Functional assessment of intermediate lesions of collateral donor artery in chronic total coronary occlusions

Abstract

ABSTRACT Introduction and objectives: The strategy of the percutaneous treatment of patients with multivessel disease associated with chronic total coronary occlusion (CTO) lesions is not well defined. Also, the functional significance of lesions located in the collateral donor artery has not been fully addressed. Using the fractional flow reserve (FFR) the objective was to evaluate the amount of ischemia related to the angiographically intermediate stenosis of collateral donor vessels before and immediately after successful percutaneous coronary intervention (PCI) of a CTO. Also, to assess any changes operated in the amount of ischemia using cardiovascular magnetic resonance imaging prior to the PCI and at 1-month follow-up. Methods: Prospective pilot study including 14 patients with stable angina and a CTO receiving collateral circulation from a blood vessel with intermediate stenosis (50%-70% diameter stenosis measured using quantitative angiography). In order to indicate recanalization by PCI all patients were referred for magnetic resonance assessment of the presence of myocardial viability. Results: Seven (50%) of the 14 patients included showed FFR values ≤ 0.80 before the PCI. FFR measures of the donor artery significantly increased after the revascularization of the CTO (0.75 [0.73-0.78] vs 0.83 [0.81-0.84]; P = .017). Eventually, only 3 patients showed hemodynamically significant FFR values after the recanalization of CTO requiring further revascularization. There was a tendency towards a reduction of the number of ischemic segments (2.5 [0-4] vs 0 [0-0.25]; P = .066) assessed using magnetic resonance imaging before and after the PCI. No major adverse cardiovascular events were reported at the 2-year follow-up. Conclusions: Our data suggest that FFR measurements in intermediate stenoses of collateral donor vessels of a CTO may be misleading. Therefore, the strategy of focusing primarily on the revascularization of the CTO and then on the assessment of the intermediate lesion in a collateral donor vessel may be recommended.

Keywords

• Chronic total coronary occlusion
• Collateral donor vessel
• Fractional flow reserve
• Cardiovascular magnetic resonance imaging