Influence of Pathophysiologic Patterns of Coronary Artery Disease on Immediate Percutaneous Coronary Intervention Outcomes.

BACKGROUND: Diffuse coronary artery disease affects the safety and efficacy of percutaneous coronary intervention (PCI). Pathophysiologic coronary artery disease patterns can be quantified using fractional flow reserve (FFR) pullbacks incorporating the pullback pressure gradient (PPG) calculation. This study aimed to establish the capacity of PPG to predict optimal revascularization and procedural outcomes. METHODS: This prospective, investigator-initiated, single-arm, multicenter study enrolled patients with at least one epicardial lesion with an FFR ≤0.80 scheduled for PCI. Manual FFR pullbacks were used to calculate PPG. The primary outcome of optimal revascularization was defined as an FFR ≥0.88 after PCI. RESULTS: A total of 993 patients with 1044 vessels were included. The mean FFR was 0.68±0.12, PPG 0.62±0.17, and the post-PCI FFR was 0.87±0.07. PPG was significantly correlated with the change in FFR after PCI (r=0.65 [95% CI, 0.61-0.69]; P<0.001) and demonstrated excellent predictive capacity for optimal revascularization (area under the receiver operating characteristic curve, 0.82 [95% CI, 0.79-0.84]; P<0.001). FFR alone did not predict revascularization outcomes (area under the receiver operating characteristic curve, 0.54 [95% CI, 0.50-0.57]). PPG influenced treatment decisions in 14% of patients, redirecting them from PCI to alternative treatment modalities. Periprocedural myocardial infarction occurred more frequently in patients with low PPG (<0.62) compared with those with focal disease (odds ratio, 1.71 [95% CI, 1.00-2.97]). CONCLUSIONS: Pathophysiologic coronary artery disease patterns distinctly affect the safety and effectiveness of PCI. PPG showed an excellent predictive capacity for optimal revascularization and demonstrated added value compared with an FFR measurement. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04789317.

Fractional Flow Reserve-Guided PCI as Compared with Coronary Bypass Surgery.

BACKGROUND: Patients with three-vessel coronary artery disease have been found to have better outcomes with coronary-artery bypass grafting (CABG) than with percutaneous coronary intervention (PCI), but studies in which PCI is guided by measurement of fractional flow reserve (FFR) have been lacking. METHODS: In this multicenter, international, noninferiority trial, patients with three-vessel coronary artery disease were randomly assigned to undergo CABG or FFR-guided PCI with current-generation zotarolimus-eluting stents. The primary end point was the occurrence within 1 year of a major adverse cardiac or cerebrovascular event, defined as death from any cause, myocardial infarction, stroke, or repeat revascularization. Noninferiority of FFR-guided PCI to CABG was prespecified as an upper boundary of less than 1.65 for the 95% confidence interval of the hazard ratio. Secondary end points included a composite of death, myocardial infarction, or stroke; safety was also assessed. RESULTS: A total of 1500 patients underwent randomization at 48 centers. Patients assigned to undergo PCI received a mean (±SD) of 3.7±1.9 stents, and those assigned to undergo CABG received 3.4±1.0 distal anastomoses. The 1-year incidence of the composite primary end point was 10.6% among patients randomly assigned to undergo FFR-guided PCI and 6.9% among those assigned to undergo CABG (hazard ratio, 1.5; 95% confidence interval [CI], 1.1 to 2.2), findings that were not consistent with noninferiority of FFR-guided PCI (P = 0.35 for noninferiority). The incidence of death, myocardial infarction, or stroke was 7.3% in the FFR-guided PCI group and 5.2% in the CABG group (hazard ratio, 1.4; 95% CI, 0.9 to 2.1). The incidences of major bleeding, arrhythmia, and acute kidney injury were higher in the CABG group than in the FFR-guided PCI group. CONCLUSIONS: In patients with three-vessel coronary artery disease, FFR-guided PCI was not found to be noninferior to CABG with respect to the incidence of a composite of death, myocardial infarction, stroke, or repeat revascularization at 1 year. (Funded by Medtronic and Abbott Vascular; FAME 3 ClinicalTrials.gov number, NCT02100722.).

Fractional Flow Reserve-Guided PCI or Coronary Bypass Surgery for 3-Vessel Coronary Artery Disease: 3-Year Follow-Up of the FAME 3 Trial.

