3|DISCUSSION
For adults suffering from symptomatic AS, SAVR is recommended in those at low risk (EuroSCORE II<4%), while the TAVI is considered to be a choice for patients who are not suitable for SAVR, especially for those suitable for transfemoral access2. Another traditional therapy for symptomatic AS is balloon aortic valvotomy, which usually be chosen for hemodynamically unstable patients in the transitional period to SAVR or TAVI2.
However, a significant number of patients with symptomatic AS are not referred to the three above-mentioned traditional methods for some complexity conditions. Risk factors among them include severely calcified aorta root or ascending aorta (porcelain aorta) and/or aortic valve leaflet, narrow left ventricular outflow tract (<18 mm)1, small aortic annulus, ascending aorta banding, severe left ventricular dysfunction, previous CABG3. AVB is regarded as a good option for reducing the left ventricular overload by connecting the left ventricular apex and descending aorta in patients with contraindications to SAVR and TAVI.
We presented a case of AVB surgery that was conducted successfully in a high-risk symptomatic AS patient with contraindications to methods. Internal diameters of the aortic annulus, aortic sinus and ascending aorta are narrow with severe calcification to the extent that it is hard to inflate a balloon or release a transcatheter aortic valve. Besides, there was a lack of appropriate valve in the market we can found. Considering of the coarctated and porcelain aorta, replacement of ascending aorta combined SAVR seemed necessary, but the mortality risk calculated by EuroSCORE II for this operative plan was 72.04%. In this case, patient characteristics showed contraindications to SAVR, TAVI and balloon aortic valvotomy. To widen the total area of the left ventricular tract and decrease the cardiac afterload, we finally performed a surgical procedure of aortic valve bypass and aortic valvuloplasty in consideration of the severe stenosis and moderate regurgitation of the aortic valve.
Indication for AVB is severe symptomatic AS in high-risk patients with contraindications to both AVR and TAVI1. The implantation of the apico-aortic conduit relieves left ventricular outflow obstruction by shunting blood flow. Compared with TAVI, Patients undergoing AVB procedures have similar in-hospital mortality, lower complication rate, and fewer hospital charges3. Even so, AVB is seldom offered as the initially routine treatment as a result of the technical difficulty of apical anastomosis procedure. The new invention of an automated apical connector device would help collapse the technical barriers4.
A theoretical risk of the AVB procedure is the possibility of flow subtraction with cerebral hypoperfusion ascribed to the competition between the antegrade and retrograde flow from two ventricular outputs. In a recent study, Benevento et al.5 showed that the blood flow distribution after AVB depends on the effective orifice area of the stenotic aortic valve and apico-aortic valved conduit implanted. Mantini et al.6 reported that the flow redistribution after AVB does not compromise cerebral blood supply. Another serious complication is aortic thrombosis at the level of flow stagnation caused by the collision of two blood flows, which is more likely to happen when the retrograde flow is dominant and antegrade/retrograde flows are equivalent7. The recommendation is that patients who underwent AVB receive long-term strict anticoagulation7.