post-PCI Fractional Flow Reserve Research Articles

High-Risk Morphological and Physiological Coronary Disease Attributes as Outcome Markers After Medical Treatment and Revascularization

ObjectivesThis study sought to evaluate the prognostic impact of plaque morphology and coronary physiology on outcomes after medical treatment or percutaneous coronary intervention (PCI). BackgroundAlthough fractional flow reserve (FFR) is currently best practice, morphological characteristics of coronary artery disease also contribute to outcomes. MethodsA total of 872 vessels in 538 patients were evaluated by invasive FFR and coronary computed tomography angiography. High-risk attributes (HRA) were defined as high-risk physiological attribute (invasive FFR ≤0.8) and high-risk morphological attributes including: 1) local plaque burden (minimum lumen area <4 mm2 and plaque burden ≥70%); 2) adverse plaque characteristics ≥2; and 3) global plaque burden (total plaque volume ≥306.5 mm3 and percent atheroma volume ≥32.2%). The primary outcome was the composite of revascularization, myocardial infarction, or cardiac death at 5 years. ResultsThe mean FFR was 0.88 ± 0.08, and PCI was performed in 239 vessels. The primary outcome occurred in 54 vessels (6.2%). All high-risk morphological attributes were associated with the increased risk of adverse outcomes after adjustment for FFR ≤0.8 and demonstrated direct prognostic effect not mediated by FFR ≤0.8. The 5-year event risk proportionally increased as the number of HRA increased (p for trend <0.001) with lower risk in the PCI group than the medical treatment group in vessels with 1 or 2 HRA (9.7% vs. 14.7%), but not in vessels with either 0 or ≥3 HRA. Of the vessels with pre-procedural FFR ≤0.8, ischemia relief by PCI (pre-PCI FFR ≤0.8 and post-PCI FFR >0.8) significantly reduced vessel-oriented composite outcome risk compared with medical treatment alone in vessels with 0 or 1 high-risk morphological attributes (hazard ratio: 0.33; 95% confidence interval: 0.12 to 0.93; p = 0.035), but the risk reduction was attenuated in vessels with ≥2 high-risk morphological attributes. ConclusionsHigh-risk morphological attributes offered additive prognostic value to coronary physiology and may optimize selection of treatment strategies by adding to FFR-based risk predictions (CCTA-FFR Registry for Development of Comprehensive Risk Prediction Model; NCT04037163)

Mismatch between morphological and functional assessment of the length of coronary artery disease

BackgroundMorphological evaluation of coronary lesion length is a paramount step during invasive assessment of coronary artery disease. Likewise, the extent of epicardial pressure losses can be measured using longitudinal vessel interrogation with fractional flow reserve (FFR) pullbacks. We aimed to quantify the mismatch in lesion length between morphological (based on quantitative coronary angiography, QCA, and optical coherence tomography, OCT) and functional evaluations. MethodsThis is a prospective and multicenter study of patients evaluated by QCA, OCT and motorized fractional flow reserve pullbacks (mFFR). The difference in lesion length between the functional and anatomical evaluations was referred to as FAM. Results117 patients (131 vessels) were included. Median lesion length derived from angiography was 16.05 mm [11.40–22.05], from OCT was 28.00 mm [16.63–38.00] and from mFFR 67.12 mm [25.38–91.37]. There was no correlation between QCA and mFFR lesion length (r = 0.124, 95% CI -0.168-0.396, p = 0.390). OCT lesion length did correlate with mFFR (r = 0.469, 95% CI 0.156–0.696, p = 0.004). FAM was strongly associated with the improvement in vessel conductance with percutaneous coronary intervention (PCI), higher mismatch was associated with lower post-PCI FFR. ConclusionsLesion length assessment differs between morphological and functional evaluations. The morphological-functional mismatch in lesion length is frequent, and influences the results of PCI in terms of post-PCI FFR. Integration of the extent of pressure losses provides clinically relevant information that may be useful for clinical decision-making concerning revascularization strategy.

Optimal Prognostication of Patients with Coronary Stenoses in the Pre- and Post-PCI setting: Comments on TARGET FFR and DEFINE-FLOW Trials Presented at TCT Connect 2020

The body of evidence for the use of coronary physiology assessments to guide percutaneous coronary intervention (PCI) has been growing continuously in recent decades. Two studies presented during TCT Connect 2020 added insights into the prognostic value of coronary physiology measurements in pre- and post-PCI settings. The first study, TARGET FFR, assessed whether a post-PCI fractional flow reserve (FFR)-guided incremental optimisation strategy (PIOS) was superior to angiography-guided PCI. The second study, DEFINE-FLOW, assessed the course of stenoses with fractional and coronary flow reserve (FFR+/CFR-) discordance when treated medically. This article summarises the main results from the TARGET FFR and the DEFINE-FLOW trials and puts them into the context of the existing literature.