BACKGROUND: Previous studies comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) in patients with multivessel coronary disease not involving the left main have shown significantly lower rates of death, myocardial infarction (MI), or stroke after CABG. These studies did not routinely use current-generation drug-eluting stents or fractional flow reserve (FFR) to guide PCI. METHODS: FAME 3 (Fractional Flow Reserve versus Angiography for Multivessel Evaluation) is an investigator-initiated, multicenter, international, randomized trial involving patients with 3-vessel coronary artery disease (not involving the left main coronary artery) in 48 centers worldwide. Patients were randomly assigned to receive FFR-guided PCI using zotarolimus drug-eluting stents or CABG. The prespecified key secondary end point of the trial reported here is the 3-year incidence of the composite of death, MI, or stroke. RESULTS: A total of 1500 patients were randomized to FFR-guided PCI or CABG. Follow-up was achieved in >96% of patients in both groups. There was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI compared with CABG (12.0% versus 9.2%; hazard ratio [HR], 1.3 [95% CI, 0.98-1.83]; P=0.07). The rates of death (4.1% versus 3.9%; HR, 1.0 [95% CI, 0.6-1.7]; P=0.88) and stroke (1.6% versus 2.0%; HR, 0.8 [95% CI, 0.4-1.7]; P=0.56) were not different. MI occurred more frequently after PCI (7.0% versus 4.2%; HR, 1.7 [95% CI, 1.1-2.7]; P=0.02). CONCLUSIONS: At 3-year follow-up, there was no difference in the incidence of the composite of death, MI, or stroke after FFR-guided PCI with current-generation drug-eluting stents compared with CABG. There was a higher incidence of MI after PCI compared with CABG, with no difference in death or stroke. These results provide contemporary data to allow improved shared decision-making between physicians and patients with 3-vessel coronary artery disease. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02100722.

Continuous thermodilution and microvascular resistance reserve during the index procedure in acute coronary syndrome without obstructive coronary artery disease: A pilot study.

BACKGROUND: In 5%-25% of non-ST-elevation acute coronary syndrome (NSTE-ACS) patients, coronary angiography reveals no obstructive coronary arteries (MINOCA). Coronary microvascular disease (CMD) is a potential causal pathophysiological mechanism in these patients and can be diagnosed by continuous thermodilution assessment. Recently, the microvascular resistance reserve (MRR) has been introduced as a novel index to assess the vasodilatory capacity of the microcirculation. However, continuous thermodilution and MRR have never been investigated in the acute setting in MINOCA patients and invasive assessment of the microcirculation in these patients are currently lacking. AIMS: The objectives of the study were to investigate the incidence of CMD (MRR ≤ 2.7) in patients with MINOCA and to evaluate the feasibility and safety of continuous thermodilution-based assessment during index coronary angiography in the acute setting. METHODS: This study was a prospective, observational, pilot study investigating coronary physiology in the acute setting in MINOCA patients. Patients admitted with a diagnosis of NSTE-ACS were eligible for inclusion. RESULTS: In total, 19 MINOCA patients were included in this analysis; the mean age was 70 ± 9 years, and 79% were females. CMD was present in 6 patients (32%). Qrest was significantly higher in the MRR ≤ 2.7 group compared to the MRR > 2.7 group (0.076 [0.057-0.100] vs. 0.049 [0.044-0.071] L/min, p = 0.03). Rµ,rest was significantly lower in the MRR ≤ 2.7 group compared to the MRR > 2.7 group (1083 [710-1510] vs. 1563 [1298-1970] WU, p = 0.04). No periprocedural complications or hemodynamic instability have occurred during continuous thermodilution assessment during the index coronary angiography. CONCLUSION: In patients admitted for MINOCA undergoing immediate coronary angiography, continuous thermodilution assessment and MRR are feasible and safe in the acute setting, and evidence of functional CMD could be observed in one-third of the MINOCA patients.

Quality of Life After Fractional Flow Reserve-Guided PCI Compared With Coronary Bypass Surgery.

