Insufficient tissue ablation by rotational atherectomy leads to worse long-term results in comparison with balloon angioplasty alone for the treatment of diffuse in-stent restenosis: insights from the intravascular ultrasound substudy of the ARTIST randomized multicenter trial.

The ARTIST trial demonstrated a worse outcome for patients with in-stent restenosis (ISR) treated with rotational atherectomy (RA) and adjunctive balloon angioplasty (PTCA) as compared to PTCA alone. This intravascular ultrasound (IVUS) substudy compares effects of lumen enlargement and examines reasons for failure of RA in this setting. IVUS (n = 56) was performed after each interventional step and at follow-up. Volumetric lumen gain measured 79 +/- 68 mm(3) after PTCA (13 +/- 4 atm) as compared to 44 +/- 26 mm(3) after RA and adjunctive PTCA (7 +/- 3 atm; P < 0.0001). RA itself enlarged lumen by only 19 +/- 17 mm(3) and stent volume was 47% smaller as compared to high-pressure PTCA. Low-pressure strategy after RA did not prevent tissue growth during follow-up (19 +/- 25 vs. 36 +/- 38 mm(3); RA vs. PTCA; P = 0.09). Consequently, net lumen gain after PTCA was 82% higher compared to RA (46 +/- 54 vs. 25 +/- 24 mm(3); P = 0.09). Further stent expansion is the key mechanism to achieve luminal gain by PTCA of ISR. Neointimal ablation by RA has only minor effects. Low-pressure PTCA does not prevent recurrent tissue growth and failed for treatment of ISR due to insufficient stent expansion.