Optimizing Non-Invasive Detection of Coronary Artery Disease and Effects of Advanced Interventional Techniques for Patients with Stable Coronary Artery Disease:It is All about Myocardial Perfusion

The aim of this thesis was to (1) further optimize non-invasive detection of hemodynamically significant coronary artery disease (CAD) with coronary computed tomography angiography (CCTA) and myocardial perfusion imaging (MPI) and to examine (2) the effect of implantation of the bioresorbable vascular scaffold (BVS) and (3) chronic total occlusion percutaneous coronary intervention (CTO PCI). Part I showed that angiographic characteristics such as volumetric measures as well as morphological aspects of atherosclerosis as assessed by CCTA are of interest when considering the hemodynamic consequences of atherosclerosis. These findings add to luminal stenosis grading alone and aid in increasing the diagnostic accuracy of CCTA to predict hemodynamically significant CAD determined by invasive FFR. The main results of Part II indicate that implantation of the BVS is feasible however no benefit with regard to myocardial perfusion is observed during hyperemia or cold pressor testing. These findings do not support the use of BVS instead of metallic DES, especially since large randomized trials have illustrated that there is an increased risk in scaffold thrombosis during the first three years. Still, long-term outcome (>3 years) has yet to become available. The results of the studies in Part III indicate that the vast majority of patients with a CTO have significantly impaired myocardial perfusion with great effect of successful CTO PCI on recovery of myocardial perfusion and decrease of ischemic burden. Patient selection for CTO PCI should be based on expected patient benefit rather than lesion complexity

Development and validation of a quantitative coronary CT Angiography model for diagnosis of vessel-specific coronary ischemia

Background: Noninvasive stress testing is commonly used for detection of coronary ischemia but possesses variable accuracy and may result in excessive health care costs. Objectives: This study aimed to derive and validate an artificial intelligence-guided quantitative coronary computed tomography angiography (AI-QCT) model for the diagnosis of coronary ischemia that integrates atherosclerosis and vascular morphology measures (AI-QCTISCHEMIA) and to evaluate its prognostic utility for major adverse cardiovascular events (MACE). Methods: A post hoc analysis of the CREDENCE (Computed Tomographic Evaluation of Atherosclerotic Determinants of Myocardial Ischemia) and PACIFIC-1 (Comparison of Coronary Computed Tomography Angiography, Single Photon Emission Computed Tomography [SPECT], Positron Emission Tomography [PET], and Hybrid Imaging for Diagnosis of Ischemic Heart Disease Determined by Fractional Flow Reserve) studies was performed. In both studies, symptomatic patients with suspected stable coronary artery disease had prospectively undergone coronary computed tomography angiography (CTA), myocardial perfusion imaging (MPI), SPECT, or PET, fractional flow reserve by CT (FFRCT), and invasive coronary angiography in conjunction with invasive FFR measurements. The AI-QCTISCHEMIA model was developed in the derivation cohort of the CREDENCE study, and its diagnostic performance for coronary ischemia (FFR ≤0.80) was evaluated in the CREDENCE validation cohort and PACIFIC-1. Its prognostic value was investigated in PACIFIC-1. Results: In CREDENCE validation (n = 305, age 64.4 ± 9.8 years, 210 [69%] male), the diagnostic performance by area under the receiver-operating characteristics curve (AUC) on per-patient level was 0.80 (95% CI: 0.75-0.85) for AI-QCTISCHEMIA, 0.69 (95% CI: 0.63-0.74; P < 0.001) for FFRCT, and 0.65 (95% CI: 0.59-0.71; P < 0.001) for MPI. In PACIFIC-1 (n = 208, age 58.1 ± 8.7 years, 132 [63%] male), the AUCs were 0.85 (95% CI: 0.79-0.91) for AI-QCTISCHEMIA, 0.78 (95% CI: 0.72-0.84; P = 0.037) for FFRCT, 0.89 (95% CI: 0.84-0.93; P = 0.262) for PET, and 0.72 (95% CI: 0.67-0.78; P < 0.001) for SPECT. Adjusted for clinical risk factors and coronary CTA-determined obstructive stenosis, a positive AI-QCTISCHEMIA test was associated with an HR of 7.6 (95% CI: 1.2-47.0; P = 0.030) for MACE. Conclusions: This newly developed coronary CTA-based ischemia model using coronary atherosclerosis and vascular morphology characteristics accurately diagnoses coronary ischemia by invasive FFR and provides robust prognostic utility for MACE beyond presence of stenosis.info:eu-repo/semantics/acceptedVersio

Myocardial perfusion imaging with PET

Noninvasive assessment of coronary artery disease remains a challenging task, with a large armamentarium of diagnostic modalities. Myocardial perfusion imaging (MPI) is widely used for this purpose whereby cardiac positron emission tomography (PET) is considered the gold standard. Next to relative radiotracer distribution, PET allows for measurement of absolute myocardial blood flow. This quantification of perfusion improves diagnostic accuracy and prognostic value. Cardiac hybrid imaging relies on the fusion of anatomical and functional imaging using coronary computed tomography angiography and MPI, respectively, and provides incremental value as compared with either stand-alone modality

Percutaneous coronary intervention of chronic total occlusions: When and how to treat

Chronic coronary total occlusions (CTO) are diagnosed in up to 20% of patients with coronary artery disease and have a detrimental effect on patients' quality of life and long-term prognosis. The exponential developments in CTO percutaneous coronary intervention (PCI) equipment, recanalization techniques, and operator expertise have been merged into the hybrid approach that represents a percutaneous revascularization algorithm for treating CTOs and has led to technical success over 90% at experienced centers. Therefore, patient selection for CTO PCI should be focused on anticipated patient benefit in terms of health status and long-term prognosis rather than coronary anatomic complexity. Table of contents: This review will provide an overview of the clinical presentation and characteristics of patients with a CTO and will discuss the essential needs toward judicious patient selection for percutaneous CTO revascularization according to contemporary knowledge. Furthermore, the current high standard revascularization techniques in dedicated CTO PCI will be discussed