BACKGROUND: Previous studies have shown that quality of life improves after coronary revascularization more so after coronary artery bypass grafting (CABG) than after percutaneous coronary intervention (PCI). This study aimed to evaluate the effect of fractional flow reserve guidance and current generation, zotarolimus drug-eluting stents on quality of life after PCI compared with CABG. METHODS: The FAME 3 trial (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) is a multicenter, international trial including 1500 patients with 3-vessel coronary artery disease who were randomly assigned to either CABG or fractional flow reserve-guided PCI. Quality of life was measured using the European Quality of Life-5 Dimensions (EQ-5D) questionnaire at baseline and 1 and 12 months. The Canadian Cardiovascular Class angina grade and working status were assessed at the same time points and at 6 months. The primary objective was to compare EQ-5D summary index at 12 months. Secondary end points included angina grade and work status. RESULTS: The EQ-5D summary index at 12 months did not differ between the PCI and CABG groups (difference, 0.001 [95% CI, -0.016 to 0.017]; P=0.946). The trajectory of EQ-5D during the 12 months differed (P<0.001) between PCI and CABG: at 1 month, EQ-5D was 0.063 (95% CI, 0.047 to 0.079) higher in the PCI group. A similar trajectory was found for the EQ (EuroQol) visual analogue scale. The proportion of patients with Canadian Cardiovascular Class 2 or greater angina at 12 months was 6.2% versus 3.1% (odds ratio, 2.5 [95% CI, 0.96-6.8]), respectively, in the PCI group compared with the CABG group. A greater percentage of younger patients (<65 years old) were working at 12 months in the PCI group compared with the CABG group (68% versus 57%; odds ratio, 3.9 [95% CI, 1.7-8.8]). CONCLUSIONS: In the FAME 3 trial, quality of life after fractional flow reserve-guided PCI with current generation drug-eluting stents compared with CABG was similar at 1 year. The rate of significant angina was low in both groups and not significantly different. The trajectory of improvement in quality of life was significantly better after PCI, as was working status in those <65 years old. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02100722.

Automation of intracoronary continuous thermodilution for absolute coronary flow and microvascular resistance measurements.

AIM: Microvascular resistance reserve (MRR) as derived from continuous intracoronary thermodilution specifically quantifies microvasculature function. As originally described, the technique necessitates reinstrumentation of the artery and manual reprogramming of the infusion pump when performing resting and hyperemic measurements. To simplify and to render this procedure operator-independent, we developed a fully automated method. The aim of the present study is to validate the automated procedure against the originally described one. METHODS AND RESULTS: For the automated procedure, an infusion pump was preprogrammed to allow paired resting-hyperemic thermodilution assessment without interruption. To validate the accuracy of this new approach, 20 automated measurements were compared to those obtained in the same vessels with conventional paired resting-hyperemic thermodilution measurements (i.e., with a sensor pullback at each infusion rate and manual reprogramming of the infusion pump).  A close correlation between the conventional and the automated measuring technique was found for resting flow (Qrest : r = 0.89, mean bias = 2.52; SD = 15.47), hyperemic flow (Qhyper : r = 0.88, mean bias = -2.65; SD = 27.96), resting microvascular resistance (Rµ-rest : r = 0.90, mean bias = 52.14; SD = 228.29), hyperemic microvascular resistance Rµ-hyper : r = 0.92, mean bias = 12.95; SD = 57.80), and MRR (MRR: r = 0.89, mean bias = 0.04, SD = 0.59).  Procedural time was significantly shorter with the automated method (5'25″ ± 1'23″ vs. 4'36″ ± 0'33″, p = 0.013). CONCLUSION: Continuous intracoronary thermodilution-derived measurements of absolute flow, absolute resistance, and MRR can be fully automated. This further shortens and simplifies the procedure when performing paired resting-hyperemic measurements.

Prognostic value of comprehensive intracoronary physiology assessment early after heart transplantation.

