Comparison between non-invasive coronary flow reserve and fractional flow reserve to assess the functional significance of left anterior descending artery stenosis of intermediate severity.

BACKGROUND: Assessment of the functional significance of left anterior descending coronary artery (LAD) stenosis of intermediate severity (50%-70% diameter stenosis) is challenging. The aim of this study was to compare the value of noninvasive coronary flow reserve (CFR) with that of invasive fractional flow reserve (FFR) in the setting of LAD stenosis of angiographic intermediate severity. METHODS: Fifty stable consecutive patients (mean age, 63 ± 13 years; 11 women; mean left ventricular ejection fraction, 61 ± 10%) with angiographic proximal LAD stenoses of intermediate severity (55.5 ± 5% diameter stenosis on quantitative coronary angiography), no previous anterior myocardial infarction, and various vascular risk factors were prospectively studied. They underwent FFR assessment with intracoronary bolus adenosine (150 µg), and CFR assessment using intravenous adenosine (140 µg/kg/min over 2 min) in the distal part of the LAD on the same day in nearly all patients. CFR was defined as hyperemic peak diastolic LAD flow velocity divided by baseline flow velocity (normal value >2), and FFR was defined as distal pressure divided by mean aortic pressure during maximal hyperemia (normal value >0.8). RESULTS: The mean FFR and CFR were 0.84 ± 0.07 and 2.7 ± 0.75, respectively, in the whole population. Concordant results between FFR and CFR were seen in 44 patients (88%) and discordant results in six patients (12%). There was a significant correlation between CFR and FFR (r = 0.59, P < .01). A better correlation was found between FFR and percentage LAD diameter stenosis, and lesion length (all P values < .05), than between CFR and the same anatomic markers of stenosis severity (all P values = NS). The sensitivity, specificity, and positive and negative predictive values of CFR >2 to detect a nonsignificant lesion defined by normal FFR were 95%, 69%, 90%, and 82%, respectively. CONCLUSIONS: In patients with LAD stenosis of intermediate severity, discordant results between noninvasive CFR and FFR were not unusual, and the anatomic determinants of the stenosis were better correlated to FFR than to CFR. However, CFR, which is a global evaluation of the coronary tree, has very high sensitivity to detect a nonsignificant lesion, despite the high prevalence of vascular risk factors.

Non-invasive coronary flow reserve after successful primary angioplasty for acute anterior myocardial infarction is an independent predictor of left ventricular adverse remodelling.

AIMS: To assess the usefulness of non-invasive coronary flow reserve (CFR) to predict left ventricular adverse remodelling (LVR) after ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: Sixty-five consecutive patients (mean age 58 +/- 13 years, 24 women) with a first anterior STEMI, underwent prospectively CFR in the distal part of the left anterior descending artery (LAD), using intravenous adenosine infusion (0.14 mg/kg/min, within 2 min), and a standard echocardiography during the same exam, performed within 24 h after successful primary coronary angioplasty, and 6 months later, while the patients were in stable haemodynamic situation. CFR was defined as the peak hyperaemic LAD flow velocity divided by the baseline flow velocity. LV end-systolic volume (ESV) and end-diastolic volume (EDV), and LV ejection fraction (LVEF) were measured using the biplane Simpson's rule. LVR was defined as an absolute increase of ESV > or =15%. Compared with patients without LVR, patients with LVR (n = 18) had higher peak troponin T levels, wall motion score (WMS), a worse initial angiographic TIMI flow grade, and less improved electrocardiographic ST-segment resolution (all P < 0.05), and lower CFR (1.43 +/- 0.2 vs. 1.97 +/- 0.5, P < 0.01). At 6 months, patients with LVR had higher WMS, ESV, EDV, and lower LVEF compared with patients without LVR (all P < 0.01). Furthermore, acute CFR was significantly correlated to the 6-month LVEF and ESV, and to change of LVEF and ESV (all P < 0.01). In the multivariate analysis, acute CFR and initial angiographic TIMI flow grade were the independent predictors of LVR (all P < or = 0.01). Receiver-operating characteristic curve analysis demonstrated that a cut-off value of 1.7 for CFR yields a sensitivity of 100% and a specificity of 62% to predict LVR at follow-up (P < 0.001, area under the curve 0.82). CONCLUSION: Non-invasive CFR is an independent predictor of LVR after successful primary angioplasty of anterior STEMI.

