Complete vs Culprit-Only Revascularization in Older Patients With Myocardial Infarction and High Bleeding Risk: A Randomized Clinical Trial.

Importance: Patients with high bleeding risk (HBR) have a poor prognosis, and it is not known if they may benefit from complete revascularization after myocardial infarction (MI). Objective: To investigate the benefit of physiology-guided complete revascularization vs a culprit-only strategy in patients with HBR, MI, and multivessel disease. Design, Setting, and Participants: This was a prespecified analysis of the Functional Assessment in Elderly MI Patients With Multivessel Disease (FIRE) randomized clinical trial data. FIRE was an investigator-initiated, open-label, multicenter trial. Patients 75 years or older with MI and multivessel disease were enrolled at 34 European centers from July 2019 through October 2021. Physiology treatment was performed either by angiography- or wire-based assessment. Patients were divided into HBR or non-HBR categories in accordance with the Academic Research Consortium HBR document. Interventions: Patients were randomized to either physiology-guided complete revascularization or culprit-only strategy. Main Outcomes and Measures: The primary outcome comprised a composite of death, MI, stroke, or revascularization at 1 year. Secondary outcomes included a composite of cardiovascular death or MI and Bleeding Academic Research Consortium (BARC) types 3 to 5. Results: Among 1445 patients (mean [SD] age, 81 [5] years; 917 male [63%]), 1025 (71%) met HBR criteria. Patients with HBR were at higher risk for the primary end point (hazard ratio [HR], 2.01; 95% CI, 1.47-2.76), cardiovascular death or MI (HR, 1.89; 95% CI, 1.26-2.83), and BARC types 3 to 5 (HR, 3.28; 95% CI, 1.40-7.64). The primary end point was significantly reduced with physiology-guided complete revascularization as compared with culprit-only strategy in patients with HBR (HR, 0.73; 95% CI, 0.55-0.96). No indication of interaction was noted between revascularization strategy and HBR status for primary and secondary end points. Conclusions and Relevance: HBR status is prevalent among older patients with MI, significantly increasing the likelihood of adverse events. Physiology-guided complete revascularization emerges as an effective strategy, in comparison with culprit-only revascularization, for mitigating ischemic adverse events, including cardiovascular death and MI. Trial Registration: ClinicalTrials.gov Identifier: NCT03772743.

Combined use of intra-aortic balloon pump and impella in cardiogenic shock: A systematic review.

BACKGROUND: Use of Intra-Aortic Balloon Pump (IABP) in combination with Impella has been described as an alternative strategy for mechanical circulatory support (MCS) in patients with cardiogenic shock (CS). We provide a systematic review aimed to explore the effectiveness of this paired MCS approach. METHODS: We conducted a comprehensive systematic search in MEDLINE, Scopus, and Cochrane databases to identify all studies that investigated dual MCS with IABP and Impella. RESULTS: Our search strategy identified 12 articles, including 1 randomized controlled trial, 1 retrospective study, 1 case series, 7 case report and 2 animal studies. Rationale for this combined MCS strategy stems from an observed reduction in myocardial oxygen demand/supply ratio compared to the use of each device alone, without determining significant variations in left ventricular work. Nonetheless, this combined approach also leads to a 30-40 % decline in Impella flow, increasing the risk of bleeding, Impella displacement, as well as triggering positioning and pressure alarms. Additionally, hemolytic risk data yielded inconclusive results. Importantly, there were no notable disparities in mortality rates when comparing the combined strategy to the use of each device individually. CONCLUSION: At the current state-of-the-art, there are no conclusive data demonstrating net clinical benefits of combining Impella with IABP. Considering the substantial risks of morbidity associated, we recommend against its use in clinical practice.

Coronary Sinus Narrowing Improves Coronary Microcirculation Function in Patients With Refractory Angina: A Multicenter Prospective INROAD Study.