AIMS: We evaluated the long-term prognostic value of invasively assessing coronary physiology after heart transplantation in a large multicentre registry. METHODS AND RESULTS: Comprehensive intracoronary physiology assessment measuring fractional flow reserve (FFR), the index of microcirculatory resistance (IMR), and coronary flow reserve (CFR) was performed in 254 patients at baseline (a median of 7.2 weeks) and in 240 patients at 1 year after transplantation (199 patients had both baseline and 1-year measurement). Patients were classified into those with normal physiology, reduced FFR (FFR ≤ 0.80), and microvascular dysfunction (either IMR ≥ 25 or CFR ≤ 2.0 with FFR > 0.80). The primary outcome was the composite of death or re-transplantation at 10 years. At baseline, 5.5% had reduced FFR; 36.6% had microvascular dysfunction. Baseline reduced FFR [adjusted hazard ratio (aHR) 2.33, 95% confidence interval (CI) 0.88-6.15; P = 0.088] and microvascular dysfunction (aHR 0.88, 95% CI 0.44-1.79; P = 0.73) were not predictors of death and re-transplantation at 10 years. At 1 year, 5.0% had reduced FFR; 23.8% had microvascular dysfunction. One-year reduced FFR (aHR 2.98, 95% CI 1.13-7.87; P = 0.028) and microvascular dysfunction (aHR 2.33, 95% CI 1.19-4.59; P = 0.015) were associated with significantly increased risk of death or re-transplantation at 10 years. Invasive measures of coronary physiology improved the prognostic performance of clinical variables (χ2 improvement: 7.41, P = 0.006). However, intravascular ultrasound-derived changes in maximal intimal thickness were not predictive of outcomes. CONCLUSION: Abnormal coronary physiology 1 year after heart transplantation was common and was a significant predictor of death or re-transplantation at 10 years.

Five-Year Outcomes with PCI Guided by Fractional Flow Reserve.

BACKGROUND: We hypothesized that fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) would be superior to medical therapy as initial treatment in patients with stable coronary artery disease. METHODS: Among 1220 patients with angiographically significant stenoses, those in whom at least one stenosis was hemodynamically significant (FFR, ≤0.80) were randomly assigned to FFR-guided PCI plus medical therapy or to medical therapy alone. Patients in whom all stenoses had an FFR of more than 0.80 received medical therapy and were entered into a registry. The primary end point was a composite of death, myocardial infarction, or urgent revascularization. RESULTS: A total of 888 patients underwent randomization (447 patients in the PCI group and 441 in the medical-therapy group). At 5 years, the rate of the primary end point was lower in the PCI group than in the medical-therapy group (13.9% vs. 27.0%; hazard ratio, 0.46; 95% confidence interval [CI], 0.34 to 0.63; P<0.001). The difference was driven by urgent revascularizations, which occurred in 6.3% of the patients in the PCI group as compared with 21.1% of those in the medical-therapy group (hazard ratio, 0.27; 95% CI, 0.18 to 0.41). There were no significant differences between the PCI group and the medical-therapy group in the rates of death (5.1% and 5.2%, respectively; hazard ratio, 0.98; 95% CI, 0.55 to 1.75) or myocardial infarction (8.1% and 12.0%; hazard ratio, 0.66; 95% CI, 0.43 to 1.00). There was no significant difference in the rate of the primary end point between the PCI group and the registry cohort (13.9% and 15.7%, respectively; hazard ratio, 0.88; 95% CI, 0.55 to 1.39). Relief from angina was more pronounced after PCI than after medical therapy. CONCLUSIONS: In patients with stable coronary artery disease, an initial FFR-guided PCI strategy was associated with a significantly lower rate of the primary composite end point of death, myocardial infarction, or urgent revascularization at 5 years than medical therapy alone. Patients without hemodynamically significant stenoses had a favorable long-term outcome with medical therapy alone. (Funded by St. Jude Medical and others; FAME 2 ClinicalTrials.gov number, NCT01132495 .).

Intra-aortic balloon pump counterpulsation in extensive myocardial infarction with persistent ischemia: The SEMPER FI pilot study.

OBJECTIVES: This study aimed to prospectively investigate intra-aortic balloon pump counterpulsation (IABP) support in large myocardial infarction complicated by persistent ischemia after primary percutaneous coronary intervention (PCI). BACKGROUND: Use of IABP is suggested to be effective by increasing diastolic aortic pressure, thereby improving coronary blood flow. This can only be expected with exhausted coronary autoregulation, typical in acute myocardial infarction complicated by persistent ischemia. In this situation, augmented diastolic pressure is expected to increase myocardial oxygenation. METHODS: One hundred patients with large STEMI complicated by persistent ischemia after primary PCI were randomized to treatment with or without IABP therapy on top of standard care. IABP support was initiated following primary PCI, immediately after inclusion. Primary end point was all-cause mortality, need for (additional) mechanical hemodynamic support, or readmission for heart failure within 6 months. RESULTS: Mean age was 63 ± 10 years, 76% were male. Mean systolic and diastolic blood pressure were 120 ± 25 mmHg and 73 ± 17 mmHg. Mean heart rate was 75 ± 18 mmHg. Before PCI, mean summed ST-deviation was 21 ± 8 mm with only minimal ST-resolution after PCI. One patient in the IABP group reached the primary end point versus four patients in the control group (2% vs. 8%; p = 0.16). After primary PCI, resolution of ST-deviation was significantly more pronounced in the IABP group (73 ± 17%) compared to the control group (56 ± 26%; p < 0.01). CONCLUSIONS: In this pilot study, in patients with large STEMI and persistent ischemia after primary PCI, use of IABP showed a nonsignificant decrease in mortality, necessity for (additional) mechanical hemodynamic support or readmission for heart failure at 6 months, and resulted in more rapid ST-resolution.