Why, when and how to assess ischemia and viability in patients with chronic total occlusions

Currently, international guidelines recommend the evaluation of ischemic symptoms, as well as the extent of ischemia and the presence of viability, prior to referring patients with stable coronary artery disease, including chronic total occlusion (CTO), for revascularization. A few randomized trials and numerous observational studies have tried to determine the value of ischemia-driven and viability-driven revascularization, but demonstrated contradicting findings. The present review will focus on the current knowledge regarding ischemia and viability testing in patients with a CTO. The evidence and rationale to assess ischemia and viability, next to the clinical workup for CTO revascularization in clinical practice, will be discussed. In addition, an overview of available noninvasive imaging modalities to assess the presence and extent of ischemia and viability will be provided

Comparative diagnostic accuracy of dual-energy CT myocardial perfusion imaging by monochromatic energy versus material decomposition methods

PURPOSE: To compare the diagnostic value of monochromatic and material decomposition (MD) dual- energy computed tomography (DECT) imaging for the evaluation of ischemia. METHODS: Patients with suspected coronary artery disease underwent rest-stress DECT and SPECT perfusion imaging. DECT images were reconstructed between 40 and 140keV and through MD of iodine/muscle. RESULTS: MD and monochromatic imaging had a sensitivity, specificity, negative predictive, positive predictive value, and accuracy of 89%, 40%, 67%, 73% and 71%; and 91%, 67%, 67%, 91% and 86%, respectively (p=0.05). CONCLUSION: DECT using monochromatic energy displayed a non-significantly higher diagnostic accuracy for myocardial ischemia as compared with DECT MD

FRACTIONAL FLOW RESERVE BUT NOT INSTANTANEOUS WAVE-FREE RATIO DETECTS PLAQUE VULNERABILITY

Background: Fractional fow reserve (FFR) is, next to lesion severity, affected by plaque vulnerability as assessed by coronary computed tomography angiography (CCTA) and associated with imminent acute coronary syndromes. Instantaneous wave-free ratio (iFR) has recently emerged as an alternative for FFR to interrogate coronary lesions for ischemia. It is, however, unknown whether vasodilator free assessment with iFR is associated with plaque stability similarly as FFR. The current substudy of the PACIFIC trial explores the impact of CCTA derived unfavorable plaque features on both hyperemic and non-hyperemic fow indices in order to detect vulnerable plaques. Methods: Of 119 patients (62% men, age 58 ± 8.6 years) with suspected coronary artery disease, 257 vessels were prospectively evaluated. Each patient underwent 256-slice CCTA to assess stenosis severity and plaque features (positive remodeling (PR), low attenuation plaque (LAP), spotty calcifcation (SC) and napkin ring sign (NRS)), as well as intracoronary pressure measurements (FFR, iFR, resting Pd/Pa and pressure ratio during adenosine within the wave-free period (iFRa)). CCTA derived plaque characteristics were related to these invasive pressure measurements. Results: Atherosclerotic plaques were present in 170 (66%) coronary arteries. On a per-vessel basis, luminal stenosis severity was signifcantly associated with impaired FFR, iFR, resting Pd/Pa and iFRa. Multivariable analysis revealed that PR and LAP were independently related to an impaired FFR (p = 0.006 and p = 0.038, respectively) and iFRa (p = 0.005 and p = 0.027, respectively), next to stenosis severity (p <0.001 for all). Conversely, these adverse plaque characteristics were not related to the vasodilator free parameters iFR and Pd/Pa. Conclusion: CCTA derived vulnerable plaque characteristics are associated with detrimental hyperemic fow indices as assessed with FFR and iFRa, but not with non-hyperemic indices as defined by iFR and resting Pd/Pa. These findings suggest that induction of hyperemia is mandatory to reveal plaque vulnerability during hemodynamic interrogation of a coronary artery

Myocardial Blood Flow and Coronary Flow Reserve During 3 Years Following Bioresorbable Vascular Scaffold Versus Metallic Drug-Eluting Stent Implantation

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Coronary Collateral Flow Index Is Correlated with the Palmar Collateral Flow Index: Indicating Systemic Collateral Coherence in Individual Patients - Brief Report

Objective: The extent of the collateral circulation varies between individuals which affects morbidity and mortality. Experimental data show that collateral coherence between different organs is strain-dependent. Whether this interrelation is also present in humans is unknown. This study investigates the relation between the palmar and the coronary circulation in patients with coronary artery disease and which factors possibly influence collateral development. Approach and Results: In 50 patients with a chronic total occlusion, both the coronary collateral flow index (CFI) and the palmar CFI was measured. The correlation between both indices was determined, together with the relation to clinical variables. Mean coronary CFI was 0.51±0.16, and mean palmar CFI was 0.82±0.13. The coronary and palmar CFI were significantly correlated (ρ=0.48, P=0.001). Coronary CFI was 22% lower in low palmar CFI patients (<0.82) as compared with high palmar CFI patients (0.43±0.12 versus 0.57±0.18, P=0.03). In multivariable analysis, coronary CFI was significantly correlated with the palmar CFI and the duration of angina pectoris. Coronary CFI was inversely correlated with peripheral artery disease and systolic blood pressure. Conclusions: The coronary CFI and palmar CFI are significantly correlated, implicating collateral coherence between vascular beds in humans