BACKGROUND: The underlying mechanisms responsible for the clinical benefits following coronary sinus narrowing and pressure elevation remain unclear. The present study aims to investigate whether coronary sinus narrowing improves the indexes of coronary microcirculatory function. METHODS: Patients with refractory angina who had a clinical indication for reducer implantation underwent invasive physiological assessments before and 4 months after the procedure. The primary outcome was the change in the values of the index of microcirculatory resistance. Secondary end points included changes in coronary flow reserve and the resistive resistance ratio values. Angina status was assessed with the Canadian Cardiology Society class and the Seattle Angina Questionnaire. RESULTS: Twenty-four patients with a history of obstructive coronary artery disease and prior coronary revascularization (surgical and percutaneous) treated with reducer implantation were enrolled, and 21 of them (87%) underwent repeated invasive coronary physiological assessment after 4 months. The index of microcirculatory resistance values decreased from 33.35±19.88 at baseline to 15.42±11.36 at 4-month follow-up (P<0.001; mean difference, -17.90 [95% CI, -26.16 to -9.64]). A significant (≥20% from baseline) reduction of the index of microcirculatory resistance was observed in 15 (71.4% [95% CI, 47.8%-88.7%]) patients. The number of patients with abnormal index of microcirculatory resistance (≥25) decreased from 12 (57%) to 4 (19%; P=0.016). Coronary flow reserve increased from 2.46±1.52 to 4.20±2.52 (mean difference, 1.73 [95% CI, 0.51-2.96]). Similar findings were observed for resistive resistance ratio values. Overall, 16 patients (76.1%) had an improvement of 1 Canadian Cardiology Society class. Seattle Angina Questionnaire summary score increase of around 3 points (3.01 [95% CI, 1.39-4.61]). CONCLUSIONS: Coronary sinus reduction implantation is associated with a significant improvement in the parameters of coronary microcirculatory function. These findings provide insights into the improvement of angina symptoms and may have implications for the treatment of coronary microvascular dysfunction. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05174572.

Coronary Physiology Guidance vs Conventional Angiography for Optimization of Percutaneous Coronary Intervention: The AQVA-II Trial.

BACKGROUND: The debate surrounding the efficacy of coronary physiological guidance compared with conventional angiography in achieving optimal post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) values persists. OBJECTIVES: The primary aim of this study was to demonstrate the superiority of physiology-guided PCI, using either angiography or microcatheter-derived FFR, over conventional angiography-based PCI in complex high-risk indicated procedures (CHIPs). The secondary aim was to establish the noninferiority of angiography-derived FFR guidance compared with microcatheter-derived FFR guidance. METHODS: Patients with obstructive coronary lesions and meeting CHIP criteria were randomized 2:1 to receive undergo physiology- or angiography-based PCI. Those assigned to the former were randomly allocated to angiography- or microcatheter-derived FFR guidance. CHIP criteria were long lesion (>28 mm), tandem lesions, severe calcifications, severe tortuosity, true bifurcation, in-stent restenosis, and left main stem disease. The primary outcome was invasive post-PCI FFR value. The optimal post-PCI FFR value was defined as >0.86. RESULTS: A total of 305 patients (331 study vessels) were enrolled in the study (101 undergoing conventional angiography-based PCI and 204 physiology-based PCI). Optimal post-PCI FFR values were more frequent in the physiology-based PCI group compared with the conventional angiography-based PCI group (77% vs 54%; absolute difference 23%, relative difference 30%; P < 0.0001). The occurrence of the primary outcome did not differ between the 2 physiology-based PCI subgroups, demonstrating the noninferiority of angiography- vs microcatheter-derived FFR (P < 0.01). CONCLUSIONS: In CHIP patients, procedural planning and guidance on the basis of physiology (through either angiography- or microcatheter-derived FFR) are superior to conventional angiography for achieving optimal post-PCI FFR values. (Physiology Optimized Versus Angio-Guided PCI [AQVA-II]; NCT05658952).

Functional (Re)Development of SYNTAX Score II 2020: Predictive Performance and Risk Assessment.

The present study investigates the prognostic value of the Syntax Score II 2020 corrected for flow-limiting lesions and its ability to better address treatment by benefit prediction among patients with left main or multivessel disease. We analyzed 1274 patients from the HALE-BOPP cohort and integrated the Syntax Score II 2020 with the result of the fractional flow reserve (FFR) evaluation. Absolute risk difference (ARD) between surgical and percutaneous revascularization was calculated for anatomic and functional Syntax Score II 2020 predicted mortality. The ARD allowed to stratify the population into two large categories: "coronary artery bypass graft (CABG) better" with ARD ≥ 4.5% and "CABG-percutaneous coronary intervention (PCI) equipoise" with ARD < 4.5%. The mean global anatomical Syntax Score was 15.5 ± 9.2, whereas the functional one was 9.5 ± 10 (p < 0.01). Using the anatomic Syntax Score II 2020, 881 patients had a CABG-PCI equipoise. This number increased to 1041 after considering only flow-limiting lesions by FFR (p < 0.001); therefore, 40% of CABG better patients were reclassified within the CABG-PCI equipoise category. Kaplan-Maier curves showed similar actual survival rates for patients originally with CABG-PCI equipoise and those reclassified, in both cases higher than those from CABG better patients (p < 0.01). The integration between Syntax Score II 2020 and physiology is feasible, and merging clinical, anatomic and functional data allows for better risk prediction and therapeutic guidance.

