Chronic Total Occlusion Revascularization Retrograde Approach
Chronic Total Occlusion Revascularization Retrograde Approach
Registry data demonstrate that 15–30% of patients undergoing diagnostic coronary angiography will have at least one occluded coronary artery. Prevalence data are more variable, mainly owing to differing definitions of what constitutes a CTO lesion and limitations of the study's design. The Canadian CTO registry reported a prevalence of 18.4% in patients with significant CAD undergoing nonurgent coronary angiography, while a retrospective review of >6500 patients reported CTO lesions in up to 52% of patients. However, the true prevalence is probably unknown owing to the proportion of patients who have little or no symptoms.
Patients are referred for CTO revascularization for a variety of reasons. Most commonly, typical symptoms of stable exertional angina or a positive noninvasive test prompt coronary angiography. Alternatively, a coincidental nonculprit CTO lesion is found during treatment for an acute coronary syndrome. Indeed, new presentations with acute coronary syndrome are rarely directly attributable to CTO lesions, although many patients with CTO lesions will have evidence of previous myocardial infarction (MI).
The treatment options available to patients with documented CTOs include medical therapy alone or in combination with PCI or coronary artery bypass graft (CABG). CABG has historically been the preferred revascularization option owing to its higher immediate procedural success rate in the CTO vessel. In addition, many CTO patients have multivessel disease and will more frequently require target vessel revascularization (TVR) after PCI. The Canadian CTO registry data demonstrate that out of 1697 patients, only 10% had attempted CTO PCI. In total, 20% had PCI performed in non-CTO arteries, 44% were treated with medical therapy and 26% underwent CABG. Other factors that may have contributed to the low referral rate for CTO PCI include physician skepticism over the benefits of CTO PCI and financial disincentives for the hospital. With respect to the durability of successful CTO PCI the advent of drug-eluting stents has significantly reduced the risk of restenosis and need for repeat revascularization. TVR rates for CTO PCI are now comparable to those for other 'off-label' drug-eluting stent procedures. Although the rate of TVR following CTO PCI may reach as high as 16%, it is also important to recognize that in a randomized trial of 400 patients assessing 1-year patency after bypass grafting of collateralized CTO vessels only 23% of non-left anterior descending artery CTO grafts remained patent. However, the surgical results of grafting left anterior descending artery CTOs were much better with 100% patency at 12 months.
Prevalence & Current Management
Registry data demonstrate that 15–30% of patients undergoing diagnostic coronary angiography will have at least one occluded coronary artery. Prevalence data are more variable, mainly owing to differing definitions of what constitutes a CTO lesion and limitations of the study's design. The Canadian CTO registry reported a prevalence of 18.4% in patients with significant CAD undergoing nonurgent coronary angiography, while a retrospective review of >6500 patients reported CTO lesions in up to 52% of patients. However, the true prevalence is probably unknown owing to the proportion of patients who have little or no symptoms.
Patients are referred for CTO revascularization for a variety of reasons. Most commonly, typical symptoms of stable exertional angina or a positive noninvasive test prompt coronary angiography. Alternatively, a coincidental nonculprit CTO lesion is found during treatment for an acute coronary syndrome. Indeed, new presentations with acute coronary syndrome are rarely directly attributable to CTO lesions, although many patients with CTO lesions will have evidence of previous myocardial infarction (MI).
The treatment options available to patients with documented CTOs include medical therapy alone or in combination with PCI or coronary artery bypass graft (CABG). CABG has historically been the preferred revascularization option owing to its higher immediate procedural success rate in the CTO vessel. In addition, many CTO patients have multivessel disease and will more frequently require target vessel revascularization (TVR) after PCI. The Canadian CTO registry data demonstrate that out of 1697 patients, only 10% had attempted CTO PCI. In total, 20% had PCI performed in non-CTO arteries, 44% were treated with medical therapy and 26% underwent CABG. Other factors that may have contributed to the low referral rate for CTO PCI include physician skepticism over the benefits of CTO PCI and financial disincentives for the hospital. With respect to the durability of successful CTO PCI the advent of drug-eluting stents has significantly reduced the risk of restenosis and need for repeat revascularization. TVR rates for CTO PCI are now comparable to those for other 'off-label' drug-eluting stent procedures. Although the rate of TVR following CTO PCI may reach as high as 16%, it is also important to recognize that in a randomized trial of 400 patients assessing 1-year patency after bypass grafting of collateralized CTO vessels only 23% of non-left anterior descending artery CTO grafts remained patent. However, the surgical results of grafting left anterior descending artery CTOs were much better with 100% patency at 12 months.
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