Functional Formula to Determine Adequate Balloon Diameter of Simultaneous Kissing Balloon Technique for Treatment of Bifurcated Coronary Lesions Clinical Validation by Volumetric Intravascular Ultrasound Analysis

BACKGROUND: Final kissing balloon technique (KBT) is known to alter long-term clinical outcomes for treatment of bifurcated coronary lesions. However, determination of adequate diameters of the 2 balloons remains difficult because of lack of a working index. METHODS AND RESULTS: Twenty-one cases of left main (LM)-related bifurcated lesions, treated with Cypher(TM) stents (single/crush stenting) and final KBT, were enrolled. The formula "R(2) = D(1)(2) + D(2)(2)" was used, adjusting balloon diameter (D(1), D(2)) to the downstream branches, to predict the theoretical mean hugging balloon diameter (R) within the main portion. The degree and pattern of stent expansion in the LM and main branch (MB) segments was compared by volumetric intravascular ultrasound assessment. Stents in the LM segments expanded to a greater extent and more asymmetrically than in MB segments (average stent area: 13.2+/-3.1 mm(2) vs 7.6+/-2.1 mm(2), p<0.0001, stent symmetry index: 0.77+/-0.08 vs 0.88+/-0.03, p<0.0001). The actual mean stent diameter significantly correlated with R (p=0.0003, r=0.76). The ratio of actual to theoretical stent expansion was highly consistent between the LM and MB (93.1% vs 93.4%, p=NS). CONCLUSION: The proposed formula may be useful for predicting resultant stent expansion following KBT, despite a more elliptical dilation.