A new interventional strategy in complex coronary artery disease: drug-eluting balloons; clinical results and OCT analysis

Abstract

In the past decades, major progress has been made in the percutaneous treatment of coronary artery disease. Due to its simplicity and less invasive nature when compared to surgery the number of PCIs grew, while at the same time also the lesion complexity for PCI treatment increased. Despite this increasing number of procedures and the concomitant development of materials and techniques, three important drawbacks are still encountered when performing PCI: 1. Restenosis, 2. Stent thrombosis, and 3. Suitability of a specific device in a certain lesion subset. With regard to restenosis, the transition from balloon angioplasty to bare-metal stenting, and recently from bare-metal stenting to drug-eluting stenting resulted in significant reductions of revascularizations. However, also with DES certain drawbacks are still encountered. The most ominous complication following PCI, although less common than restenosis, is stent thrombosis. Stent thrombosis can result in severe clinical sequelae, leading to myocardial infarction (70-90%) and is associated to a high mortality rate (20-40%). Several factors are related to the occurrence of stent thrombosis: 1. Patient factors, 2. Lesion characteristics, 3. Procedural factors, and 4. Stent factors. The former 3 characteristics are unrelated to the use of a BMS or a DES. However, stent factors are foremost associated with DES rather than with BMS implantation. Concerning these stent factors, optical coherence tomography(OCT) studies demonstrate that stent strut uncoverage and malapposition is more often seen in DES than in BMS treated patients. This phenomena of morphological changes are also seen during autopsy studies in patients with stent thrombosis. More pronounced eosinophilic, macrophages, T-cells and mast cells involvement at the stent site has been described in DES treated patients, suggesting a hypersensitivity inflammation. These findings point toward a cascade in which DES treated patients are more prone to develop stent thrombosis when compared to BMS treated patients. It is believed this is due to an ongoing drug effect which hampers endothelial healing, and therefore abolishing the protective role of the endothelium. In addition, polymers on DES allow for a sustained release of the anti-restenotic drug. These polymers are also associated with an ongoing inflammatory response. Therefore an important extension of the DEB technology is avoiding the use of polymers, and therefore preventing an inflammatory response targeted to polymers as is seen in DES. Notwithstanding the anti-restenotic effects of DES, a device that can reduce an ongoing inflammatory response, which creates a pro-thrombogenic environment, is warranted. In this light we sought for an alternative option that could reduce restenosis when compared to BMS without leading to the above mentioned morphological changes, mainly seen in DES, which are associated with stent thrombosis.