Transcatheter aortic valve implantation: patient selection.

Transcatheter aortic valve implantation (TAVI) is a disruptive technology as it satisfies a previously unmet need which is associated with a profound therapeutic benefit. In randomized clinical trials, TAVI has been shown to improve survival compared with medical treatment among patients considered not suitable candidates for surgical aortic valve replacement (SAVR), and to provide similar outcomes as SAVR in selected high-risk patients. Currently, TAVI is limited to selected elderly patients with symptomatic severe aortic stenosis. As this patient population frequently suffers from comorbid conditions, which may influence outcomes, the selection of patients to undergo TAVI underlies a complex decision process. Several clinical risk score algorithms are routinely used, although they fall short to fully appreciate the true risk among patients currently referred for TAVI. Beyond traditional risk scores, the clinical assessment by an interdisciplinary Heart Team as well as detailed imaging of the aortic valve, aortic root, descending and abdominal aorta as well as peripheral vasculature are important prerequisites to plan a successful procedure. This review will familiarize the reader with the concepts of the interdisciplinary Heart team, risk scores as well as the most important imaging algorithms suited to select appropriate TAVI patients.

Update on transcatheter aortic valve implantation registries and studies.

For patients at increased surgical risk and those not suitable candidates for surgical aortic valve replacement, transcatheter aortic valve implantation has emerged as a promising less-invasive treatment option, with a growing body of evidence on safety and efficacy in this particular patient population. However, the enthusiasm we have been witnessing over the past decade is almost exclusively supported by registry data, with the first randomized trial published only recently. In this paper, we provide an overview on the current data set available on transcatheter aortic valve implantation using the commercially available devices, focusing on the latest publications reflecting the current opinion on this emerging technology.

Comparative endoluminal visualization of TAXUS crush-stenting at 9 months follow-up by intravascular ultrasound and optical coherence tomography.

We report a case of crush-stenting with Paclitaxel-eluting TAXUS stents in a left anterior descending artery (LAD) bifurcation lesion. In order to obtain precise information on the mid-term neointimal response of the main vessel to this approach, we evaluated the patient angiographically 9 months later, including intravascular visualization with optical coherence tomography (OCT), a new high resolution imaging technique, and IVUS. The evaluation revealed that there was a homogeneous neointimal coverage of the main vessel stents without evidence of significant recurrent lumen renarrowing or malappositions. Compared to IVUS, OCT proved the coverage of the stent struts adjacent to the vessel wall with a superior imaging quality and, in addition, provided new insights into the stent performance at the open bifurcation site.

Drug-eluting stents: clinical experiences and perspectives.

Drug-eluting stents (DES) have entered the arena and are about to changed the landscape of Interventional Cardiology. Today, the number of agents under preclinical and clinical investigation has increased considerably, including drugs such as Paclitaxel, Sirolimus, Tacrolimus, Everolimus, Dexamethasone, etc. Several studies have recently been published or are still ongoing evaluating different stent designs with respect to their safety and efficacy in treatment of coronary lesions. The SCORE trial (Paclitaxel) revealed a significant reduction in restenosis at follow-up (FU) in the drug-eluting stent group (6.4% vs 36.9% control group), attributable to decreased intimal proliferation. However, stentthromboses and myocardial infarctions, due to both stent design and high drug dosages, were observed causing a MACE rate of 10.2% in the DES group. Confirming the beneficial reduction of stent renarrowing using a local drug-eluting device, the rate of restenosis in the TAXUS-I trial (Paclitaxel) was 0% at follow-up in patients with DES vs 10% in patients with bare stents. Differences in MACE were not observed, which underlined the potential impact of an optimal stent design. First clinical experiences with a Sirolimus-coated stent (FIM trial) demonstrated again a profound inhibition of neointimal ingrowth at 4-month follow-up. The RAVEL trial, the first multicenter trial evaluating the Sirolimus stent and the largest DES study published so far, confirmed the FIM findings with a rate of restenosis in the DES group of 0% at 6 month FU. At 12 month FU, the beneficial impact on neointimal growth inhibition was persistent. The pivotal study SIRIUS is addressed to evaluate this stent design more extensively. However, given all the results being available today, local application of anti-proliferative agents delivered by coronary stents is one of the most promising techniques in treatment of coronary lesions. Nevertheless, we need more trials and an agreement of definitions in order to evaluate this treatment concept and eliminate unwanted side-effects.