Fractional Flow Reserve Assessment Research Articles

Influence of physiological patterns of coronary disease on fractional flow reserve and instantaneous wave-free ratio changes in patients undergoing TAVI

BackgroundInconsistent variations of hyperaemic and resting physiology indexes have been reported between pre- and post-transcatheter aortic valve implantation (TAVI). AimsThis study aimed to evaluate the predominant physiological pattern of coronary artery disease (CAD) in patients with severe aortic stenosis (SAS) undergoing TAVI and assess its impact on fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) variations between pre- and post-TAVI. MethodsPatients with SAS and CAD undergoing FFR and iFR assessment before and after TAVI were included. Vessels were categorized based on FFR and iFR tertiles of change. Longitudinal vessel analysis using Murray's law-based quantitative flow ratio (μFR) was performed. Disease pattern was considered focal with μFR-pullback pressure gradient index (μFR-PPGi) ≥0.78, and local disease severity was stratified by instantaneous μFR gradient per unit length (dμFR/ds) with a value of 0.025/mm. ResultsIn total, 136 vessels (67 patients) were assessed with μFR, having paired pre- and post-TAVI FFR and iFR. μFR-PPGi was 0.73 ± 0.13, with 60.3 % showing diffuse CAD. dμFR/ds was 0.03 ± 0.03/mm, with 27.2 % having a major gradient. Vessels with decreased FFR post-TAVI had lower pre-TAVI FFR and higher dμFR/ds compared to stable or increased FFR vessels. iFR changes were unpredictable; both decreased and increased iFR vessels post-TAVI had lower pre-TAVI FFR and iFR values and showed major dμFR/ds gradients. ConclusionsIn SAS patients undergoing TAVI, diffuse CAD without major gradients was the predominant physiological pattern. Post-TAVI, FFR typically decreased in vessels with major focal gradients, while iFR changes were more unpredictable.

Predictors of percutaneous coronary intervention derived from CCTA in patients with chronic coronary syndrome

Abstract Background To identify anatomical and morphological plaque features predictors of percutaneous coronary intervention (PCI) and create a multiparametric score to increase the predictive yield. Moreover, we assessed the incremental predictive value of FFRCT (Fractional Flow Reserve derived from CCTA) trans-lesion gradient (ΔFFRCT) when integrated into the score. Methods Observational cohort study including patients undergoing CCTA for suspected coronary artery disease, with FFRCT available, referred to invasive coronary angiogram and assessment of fractional flow reserve. Plaque analysis was performed using validated semi-automated software. Logistic regression was performed to identify anatomical and morphological plaque features predictive of PCI. Optimal thresholds were defined by area under the receiver-operating characteristics curve (AUC) analysis. A scoring system was developed in a derivation cohort (70% of the study population) and tested in a validation cohort (30% of patients). Results The overall study population included 340 patients (455 vessels), among which 238 patients (320 vessels) were included in the derivation cohort. At multivariate logistic regression analysis, absence of left main disease, diameter stenosis (DS), non-calcified plaque (NCP) volume, and percent atheroma volume (PAV) were independent predictors of PCI. Optimal thresholds were: DS³50%, volume of NCP>113 mm3 and PAV>17%. A weighted score (CT-PCI Score) ranging from 0 to 11 was obtained. The AUC of the score was 0.80 (95%CI 0.74-0.86). The integration of ΔFFRCT in the CT-PCI score led to a mild albeit not significant increase in the AUC (0.82, 95%CI 0.77-0.87, p=0.328). Conclusions Plaque anatomy and morphology derived from CCTA could aid in identifying patients amenable to PCI.Central IllustrationPredictive accuracy of the CT-PCI score