Complete or Culprit-Only PCI in Older Patients with Myocardial Infarction.

BACKGROUND: The benefit of complete revascularization in older patients (≥75 years of age) with myocardial infarction and multivessel disease remains unclear. METHODS: In this multicenter, randomized trial, we assigned older patients with myocardial infarction and multivessel disease who were undergoing percutaneous coronary intervention (PCI) of the culprit lesion to receive either physiology-guided complete revascularization of nonculprit lesions or to receive no further revascularization. Functionally significant nonculprit lesions were identified either by pressure wire or angiography. The primary outcome was a composite of death, myocardial infarction, stroke, or any revascularization at 1 year. The key secondary outcome was a composite of cardiovascular death or myocardial infarction. Safety was assessed as a composite of contrast-associated acute kidney injury, stroke, or bleeding. RESULTS: A total of 1445 patients underwent randomization (720 to receive complete revascularization and 725 to receive culprit-only revascularization). The median age of the patients was 80 years (interquartile range, 77 to 84); 528 patients (36.5%) were women, and 509 (35.2%) were admitted for ST-segment elevation myocardial infarction. A primary-outcome event occurred in 113 patients (15.7%) in the complete-revascularization group and in 152 patients (21.0%) in the culprit-only group (hazard ratio, 0.73; 95% confidence interval [CI], 0.57 to 0.93; P = 0.01). Cardiovascular death or myocardial infarction occurred in 64 patients (8.9%) in the complete-revascularization group and in 98 patients (13.5%) in the culprit-only group (hazard ratio, 0.64; 95% CI, 0.47 to 0.88). The safety outcome did not appear to differ between the groups (22.5% vs. 20.4%; P = 0.37). CONCLUSIONS: Among patients who were 75 years of age or older with myocardial infarction and multivessel disease, those who underwent physiology-guided complete revascularization had a lower risk of a composite of death, myocardial infarction, stroke, or ischemia-driven revascularization at 1 year than those who received culprit-lesion-only PCI. (Funded by Consorzio Futuro in Ricerca and others; FIRE ClinicalTrials.gov number, NCT03772743.).

Interventional Versus Conservative Strategy in Patients With Spontaneous Coronary Artery Dissections: Insights From DISCO Registry.

BACKGROUND: The optimal management of patients with spontaneous coronary artery dissection remains debated. METHODS: Patients enrolled in the DISCO (Dissezioni Spontanee Coronariche) Registry up to December 2020 were included. The primary end point was major adverse cardiovascular events, a composite of all-cause death, nonfatal myocardial infarction, and repeat percutaneous coronary intervention (PCI). Independent predictors of PCI and medical management were investigated. RESULTS: Among 369 patients, 129 (35%) underwent PCI, whereas 240 (65%) were medically managed. ST-segment-elevation myocardial infarction (68% versus 35%, P<0.001), resuscitated cardiac arrest (9% versus 3%, P<0.001), proximal coronary segment involvement (32% versus 7%, P<0.001), and Thrombolysis in Myocardial Infarction flow 0 to 1 (54% versus 20%, P<0.001) were more frequent in the PCI arm. In-hospital event rates were similar. Between patients treated with PCI and medical therapy, there were no differences in terms of major adverse cardiovascular events at 2 years (13.9% versus 11.7%, P=0.467), all-cause death (0.7% versus 0.4%, P=0.652), myocardial infarction (9.3% versus 8.3%, P=0.921) and repeat PCI (12.4% versus 8.7%, P=0.229). ST-segment-elevation myocardial infarction at presentation (odds ratio [OR], 3.30 [95% CI, 1.56-7.12]; P=0.002), proximal coronary segment involvement (OR, 5.43 [95% CI, 1.98-16.45]; P=0.002), Thrombolysis in Myocardial Infarction flow grade 0 to 1 and 2 (respectively, OR, 3.22 [95% CI, 1.08-9.96]; P=0.038; and OR, 3.98 [95% CI, 1.38-11.80]; P=0.009) and luminal narrowing (OR per 5% increase, 1.13 [95% CI, 1.01-1.28]; P=0.037) were predictors of PCI, whereas the 2B-angiographic subtype predicted medical management (OR, 0.25 [95% CI, 0.07-0.83]; P=0.026). CONCLUSIONS: Clinical presentation and procedural variables drive the choice of the initial therapeutic approach in spontaneous coronary artery dissection. If PCI is needed, it seems to be associated with a similar risk of short-to-mid-term adverse events compared to medical treatment. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04415762.

