Antegrade Wire Escalation: The Foundation of Chronic Total Occlusion Percutaneous Coronary Intervention

Goal

Select the equipment most likely to assist with CTO crossing.

How?

A microcatheter or over-the-wire balloon should be used for antegrade crossing in all CTOs (i.e., CTO crossing should not be attempted with unsupported guidewires) because such a system:

• a.

  Enhances the wire penetrating capacity ( Figure 2.17 ).

• b.

  Allows wire tip reshaping without losing wire position.

• c.

  Facilitates wire exchanges.

• d.

  Prevents twisting of wires when using the parallel wire technique.

A microcatheter is preferred by most operators (as described in Chapter 2 , Section 2.4 ), because it:

• a.

  Allows accurate assessment of the microcatheter tip location (because the marker is located at the tip, whereas in 1.20–1.50 mm balloons the marker is located in midshaft and the tip is not angiographically visible).

• b.

  Is more resistant to kinking.

These advantages are particularly important in cases of tortuosity or poor guide catheter support , because over-the-wire balloons:

• a.

  Are prone to kinking upon wire removal, thus hindering reliable wire exchanges.

• b.

  Provide less support due to lack of wire braiding.

• c.

  Are more likely to cause proximal vessel injury.

Goal

Deliver a guidewire and microcatheter/over-the-wire balloon to the proximal CTO cap.

How?

Unless the CTO proximal cap is ostial or very proximal, it should be accessed with a workhorse guidewire advanced through a microcatheter, over-the-wire balloon, or the CrossBoss catheter .

CTO wires with high penetrating power and tapered tips should not be used to traverse the proximal vessel to get to the CTO proximal cap because:

• a.

  They can cause vessel injury, especially in diffusely diseased vessels ( Fig. 4.1 ).

• b.

  The wire bend required to reach the CTO is usually different (much larger) than the wire bend used when entering and crossing the CTO (much smaller) ( Fig. 4.2 ).

A soft-tipped, workhorse guidewire should be used to reach the CTO proximal cap, followed by the microcatheter or over-the-wire balloon ( Fig. 4.3 ). The guidewire is then switched for the CTO crossing guidewire through the microcatheter or over-the-wire balloon ( Fig. 4.4 ).

After removing the workhorse guidewire, contrast injection through the microcatheter can sometimes be very useful for clarifying the location and characteristics of the proximal cap.

Goal

Select the most appropriate guidewire for initial antegrade CTO crossing.

How?

Although several coronary guidewires are available for CTO crossing, a simplified selection and escalation scheme is preferred ( Fig. 4.5 ).

A detailed description of the guidewires and their properties is presented in Chapter 2 , Section 2.5 . A tapered, polymer-jacketed wire (such as the Fielder XT, Fielder XT-A or Fighter) is usually used first to track a microchannel (which may sometimes be invisible). This attempt should be brief, unless progress is achieved.

If this wire fails to cross, and the course of the CTO vessel is well understood (especially if the CTO is short), a stiff, tapered guidewire (such as the Gaia 2nd) is preferred. If the course of the CTO is unclear, then a stiff, polymer-jacketed guidewire (such as the Pilot 200) or a composite core, moderate stiffness, nontapered guidewire (such as the Ultimate Bros 3) is preferred, because it is more likely to track the vessel architecture than exit the vessel wall.