Coronary Hemodynamics Research Articles

Sex-differences in prevalence and outcomes of the different endotypes of chronic coronary syndrome – analysis from the multi-center international ILIAS Registry

Abstract Introduction Guideline-directed management of chronic coronary syndrome (CCS) remains focused on obstructive causes of angina, and is based on established therapies derived from studies predominantly including men. This occurs despite documented higher mortality from cardiovascular causes in women compared to men, which is hypothesized to be related to a higher prevalence of coronary microvascular dysfunction (CMD) in women. However, data on the relationship between sex, the different endotypes of CCS, and related sex-specific clinical outcomes are limited. Purpose This study aimed to investigate the relationship between sex and the different endotypes of CCS, as well as sex-specific clinical outcomes of CCS endotypes. Method In patients with stable angina undergoing coronary angiography, the following invasive coronary hemodynamics were characterized: fractional flow reserve (FFR; <0.80 considered abnormal), coronary flow reserve (CFR; <2.0 considered abnormal) and microcirculatory resistance (MR) (hyperemic microvascular resistance; >2.5mmHg/cm/sec or index of microvascular resistance >25 considered abnormal). Patients were stratified into three groups: 1) hemodynamically significant obstructive coronary artery disease (oCAD) (FFR abnormal or a severe coronary stenosis requiring revascularization), 2) no-obstructive coronary artery disease but with CMD (FFR normal, but abnormal CFR and/or MR), or 3) no-obstructive coronary artery disease and no CMD (FFR normal, and normal CFR and MR). We assessed the prevalence of the CCS endotypes across sex, and sex-specific cardiovascular outcomes over a follow-up of 7 years defined as the composite endpoint of death or acute myocardial infarction. Results Amongst a total of 1987 included patients, 1435 (72.2%) were men and 552 (27.8%) were women. oCAD occurred in 904 (45.5%) patients, which was significantly more prevalent in men (48.9% (701/1435) of men vs. 36.8% (203/552) of women, p<0.001). In contrast, CMD was significantly more prevalent in women (19.6% (281/1435) of men vs. 24.1% (133/552) of women, p=0.031). Across the population, either oCAD or CMD occurred in 68.4% of men versus 60.9% of women (p=0.002). There were no sex-specific differences in cardiovascular outcomes across CCS entities (Figure 1). Conclusion In patients evaluated for CCS who underwent clinically indicated coronary angiography and physiological assessment, men were more likely to have oCAD and women were more likely to be classified as CMD. There were no sex-related differences in the prognosis associated with the individual CCS endotypes. Therefore, pathophysiological changes in the coronary circulation potentially underlying angina pectoris are similarly prevalent in men and women, but the high incidence of CMD in women makes women prone to underdiagnosis if no additional physiological measurements are assessed. Funding Acknowledgement Type of funding sources: None.

CORONARY-SUBCLAVIAN STEAL SYNDROME, TREATED BY BALOON-EXPANDABLE PERIPHERAL STENT. CASE REPORT

Patient K., male smoker, 65 years old, suffering from type 2 diabetes, adhering to basic therapy, in year 2018 underwent isolated internal mammary bypass surgery for coronary artery disease. In 2022, due to a deterioration in general well-being in the form of stabbing pains behind the sternum, shortness of breath during physical exertion, pain and numbness of the left upper limb, he was scheduled for coronary angiography with shuntography. During routine shuntography through the left radial access, the presence of retrograde filling of the LIMA graft was established, indicating the presence of the phenomenon of coronary-subclavian steal. Elimination of hemodynamically significant stenosis of the left subclavian artery with a peripheral balloon-expandable stent led to successful remodeling of left coronary hemodynamics, relief of angina symptoms, and restoration of adequate blood flow in the left upper limb in the early postoperative period.

Morphometric Assessment for Functional Evaluation of Coronary Stenosis with Optical Coherence Tomography and the Optical Flow Ratio in a Vessel with Single Stenosis.

