Pulse transmission coefficient: a nonhyperemic index for physiologic assessment of procedural success following percutaneous coronary interventions.

Intracoronary pressure measurements and the determination of fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) predict adverse events. Coronary lesions may impair the transmission of pressure waves across a stenosis, potentially acting as a high-frequency filter. The pulse transmission coefficient (PTC) is a nonhyperemic parameter that calculates the transmission of high-frequency components of the pressure signal through a stenosis. It was shown recently that PTC is highly correlated with FFR. This study was designed to examine the change of PTC as compared to FFR following PCI. Pressure signals were obtained by pressure guidewire in 27 lesions pre- and post-PCI and were analyzed with an algorithm that identifies the high-frequency component in the pressure signal. The PTC was calculated at baseline as the ratio between distal and proximal high-frequency components of the pressure waveform across the lesion. FFR measurements were assessed with intracoronary adenosine. There was a significant increase in PTC following PCI (0.15 +/- 0.17 at baseline vs. 0.84 +/- 0.11 post-PCI; P < 0.001). Comparable changes were observed for FFR (0.58 +/- 0.12 at baseline vs. 0.91 +/- 0.05 post-PCI; P < 0.001). PTC is a nonhyperemic parameter for physiologic assessment of coronary artery stenoses. Similar to FFR, PTC is significantly increased following PCI. Thus, it may serve as an adjunct index for the functional assessment of procedural success following PCI.     

Prognostic Implications of Relative Increase and Final Fractional Flow Reserve in Patients With Stent Implantation

Objectives

The study sought to investigate the prognostic implications of relative increase of fractional flow reserve (FFR) with PCI in combination with post–percutaneous coronary intervention (PCI) FFR.

“Virtual” (Computed) Fractional Flow Reserve: Current Challenges and Limitations

Fractional flow reserve (FFR) is the “gold standard” for assessing the physiological significance of coronary artery disease during invasive coronary angiography. FFR-guided percutaneous coronary intervention improves patient outcomes and reduces stent insertion and cost; yet, due to several practical and operator related factors, it is used in <10% of percutaneous coronary intervention procedures. Virtual fractional flow reserve (vFFR) is computed using coronary imaging and computational fluid dynamics modeling. vFFR has emerged as an attractive alternative to invasive FFR by delivering physiological assessment without the factors that limit the invasive technique. vFFR may offer further diagnostic and planning benefits, including virtual pullback and virtual stenting facilities. However, there are key challenges that need to be overcome before vFFR can be translated into routine clinical practice. These span a spectrum of scientific, logistic, commercial, and political areas. The method used to generate 3-dimensional geometric arterial models (segmentation) and selection of appropriate, patient-specific boundary conditions represent the primary scientific limitations. Many conflicting priorities and design features must be carefully considered for vFFR models to be sufficiently accurate, fast, and intuitive for physicians to use. Consistency is needed in how accuracy is defined and reported. Furthermore, appropriate regulatory and industry standards need to be in place, and cohesive approaches to intellectual property management, reimbursement, and clinician training are required. Assuming successful development continues in these key areas, vFFR is likely to become a desirable tool in the functional assessment of coronary artery disease.     

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.     

Clinical Validation of a Virtual Planner for Coronary Interventions Based on Coronary CT Angiography

