CrossBoss First is a single-blind randomized controlled trial that will randomize 246 patients undergoing clinically-indicated Chronic Total Occlusion Percutaneous Coronary Intervention, to upfront use of the CrossBoss catheter vs. antegrade guidewire escalation strategy The "CrossBoss First" study has two primary objectives. The primary efficacy objective is to compare the procedure time required to cross the CTO or abort the procedure with a CrossBoss first vs. antegrade wire escalation strategy. The investigators hypothesize that upfront use of the CrossBoss catheter will be associated with shorter procedure time required for CTO crossing compared with an antegrade wire escalation strategy.

The primary safety objective is to compare the frequency of procedural major adverse cardiovascular events (MACE) with upfront use of CrossBoss vs. a guidewire escalation strategy. The investigators hypothesize that upfront use of the CrossBoss catheter will be associated with similar incidence of MACE compared with an antegrade wire escalation strategy.

The secondary endpoints are: (1) technical and procedural success4-6; (2) total procedure time (defined as the interval between administration of local anesthesia for obtaining vascular access and removal of the last catheter); (3) fluoroscopy time to cross the CTO and total fluoroscopy time; (4) total air kerma radiation exposure; (5) total contrast volume; and (6) number of wires, microcatheters, balloons, and stents used.

Inclusion Criteria:

• Age 18 years or greater
• Willing and able to give informed consent
• Undergoing clinically-indicated CTO PCI with a planned antegrade crossing approach

Exclusion Criteria:

• Plan for primary retrograde approach for CTO crossing
• Ostial CTOs (within 5 mm of vessel ostium)