Long-Term Outcome of Drug-Coated Balloon vs Drug-Eluting Stent for Small Coronary Vessels: PICCOLETO-II 3-Year Follow-Up.

BACKGROUND: Native vessel coronary artery disease represents 1 of the most attractive fields of application for drug-coated balloons (DCBs). To date, several devices have been compared with drug-eluting stents (DESs) in this setting with different outcomes. OBJECTIVES: The authors sought to compare the short- and long-term performance of the paclitaxel DCB with the everolimus-eluting stent in patients with de novo lesions in small coronary vessel disease. METHODS: PICCOLETO II (Drug Eluting Balloon Efficacy for Small Coronary Vessel Disease Treatment) was an academic, international, investigator-driven, multicenter, open-label randomized clinical trial in which patients were allocated to a DCB (n = 118) or DES (n = 114). We previously reported the superiority of DCBs regarding in-lesion late lumen loss at 6 months. Herein we report the final 3-year clinical follow-up with the occurrence of major adverse cardiac events (MACEs), a composite of cardiac death, nonfatal myocardial infarction, target lesion revascularization, and its individual components. RESULTS: The 3-year clinical follow-up (median 1,101 days; IQR: 1,055-1,146 days) was available for 102 patients allocated to DCB and 101 to DES treatment. The cumulative rate of all-cause death (4% vs 3.9%; P = 0.98), cardiac death (1% vs 1.9%; P = 0.56), myocardial infarction (6.9% vs 2%; P = 0.14), and target lesion revascularization (14.8% vs 8.8%; P = 0.18) did not significantly differ between DCBs and DESs. MACEs and acute vessel occlusion occurred more frequently in the DES group (20.8% vs 10.8% [P = 0.046] and 4% vs 0% [P = 0.042], respectively). CONCLUSIONS: The long-term clinical follow-up of the PICCOLETO II randomized clinical trial shows a higher risk of MACEs in patients with de novo lesions in small vessel disease when they are treated with the current-generation DES compared with the new-generation paclitaxel DCB. (Drug Eluting Balloon Efficacy for Small Coronary Vessel Disease Treatment [PICCOLETO II]; NCT03899818).

Long-term outcomes of patients treated with sirolimus-eluting resorbable magnesium scaffolds: Insights from the SHERPA-MAGIC study.

BACKGROUND: The resorbable magnesium scaffold (RMS) is a second-generation bioresorbable scaffold (BRS) that has shown conflicting results in previous studies. These findings suggest that patient selection and implantation technique may have an impact on clinical outcomes. This study aimed to investigate the safety and long-term effectiveness of RMS in a narrowly selected population. METHODS: SHERPA-MAGIC is an investigator-driven, multicenter, prospective, single-arm study that enrolled patients undergoing BRS coronary implantation in 18 Italian centers. The present analysis considered the first 543 enrolled patients treated with RMS, with a minimum follow-up of 1 year. The study protocol included strict criteria for patient selection and standardization of RMS implantation. The primary outcome was the occurrence of the vessel-oriented composite endpoints (VOCE), including cardiac death, target vessel myocardial infarction, and ischemia-driven target vessel revascularization. RESULTS: Overall, 635 vessels were treated. The 1-year cumulative occurrence of VOCE was 22 (3.5%, 95% CI 2.2%-5.2%), which was significantly lower than the prespecified estimation (from 5.5% to 8.5%). At the median follow-up of 3.5 [2.6-4.3] years, there were 3 (0.5%) cardiac deaths, 12 (1.9%) target vessel myocardial infarctions, and 33 (5.2%) ischemia-driven target vessel revascularizations. A total of 37 (5.8%, 95%CI 4.1%-7.9%) VOCEs were detected. Scaffold thrombosis occurred in 4 (0.6%, 95%CI 0.1%-1.6%) cases. Patient-level analysis confirmed the findings of the vessel-level analysis. CONCLUSIONS: These results confirm the safety and performance of RMS technology. If confirmed in randomized controlled trials, they may rekindle interest in the use of scaffolds in daily practice.

