Common procedures of MI induction in three groups

The three groups all went through the following six procedures including anesthesia, percutaneous femoral artery puncture, selective coronary angiography (CAG), conventional ischemic preconditioning and prevention of arrhythmia, balloon occlusion or embolization, and postoperative monitoring and treatment.

Briefly, animals were anesthetized with ketamine (20 mg/kg, IM) and introduced intravenous catheters in marginal ear veins. Continuous infusion of propofol (0.003 ml/kg/min) was administrated to maintain anesthesia. Animals were continuously monitored and inhaled oxygen (3 L/min). The right or left femoral artery was identified, and a 6-Fr radial arterial introducer sheath (Terumo, Japan) was advanced over the guidewire in the femoral artery by percutaneous puncture. When it was necessary, ultrasound could be used to assist the puncture. Heparin sodium was given as a 150 IU/kg bolus IV at the start of the procedure and continued at 50 IU/kg/h IV throughout the operation. Femoral artery angiography was performed (Fig. 1), and a 6-Fr guiding catheter (Judkins right 4.0 type) was advanced into the ostium of the coronary artery. Baseline selective coronary angiography and left ventricular angiography were performed, and the target blocking location was determined. Lidocaine (0.03 mg/kg/min) was intravenously infused throughout the following procedures. In case of VF, nonsynchronized direct current defibrillation was performed at 360 J. Along with the guidewire, the 1.5–2.5-mm balloon catheter according to target vessel diameter was inflated and deflated three times in the mid-LAD as the ischemic preconditioning [23, 24]. Each time, the balloon was inflated 6–8 atm for 5 mins with the interval of 1 min. Subsequently, all animals were performed mid-LAD balloon occlusion or embolism procedure according to grouping. Finally, the arterial sheath was removed, followed by 30 mins oppression on the femoral artery puncture area. After the procedures, all the animals received antibiotics (penicillin 640 WU once a day, for 3 days).

Minipig femoral artery angiography in three groups. a, b Display arterial introducer sheath in the right and left femoral artery, respectively. c–e The angiography of right and left femoral artery and iliac artery, internal iliac artery, and abdominal aorta, respectively. The yellow arrows indicate the location of introducer sheath, and the red arrows indicate the location of skin puncture