2.3 Surgical procedure
The operations were performed by the same surgeon. Both groups of
patients underwent MIAVR via an upper sternum approach. Briefly, an
upper hemisternotomy to the right side was performed in the midline and
the third or fourth intercostal space guided by the preoperative chest
computer tomography
(CT), forming a J-shape incision.
The distal ascending aorta was cannulated. Multi-stage venous
cannulation (Medtronic, Minneapolis, MN) was performed through the
femoral vein. The ascending aorta was cross-clamped and crystalloid was
perfused antegrade through the aortic root soon after initiating CPB,
while letting the nasopharyngeal temperature drip to 32-34°C. If the
patient has combined aortic valve insufficiency, the crystalloid was
perfused through the coronary artery sinus after the ascending aorta was
incised. A transverse incision was made 1 cm above the sinotubular
junction, and 3 traction sutures were drawn on the upper and lower edges
of the incision to expose the aortic valve. In the FLS group, scissor
was used to cut off as many diseased leaflets as possible, and a nerve
hook was used to incise a gap at the base of the calcified nodule to
loosen the connective tissue of the spongiosa layer, then the fibrosa
layer at the calcified tissue could be completely peeled off easily
(Fig. 1 and the Supplementary Video S1). This method ensures complete
removal of the calcified tissue on the valve stump and the annulus. In
the conventional group, calcified tissue on the valve stump and annulus
was mechanically crushed by rongeur forceps, before the calcified debris
was carefully removed. Once the diseased valve was excised and annulus
debrided, a Carpentier-Edwards Perimount Magna aortic pericardial valve
(Edwards Lifesciences, Irvine, CA) was implanted with continuous or
interrupted suturing. The traction sutures were removed and the
aortotomy was closed. Once the patient was weaned from CPB,
transesophageal echocardiography was employed to assess
effective orifice area
(EOA), mean gradient, correct
positioning of the prosthesis and possible
paravalvular leak
(PVL). A single mediastinal drainage
tube was placed into the anterior mediastinum before the closure of
chest.