Agreement of Angiography-Derived and Wire-Based Fractional Flow Reserves in Percutaneous Coronary Intervention.

Background: Coronary angiography-derived fractional flow reserve (caFFR) measurements have shown good correlations and agreement with invasive wire-based fractional flow reserve (FFR) measurements. However, few studies have examined the diagnostic performance of caFFR measurements before and after percutaneous coronary intervention (PCI). This study sought to compare the diagnostic performance of caFFR measurements against wire-based FFR measurements in patients before and after PCI.Methods: Patients who underwent FFR-guided PCI were eligible for the acquisition of caFFR measurements. Offline caFFR measurements were performed by blinded hospital operators in a core laboratory. The primary endpoint was the vessel-oriented composite endpoint (VOCE), defined as a composite of vessel-related cardiovascular death, vessel-related myocardial infarction, and target vessel revascularization.Results: A total of 105 pre-PCI caFFR measurements and 65 post-PCI caFFR measurements were compared against available wire-based FFR measurements. A strong linear correlation was found between wire-based FFR and caFFR measurements (r = 0.77; p < 0.001) before PCI, and caFFR measurements also showed a high correlation (r = 0.82; p < 0.001) with wire-based FFR measurements after PCI. A total of 6 VOCEs were observed in 61 patients during follow-up. Post-PCI FFR values (≤0.82) in the target vessel was the strongest predictor of VOCE [hazard ratio (HR): 5.59; 95% confidence interval (CI): 1.12–27.96; p = 0.036). Similarly, patients with low post-PCI caFFR values (≤0.83) showed an 8-fold higher risk of VOCE than those with high post-PCI caFFR values (>0.83; HR: 8.83; 95% CI: 1.46–53.44; p = 0.017).Conclusion: The study showed that the caFFR measurements were well-correlated and in agreement with invasive wire-based FFR measurements before and after PCI. Similar to wire-based FFR measurements, post-PCI caFFR measurements can be used to identify patients with a higher risk for adverse events associated with PCI.

Impact of Poststenting Fractional Flow Reserve on Long-Term Clinical Outcomes: The FFR-SEARCH Study.

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Prognostic value of pre-revascularization fractional flow reserve mediated by the post-revascularization level: a causal mediation analysis

Abstract Background The prognostic value of pre-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) can depend on that of the post-PCI FFR and their interaction. To correctly interpret the prognostic value of pre-PCI FFR, it is essential to understand to what extent the relationship between pre-PCI FFR and clinical outcome is explained by pre-PCI FFR-related post-PCI FFR. Purpose The aim of this study is to investigate the extent to which post-PCI FFR mediates the relationship between pre-PCI FFR and vessel-related outcomes using a global, multicenter collaboration registry. Methods Patient data from 4 global FFR registries were pooled and 1488 patients with pre-PCI FFR ≤0.80 were analyzed. The primary outcome was target vessel failure (TVF) during 2-years of follow-up. We evaluated the extent to which post-PCI FFR &amp;lt;0.90 mediated the association between pre-PCI FFR &amp;lt;0.75 and TVF employing a causal mediation analysis in a counterfactual framework. Results Among 1488 patients, the mean (standard deviation) age was 63.5 (9.9) years and 78% (1161 patients) were male. The median (IQR) pre-PCI and post-PCI FFR were 0.71 (0.62–0.76) and 0.88 (0.83–0.92), respectively. The direct effect of low pre-PCI FFR (&amp;lt;0.75) on TVF was significantly elevated (OR: 1.81, 95% CI: 1.03–3.18, p=0.038), and was not mediated by post-PCI FFR&amp;lt;0.90 (indirect effect, OR: 1.01, 95% CI: 0.98–1.05, p=0.39). In the model, post-PCI FFR explained only 2.2% of the association between pre-PCI FFR and TVF. The subgroup analysis implicated that the prognostic information of pre-PCI FFR was mainly for diffuse lesions. Conclusions The prognostic information of pre-PCI FFR did not greatly depend on the results of PCI assessed by post-PCI FFR. Pre-PCI FFR, as a prognostic marker, may mainly reflect the global atherosclerotic burden of the artery, not the extent of the modifiable epicardial stenosis, thus providing independent information from post-PCI FFR. Interpretation Funding Acknowledgement Type of funding source: None

