LAUSR

Background: There is uncertainty about relation between clinical and angiographic characteristics and functional significance of bifurcation stenosis. Methods: We analysed patients from FIESTA registry (ClinicalTrials.gov:NCT01724957). Subjects (>18 years) with stable angina, bifurcation lesions with diameter ≥2.5mm and ≤4.5 mm, SB diameter≥2.0 mm were included. We excluded patients with ST-segment elevation myocardial infarction, left main disease, hemodynamic instability. Provisional stenting was the default strategy in all patients. Fractional flow reserve(FFR) was performed using the PrimeWire or PrimeWire Prestige(Volcano Corp., USA). Bifurcation lesion with FFR above 0.80 were deferred from PCI. Results: A total of 171 patients, mean age 67±10 years, 66% males were included in the analysis. Of them 78(46%) had functionally significant bifurcation lesion (FSL) versus 93(54%) with non-significant lesion (nFSL). There were no differences (FSLvs.nFSL) in baseline characteristics: dyslipidemia(88%vs96%), diabetes(44%vs.32%), smoking (52%vs40%), past MI (24%vs15%), previous PCI(54%vs49%), atrial fibrillation (17%vs29%), peripheral artery disease (10%vs9%), renal failure(29%vs31%) –all p>0.05. On logistic-regression analysis independent predictors of functional significance were: SYNTAX score≥11 (OR=5.523,CI:1.666-18.311,p=.005), lesion length≥25mm (OR=21.737,CI:4.963-95.202,p<.001),MV%DS≥55%(OR=9.535,CI:2.508-34.883,p=.001) and MB%DS≥65% (OR=12.927,CI:3.015-55.418,p=.001). We created score for prediction of functional significance of bifurcation lesion with the following parameters: SYNTAX ≥11 gives 1 point, SB BARI≥12%- 1 point, MV%DS ≥55%- 1.5 point, MB%DS≥65%- 2 points, lesion length ≥25 mm – 3 points. The overall performance of the score was excellent with AUC=.960, p<.001. With a cut-off value ≥4.5 points it has sensitivity of 90%, specificity 91%, accuracy 90%, p<.001. Conclusion: Different degree of stenosis in proximal main vessel and distal side branch, lesion length, SB myocardium territory and SYNTAX score are significant predictors of functional severity of bifurcation lesion. A score based on those parameters was developed with excellent discriminatory ability.