CCTA based clinical value analysis of ΔCT-FFR in evaluating coronary artery function in patients with severe calcification / 解放军医学杂志

Objective To investigate the clinical value of coronary computed tomography angiography(CCTA)based CT derived fractional flow reserve(CT-FFR)and ΔCT-FFR in improving the diagnostic efficiency for coronary abnormal hemodynamics in patients with severe calcification.Methods We retrospectively analyzed the clinical data of coronary artery disease(CAD)patients who underwent CCTA,CT-FFR,invasive coronary angiography(ICA)and FFR during hospitalization from January 2018 to June 2019 in Chinese PLA General Hospital.Severe calcification was defined as coronary artery calcium score(CACS)≥100 on single vessel level.A total of 107 CAD patients with 149 coronary arteries were included in the present study.The enrolled coronary arteries were assigned to CACS≥100 group(n=56)and CACS<100 group(n=93).CT-FFR was performed on the deep FFR platform based on machine learning(ML)algorithms and ΔCT-FFR was defined as CT-FFR difference between proximal and distal to the coronary lesion.The correlation and consistency between CT-FFR and FFR values were analyzed by Pearson and Bland-Altman methods.We attempted to analyze the incremental value of ΔCT-FFR for coronary functional evaluation,especial for coronary arteries with severe calcification,regarding FFR≤0.8 as the diagnostic gold standard.Comparison of receiver operating characteristic curves(ROC)between different diagnostic methods was presented by Delong test.Results Pearson and Bland-Altman analyses showed appreciable correlation(CACS≥100 group,r=0.71,P<0.01;CACS<100 group,r=0.73,P<0.01)and consistency(CACS≥100 group,Mean=-0.01,P=0.25;CACS<100 group,Mean=0,P=0.96)between CT-FFR and FFR values in both groups.FFR(0.80±0.08 vs.0.84±0.09,P=0.004)and CT-FFR(0.81±0.06 vs.0.85±0.06,P<0.001)levels were significant lower in CACS≥100 group than those in CACS<100 group,while ΔCT-FFR(0.14±0.06 vs.0.09±0.06,P<0.001)levels were significant higher in CACS≥100 group.Moreover,the diagnostic efficiency of CT-FFR in CACS≥100 group was inferior to that in CACS<100 group[AUC=0.792(95%CI 0.663-0.889)vs.AUC=0.929(95%CI 0.856-0.972),P=0.04],while it achieved significant improvement after ΔCT-FFR adjustment[AUC=0.876(95%CI 0.760-0.949)vs.AUC=0.792(95%CI 0.663-0.889),P=0.02]and was similar to that in CACS<100 group(P=0.37).Conclusion For coronary arteries with severe calcification,CT-FFR demonstrated significant incremental value in improving the diagnostic efficiency of coronary abnormal hemodynamics after ΔCT-FFR adjustment.

A multicenter study on the prognostic value of SPECT myocardial blood flow quantitative technique in patients with intermediate stenoses of coronary arteries / 中华核医学与分子影像杂志

Objective:To investigate the prognostic value of myocardial flow reserve (MFR) measured by SPECT myocardial blood flow (MBF) quantitative technique in patients with intermediate stenoses of coronary arteries.Methods:From September 2019 to May 2021, patients with intermediate stenoses (50% to 80%) identified by invasive coronary angiography in Fuwai Hospital, Chinese Academy of Medical Sciences, Fuwai Center China Cardiovascular Hospital, and TEDA International Cardiovascular Hospital were prospectively included. All patients underwent a one-day rest/stress SPECT myocardial perfusion imaging (MPI) and SPECT MBF quantification. The radioactivity distribution of each segment of the MPI bullseye polar maps were obtained according to the standard 5-point method to obtain the summed stress score (SSS) and the summed difference score (SDS) to determine the existence of abnormality. ROC curve analysis was used to obtain the optimal prognostic cut-off value for MFR. The primary endpoint was defined as cardiovascular endpoint events. Survival and prognostic analyses were conducted by Kaplan-Meier method and Cox proportional hazard models. The difference of AUCs was analyzed by Delong test.Results:A total of 314 patients (194 males, 120 females; age (59.4±8.6) years) were enrolled. Over a median follow-up duration of 754 (range: 628-914) d, 54 patients had endpoint events. ROC curve showed that the prediction ability of MFR was significantly better than that of conventional MPI (AUCs: 0.713 and 0.512; z=3.76, P<0.001). The optimal prognostic cut-off value for MFR to predict endpoint events in patients with intermediate stenoses was 2.04. Cox multivariate analysis showed that MFR (hazard ratio ( HR)=0.434, 95% CI: 0.282-0.669, P<0.001) was an independent predictor of endpoint events in patients with intermediate stenoses. Kaplan-Meier survival analysis showed that the prevalence of endpoint events in patients with MFR≤2.04 was significantly higher than that in patients with MFR>2.04 (25.4%(43/169) vs 7.6%(11/145); χ2=21.27, P<0.001). Conclusion:The MFR measured by SPECT MBF quantitative technique has an independent predictive value for cardiovascular endpoint events in patients with intermediate stenoses.

