Coronary revascularization guided by fractional flow reserve (FFR) is associated with better patient outcomes after the procedure than revascularization guided by angiography alone. It is unknown whether the instantaneous wave-free ratio (iFR), an alternative measure that does not require the administration of adenosine, will offer benefits similar to those of FFR. We randomly assigned 2492 patients with coronary artery disease, in a 1:1 ratio, to undergo either iFR-guided or FFR-guided coronary revascularization. The primary end point was the 1-year risk of major adverse cardiac events, which were a composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization. The trial was designed to show the noninferiority of iFR to FFR, with a margin of 3.4 percentage points for the difference in risk. At 1 year, the primary end point had occurred in 78 of 1148 patients (6.8%) in the iFR group and in 83 of 1182 patients (7.0%) in the FFR group (difference in risk, −0.2 percentage points; 95% confidence interval [CI], −2.3 to 1.8; P<0.001 for noninferiority; hazard ratio, 0.95; 95% CI, 0.68 to 1.33; P=0.78). The risk of each component of the primary end point and of death from cardiovascular or noncardiovascular causes did not differ significantly between the groups. The number of patients who had adverse procedural symptoms and clinical signs was significantly lower in the iFR group than in the FFR group (39 patients [3.1%] vs. 385 patients [30.8%], P<0.001), and the median procedural time was significantly shorter (40.5 minutes vs. 45.0 minutes, P=0.001). Coronary revascularization guided by iFR was noninferior to revascularization guided by FFR with respect to the risk of major adverse cardiac events at 1 year. The rate of adverse procedural signs and symptoms was lower and the procedural time was shorter with iFR than with FFR. (Funded by Philips Volcano; DEFINE-FLAIR ClinicalTrials.gov number, NCT02053038.)

Background— Sirolimus-eluting stents have been reported to be effective in the treatment of coronary bifurcations. Still, it has not been fully clarified which strategy would provide the best results with true bifurcation lesions. Methods and Results— The CACTUS trial (Coronary bifurcations: Application of the Crushing Technique Using Sirolimus-eluting stents) is a prospective, randomized, multicenter study comparing 2 different techniques of stenting, with mandatory final kissing-balloon inflation, in true bifurcations: (1) elective “crush” stenting and (2) stenting of only the main branch, with provisional side-branch T-stenting. From August 2004 to June 2007, 350 patients were enrolled in 12 European centers. The primary angiographic end point was the in-segment restenosis rate, and the primary clinical end point was the occurrence of major adverse cardiac events (cardiac death, myocardial infarction, or target-vessel revascularization) at 6 months. At 6 months, angiographic restenosis rates were not different between the crush group (4.6% and 13.2% in the main branch and side branch, respectively) and the provisional stenting group (6.7% and 14.7% in the main branch and side branch, respectively; P =NS). Additional stenting on the side branch in the provisional stenting group was required in 31% of lesions. Rates of major adverse cardiac events were also similar in the 2 groups (15.8% in the crush group versus 15% in the provisional stenting group, P =NS). Conclusions— In most bifurcations with a significant stenosis in both branches, a provisional strategy of stenting the main branch only is effective, with the need to implant a second stent on the side branch occurring in approximately one third of cases. The implantation of 2 stents does not appear to be associated with a higher incidence of adverse events at 6 months.

The success of a primary percutaneous intervention (PCI) in the setting of ST elevation myocardial infarction depends on the functional and structural integrity of coronary microcirculation. Coronary microvascular dysfunction and obstruction (CMVO) occurs in up to half of patients submitted to apparently successful primary PCI and is associated to a much worse outcome. The current review summarizes the complex mechanisms responsible for CMVO, including pre-existing coronary microvascular dysfunction, and highlights the current limitations in the assessment of microvascular function. More importantly, at the light of the substantial failure of trials hitherto published on the treatment of CMVO, this review proposes a novel integrated therapeutic approach, which should overcome the limitations of previous studies.

Myocardial infarction (MI) with no obstructive coronary atherosclerosis (MINOCA) is a syndrome with different causes. Its prevalence ranges between 5 and 25% of all MIs. The prognosis is extremely variable, depending on the causes of MINOCA. Clinical history, echocardiography, coronary angiography, and left ventriculography represent the first-level diagnostic investigations. Nevertheless, additional tests are required in order to establish its specific cause, thus allowing an appropriate risk stratification and treatment. We review pathogenesis, diagnosis, prognosis, and therapy of MINOCA and propose an algorithm for its management.