Significance of Microvascular Function in Visual—Functional Mismatch Between Invasive Coronary Angiography and Fractional Flow Reserve

Abstract

BackgroundDespite a moderate correlation between angiographical stenosis and physiological significance, the mechanism of discordance has not been fully elucidated, particularly regarding the significance of microvascular function. This study sought to clarify whether microvascular function affects visual‐functional mismatch between quantitative coronary angiography (QCA) and fractional flow reserve (FFR).Methods and ResultsWe assessed QCA, FFR, coronary flow reserve, and the index of microcirculatory resistance in 849 non‐left‐main coronary lesions with visually estimated intermediate stenoses from 532 patients. Clinical and lesion‐specific characteristics and physiological parameters associated with mismatch and reverse mismatch were studied. Coronary flow reserve and index of microcirculatory resistance showed a weak, but significant, correlation with FFR (R=0.306, P<0.001 and R=0.158, P<0.001, respectively). Four hundred twenty‐two lesions were visually nonsignificant (diameter stenosis assessed by QCA [QCA‐DS] ≤50%) and 427 lesions were visually significant (QCA‐DS >50%). Among visually nonsignificant lesions, FFR ≤0.80 (reverse mismatch) was observed in 129 lesions (30.6%). Among visually significant lesions, FFR >0.80 (mismatch) were observed in 179 lesions (41.9%). The significant predictors of reverse mismatch were male sex, nonculprit lesions of acute coronary syndrome, left anterior descending artery location, smaller QCA reference diameter, greater QCA‐DS, lower coronary flow reserve, and lower index of microcirculatory resistance. Mismatch was associated with right coronary artery location, greater QCA reference diameter, smaller QCA‐DS, lesion length, higher coronary flow reserve, and higher index of microcirculatory resistance.ConclusionsThere was a high prevalence of visual‐functional mismatches between QCA and FFR. The discrepancy was related to clinical characteristics, lesion‐specific factors, and microvascular resistance that was undistinguishable by coronary angiography, thus suggesting the importance of physiological lesion assessment.

Impact of Hydrostatic Pressure Variations Caused by Height Differences in Supine and Prone Positions on Fractional Flow Reserve Values in the Coronary Circulation

“…This study might explain the systematic differences in FFR values, wherein LAD supplying the anterior coronary territories had lower FFR values, whereas LCX and RCA with posterior coronary territories had higher FFR values. This may have led to the report that only 24.2% of LAD lesions achieved optimal poststent FFR (FFR ≥ 0.9), compared with 69.0% of LCX lesions and 70.4% of RCA lesions [18], and the results of the reverse mismatch in LAD and mismatch in LCX and RCA [10–12]. There is a possibility that the culprit may be mistaken as the moderate stenosis in LAD instead of the severe stenosis in the LCX or RCA.…”

“…Recently, systematic differences in FFR values between the anterior and posterior coronary territories have been observed: the left anterior descending artery (LAD) supplying the anterior coronary territories had lower FFR values, whereas the left circumflex artery (LCX) and right coronary artery (RCA) with posterior coronary territories had higher FFR values in the supine position [9]. A reverse mismatch in LAD and mismatch in LCX and RCA have been reported [10–12]. The influence of hydrostatic pressure on the intracoronary pressure measurements was recently demonstrated in vitro [13].…”

Functional classification discordance in intermediate coronary stenoses between fractional flow reserve and angiography-based quantitative flow ratio

“…This post-hoc analysis included patients from the data sets of previous studies from our institution performed from January 2011 to June 2017 12. All screened patients had suspected or known stable coronary artery disease and underwent invasive CAG with physiological lesion assessment using a pressure–temperature sensor-tipped guide wire (PressureWire; St. Jude Medical, St. Paul, MN, USA).…”

Determinants and prognostic implications of instantaneous wave-free ratio in patients with mild to intermediate coronary stenosis: Comparison with those of fractional flow reserve

“…Consecutive patients with stable CAD were enrolled between November 2013 and March 2017 at Kindai Hospital (Osakasayama, Japan). Patients eligible to participate had a lesion angiographically determined to be 30% to 80% diameter stenosis (DS) [11] and had undergone invasive physiological assessment before percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). Patients were exluded when they had acute coronary syndrome, left main coronary artery stenosis, and coronary artery bypass grafted lesions.…”