Deciding on coronary intervention: which lesion, which stent?

Download the Issue @ a Glance podcast Subscribe to the EHJ Podcast The primary goal of coronary intervention is the relief of myocardial ischaemia.1 Thus, any lesion under consideration has to be severe enough to induce ischaemia either at rest2,3 or during exercise.4 In stable coronary artery disease, appropriate coronary stenting therefore has to ensure that a given lesion is haemodynamically significant.5 Unfortunately the commonly used visual assessment of coronary lesion is often inappropriate, particularly in moderate or eccentric stenosis.6 This has increased interest in coronary physiology to guide decision-making. Measurement of coronary pressure to calculate the fractional flow reserve or FFR is increasingly used to overcome the shortcomings of the oculo-stenotic reflex.7 While accumulating evidence supports the contention that FFR-guided revascularization is superior to revascularization based on coronary angiography, it is frequently overlooked that FFR is a coronary pressure-derived estimate of coronary flow impairment; it does not directly reflect coronary flow. Tim van de Hoef and colleagues from the Academic Medical Center in Amsterdam, The Netherlands thoroughly discuss this issue in their Review article ‘Fundamentals in clinical coronary physiology: why coronary flow is more important than coronary pressure’.8 They point out that coronary flow is physiologically and clinically more important than coronary pressure, and outline the resulting limitations and clinical consequences of FFR-guided clinical decision-making. Adnan Kastrati from the Deutsches Herzzentrum in Munich, Germany gave the Andreas Grüntzig Lecture at the European Society of Cardiologly's Annual Congress in Barcelona and summarizes its content in his Clinical Review entitled ‘Stent thrombosis and restenosis: what have we learned and where are we going?’9 He dwells on his extensive experience over the last decades and summarizes the impressive progress made in percutaneous coronary intervention (PCI) since the introduction of stents in the 1980s.10 The two major causes of stent failure are stent thrombosis11 and in-stent restenosis.12 The incidence of both has been reduced dramatically in recent years. In current clinical registries and randomized trials with broad inclusion criteria, the rates of stent thrombosis are <1% after 1 year and ∼0.2–0.4% per year thereafter, while the reported rates of clinical in-stent restenosis are 5%. Conversely, angiographic surveillance studies in large cohorts revealed rates of angiographic restenosis of ∼10% with new generation. The advent of high-resolution intracoronary imaging has shown that in many cases of late stent failure neoatherosclerotic change within the stented segment13 underlies both thrombotic and restenotic events. In the future a better understanding of the pathogenesis of this process may translate into improved late outcomes. Moreover the predominance of non-stent-related disease as a cause of subsequent myocardial infarction during follow-up14 highlights the importance of lifestyle and pharmacological interventions targeted at modification of the underlying disease process. A new development in coronary intervention is the bioresorbable vascular scaffold15 which might offer advantages as compared with permanent metallic drug-eluting stents, such as improved vascular healing,15 near normal coronary vasomotion16 options for later bypass surgery, and possibly better outcome. In an ESC FAST TRACK paper entitled ‘A randomized trial evaluating everolimus-eluting absorb bioresorbable scaffold vs. everolimus-eluting metallic stents in patients with coronary artery disease: ABSORB Japan’,17 Takeshi Kimura from the Kyoto University Graduate School of Medicine in Japan reports the results of his single-blind, multicentre, active-controlled, randomized trial designed to support regulatory approval of the Absorb BVS in their country. Four hundred patients with one or two de novo lesions were randomized at 38 Japanese sites in a 2:1 ratio to Absorb bioresorbable scaffold or cobalt chromium everolimus-eluting stents, respectively. The primary endpoint was target lesion failure, i.e. a composite of cardiac death, myocardial infarction attributable to target vessel, or ischaemia-driven target lesion revascularization at 12 months, powered for non-inferiority. Target lesion failure was 4.2% with a bioresorbable scaffold and 3.8% with an everolimus-eluting stent. Definite or probable stent or scaffold thrombosis, respectively, occurred in 1.5% with both devices. Ischaemia-driven target lesion failure for restenosis was infrequent (1.1% with the bioresorbable scaffold and 1.5% with an everolimus-eluting stent, respectively). With 96.0% angiographic follow-up, in-segment late lumen loss was 0.13 ± 0.30 mm with a bioresorbable scaffold and 0.12 ± 0.32 mm with an everolimus-eluting stent. The authors conclude that 12-month clinical and 13-month angiographic outcomes of bioresorbable scaffold were comparably non-inferior to an everolimus-eluting stent. The manuscript is accompanied by an Editorial by Steen Dalby Kristensen from the Aarhus University Hospital in Denmark.18 Of note, the manuscript relates to an EHJ Today video interview.19 In the second ESC FAST TRACK paper, entitled ‘Optical coherence tomography imaging during percutaneous coronary intervention impacts physician decision-making: ILUMIEN I study’,20 William