BackgroundLesion characteristics (anatomy, calcification, tortuosity and angulation), vessel morphology, and lack of support add complexity of coronary intervention. Guidezilla catheter, acting as an extension of guide catheter system (mother-in-child catheter), helps to overcome these complexities by enhancing backup during complex intervention.MethodsThe present retrospective, single-center study included 13,157 consecutive patients who underwent percutaneous coronary intervention (PCI) through both transfemoral and transradial routes from January 2015 to July 2019 at LPS Institute of Cardiology, G.S.V.M. Medical College, Kanpur, Uttar Pradesh, India among which Guidezilla™ catheter (Boston Scientific, Natick, MA, USA) was used in 156 patients. Study endpoints were target lesion crossing, procedural success, and complications. The clinical, angiographic and procedural data of all 156 patients were evaluated to assess safety and efficacy of Guidezilla extension catheter (GEC).ResultsThe mean age of the enrolled patients was 61.2 ± 8.67 years. Type-C lesion was commonest (69.9%) followed by B2 (22.4%) and B1 (7.7%). The commonest indication for its use was tortuosity (30.1%) followed by calcification (21.1%), angulation (18.8%), chronic total occlusion (17.9%), distally located lesion (8.3%), and anomalous origin of vessel in 3.8%. The right coronary artery (39.2%) was most commonly intervened artery followed by left anterior descending (LAD) (30.8%), left circumflex (LCX) (19.9%), multivessels (7.6%), and saphenous vein graft in 2.5%. The mean depth of intubation was 4.2 ± 1.9 cm. Mean diameter of stents was 34.2 ± 14.4 mm while mean length of stents was 31.2 ± 10.2 mm. Lesions were modified using aggressive pre-dilatation in 87.8%, followed by cutting balloon in 10.9%. GEC was delivered across the lesion using buddy wire technique (9.6%), balloon-assisted tracking (BAT) in 30.1%, and balloon-assisted sliding and tracking (BLAST) in 4.5% of patients. Stent implantation was successful in 151 out of 156 patients with success rate of 96.7%. Overall failure rate was 3.3% which was contributed by extreme tortuosity, angulation, and severe calcification. Guidezilla-associated procedural complication (dissection, stent dislodgement, shaft breakage) were reported in three patients (1.9%) who were successfully managed.Conclusions Guidezilla system acting as mother-in-child extension catheter is a safe and effective tool which provides additional backup support and increases success rate of PCI for complex coronary lesions.