Totally arterialized minimally invasive coronary artery bypass grafting under the guidance of coronary artery function: A case report / 中国胸心血管外科临床杂志

@#We reported a 59-year-old male with exertional angina pectoris, and the coronary angiography showed multiple vessel lesions. The initial strategy was coronary artery bypass grafting (CABG). The measurement of quantitative flow ration (QFR) before operation indicated that the posterior descending branch (PD) did not need to be treated. The left circumflex branch (LCX) was small, and the QFR of the left anterior descending branch (LAD) and the first diagonal branch (D1) was<0.8. Therefore, the LAD and D1 were re-vascularized. The operation strategy was changed to on-pump CABG through a small incision, and the final strategy was LIMA-D1-LAD (sequential), fractional flow reserve (FFR) of distal LAD and D1 after CABG were>0.8 by computed tomography FFR. SYNTAX scores after CABG were 20 and the functional SYNTAX scores after CABG were 3, indicating a good prognosis.

Correlation Between RC/HDL-C Ratio and Ct-Derived Fractional Flow Reserve in Coronary Heart Disease Patients with Critical Lesions / 中山大学学报(医学科学版)

ObjectiveTo investigate the effect of remnant cholesterol （RC）/high-density lipoprotein cholesterol （HDL-C） ratio on coronary computed tomography-derived fractional flow reserve （FFRct） in coronary heart disease （CHD） patients with critical lesions. MethodsA retrospective study was done on patients who were admitted to our department and underwent coronary computed tomography angiography （CCTA） from January 1， 2022 to December 31， 2022. All the 304 culprit vessels from the 219 patients with moderate coronary artery stenosis （50%~70%） were divided into FFRct ischemia group （FFRct≤0.8， N=108） and FFRct non-ischemia group （FFRct>0.8， N=111）. Multivariate logistic regression analysis was used to explore the influencing factors of FFRct≤0.8 in CHD patients with critical lesions. Receiver operating characteristic （ROC） curve was drawn to evaluate the predictive value of RC/HDL-C for FFRct≤0.8. Pearson correlation analysis was used to assess whether there was a correlation between RC/HDL-C and FFRct. ResultsThere were significantly more diabetic patients in FFRct ischemia group （P<0.001）. RC/HDL-C ratio， levels of RC， non-HDL-C， APOB， HbA1c and FPG in FFRct ischemic group were significantly increased （P<0.05）. Pearson correlation analysis showed that the RC/HDL-C ratio， levels of RC， Non-HDL-C， TC， TG， LDL-C， HDL-C， LP（a）， HbA1c， and FPG were all significantly negatively correlated with FFRct values （P<0.05）. Univariate logistic regression analysis showed that diabetes mellitus， RC/HDL-C ratio， levels of RC， non-HDL-C， TG， LP（a）， HbA1c and FPG were significantly correlated with FFRct≤0.8 （P<0.05）. Multivariate logistic regression analysis showed that RC/HDL-C ratio was a predictor of FFRct≤0.80 （OR=4.682， 95%CI 1.197~18.316， P<0.05）. ConclusionsRC/HDL-C ratio is independently correlated with FFRct≤0.8 in CHD patients with moderate stenosis and it is a potential indicator for evaluating coronary functional ischemia.

Research progress on image-based calculation of coronary artery fractional flow reserve / 生物医学工程学杂志

Coronary artery fractional flow reserve (FFR) is a critical physiological indicator for assessment of impaired blood flow caused by coronary artery stenosis. The wire-based invasive measurement of blood flow pressure gradient across stenosis is the gold standard for clinical measurement of FFR. However, it has the risk of vascular injury and requires the use of vasodilators, increasing the time and overall cost of interventional examination. Coronary imaging is playing an important role in clinical diagnosis of stenotic lesions, evaluation of severity of lesions, and planning of therapies. In recent years, the computation of FFR based on the physiological information of blood flow obtained from routinely collected coronary image data has become a research focus in this field. This technique reduces the cost of physiological assessment of coronary lesions and the use of pressure wires. It is beneficial to strengthen the physiological guidance in interventional therapy. In order to better understand this emerging technique, this paper highlights its implementation principle and diagnostic performance, analyzes practical problems and current challenges in clinical applications, and discusses possible future development.

Impact of Coronary Plaque on the Precision of Computational Fractional Flow Reserve Derived from CTA / 中山大学学报(医学科学版)

ObjectiveThe fractional flow reserve （FFR） computed from coronary computed tomographic （CT） angiograms makes it possible to noninvasively assess coronary artery disease， but the impact of plaque on FFR derived from computed tomography angiography （CTA） is still unknown. The study used invasive FFR as the reference standard to analyze the impact of plaque on coronary computed tomography angiography （CCTA）-based quantitative flow ratio （CT-QFR）. MethodsThe retrospective study included 108 patients with suspected coronary heart disease （CHD） who underwent both CCTA and FFR within 60 days. CCTA images were analyzed by the software. We obtained the CT-QFR of target vessels， perfomed the quantitative and qualitative analyses on target vascular plaques， including total plaque volume （TPV）， plaque burden， calcified plaque volume （CPV）， fibrous plaque volume （FPV）， lipid plaque volume （LPV）， and the presence or absence of high-risk plaque. ResultsAccording to the difference between CT-QFR and FFR at blood vessel level， 137 target vessels of 108 patients were divided into the overestimated group （difference＞0.03， n＝29）， reference group （-0.03≤difference≤0.03， n＝88） and underestimated group （difference＜-0.03， n＝20）. The underestimated group （14.81mm3） presented higher LPV than overestimated group （1.97mm3， P < 0.05）. There was a negative correlation between LPV and the difference （P＜0.05）. ConclusionsWhen CT-QFR is used to estimate hemodynamics of coronary artery stenosis， the presence of lipid plaque may underestimate the virtual FFR.