BackgroundLow fractional flow reserve (FFR) values after percutaneous coronary intervention (PCI) carry a worse prognosis than high post-PCI FFR values. Therefore, the ability to predict post-PCI FFR might play an important role in procedural planning. Post-PCI FFR values can now be computed from pre-PCI coronary computed tomography angiography (CTA) using the fractional flow reserve derived from coronary computed tomography angiography revascularization planner (FFR_CT Planner).ObjectivesThe aim of this study was to validate the accuracy of the FFR_CT Planner.MethodsIn this multicenter, investigator-initiated, prospective study, patients with chronic coronary syndromes and significant lesions based on invasive FFR ≤0.80 were recruited. The FFR_CT Planner was applied to the fractional flow reserve derived from coronary computed tomography angiography (FFR_CT) model, simulating PCI. The primary objective was the agreement between the predicted post-PCI FFR by the FFR_CT Planner and measured post-PCI FFR. Accuracy of the FFR_CT Planner’s luminal dimensions was assessed by using post-PCI optical coherence tomography as the reference.ResultsOverall, 259 patients were screened, with 120 patients (123 vessels) included in the final analysis. The mean patient age was 64 ± 9 years, and 24% had diabetes. Measured FFR post-PCI was 0.88 ± 0.06, and the FFR_CT Planner FFR was 0.86 ± 0.06 (mean difference: 0.02 ± 0.07 FFR unit; limits of agreement: –0.12 to 0.15). Optical coherence tomography minimal stent area was 5.60 ± 2.01 mm², and FFR_CT Planner minimal stent area was 5.0 ± 2.2 mm² (mean difference: 0.66 ± 1.21 mm²; limits of agreement: –1.7 to 3.0). The accuracy and precision of the FFR_CT Planner remained high in cases with focal and diffuse disease and with low and high calcium burden.ConclusionsThe FFR_CT-based technology was accurate and precise for predicting FFR after PCI. (Precise Percutaneous Coronary Intervention Plan Study [P3]; NCT03782688)     

血流储备分数在冠状动脉介入策略选择中的应用价值

血流储备分数是指在存在狭窄病变的情况下,该冠状动脉所提供给心肌区域能获得的最大血流量与同一区域在正常情况下所能获得的最大血流量之比。血流储备分数直接评价受病变影响的血管供血生理功能,它所提供的信息与心肌灌注研究所得相似,但它较后者更为明确且有一个更好的空间分辨率。该指标可广泛应用于冠状动脉各种病变的介入指导,尤其适用于复杂病变如分叉病变和多支弥漫病变,多项研究提示基于血流储备分数的介入治疗具有更好的临床结果。此外,血流储备分数尚可对介入手术的效果及预后进行预测。     

FFR-Guided PCI Optimization Directed by High-Definition IVUS Versus Standard of Care: The FFR REACT Trial

BackgroundPost–percutaneous coronary intervention (PCI) fractional flow reserve (FFR) <0.90 is common and has been related to impaired patient outcome.ObjectivesThe authors sought to evaluate if PCI optimization directed by intravascular ultrasound (IVUS) in patients with post-PCI FFR <0.90 could improve 1-year target vessel failure (TVF) rates.MethodsIn this single-center, randomized, double-blind trial, patients with a post-PCI FFR <0.90 at the time of angiographically successful PCI were randomized to IVUS-guided optimization or the standard of care (control arm). The primary endpoint was TVF (a composite of cardiac death, spontaneous target vessel myocardial infarction, and clinically driven target vessel revascularization) at 1 year.ResultsA total of 291 patients with post-PCI FFR <0.90 were randomized (IVUS-guided optimization arm: n = 145/152 vessels, control arm: n = 146/157 vessels). The mean post-PCI FFR was 0.84 ± 0.05. A total of 104 (68.4%) vessels in the IVUS-guided optimization arm underwent additional optimization including additional stenting (34.9%) or postdilatation only (33.6%), resulting in a mean increase in post-PCI FFR in these vessels from 0.82 ± 0.06 to 0.85 ± 0.05 (P < 0.001) and a post-PCI FFR ≥0.90 in 20% of the vessels. The 1-year TVF rate was comparable between the 2 study arms (IVUS-guided optimization arm: 4.2%, control arm: 4.8%; P = 0.79). There was a trend toward a lower incidence of clinically driven target vessel revascularization in the IVUS-guided optimization arm (0.7% vs. 4.2%, P = 0.06).ConclusionsIVUS-guided post-PCI FFR optimization significantly improved post-PCI FFR. Because of lower-than-expected event rates, post-PCI FFR optimization did not significantly lower TVF at the 1-year follow-up.     