Coronary Microcirculation in Aortic Stenosis: Pathophysiology, Invasive Assessment, and Future Directions.

With the increasing prevalence of aortic stenosis (AS) due to a growing elderly population, a proper understanding of its physiology is paramount to guide therapy and define severity. A better understanding of the microvasculature in AS could improve clinical care by predicting left ventricular remodeling or anticipate the interplay between epicardial stenosis and myocardial dysfunction. In this review, we combine five decades of literature regarding microvascular, coronary, and aortic valve physiology with emerging insights from newly developed invasive tools for quantifying microcirculatory function. Furthermore, we describe the coupling between microcirculation and epicardial stenosis, which is currently under investigation in several randomized trials enrolling subjects with concomitant AS and coronary disease. To clarify the physiology explained previously, we present two instructive cases with invasive pressure measurements quantifying coexisting valve and coronary stenoses. Finally, we pose open clinical and research questions whose answers would further expand our knowledge of microvascular dysfunction in AS. These trials were registered with NCT03042104, NCT03094143, and NCT02436655.

Thermodilution-Based Invasive Assessment of Absolute Coronary Blood Flow and Microvascular Resistance: Quantification of Microvascular (Dys)Function?

During the last two decades, there has been a sharp increase in both interest and knowledge about the coronary microcirculation. Since these small vessels are not visible by the human eye, physiologic measurements should be used to characterize their function. The invasive methods presently used (coronary flow reserve (CFR) and index of microvascular resistance (IMR)) are operator-dependent and mandate the use of adenosine to induce hyperemia. In recent years, a new thermodilution-based method for measurement of absolute coronary blood flow and microvascular resistance has been proposed and initial procedural problems have been overcome. Presently, the technique is easy to perform using the Rayflow infusion catheter and the Coroventis software. The method is accurate, reproducible, and completely operator-independent. This method has been validated noninvasively against the current golden standard for flow assessment: Positron Emission Tomography-Computed Tomography (PET-CT). In addition, absolute flow and resistance measurements have proved to be safe, both periprocedurally and at long-term follow-up. With an increasing number of studies being performed, this method has great potential for better understanding and quantification of microvascular disease.

Continuous thermodilution to assess absolute flow and microvascular resistance: validation in humans using [15O]H2O positron emission tomography.

AIMS: Continuous thermodilution is a novel technique to quantify absolute coronary flow and microvascular resistance (MVR). Notably, intracoronary infusion of saline elicits maximal hyperaemia, obviating the need for adenosine. The primary aim of this study was to validate continuous thermodilution in humans by comparing invasive measurements to [15O]H2O positron emission tomography (PET). As a secondary goal, absolute flow and MVR were compared between invasive measurements obtained with and without adenosine. METHODS AND RESULTS: Twenty-five patients underwent coronary computed tomography angiography (CCTA), [15O]H2O PET, and invasive assessment. Absolute coronary flow and MVR were measured in the left anterior descending and left circumflex artery using a dedicated infusion catheter and a temperature/pressure sensor-tipped guidewire. Invasive measurements were performed with and without adenosine. In order to compare invasive flow measurements with PET perfusion, subtending myocardial mass of the investigated vessels was derived from CCTA using the Voronoi algorithm. Invasive and non-invasive measurements of adenosine-induced hyperaemic flow and MVR showed strong correlation (r = 0.91; P < 0.001 for flow and r = 0.85; P < 0.001 for MVR) and good agreement [intraclass correlation coefficient (ICC) = 0.90; P < 0.001 for flow and ICC = 0.79; P < 0.001 for MVR]. Absolute flow and MVR also correlated well between measurements with and without adenosine (r = 0.97; P < 0.001 for flow and r = 0.98; P < 0.001 for MVR) and showed good agreement (ICC = 0.96; P < 0.001 for flow and ICC = 0.98; P < 0.001 for MVR). CONCLUSIONS: Continuous thermodilution is an accurate method to measure absolute coronary flow and MVR, which is evidenced by strong agreement with [15O]H2O PET derived flow and resistance. Absolute flow and MVR correlate highly between invasive measurements obtained with and without adenosine, which confirms that intracoronary infusion of room temperature saline elicits steady-state maximal hyperaemia.

