Search Results (186)

Background/Objectives: The diagnostic value of Quantitative Flow Ratio (QFR) with respect to Fractional Flow Reserve (FFR) in real-world settings is not well described, and neither are the factors influencing the bias of QFR versus FFR well understood. The learning curve associated with QFR calculation has not been thoroughly investigated. Hence, we sought to evaluate the association between the QFR and FFR, to investigate the influence of clinical parameters on both values and their difference, and to analyze the learning curve associated with QFR measurement in a real-world setting. Methods: All patients who underwent FFR and QFR measurements in 2023 at our tertiary-care center were included. The bias was characterized using a Bland–Altman plot and multivariable regression was used to uncover its potential predictors. Results: QFR calculation was successful in 73% of 595 patients with 778 vessels with FFR measurement results. Median bias of QFR was 0.011, but in 7% of the cases, the difference between the two exceeded 0.10. A good correlation was found between the two indices. Receiver operating characteristic curve analysis showed that the area under the curve of QFR for predicting FFR ≤ 0.80 was 0.912. FFR and QFR values were lower in the left anterior descending artery; acute coronary syndrome indication was associated with higher QFR values. Right coronary artery localization was associated with a greater bias of QFR, whereas female gender and aortic stenosis were associated with a lower bias of QFR. Both measurement time and bias decreased in a non-linear fashion with increasing experience. Conclusions: Clinical and angiographic factors affect the bias of QFR versus FFR. QFR has a short learning curve with growing experience leading to shorter measurement time and less bias. Full article

Percutaneous Coronary Intervention (PCI) has advanced significantly with the incorporation of imaging and physiology assessment techniques. Fractional Flow Reserve (FFR) and Non-Hyperemic Pressure indices (NHPIs) provide information regarding the functional significance of coronary lesions, while Intravascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT) enhance anatomical characterization and guide stent implantation. This review explores the implementation of physiology- and imaging-guided strategies in clinical practice, comparing their efficacy and limitations. Novel technologies now allow for physiology estimation without hyperemic agents, and hybrid techniques, such as OCT-derived FFR, are increasingly integrated into clinical practice. These approaches offer the combined advantages of functional assessment and detailed anatomical imaging. Full article

A revolutionary non-invasive method for the thorough evaluation of coronary artery disease (CAD) is fractional flow reserve (FFR) obtained from coronary computed tomography angiography (CCTA). Computed tomography-derived FFR (FFR_CT) assesses both the anatomical and functional significance of coronary lesions simultaneously by utilizing sophisticated computational models, including computational fluid dynamics, machine learning (ML), and Artificial Intelligence (AI) methods. The technological development, validation research, clinical uses, and real-world constraints of FFR_CT are compiled in this review. Large multicenter trials and registries consistently show that FFR_CT is a reliable gatekeeper to invasive coronary angiography (ICA) and increases diagnostic accuracy significantly when compared to coronary Computed Tomography Angiography (CTA) alone, especially in patients with intermediate-risk anatomy. Additionally, FFR_CT has demonstrated benefits in populations with in-stent restenosis (ISR) and in virtual procedural planning. Notwithstanding its advantages, the technique still requires high-quality imaging, and its practical application is constrained by expenses, processing requirements, and image distortions. Continuous developments in automation and deep learning should improve accessibility, effectiveness, and workflow integration in clinical settings. FFR_CT is expected to become more and more important in the individualized treatment of CAD by minimizing unnecessary invasive procedures and improving patient selection for revascularization. Full article

Fractional flow reserve (FFR) is a standard physiological index for guiding coronary revascularization, with a threshold of >0.80 typically used to defer intervention. However, due to its distinct anatomical and physiological features, the left anterior descending artery (LAD) often exhibits lower FFR values than non-LAD vessels for lesions of similar angiographic severity. These vessel-specific differences raise concerns about applying a uniform FFR cutoff across all coronary territories. Observational studies indicate that LAD lesions deferred at an FFR of 0.80 may have similar or better outcomes than non-LAD lesions do. LAD lesions also tend to show lower post-percutaneous coronary intervention FFR values, suggesting that vessel specific target thresholds may be more prognostically appropriate. Additionally, some evidence suggests that instantaneous wave-free ratio may offer greater prognostic value than FFR, specifically in LAD lesions, a trend not consistently seen in other arteries. In patients with acute myocardial infarction and multivessel disease, the prognostic relevance of non-culprit lesion FFR may vary by coronary territory, particularly in the LAD. This review outlines the physiological rationale and clinical evidence for vessel-specific interpretation of FFR, with a focus on the LAD, and explores its potential clinical implications and limitations. Full article