Percutaneous coronary intervention or bypass surgery in multivessel disease? A tailored approach based on coronary pressure measurement

The optimal revascularization strategy, percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG), for patients with multivessel coronary artery disease (MVD) remains controversial. The aim of the present study was to compare the long-term outcomes after selective PCI of only hemodynamically significant lesions (fractional flow reserve, or FFR < 0.75) to CABG of all stenoses in patients with MVD. In 150 patients with MVD referred for CABG, FFR was determined in 381 coronary arteries considered for bypass grafting. If the FFR was less than 0.75 in three vessels or in two vessels including the proximal left anterior descending (LAD) artery, CABG was performed (CABG group). If only one or two vessels were physiologically significant (not including the proximal LAD), PCI of those lesions was performed (PCI group). Of the 150 patients, 87 fulfilled the criteria for CABG and 63 for PCI. There were no significant differences in the angiographic or other baseline characteristics between the two groups. At 2-year follow-up, no differences were seen in adverse events, including repeat revascularization (event-free survival 74% in the CABG group and 72% in the PCI group). A similar number of patients were free from angina (84% in the CABG group and 82% in the PCI group). Importantly, the results in both groups were as good as the surgical groups in previous studies comparing PCI and CABG in MVD. In patients with multivessel disease, PCI in those with one or two hemodynamically significant lesions as identified by an FFR < 0.75 yields a similar favorable outcome as CABG in those with three or more culprit lesions despite a similar angiographic extent of disease.     

The Impact of Blood Pressure Variability on Coronary Arterial Lumen Dimensions as Assessed by Optical Coherence Tomography in Patients with ST-Elevation Myocardial Infarction

BackgroundPatients with ST-elevation Myocardial Infarction treated by primary percutaneous coronary intervention (PPCI) experience drastic hemodynamic systemic changes (i.e., blood pressure) during the different phases of the procedure. Optical coherence tomography is often used to unveil the underlying cause of STEMI (pre-PCI) and to optimize stent implantation (post-PCI). The impact of blood pressure variability on coronary lumen remains uncertain. This study aimed to investigate the relationship between blood pressure variability, before and after PCI, and coronary arterial lumen dimensions of the infarct-related artery.MethodsWe measured systolic, diastolic and mean arterial blood pressure (SBP, DBP, and MAP; respectively) at pre- and post-PCI. Frequency-domain optical coherence tomography (FD-OCT) imaging was performed at the same time points. Offline quantitative image analyses were performed to assess the average and minimum lumen area (LA). Δ blood pressure (after and before the PCI) was then calculated.ResultsA total of 14 ST-segment elevation myocardial infarction (STEMI) patients were included. 84.2% of enrolled patients were male with a mean age of (58 ± 10.7 years). Roughly two-thirds (57.8%) had hypertension. The mean SBP was (112.6 mm Hg ± 16.1) and (117.2 mm Hg ± 20.9), pre- and post-stenting, respectively; the range of the observed SBP differences (between pre- and post-PCI) went from −25 to +23 mm Hg. Pre- and post-stenting mean average LA were (7.1 ± 2.5 mm² and 6.8 ± 2.3 mm²; respectively). There were poor correlations between ΔSBP and Δ mean minimum LA. A similar pattern was observed with ΔDBP and ΔMAP.ConclusionDespite significant hemodynamic variability, the difference in lumen cross-sectional area, between pre- and post-coronary artery stenting was minimal. This study supports the use of OCT lumen areas to inform clinical decisions during PPCI.     

Planning percutaneous coronary interventions using computed tomography angiography and fractional flow reserve‐derived from computed tomography: A state‐of‐the‐art review

Fractional flow reserve derived by coronary computed tomography angiography (CTA; FFRCT) is an accurate noninvasive method for identifying coronary artery disease (CAD) and detecting hemodynamically significant stenosis. Although initially proposed as noninvasive tools to “rule out” significant CAD in low‐risk patients, CTA and FFRCT are now utilized in higher‐risk patients. Furthermore, new applications of CTA and FFRCT include a planning tool for percutaneous coronary intervention (PCI), which allows the cardiologist to assess lesion‐specific ischemia, plan stent locations and sizes, and use virtual remodeling of the lumen (virtual stenting) to assess the functional impact of PCI. The purpose of this review is to discuss the principles of CTA and FFRCT acquisition, and their application for PCI planning, even before invasive angiography is performed.     