The impact of image quality on the diagnostic performance of CT-derived fractional flow reserve / 中华放射学杂志

Objective:To explore the impact of coronary CT angiography (CCTA) image quality and related factors on the diagnostic performance of CT-derived fractional flow reserve (CT-FFR).Methods:Based on the CT-FFR CHINA trial, the prospective multicenter trial enrolled patients with suspected coronary artery disease who underwent CCTA, CT-FFR and FFR measurement. The subjective and objective assessments of CCTA image were performed on a per-vessel level. The objective assessments included the enhancement degree of coronary artery, the signal-to-noise ratio (SNR) of the aortic root. We used χ 2 test and DeLong test to compare the diagnostic performance of CT-FFR with FFR as the reference standard in different subjective groups (non-artifact vs. artifact), enhancement degree of coronary artery groups (≤400 vs. 401-500 vs.>500 HU), SNR of the aortic root groups (≤16.9 vs.>16.9), body mass index (BMI) groups (<25 kg/m 2 vs.≥25 kg/m 2) and heart rate groups (<75 bpm vs.≥75 bpm). FFR and CT-FFR values≤0.80 was identified as myocardial ischemia. Results:The study enrolled 317 patients with 366 vessels. All target vessels in CCTA images were successfully analyzed by CT-FFR. The accuracy, sensitivity, specificity, positive predictive value, negative predictive value and AUC of the non-artifact group were 90.45%, 86.75%, 93.10%, 90.00%, 90.76% and 0.928, respectively, and those of the artifact group were 83.23%, 87.21%, 79.01%, 81.52%, 85.33% and 0.869, respectively. The differences in accuracy and specificity were statistically significant (χ 2=4.23, P=0.040; χ 2=8.55, P=0.003). The diagnostic efficacy of CT-FFR had no statistically significant differences among different objective groups (all P>0.05). Conclusions:The artifact of CCTA image has an effect on CT-FFR in the diagnosis of myocardial ischemia. The degree of vascular enhancement, SNR, BMI, and heart rate have no significant effect on the diagnostic performance of CT-FFR.

Relationship between coronary flow reserve by CZT SPECT and invasive coronary fractional flow reserve and its potential clinical value / 中华核医学与分子影像杂志

Objective:To evaluate the relationship between regional coronary flow reserve (CFR) obtained from cadmium-zinc-telluride SPECT(CZT SPECT) myocardial functional perfusion imaging (MFPI) and invasive fractional flow reserve (FFR) measured during coronary angiography (CAG) and its clinical value in guiding coronary interventions.Methods:Forty-two patients (30 males, 12 females, age (63.3±9.8) years) who completed CZT SPECT MFPI in the First Affiliated Hospital of Nanjing Medical University from June 2022 to September 2022 and underwent CAG within 3 months were included retrospectively. The concordance of CFR and FFR for diagnosing myocardial ischemia (CFR<2.0 and FFR<0.8) was calculated at the vascular level. The diagnostic efficacy of coronary stenosis≥70% for decreased myocardial blood flow (CFR<2.0) was calculated. Kappa test was used to analyze the data. Results:A total of 126 major coronary arteries were identified in 42 patients, of which 30(23.8%) had a CFR<2.0 by CZT SPECT and 33(26.2%) had stenosis≥70% in CAG. A total of 32 coronary vessels were performed with MFPI CFR and FFR measurements, of which 6 were both decreased and 21 were both normal, so the concordance rate was 84.4%(27/32)( Kappa=0.612, P<0.001). Among 33 coronary vessels with stenosis≥70%, 13 were with CFR≥2.0. Among 30 coronary vessels with CFR<2.0, 10 were with stenosis<70%. When using stenosis≥70% to diagnose CFR decreasing, the sensitivity was 66.7%(20/30), specificity was 86.5%(83/96), positive predictive value was 60.6%(20/33), negative predictive value was 89.2%(83/93), and accuracy was 81.7%(103/126). Conclusions:The concordance between CFR and FFR for the diagnosis of myocardial ischemia is good. Nearly 1/3 of the coronary arteries with decreased CFR have stenosis<70%, whereas nearly 40% of the coronary arteries with stenosis≥70% are not result in myocardial ischemia. Regional CFR determined by CZT SPECT may have potentially significant clinical value in the diagnosis of coronary artery disease and decision-making of coronary intervention.

