UTILITY OF NON-INVASIVE CORONARY FLOW PATTERN VERSUS FRACTIONAL FLOW PRESSURE DROP FOR LEFT ANTERIOR CORONARY ARTERY STENTING

Background and Aim: To assess the usefulness of coronary flow reserve as a guide in patient with left anterior descending coronary artery lesion during percutaneous coronary intervention in comparison with fractional flow reserve.
Methods: The study included 80 patients with left anterior descending artery stenotic lesions, proved by coronary angiography, in the cardiac catheterization laboratory of the Faculty of Military Hospital, during the period from November 2012 to June 2014. All patients were subjected to all of the following: Complete history taking, full general and local examination, ECG analysis. All our patient were assessed by Doppler wire to measure pressure drop at LAD lesion and also by non-invasive coronary flow pattern utilizing transthoracic echo-Doppler study. Then we compare the results of both values on the basis of the improvement in left ventricular ejection fraction( by biplane Simpson rule) to find the cut point at which we can document that this LAD lesion deserve stenting .
Results: FFR was negatively correlated with significant correlation with EF improvement with R value of -0.575 and P-value of 0.008,figure. Also there is strong inversed relation with lesion percent with R-value of-0.468 and P-value of 0.01. The correlation between FFR and improvement in wall motion score was significantly inversed with R-value of -0.519 and P-value of 0.03. Also there was strong correlation between FFR and CFR ,P-value was 0.00 and R-value was+0.436.
CFR has strong reciprocal correlation with FFR (P-value was 0.00 and R-value was. inve+0.436. There is significant correlation of CFR with EF improvement with R value of -0.583and P-value of 0.002. Also there is significant correlation of CFR with lesion percent with R-value of -0.585and P-value of 0.001, figure. The correlation between CFR and wall motion score was significant with R-value of-0.393 and P-value of 0.03.
The optimal cutoff values for coronary flow reserve of <1.75 was the best value for indication of stenting of an intermediate coronary lesion. A sensitivity of 92% and a specificity of 87%. On the other hand the best cut-of value of fractional flow reserve was <0.75 for indication of stenting for an intermediate coronary artery lesion with a sensitivity of 94% and specificity of 86%.
Conclusions: The current study showed Coronary flow reserve measurements by TTE in the distal to mid LAD were feasible in most patients with an optimal cut-off value < 1.75 showed high accuracy to detect angiographically significant stenoses in the LAD. This is comparable to <0.75 as an optimal cut-off value of FFR to detect angiographically significant stenoses. CFR measurement utilizing TTE might be considered as a simple non-invasive tool for functional status of an intermediate coronary artery lesion for stenting.