QFR-Based Virtual PCI or Conventional Angiography to Guide PCI: The AQVA Trial.

BACKGROUND: Post-percutaneous coronary intervention (PCI) quantitative flow ratio (QFR) values ≥0.90 are associated with a low incidence of adverse events. OBJECTIVES: The AQVA (Angio-based Quantitative Flow Ratio Virtual PCI Versus Conventional Angio-guided PCI in the Achievement of an Optimal Post-PCI QFR) trial aims to test whether a QFR-based virtual percutaneous coronary intervention (PCI) is superior to a conventional angiography-based PCI at obtaining optimal post-PCI QFR results. METHODS: The AQVA trial is an investigator-initiated, randomized, controlled, parallel-group clinical trial. A total of 300 patients (356 study vessels) undergoing PCI were randomized 1:1 to receive either QFR-based virtual PCI or angiography-based PCI (standard of care). The primary outcome was the rate of study vessels with a suboptimal post-PCI QFR value, which was defined as <0.90. Secondary outcomes were procedure duration, stent length/lesion, and stent number/patient. RESULTS: Overall, 38 (10.7%) study vessels missed the prespecified optimal post-PCI QFR target. The primary outcome occurred significantly more frequently in the angiography-based group (n = 26, 15.1%) compared with the QFR-based virtual PCI group (n = 12 [6.6%]; absolute difference = 8.5%; relative difference = 57%; P = 0.009). The main cause of a suboptimal result in the angiography-based group is the underestimation of a diseased segment outside the stented one. There were no significant differences among secondary endpoints, although stent length/lesion and stent number/patient were numerically lower in the virtual PCI group (P = 0.06 and P = 0.08, respectively), whereas procedure length was higher in the virtual PCI group (P = 0.06). CONCLUSIONS: The AQVA trial demonstrated the superiority of QFR-based virtual PCI over angiography-based PCI with regard to post-PCI optimal physiological results. Future larger randomized clinical trials that demonstrate the superiority of this approach in terms of clinical outcomes are warranted. (Angio-based Quantitative Flow Ratio Virtual PCI Versus Conventional Angio-guided PCI in the Achievement of an Optimal Post-PCI QFR [AQVA]; NCT04664140).

Neural interfaces to monitor Interventional Cardiologists' mental workload: GAME-ON SAGA.

BACKGROUND: Interventional cardiologists' mental workload may impact on their performance as well as on patients' outcome. Nevertheless, little attention is paid to the monitoring and optimization of their mental status. Electroencephalogram (EEG)-based neural-interfaces can estimate mental fatigue and sleepiness through spectral analysis techniques and the amplitude of alpha waves is a widely validated indicator of mental engagement's level. METHODS: The present study aims to describe mental fatigue and sleepiness through variation of psychometrics and neurometrics during a work shift in a population of 7 interventional cardiologists. Neurometrics have been acquired at the beginning of the shift, before and after each procedure performed during 127 valid Alpha Attenuation Protocols (AAP), a practical test to quantify sleepiness measuring alpha power during 2 cycle of eye opening/closing protocol. We collected alpha waves' power measures obtained during resting condition (AA Coefficient-eyes open [AAC-eo], AAC-eyes closed [AAC-ec] and AAC-mean), related to fatigue, and AAC-ec/AAC-eo (AAC-ratio), related to sleepiness. RESULTS: From a two-months observation, the first interesting preliminary results emerged: 1) AAC-mean showed an upward trend during the working day, reflecting an increase in mental fatigue (P=0.01); 2) population-level psychometrics trend confirms the same tendency described by neurometrics, possibly reflecting a reduced awareness of the operator of his/her actual mental status. CONCLUSIONS: Developing a low cost and high feasibility device to monitor and analyze operator's mental engagement level could be extremely appealing, considering the lack of data in literature for interventional disciplines and recent technology developments.

Impact of trans-stent gradient on outcome after PCI: results from a HAWKEYE substudy.