Value of SPECT myocardial perfusion imaging and coronary flow reserve combined with coronary artery calcium score in the diagnosis of obstructive coronary artery disease / 中华核医学与分子影像杂志

Objective:To study the value of myocardial perfusion imaging (MPI) and coronary flow reserve (CFR) combined with coronary artery calcium score (CACS) in the diagnosis of obstructive coronary artery disease (CAD).Methods:From January 2019 to December 2020, 96 confirmed or suspective CAD patients (65 males, 31 females; age: 30-81 years) who completed rest/stress MPI, CFR and CACS defection in Fuwai Central China Cardiovascular Hospital were retrospectively analyzed. Coronary angiography (CAG) was used as the diagnostic standard to calculate the sensitivity and accuracy of MPI, CFR and MPI/CFR combined with CACS in the diagnosis of CAD. The χ2 test was used to compare the diagnostic efficiency of different methods. Results:The diagnostic sensitivity of MPI was 76.06%(54/71), and the accuracy was 75.00%(72/96), while the sensitivity increased to 97.18%(69/71; χ2=13.67, P<0.001) and the accuracy increased to 87.50%(84/96; χ2=4.92, P=0.020) with significant differences after combined with CACS. The sensitivity and accuracy of CFR were 91.55%(65/71)and 87.50%(84/96), which increased to 97.18%(69/71; χ2=2.12, P=0.137) and 89.58%(86/96; χ2=0.21, P=0.411) with no significant differences after combined with CACS. The sensitivity of MPI in the diagnosis of three-vessel CAD was 70.00%(21/30), which increased to 100%(30/30; χ2=7.75, P=0.004) after combined with CACS; while the sensitivity of MPI combined with CACS in the diagnosis of single-vessel and double-vessel CAD were not significantly improved ( χ2 values: 3.29, 1.51, P values: 0.114, 0.416). Conclusion:The combination of MPI and CACS can significantly improve the diagnostic efficiency of CAD, contributed by the improvement of the diagnostic sensitivity in three-vessel disease; whereas the diagnostic efficiency of CFR for CAD is not significantly improved after combined with CACS.

Quantitative assessment of right ventricular myocardial blood flow with SPECT in pulmonary hypertension animal models / 中华核医学与分子影像杂志

Objective:To explore the changes of right ventricular myocardial perfusion in pulmonary arterial hypertension (PAH) pig models with a quantitative analysis technique based on dynamic SPECT myocardial perfusion imaging, and analyze the relationship between myocardial blood flow, hemodynamics and right ventricular function.Methods:Eleven Chinese miniature pigs (all males, 6-8 months old) weighing 25-30 kg were selected. The PAH models were established by ligating the main pulmonary artery and embolizing the right lower pulmonary artery. After the models were established, dynamic myocardial perfusion imaging with one-day resting/adenosine stress 99Tc m-methoxyisobutylisonitrile (MIBI) SPECT was performed, and the quantitative parameters of left and right ventricles were obtained, including stress myocardial blood flow (SMBF), rest myocardial blood flow (RMBF) and myocardial flow reserve (MFR: the ratio of stress to rest myocardial blood flow). Right heart catheterization was performed to evaluate the mean pulmonary arterial pressure (mPAP), and the right heart function index tricuspid annular plane systolic excursion (TAPSE) was measured by transthoracic echocardiography. According to TAPSE, animals were divided into right heart function preserved group ( n=5, TAPSE≥17 mm) and right heart dysfunction group ( n=4, TAPSE<17 mm). Pearson correlation analysis and the independent-sample t test were used for data analysis. Results:Nine experimental pig models were established with increased mPAP of (38.1 ± 11.6 ) mmHg (1 mmHg=0.133 kPa). Myocardial perfusion imaging showed clear radiotracer uptake in the right heart and myocardial hypertrophy. There was a significant positive correlation between right ventricular myocardial RMBF ((0.71±0.13) ml·min -1·g -1) and mPAP ( r=0.94, P< 0.001). The SMBF in the decreased right ventricular function group was significantly lower than that in the preserved right ventricular function group ((1.66±0.35) vs (2.24±0.30) ml·min -1·g -1;t=2.68, P=0.032). Conclusion:SPECT myocardial blood flow quantification can be used to evaluate the right ventricular myocardial blood flow in pig models of PAH.

Diagnostic value of subtraction based coronary CT fractional flow reserve for calcification-related hemodynamically significant stenosis / 中华老年心脑血管病杂志

Objective To investigate the diagnostic value of subtraction technique based coronary CT fractional flow reserve(CT-FFR)in detecting calcification-related hemodynamically signifi-cant stenosis.Methods A total of 22 patients(42 lesions)with known or suspected coronary ar-tery disease admitted in our hospital from March 2020 to March 2022 were recruited prospectively.Subtraction coronary computed tomography angiography(CCTA)was provided for the patients who were scheduled for invasive coronary angiography(ICA).CCTA image reconstruction algo-rithm was based on hybrid iterative reconstruction.FFR was detected in the patients with moder-ate-to-severe coronary stenosis caused by calcification.A FFR value ≤0.80 was defined as signifi-cant hemodynamic stenosis.With FFR as the reference standard,the diagnostic performance of CCTA,subtraction CCTA,CT-FFR,and subtraction CT-FFR in detecting calcification-related hemodynamically significant stenosis were evaluated.Results Lesion-based analysis showed that subtraction CT-FFR yielded the highest diagnostic performance among four groups of images,with a sensitivity,specificity,positive predictive value,negative predictive value and accuracy of 100.0％,62.1％,54.2％,100.0％and 73.8％,respectively,and an AUC value of 0.83.Patient-based analysis showed subtraction CT-FFR performed best in diagnostic performance,with a sensitivity,specificity,positive predictive value,negative predictive value and accuracy of 100.0％,33.3％,55.6％,100.0％and 63.6％,respectively,and an AUC value of 0.77.Conclusion Subtraction CT-FFR has the highest diagnostic performance for calcification-related hemodynamically signifi-cant stenosis,which expands the application of CT-FFR in severe calcification lesions,and is of good value in clinical application.

