5. Rationale for antegrade preparation first

For the vast majority of CTO, antegrade wiring should be done first. The new generation of wires offer excellent wire control and can often cross even long CTOs quickly, therefore a brief antegrade attempt should be considered in the vast majority of CTOs. Performing antegrade preparation first before starting retrograde also reduces the amount of time the retrograde system is engaged in the donor artery and therefore reduces the risk of donor artery thrombosis/ischemia. Antegrade preparation also allows the operator to go straight to reverse CART once retrograde wire overlaps with the antegrade wire. Since reverse CART is a much faster method to get wire crossing compared to retrograde wiring, the procedure will be shortened by going straight to reverse CART. Also, going directly to reverse CART can prevent the complications of retrograde wiring including, the risk of retrograde wire causing hematoma in normal vessel proximal to the CTO or in the case of ostial LAD CTO, wiring subintimally into the left main and out into the aorta. The consequence of retrograde wiring into subintimal left main and out of the aorta are horrific as after stenting there will be circumflex artery occlusion.

In conclusion, the rationale for antegrade preparation first are
1. Antegrade wiring is often successful,
2. It reduces donor artery risk by reducing retrograde system engagement time,
3. It encourages direct reverse CART which reduces procedure time, and
4. It prevents the risks associated with single retrograde wire crossing.