The usefulness of IVUS and OCT in patients treated with rotational atherectomy

Abstract Background Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been shown to improve clinical outcomes of percutaneous coronary interventions (PCIs) in selected subsets of patients. Purpose To investigate whether the use of OCT or IVUS during PCI with rotational atherectomy (RA-PCI) will increase odds for successful revascularization defined as thrombolysis in myocardial infarction (TIMI) 3 flow. Methods Data were obtained from the national registry of PCIs (ORPKI) maintained by the Association of Cardiovascular Interventions (AISN) of the Polish Cardiac Society. The dataset includes PCIs spanning from January 2014 to December 2021 Results A total of 6,522 RA-PCIs were analyzed, out of which 708 (10.9%) were guided by IVUS and 86 (1.3%) by OCT. The postprocedural TIMI 3 flow was achieved significantly more often in RA-PCIs guided by intravascular imaging (98.7% vs 96.6%, p<0.0001). Multivariable analysis revealed that using of IVUS and OCT was independently associated with an increased chance of achieving postprocedural TIMI 3 flow by 67% (odds ratio (OR), 1.67; 95% confidence interval (CI): 1.40–1.99; p<0.0001) and 66% (OR, 1.66; 95% CI: 1.09–2.54; p=0.02), respectively. Other factors associated with successful revascularization were as follows: previous PCI (OR, 1.72; p<0.0001) and coronary artery bypass grafting (OR, 1.09; p=0.002), hypertension (OR, 1.14; p<0.0001), fractional flow reserve assessment during angiogram (OR, 1.47; p<0.0001), bifurcation PCI (OR, 3.06; p<0.0001), and stent implantation (OR, 19.6, p<0.0001). Conclusions PCIs with rotational atherectomy guided by intravascular imaging modalities (IVUS or OCT) are associated with a higher procedural success rate compared to angio-guided procedures.

Fractional Flow Reserve Implications for Clinical Decision Making in Coronary Artery Disease.

Fractional flow reserve (FFR) is regarded as the gold standard for assessing the functional significance of coronary artery lesions. However, its utilization in clinical practice remains limited. This study aims to determine whether FFR results can influence treatment decisions for coronary artery disease compared to visual assessments of angiographic images. We conducted a retrospective study involving 63 patients diagnosed with either chronic coronary syndrome (n = 39, 61.9%) or acute coronary syndrome (n = 24, 38.1%) who underwent an FFR assessment. Three experienced interventional cardiologists (>300 PCI procedures/year) reevaluated 105 ambiguous coronary lesions in these patients, blinded to the FFR results. The objective was to assess lesion significance and determine the treatment strategy based on a visual angiographic evaluation. The three operators reached concordant agreement (≥two operators) to perform PCI in 60 (57.1%) of the evaluated lesions based on the angiographic assessment. Of these, nine lesions (15%) were deemed functionally non-significant by FFR (FFR > 0.80). Conversely, they agreed to defer PCI in 45 (42.9%) lesions, but 4 lesions (8.9%) were found to be functionally significant (FFR ≤ 0.80) and required a re-evaluation for PCI. Visual-guided decision making by interventional cardiologists shows variability and does not always align with the functional significance of coronary lesions as determined by FFR. Incorporating FFR into routine decision making could enhance treatment accuracy and patient outcomes.

Correlation and consistency between resting full-cycle ratio and fractional flow reserve in assessing coronary artery function in a Chinese real-world cohort with non-ST-segment elevation acute coronary syndrome: a retrospective observational study

ObjectiveThe study aimed to investigate the correlation and consistency between resting full-cycle ratio (RFR) and fractional flow reserve (FFR) in functional assessment of coronary arteries in a Chinese real-world cohort...

Combined assessment of fractional flow reserve, resting full-cycle ratio, and resting ratio of distal coronary to aortic pressure for clinical outcomes

BackgroundFractional flow reserve (FFR) and non-hyperemic indices are invasive standards for evaluating functional significance of coronary stenosis. However, data are limited about outcomes in vessels with concordant and discordant physiological results, particularly with a ratio of distal coronary to aortic pressure (Pd/Pa) at rest. MethodsThis was a single-center, retrospective, observational study. Coronary physiological indices including FFR, resting full-cycle ratio (RFR), and resting Pd/Pa were invasively evaluated in vessels with intermediate coronary artery stenosis. FFR ≤0.80, RFR ≤0.89, and resting Pd/Pa ≤0.92 were considered physiologically positive. Vessels were divided into three groups according to the results of FFR, RFR, and resting Pd/Pa: concordant positive (all positive for FFR, RFR, and resting Pd/Pa), concordant negative (all negative for FFR, RFR, and resting Pd/Pa), and discordant groups. The primary endpoint was target vessel failure (TVF) defined as a composite of cardiac death and target vessel myocardial infarction and unplanned revascularization. ResultsOf 987 vessels included, 311 (31.5 %), 263 (26.6 %), and 413 (41.9 %) were in the concordant positive, discordant, and concordant negative groups. During a median follow-up period of 417 (208–756) days, TVF occurred more frequently in the concordant positive group, followed by the discordant and concordant negative groups (7.7 % vs. 4.6 % vs. 2.4 %, p = 0.004). TVF increasingly accrued during long-term follow-up, while discordant results of RFR and resting Pd/Pa did not result in worse outcomes compared with negative RFR and resting Pd/Pa. ConclusionThe combined assessment of FFR with RFR and resting Pd/Pa stratified TVF risks in vessels with intermediate coronary stenosis.

