One balloon approach for optimized Palmaz-Schatz stent implantation: the MUSCAT trial

After stent deployment, larger balloons are frequently needed to optimize stent expansion according to angiographic and intravascular ultrasound (IVUS) criteria. The objective of this trial was to assess the feasibility and safety of a single-balloon approach for predilation, stent implantation, and optimization with a differential-compliant balloon allowing for focal overexpansion. We also evaluated the achieved degree of stent expansion according to IVUS criteria.

Forty-seven consecutive patients with 50 lesions received single or multiple Palmaz-Schatz coronary stents. The final angiographic diameter stenosis was -2.6 +/- 12.6% (reference diameter, 2.89 +/- 0.44 mm), and the residual lumen area stenosis (IVUS) was 13.0 +/- 12.3% (reference area 10.8 +/- 3.0 mm2). This result was achieved in two steps (first angiographic, then IVUS-guided stent optimization). The balloon inflation pressure increased from 13.1 +/- 3.0 bar at step 1 to 16.1 +/- 3.0 bar at step 2, which resulted in a balloon to artery ratio of 0.97 +/- 0.12 and 1.10 +/- 0.15, respectively, at the low-compliant peripheral balloon segments. The more compliant central balloon segments showed a balloon to artery ratio of 1.09 +/- 0.17 and 1.28 +/- 0.17, respectively. The primary success rate for stent deployment was 94%. Acute complications included two type A and one type B dissection without clinical sequelae.

The single-balloon approach for stenting is feasible and safe. The acute result is comparable to that of other studies with IVUS-guided stent optimization, the primary success rate, however, is slightly lower with the presently available catheter.