DOI: 10.1161/circ.148.suppl_1.14679 ISSN: 0009-7322

Abstract 14679: Microcirculatory Flow and Resistance at Rest and Hyperemia in Relation to Major Adverse Cardiovascular Events in Chronic Coronary Syndrome

Shajan Shekarestan, Fadi Jokhaji, Christina Ekenback, Mattias Törnerud, Samantha Lorstad, Petter Ljungman, Nikolaos Östlund-Papadogeorgos, Rickard Linder, Bassem Samad, Jonas Persson
  • Physiology (medical)
  • Cardiology and Cardiovascular Medicine
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Background: The prognostic implications of coronary microvascular dysfunction in an all-comer cohort with chronic coronary syndrome (CCS) are not known. Aim: To investigate the association of baseline resistance index (BRI), index of microcirculatory resistance (IMR), and thermodilution-derived resting- and hyperemic flow velocities (RFV and HFV) with the primary composite endpoint consisting of all-cause mortality, incident myocardial infarction (MI) or hospitalization due to congestive heart failure (CHF) in CCS.

Methods: CCS patients undergoing elective coronary angiography (CA) were included. Measurements of corrected IMR, BRI and mean transit time at baseline (Tmn base ) and during hyperemia (Tmn hyp ) were obtained in the LAD. RFV and HFV were calculated as 1/Tmn base and 1/Tmn hyp , respectively. Cox-regression was performed and Kaplan-Meier plots were constructed.

Results: We included 503 patients before the coronary anatomy was known and thermodilution measurements in the LAD were obtained in 413 patients. Median age was 68 (IQR 61-74), 127 (25%) were women and 151 (37%) had a flow-limiting epicardial lesion in the LAD. Median follow-up was 5.3 years (IQR 3.0-6.6) and there were 57 events. Log 10 BRI was inversely associated with the primary endpoint before and after fractional flow reserve (FFR) adjustments (HR 0.64 [95% CI 0.42 - 0.97]; Figure 1A). Log 10 IMR was not associated with the primary endpoint (HR 0.94 [95% CI 0.61 - 1.5]; Figure 1B). Log 10 RFV was associated with the primary endpoint before and after FFR- adjustment (HR 1.8 [95% CI 1.2 - 2.7]) whereas log 10 HFV was not (HR 1.2 [95% CI 0.75-1.8]).

Conclusion: Low microcirculatory resting resistance and high coronary resting flow velocity in the LAD, indicating impaired autoregulation, were associated with all-cause death, MI and/or CHF in CCS whereas hyperemic microcirculatory resistance and flow were not. Resting flow indices can be used for risk evaluation in patients with CCS undergoing CA.

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