Long-term prognostic value of coronary CT angiography-derived fractional flow reserve in elderly patients with CHD / 中华老年心脑血管病杂志

Objective To evaluate the long-term prognostic value of coronary CT angiography-derived fractional flow reserve(CT-FFR)in elderly patients with coronary heart disease(CHD).Methods A retrospective analysis was performed on 1133 patients with clinically suspected CHD from a prospective observational study based on coronary CTA and CT-FFR at the General Hos-pital of Eastern Theater from April 2018 to March 2019,and 330 elderly CHD patients were even-tually included.According to major adverse cardiovascular events(MACE)occurred or not,295 patients were assigned into non-MACE group and 35 patients into the MACE group.Based on cor-onary CTA data,plaque features were analyzed and CT-FFR values were measured in all lesioned vessels.The relationship of plaque features and CT-FFR with MACE was evaluated by using Cox proportional risk regression model,Kaplan-Meier survival curve,and ROC curve analyses.Results The patients with coronary stenosis(≥50％)or CT-FFR value ≤0.8 had a higher risk of MACE(P＜0.01).Univariate Cox analysis showed that coronary stenosis ≥50％and CT-FFR value 0.8 were risk factors of MACE(P＜0.01).After adjusting confounding factors,multivariate Cox analysis indicated that CT-FFR ≤0.8(HR=17.037,95％CI:5.060-57.358,P=0.000)was only independent predictor for MACE.The risk prediction model based on CT-FFR presented better performance than the model based on coronary CTA stenosis(C-index:0.820 vs 0.696,P=0.000).Conclusion CT-FFR≤0.8 is an important independent predictor for long-term MACE in elderly CHD patients.Clinical risk stratification based on CT-FFR may optimize prognostic man-agement strategies in these patients.

A study on the first-order interaction of diagnostic performance of coronary CT angiography-derived fractional flow reserve / 中华内科杂志

Objective:To investigate the effect of image quality, degree of stenosis, calcification, and their first-order interactions on diagnostic performance of coronary computed tomography (CT) angiography-derived fractional flow reserve (CT-FFR).Methods:This is a reanalysis of data from a multi-center retrospective cross-sectional study of CT-FFR in China. A total of 522 patients with suspected or known coronary heart disease [mean age: 61.6 (34.0-83.0) years, 71.8% (354/493) were male] from 11 medical centers including the General Hospital of Eastern Theater Command from May 2015 to October 2019 were enrolled. All patients underwent coronary CT angiography (CCTA), CT-FFR, and invasive FFR examination. Subjective image quality scores of target vessels were recorded on CCTA images, and stenosis was visually assessed at the lesion level. Calcification arc and calcification remodeling index (CRI) were recorded for each lesion. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were compared. Two-way analysis of variance was used to analyze the first-order interaction effects of image quality, degree of stenosis, and calcification.Results:A total of 493 patients with 629 lesions with invasive FFR as a reference were included in the study. The overall sensitivity, specificity, and accuracy of CT-FFR were 80.4%, 93.8%, and 88.6%, respectively. The specificity (95.0% vs. 87.3%, χ2=4.11, P=0.043); accuracy (90.1% vs. 81.9%, χ2=6.22, P=0.013); and NPV (89.7% vs. 80.9%, χ2=4.25, P=0.039) of the group with image quality ≥3 was higher than the group with image quality <3. The degree of stenosis affected the sensitivity, PPV, and NPV of CT-FFR and the calcification arc affected the specificity of CT-FFR (all P>0.05). The specificity (95.8% vs. 90.5%, χ2=4.23, P=0.040); accuracy (91.0% vs. 86.1%, χ2=4.01, P=0.045); and NPV (91.1% vs. 83.8%, χ2=5.10, P=0.024) of the group with CRI<1 were higher than that of the group with CRI≥1. In the subgroup of mild and severe stenosis, no calcification, and CRI<1, the accuracy of CT-FFR with image quality ≥3 points were higher than that with image quality <3 points. The accuracy of CT-FFR in the moderate stenosis group was mainly affected by CRI; the accuracy of CT-FFR in the group with CRI<1 was higher than that in the group with CRI≥1 (after Bonferroni correction, P values between groups were statistically significant). Conclusion:Subjective image quality, degree of stenosis, calcification of lesions, and their first-order interactions can all negatively affect the diagnostic performance of CT-FFR.