Objectives: The study aimed to evaluate the diagnostic performance of optical coherence tomography (OCT) in identifying functionally significant coronary stenosis in a vessel with single stenosis. Background: The OCT-based morphofunctional computational method for deriving the optical flow ratio (OFR) has diagnostic value, as it can identify the functional severity of coronary stenosis, but the ability of the OFR to aid the OCT in determining coronary stenosis hemodynamics in single-stenosis lesion remains unclear. Methods: 74 vessels with single stenosis were studied in 69 patients; all cases were performed through OCT and quantitative flow ratio (QFR), and OCT images were used to perform OFR. Results: Among vessels with single stenosis, OFR showed a good correlation with QFR (r = 0.86; p < 0.001). Taking QFR as the standard, the vessel-level diagnosis accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of OFR were 90% (95% CI: 81 to 96), 94% (95% CI: 77 to 99), 88% (95% CI: 74 to 96), 85% (95% CI: 68 to 94) and 95% (95% CI: 82 to 99), respectively. Among vessels with OFR/QFR concordance, both the minimum lumen area (MLA) and minimum lumen diameter (MLD) showed excellent diagnostic efficiency (MLA: area under the curve (AUC) = 0.92, 95% CI: 0.85 to 0.98, p < 0.001; MLD: AUC = 0.93, 95% CI: 0.86 to 0.98, p < 0.001) in determining the functional significance of coronary stenosis in a single stenosis lesion, and the best cutoff values were 1.55 mm2 and 1.40 mm. Conclusions: OFR has a good correlation with QFR. OCT-measured MLA and MLD have excellent diagnostic efficiency in identifying the hemodynamic significance of coronary stenosis in a vessel with single stenosis.

Сoronary paradox

This work is a scientific and educational analytical review intended for practicing cardiologists. The purpose of the review is to draw physicians’ attention to the role of myocardial contractility in the regulation of coronary circulation. We consider the fundamental phenomenon of arterial compression (squeezing) in the left ventricular (LV) wall, creating an obstruction to blood flow during cardiac systole. This phenomenon formally resembles functional coronary artery stenosis. Based on a review of the literature, the positive role of arterial compression in coronary hemodynamics is interpreted. Understanding the mechanical relationship between the contractile and coronary systems in the cardiac wall may be useful for practicing physicians when choosing treatment tactics for patients, optimizing LV bypass during heart surgeries, and improving the efficiency of adaptation of the transplanted heart.

Mechanical and hydrodynamic effects of stent expansion in tapered coronary vessels

Percutaneous coronary intervention (PCI) has become the primary treatment for patients with coronary heart disease because of its minimally invasive nature and high efficiency. Anatomical studies have shown that most coronary vessels gradually shrink, and the vessels gradually become thinner from the proximal to the distal end. In this paper, the effects of different stent expansion methods on the mechanical and hemodynamic behaviors of coronary vessels and stents were studied. To perform a structural-mechanical analysis of stent implantation, the coronary vessels with branching vessels and the coronary vessels with large bending curvature are selected. The two characteristic structures are implanted in equal diameter expansion mode and conical expansion mode, and the stress and mechanical behaviors of the coronary vessels and stents are analyzed. The results of the structural-mechanical analysis showed that the mechanical behaviors and fatigue performance of the cobalt-chromium alloy stent were good, and the different expansion modes of the stent had little effect on the fatigue performance of the stent. However, the equal diameter expansion mode increased distal coronary artery stress and the risk of vascular injury. The computational fluid dynamics analysis results showed that different stent expansion methods had varied effects on coronary vessel hemodynamics and that the wall shear stress distribution of conical stent expansion is more uniform compared with equal diameter expansion. Additionally, the vortex phenomenon is not apparent, the blood flow velocity is slightly increased, the hydrodynamic environment is more reasonable, and the risk of coronary artery injury is reduced.