Sex Differences in Fractional Flow Reserve Utilization.

Background: The literature review shows that female patients are more frequently underdiagnosed or suffer from delayed diagnosis. Recognition of sex-related differences is crucial for implementing strategies to improve cardiovascular outcomes. We aimed to assess sex-related disparities in the frequency of fractional flow reserve (FFR)-guided procedures in patients who underwent angiography and/or percutaneous coronary intervention (PCI). Methods: We have derived the data from the national registry of percutaneous coronary interventions and retrospectively analyzed the data of more than 1.4 million angiography and/or PCI procedures [1,454,121 patients (62.54% men and 37.46% women)] between 2014 and 2022. The logistic regression analysis was conducted to explore whether female sex was associated with FFR utilization. Results: The FFR was performed in 61,305 (4.22%) patients and more frequently in men than women (4.15% vs. 3.45%, p < 0.001). FFR was more frequently assessed in females with acute coronary syndrome than males (27.75% vs. 26.08%, p < 0.001); however, women with chronic coronary syndrome had FFR performed less often than men (72.25% vs. 73.92%, p < 0.001). Females with FFR-guided procedures were older than men (69.07 (±8.87) vs. 65.45 (±9.38) p < 0.001); however. less often had a history of myocardial infarction (MI) (24.79% vs. 36.73%, p < 0.001), CABG (1.62% vs. 2.55%, p < 0.005) or PCI (36.6% vs. 24.79%, p < 0.001) compared to men. Crude comparison has shown that male sex was associated with a higher frequency of FFR assessment (OR = 1.2152-1.2361, p < 0.005). Conclusions: Despite a substantial rise in FFR utilization, adoption in women remains lower than in men. Female sex was found to be an independent negative predictor of FFR use.

The Usefulness of Intravascular Ultrasound and Optical Coherence Tomography in Patients Treated with Rotational Atherectomy: An Analysis Based on a Large National Registry.

Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) have been shown to improve the clinical outcomes of percutaneous coronary interventions (PCIs) in selected subsets of patients. The aim was to investigate whether the use of OCT or IVUS during a PCI with rotational atherectomy (RA-PCI) will increase the odds for successful revascularization, defined as thrombolysis in myocardial infarction (TIMI) 3 flow. Data were obtained from the national registry of PCIs (ORPKI) maintained by the Association of Cardiovascular Interventions (AISN) of the Polish Cardiac Society. The dataset includes PCIs spanning from January 2014 to December 2021. A total of 6522 RA-PCIs were analyzed, out of which 708 (10.9%) were guided by IVUS and 86 (1.3%) by OCT. The postprocedural TIMI 3 flow was achieved significantly more often in RA-PCIs guided by intravascular imaging (98.7% vs. 96.6%, p < 0.0001). Multivariable analysis revealed that using IVUS and OCT was independently associated with an increased chance of achieving postprocedural TIMI 3 flow by 67% (odds ratio (OR), 1.67; 95% confidence interval (CI): 1.40-1.99; p < 0.0001) and 66% (OR, 1.66; 95% CI: 1.09-2.54; p = 0.02), respectively. Other factors associated with successful revascularization were as follows: previous PCI (OR, 1.72; p < 0.0001) and coronary artery bypass grafting (OR, 1.09; p = 0.002), hypertension (OR, 1.14; p < 0.0001), fractional flow reserve assessment during angiogram (OR, 1.47; p < 0.0001), bifurcation PCI (OR, 3.06; p < 0.0001), and stent implantation (OR, 19.6, p < 0.0001). PCIs with rotational atherectomy guided by intravascular imaging modalities (IVUS or OCT) are associated with a higher procedural success rate compared to angio-guided procedures.