Automated Algorithm Using Pre-Intervention Fractional Flow Reserve Pullback Curve to Predict Post-Intervention Physiological Results

This study sought to develop an automated algorithm using pre-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) pullback recordings to predict post-PCI physiological results in the pre-PCI phase. Both FFR and percent FFR increase measured after PCI showed incremental prognostic implications. However, there is no current method to predict post-PCI physiological results using physiological assessment in the pre-PCI phase. An automated algorithm that analyzes instantaneous FFR gradient per unit time (dFFR(t)/dt) was developed from the derivation cohort (n=30). Using dFFR(t)/dt, the pattern of atherosclerotic disease in each patient was classified into 3 groups (major, mixed, and minor FFR gradient groups) in both the internal validation cohort with constant pullback method (n=234) and the external validation cohort with nonstandardized pullback methods (n=252). All patients in the validation cohorts underwent PCI on the basis of pre-PCI FFR≤0.80. Suboptimal post-PCI physiological results were defined as both post-PCI FFR <0.84 and percent FFR increase≤15%. From the derivation cohort, cutoffs of dFFR(t)/dt for major and minor FFR gradient were 0.035/s and 0.015/s, respectively. In validation cohorts, dFFR(t)/dt showed significant correlations with percent FFR increase (R=0.801; p<0.001) and post-PCI FFR (R=0.099; p=0.029). In both the internal and external validation cohorts, the major FFR gradient group showed significantly higher post-PCI FFR and percent FFR increase compared with those in the mixed or minor FFR gradient groups (all p values<0.001). The proportions of suboptimal post-PCI physiological results were significantly different among 3 groups (10.4% vs. 25.8% vs. 45.7% for the major, mixed, and minor FFR gradient groups, respectively; p<0.001) in validation cohorts. Absence of major FFR gradient lesion (odds ratio: 2.435, 95% [CI]: 1.252 to 4.734; p=0.009) and presence of minor FFR gradient lesion (odds ratio: 2.756, 95% confidence interval: 1.629 to 4.664; p<0.001) were independent predictors for suboptimal post-PCI physiological results. The automated algorithm analyzing pre-PCI pullback curve was able to predict post-PCI physiological results. The incidence of suboptimal post-PCI physiological results was significantly different according to algorithm-based classifications in the pre-PCI physiological assessment. (Automated Algorithm Detecting Physiologic Major Stenosis and Its Relationship with Post-PCI Clinical Outcomes [Algorithm-PCI]; NCT04304677).

Prognostic Value of Prerevascularization Fractional Flow Reserve Mediated by the Postrevascularization Level

The prognostic value of pre-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) may be associated with the post-PCI FFR and their interaction. To correctly interpret the prognostic value of pre-PCI FFR, it is essential to understand to what extent the association of pre-PCI FFR with clinical outcomes is explained by post-PCI FFR. To investigate the extent to which post-PCI FFR mediates the association of pre-PCI FFR with vessel-related outcomes using an international, multicenter collaboration registry. This cohort study used pooled patient data from 4 international FFR registries. A total of 1488 patients with pre-PCI FFR of 0.80 or less who underwent elective PCI were included. Data collection was conducted from November 2011 to August 2019, and analysis was conducted from September 2019 to July 2020. The primary outcome was target vessel failure (TVF) during 2 years of follow-up. The extent to which post-PCI FFR of less than 0.90 mediated the association of pre-PCI FFR less than 0.75 (vs pre-PCI FFR of 0.75 or greater) with TVF was evaluated using a mediation analysis in a counterfactual framework. Among 1488 patients, the mean (SD) age was 63.5 (9.9) years and 1161 patients (78.0%) were men. The median (interquartile range) pre-PCI and post-PCI FFR were 0.71 (0.62-0.76) and 0.88 (0.83-0.92), respectively. The direct association of low pre-PCI FFR (ie, <0.75) with TVF was significant (odds ratio, 1.81; 95% CI, 1.03-3.17; P = .04), while the mediation by post-PCI FFR level of less than 0.90 was not (indirect association: odds ratio, 1.03; 95% CI, 0.98-1.09; P = .24). In sensitivity analyses using several pre-PCI cutoffs, the mediations by post-PCI FFR were consistently weak. In this study, the association of pre-PCI FFR with TVF was not significantly mediated by post-PCI FFR. Poor prognosis due to progressed atherosclerosis, represented as low FFR, may not be reversed by successful PCI that increases FFR. Therefore, the prognostic value of pre-PCI FFR may mainly reflect the global atherosclerotic burden, not the extent of the modifiable epicardial stenosis.