Prognostic value of age, creatinine, and left ventricular ejection fraction risk score in patients evaluated with fractional flow reserve: a cross-sectional study

SUMMARY OBJECTIVE: In this study, we investigated the relationship between age, creatinine, and left ventricular ejection fraction risk score and the severity of coronary lesions detected by applying fractional flow reserve in the patient group presenting with chronic coronary syndrome. Also, we presented long-term follow-up results in patients whose age, creatinine, and left ventricular ejection fraction score was evaluated by the fractional flow reserve procedure. METHODS: This study was planned retrospectively and in two centers. For this purpose, 114 patients who met the study criteria and who underwent elective fractional flow reserve between January 2014 and January 2019 were included in the study. Age, creatinine, and left ventricular ejection fraction was calculated as age/left ventricular ejection fraction +1 (if estimated glomerular filtration rate<30 mL/min). RESULTS: They were divided into two groups according to the cutoff value of the age, creatinine, and left ventricular ejection fraction score. A total of 76 patients had an age, creatinine, and left ventricular ejection fraction score of ≤1.17 (Group I) and 38 patients had an age, creatinine, and left ventricular ejection fraction score of >1.17 (Group II). The number of patients with severe lesions in fractional flow reserve was significantly higher in Group II compared with Group I (60.5 vs. 32.9%, p=0.005). According to the Kaplan-Meier analysis, a significant increase was observed in major adverse cardiac events and mortality during the follow-up period in the group with a high-risk score (Log Rank: 15.01, p<0.001 and Log Rank: 8.51, p=0.004, respectively). CONCLUSION: In light of the data we obtained from our study, we found a correlation between the severity of the lesion detected in fractional flow reserve and the age, creatinine, and left ventricular ejection fraction scores. In addition, we found that patients with high age, creatinine, and left ventricular ejection fraction scores had higher mortality and major adverse cardiac events rates during follow-up.

Avaliação Prognóstica da Reserva de Fluxo Fracionada em Diferentes Estratos nos Pacientes com Doença Arterial Coronariana / Prognostic Assessment of Fractional Flow Reserve in Different Strata in Patients with Coronary Artery Disease

Resumo Fundamento Existem dados limitados sobre a evolução clínica de lesões coronarianas não tratadas de acordo com sua gravidade funcional no mundo real. Objetivo Este estudo teve como objetivo avaliar os resultados clínicos de até 5 anos em pacientes com lesões revascularizadas com reserva de fluxo fracionada (FFR) ≤ 0,8 e em pacientes com lesões não revascularizadas com FFR > 0,8. Métodos A avaliação pelo FFR foi realizada em 218 pacientes seguidos por até 5 anos. Os participantes foram classificados com base na FFR no grupo isquêmico (≤ 0,8, grupo intervenção, n = 55), no grupo FFR normal-baixa (> 0,8-0,9, n = 91) e no grupo FFR normal-alta (> 0,9, n = 72). O desfecho primário foram eventos cardíacos adversos maiores (ECAMs), um composto de morte, infarto do miocárdio e necessidade de nova revascularização. O nível de significância adotado neste estudo foi alfa = 0,05; deste modo, resultados com valores de p < 0,05 foram considerados estatisticamente significativos. Resultados A maioria dos participantes era do sexo masculino (62,8%) com média de idade de 64,1 anos. Diabetes estava presente em 27%. À angiografia coronariana, a gravidade da estenose avaliada foi de 62%, 56,4% e 54,3% nos grupos isquêmico, FFR normal-baixa e FFR normal-alta, respectivamente (p < 0,05). O período médio de acompanhamento foi de 3,5 anos. A incidência ECAM foi de 25,5%, 13,2% e 11,1%, respectivamente (p = 0,037). Não houve diferença na incidência de ECAM entre os grupos FFR normal-baixa e FFR normal-alta (p = NS). Conclusão Pacientes com FFR indicativa de isquemia apresentaram piores desfechos quando comparados aos dos grupos não isquêmicos. Entre os grupos que apresentaram valores de FFR considerados normal-baixo e normal-alto, não houve diferença na incidência de eventos. Há necessidade de estudos de longo prazo e com grande número de pacientes para melhor avaliar os desfechos cardiovasculares em pacientes portadores de estenose coronariana moderada com valores de FFR entre 0,8 e 1,0.

Abstract Background There are limited real-world data on the clinical course of untreated coronary lesions according to their functional severity. Objective To evaluate the 5-year clinical outcomes of patients with revascularized lesions with fractional flow reserve (FFR) ≤ 0.8 and patients with non-revascularized lesions with FFR > 0.8. Methods The FFR assessment was performed in 218 patients followed for up to 5 years. Participants were classified based on FFR into ischemia group (≤ 0.8, intervention group, n = 55), low-normal FFR group (> 0.8-0.9, n = 91), and high-normal FFR group (> 0.9, n = 72). The primary endpoint was major adverse cardiac events (MACEs), a composite of death, myocardial infarction, and need for repeat revascularization. The significance level was set at 0.05; therefore, results with a p-value < 0.05 were considered statistically significant. Results Most patients were male (62.8%) with a mean age of 64.1 years. Diabetes was present in 27%. On coronary angiography, the severity of stenosis was 62% in the ischemia group, 56.4% in the low-normal FFR group, and 54.3% in the high-normal FFR group (p<0.05). Mean follow-up was 3.5 years. The incidence of MACEs was 25.5%, 13.2%, and 11.1%, respectively (p=0.037). MACE incidence did not differ significantly between the low-normal and high-normal FFR groups. Conclusion Patients with FFR indicative of ischemia had poorer outcomes than those in non-ischemia groups. There was no difference in the incidence of events between the low-normal and high-normal FFR groups. Long-term studies with a large sample size are needed to better assess cardiovascular outcomes in patients with moderate coronary stenosis with FFR values between 0.8 and 1.0.

