Stents Versus PAclitaxel Coated Balloons for Revascularization of CompleX and Small Coronary Vessels (SPARX) Trial

PCI with DES remains a cornerstone of interventional cardiology for the treatment of coronary artery disease. While DES have significantly improved outcomes compared to plain old angioplasty (POBA) and metal stents, there is still a risk of in-stent restenosis (ISR) and stent thrombosis (ST). To overcome these problems, non-stent techniques using only DCBs have emerged as a way of delivering anti-proliferative drugs to the vessel wall without the need for a permanent implant. It is hypothesised that this approach may promote positive remodelling and reduce the risk of vessel thrombosis and restenosis.

The use of PCI with DCB alone was first investigated for the treatment of ISR, where it showed good results and is currently recommended in guidelines for the treatment of ISR. There have also been several DCB trials in de novo coronary lesions, but the results have been more mixed. Many DCBs are now commercially available, both with paclitaxel and sirolimus coating, and it appears that there is no "class effect" due to the heterogeneity that exists within balloon designs, polymer coating, type of drug and concentrations used.

One of the first trials in de novo lesions, the PICCOLETO trial, was stopped early due to a higher MACE rate in the DCB group compared to the DES group. However, several weaknesses of the study may explain the worse outcome in those treated with DCBs compared to DES. The most important was probably the low dose of paclitaxel delivered by the balloon and the fact that only a small percentage of the population underwent lesion predilatation. Several studies have later shown non-inferiority of DCB to DES for de novo lesions, and the method is currently embraced by the interventional cardiology community.

Several DCBs are now available and approved for use, and more are on the way, but head-to-head data are scarce. The SPARX trial is designed to compare two DCBs, Protégé™ and Agent™, with conventional DES PCI in complex and small coronary lesions, with the idea that this type of coronary disease may benefit from a DCB-only technique. The trial will also compare the two certified and well-established paclitaxel-coated balloons, Protégé™ and Agent™. The hypothesis is that Protégé™ will perform at least as well as Agent™.

The primary objective of the SPARX trial is to compare paclitaxel-coated balloons with contemporary DES in complex and small coronary artery lesions in patients with non-ST elevation acute coronary syndrome (NSTEACS) or chronic coronary syndrome (CCS); The co-primary objective is to compare 2 different paclitaxel-coated balloons, Protégé™ and Agent™, with each other.