Gradual Versus Abrupt Reperfusion During Primary Percutaneous Coronary Interventions in ST-Segment-Elevation Myocardial Infarction (GUARD).

BackgroundIntramyocardial edema and hemorrhage are key pathological mechanisms in the development of reperfusion‐related microvascular damage in ST‐segment–elevation myocardial infarction. These processes may be facilitated by abrupt restoration of intracoronary pressure and flow triggered by primary percutaneous coronary intervention. We investigated whether pressure‐controlled reperfusion via gradual reopening of the infarct‐related artery may limit microvascular injury in patients undergoing primary percutaneous coronary intervention.Methods and ResultsA total of 83 patients with ST‐segment–elevation myocardial infarction were assessed for eligibility and 53 who did not meet inclusion criteria were excluded. The remaining 30 patients with totally occluded infarct‐related artery were randomized to the pressure‐controlled reperfusion with delayed stenting (PCRDS) group (n=15) or standard primary percutaneous coronary intervention with immediate stenting (IS) group (n=15) (intention‐to‐treat population). Data from 5 patients in each arm were unsuitable to be included in the final analysis. Finally, 20 patients undergoing primary percutaneous coronary intervention who were randomly assigned to either IS (n=10) or PCRDS (n=10) were included. In the PCRDS arm, a 1.5‐mm balloon was used to achieve initial reperfusion with thrombolysis in myocardial infarction grade 3 flow and, subsequently, to control distal intracoronary pressure over a 30‐minute monitoring period (MP) until stenting was performed. In both study groups, continuous assessment of coronary hemodynamics with intracoronary pressure and Doppler flow velocity was performed, with a final measurement of zero flow pressure (primary end point of the study) at the end of a 60‐minute MP. There were no complications associated with IS or PCRDS. PCRDS effectively led to lower distal intracoronary pressures than IS over 30 minutes after reperfusion (71.2±9.37 mm Hg versus 90.13±12.09 mm Hg, P=0.001). Significant differences were noted between study arms in the microcirculatory response over MP. Microvascular perfusion progressively deteriorated in the IS group and at the end of MP, and hyperemic microvascular resistance was significantly higher in the IS arm as compared with the PCDRS arm (2.83±0.56 mm Hg.s.cm−1 versus 1.83±0.53 mm Hg.s.cm−1, P=0.001). The primary end point (zero flow pressure) was significantly lower in the PCRDS group than in the IS group (41.46±17.85 mm Hg versus 76.87±21.34 mm Hg, P=0.001). In the whole study group (n=20), reperfusion pressures measured at predefined stages in the early reperfusion period showed robust associations with zero flow pressure values measured at the end of the 1‐hour MP (immediately after reperfusion: r=0.782, P<0.001; at the 10th minute: r=0.796, P<0.001; and at the 20th minute: r=0.702, P=0.001) and peak creatine kinase MB level (immediately after reperfusion: r=0.653, P=0.002; at the 10th minute: r=0.597, P=0.007; and at the 20th minute: r=0.538, P=0.017). Enzymatic myocardial infarction size was lower in the PCRDS group than in the IS group with peak troponin T (5395±2991 ng/mL versus 8874±1927 ng/mL, P=0.006) and creatine kinase MB (163.6±93.4 IU/L versus 542.2±227.4 IU/L, P<0.001).ConclusionsIn patients with ST‐segment–elevation myocardial infarction, pressure‐controlled reperfusion of the culprit vessel by means of gradual reopening of the occluded infarct‐related artery (PCRDS) led to better‐preserved coronary microvascular integrity and smaller myocardial infarction size, without an increase in procedural complications, compared with IS.RegistrationURL: https://www.clinicaltrials.gov; Unique identifier: NCT02732080.