Prognostic Impact of Residual Anatomic Disease Burden After Functionally Complete Revascularization.

Prognostic impact of residual anatomic disease burden after functionally complete percutaneous coronary intervention (PCI), defined by post-PCI fractional flow reserve (FFR) >0.80 would be a clinically relevant question. The current study evaluated clinical outcomes at 2 years according to residual Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) score (RSS) in patients who underwent functionally complete revascularization. A total of 1910 patients (2095 revascularized vessels) with post-PCI FFR >0.80 were selected from the International Post-PCI FFR Registry. RSS was defined as the SYNTAX score recalculated after PCI, SYNTAX revascularization index was calculated as 100×(1-RSS/pre-PCI SYNTAX score), and post-PCI FFR was measured after completion of PCI. The primary outcome was target vessel failure (TVF; a composite of cardiac death, target vessel-related myocardial infarction, and clinically driven target vessel revascularization) at 2 years, and risk of TVF was compared according to tertile classification of RSS (0, 1-5, and >5) and post-PCI FFR (≥0.94, 0.87-0.93, and ≤0.86). After PCI, SYNTAX score was changed from 10.0 (Q1-Q3, 7.0-16.0) to 0.0 (Q1-Q3, 0.0-5.0) and FFR changed from 0.70±0.12 to 0.90±0.05. TVF at 2 years occurred in 4.9%, and patients with TVF showed higher pre-PCI SYNTAX score and lower post-PCI FFR than those without. However, there were no significant differences in SYNTAX revascularization index and RSS. The risk of TVF was not different according to tertile of RSS (log-rank P=0.851). Conversely, risk of TVF was different according to tertile of post-PCI FFR (log-rank P=0.009). Multivariable model showed the risk of TVF was significantly associated with post-PCI FFR (hazard ratio, 1.091 [95% CI, 1.032-1.153]; P=0.002) but not with RSS (hazard ratio, 0.969 [95% CI, 0.898-1.045]; P=0.417). Among patients who underwent functionally complete revascularization, residual anatomic disease burden assessed by RSS was not related with occurrence of TVF at 2 years. These results support the importance of functionally complete revascularization rather than angiographic complete revascularization. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT04012281.

Prognostic Implications of Post-Intervention Resting Pd/Pa and Fractional Flow Reserve in Patients With Stent Implantation

ObjectivesThis study sought to investigate the prognostic implications of post–percutaneous coronary intervention (PCI) nonhyperemic pressure ratios compared with that of post-PCI fractional flow reserve (FFR). BackgroundFFR measured after PCI has been shown to possess prognostic implications. However, the prognostic value of post-PCI nonhyperemic pressure ratios has not yet been clarified. MethodsA total of 588 patients who underwent PCI with available both post-PCI FFR and resting distal coronary pressure-to-aortic pressure ratio (Pd/Pa) were analyzed. Post-PCI FFR and Pd/Pa were measured after successful angiographic stent implantation. The primary outcome was target vessel failure (TVF) up to 2 years, defined as a composite of cardiac death, target vessel–related myocardial infarction, and clinically driven target vessel revascularization. Prognosis of patients according to post-PCI Pd/Pa was compared with that of post-PCI FFR. ResultsDespite angiographically successful PCI, 18.5% had post-PCI FFR ≤0.80 and 36.9% showed post-PCI Pd/Pa ≤0.92. In post-PCI Pd/Pa >0.92 group, 93.8% of patients showed post-PCI FFR >0.80. Conversely, 60.4% of patients showed post-PCI FFR >0.80 in post-PCI Pd/Pa ≤0.92 group. Although there was significant difference in TVF according to post-PCI FFR (≤0.80 vs. >0.80: 10.3% vs. 2.5%; p < 0.001) and Pd/Pa (≤0.92 vs. >0.92: 6.2% vs. 2.5%; p = 0.029), the reclassification ability of model for TVF was increased only with post-PCI FFR (net reclassification index 0.627; p = 0.003; integrated discrimination index 0.019; p = 0.015), but not with post-PCI Pd/Pa, compared with model including clinical factors. Compared with patients with post-PCI Pd/Pa >0.92, patients with post-PCI Pd/Pa ≤0.92 and FFR ≤0.80 had significantly higher risk of TVF (10.4% vs. 2.5%; adjusted hazard ratio: 4.204; 95% confidence interval: 1.521 to 11.618; p = 0.006); however, those with post-PCI Pd/Pa ≤0.92 but FFR >0.80 showed similar risk of TVF (3.5% vs. 2.5%; adjusted hazard ratio: 1.327; 95% confidence interval: 0.398 to 4.428; p = 0.645). ConclusionsOver one-half of the patients with abnormal post-PCI Pd/Pa ≤0.92 showed post-PCI FFR >0.80. Compared with post-PCI FFR, post-PCI Pd/Pa showed limited reclassification ability for the occurrence of TVF. Among patients with abnormal post-PCI Pd/Pa, only patients with positive post-PCI FFR showed significantly higher risk of TVF than did those with post-PCI Pd/Pa >0.92. (Prognostic Perspective of Invasive Hyperemic and Non-Hyperemic Physiologic Indices Measured After Percutaneous Coronary Intervention [PERSPECTIVEPCI]; NCT04265443)