Índices fisiológicos não hiperêmicos ­ base teórica, aplicações clínicas e limitações / Non-hyperemic pressure ratios ­ theoretical basis, clinical applications, and limitations

A fisiologia coronariana tornou-se o padrão de tratamento para avaliar o significado funcional da doença aterosclerótica coronariana. Ela permite identificar isquemia miocárdica em nível de vaso, discriminar os padrões funcionais da doença aterosclerótica e orientar a necessidade de revascularização; complementar o planejamento da intervenção coronária percutânea e confirmar o sucesso funcional dessa última. Em uma edição anterior do Journal of Transcatheter Interventions, apresentamos uma revisão abrangente sobre o fluxo fracionado de reserva do miocárdio. Apesar do robusto corpo de evidências que apoiam seu uso, a aceitação clínica do fluxo fracionado de reserva é variável e excessivamente baixa em muitas áreas do mundo. O aumento percebido no tempo do procedimento, o uso de agentes hiperêmicos com seus correspondentes custos e desconforto do paciente, e a dificuldade de interpretação dos resultados em determinadas situações anatômicas contribuíram para a adoção limitada do método. A introdução do índice de fluxo instantâneo no período livre de ondas superou a maioria dessas limitações. Apoiada por uma validação técnica sólida e dados de desfechos clínicos, o índice de fluxo instantâneo no período livre de ondas recebeu as mesmas indicações clínicas que o fluxo fracionado de reserva nas recomendações mais recentes das diretrizes. Isso foi seguido pela introdução de outros índices pressóricos não hiperêmicos, já comercialmente disponíveis. Neste artigo, revisamos as bases fisiológicas que justificam o uso de índices pressóricos não hiperêmicos, sua validação técnica e clínica e dados de desfechos clínicos, além de discutirmos suas aplicações em situações anatômicas específicas, com exemplos de casos dos autores, sempre que aplicável.

Coronary physiology has become the standard of care to assess the functional significance of coronary atherosclerotic disease. It allows for identification of myocardial ischemia on a vessel level, discrimination of the functional patterns of atherosclerotic disease, guidance for the need of revascularization, complements the planning of percutaneous coronary intervention and verification of the functional success of percutaneous coronary intervention. On a previous issue of the Journal of Transcatheter Interventions, we presented a comprehensive review about fractional flow reserve. Despite the robust body of evidence supporting its use, the clinical use of fractional flow reserve is variable, and unreasonably low in many areas around the globe. The perceived increase in procedure time, the use of hyperemic agents with its related costs and patient discomfort, and difficulty in interpreting results in certain anatomical scenarios have contributed to the limited adoption of fractional flow reserve. The introduction of instantaneous wave-free ratio overcame most of these limitations. Supported by sound technical validation, and clinical outcomes data, instantaneous wave-free ratio received the same clinical indications as fractional flow reserve in the most recent guidelines recommendations. This was followed by the introduction of other non- hyperemic pressure ratios for commercial use. In the current manuscript we review the physiological basis that supports the use of non-hyperemic pressure ratios, their technical and clinical validation, clinical outcomes data, and discuss its applications on specific anatomic scenarios, with examples of cases from the authors, whenever applicable.

Ajustando a RFR por Preditores de Discordância, "A RFR Ajustada": Uma Metodologia Alternativa para Melhorar a Capacidade Diagnóstica dos Índices Coronarianos / Adjusting RFR by Predictors of Disagreement, "The Adjusted RFR": An Alternative Methodology to Improve the Diagnostic Capacity of Coronary Indices

