Procedure
The patient’s body was tilted to the left, and the right side of the back was slightly elevated. TTE was used to determine the position of the trans intercostal incision based on the location of VSD and the main direction of blood flow. A surgical incision ≤ 1 cm in length (the minimum incision in this study was 0.7 cm) was made at the left margin of sternum of the 3rd to the 5th intercostal spaces, normally the 4th intercostal space (Fig.2B, Fig.2C).
The subcutaneous soft tissues were opened by blunt dissection without entering into the pleural cavity. The pericardium was transversely incised and hung with 4-5 sutures (Fig.2A). TEE was used to determine the position of the purse-string suture on the right ventricular surface. With the real-time guidance of TEE, the cardiac surgeon moved the tweezers in order for the tweezers’ head to point toward the PmVSD and the main direction of blood flow. An optimal angle from the selected site toward the VSD facilitated the guidewire passing through the VSD.
After heparin (1mg/kg) was administered, a purse-string suture was made at the position of the tweezers’ head under direct visualization. TEE was placed at a suitable angle for real-time monitoring and guidance. A punch needle was inserted into the right ventricle through the pouch. Then, the guidewire was sent to the left ventricle through the PmVSD (Fig. 3b). The delivery sheath and the dilator were introduced to the left ventricle over the guidewire after the puncture needle was withdrawn. If the defect diameter of VSD was too small , surgeon should expand VSD using the bigger dilator so that the delivery sheath pass through the PmVSD smoothly. While the top of the sheath was confirmed to be in the left ventricle, the guidewire and the dilator were withdrawn (Fig. 3C. The short loading sheath was then connected to the long delivery sheath. The occluder was pushed to released the left disk from the sheath (Fig. 3D). According to the shape of PmVSD and AMS, the left disk was placed on the left ventricular side of PmVSD or pulled all or partly into the aneurysm. Then, the delivery sheath was withdrawn back to the right ventricle, and the waist of the device and the right disk were fully released (Fig. 3E).
TEE was immediately performed. If the device were perfectly released without complications such as device dislocation, residual shunt, device-related valve regurgitation (especially the tricuspid valve) and arrhythmia, the device was inspected repeatedly by a push-pull maneuver and unscrewed from the delivery cable. Otherwise, the occluder was adjusted, withdrawn, or replaced if complications arose.
After the occluder was released and unscrewed from the delivery cable, the protective device suture contributed to the retrieval of the device through a larger delivery sheath if the device was found to be displaced by TEE . If all went well, the suture was gently pulled out from the device and the delivery device was withdrawn. The last steps were to ligate the purse-string suture and close the incision in layers (Fig. 3).
ECG monitor was used to monitor heart rhythm and blood pressure during the operation. During the surgery, care should be taken in monitoring heart rhythm, blood pressure, oxygen saturation, blood gas analysis and airway management. If these indications are abnormal, the procedure should be discontinued and should even be cancelled.