Long-Term Outcomes of Fractional Flow Reserve-Guided Percutaneous Coronary Intervention of Moderate Lesions in Patients with Chronic Coronary Syndrome

Background: Fractional flow reserve (FFR) is crucial to evaluating coronary artery stenosis in patients diagnosed with chronic coronary syndrome (CCS). By assessing the severity of stenosis, FFR assists in determining whether percutaneous coronary intervention (PCI) is necessary. Methods: Conducted at Tehran Heart Center from 2013 through 2017, this cohort study involved 52,248 CCS patients who underwent coronary angiography. Among them, 598 symptomatic individuals, despite receiving comprehensive medical treatment, underwent FFR assessment. Subsequently, 225 patients with positive FFR (≤0.80) underwent PCI, while 373 patients received solely medical treatment. The patients were monitored for 3 years to evaluate primary and secondary endpoints. Results: After 3 years, the PCI group demonstrated a lower incidence of the primary composite endpoint, consisting of all-cause mortality, nonfatal myocardial infarction, repeat target vessel/lesion revascularization (TVR/TLR), and coronary artery bypass graft surgery, than the medical treatment group (HR, 0.85; 95% CI, 0.74 to 0.98; P=0.012). Additionally, urgent TVR/TLR significantly decreased in the PCI group (HR, 0.56; 95% CI, 0.42 to 0.74; P&lt;0.001). Conclusion: FFR-guided PCI demonstrated effectiveness in reducing long-term major adverse cardiac events, primarily by lowering the incidence of TVR/TLR. The results emphasize the significance of FFR-guided PCI in addressing stenosis rather than alleviating ischemia.

Prognostic significance of compliance with fractional flow reserve guidance on diverse vessel-related clinical outcomes.

In patients underwent fractional flow reserve (FFR) assessment, a noteworthy proportion of adverse events occur in vessels in which FFR has not been measured. However, the effect of these non-target vessel-related events on the evaluation of FFR-related benefits remains unknown. In this retrospective study, vessels subjected to FFR measurement were grouped as FFR-based approach and non-compliance with FFR based on whether they received FFR-based treatment. Using inverse probability of treatment weighting (IPTW) to account for potential confounding, we investigated the association between compliance with FFR and 5-year target vessel failure (TVF) non-target vessel failure (NTVF) and vessel-oriented composite endpoints (VOCEs). Of the 1,119 vessels, 201 did not receive FFR-based treatment. After IPTW adjustment, a significantly lower hazard of TVF was observed in the FFR-based approach group (HR: 0.56; 95% CI: 0.34-0.92). While, the intergroup difference in hazard of NTVF (HR: 1.02; 95% CI: 0.45-2.31) and VOCEs (HR: 0.69; 95% CI: 0.45-1.05) were nonsignificant. In patients with CAD subjected to FFR, the FFR-based treatment yields a sustained clinical benefit in terms of the risks of target vessel-related events. The dilution of non-target vessel-related events renders the difference favoring the FFR-based approach nonsignificant.

Predictive value of plaque characteristics for identification of lesions causing ischemia

BackgroundFunctional assessment using fractional flow reserve (FFR) and anatomical assessment using optical coherence tomography (OCT) are used in clinical practice for patients with intermediate coronary stenosis. Moreover, coronary computed tomography angiography (CTA) is a common noninvasive imaging technique for evaluating suspected coronary artery disease before being referred for angiography. This study aimed to investigate the association between FFR and plaque characteristics assessed using coronary CTA and OCT for intermediate coronary stenosis. MethodsBased on a prospective multicenter registry, 159 patients having 339 coronary lesions with intermediate stenosis were included. All patients underwent coronary CTA before being referred for coronary angiography, and both FFR measurements and OCT examinations were performed during angiography. A stenotic lesion identified with FFR ≤0.80 was deemed diagnostic of an ischemia-causing lesion. The predictive value of plaque characteristics assessed using coronary CTA and OCT for identifying lesions causing ischemia was analyzed. ResultsStenosis severity and plaque characteristics on coronary CTA and OCT differed between lesions that caused ischemia and those that did not. In multivariate analysis, low attenuation plaque on coronary CTA (odds ratio [OR]=2.78; P=0.038), thrombus (OR=5.13; P=0.042), plaque rupture (OR=3.25; P=0.017), and intimal vasculature on OCT (OR=2.57; P=0.012) were independent predictors of ischemic lesions. Increasing the number of these plaque characteristics offered incremental improvement in predicting the lesions causing ischemia. ConclusionsComprehensive anatomical evaluation of coronary stenosis may provide additional supportive information for predicting the lesions causing ischemia.