A randomized controlled trial of a physiology-guided percutaneous coronary intervention optimization strategy: Rationale and design of the TARGET FFR study

Post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) ≥0.90 confers an improved cardiac prognosis. There are currently limited data available to determine how often it is possible to improve an angiographically acceptable but physiologically suboptimal result. A physiology-guided optimization strategy can achieve a clinically meaningful increase in the proportion of patients achieving a final post-PCI FFR ≥0.90 compared to standard care. Following angiographically successful PCI procedures, 260 patients will be randomized (1:1) to receive either a physiology-guided incremental optimization strategy (intervention group) or blinded post-PCI coronary physiology measurements (control group). Patients undergoing successful, standard-of-care PCI for either stable angina or non-ST-segment-elevation myocardial infarction who meet the study's inclusion and exclusion criteria will be eligible for randomization. The primary endpoint is defined as the proportion of patients with a final post-PCI FFR result ≥0.90. Secondary endpoints include change from baseline in Seattle Angina Questionnaire and EQ-5D-5L scores at 3 months and the rate of target vessel failure and its components (cardiac death, myocardial infarction, stent thrombosis, unplanned rehospitalization with target vessel revascularization) at 3 months and 1 year. 260 individual patients were successfully randomized between March 2018 and November 2019. Key baseline demographics of the study population are reported within. TARGET FFR is an investigator-initiated, prospective, single-center, randomized controlled trial of an FFR-guided PCI optimization strategy. The study has completed recruitment and is now in clinical follow-up. It is anticipated that primary results will be presented in Autumn 2020. ClinicalTrials.gov Identifier: NCT03259815. [Correction added on Apr 3 2020, after first online publication: Clinical Trials identifier added.]     

Pre-Angioplasty Instantaneous Wave-Free Ratio Pullback Predicts Hemodynamic Outcome In Humans With Coronary Artery Disease: Primary Results of the International Multicenter iFR GRADIENT Registry

Objectives

The authors sought to evaluate the accuracy of instantaneous wave-Free Ratio (iFR) pullback measurements to predict post-percutaneous coronary intervention (PCI) physiological outcomes, and to quantify how often iFR pullback alters PCI strategy in real-world clinical settings.

5-Year Outcomes According to FFR of Left Circumflex Coronary Artery After Left Main Crossover Stenting

ObjectivesThe aim of the current study was to evaluate the long-term clinical impact of fractional flow reserve (FFR) in jailed left circumflex coronary artery (LCx) after left main coronary artery (LM) simple crossover stenting.BackgroundAlthough the provisional side-branch intervention with FFR guidance has been validated for non-LM bifurcation lesions, the outcome of such a strategy in LM bifurcation disease is not well-known.MethodsPatients who underwent LM-to–left anterior descending coronary artery simple crossover stenting and who had FFR measurements in the LCx thereafter were enrolled. A low FFR was defined as ≤0.80. The clinical outcomes were assessed by the 5-year rate of target lesion failure (TLF) (a composite of cardiac death, target-vessel myocardial infarction, or target lesion revascularization).ResultsIn 83 patients, the mean FFR of the LCx after LM stenting was 0.87 ± 0.08, and 14 patients (16.9%) had a low FFR. There was no correlation between the FFR and angiographic % diameter stenosis in jailed LCx (R² = 0.039; p = 0.071) and there was no difference in the angiographic % diameter stenosis in the high and low FFR groups. At 5 years, the low FFR group had a significantly higher rate of TLF than the high FFR group (33.4% vs. 10.7%; hazard ratio: 4.09, 95% confidence interval: 1.15 to 14.52; p = 0.029). However, there was no difference in the clinical outcomes according to the angiographic % diameter stenosis. In a multivariate analysis, a low FFR was an independent predictor of the risk for a 5-year TLF (hazard ratio: 6.49; 95% confidence interval: 1.37 to 30.73; p = 0.018).ConclusionsThe patients with a high FFR in jailed LCx had better 5-year outcomes than those with a low FFR. The FFR measurement in jailed LCx can be helpful in selecting an adequate treatment strategy and may reduce unnecessary complex procedures.     

