Hyperemic coronary flow after optimized intravascular ultrasound-guided balloon angioplasty and stent implantation

OBJECTIVES This study evaluated the acute physiological gain of adjunctive intravascular ultrasound (IVUS) guided balloon angioplasty and stent implan tation. BACKGROUND Recent studies indicate safe coronary luminal enlargement and "s tent-like" long-term outcomes using upsized balloons guided by IVUS. METHODS After angiographically guided balloon angioplasty in 20 patients wi th 1-vessel disease and normal left ventricular function, IVUS was performe d to determine the size of the adjunctive balloon using the mean of the max imal luminal diameter and the maximal diameter of the external elastic memb rane measured in the adjacent proximal and distal reference segments. Seria l adenosine-induced hyperemic blood flow velocity measurements were perform ed using a 0.014 " Doppler guide wire to determine the physiological lumen obstruction after standard balloon angioplasty, followed by IVUS-guided bal loon angioplasty and stent implantation. RESULTS Upsized balloon angioplasty (increase balloon size: 0.98 +/- 0.26 m m; balloon:artery ratio 1.35 +/- 0.21) resulted in an additional increase o f arterial dimensions: minimal lumen diameter (MLD) 2.18 +/- 0.38 mm to 2.7 3 +/- 0.51 mm; percent diameter stenosis (%DS) 34 +/- 13% to 19 +/- 22%; IV US assessed minimal lumen area (MLA) 7.53 +/- 1.55 mm(2) to 10.24 +/- 2.22 mm(2) (all p < 0.0001). Major dissections (greater than or equal to type C) did not occur. Hyperemic blood flow velocity increased from 49.8 +/- 20.1 cm/s to 59.1 +/- 22.9 cm/s (p < 0.05) after IVUS-guided balloon angioplasty . Adjunctive stent implantation resulted in a further increase of MLD to 3. 84 +/- 0.51 mm, %DS to -9 +/- 21% and MLA to 13.39 +/- 1.80 mm(2) (all p < 0.0001), while hyperemic blood flow velocity remained unchanged (61.2 +/- 2 4.7 cm/s, p = 0.7). CONCLUSIONS Upsized IVUS-guided balloon angioplasty increases arterial coro nary dimensions and the distal hyperemic blood flow velocity. Adjunctive st ent implantation does not yield a further gain in the hyperemic blood flow velocity, indicating the absence of a functional residual lumen obstruction after IVUS-guided balloon angioplasty. This may explain a similar clinical outcome reported after those coronary interventions. (C) 1999 by the Ameri can College of Cardiology.