Impact on Instantaneous Wave-Free Ratio (IFR) on a Mildly Diseased Native Epicardial Vessel Supplying Collateral to the Contralateral Vessel Chronic Total Occlusion (CTO)—A Case Depicting the Change Before and After CTO Intervention.
Presenter
Karthik Subramanian Anand, MD, Texas Cardiovascular Institute, Fort Worth, TX
Karthik Subramanian Anand, MD, Texas Cardiovascular Institute, Fort Worth, TX and Karim Al-Azizi, M.D., FSCAI, Baylor Scott & White Health, Frisco, TX
Title:
Impact on Instantaneous wave-Free Ratio (IFR) on a moderately diseased native epicardial vessel supplying collateral circulation to the contralateral vessel Chronic Total Occlusion (CTO)- A case depicting the change before and after CTO intervention.
Introduction:
Over the last two decades, multiple studies have been conducted to understand coronary flow hemodynamics. The introduction of fractional flow reserve (FFR) and Instantaneous wave-Free Ratio (IFR) have had huge impact in intervening moderately diseased native coronary arteries. CTO with collateral circulation from the contralateral coronary causes changes in blood flow affecting the FFR and IFR calculation in the native epicardial disease supplying the collaterals. The change in IFR values is more significant when there is moderate disease in the vessel being evaluated.
Clinical Case:
48-year-old male with prior Coronary Artery Disease, prior Percutaneous Intervention (PCI) of Left Anterior Descending artery (LAD) in 2009 has been complaining of anginal symptoms, worsening over the last 6 months. His functional status has declined significantly. He came for an elective left heart catheterization (LHC) and possible PCI. Diagnostic catheterization revealed CTO for proximal Right Coronary Artery (RCA), moderate disease of proximal LAD with 50% focal lesion and a 50% stenosis of mid Left circumflex artery (LCx) with Left to Right Collateral circulation. A decision to intervene the RCA CTO was made. Spot IFR done to LCx and LAD prior to CTO intervention was 0.95 and 0.82 respectively. Successful intervention of RCA CTO with antegrade wire escalation (Technique) and 3.5x34mm drug eluding stent (DES) was done. Post intervention angiographic images showed no collateral circulation and IFR of proximal LAD was 0.93.
Discussion:
IFR is an excellent method to evaluate moderate diseases of coronary arteries. Understanding the hemodynamics is important in interpreting the findings. Through this case report we emphasize that while evaluating coronary disease of vessels with collateral circulation, await until CTO intervention is completed and re-evaluate the non CTO vessel with IFR to obtain more accurate information.