Fig 1.
Origins and effects of waves within the coronary circulation.
A representative example of coronary pressure and flow velocity with calculated net wave intensity and separated wave intensity profiles measured over a single cardiac cycle is shown. Measurements were taken in the distal vessel, following stenting of the target stenosis during resting conditions. 6 major waves have been identified within the coronary circulation. These waves are hypothesized to explain coronary pressure and flow velocity over a complete cardiac cycle. Waves are numbered according to their sequence of arrival during the cardiac cycle (see Table 1). The early systolic forward travelling compression wave (sFCW) and early diastolic backward travelling decompression wave (dBEW) have been proposed as the primary accelerative forces acting on coronary flow. FFR, Fractional Flow reserve; CFVR, Coronary Flow Velocity Reserve; sFCW, systolic Forward travelling Compression Wave; dBEW, diastolic Backward travelling Expansion Wave.
Table 1.
Identified waves within the epicardial coronary circulation.
Proposed origins and effect on CBF of the 6 major coronary waves. Waves are presented in sequence of arrival over the cardiac cycle. Waves have been numbered to assist identification of waves in Fig 1.
Table 2.
Baseline Demographics.
Table 3.
Baseline Hemodynamic Parameters.
Table 4.
Changes in Cumulative Wave intensity following PCI during adenosine induced hyperemia.
Cumulative wave intensity profiles were generated using pressure and flow velocity signals acquired during hyperemia and SPc measured during resting conditions. The Wilcoxon Rank sum statistic was applied to estimate statistical significance.
Table 5.
Correlations between cumulative accelerative wave intensity and FFR / CFVR.
Correlations between FFR and CFVR measured distal to the lesion pre PCI with cumulative intensities of the two major accelerative coronary waves and the percentage change in cumulative intensity of these waves with PCI. The Spearman correlation coefficient was applied to estimate statistical significance.
Fig 2.
Relationship of Pre-PCI FFR / CFVR with Accelerative Wave intensity.
(A) Fractional Flow Reserve and cumulative intensity of the dBEW, (B) Coronary Flow Velocity Reserve and cumulative intensity of the dBEW, (C) Fractional Flow Reserve and cumulative intensity of sFCW. (D) Coronary Flow Velocity Reserve and cumulative intensity of the sFCW. Equations for the regression lines and 95% confidence intervals are shown. All measurements were taken distal to the stenosis, prior to PCI, during adenosine-induced hyperemia. FFR, Fractional Flow reserve; CFVR, Coronary Flow Velocity Reserve; sFCW, systolic Forward travelling Compression Wave; dBEW, diastolic Backward travelling Expansion Wave.
Fig 3.
Effect of PCI on accelerative wave intensity and relationship with pre-PCI FFR and CFVR.
(A) Cumulative intensity of the dBEW measured during hyperemia before and after PCI, (B) Percentage increase in dBEW intensity and pre-PCI FFR. PCI to lesions with the lowest baseline FFR values resulted in the largest percentage increase in diastolic suction wave intensity, whereas PCI to lesions with an FFR of close to 0.80 resulted in minimal increases. (C) Percentage increase in dBEW intensity and pre-PCI CFVR, (D) Cumulative intensity of the sFCW measured during hyperemia before and after PCI. (E) Percentage increase in sFCW intensity and pre-PCI FFR. PCI to lesions with the lowest baseline FFR values resulted in the largest percentage increase in sFCW intensity, whereas PCI to lesions with an FFR of close to 0.80 resulted in minimal increases. (F) Percentage increase in the sFCW intensity and pre-PCI CFVR. FFR, Fractional Flow reserve; CFVR, Coronary Flow Velocity Reserve; sFCW, systolic Forward travelling Compression Wave; dBEW, diastolic Backward travelling Expansion Wave.