778 IN-STENT USE OF INTRAVASCULAR LITHOTRIPSY IN THE TREATMENT OF STENT UNDEREXPANSION: A SYSTEMATIC REVIEW AND METAREGRESSION


 
 
 Calcified coronary plaque (CCP) represents a challenging scenario for interventional cardiologist. Stent Underexpansion (SU), often associated with CCP, can predispose to stent thrombosis and in-stent restenosis. To date, SU with heavily CCP can be addressed by means of scoring/cutting balloons, very-high/high pressure non-compliant balloons, off-label rotational/orbital atherectomy and intravascular lithotripsy (IVL).
 
 
 
 In this meta-analysis we investigate the success rate of IVL for the treatment of SU due to CCP.
 
 
 
 Studies and case-based experiences reporting on the use of IVL strategy for treatment of SU were included. The primary outcome was IVL strategy success, defined as adequate expansion of the underexpanded stent. Metanalysis was performed for the main focuses to calculate proportions of procedural success rates with corresponding 95% confidence intervals (CI). Random effects models weighted by inverse variance were used because of clinical heterogeneity.
 
 
 
 Our study included 13 studies with 354 patients. Mean age was 71.3 years (95% CI: 64.9-73.1) and 77% (95% CI: 71.2-82.4%) were male. The mean follow-up time was 2.6 months (95% CI: 1–15.3). Strategy success was seen in 88.7% (95% CI: 82.3–95.1) of patients. The mean Minimal Stent Area (MSA) was reported in 6 studies, pre-IVL value was 3.4 mm2 (95% CI: 3–3.8) and post-IVL value was 6.9 mm2 (95% CI: 6.5–7.4). The mean diameter stenosis (%) was reported in 7 studies, pre-IVL value was 69.4% (95% CI: 60.7–78.2) and post-IVL value was 14.6% (95% CI: 11.1–18). The rate of intraprocedural complications was 1.6% (95% CI: 0.3-2.9).
 
 
 
 The “stent-through” IVL plaque modification technique is a safe tool to treat SU due to CCP, with high success rate and very low incidence of complications.