血管内超声指导经皮冠状动脉介入治疗对非ST段抬高型急性冠脉综合征临界病变患者预后的影响

目的观察血管内超声(IVUS)指导经皮冠状动脉介入(PCI)治疗对非ST段抬高型急性冠脉综合征(NSTE-ACS)临界病变患者临床预后的影响。方法入选2016年6月至2017年1月陕西省第四人民医院心血管内科冠状动脉造影(CAG)提示可行PCI术的NSTE-ACS临界病变患者100例,随机数字表法分为IVUS组和血流储备分数(FFR)组各50例,术后随访12个月,比较2组患者主要不良心血管事件(MACEs)发生情况。结果 IVUS组和FFR组患者病变血管直径[(3.5±0.7)vs(3.0±0.5)mm]、狭窄程度[(62.6±5.0)%vs(57.2±7.5)%]、病变长度[(20.2±8.8)vs(23.5±10.7)mm]、PCI相关并发症发生率[8.0%(4/50)vs 4.0%(2/50)]等差异无统计学意义(P0.05);相比FFR组患者,IVUS组患者支架植入率较高[56.0%(28/50)vs 38.0%(19/50)],但差异无统计学意义(P0.05)。术后随访12个月MACEs发生率差异无统计学意义[18.8%(9/48)vs 14.3%(7/49),P=0.55]。结论对于NSTE-ACS临界病变患者,IVUS指导血运重建治疗的短期临床预后不劣于FFR指导。     

The Impact of Virtual Fractional Flow Reserve and Virtual Coronary Intervention on Treatment Decisions in the Cardiac Catheter Laboratory

BackgroundUsing fractional flow reserve (FFR) to guide percutaneous coronary intervention for patients with coronary artery disease (CAD) improves clinical decision making but remains underused. Virtual FFR (vFFR), computed from angiographic images, permits physiologic assessment without a pressure wire and can be extended to virtual coronary intervention (VCI) to facilitate treatment planning. This study investigated the effect of adding vFFR and VCI to angiography in patient assessment and management.MethodsTwo cardiologists independently reviewed clinical data and angiograms of 50 patients undergoing invasive management of coronary syndromes, and their management plans were recorded. The vFFRs were computed and disclosed, and the cardiologists submitted revised plans. Then, using VCI, the physiologic results of various interventional strategies were shown and further revision was invited.ResultsDisclosure of vFFR led to a change in strategy in 27%. VCI led to a change in stent size in 48%. Disclosure of vFFR and VCI resulted in an increase in operator confidence in their decision. Twelve cases were reviewed by 6 additional cardiologists. There was limited agreement in the management plans between cardiologists based on either angiography (kappa = 0.31) or vFFR (kappa = 0.39).ConclusionsvFFR has the potential to alter decision making, and VCI can guide stent sizing. However, variability in management strategy remains considerable between operators, even when presented with the same anatomic and physiologic data.     

无创血流储备分数测定对冠心病患者心肌缺血功能评估的临床进展

在中度病变的稳定型冠状动脉疾病(CAD)患者中,判断病变是否造成了冠状动脉远端血流动力学的显著改变(即心肌缺血),在制定临床决策中起着至关重要的作用。而在这些临界病变中,血流储备分数(FFR)测定是识别心肌缺血存在与否的金标准。近年来,随着计算机流体动力学(CFD)的发展,基于冠状动脉CT血管造影的无创性FFR(FFRCT)得以发展。本综述旨在通过阐述FFRCT的概念及应用原理,总结目前针对FFRCT技术的几项临床研究,说明其良好的诊断性能、临床实践进展、优点、局限性以及临床应用前景。     

The effect of CTO recanalization on FFR of the donor artery

This case illustrates that fractional flow reserve (FFR) in addition to the severity and length of the coronary stenosis is critically dependent on the extent of viable myocardium perfused. In the presented case, the left anterior descending artery (LAD) that had modest angiographic stenosis supplied collaterals to the entire left ventricle. After recanalization of chronic total occlusions (CTO) of the right and circumflex arteries, FFR in the LAD had normalized. © 2011 Wiley‐Liss, Inc.     