The role of intravascular physiological assessment of the significance of coronary involvement in patients with severe aortic stenosis

As technology improves, the number of transcatheter aortic valve implantation (TAVI) procedures performed is steadily increasing. Due to the comparable outcomes with surgical treatment of aortic stenosis, TAVI is increasingly being performed in a group of younger patients. In this connection, there is an increasing need for a reasonable approach to assessing the severity of concomitant coronary lesions. Non-invasive studies in this group of patients have low sensitivity and specificity in identifying significant coronary narrowing. In addition, the use of stress testing is limited by the risks of potential complications due to the severity of patients with critical aortic stenosis. The assessment of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), which has become widespread in isolated coronary heart disease (CAD), in the case of a combination of CAD with aortic stenosis, requires careful study and analysis. The literature review shows that today there are the first results of using the assessment of coronary physiology to determine indications for myocardial revascularization in patients with aortic stenosis. New threshold values of FFR and iFR applicable for patients in this group are considered. The results of literature data indicate the need for large randomized studies to better understand the method capabilities and develop the most optimal approach to the treatment of TAVI candidates with concomitant CAD.

Hemodynamic Insights into Combined Fractional Flow Reserve and Instantaneous Wave-Free Ratio Assessment Through Quantitative [15O]H2O PET Myocardial Perfusion Imaging.

In patients evaluated for obstructive coronary artery disease (CAD), guidelines recommend using either fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR) to guide coronary revascularization decision-making. The hemodynamic significance of lesions with discordant FFR and iFR measurements is debated. This study compared [15O]H2O PET-derived absolute myocardial perfusion between vessels with concordant and discordant FFR and iFR measurements. Methods: We included 197 patients suspected of obstructive CAD who had undergone [15O]H2O PET perfusion imaging and combined FFR/iFR interrogation in 468 vessels. Resting myocardial blood flow (MBF), hyperemic MBF, and coronary flow reserve (CFR) were compared among 4 groups: FFR low/iFR low (n = 79), FFR high/iFR low (n = 22), FFR low/iFR high (n = 22), and FFR high/iFR high (n = 345). Predefined [15O]H2O PET thresholds for ischemia were 2.3 mL·min-1·g-1 or less for hyperemic MBF and 2.5 or less for CFR. Results: Hyperemic MBF was lower in the concordant low (2.09 ± 0.67 mL·min-1·g-1), FFR high/iFR low (2.41 ± 0.80 mL·min-1·g-1), and FFR low/iFR high (2.40 ± 0.69 mL·min-1·g-1) groups compared with the concordant high group (2.91 ± 0.84 mL·min-1·g-1) (P < 0.001, P = 0.004, and P < 0.001, respectively). A lower CFR was observed in the concordant low (2.37 ± 0.76) and FFR high/iFR low (2.64 ± 0.84) groups compared with the concordant high group (3.35 ± 1.07, P < 0.01 for both). However, for vessels with either low FFR or low iFR, quantitative hyperemic MBF and CFR values exceeded the ischemic threshold in 38% and 49%, respectively. In addition, resting MBF exhibited a negative correlation with iFR (P < 0.001) and was associated with FFR low/iFR high discordance compared with concordant low FFR/low iFR measurements, independent of clinical and angiographic characteristics, as well as hyperemic MBF (odds ratio [OR], 0.41; 95% CI, 0.26-0.65; P < 0.001). Conclusion: We found reduced myocardial perfusion in vessels with concordant low and discordant FFR/iFR measurements. However, FFR/iFR combinations often inaccurately classified vessels as either ischemic or nonischemic when compared with hyperemic MBF and CFR. Furthermore, a lower resting MBF was associated with a higher iFR and the occurrence of FFR low/iFR high discordance. Our study showed that although combined FFR/iFR assessment can be useful to estimate the hemodynamic significance of coronary lesions, these pressure-derived indices provide a limited approximation of [15O]H2O PET-derived quantitative myocardial perfusion as the physiologic standard of CAD severity.

A Convolutional-Transformer Model for FFR and iFR Assessment From Coronary Angiography.

The quantification of stenosis severity from X-ray catheter angiography is a challenging task. Indeed, this requires to fully understand the lesion's geometry by analyzing dynamics of the contrast material, only relying on visual observation by clinicians. To support decision making for cardiac intervention, we propose a hybrid CNN-Transformer model for the assessment of angiography-based non-invasive fractional flow-reserve (FFR) and instantaneous wave-free ratio (iFR) of intermediate coronary stenosis. Our approach predicts whether a coronary artery stenosis is hemodynamically significant and provides direct FFR and iFR estimates. This is achieved through a combination of regression and classification branches that forces the model to focus on the cut-off region of FFR (around 0.8 FFR value), which is highly critical for decision-making. We also propose a spatio-temporal factorization mechanisms that redesigns the transformer's self-attention mechanism to capture both local spatial and temporal interactions between vessel geometry, blood flow dynamics, and lesion morphology. The proposed method achieves state-of-the-art performance on a dataset of 778 exams from 389 patients. Unlike existing methods, our approach employs a single angiography view and does not require knowledge of the key frame; supervision at training time is provided by a classification loss (based on a threshold of the FFR/iFR values) and a regression loss for direct estimation. Finally, the analysis of model interpretability and calibration shows that, in spite of the complexity of angiographic imaging data, our method can robustly identify the location of the stenosis and correlate prediction uncertainty to the provided output scores.