C. Wijns and colleagues from the OLV Hospital in Aalst, Belgium publish the results of ILUMIEN I, the largest prospective observational study of PCI practice in patients undergoing intraprocedural pre- and post-PCI determination of FFR and optical coherence tomography.21 They analysed the impact of optical coherence tomography on physician decision-making and the association with post-PCI FFR values and early clinical events in 418 patients with stable or unstable angina or non-ST-segment elevation myocardial infarction (NSTEMI). Based on pre-PCI optical coherence tomography, the procedure was altered in 55% of patients by selecting different stent lengths. After clinically satisfactory stent implantation using angiographic guidance, post-PCI FFR and optical coherence tomography were repeated and abnormalities deemed unsatisfactory identified: 14.5% malapposition, 7.6% underexpansion, and 2.7% edge dissection. This prompted further stent optimization in 25% of patients using additional in-stent post-dilatation or placement of 20 additional stents. Further optimization subgroups were identified post-hoc: stent placement without reaction to optical coherence tomography findings, change in PCI planning by pre-PCI optical coherence tomography, post-PCI optimization based on post-PCI optical coherence tomography, and change in PCI planning and post-PCI optimization based on optical coherence tomography. Post-PCI FFR values were significantly different between optimization groups, but no longer different after post-PCI stent optimization. The authors conclude that physician decision-making was affected by optical coherence tomography imaging prior to PCI in 57% and post-PCI in 27% of cases. The manuscript is accompanied by an Editorial by Ron Waksman from the Washington Hospital Center in the USA.22 In symptomatic patients with suspected coronary artery disease, computed tomographic angiography improves patient selection for invasive coronary angiography compared with functional testing.23 In the third ESC FAST TRACK paper ‘Clinical outcomes of fractional flow reserve by computed tomographic angiography-guided diagnostic strategies vs. usual care in patients with suspected coronary artery disease: the prospective longitudinal trial of FFRCT: outcome and resource impacts study’,24 Pamela S. Douglas and colleagues from the Duke University Medical Center in Durham, North Carolina, USA investigated the impact of measuring FFR by computed tomography (FFRCT) in 584 patients with new-onset chest pain assigned to receive either usual testing or FFRCT. The primary endpoint was the percentage of those with planned invasive angiography in whom no obstructive lesions, i.e. no stenosis ≥50% or invasive FFR <0.80, were found. Of those with intended invasive angiography, among them 193 FFRCT-guided and 187 usual care, no obstructive coronary disease was found at invasive angiography in 12% in the CTA/FFRCT arm and 73% in the usual care arm (P < 0.0001). Invasive angiography was cancelled in 61% after receiving the FFRCT results. Among those with intended non-invasive testing, the rates of finding no obstructive coronary disease were 13% with CTA/FFRCT and 6% with usual care. The authors therefore conclude that FFRCT is feasible and safe and was associated with a significantly lower rate of invasive angiography showing no obstructive coronary artery disease. The clinical implications are further discussed in an Editorial by Troy LaBounty and Brahmajee Nallamothu from the University of Michigan, USA.25 In addition to that, this issue is also the subject of an EHJ Today video interview filmed during the ESC 2015 congress in London.26 The majority of transcatheter aortic valve implantation or TAVI procedures are currently done by a percutaneous transfemoral approach.27,28 Due to the catheter size required, access bleeding is still a major complications of the procedure.29 However, the efficacy of vascular closure devices to reduce the incidence of vascular complications is not clear. In the fourth FAST TRACK paper, entitled ‘Comparison of vascular closure devices for access site closure after transfemoral aortic valve implantation: the ClOsure devices iN TRansfemoral aOrtic vaLve replacement (CONTROL) multicentre study’,30 Israel Moshe Barbash and colleagues from the The Chaim Sheba Medical Center in Ramat Gan, Israel compared the efficacy of the Prostar XL and Perclose ProGlide-based closure device in 3138 patients undergoing percutaneous transfemoral TAVI. Propensity score matching was used to assemble a comparator cohort consisting of 635 patient pairs. Major vascular complications or in-hospital mortality occurred more frequently in the Prostar as compared with the ProGlide group, i.e. 10.9% and 4.7%, respectively. This effect was driven by higher rates of major vascular complications in the Prostar group, i.e. 7.6% and 1.7%, while in-hospital mortality was similar. Prostar use was also associated with higher rates of life-threatening bleeding and major bleeding, and with longer hospital stay. Failed haemostasis, including arterial rupture and haematomas, accounted for the differences in vascular complications between groups. Thus, the authors conclude that Prostar-based vascular closure is associated with higher major vascular complication rates as compared with ProGlide, while in-hospital mortality is similar with both devices. The editors hope that this issue of the European Heart Journal will be of interest to its readers.