Advances in plaque imaging have transformed cardiovascular diagnostics through detailed characterization of atherosclerotic plaques beyond traditional stenosis assessment. This review outlines the clinical applications of varying modalities, including dual-layer spectral CT, photon-counting CT, dual-energy CT, and CT-derived fractional flow reserve (CT-FFR). These technologies offer improved spatial resolution, tissue differentiation, and functional assessment of coronary lesions. Additionally, artificial intelligence has emerged as a powerful tool to automate plaque detection, quantify burden, and refine risk prediction. Collectively, these innovations provide a more comprehensive approach to coronary artery disease evaluation and support personalized management strategies. Full article

Optical Coherence Tomography (OCT) is a further light-based intravascular imaging modality and provides a high-resolution, cross-sectional view of coronary arteries. It has a useful anatomic and increasingly physiological evaluation in light of coronary artery disease (CAD). This review provides a critical examination of the increased application of the OCT in assessing coronary artery physiology, beyond its initial mainstay application in anatomical imaging. OCT provides precise information on plaque morphology, which can help identify vulnerable plaques, and is most important in informing percutaneous coronary interventions (PCIs), including implanting a stent and optimizing it. The combination of OCT and functional measurements, such as optical flow ratio and OCT-based fractional flow reserve (OCT-FFR), permits a more complete assessment of coronary stenoses, which may provide increased diagnostic accuracy and better revascularization decision-making. The recent developments in OCT technology have also enhanced the accuracy in the measurement of coronary functions. The innovations may support the optimal treatment of patients as they provide more personalized and individualized treatment options; however, it is critical to recognize the limitations of OCT and distinguish between the hypothetical advantages and empirical outcomes. This review evaluates the existing uses, technological solutions, and future trends in OCT-based physiological imaging and evaluation, and explains how such an advancement will be beneficial in the treatment of CAD and gives a fair representation concerning other imaging applications. Full article

Coronary computed tomography angiography (CCTA) has emerged as the leading noninvasive imaging modality for the assessment of coronary artery disease (CAD), offering high-resolution visualization of the coronary anatomy and plaque characterization. The development of fractional flow reserve derived from CCTA (FFR-CT) has further transformed the diagnostic landscape by enabling the simultaneous evaluation of both anatomical stenosis and lesion-specific ischemia. FFR-CT has demonstrated diagnostic accuracy comparable to invasive FFR. The combined use of CCTA and FFR-CT is now pivotal in a broad range of clinical scenarios, including the evaluation of stable and acute chest pain, assessment of high-risk and complex plaque features, and preoperative planning. As evidence continues to mount, CCTA and FFR-CT are positioned to become the primary gatekeepers to the cardiac catheterization laboratory, potentially reducing the number of unnecessary invasive procedures. This review highlights the growing clinical utility of FFR-CT, its integration with advanced plaque imaging, and the future potential of these technologies in redefining the management of CAD, while also acknowledging current limitations, including image quality requirements, cost, and access. Full article