To test whether quantitative flow ratio (QFR)-based trans-stent gradient (TSG) is associated with adverse clinical events at follow-up. A post-hoc analysis of the multi-center HAWKEYE study was performed. Vessels post-PCI were divided into four groups (G) as follows: G1: QFR ≥ 0.90 TSG = 0 (n = 412, 54.8%); G2: QFR ≥ 0.90, TSG > 0 (n = 216, 28.7%); G3: QFR < 0.90, TSG = 0 (n = 37, 4.9%); G4: QFR < 0.90, TSG > 0 (n = 86, 11.4%). Cox proportional hazards regression model was used to analyze the effect of baseline and prognostic variables. The final reduced model was obtained by backward stepwise variable selection. Receiver operating characteristic (ROC) was plotted and area under the curve (AUC) was calculated and reported. Overall, 449 (59.8%) vessels had a TSG = 0 whereas (40.2%) had TSG > 0. Ten (2.2%) vessel-oriented composite endpoint (VOCE) occurred in vessels with TSG = 0, compared with 43 (14%) in vessels with TSG > 0 (p < 0.01). ROC analysis showed an AUC of 0.74 (95% CI: 0.67 to 0.80; p < 0.001). TSG > 0 was an independent predictor of the VOCE (HR 2.95 [95% CI 1.77-4.91]). The combination of higher TSG and lower final QFR (G4) showed the worst long-term outcome while low TSG and high QFR showed the best outcome (G1) while either high TSG or low QFR (G2, G3) showed intermediate and comparable outcomes. Higher trans-stent gradient was an independent predictor of adverse events and identified a subgroup of patients at higher risk for poor outcomes even when vessel QFR was optimal (> 0.90).

Complete versus culprit-only strategy in older MI patients with multivessel disease.

AIMS: The revascularization strategy to pursue in older myocardial infarction (MI) patients with multivessel disease (MVD) is currently unknown. For this reason, while waiting for the results of dedicated trials, we sought to compare a complete versus a culprit-only strategy in older MI patients by merging data from four registries. METHODS AND RESULTS: The inclusion criteria for the target population of the present study were (i) age ≥ 75 years; (ii) MI (STE or NSTE); (iii) MVD; (iv) successful treatment of culprit lesion. Propensity scores (PS) were derived using logistic regression (backward stepwise selection, p < 0.2). The primary outcome was all-cause mortality. Secondary outcomes were cardiovascular (CV) death, MI, and major bleeding. Multivariable adjustment included the PS and inverse probability of treatment weighting (IPTW). The Kaplan-Meier plots were weighted for IPT. Among 2087 patients included, 1362 (65%) received culprit-only treatment whereas 725 (35%) complete revascularization. The mean age was 81.5 years, while the mean follow-up was 419 ± 284 days. Seventy-four patients (10%) died in the complete group and 223 in the culprit-only one (16%). The adjusted cumulative 1-year mortality was 9.7% in the complete and 12.9% in the culprit-only group (adjusted HR: 0.67, 95% CI: 0.50-0.89). Complete revascularization was associated with lower incidence of CV death (adjusted HR: 0.68, 95% CI: 0.48-0.95) and MI (adjusted HR 0.67, 95% CI: 0.48-0.95). CONCLUSIONS: Culprit-only is the default strategy in older MI patients with MVD. In our analysis, complete revascularization was associated with lower all-cause and CV mortality and with a lower MI rate.

Reproducibility of quantitative flow ratio: the QREP study.

BACKGROUND: Quantitative flow ratio (QFR) is a tool for physiological lesion assessment based on invasive coronary angiography. AIMS: We aimed to assess the reproducibility of QFR computed from the same angiograms as assessed by multiple observers from different, international sites. METHODS: We included 50 patients previously enrolled in dedicated QFR studies. QFR was computed twice, one month apart by five blinded observers. The main analysis was the coefficient of variation (CV) as a measure of intra- and inter-observer reproducibility. Key secondary analysis was the identification of clinical and procedural characteristics predicting reproducibility. RESULTS: The intra-observer CV ranged from 2.3% (1.5-2.8) to 10.2% (6.6-12.0) among the observers. The inter-observer CV was 9.4% (8.0-10.5). The QFR observer, low angiographic quality, and low fractional flow reserve (FFR) were independent predictors of a large absolute difference between repeated QFR measurements defined as a difference larger than the median difference (>0.03). CONCLUSIONS: The inter- and intra-observer reproducibility for QFR computed from the same angiograms ranged from high to poor among multiple observers from different sites with an average agreement of 0.01±0.08 for repeated measurements. The reproducibility was dependent on the observer, angiographic quality and the coronary artery stenosis severity as assessed by FFR.