185 Diagnostic accuracy of dynamic stress myocardial CT perfusion as compared with invasive coronary physiology metrics in stented patients: preliminary results of the advantage II study

Aims To compare the diagnostic performance of adenosine-stress dynamic myocardial perfusion assessed by CT (CTP) as compared with that of coronary CT angiography (CCTA) alone by using invasive fractional flow reserve (FFR) and index of microvascular resistance (IMR) as standard of reference. Diagnostic performance of CCTA for in-stent restenosis (ISR) detection is still challenging. Recently, CTP demonstrated additional specificity and diagnostic accuracy over CCTA alone in patients with previous stent implantation and suspected IRS or progression of coronary artery disease (CAD). However, no data are available in this clinical setting on the performance of CTP by using a new technique allowing for a non-invasive adjudication of regional myocardial blood flow (dynamic CTP) and to assess both macrovascular and microvascular disease status. Moreover, dynamic CTP was never compared vs. a comprehensive assessment of invasive coronary physiology (FFR and IMR). Methods and results We enrolled consecutive stable patients with previous coronary stenting referred for invasive coronary angiography (ICA) for clinical indication. All patients underwent dynamic stress myocardial CTP and rest CTP+CCTA by using a last generation scanner characterized by a 16-cm Z-axis coverage and fast (0.28 s) gantry rotation time. Invasive FFR and IMR were performed during ICA according to the standard practice. The diagnostic rate and diagnostic accuracy of CCTA and CTP were evaluated in a territory-based analyses vs. quantitative coronary angiography (QCA), FFR, and IMR. In 67 enrolled patients (55 men, mean age: 63.1 ± 8.2 years), the diagnostic rate (number of territories interpretable/number of territories evaluated) of CTP was significantly higher than that of CCTA (302/307 = 98.4% vs. 290/307 = 94.4%, P = 0.009). The interpretability of the combined CCTA/CTP approach was 99.7% (306/307 territories). When QCA was used as gold standard, CTP diagnostic accuracy was significantly higher than that of CCTA (84.4% vs. 80.1%, P = 0.01). When coronary physiology metrics were used as gold standard, CTP diagnostic accuracy was significantly higher than that of CCTA vs. both FFR (84.3% vs. 72.2%, P = 0.02) and IMR (83.3% vs. 70.2%, P = 0.02). The radiation exposure of CCTA+CTP was 8.7 ± 2.5 mSv. Conclusions In patients with coronary stents, dynamic CTP significantly improves diagnostic rate and accuracy of CCTA alone in comparison with both FFR and IMR. The non-invasive assessment of ISR is still challenging. The comprehensive assessment by cardiac CT provides anatomical combined to functional evaluation of coronary arteries in revascularized patients with good agreement with invasive physiological evaluation.

Bridging Coronary Physiology into Clinical Application of Acute Coronary Syndrome

Normal arteries have three layers of structure, tunica intima, tunica media, and tunica adventitia. Intima tunica is the deepest layer of coronary arteries in which there are antithrombotic molecules such as heparin sulfate, thrombomodulin, and plasminogen activator. In addition, tunica intima also contains substances that regulate the contraction of tunica smooth muscle cell media, called nitric oxide (vasodilators) and prostacyclin (vasoconstrictors). Tunica intima and tunica media seem to be directly related to the atherosclerosis process. Meanwhile, the role of tunika adventisia is unknown. The accumulation of atherosclerotic lesions and hemodynamic stress factors and the degradation of extracellular matrix will cause susceptibility of atherosclerotic plaque fibrous capsules to rupture and form thrombus. Thrombus that occurs in the coronary condition causes acute coronary syndrome, characterized by typical symptoms such as chest pain depending on the thrombus formed. In studying acute coronary syndromes, of course it cannot be separated from understanding the physiology of coronary arteries and the process of atherosclerosis. Therefore, this article aims to briefly explain coronary physiology.

Discordant resting and hyperaemic coronary physiology among unselected patients referred for coronary angiography: a single centre experience