(1) Background: Our aim was to evaluate the diagnostic performance of combined coronary computed tomography angiography (CCTA) and dynamic CT myocardial perfusion imaging (CT-MPI) for detecting hemodynamically significant coronary artery disease (CAD) in patients with intermediate pretest probability. (2) Methods: Patients with an intermediate pretest probability of CAD were retrospectively enrolled. All patients underwent CCTA and dynamic CT-MPI using a third-generation dual-source CT scanner prior to invasive coronary angiography (ICA). Anatomically significant stenosis was defined as ≥50% luminal narrowing on both CCTA and ICA. Fractional flow reserve (FFR) was performed during ICA in selected cases. Hemodynamically significant CAD was defined per vessel as FFR ≤ 0.80, angiographic stenosis ≥70%, or having undergone revascularization. The diagnostic performance of CCTA alone and CCTA combined with CT-MPI was compared against this reference standard. (3) Results: Seventy-four patients (mean age, 66.8 ± 11.1 years; 59 men) were included. The median coronary calcium score was 508.5 Agatston units (interquartile range: 147–1173). ICA and CCTA detected anatomically significant stenoses in 137 (61.7%) and 146 (65.8%) coronary vessels, respectively, and in 62 (83.8%) and 71 (95.9%) patients, respectively. Hemodynamically significant stenosis was present in 56 patients (76%) and 99 vessels (45%). On a per-vessel basis, CCTA alone yielded a sensitivity of 96.7%, specificity of 60.3%, positive predictive value (PPV) of 64.4%, and negative predictive value (NPV) of 96.1%. Combined CCTA and CT-MPI demonstrated a sensitivity of 90.1%, specificity of 84.3%, PPV of 82.7%, and NPV of 91.1%. The area under the receiver operating characteristic curve improved from 0.787 (95% confidence interval: 0.73–0.84) for CCTA to 0.872 (95% confidence interval: 0.82–0.91) for the combined approach (p < 0.05). The median total radiation dose for both CCTA and CT-MPI was 8.05 mSv (interquartile range: 6.71–11.0). (4) Conclusions: In patients with intermediate pretest probability of CAD, combining CCTA with dynamic CT-MPI significantly enhances the diagnostic performance for identifying hemodynamically significant coronary stenosis compared to CCTA alone. Full article

Cardiac allograft vasculopathy (CAV) is a leading cause of allograft dysfunction and failure. CAV prevention, early detection, and management are essential to increasing allograft survival. In this comprehensive review, we discuss various invasive and non-invasive modalities that are being utilized for CAV detection. Invasive coronary angiography provides a visualization of vascular anatomy but is limited in detecting the microvasculature and diffuse and early structural changes. The addition of intracoronary assessment techniques, including intravascular ultrasound, optical coherence tomography, and coronary flow reserve assessment, offer(s) superior sensitivity in identifying CAV. Non-invasive imaging modalities, such as cardiac magnetic resonance imaging, computed tomography angiography, and positron emission tomography, provide complementary insights into CAV with myocardial perfusion and allograft function while reducing procedural risks. Our aim is to guide clinicians in selecting appropriate imaging strategies tailored to individual recipients, to improve detection, monitoring, and outcomes in CAV. Full article

Background: Synchronous computation of coronary angiography-derived fractional flow reserve (CAG-FFR) and coronary angiography-derived index of microcirculatory resistance (CAG-IMR) is a novel coronary angiography-based method for on-site assessment of suspected myocardial ischemia in patients with coronary artery disease (CAD). Methods: This trial is a prospective, multicenter, controlled study designed to assess the diagnostic performance of CAG-FFR and CAG-IMR in patients with suspected myocardial ischemia using wire-based FFR and IMR as reference standards. The functional parameters were calculated using a reduced order computational fluid dynamics solver that incorporates thrombolysis in myocardial infarction (TIMI) frame count and aortic pressure recorded by a disposable invasive pressure sensor. Results: CAG-FFR was computed in 325 patients, demonstrating a patient-level diagnostic accuracy of 95.4%, sensitivity of 95.9%, and specificity of 95.1%. The area under the receiver operating characteristic curve (AUC) of CAG-FFR was 0.977. Patient-specific aortic pressure adoption significantly improved the accuracy of CAG-FFR in the “gray zone” compared to fixed-pressure models. In addition, CAG-IMR was successfully computed in 180 patients, showing a patient-level diagnostic accuracy of 95.5%, sensitivity of 96.4%, and specificity of 95.2%. The AUC of CAG-IMR in diagnosing abnormal coronary microcirculatory dysfunction was 0.973. Conclusions: Synchronous computation of CAG-FFR and CAG-IMR demonstrated higher feasibility and excellent diagnostic accuracy compared to wire-based FFR and IMR, highlighting its clinical potential for CAD evaluation. Full article

