Chronic Total Occlusions

Pathophysiology

Pathogenesis of coronary artery disease which can progress to CTO lesions, has multiple contributing factors, which include upregulation of the immunologic and inflammatory markers (cytokines, leukocytes, high sensitivity C-reactive protein), endothelial dysfunction, and cholesterol accumulation. Most commonly, it starts with the collection of smooth muscle cells within the intima, and this progresses to macrophages accumulating in the intima leading to pathologic intimal thickening and progression of lesions.

CTO PCI Procedure

• Most patients with a symptomatic total coronary occlusion traditionally required coronary artery bypass graft (CABG) surgery to treat the blockage.
• Total blockages of the coronary artery have historically been among the most challenging lesions to treat with interventional procedures.
• New technology and advanced percutaneous techniques now allow experienced physicians to significantly improve success rates, making PCI a viable treatment option for symptomatic patients.
• Calcification within a chronic total occlusion (CTO) is an independent predictor of PCI failure, prolonged procedure duration, suboptimal stent expansion, and complications.
• CTO can be crossed by luminal tracking (intraplaque) or by dissecting around the occlusion through the less resistant subintimal space (extraplaque).
• These approaches can be performed antegradely using antegrade wiring (AW) or antegrade dissection re-entry (ADR).
• Retrograde techniques include retrograde wiring (RW) or retrograde dissection re-entry (RDR).
• Calcium modification is often required, especially when the course is intraplaque.
• Plaque calcium morphology may be concentric, eccentric, or nodular, while extraplaque tracking can create a calcified pseudonodule.
• Calcium modification during CTO PCI is frequently performed using scoring balloons (SB), cutting balloons (CB), high-pressure (OPN) balloons, rotational atherectomy (RA), orbital atherectomy, or laser atherectomy.

During the Procedure

• At the start of the procedure, patients receive sedation.
• During the procedure, two catheters are placed in arteries through the leg or wrist to allow forward or backward access as needed.
• Cardiac interventionists use specialized guide wires and catheters that are carefully steered across total blockages.
• The fine movement of the guide wire tip is easier to control compared to previous guide wire designs.
• At select centers in the United States, including the Cleveland Clinic, physicians may use a retrograde approach in which total coronary blockages are accessed through collateral blood vessels.
• Collateral blood vessels are newly formed vessels that reroute blood flow around a blockage and develop as blockage severity increases.
• During the procedure, the patient may be awakened and encouraged to speak with the doctor if any discomfort occurs.
• The procedure generally takes approximately 3 to 4 hours.
• First-time success rates are approximately 85% to 90%.
• In some cases, partial success occurs and patients may be advised to undergo a repeat attempt after 6 to 8 weeks.
• Most patients are discharged the following day after evaluation of catheter insertion sites and blood test results.

Results

• Patients who undergo CTO PCI often experience improvement in symptoms within days to weeks.
• Some patients notice improvement even before discharge.
• Studies have shown that patients who undergo CTO PCI may experience improvements in quality of life, including:
  • Reduced chest pain (angina)
  • Reduced shortness of breath
  • Increase in physical activity
  • Decrease in feelings of depression
  • Higher energy levels
• The Mass General CTO PCI team will arrange post-procedure follow-up care.