Modelling coronary flows: impact of differently measured inflow boundary conditions on vessel-specific computational hemodynamic profiles

Background and ObjectivesThe translation of hemodynamic quantities based on wall shear stress (WSS) or intravascular helical flow into clinical biomarkers of coronary atherosclerotic disease is still hampered by the assumptions/idealizations required by the computational fluid dynamics (CFD) simulations of the coronary hemodynamics. In the resulting budget of uncertainty, inflow boundary conditions (BCs) play a primary role. Accordingly, in this study we investigated the impact of the approach adopted for in vivo coronary artery blood flow rate assessment on personalized CFD simulations where blood flow rate is used as inflow BC. MethodsCFD simulations were carried out on coronary angiograms by applying personalized inflow BCs derived from four different techniques assessing in vivo surrogates of flow rate: continuous thermodilution, intravascular Doppler, frame count-based 3D contrast velocity, and diameter-based scaling law. The impact of inflow BCs on coronary hemodynamics was evaluated in terms of WSS- and helicity-based quantities. ResultsAs main findings, we report that: (i) coronary flow rate values may differ based on the applied flow derivation technique, as continuous thermodilution provided higher flow rate values than intravascular Doppler and diameter-based scaling law (p = 0.0014 and p = 0.0023, respectively); (ii) such intrasubject differences in flow rate values lead to different surface-averaged values of WSS magnitude and helical blood flow intensity (p<0.0020); (iii) luminal surface areas exposed to low WSS and helical flow topological features showed robustness to the flow rate values. ConclusionsAlthough the absence of a clinically applicable gold standard approach prevents a general recommendation for one coronary blood flow rate derivation technique, our findings indicate that the inflow BC may impact computational hemodynamic results, suggesting that a standardization would be desirable to provide comparable results among personalized CFD simulations of the coronary hemodynamics.

Effect of microcirculatory dysfunction on coronary hemodynamics: A pilot study based on computational fluid dynamics simulation

BackgroundInvasively measured fractional flow reserve (FFR) and index of microcirculatory resistance (IMR) are gold standards for the diagnosis of coronary artery disease (CAD) and coronary microcirculatory dysfunction (CMD). However, the interaction between CAD and CMD has not been comprehensively investigated. We aim to non-invasively investigate hemodynamic effect of CMD in nonobstructive CAD cases using computational fluid dynamics (CFD) simulation. MethodThis study employed CFD simulations on six cases with nonobstructive CAD and CMD in left anterior descending artery (LAD) territories. Two microcirculatory situations were simulated: normal microcirculatory resistance (MR) situation; CMD situation where MR at the outlets of LAD branches were multiplied by the ratio of clinically measured IMR to the cutoff value. Blood flow, translesional pressure drop (Δptl), and simulated FFR (FFRCT) of LAD and non-culprit branches were compared between the two microcirculatory situations using Wilcoxon signed rank test. ResultsThe results are in accordance with existing studies and clinical measurements. Compared with normal MR, there were significant decreases in outlet flow velocity and increases in FFRCT (p < 0.01 for both in Wilcoxon signed rank tests) in LAD branches with CMD, with minor decreases (0.63–5.64 mmHg) in Δptl. There was no significant influence on outlet flow velocity (< 2%) and FFRCT (< 0.02) in non-culprit branches (p > 0.05 for both). ConclusionIMR-based CFD simulation could estimate hemodynamic effects of CMD. CMD in a coronary artery branch can decrease its blood flow and Δptl, increase its FFR, with little effect on non-culprit branches.

