Background-Discordance between fractional flow reserve (FFR) and coronary flow velocity reserve (CFVR) may reflect important coronary pathophysiology but usually remains unnoticed in clinical practice. We evaluated the physiological basis and clinical outcome associated with FFR/CFVR discordance. Methods and Results-We studied 157 intermediate coronary stenoses in 157 patients, evaluated by FFR and CFVR between April 1997 and September 2006 in which revascularization was deferred. Long-term follow-up was performed to document the occurrence of major adverse cardiac events: cardiac death, myocardial infarction, or target vessel revascularization. Discordance between FFR and CFVR occurred in 31% and 37% of stenoses at the 0.75, and 0.80 FFR cut-off value, respectively, and was characterized by microvascular resistances during basal and hyperemic conditions. Follow-up duration amounted to 11.7 years (Q1-Q3, 9.9-13.3 years). Compared with concordant normal results of FFR and CFVR, a normal FFR with an abnormal CFVR was associated with significantly increased major adverse cardiac events rate throughout 10 years of follow-up, regardless of the FFR cut-off applied. In contrast, an abnormal FFR with a normal CFVR was associated with equivalent clinical outcome compared with concordant normal results: ≤3 years when FFR <0.75 was depicted abnormal and throughout 10 years of follow-up when FFR ≤0.80 was depicted abnormal. Conclusions-Discordance of CFVR with FFR originates from the involvement of the coronary microvasculature. Importantly, the risk for major adverse cardiac events associated with FFR/CFVR discordance is mainly attributable to stenoses where CFVR is abnormal. This emphasizes the requirement of intracoronary flow assessment in addition to coronary pressure for optimal risk stratification in stable coronary artery disease. (Circ Cardiovasc Interv. 2014;7:301-311.)Key Words: coronary flow velocity reserve ◼ coronary microcirculation ◼ fractional flow reserve ◼ stable coronary artery disease

Background— Abnormalities in the coronary microcirculation are increasingly recognized as an elementary component of ischemic heart disease, which can be accurately assessed by coronary flow velocity reserve in reference vessels (refCFVR). We studied the prognostic value of refCFVR for long-term mortality in patients with stable coronary artery disease. Methods and Results— We included patients with stable coronary artery disease who underwent intracoronary physiological evaluation of ≥1 coronary lesion of intermediate severity between April 1997 and September 2006. RefCFVR was assessed if a coronary artery with <30% irregularities was present. RefCFVR >2.7 was considered normal. Patients underwent revascularization of all ischemia-causing lesions. Long-term follow-up was performed to document the occurrence of (cardiac) mortality. RefCFVR was determined in 178 patients. Kaplan–Meier estimates of 12-year all-cause mortality were 16.7% when refCFVR >2.7 and 39.6% when refCFVR ≤2.7 ( P <0.001), whereas Kaplan–Meier estimates for cardiac mortality were 7.7% when refCFVR >2.7 and 31.6% when refCFVR ≤2.7 ( P <0.001). After multivariable adjustment, refCFVR ≤2.7 was associated with a 2.24-fold increase in all-cause mortality hazard (hazard ratio, 2.24; 95% confidence interval, 1.13–4.44; P =0.020) and a 3.32-fold increase in cardiac mortality hazard (hazard ratio, 3.32; 95% confidence interval, 1.27–8.67; P =0.014). Impairment of refCFVR originated from significantly higher baseline flow velocity in the presence of significantly lower reference vessel baseline microvascular resistance ( P <0.001), indicating impaired coronary autoregulation as its cause. Conclusions— In patients with stable coronary artery disease, impaired refCFVR, resulting from increased baseline flow velocity indicating impaired coronary autoregulation, is associated with a significant increase in fatal events at long-term follow-up.

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BackgroundCoronary artery spasm may be the underlying mechanism in up to 10% of cases of acute coronary syndrome (ACS) and sudden cardiac death. Asian individuals exhibit a 3-times greater incidence of spasm than Caucasians; this is likely due to different types of mechanisms. Consequently, solid data is limited about the long-term prognosis in Caucasian patients presenting with ACS and/or out-of-hospital cardiac arrest (OHCA) caused by coronary spasm.MethodsBetween 2002 and 2015, thirty Caucasian patients with coronary artery spasm presenting with ACS (N = 29) and/or OHCA (N = 11) were enrolled in this prospective registry. Follow-up, consisting of regular outpatient visits, was conducted with a mean follow-up period of 7.5 ± 3.3 years. Outcomes included presence of stable angina pectoris, recurrence of ACS, occurrence of implantable cardioverter defibrillator (ICD) shocks and death.ResultsThe majority of patients (60%) remained asymptomatic during the entire follow-up period. At the end of the follow-up period only 3 patients still experienced stable angina (10%). Only 2 patients (7%) had a recurrent cardiac event, in which the ICD provided appropriate shock therapy. Half of the patients treated with stenting (N = 6), required re-interventions.ConclusionCoronary spasm with ACS and/or OHCA in a Caucasian patient cohort has a relatively benign prognosis in the majority of patients in long-term follow-up, if treated appropriately with medical therapy. Both the role of ICD in OHCA secondary to coronary spasm, and the efficacy of stenting to treat vasospastic angina, warrant further study in large-sized prospective clinical trials.