Background: The decrease in fractional flow reserve (FFR) after adenosine administration from baseline FFR value (termed as Δ FFR) may reflect the compensatory capacity of the microvascular circulation and thus may predict significant coronary stenotic lesions. We aimed to investigate whether baseline FFR and Δ FFR can help identify the coronary ischemic lesion and its severity. Materials and Methods: This cross-sectional study was performed on 154 consecutive patients (Mean age 62. 42 ± 9. 36 years) that underwent coronary angiography and with definitive intermediate coronary lesions at any of the coronary vessels. FFR was calculated by dividing the mean distal intracoronary pressure by the mean arterial pressure. Δ FFR was also defined as the difference between baseline FFR and hyperemic FFR (considering FFR<0. 75 as the criteria for ischemia). Results: The area under receiver-operating characteristic curve for baseline FFR was found as 0. 933, and for Δ FFR was 0. 946 indicated high values of both indices for predicting ischemic lesions. The best cut-off point for baseline FFR and Δ FFR for discriminating ischemic lesions from the normal condition was 89. 5 (yielding a sensitivity of 92. 2% and a specificity of 68. 0%) and 9. 5 (yielding a sensitivity of 96. 0% and a specificity of 85. 3%), respectively. Conclusion: Our study could successfully demonstrate the high value of both baseline FFR and Δ FFR for predicting coronary ischemic lesions with the cut-off values of <89. 5 and >9. 5, respectively.

Background: Fractional flow reserve (FFR) is a gold standard to assess the impact of stenosis on the blood flow. The FFR method enhances diagnostic accuracy, lessens the need for stenting, and reduces costs. However, FFR is used in less than 10% of percutaneous coronary intervention (PCI) procedures because it needs pressure wires to measure the distal and proximal pressures and adenosine to create hyperemic conditions. Pressure-wire-based FFR measurement is, therefore, expensive and invasive. Objective: This study aims to introduce a new approach on the basis of 3D coronary angiography and the Thrombolysis in Myocardial Infarction (TIMI) frame count for fast computation of FFR in patients with coronary artery disease. Material and Methods: In this simulation study, we herein introduce Non-Invasive Flow Ratio drawing upon CFD to measure FFR based on coronary angiography images with less run time. In this study, 3D geometry was created based on coronary angiography images. The mean volumetric flow rate was calculated using the TIMI frame count. FFR calculated based on CFD was compared with pressure-wire-based FFR and NiFR was calculated in 85 patients. Results: The NiFR (r = 0. 738, P< 0. 001) exhibited a strong correlation with pressure-wire-based FFR. The result indicated that FFR was higher than 0. 8 in the arteries with non-significant stenosis and lower than 0. 8 in the arteries with significant stenosis. Conclusion: The computational simulation of FFR and hemodynamic parameters such as pressure drop is a safe, efficient, and cost-effective method to evaluate the severity of coronary stenosis.

Background: The fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) has proven effective in decreasing cardiac events by comparison with all-comers stenting. In this study, we aimed to evaluate the cost-effectiveness of this method in an Iranian population. Methods: In this prospective cohort, patients with moderate stenosis (50%– 70% severity) were included, while those with acute coronary syndrome were excluded. The patients were divided into 2 groups: the FFR group, for whom revascularization was performed based on FFR results, and the control group, for whom revascularization was performed based on the interventionist’ s assessment. An FFR of less than 0. 80 was considered ischemic in this investigation. Results: A total of 188 patients with moderate coronary artery lesions scheduled for elective PCI were included: 98 patients were assigned to the FFR group and 90 to the control group. Readmission and major adverse cardiac events (MACE) were decreased significantly in the FFR group (24. 4% vs 11. 2%; P = 0. 017 and 25. 6% vs 12. 2%; P = 0. 019, respectively). The quality-adjusted life-year (QALY) value was improved in the FFR group in comparison with the control group (0. 8643 ± 0. 0961 vs 0. 7449 ± 0. 10139, respectively; P < 0. 001), resulting in a lower cost for each QALY in the FFR group than in the control group (131 395 349 QALY/rials vs 210 666 667 QALY/rials, respectively; P < 0. 001). Additionally, our calculation of the incremental cost-effectiveness ratio showed that the cost-effectiveness of the FFR utilization was at least 409 million rials and at most 431 million rials for each QALY, depending on the inclusion of the cost of the FFR catheter. Conclusions: Our results demonstrated the effectiveness of FFR in diminishing MACE. The method was cost-effective according to various calculation methods in an Iranian population.