Coronary pressure measurement based decision making for percutaneous coronary intervention

The fractional flow reserve (FFR) is a simple, reliable, and reproducible physiologic index of lesion severity. In patients with intermediate stenosis, FFR≥0.75 can be used to safely defer percutaneous coronary intervention (PCI), and patients with FFR≥0.75 have a very low cardiac event rate. Coronary pressure measurement can determine which lesion should be treated with PCI in patients with tandem lesions, and PCI on the basis of FFR has been demonstrated to result in an acceptably low repeat PCI rate. FFR can identify patients with equivocal left main coronary artery disease who benefit from coronary bypass surgery. Coronary pressure measurement distinguishes patients with an abrupt pressure drop pattern from those with a gradual pressure drop pattern, and the former group of patients benefit from PCI. Coronary pressure measurement is clinically useful in evaluating sufficient recruitable coronary collateral blood flow for prevention of ischemia, which affects future cardiac events. FFR is useful for the prediction of restenosis after PCI. As an end-point of PCI, FFR ≥0.95 and ≥0.90 would be appropriate for coronary stenting and coronary angioplasty, respectively. In summary, if you encounter a coronary stenosis in doubt you should measure pressure rather than dilate it.     

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

ObjectivesThis 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.BackgroundBoth 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.MethodsAn 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.ResultsIn 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.ConclusionsThe 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)     

Blinded Physiological Assessment of Residual Ischemia After Successful Angiographic Percutaneous Coronary Intervention: The DEFINE PCI Study

ObjectivesThis study sought to evaluate the incidence and causes of an abnormal instantaneous wave-free ratio (iFR) after angiographically successful percutaneous coronary intervention (PCI).BackgroundImpaired coronary physiology as assessed by fractional flow reserve is present in some patients after PCI and is prognostically relevant.MethodsDEFINE PCI (Physiologic Assessment of Coronary Stenosis Following PCI) was a multicenter, prospective, observational study in which a blinded iFR pull back was performed after angiographically successful PCI in 562 vessels in 500 patients. Inclusion criteria were angina with either multivessel or multilesion coronary artery disease with an abnormal baseline iFR. The primary endpoint of the study was the rate of residual ischemia after operator-assessed angiographically successful PCI, defined as an iFR <0.90. The causes of impaired iFR were categorized as stent related, untreated proximal or distal focal stenosis, or diffuse atherosclerosis.ResultsAn average of 1.1 vessels per patient had abnormal baseline iFRs, with a mean value of 0.69 ± 0.22, which improved to 0.93 ± 0.07 post-PCI. Residual ischemia after angiographically successful PCI was present in 112 patients (24.0%), with a mean iFR in that population of 0.84 ± 0.06 (range 0.60 to 0.89). Among patients with impaired post-PCI iFRs, 81.6% had untreated focal stenoses that were angiographically inapparent, and 18.4% had diffuse disease. Among the focal lesions, 38.4% were located within the stent segment, while 31.5% were proximal and 30.1% were distal to the stent. Post-PCI vessel angiographic diameter stenosis was not a predictor of impaired post-procedural iFR.ConclusionsBlinded post-PCI physiological assessment detected residual ischemia in nearly 1 in 4 patients after coronary stenting despite an operator-determined angiographically successful result. Most cases of residual ischemia were due to inapparent focal lesions potentially amenable to treatment with additional PCI. (Physiologic Assessment of Coronary Stenosis Following PCI [DEFINE PCI]; NCT03084367)