Resumo Fundamento Os limiares de corte para a "relação do ciclo completo de repouso" (RFR) oscilam em diferentes séries, sugerindo que as características da população podem influenciá-los. Da mesma forma, foram documentados preditores de discordância entre a RFR e a reserva de fluxo fracionado (FFR). O Estudo RECOPA, mostrou que a capacidade diagnóstica está reduzida na "zona cinzenta" da RFR, tornando necessária a realização de FFR para descartar ou confirmar isquemia. Objetivos Determinar os preditores de discordância, integrar as informações que eles fornecem em um índice clínico-fisiológico: a "RFR Ajustada", e comparar sua concordância com o FFR. Métodos Usando dados do Estudo RECOPA, os preditores de discordância em relação à FFR foram determinados na "zona cinzenta" da RFR (0,86 a 0,92) para construir um índice ("RFR Ajustada") que pesaria a RFR juntamente com os preditores de discordância e avaliar sua concordância com a FFR. Resultados Foram avaliadas 156 lesões em 141 pacientes. Os preditores de discordância foram: doença renal crônica, cardiopatia isquêmica prévia, lesões não envolvendo a artéria descendente anterior esquerda e síndrome coronariana aguda. Embora limitada, a "RFR Ajustada" melhorou a capacidade diagnóstica em comparação com a RFR na "zona cinzenta" (AUC-RFR = 0,651 versus AUC-"RFR Ajustada" = 0,749), mostrando também uma melhora em todos os índices diagnósticos quando foram estabelecidos limiares de corte otimizados (sensibilidade: 59% a 68%; especificidade: 62% a 75%; acurácia diagnóstica: 60% a 71%; razão de verossimilhança positiva: 1,51 a 2,34; razão de verossimilhança negativa: 0,64 a 0,37). Conclusões Ajustar a RFR integrando as informações fornecidas pelos preditores de discordância para obter a "RFR Ajustada" melhorou a capacidade diagnóstica em nossa população. Mais estudos são necessários para avaliar se os índices clínico-fisiológicos melhoram a capacidade diagnóstica da RFR ou de outros índices coronarianos.

Abstract Background Cutoff thresholds for the "resting full-cycle ratio" (RFR) oscillate in different series, suggesting that population characteristics may influence them. Likewise, predictors of discordance between the RFR and fractional flow reserve (FFR) have been documented. The RECOPA Study showed that diagnostic capacity is reduced in the RFR "grey zone", requiring the performance of FFR to rule out or confirm ischemia. Objectives To determine predictors of discordance, integrate the information they provide in a clinical-physiological index, the "Adjusted RFR", and compare its agreement with the FFR. Methods Using data from the RECOPA Study, predictors of discordance with respect to FFR were determined in the RFR "grey zone" (0.86 to 0.92) to construct an index ("Adjusted RFR") that would weigh RFR together with predictors of discordance and evaluate its agreement with FFR. Results A total of 156 lesions were evaluated in 141 patients. Predictors of discordance were: chronic kidney disease, previous ischemic heart disease, lesions not involving the anterior descending artery, and acute coronary syndrome. Though limited, the "Adjusted RFR" improved the diagnostic capacity compared to the RFR in the "grey zone" (AUC-RFR = 0.651 versus AUC-"Adjusted RFR" = 0.749), also showing an improvement in all diagnostic indices when optimal cutoff thresholds were established (sensitivity: 59% to 68%; specificity: 62% to 75%; diagnostic accuracy: 60% to 71%; positive likelihood ratio: 1.51 to 2.34; negative likelihood ratio: 0.64 to 0.37). Conclusions Adjusting the RFR by integrating the information provided by predictors of discordance to obtain the "Adjusted RFR" improved the diagnostic capacity in our population. Further studies are required to evaluate whether clinical-physiological indices improve the diagnostic capacity of RFR or other coronary indices.

Fractional flow reserve [FFR] guided stenting of left main coronary artery in acute coronary syndrome: A single centre experience

The present study assesses the clinical outcomes after left main coronary stenting, using clinical evaluation, angiography, and Fractional Flow Reserve (FFR). A prospective observational study was conducted on 72 patients undergoing left main coronary artery (LMCA) stenting, transthoracic echocardiography, coronary angiography, and percutaneous coronary intervention were done and FFR was recorded. At the end of 6 months, follow up check angiography, FFR study were performed. The stent was placed from LMCA to left anterior descending artery (LAD) artery among 45.83% of patients and 9.72% had from LMCA to Left circumflex artery. The mortality rate was 8.33%. The fractional flow reserve was 0.81 on an average ranging from 0.58 to 0.90. Relatively low incidence of major cardiac event was noted among patients with single vessel disease and ostial LMCA disease.

Fluxo fracionado de reserva do miocárdio: bases fisiológicas, aplicações clínicas e limitações / Fractional flow reserve: physiological bases, clinical applications and limitations

A avaliação fisiológica invasiva da circulação coronariana emergiu nos últimos anos como uma abordagem diagnóstica valiosa no manejo de pacientes com síndrome coronariana crônica, contornando limitações importantes como avaliar função a partir da anatomia e a baixa resolução espacial associada à angiografia ou testes não invasivos. O valor das medidas de fluxo hiperêmico para estimar a relevância funcional das estenoses coronárias é suportado por um grande número de estudos. O objetivo do presente artigo é rever as principais bases fisiológicas, aplicações clínicas e limitações do fluxo fracionado de reserva do miocárdio, o principal índice utilizado na avaliação funcional invasiva da circulação coronariana.

Invasive physiological assessment of the coronary circulation has emerged in recent years as a valuable diagnostic approach in the management of patients with chronic coronary syndrome, overcoming important limitations such as evaluating function from the anatomy and the low spatial resolution associated with angiography or non-invasive tests. The value of hyperemic flow measurements to estimate the functional relevance of coronary stenoses is supported by many studies. The aim of this paper is to review the physiological bases, clinical applications and limitations of myocardial fractional flow reserve, the main index used in the invasive functional assessment of the coronary circulation.