Fractional flow reserve-guided percutaneous coronary intervention vs. medical therapy for patients with stable coronary lesions: meta-analysis of individual patient data.

Aims: To assess the effect of fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) with contemporary drug-eluting stents on the composite of cardiac death or myocardial infarction (MI) vs. medical therapy in patients with stable coronary lesions. Methods and results: We performed a systematic review and meta-analysis of individual patient data (IPD) of the three available randomized trials of contemporary FFR-guided PCI vs. medical therapy for patients with stable coronary lesions: FAME 2 (NCT01132495), DANAMI-3-PRIMULTI (NCT01960933), and Compare-Acute (NCT01399736). FAME 2 enrolled patients with stable coronary artery disease (CAD), while the other two focused on non-culprit lesions in stabilized patients after acute coronary syndrome. A total of 2400 subjects were recruited from 54 sites world-wide with 1056 randomly assigned to FFR-guided PCI and 1344 to medical therapy. The pre-specified primary outcome was a composite of cardiac death or MI. We included data from extended follow-ups for FAME 2 (up to 5.5 years follow-up) and DANAMI-3-PRIMULTI (up to 4.7 years follow-up). After a median follow-up of 35 months (interquartile range 12-60 months), a reduction in the composite of cardiac death or MI was observed with FFR-guided PCI as compared with medical therapy (hazard ratio 0.72, 95% confidence interval 0.54-0.96; P = 0.02). The difference between groups was driven by MI. Conclusion: In this IPD meta-analysis of the three available randomized controlled trials to date, FFR-guided PCI resulted in a reduction of the composite of cardiac death or MI compared with medical therapy, which was driven by a decreased risk of MI.

Fractional Flow Reserve and Quality-of-Life Improvement After Percutaneous Coronary Intervention in Patients With Stable Coronary Artery Disease.

BACKGROUND: Whether the benefit in quality of life (QOL) after percutaneous coronary intervention depends on the severity of the stenosis as determined by fractional flow reserve (FFR) remains unknown. This study sought to investigate the relationship between FFR values and improvement in QOL. METHODS: From the FAME 1 and 2 trials (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation), we identified 706 stable patients with coronary artery disease who had at least 1 lesion with an FFR≤0.80 that was treated with percutaneous coronary intervention and 185 patients with coronary artery disease who had no lesion with an FFR≤0.80 and were treated medically who served as a reference group. QOL was assessed by the European Quality of Life-5 Dimensions index at baseline, 1 month, and 1 year. We assessed the relationship between QOL improvement (defined as the change in European Quality of Life-5 Dimensions index from baseline) and FFR as a continuous value and according to abnormal FFR tertile. RESULTS: QOL improved significantly after percutaneous coronary intervention in each abnormal FFR tertile, whereas it did not change in the reference group. The lowest abnormal FFR subgroup had the greatest improvement in QOL at 1 month ( P<0.001). In mixed-effects models for repeated measures, lower FFR ( P=0.002 for 1 month and 0.049 for 1 year), greater delta FFR ( P=0.021 for 1 month and 0.025 for 1 year), and higher angina class ( P=0.001 for 1 month and <0.001 for 1 year) were associated with the greatest magnitude of QOL improvement at both 1 month and 1 year. CONCLUSIONS: Among patients with stable coronary artery disease, FFR and angina severity predict QOL improvement after percutaneous coronary intervention. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifiers: NCT00267774 and NCT01132495.

Clinical Outcomes and Cost-Effectiveness of Fractional Flow Reserve-Guided Percutaneous Coronary Intervention in Patients With Stable Coronary Artery Disease: Three-Year Follow-Up of the FAME 2 Trial (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation).