Determinants of insufficient improvement in fractional flow reserve following percutaneous coronary intervention

Fractional flow reserve (FFR) has become an increasingly important index for decision making concerning coronary revascularization. It is commonly accepted that significant improvement in FFR following percutaneous coronary intervention (PCI) is associated with better symptomatic relief and a lower event rate. However, in lesions with insufficient FFR improvement, PCI may not improve prognosis. Leading to the observation that the clinical and angiographic characteristics associated with insufficient FFR improvement have not been fully explored. The purpose of this study was to investigate the factors associated with insufficient improvement in FFR. Using our own PCI database, established between January 2014 and December 2018, we identified 220 stable coronary artery lesions, which had been evaluated for both pre- and post-PCI FFR values. All 220 of these lesions were included in this study. The improvement in FFR (ΔFFR) was calculated in each lesion with the lowest quartile of ΔFFR being defined as the lowest ΔFFR group, and the other quartiles being defined as the intermediate-high ΔFFR group. The mean ΔFFR in the lowest and intermediate-high ΔFFR groups was 0.07 ± 0.02 and 0.21 ± 0.11, respectively. In multivariate logistic regression analysis, a short total stent length (10mm increase: OR 0.67, 95% CI 0.47-0.96, P = 0.030), higher pre-PCI FFR (0.1 increase: OR 4.07, 95% CI 1.83-9.06, P = 0.001), in-stent restenosis (ISR) (OR 8.02, 95% CI 1.26-51.09, P = 0.028), myocardial infarction (MI) in the target vessel (OR 6.87, 95% CI 1.19-39.69, P = 0.031) and non-use of intravascular imaging (OR 0.35, 95% CI 0.12-0.99, P = 0.048) were significantly associated with the lowest ΔFFR group. The use of short stents, higher pre-PCI FFR values, ISR, MI in the target vessel, and non-use of intravascular imaging were significantly associated with insufficient FFR improvement. It was conversely suggested that full coverage and adequate dilatation of the lesions under an intravascular imaging guidance might contribute to an improvement in FFR.

Fractional Flow Reserve following Percutaneous Coronary Intervention.

Fractional flow reserve (FFR) is routinely used to determine lesion severity prior to percutaneous coronary intervention (PCI). However, there is an increasing recognition that FFR may also be useful following PCI to identify mechanisms leading to restenosis and the need for repeat revascularization. Post-PCI FFR is associated with the presence and severity of stent under-expansion and may help identify peri-stent-related complications. FFR pullback may also unmask other functionally significant lesions within the target vessel that were not appreciable on angiography. Recent studies have confirmed the prognostic utility of performing routine post-PCI FFR and suggest possible interventional targets that would improve stent durability. In this review, we detail the theoretical basis underlying post-PCI FFR, provide practical tips to facilitate measurement, and discuss the growing evidence supporting its use.

The Clinical Significance of Physiological Assessment of Residual Ischemia After Percutaneous Coronary Intervention.

Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) have emerged as the invasive diagnostic tools of choice for hemodynamic assessment of the severity of CAD (coronary artery disease). We sought to comprehensively review the evidence on the utility of hemodynamic assessment of the coronary stenoses after percutaneous coronary intervention (PCI) using FFR/iFR, mechanisms of positive post-PCI iFR/FFR, and the clinical impact of significant residual ischemia. The evidence on the utility of the post-PCI hemodynamic assessment has accumulated over the last few years. The post hoc analysis from the FAME 1 and FAME 2 data shows that higher post-PCI FFR is associated with better symptomatic improvement and lower event rate with larger increase in delta FFR (∆ FFR: post-PCI FFR - pre-PCI FFR). Unlike pre-PCI FFR, a consensus has not been established on the optimal value of post-PCI FFR, though multiple studies point toward better clinical outcomes with higher post-PCI FFR and larger ∆ FFR. Visual assessment of adequate stent apposition by coronary angiography is insufficient in evaluating for residual ischemia. The hemodynamic evaluation of residual ischemia by post-PCI FFR/iFR yields clinically relevant data and allows for appropriate post PCI optimization.

Quantitative flow reserve virtual stenting and post stenting measurements to predict fractional flow reserve post stenting from the DOCTORS study population

Quantitative flow reserve (QFR) is a computation of fractional flow reserve (FFR) based on angiography without use of a pressure wire. The ability to predict post-PCI FFR using pre-PCI QFR analysis with a virtual PCI and the correlation between post-PCI QFR compared to post-PCI FFR remains unknown. We sought to evaluate the correlations of pre-PCI QFR analysis with virtual PCI called residual QFR and post-PCI QFR compared to post-PCI FFR. From the DOCTORS (Does Optical Coherence Tomography Optimize Results of Stenting) study population; we blindly analyzed residual QFR and post-PCI QFR from angiographies and compared them to post-PCI FFR. Ninety-three post-PCI QFR measurements and 84 pre-PCI residual QFR measurements were compared to post-PCI FFR measurements. Mean post-PCI FFR value of 0.92 ± 0.05 compared to mean residual QFR and compared to mean post-PCI QFR values were 0.93 ± 0.05 for both ( P > 0.05). Correlation coefficients of residual QFR and post-PCI-QFR were respectively 0.68, (95% CI: 0.53–0.78) and 0.79, (95% CI: 0.70–0.86). Residual QFR corresponding to pre-PCI QFR analysis with virtual PCI, and post-PCI QFR analysis, correlated well with post-PCI FFR. Further studies are needed to prospectively validate a QFR-guided PCI strategy.

Changes in Index of Microcirculatory Resistance during PCI in the Left Anterior Descending Coronary Artery in Relation to Total Length of Implanted Stents.

Aim To investigate the relationship between stent length and changes in microvascular resistance during PCI in stable coronary artery disease (CAD). Methods and Results We measured fractional flow reserve (FFR), index of microcirculatory resistance (IMR), and coronary flow reserve (CFR) before and after stenting in 42 consecutive subjects with stable coronary artery undergoing PCI with stent in the LAD. Patients that had very long stent length (38–78 mm) had lower FFR before stenting than patients that had long (23–37 mm) and moderate (12–22 mm) stent length (0.59 (±0.16), 0.70 (±0.12), and 0.75 (±0.07); p=0.002). FFR improved after stenting and more so in subjects with very long stent length compared to long and moderate stent length (0.27 (s.d ± 16), 0.15 (s.d ± 0.12), and 0.12 (s.d ± 0.07); p for interaction = 0.013). Corrected IMR (IMRcorr) increased after stenting in subjects who had very long stent length, whereas IMRcorr was lower after stenting in subjects who had long or moderate stent length (4.6 (s.d. ± 10.7), −1.4 (s.d. ± 9,9), and −4.2 (s.d. ± 7.8); p for interaction = 0.009). Conclusions Changes in IMR during PCI in the LAD in stable CAD seem to be related to total length of stents implanted, possibly influencing post-PCI FFR. Larger studies are needed to confirm the relationship.

P1250Validation of quantitative flow reserve and residual quantitative flow reserve to predict fractional flow reserve post stenting from the DOCTORS study population