Combined Assessment of Fractional Flow Reserve and Coronary Flow Velocity Reserve after Drug-Eluting Stent Implantation

Coronary flow velocity reserve (CFVR) can be measured noninvasively using stress transthoracic Doppler echocardiography (S-TDE). The prognostic significance of S-TDE-derived CFVR after percutaneous coronary intervention (PCI) remains unknown. The aim of this study was to investigate the prognostic value of post-PCI CFVR and its additional efficacy to fractional flow reserve (FFR) in patients undergoing elective PCI. A retrospective study was conducted involving 187 consecutive patients with chronic coronary syndrome who underwent elective PCI guided by FFR for the left anterior descending coronary artery. Pre- and post-PCI wire-based FFR and CFVR assessments of the left anterior descending coronary artery using S-TDE were performed in all patients. The association between post-PCI clinical and physiologic parameters and major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, heart failure, and unplanned remote target vessel revascularization, was evaluated. Three-quarters of patients exhibited CFVR increase after PCI, while all patients showed FFR improvement. During a median follow-up period of 1.5years, MACE occurred in 21 patients (11.2%). Among clinical demographics, patients with MACE had higher levels of N-terminal pro-brain natriuretic peptide compared with those without MACE (median, 615pg/mL [interquartile range, 245-1,500pg/mL] vs 180pg/mL [interquartile range, 70-559pg/mL]; P=.010). Post-PCI S-TDE-derived CFVR was lower in patients with MACE, while post-PCI FFR showed a nonsignificant tendency to be lower in patients with MACE. In a multivariable analysis, higher NT-proBNP (adjusted hazard ratio, 1.33; 95% CI, 1.02-1.74; P=.038), post-PCI CFVR ≤ 2.0 (adjusted hazard ratio, 2.93; 95% CI, 1.16-7.40; P=.023), and post-PCI FFR ≤ 0.82 (adjusted hazard ratio, 3.93; 95% CI, 1.52-10.18; P=.005) were independently associated with MACE. In patients with chronic coronary syndrome who underwent successful elective PCI for left anterior descending coronary artery, the combined assessment of S-TDE-derived post-PCI CFVR and post-PCI FFR provided a significant association with the occurrence of MACE.

Effects of guiding catheter on franctional flow reserve and non-hyperemic pressure ratios for the assessment of coronary artery stenoses

Abstract Aims Non-hyperemic pressure-derived Indexes (NHPI) provide diagnostic efficacy equivalent to fractional flow reserve (FFR) to guide percutaneous coronary interventions. In the Disengage (Determination of Fractional Flow Reserve in Intermediate Coronary Stenosis With Guiding Catheter Disengagement) registry, selective decannulation of the guiding catheter (GC) within the coronary ostium during FFR assessment was associated with a significant overall decrease in FFR, particularly when the stenosis was located in the proximal and middle coronary segments. So far it is unclear what influence the selective cannulation of the catheter in the coronary artery ostium has on the NHPI. This prospective registry aimed to evaluate the influence of GC engagement within the coronary ostium on FFR and NHPI values. Methods and results In the DISENGAGE@Rest (Determination of Fractional Flow Reserve in Intermediate Coronary Stenosis With Guiding Catheter Disengagement) 133 patients with 164 intermediate coronary artery stenoses (40-90%) were enrolled. We evaluated: 1) the impact of GC engagement within the coronary ostium on FFR and NHPI values; 2) implications for clinical decision making; 3) the relationship between coronary physiology indices and study site (proximal, middle and distal coronary segments). Disengagement of GC was associated with a significant decrease in FFR (FFReng, 0.85±0.07 vs. FFRdis, 0.83±0.07; p&amp;lt; .001), Pd/Pa (Pd/Paeng, 0.94±0.05 vs. Pd/Padis, 0.93±0.05; p&amp;lt; .001) and RFR values (RFReng, 0.91±0.07 vs. RFRdis, 0.90±0.07; p= .018). This significant decrease in invasive physiologic indexes was driven by a significant increase in mean Pa value (Pa eng, 93±15 mm Hg vs. Pa dis, 97±15 for FFR; P &amp;lt; .001; Pa eng, 94±15 mm Hg vs Pa dis, 96±15 for Pd/Pa; P &amp;lt; .001 Pa eng, 95±15 mm Hg vs Pa dis, 97±15 for RFR; P &amp;lt; .001), without changes in mean Pd value. In 24 (15%), 12 (7%) and 17 (10%) lesions, FFR, RFR and Pd/Pa values, respectively, shifted below the cut-off point after GC disengagement with changes in clinical decision-making. There was a significant FFR change, but no NHPI, across different segments (ΔFFReng–FFRdis proximal 0.04±0.03 vs. ΔFFReng–FFRdis middle 0.02±0.02 vs. ΔFFReng–FFRdis distal 0.03±0.04; p= .018). Conclusions The results confirm a significant overall decrease in FFR after GC disengagement and extend this to Pd/Pa and RFR. In case of proximal coronary artery disease, GC disengagement should be performed in order not to underestimate the hemodynamic significance of the lesion under examination.