BACKGROUND: Previous studies found that percutaneous coronary intervention (PCI) does not improve outcome compared with medical therapy (MT) in patients with stable coronary artery disease, but PCI was guided by angiography alone. FAME 2 trial (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) compared PCI guided by fractional flow reserve with best MT in patients with stable coronary artery disease to assess clinical outcomes and cost-effectiveness. METHODS: A total of 888 patients with stable single-vessel or multivessel coronary artery disease with reduced fractional flow reserve were randomly assigned to PCI plus MT (n=447) or MT alone (n=441). Major adverse cardiac events included death, myocardial infarction, and urgent revascularization. Costs were calculated on the basis of resource use and Medicare reimbursement rates. Changes in quality-adjusted life-years were assessed with utilities determined by the European Quality of Life-5 Dimensions health survey at baseline and over follow-up. RESULTS: Major adverse cardiac events at 3 years were significantly lower in the PCI group compared with the MT group (10.1% versus 22.0%; P<0.001), primarily as a result of a lower rate of urgent revascularization (4.3% versus 17.2%; P<0.001). Death and myocardial infarction were numerically lower in the PCI group (8.3% versus 10.4%; P=0.28). Angina was significantly less severe in the PCI group at all follow-up points to 3 years. Mean initial costs were higher in the PCI group ($9944 versus $4440; P<0.001) but by 3 years were similar between the 2 groups ($16 792 versus $16 737; P=0.94). The incremental cost-effectiveness ratio for PCI compared with MT was $17 300 per quality-adjusted life-year at 2 years and $1600 per quality-adjusted life-year at 3 years. The above findings were robust in sensitivity analyses. CONCLUSIONS: PCI of lesions with reduced fractional flow reserve improves long-term outcome and is economically attractive compared with MT alone in patients with stable coronary artery disease. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01132495.

Feasibility and safety of jailed-pressure wire technique using durable optical fiber pressure wire for intervention of coronary bifurcation lesions.

OBJECTIVES: The objective was to evaluate the safety, feasibility, and accuracy of the jailed-pressure wire technique using a durable optical fiber-based pressure wire with high-pressure dilatation using a non-compliant balloon after main vessel stenting. BACKGROUND: Fractional flow reserve (FFR) information can help interventionists determine whether they should treat a jailed-side branch (SB). However, re-crossing a pressure wire into a jailed-SB is sometimes technically difficult. METHODS: Fifty-one consecutive lesions from 48 patients who underwent the jailed-pressure wire technique were retrospectively investigated. The primary endpoint was complication rate and secondary endpoints included success rate of FFR measurement, incidence of wire disruption, and final drift rate. The usability of FFR for percutaneous coronary intervention of coronary bifurcation lesion was also evaluated. RESULTS: Median age of the patients was 69 years and 80.4% were men. The most frequent underlying disease was stable angina (70.6%) and 68.6% were type B2 lesions. Our main findings were: the procedure was performed successfully in all cases without any complications or wire disruption, FFR could be measured without significant final drift in 95.9% of cases, and FFR measurements helped interventionists determine whether to perform a final kissing balloon dilatation in 49.0% cases. CONCLUSIONS: The jailed-pressure wire technique using a durable optical fiber-based pressure wire with high-pressure post-dilatation maneuver was safe, feasible, and accurate.

Predictive factors of discordance between the instantaneous wave-free ratio and fractional flow reserve.

OBJECTIVES: To identify clinical, angiographic and hemodynamic predictors of discordance between instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR). BACKGROUND: The iFR was found to be non-inferior to the gold-standard FFR for guiding coronary revascularization, although it is discordant with FFR in 20% of cases. A better understanding of the causes of discordance may enhance application of these indices. METHODS: Both FFR and iFR were measured in the prospective multicenter CONTRAST study. Clinical, angiographic and hemodynamic variables were compared between patients with concordant values of FFR and iFR (cutoff ≤0.80 and ≤0.89, respectively). RESULTS: Out of the 587 patients included, in 466 patients (79.4%) FFR and iFR agreed: both negative, n = 244 (41.6%), or positive, n = 222 (37.8%). Compared with FFR, iFR was negative discordant (FFR+/iFR-) in 69 (11.8%) patients and positive discordant (FFR-/iFR+) in 52 (8.9%) patients. On multivariate regression, stenosis location (left main or proximal left anterior descending) (OR: 3.30[1.68;6.47]), more severe stenosis (OR: 1.77[1.35;2.30]), younger age (OR: 0.93[0.90;0.97]), and slower heart rate (OR: 0.59[0.42;0.75]) were predictors of a negative discordant iFR. Absence of a beta-blocker (OR: 0.41[0.22;0.78]), older age (OR: 1.04[1.00;1.07]), and less severe stenosis (OR: 0.69[0.53;0.89]) were predictors of a positive discordant iFR. CONCLUSIONS: During iFR acquisition, stenosis location, stenosis degree, heart rate, age and use of beta blockers influence concordance with FFR and should be taken into account when interpreting iFR.