Abstract Background Quantitative flow reserve (QFR) is a computation of fractional flow reserve (FFR) based on angiography without use of a pressure wire. The ability to predict post-PCI FFR using residual QFR after virtual stenting (pre-PCI), and using QFR (post-PCI) remains unknown. We sought to evaluate the correlation and diagnosis accuracy of residual QFR and post-PCI QFR to predict post-PCI FFR. Methods From the DOCTORS (Does Optical Coherence Tomography Optimize Results of Stenting) study population, we blindly analyzed the following from angiography, and compared them to post-PCI FFR: pre-PCI residual contrast QFR (cQFR) and fixed QFR (fQFR), and post-PCI cQFR and fQFR. Results 93 post-PCI QFR measurements and 84 residual QFR measurements were compared to post-PCI FFR measurements in 93 patients. Compared to the post-PCI FFR mean value of 0.92±0.05, mean values of residual cQFR, residual fQFR, post-PCI cQFR and post-PCI fQFR were, respectively: 0.94±0.05, 0.93±0.05, 0.93±0.06 and 0.93±0.05 (p values &gt;0.05 for all pairs except for residual cQFR versus FFR (p=0.01)). Pearson correlation coefficients of residual cQFR, residual fQFR, post-PCI cQFR and post-PCI fQFR compared with post-PCI FFR were, respectively: 0.62, (95% CI: 0.46–0.73); 0.61, (95% CI: 0.45–0.73); 0.75, (95% CI: 0.64–0.83) and 0.73, (95% CI: 0.62–0.81). Area under the curves for these indices with a post-PCI FFR cutoff value of 0.90 were, respectively: 0.79, 0.78, 0.85 and 0.84. Conclusions cQFR and fQFR correlated well and had similar diagnostic performance. Pre-PCI QFR analysis with virtual PCI, and post-PCI QFR analysis, correlated well with post-PCI FFR, and had similar diagnostic accuracy. Further studies are needed to prospectively validate a QFR-guided PCI strategy.

P853Guiding myocardial revascularization by computer assisted interpretation of FFR pullback curves: an agreement study with actual standard of care

Abstract Background Guidelines recommend hemodynamic/functional assessment to guide treatment decision making in stable coronary artery disease. A Fractional flow reserve (FFR) motorized pullback allows a reproducible assessment of the distribution of pressure drop generated by coronary artery disease along the vessel and may provide more relevant hemodynamic information than a single distal FFR value. Purpose We aimed to assess the agreement between the revascularization strategy guided by coronary angiogram and a single distal FFR value interpretation (standard of care, SOC), and a treatment recommendation by a fully automated analysis of pullback FFR curves by an in-house developed computer-based algorithm (CBA). Methods Pullback FFR curves were recorded under continuous intra-venous adenosine in patients with intermediate coronary stenosis by using a motorized device working at a speed of 1 mm/s (Volcano R 100) set to grip a pressure wire. A proprietary algorithm (JD, Mathematica v.11) was applied to: 1) assess the distal FFR on the last 5 mm of the curves, 2) discriminate a stepwise from a progressive decrease of FFR, 3) propose a treatment strategy between optimal medical treatment (OMT), PCI (including the number, length(s) and position(s) of the stent) or CABG, 4) evaluate the post PCI expected change in FFR. A concordance analysis between effective and CBA recommended treatment was performed. Only curves with distal FFR ≤0.85 were included into the analysis. If post PCI FFR was recorded, CBA predicted and measured post PCI FFR were compared. Results 50 vessels from 43 patients (75% LAD, 10% Cx, 15% RCA) with a distal FFR of 0.78±0.08 were assessed. A revascularization was performed in 29 vessels (24 PCI, 5 CABG). Post PCI FFR pullback was recorded in 11 vessels. Compared to SOC, a similar proportion of vessels was referred for revascularization by CBA (56 vs. 58% respectively, Chi2 0.041, p NS). Agreement between SOC and CBA, regarding the need of a revascularization, was observed in 76% of cases. Observed Cohen's Kappa coefficient for OMT, PCI or CABG revascularization strategy was 0.48 (CI 95%: 0.26–0.7). A mismatch between SOC and CBA strategy was observed in 30% (n=15) of vessels. A post hoc examination of FFR pullback curves showed that CBA decision might have been appropriate in 80% of these mismatches. Reclassification of treatment strategy by CBA was related to misinterpretation of one single FFR value (40%, n=6), incorrect detection of significant stepwise decrease in FFR (33%, n=5) and incorrect detection of progressive decrease in FFR (7%, n=1) by SOC approach. A mean bias of 0.01 (CI 95% −0.05–0.07) was observed between CBA predicted and measured post PCI FFR. Conclusion CBA recommended treatment differs from SOC treatment in almost 1/3 of vessels. CBA of FFR pullback curves offers new opportunity to guide myocardial revascularization stategy and warrants further prospective evaluation.

