Dr. Lino Manuel Goncalves,
This was an exciting session dealing with some of the most difficult lesion subsets in coronary intervention. The congress program committee selected highly experienced interventional cardiologists to address these difficult topics. Martine Gillard, from Brest, France, had the task to talk about the problem of drug eluting restenosis, a situation for which we still do not have a definitive solution and which is not totally benign. She introduced the topic with an historic perspective of the evolution of the restenosis rate from balloon, to bare metal stents (20-30%) to current drug eluting stents (3-8%). She then showed the clinical and angiographic definitions of restenosis, and the different patterns of drug-eluting restenosis described by Mehran et al. Furthermore, Martine Gillard also discussed the biological, mechanical and technical mechanisms involved in this process. She stated that in DES, neoatherosclerosis is more frequent and occurs earlier than in BMS. Stent fractures, polymer peeling and non-uniform drug distribution can also contribute for this situation, as well as under-expansion of the stent. Finally she discussed the techniques we can use to treat restenosis in this clinical setting. One possibility is to use a DES inside the previous DES, another one is to use a drug-eluting balloon. The PEPCAD-DES study published by Rittger et al, in 2012, showed that drug-eluting balloon is better than simple balloon in the treatment of DES. She concluded, with a word of hope, saying that advances in drugs and biodegradable stents are likely to provide effective solutions for prevention of restenosis in the future. Goran Stankovic from Belgrade, Serbia, gave his personal perspective on how to treat “real bifurcations”. He started by saying that bifurcations can be found in 15-20% of the PCIs and that they need an individualized approach due to baseline variations in anatomy, and to dynamic changes in anatomy during treatment. He explained the rational of Murray’s law showing that the mother vessel is usually 70% smaller than the sum of the two daughter vessels. He explained the Medina Classification and showed some of the clinical trials that compared one vs two-stent strategy. He defended the view that one stent is better for the treatment of bifurcation lesions, and stated that one vessel stenting strategy with provisional stenting of the side branch is the reference technique for most patients with CAD. He recommended that according the Murray’s law the size of the stent should be the one of the distal vessel. Postdilatation, or kissing balloon techniques are required to optimize the proximal main vessel stent diameter. He also said that should one experience difficulties recrossing into the side branch then the proximal optimization technique must be used. He showed data supporting the view that routine final kissing balloon did not improve clinical outcome, but there was not a penalty in doing so. According to his experience in less than 15% of cases a systematic two stents approach is planned. Furthermore, he also explained the T-stenting, TAP, Internal crush, and Culotte techniques. Finally, he stated that dedicated bifurcation devices are still limited and that RCTs comparing these dedicated stents with provisional stenting are lacking. Olivier Muller from Lausanne, Switzerland, had the task to discuss the topic: PCI in patients with large thrombus burden. He showed that an adverse outcome can be expected in the presence of a large thrombus burden. After explaining the thrombosis grade classification, he stated that several mechanical and pharmacological management tools have been tested in large randomized clinical trials for the prevention of distal embolization in patients with AMI. However, specific treatments for large thrombus have been reported only in small studies. Large thrombus burden has been associated with a worse prognosis. For the treatment of this situation there is the possibility of using aspiration and protection devices. Manual aspiration has been shown to be better than conventional treatment, but not in a definitive way. Large RCT are needed to evaluate the efficacy of thrombectomy device/pharmacotherapy according to thrombus grade. The addiction of GP IIb/IIIa inhibitors to thrombectomy is not associated with a significant clinical benefit. According to the recently published ESC guidelines, these agents are currently a classe IIa C indication when there is an angiographic evidence of massive thrombus, slow or no-reflow or a thrombotic complication. Finally, Dr. Muller presented an algorithm for the treatment of no-reflow that he published in 2008. Michael Haude, from Neuss, Germany presented the topic of PCI in degenerated saphenous vein grafts. He first showed the pathology of this situation. The most frequent complication of PCI in these vessels is low or no-reflow. This is due to distal embolization not only of thrombus, but also of atherosclerotic plaque materials. Vasoactive substances and inflammation can also play an important role in this situation, in particular, serotonin and TNF-alpha have an important role. No-reflow is associated with a rise of CK-MB. Increase in CK-MB is associated with increase mortality. Verapamil and adenosin were tested for the prevention of no-reflow in saphenous graph intervention. Verapamil, did not show any benefit, however adenosine, despite the fact that does not prevent slow or no-reflow, can effectively treat the no-reflow during PCI. Best results were obtained when adenosin was associated with sodium nitroprussiate in the prevention and treatment of slow/no-reflow. GP IIb/IIIa inhibitors were tested in this setting but they did not show any benefit in a meta-analysis published by Roffi in 2002. Mechanical embolic protection devices can also be used to prevent slow/no-reflow. These devices have several advantages and disadvantages. In fact, the 2010’ ESC guidelines gave a class IB indication for the use of distal protection devices, and a class IIb B for the use of proximal protection systems. Finally, Dr. Michael Haude addressed the selection of the type of stent in this scenario. PTFE covered BMS compared to BMS have failed to limit no reflow during SVG-PCI. DES seems to be better than BMS particularly in reducing restenosis and reintervention. The use of IVUS-guided undersizing of DES in SVGs, can be used, in order to reduce plaque prolapse.
The grey zone of coronary interventions
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