placement of clamps on fragile tissue, and provides adequate protection of the brain, the spinal cord, and other organs.
The main indications for single-stage repair are:
Calcified or serious adult CoA with concomitant cardiovascular pathologies required surgery.
CoA with serious triple coronary artery disease.
Re-CoA with concomitant cardiovascular pathologies required surgery.
For the treatment of CoA and associated with cardiac anomalies, we have utilized the use of ALSAB between the arcus aorta and the descending aorta without side-biting clamp under HCA which was never used or published before. Side-biting clamp using in the hypertansive patients and mostly atherosclerotic aorta has a risk of neurologic complications and also neighbour organ (esophagus) and collateral artery damage at the distal anastomotic side could be expected dispate the all reporters not noticed any that kind of problem so far. The limitation of using our technique is extensive calcification at the arcus aorta. Hypothermic CPB and HCA techniques lend a margin of a safety for spinal cord ischemia.[8, 12] We believe that the use of CPB is the best method and HCA provides a very dry field for surgeon to perform aortic anastomosis and also reduces the risk of paraplegia.
Our technique's superiority against the previous methods is single incision, short graft length and not using/no necessity side-biting clamp that could be the reason of neurologic disorder or neighbour organ damage such as esophagus. The use of HCA has some risks but it has provided easy exposure of the distal thoracic aorta and avoided the necessity of side-biting clamp. Even though some authors suggested different extra-anatomic routes for the bypass conduit, ALSAB technique might reduce the risk of kinking and long graft requirement. We conclude that single-stage repair of CoA and associated cardiovascular lesions can be performed safely and effectively using this technique without the risk of graft related problems.