Background and Objectives: Up to 40% of patients undergoing a coronary angiogram due to angina pectoris have no obstructive coronary artery disease, also known as angina with non-obstructive coronary arteries (ANOCA). ANOCA is associated with significant impairment in patients’ quality of life, increased risk of myocardial infarction and all-cause mortality. Approximately 25% of patients with ANOCA have persisting symptoms despite optimal medical therapy. There is a lack of in-depth knowledge regarding tailored treatment for patients with ANOCA due to a scarcity of trials designed to assess the effect of treatment modalities. The aim of this systematic review and meta-analysis is to give clinicians an overview of the efficacy of current treatment modalities for patients with ANOCA. Methods: PudMed/MEDLINE, Embase, the Cochrane Library and clinical trial registries were searched for randomised controlled and cohort studies regarding treatment modalities for ANOCA. The main outcome was change in angina pectoris frequency for each treatment modality. Secondary outcomes included changes in exercise capacity, quality of life, Canadian Cardiovascular Society (CCS) class, coronary flow reserve (CFR) and survival. Results: In total, 80 studies were included and used in the meta-analysis, of which ten studies met the current definition of ANOCA. Angina pectoris frequency improved significantly in the majority of the treatment modalities, with neuromodulation resulting in −3.35 standardised mean difference (SMD) (95% CI: −5.13; −1.56), trimetazidine in −1.74 SMD (−2.63; −0.85), traditional Chinese medicine in −1.55 SMD (−2.36; −0.75), beta-blockers in −1.32 SMD (−1.88; −0.77), enhanced external counterpulsation in −1.27 SMD (−2.04; −0.49), stem cell therapy in −1.04 SMD (−1.51; −0.57), lifestyle interventions in −0.86 SMD (−1.15; −0.57), RAAS-inhibitors in −0.83 SMD (−1.31; −0.35) and calcium channel blockers in −0.64 SMD (−0.92; −0.35). Conclusions: This meta-analysis into treatment modalities for patients with ANOCA shows a significant improvement in angina pectoris frequency in the majority of included treatment modalities. However, these results should be interpreted cautiously, as only ten of the studies included in the meta-analysis meet the current definition of ANOCA. This review underlines the importance of undertaking new studies with existing treatment modalities to determine the efficacy in patients with ANOCA. Full article

Coronary microvascular disease (CMVD) is not an uncommon complication after acute myocardial infarction (AMI), independent of prompt revascularization. It is a serious yet underdiagnosed disease that has a major impact on patient outcomes. Even when the infarct-related artery is successfully revascularized, a significant percentage of patients still have compromised microvascular circulation, which is linked to higher cardiovascular mortality and hospitalization for heart failure. The well-known invasive methods, such as the index of microvascular resistance (IMR) and the coronary flow reserve (CFR), have been considered as gold standards. However, they are constrained by their hazards and complexity. Non-invasive techniques, such as echocardiography Doppler for CFR assessment, positron emission tomography (PET), cardiac magnetic resonance imaging (CMR), and some other techniques provide alternatives, but their accessibility, cost and implementation during the peri-AMI period raise obstacles to their wider use. This review highlights both invasive and non-invasive modalities as it examines the diagnostic methods and prognostic significance of CMVD development early after AMI. Enhancing long-term results in this high-risk population requires a thorough understanding of pathophysiology and a commitment to larger diagnostic and prognostic studies for CMVD. Full article

