Author + information
The aim of this study is to explore and compare intracoronary electrocardiography (i.c.ECG) abilities to detect acute ischemia with FFR hemodynamic assessment during PCI of bifurcation lesions.
A total of 39 patients were selected based on occurrence of hemodynamically significant stenosis in main vessel. Provisional stenting was the default PCI procedure. We measured FFR and i.c. ECG values in main branch and side branch before and after stenting the main vessel, which guided our side branch treatment decision. Intracoronary ECG was recorded with uninsulated proximal wire ends connected to unipolar V leads. FFR was measured using pressure wire after i.c. adenosine bolus.
Overall 18 patients had side branch FFR ≤ 0.80 after stenting the main vessel and 22 patients had ST-segment elevation on icECG. From the patients with FFR ≤ 0.80, only two did not have ST-segment elevation on icECG, but both patient had FFR > 0.75 (0.77 and 0.78). After performing a receiver operated curve analysis to define a cut-off value to SB FFR after stenting, we defined a new cut-off value of 0.77 for SB FFR after stenting with c-statistic of 0.921, sensitivity of 100%, and specificity of 77%. There was a significant correlation between absolute measures of SB FFR after stenting and ST-segment elevation in millimeters on icECG (r=-0.533, p < 0.001). There was a significant difference of SB FFR values in groups with icECG STS elevation, without any overlap in variation ranges (p < 0.001). Neither STS elevation on icECG nor FFR in SB after stenting correlated significantly with ostial or minimal percentage diameter stenosis at SB, but there was significant correlation of both parameters with final SB ostial percentage diameter stenosis (SB icECG STSE: r = -0.396, p = 0.025, SB FFR: r = 0.369, p = 0.038). The only other parameter which correlated significantly with both FFR and icECG STSE was SB maximum ST-segment elevation during first balloon implantation or during stent implantation (SB icECG STSE: r = 0.798, p < 0.001, SB FFR: r = -0.455, p = 0.020).
Intracoronary ECG has excellent ability to predict hemodynamically significant stenosis (based on critical value of FRR) occurrence at SB ostium after MV stenting. This method provides a link between a direct measure of ischemia (icECG changes) and flow limiting capacity of stenosis (FFR).
IMAGING: FFR and Physiologic Lesion Assessment