Changes in cardiac electrical biomarker with hyperaemic stress: an experimental perspective

Abstract Background "Cardiac electrical biomarker" (CEB) is a numerical index measured by the Vectraplex ECG (vECG) System with Vectraplex AMI software that measures changes in the cardiac electrical field vectors from dipolar to multipolar during myocardial ischemia. CEB performs well in detecting NSTEMI and STEMI against physician adjudicated diagnosis. Purpose To assess changes in CEB during adenosine stress induced ischaemia. Method Thirty-three patients, in the VECTRA-PCI trial, with normal surface ECG (sECG) had CEB measured before (CEB0), at maximal hyperaemia (CEBh)) and 1-(CEB1), 2-(CEB2) and 3-(CEB3) hours after standard fractional flow reserve (FFR) assessment using intravenous adenosine. vECGs were adjudicated for quality by 2 blinded observers. vECGs with artefacts and arrhythmias were discarded and CEBs from best traces were analysed. Forty-nine individuals with non-cardiac chest pain, without past medical history or risk factors for CAD, on no medications, normal ECGs, normal blood profile acted as controls. CEBs (median, IQR) were compared using appropriate tests. Results FFR was normal (&amp;gt;/=0.80) (nFFR) in 25 and ischaemic (&amp;lt;0.80) (iFFR) in 8 patients. CEB0 in nFFR and iFFR groups were similar to each other (p=0.785) (Fig 1) and to controls (30.0; IQR 17.0-44.0, vs nFFR: p=0.057, vs iFFR: p=0.241). Compared to CEB0, CEBh was higher in nFFR (p=0.014) (Fig 1A) and iFFR (p=0.016) groups (Fig 1B). CEBh in iFFR (126.0; 109.5-216.0) higher than nFFR (44.0; 27.8-104.8), (p=0.039). In nFFR group, CEB1, 2 and 3, though numerically lower, were statistically similar to CEBh and CEB0 (Fig 1A) suggesting quick recovery. In iFFR group CEB1 was similar to and CEB2 and 3 were lower than CEBh (Fig 1B) suggesting a slower recovery of CEB. Both CEBh and change from CEB0 to CEBh (δCEB0-h), but not CEB0, predicted ischaemic FFR with similar accuracy (p=0.570) (Fig 2). CEBh &amp;gt;96 and δCEB0-h &amp;gt;28 had similar sensitivity of 87.5% with specificity of 68% and 80% respectively. Conclusion Obstructive coronary atheroma is associated with higher CEB than non-obstructive atheroma under hyperaemic stress. Both CEBh and δCEB0-h accurately predict ischaemic FFR with higher specificity of δCEB0-h. This is the first study to measure CEB changes with hyperaemic stress in patients with coronary artery disease and could have potential for wider clinical application. Figure 1. Changes in the CEB during and after hyperaemic stress in patients with normal (A) and ischaemic (B) FFR. Figure 2. Area under the ROC curve to determine the diagnostic accuracy of pre-procedural CEB, hyperaemic CEB and change in CEB from baseline to hyperaemia in determining ischaemic FFR.Fig 1. Changes in CEB with stress.Fig 2. CEB for ischaemic FFR

Abstract 11776: Sex Differences in Coronary Artery Disease Characteristics Among Patients With Type 2 Myocardial Infarction: Results From the Prospective DEFINE-Type 2 MI Study