Myocardial fractional flow reserve (FFR) is a new index of the functional significance of intermediate coronary stenoses that is calculated from pressure measurements made during coronary arteriography. The aim of this study was to evaluate the correlation between non-hyperemic coronary pressure dicrotic notch and fractional flow reserve (FFR). A consecutive of 114 patients (73 men and 41 women) was enrolled in this study. Data were shown as means±SD. Statistical analyses were performed with SPSS software. The statistical significance of differences was determined by chi-square analysis with Yates correction. Significance was defined as P<0.05. Positive dicrortic notch was observed in 97 patients (85%). Significant association was detected between coronary pressure notch (dicrotic notch), and FFR as loss of the dicrotic notch was detected in 93.8% (15/16) of patients with FFR less than 0.75 (P=0.001). Upon ROC curve, a cutoff FFR value of approximately 0.75 demonstrated sensivity and specifity of 93.8% and 98%, respectively for loss of the dicrotic notch. The positive predictive value for loss of the dicrotic notch was 88.2%. Our study demonstrated loss of non-hyperemic coronary pressure diacrotic notch correlates significantly with FFR and may predict an FFR<0.75 with high accuracy. In patients with functionally significant coronary stenosis, loss of non-hyperemic diacrotic notch appears to be a useful index of the functional severity of the stenoses and the need for coronary revascularization.

Coronary artery disease is a leading global cause of mortality. It can be diagnosed by fractional flow reserve (FFR) estimation using computed tomography (CT) angiography. This systematic review aims to review the literature about the diagnostic efficacy of FFR estimation using CT scan (FFR-CT) for the diagnosis of coronary artery disease. The dual databases of Medline and Cochrane Central Register of Controlled Trials were searched for relevant literature from their inception till August 15, 2017. The methodological quality was assessed using the Cochrane risk of bias tool. Pooled estimates of specificity and sensitivity were assessed with the corresponding 95% confidence intervals (CI). After careful screening, five studies involving a total of 296 patients were included in the study. For FFR-CT, on meta-analysis of the pooled risk ratio per patient, random-effects model value was 3. 79 (95% CI, 2. 93– 4. 90) and odds ratio per patient was 11. 78 (95% CI, 8. 08– 17. 17). The odds ratio by year to see if heterogeneity is due to sample size was 2. 50 (95% CI, 1. 06– 5. 91). FFR-CT appears to be a reliable and efficacious noninvasive imaging modality, as it demonstrates high accuracy in the determination of anatomy and lesion-specific ischemia, which justifies the performance of additional randomized controlled trials to evaluate the clinical benefits of FFR-CT-guided coronary revascularization...

Percutaneous coronary angioplasty (PTCA) of a coronary stenosis without documented ischemia at noninvasive stress testing is often performed, but its benefit is unproven. Coronary pressure– derived fractional flow reserve (FFR) is an invasive index of stenosis severity defined as the ratio of maximal blood pressure in a stenotic vessel to the normal maximal pressure in the same vessel. FFR is a reliable substitute for noninvasive stress testing and values below 75% identifies stenoses with hemodynamic significance. It is a method that can provide a reliable assessment of coronary stenosis especially in those with intermediate lesions. It can highly impact on decision-making in therapeutic planning and prevent many unnecessary procedures that are routinely done in these cases. In the present study, we report the results of FFR measurements in a series of patients, and this is the first report on the FFR measurement in Iran. The FFR measurement was performed for eleven vessels with intermediate stenosis, and in seven lesions (63.6%) it led to changes in the treatment strategy. On the basis of FFR, percutaneous coronary intervention (PCI) was changed into medical follow-up in five lesions, medical follow-up changed to PCI in one lesion, and coronary artery bypass grafting (CABG) changed to medical follow-up in another.

Background and Aim: Frequency following response (FFR) is a neural response with multiple origins. The purpose of current study is to record FFR with alternative and single polarity 500 Hz tone burst stimuli in the setting of auditory brainstem response (ABR).Methods: The population of this observational study consists of 21 adults (n=42 ears) with a mean age of 22.43 (SD=1.51), with 8 out 21 (38%) being female. The participant shows normal results in otoscopy, tympanometry, acoustic reflex, pure tone audiometry, speech recognition threshold, and speech discrimination score. They underwent ABR with a click and various polarities of 500 Hz tone burst stimuli.Results: First, latencies of ABR waveform with the alternative polarity of click and tone burst were compared and then with changing the polarity to single polarity, FFR was recorded in 24 ears (about 57%) using the 500 Hz tone burst stimuli. The results showed that in some patients changing the polarity caused a better morphology.Conclusion: In some cases, FFR can be recorded in ABR setting. In addition, because of large amplitude, they fade away ABR waveforms.