Combined Assessment of FFR and CFR for Decision Making in Coronary Revascularization

The aim of this study was to demonstrate the clinical implications of combined assessment of fractional flow reserve (FFR) and coronary flow reserve (CFR).Combined assessment of FFR and CFR allows detailed characterization of pathophysiology in chronic coronary syndromes. Data on the clinical implications of distinct FFR and CFR patterns are limited, leading to uncertainty regarding their relevance.Patients with chronic coronary syndromes and obstructive coronary artery disease were selected from the multicenter ILIAS (Inclusive Invasive Physiological Assessment in Angina Syndromes) registry. Patients were classified into 4 groups on the basis of FFR ≤0.80 and CFR <2.0. The endpoint was the 5-year target vessel failure (TVF) rate.A total of 2,143 patients with 2,725 lesions were included. Compared with normal FFR/normal CFR, low FFR/low CFR carried the highest risk for TVF (HR: 5.4; 95% CI: 3.2-9.3; P < 0.001), significantly higher than in revascularized vessels (P = 0.007). Discordance, with either low FFR/normal CFR or normal FFR/low CFR, was associated with increased TVF rates compared with normal FFR/normal CFR (low FFR/normal CFR: HR: 3.5 [95% CI: 2.2-5.4; P < 0.001]; normal FFR/low CFR: HR: 3.0 [95% CI: 1.9-4.7; P < 0.001]). No difference in 5-year TVF was observed between the 2 discordant groups (P = 0.57) or between the discordant groups and the revascularized group (P = 0.26 vs low FFR/normal CFR; P = 0.60 vs normal FFR/low CFR).Impaired coronary hemodynamics are uniformly associated with increased 5-year TVF rates. Nonrevascularized vessels with discordant FFR and CFR are associated with 5-year event rates that are equivalent to those of vessels that undergo revascularization, whereas vessels with combined low FFR and CFR exhibit event rates that are significantly higher than after revascularization. (Inclusive Invasive Physiological Assessment in Angina Syndromes Registry [ILIAS Registry]; NCT04485234).

Early Post Heart Transplant Coronary Anatomic-Physiologic Characterization: ECAV Study

<h3>Purpose</h3> Cardiac allograft vasculopathy (CAV) is a leading cause of mortality and graft failure after heart transplantation. Early detection of CAV and accurate prognostication are essential for development of novel therapies and tailored patient management. The goal of this prospective study is to characterize anatomic-physiologic alterations in the coronary vasculature in the first year of heart transplantation to determine coronary phenotypes and predictors of early CAV. <h3>Methods</h3> Consecutive adult heart transplant (HT) recipients were enrolled from 2 Canadian institutions between January 2018-March 2021 (NCT03217786). Participants underwent comprehensive coronary evaluation at 3- and 12- months post HT with invasive coronary angiography (ICA), intravascular ultrasound (IVUS), optical coherence tomography and measurements of fractional flow reserve, coronary flow reserve and the index of microcirculatory resistance. Additional assessments included serum biomarker testing, microvasculopathy evaluation on endomyocardial biopsy and myocardial blood flow quantification by cardiac positron emission tomography. CAV was defined on ICA according to the ISHLT CAV_0-3 grading scale. Rapidly progressive CAV was defined on IVUS as ≥0.5 mm increase in maximal intimal thickness between baseline and 12-month follow-up studies. <h3>Endpoints</h3> We will present data from 86 HT patients (baseline demographics in Table), phenotyping early post transplant longitudinal changes in the coronary intima (intimal volume, percentage intimal volume, plaque characteristics), vessel remodeling and hemodynamics. Regression analysis will be performed to identify coronary anatomic-physiologic predictors of rapidly progressive CAV. This data will determine the role of early post transplant invasive coronary assessments for early CAV detection and identify high-risk patients who may benefit from early therapeutic intervention and intensive surveillance.

Challenges in Diagnosis and Functional Assessment of Coronary Artery Disease in Patients With Severe Aortic Stenosis.