Background: Type 2 Myocardial Infarction (T2MI) is a result of coronary supply and demand imbalance and is associated with a poor prognosis. It is crucial to identify potential sex-based differences in the prevalence and nature of coronary artery disease (CAD) within this specific population. Retrospective analyses are limited by selection bias, unequal proportions of male and female subjects, and lack of angiographic definition. Hypothesis: In patients with T2MI, women and men will have unique characteristics. Aim: To evaluate sex-based differences in presentation, prevalence/characteristics of CAD and clinical management of T2MI. Methods: In a single-center prospective study, patients with strictly adjudicated T2MI underwent coronary computed tomography angiography and Fractional Flow Reserve (FFR CT ) and quantitative plaque assessment was performed. Results: Of 50 study participants enrolled, 50% were women. Women with T2MI were older than men with T2MI (72.2 ± 10.1 vs. 64 ± 11.3 years; p = 0.009) but otherwise had similar baseline characteristics. A broad and similar mix of T2MI precipitants were present among both sexes. Ischemic ST depression was more common in women (64% vs. 32%; p = 0.05) while men were more likely to have T wave inversion (68% vs. 36%; p = 0.05). Women and men had comparable CAC scores (median [Q1, Q3] 152 [45, 762] vs. 234 [56, 422]; p = 0.07). Prevalence of any CAD (100% vs. 84%; p = 0.12), obstructive CAD (28% vs. 24%; p = 1.0), and hemodynamically significant focal stenosis with FFR CT &lt; 0.80 (64% vs. 56%; p = 0.08) were similar between men and women. While total plaque volumes were similar between men and women, women had significantly lower levels of low-attenuation plaque (median [Q1, Q3]: 3 [1,7] vs. 9 [3, 14]; p = 0.03). Men and women did not significantly differ in percentile of plaque burden. Both sexes showed comparable increases in the utilization of aspirin (OR = 0.67; p = 0.53), beta blockers (OR = 0.76; p = 0.71), and statins (OR = 0.22; p = 0.08) by discharge. Conclusions: This prospective study of using FFRCT in T2MI identifies similarities and differences in clinical presentation and CAD characteristics of T2MI in both men and women. These findings may be helpful in improving the identification and management of T2MI.

The importance of baseline fractional flow reserve to detect significant coronary artery stenosis in different patient populations.

Fractional flow reserve (FFR) assessment compares the blood flow on either side of a blockage in the coronary artery and indicates how severe the stenosis is in the artery. Intravenous adenosine is widely used to achieve conditions of stable hyperaemia for the measurement of FR. However, intravenous adenosine affects both systemic and coronary vascular beds differentially. Therefore, FFR has some limitations, such as the side effects of adenosine and the long procedure time. In addition, there are not enough studies on the evaluation of the baseline ratio of distal coronary pressure to aortic pressure (Pd/Pa) according to standard cut-off values in coronary stenosis under special clinical conditions. This study aimed to assess the diagnostic power of the baseline FFR value for critical coronary stenosis and to determine its predictive value in special patient groups. This retrospective study included 158 patients, who were stratified as Q1 (< 0.89), Q2 (0.89-0.92), Q3 (0.93-0.95) and Q4 (> 0.95) based on baseline FFR values. The baseline Pd/Pa value, the change in adenosine FFR and the raw FFR change were recorded. Its predictive value was also calculated for specific patient groups. The threshold value of baseline FFR level for predicting critical stenosis was ≤ 0.92 with a sensitivity of 92.8% and a specificity of 82% (upper limit of Q2 cartilage). Patients with a baseline FFR value ≤ 0.92 had a 58.4-fold greater likelihood of a critical outcome compared with patients with a baseline FFR value > 0.92 (OR: 58.4; 95% CI: 20.3-124.6). In patients with a baseline FFR ≤ 0.92, the Q1 group had a 10.23-fold higher odds of critical stenosis compared with the Q2 group (OR: 10.23; 95% CI: 2.14-48.84). The same values had similar diagnostic power for all specific patient groups. The baseline FFR value could be used to predict critical coronary stenosis in our patients and had similar value for predicting lesion severity in all the subgroups.

Оценка фракционного резерва кровотока при эндоваскулярном лечении пациентов с хроническим коронарным синдромом и многососудистым поражением коронарного русла

To evaluate the impact of fractional flow reserve (FFR) assessment on the choice of the myocardial revascularization strategy in patients with ischemic heart disease and multivessel coronary artery disease and to compare the long-term outcomes of complete functional or anatomical revascularization.