Non-invasive coronary flow reserve after successful primary angioplasty for acute anterior myocardial infarction is an independent predictor of left ventricular recovery and in-hospital cardiac events.

BACKGROUND: The prediction of left ventricular (LV) recovery and adverse cardiac events after reperfused acute myocardial infarction (AMI) is challenging. The aim of this study was to assess the usefulness of noninvasive coronary flow reserve (CFR) to predict LV recovery and in-hospital adverse cardiac events after AMI by comparison with other available tools. METHODS: Fifty-five consecutive patients (mean age, 59 +/- 13 years; 33% women) with first reperfused ST-elevation anterior AMIs and sustained Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow underwent prospectively, < 24 hours after successful primary coronary angioplasty, standard echocardiography and noninvasive CFR assessment in the distal part of the left anterior descending coronary artery, using intravenous adenosine infusion, while in a stable hemodynamic situation. CFR was defined as peak hyperemic left anterior descending coronary artery flow velocity divided by baseline flow velocity. LV ejection fraction (LVEF) was measured using the biplane Simpson's rule. A no-reflow pattern was defined as diastolic deceleration time of basal diastolic coronary flow velocity < 600 ms and/or systolic flow reversal and recovery of LV function as an absolute increase of LVEF >or= 10% at 3-month follow-up. Adverse events were defined as the composite of death, recurrent AMI, and acute heart failure. RESULTS: In the whole population, the mean LVEF was 46 +/- 5% at baseline and 55 +/- 9% at follow-up. Patients without LV recovery had more severely impaired CFR compared with those with LV recovery (2.1 +/- 0.55 vs 1.46 +/- 0.2, P < .001), as did patients with adverse events compared with those without events (P = .01). Furthermore, CFR was significantly correlated with 3-month LVEF and regional wall motion score (both P values < .01). On multivariate analysis, CFR was an independent predictor of global and regional LV function at follow-up (both P values

Prognostic value of transthoracic coronary flow reserve in medically treated patients with proximal left anterior descending artery stenosis of intermediate severity.

AIMS: Prognostic value of transthoracic coronary flow reserve (T-CFR) is not established in patients with left anterior descending artery (LAD) stenosis of intermediate severity. Objective is to determine the prognosis value of T-CFR>2 in medically treated patients with angiographically intermediate [50-70% QCA (quantitative coronary angiography)] proximal LAD stenosis. METHODS AND RESULTS: Among 110 consecutive patients with intermediate LAD stenosis who underwent prospectively T-CFR in the distal part of the LAD after intravenous administration of adenosine to assess the functional significance of the stenosis, 80 patients had T-CFR>2 and were treated medically without revascularization (Group 1). Among the 30 patients who had T-CFR<2, an additional dobutamine stress echocardiography (DSE) was performed: 15 had a negative DSE; were treated medically and served as a comparative group (Group 2), and 15 had a positive DSE; underwent LAD revascularization, and were excluded from further analysis. All patients completed follow-up (16+/-10 months). During the follow-up period (range 6-45 months), 76 patients (95%) remained free of death or LAD-related event in Group 1, vs. 12 patients (80%) in Group 2. By Kaplan-Meier method, at 30 months the per cent estimated survival free from death or target vessel-related events was 92+/-4% in Group 1 and 44+/-22% in Group 2 (P<0.01). By multivariate analysis, T-CFR remained the only independent predictor of death or LAD-related events. CONCLUSION: In patients with proximal LAD stenosis of intermediate severity and T-CFR>2, deferral of revascularization is associated with low event rate.