Ischemia-Guided Percutaneous Revascularization

Abstract

Submit Manuscript | http://medcraveonline.com The study of Hachamovitch et al. [3] emphasized the relationship between inducible ischemia on SPECT and the presence of shortterm survival benefits with early revascularization vs. medical therapy.Revascularization was associated with a reduction in mortality for patients having moderate to severe ischemia. The cut-off level of ischemic myocardium, assessed by summed stress scores, to predict lower mortality using revascularization was approximately 10-12.5% [3]. Kim et al. [4] supported the benefit of ischemia-guided revascularization with myocardial perfusion imaging for patients with multivessel coronary artery disease. The outcomes of ischemia-guided revascularization were retrospectively compared with those of non ischemiaguided revascularization in a registry of 5,340 patients with multivessel coronary disease comprising 2,587 percutaneous coronary interventions (PCIs) with drug-eluting stents and 2,753 coronary artery bypass graft (CABG) surgeries. The incidence of major adverse cardiac and cerebrovascular events (MACCE) was significantly lower in the ischemia-guided than in the non ischemia-guided group, primarily driven by the lower repeat revascularization rate. Subgroup analysis showed that ischemiaguided reduced the risk of MACCE in PCI but not in CABG patients [4]. Several diagnostic modalities are available for use as tools to establish the initial diagnosis, assess disease severity, and select the appropriate treatment strategy in symptomatic patients suspected of having SCAD. In relation to this point, a multicenter study performed in Japan hypothesise that the choice of the initial diagnostic test might influence the treatment strategy. They showed that patients receiving initial SPECT had a lower rate of revascularization than those receiving coronary angiography [5]. In relation to invasive methods assessing ischemia, fractional flow reserve (FFR) is considered nowadays the elective way for invasive assessment of physiological stenosis significance and a decisive tool for decision making in coronary revascularization. The recently published ESC guidelines on the management of stable coronary artery disease endorse the use of FFR for risk stratification. FFR is calculated as the ratio of distal coronary pressure to aortic pressure measured during maximal hyperaemia. A normal value for FFR is 1.0. Stenoses with a FFR >0.80 are hardly ever associated with exercise-induced ischaemia [6]. The principal utility of FFR is in certain situations when it is not clear whether an intermediate angiographic lesion causes ischemia. The use of FFR in the catheterization laboratory accurately identifies which lesions should be revascularized and improves the outcome in most elective clinical and angiographic conditions, as compared with the situation where revascularization decisions are simply made on the basis of angiographic appearance of the lesion [7]. The DEFER study evaluated the 5-year outcomes in 325 patients assigned to 3 groups: deferred group (FFR ≥0.75 without PCI), PCI group (FFR ≥0.75 with PCI), and a control group (FFR <0.75 with PCI). 5-year event-free survival rates were similar in the deferred and PCI groups, with a risk of cardiac death or MI in patients with normal FFR inferior to 1% per year [8]. FAME study evaluated angio-guided versus FFR-guided percutaneous revascularization in patients with multivessel disease. Routine measurement of FFR in patients with multivessel coronary artery disease who were undergoing PCI with drug-eluting stents significantly reduced the rate of the composite end point of death, nonfatal myocardial infarction, and repeat revascularization at one year of follow up [9]. The 2-year outcome report of the FAME study supported the safety of deferring PCI for non ischemic lesions [10]. Of interest, a sub analysis of the FAME study also showed that angiography is inaccurate in assessing the functional significance of a coronary stenosis when compared with the FFR in the 50% to 70% category but also in the 70% to 90% angiographic severity category [11]. The FAME-2 trial tested the benefits, for SCAD, of FFR-guided PCI plus optimal medical therapy with optimal medical treatment alone. PCI group had significant lower rate of primary endpoint event: death, MI, or urgent revascularization. Also there was a lower rate of urgent revascularization in the PCI group than in the medical therapy group [12].