Pressure gradient vs. flow relationships to characterize the physiology of a severely stenotic aortic valve before and after transcatheter valve implantation.

Aims: Echocardiography and tomographic imaging have documented dynamic changes in aortic stenosis (AS) geometry and severity during both the cardiac cycle and stress-induced increases in cardiac output. However, corresponding pressure gradient vs. flow relationships have not been described. Methods and results: We recruited 16 routine transcatheter aortic valve implantations (TAVI's) for graded dobutamine infusions both before and after implantation; 0.014″ pressure wires in the aorta and left ventricle (LV) continuously measured the transvalvular pressure gradient (ΔP) while a pulmonary artery catheter regularly assessed cardiac output by thermodilution. Before TAVI, ΔP did not display a consistent relationship with transvalvular flow (Q). Neither linear resistor (median R2 0.16) nor quadratic orifice (median R2 < 0.01) models at rest predicted stress observations; the severely stenotic valve behaved like a combination. The unitless ratio of aortic to left ventricular pressures during systolic ejection under stress conditions correlated best with post-TAVI flow improvement. After TAVI, a highly linear relationship (median R2 0.96) indicated a valid valve resistance. Conclusion: Pressure loss vs. flow curves offer a fundamental fluid dynamic synthesis for describing aortic valve pathophysiology. Severe AS does not consistently behave like an orifice (as suggested by Gorlin) or a resistor, whereas TAVI devices behave like a pure resistor. During peak dobutamine, the ratio of aortic to left ventricular pressures during systolic ejection provides a 'fractional flow reserve' of the aortic valve that closely approximates the complex, changing fluid dynamics. Because resting assessment cannot reliably predict stress haemodynamics, 'valvular fractional flow' warrants study to explain exertional symptoms in patients with only moderate AS at rest.

Fractional flow reserve and pressure-bounded coronary flow reserve to predict outcomes in coronary artery disease.

AIMS: Fractional flow reserve (FFR) has proven to its prognostic and therapeutic value. However, the additive prognostic value of coronary flow reserve (CFR) remains unclear. This study sought to investigate the clinical utility of combined FFR and CFR measurements to predict outcomes. METHODS AND RESULTS: Using the prospective, multicentre Interventional Cardiology Research Incooperation Society-FFR registry, a total of 2088 lesions from 1837 patients were included in this substudy. Based on baseline and hyperaemic pressure gradients, we computed physiologic limits of CFR [the so called pressure-bounded (pb) CFR] and classified lesions as low (<2) or high (≥2). The primary endpoint was major adverse cardiac events (MACE, a composite of cardiac death, myocardial infarction, and revascularization) analysed on a per-patient basis. During a median follow-up of 1.9 years (inter-quartile range: 1.0-3.0 years), MACE occurred in 5.7% of patients with FFR ≤0.80 vs. 2.8% of patients with FFR >0.80 [adjusted hazard ratio (aHR): 2.15, 95% confidence interval (CI): 1.19-3.89; P = 0.011. In contrast, the incidence of MACE did not differ between patients with pb-CFR < 2 vs. pb-CFR ≥ 2 (4.2% vs. 4.2%; aHR: 0.98, CI: 0.60 to 1.58; P = 0.92). Incorporation of FFR significantly improved model prediction of MACE (global χ2 38.8-48.1, P = 0.002). However, pb-CFR demonstrated no incremental utility to classify outcomes (global χ2 48.1-48.2, P > 0.99). CONCLUSIONS: In this large, prospective registry of over 2000 coronary lesions, FFR was strongly associated with clinical outcomes. In contrast, a significant association between pb-CFR and clinical events could not be determined and adding knowledge of pb-CFR did not improve prognostication over FFR alone.