Angiographic predictors of unplanned rotational atherectomy in complex calcified coronary artery disease: a pooled analysis from the randomised ROTAXUS and PREPARE-CALC trials

Background: Calcified coronary lesions present therapeutic challenges for the interventional cardiologist, often requiring rotational atherectomy (RA). Aims: This study aimed to develop an angiographic scoring tool to predict the need for a priori RA. Methods: A pooled analysis of the randomised ROTAXUS and PREPARE-CALC studies was carried out, (N=220 patients, N=313 lesions), by virtue of the fact that both studies made provision for crossover to RA (from balloon dilatation or modified balloon dilatation, respectively). Logistical regression techniques were employed to assess for the presence of patient- or lesion-specific factors leading to a necessity for RA. External validation was performed though retrospective calculation of the score for 192 patients who underwent bail-out RA in a single centre. Results: Lesion length (odds ratio [OR] 1.02, 95% confidence interval [CI]: 1.00-1.04 per mm, p=0.04), bifurcation lesion (OR 2.60, 95% CI: 1.27-5.30, p=0.009), vessel tortuosity >45 degrees (OR 3.49, 95% CI: 1.73-7.03, p<0.001) and severe vessel calcification (OR 11.60, 95% CI: 3.40-39.64, p<0.001) were predictive of the need for RA in multivariate analysis. Based on the regression coefficients, a scoring system was devised. The greater the score, the more likely a lesion required RA. The scoring system performed well in the external validation cohort, with 78% of patients crossing over having a score of greater than the proposed cut-off of 3. Conclusions: We provide an angiographic scoring tool to support the expeditious use of time and resources, allowing assessment of the likelihood of success of a balloon-based strategy, or the necessity for RA.