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

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

Ischaemic burden and changes in absolute myocardial perfusion after chronic total occlusion percutaneous coronary intervention

AIMS: The aim of this study was to explore the relationships between ischaemic burden and changes in absolute myocardial perfusion following chronic coronary total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS AND RESULTS: A total of 193 consecutive patients underwent [15O]H2O positron emission tomography prior to and three months after successful CTO PCI. Change in perfusion defect size, quantitative hyperaemic myocardial blood flow (MBF) and coronary flow reserve (CFR) within the CTO area were compared among patients with limited (0-1 segment, N=15), moderate (2-3 segments, N=61) and large (≥4 segments, N=117) perfusion defects. Median reductions in defect size were 1 [0-1], 2 [1-3], and 4 [2-5] segments in patients with a limited, moderate and large defect (all comparisons p<0.01). Hyperaemic MBF and CFR improved significantly regardless of baseline defect size (overall between groups p=0.45 and p=0.55). After stratification of patients to a low, intermediate or high tertile according to baseline hyperaemic MBF or CFR levels, changes in hyperaemic MBF and CFR after CTO PCI were comparable between tertiles (overall p=0.75 and p=0.79). CONCLUSIONS: Major reductions in ischaemic burden can be achieved following CTO PCI, with more defect size reduction in patients with a larger perfusion defect, whereas hyperaemic MBF and CFR improve significantly irrespective of their baseline values or perfusion defect size. Visual summary. Major reductions in ischaemic burden can be achieved following CTO PCI. More defect size reduction in patients with a larger baseline perfusion defect. Significant hyperaemic MBF improvement irrespective of its baseline values

Impact of Specific Crossing Techniques in Chronic Total Occlusion Percutaneous Coronary Intervention on Recovery of Absolute Myocardial Perfusion

BACKGROUND: Multiple crossing techniques in chronic total occlusion (CTO) percutaneous coronary intervention have been developed. This study compared recovery of quantitative myocardial blood flow (MBF) after different CTO percutaneous coronary intervention techniques. METHODS: Consecutive patients with [15O]H2O positron emission tomography perfusion imaging before and 3 months after successful CTO percutaneous coronary intervention between 2013 and 2018 were included. Changes in hyperemic MBF, coronary flow reserve, and perfusion defect size were compared between antegrade wire escalation, retrograde wire escalation, antegrade dissection and reentry (ADR), and retrograde dissection and reentry. RESULTS: One hundred ninety-three patients were treated with antegrade wire escalation (N=90), retrograde wire escalation (N=24), ADR (N=35), and retrograde dissection and reentry (N=44). Increase in hyperemic MBF (1.19±0.77, 0.94±0.65, 1.09±0.63, and 1.02±0.75 mL·min-1·g-1, respectively; P=0.40) and coronary flow reserve (1.34±1.08, 1.14±1.09, 1.31±0.96, and 1.24±0.99, respectively; P=0.84) and decrease in defect size (3.2±2.1, 3.0±2.2, 2.7±2.1, and 2.9±1.9 segments, respectively; P=0.77) were comparable between the 4 approaches. In addition, recovery of hyperemic MBF was less pronounced after subintimal crossing with knuckle-wire-technique compared with CrossBoss in controlled ADR and retrograde dissection and reentry (0.93±0.69 versus 1.54±0.65 mL·min-1·g-1, P=0.02), and less after reentry using subintimal tracking and reentry in ADR compared with controlled ADR (Stingray) or limited antegrade subintimal tracking (0.60±0.53 versus 1.18±0.54 [P=0.04] and versus 1.49±0.57 mL·min-1·g-1, [P<0.01]). CONCLUSIONS: Recovery of hyperemic MBF, coronary flow reserve, and perfusion defect size after CTO percutaneous coronary intervention was comparable between different approaches. Although sometimes necessary to cross a complex CTO lesion, subintimal knuckle wiring and subintimal tracking and reentry resulted in less hyperemic MBF improvement compared with other subintimal crossing and reentry techniques