Background Physiological assessment of intermediate coronary artery lesions to guide therapy is well established. Recently, the use of non-hyperaemic pressure ratios (NHPRs) has been suggested as a reliable alternative to hyperaemic assessment, such as fractional flow reserve (FFR). However certain patient / lesion subsets, including proximal lesion location, young patient age and assessment of non-LAD vessels, have been associated with discordance of resting and hyperaemic measurements which has led to some confusion over their interpretation and integration into routine clinical practice. Purpose To evaluate the frequency of discordant resting and hyperaemic measurements among patients undergoing assessment of intermediate coronary artery stenoses, and to identify common lesion-specific features within patients with discordant data. Methods From our coronary physiology database, we identified consecutive lesions which had been assessed between October 2020 and March 2021 with both resting (resting full-cycle ratio; RFR) and hyperaemic (wire-based FFR with peripheral adenosine) indices. Positive RFR defined as <0.89 (negative RFR >0.93, grey zone RFR 0.89–0.93). Positive FFR defined as <0.80 (negative FFR ≥0.80). Concordance between measurements was assessed: Group 1 (RFR -ve, FFR +ve: positive discordance); Group 2 (RFR -ve, FFR -ve: normal concordance), Group 3 (RFR +ve, FFR +ve: abnormal concordance) and Group 4 (RFR +ve, FFR -ve: negative discordance). Results 100 lesions were identified as being assessed with both RFR and FFR, in 83 patients (67% male), mean age 67 (±12) years, vessel assessed; LAD 66, RCA 19, LCx 13, LMCA 1 and radial graft 1; with 45 being proximal lesions. 30 RFR measurements were in the grey zone. Of the remaining 70 lesions, 55 results (79%) were concordant (Group 2 = 31, Group 3 = 24), with 15 results (21%) being discordant (Group 1 = 3, Group 4 = 12). Negative predictive value (NPV) of RFR (for FFR <0.80) was 91%, when grey zone RFR measurements were excluded. Discordance was not related to age (69 vs 68 years, p=0.75), lesion location (proximal lesion with discordance (6/15) vs proximal lesion with concordance (27/55), p=0.91, figure 1) or non-LAD vessel (non-LAD with discordance (9/15) vs non-LAD lesion with concordance (20/55), p=0.77, figure 2). Conclusion Overall within our patient group, there appeared to be a good association of RFR to FFR. In particular, RFR had a high NPV for an FFR <0.80. The clinical relevance of discordant measurements requires further investigation. However, our data suggest that a positive RFR (<0.89) measurement may not always correlate with a significant FFR measurement (<0.80), and the mechanism for this is unclear. Consequently, caution should be applied when including these measures in every day practice, in particular within patients with a positive RFR measurement. FUNDunding Acknowledgement Type of funding sources: None.

Relationship Between Immunoinflammation and Coronary Physiology Evaluated by Quantitative Flow Ratio in Patients With Coronary Artery Disease

Background: The association between coronary physiology and immunoinflammation has not been investigated. We performed a retrospective study using quantitative flow ratio (QFR) to evaluate the interaction between immunoinflammatory biomarkers and coronary physiology.Methods: A total of 172 patients with CAD who underwent coronary arteriography (CAG) and QFR were continuously enrolled from May 2020 to February 2021. As a quantitative indicator of coronary physiology, QFR can reflect the functional severity of coronary artery stenosis. The target vessel measured by QFR was defined as that with the most severe lesions. Significant coronary anatomical stenosis was defined as 70% stenosis in the target vessel.Results: Compared with the QFR > 0.8 group, interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ were increased and CD3+ and CD4+ T lymphocyte counts were decreased in the QFR ≤ 0.8 group. In addition, patients with DS ≤ 70% had higher IL-6, IL-10, and TNF-α levels and decreased CD3+ and CD4+ T lymphocyte counts than those with DS > 70%. Logistic regression analysis indicated IL-6 to be an independent predictor of significant coronary functional and anatomic stenosis (odds ratio, 1.125; 95% CI, 1.059–1.196; P < 0.001). Receiver operating characteristic (ROC) analyses showed that IL-6 > 6.36 was predictive of QFR ≤ 0.8 of the target vessel. The combination of IL-6, IL-10 and CD4 improved the value for predicting QFR ≤ 0.8 of the target vessel (AUC, 0.737; 95% CI, 0.661–0.810).Conclusion: Among immunoinflammatory biomarkers, IL-6 was independently associated with a higher risk of QFR ≤ 0.8 of the target vessel. The combination of immunoinflammatory biomarkers was highly predictive of significant coronary functional and anatomic stenosis.

The role of coronary physiology in contemporary percutaneous coronary interventions.

: Invasive assessment of coronary physiology has radically changed the paradigm of myocardial revascularization in patients with coronary artery disease. Despite the prognostic improvement associated with ischemia-driven revascularization strategy, functional assessment of angiographic intermediate epicardial stenosis remains largely underused in clinical practice. Multiple tools have been developed or are under development in order to reduce the invasiveness, cost, and extra procedural time associated with the invasive assessment of coronary physiology. Besides epicardial stenosis, a growing body of evidence highlights the role of coronary microcirculation in regulating coronary flow with consequent pathophysiological and clinical and prognostic implications. Adequate assessment of coronary microcirculation function and integrity has then become another component of the decision-making algorithm for optimal diagnosis and treatment of coronary syndromes. This review aims at providing a comprehensive description of tools and techniques currently available in the catheterization laboratory to obtain a thorough and complete functional assessment of the entire coronary tree (both for the epicardial and microvascular compartments).