Incremental Prognostic Value of Post-Intervention Pd/Pa in Patients Undergoing Ischemia-Driven Percutaneous Coronary Intervention

ObjectivesThis study sought to evaluate the prognostic value of post–percutaneous coronary intervention (PCI) distal coronary pressure to aortic pressure ratio (Pd/Pa) in predicting long-term clinical outcomes and to determine whether Pd/Pa combined with fractional flow reserve (FFR) post-intervention provides additional prognostic information superior to either marker alone. BackgroundPost-PCI FFR has been shown to be a predictor of long-term outcomes in numerous studies. The role of post-PCI resting Pd/Pa has not been previously studied in this setting. MethodsConsecutive patients undergoing PCI who had pre- and post-PCI Pd/Pa and FFR were followed for major adverse cardiovascular events (MACE) including death, myocardial infarction, and target vessel revascularization. ResultsA total of 574 patients were followed for 30 months (25th to 75th percentile 18 to 46 months). Using receiver-operating characteristic curve analysis post-stenting FFR cutoff of ≤0.86 had the best predictive accuracy of MACE (17% vs. 23%; log-rank p = 0.02), whereas post-stenting Pd/Pa ≤0.96 was the best predictor of MACE (15% vs. 24%; log rank p = 0.0006). There was a significant interaction between post-PCI Pd/Pa and FFR on MACE risk such that patients with Pd/Pa ≤0.96 and FFR ≤0.86 had the highest event rate (25%), whereas those with Pd/Pa >0.96 and FFR >0.86 had the lowest event rate (15%), which was not different from patients with Pd/Pa >0.96 and FFR ≤0.86 (17%). In a fully adjusted Cox regression analysis, Pd/Pa was an independent predictor of MACE (hazard ratio: 2.07; 95% confidence interval: 1.3 to 3.3; p = 0.002). ConclusionsPost-PCI resting Pd/Pa is a powerful prognostic tool for MACE prediction. It adds complementary and incremental risk stratification over established factors including post-PCI FFR.

Personalised fractional flow reserve: a novel concept to optimise myocardial revascularisation.

Fractional flow reserve (FFR) represents the percentage reduction in coronary flow relative to a hypothetically normal artery; however, percutaneous coronary intervention (PCI) seldom achieves physiological normality (FFR 1.00), particularly in the context of diffuse disease. In this study we describe a method for calculating the vessel-specific maximal achievable FFR (FFRmax) providing a personalised assessment of what PCI can achieve. FFR measurements were obtained from 71 patients (100 arteries) undergoing angiography. Three-dimensional (3D) coronary anatomy was reconstructed from angiographic images. An ideal intervention, in which all stenoses are removed, was modelled, and the FFRmax calculated. The "personalised" FFR (FFRpers) was calculated as measured FFR/FFRmax. PCI was performed in 52 vessels and post-PCI FFR measured in 50. FFRmax was compared to post-PCI measured FFRs. The mean FFRmax was 0.92 (±0.04). This was on average 0.04 (±0.05) higher than the corresponding post-PCI measured FFR (p<0.001). FFRpers was significantly higher (0.06±0.04) than measured FFR (p<0.001), indicating that FFR overestimates flow restoration achievable with PCI. A patient's maximal achievable FFR can now be determined prior to PCI. This approach provides a more realistic assessment of the physiological benefit of PCI than is implied by baseline FFR and may prevent unnecessary intervention.

Influence of target vessel on prognostic relevance of fractional flow reserve after coronary stenting.

We sought to investigate the influence of the target vessel on the prognostic relevance of fractional flow reserve (FFR) after percutaneous coronary intervention (PCI). A total of 835 patients with available FFR after second-generation drug-eluting stent (DES) implantation were included in this study. The primary outcome was target-vessel failure (TVF), including cardiac death, target vessel-related myocardial infarction, and clinically driven target vessel revascularisation. The target vessel was the left anterior descending artery (LAD) in 603 patients (72.2%) and non-LAD in 232 patients (27.8%). The distribution pattern of post-PCI FFR values was different between the LAD and non-LAD (p<0.001). The optimal cut-off values of post-PCI FFR for predicting TVF were 0.82 and 0.88 in the LAD and non-LAD, respectively. The cumulative incidence of TVF was significantly higher in patients with lower post-PCI FFR than each cut-off value (10.9% vs. 2.5%, hazard ratio [HR] 4.08, 95% confidence interval [CI]: 2.63-6.34, p<0.001 in LAD; 8.0% vs. 1.9%, HR 6.00, 95% CI: 1.78-20.26, p=0.004 in non-LAD). Higher post-PCI FFR after second-generation DES implantation was associated with better clinical outcomes. Different cut-off values of post-PCI FFR need to be applied according to the target vessel. ClinicalTrials Identifier: NCT01873560.