Background and Objectives: Nonischemic cardiomyopathies comprise a wide spectrum of heart muscle disorders characterized by different morphological, functional, and tissue abnormalities. Cardiovascular magnetic resonance (CMR) represents the gold standard imaging modality for assessing cardiac morphology, systolic function, and tissue characterization, thereby aiding in early diagnosis, precise phenotyping, and tailored treatment. The aim of this review is to provide an up-to-date overview of CMR techniques for studying myocardial perfusion and their applications to nonischemic cardiomyopathy, not only to rule out an underlying ischemic aetiology but also to investigate the pathophysiological characteristics of microcirculatory dysfunction in these patients. Materials and Methods: We performed a structured review of the literature focusing on first-pass gadolinium perfusion sequences, stress protocols, and emerging pixel-wise perfusion mapping approaches. Studies were selected to illustrate the methods for image acquisition, post-processing, and quantification of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR), as well as to highlight associations with clinical endpoints. Results: First-pass CMR perfusion imaging reliably detects diffuse and regional microvascular dysfunction across cardiomyopathies. Semi-quantitative parameters (e.g., upslope, MPRI) and quantitative MBF mapping (mL/g/min) have demonstrated that impaired perfusion correlates with disease severity, extent of fibrosis, and adverse outcomes, including heart failure hospitalization, arrhythmias, and mortality. Novel automated pixel-wise mapping enhances reproducibility and diagnostic accuracy, distinguishing coronary microvascular dysfunction from balanced three-vessel disease. Microvascular dysfunction—present in approximately 50–60% of dilated cardiomyopathy (DCM), 40–80% of hypertrophic cardiomyopathy (HCM), and >95% of cardiac amyloidosis (CA) patients—has emerged as a key driver of adverse outcomes. Perfusion defects appear early, often preceding overt hypertrophy or fibrosis, and provide incremental prognostic value beyond conventional CMR metrics. Conclusions: CMR represents a powerful tool for detecting myocardial perfusion abnormalities in nonischemic cardiomyopathies, improving phenotyping, risk stratification, and personalized management. Further standardization of quantitative perfusion techniques will facilitate broader clinical adoption. Full article

The understanding of coronary artery disease is evolving, with more attention given currently to the microcirculation compartment. Coronary microvascular dysfunction (CMD) is defined by any structural or functional alteration of the coronary microcirculation, and is prevalent in current clinical practice, being associated with pejorative cardiovascular prognosis. CMD can exist by itself as primary microvascular angina, or in association with a variety of cardiovascular diseases. On the other hand, fractional flow reserve (FFR) represents the gold standard for estimating the hemodynamic impact of moderate coronary artery stenosis, and as such guiding coronary revascularization in clinical practice. The fundamental clinical trials that introduced and validated the use of FFR in current clinical practice were published before acquiring more in-depth knowledge on CMD and the impact it can have on FFR measurements. However, in the setting of CMD, studies have shown that FFR can underestimate the severity of coronary stenosis. In addition, recent findings underline the limitations of FFR to guide revascularization in terms of clinical outcome in specific conditions associated with CMD, such as acute coronary syndrome or multivessel coronary artery disease. As such, new research efforts must be made to investigate the reliability of FFR or to reposition its use in guiding coronary revascularization in the context of CMD, in order to define the clinical value of FFR in this particular setting. Full article

Coronary microvascular dysfunction (CMD) is a key contributor to myocardial ischemia and adverse cardiovascular outcomes, particularly in individuals with metabolic disorders such as type 2 diabetes (T2D). While conventional therapies primarily target epicardial coronary disease, effective treatments for CMD remain limited. Glucagon-like peptide-1 receptor (GLP-1R) agonists have emerged as promising agents with cardiovascular benefits extending beyond glycemic control. Preclinical and clinical evidence suggests that GLP-1R activation enhances coronary microvascular function through mechanisms including improved endothelial function, increased nitric oxide bioavailability, attenuation of oxidative stress, and reduced vascular inflammation. Moreover, GLP-1R agonists have been shown to improve myocardial blood flow, myocardial perfusion reserve, and coronary endothelial function, particularly in high-risk populations. Despite these promising findings, inconsistencies remain across studies due to variability in patient populations, study designs, and imaging methodologies. This review summarizes current evidence on the role of GLP-1R agonists in myocardial perfusion, bridging mechanistic insights with clinical outcomes. Further large-scale, well-designed trials are needed to clarify their long-term impact on coronary microcirculation and explore their potential as targeted therapies for CMD. Full article