More than half of patients with severe aortic stenosis (AS) over 70 years old have coronary artery disease (CAD). Exertional angina is often present in AS-patients, even in the absence of significant CAD, as a result of oxygen supply/demand mismatch and exercise-induced myocardial ischemia. Moreover, persistent myocardial ischemia leads to extensive myocardial fibrosis and subsequent coronary microvascular dysfunction (CMD) which is defined as reduced coronary vasodilatory capacity below ischemic threshold. Therefore, angina, as well as noninvasive stress tests, have a low specificity and positive predictive value (PPV) for the assessment of epicardial coronary stenosis severity in AS-patients. Moreover, in symptomatic patients with severe AS exercise testing is even contraindicated. Given the limitations of noninvasive stress tests, coronary angiography remains the standard examination for determining the presence and severity of CAD in AS-patients, although angiography alone has poor accuracy in the evaluation of its functional severity. To overcome this limitation, the well-established invasive indices for the assessment of coronary stenosis severity, such as fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), are now in focus, especially in the contemporary era with the rapid increment of transcatheter aortic valve replacement (TAVR) for the treatment of AS-patients. TAVR induces an immediate decrease in hyperemic microcirculatory resistance and a concomitant increase in hyperemic flow velocity, whereas resting coronary hemodynamics remain unaltered. These findings suggest that FFR may underestimate coronary stenosis severity in AS-patients, whereas iFR as the non-hyperemic index is independent of the AS severity. However, because resting coronary hemodynamics do not improve immediately after TAVR, the coronary vasodilatory capacity in AS-patients treated by TAVR remain impaired, and thus the iFR may overestimate coronary stenosis severity in these patients. The optimal method for evaluating myocardial ischemia in patients with AS and co-existing CAD has not yet been fully established, and this important issue is under further investigation. This review is focused on challenges, limitations, and future perspectives in the functional assessment of coronary stenosis severity in these patients, bearing in mind the complexity of coronary physiology in the presence of this valvular heart disease.

A Closed-Loop Modeling Framework for Cardiac-to-Coronary Coupling.

The mechanisms by which cardiac mechanics effect coronary perfusion (cardiac-to-coronary coupling) remain incompletely understood. Several coronary models have been proposed to deepen our understanding of coronary hemodynamics, but possibilities for in-depth studies on cardiac-to-coronary coupling are limited as mechanical properties like myocardial stress and strain are most often neglected. To overcome this limitation, a mathematical model of coronary mechanics and hemodynamics was implemented in the previously published multi-scale CircAdapt model of the closed-loop cardiovascular system. The coronary model consisted of a relatively simple one-dimensional network of the major conduit arteries and veins as well as a lumped parameter model with three transmural layers for the microcirculation. Intramyocardial pressure was assumed to arise from transmission of ventricular cavity pressure into the myocardial wall as well as myocardial stiffness, based on global pump mechanics and local myofiber mechanics. Model-predicted waveforms of global epicardial flow velocity, as well as of intramyocardial flow and diameter were qualitatively and quantitatively compared with reported data. Versatility of the model was demonstrated in a case study of aortic valve stenosis. The reference simulation correctly described the phasic pattern of coronary flow velocity, arterial flow impediment, and intramyocardial differences in coronary flow and diameter. Predicted retrograde flow during early systole in aortic valve stenosis was in agreement with measurements obtained in patients. In conclusion, we presented a powerful multi-scale modeling framework that enables realistic simulation of coronary mechanics and hemodynamics. This modeling framework can be used as a research platform for in-depth studies of cardiac-to-coronary coupling, enabling study of the effect of abnormal myocardial tissue properties on coronary hemodynamics.

Thirty Years of No-Touch Saphenous Vein Harvesting: A Timely Jubilee Gift

Thirty Years of No-Touch Saphenous Vein Harvesting: A Timely Jubilee Gift

Association of Plaque Location and Vessel Geometry Determined by Coronary Computed Tomographic Angiography With Future Acute Coronary Syndrome–Causing Culprit Lesions

Distinct plaque locations and vessel geometric features predispose to altered coronary flow hemodynamics. The association between these lesion-level characteristics assessed by coronary computed tomographic angiography (CCTA) and risk of future acute coronary syndrome (ACS) is unknown. To examine whether CCTA-derived adverse geometric characteristics (AGCs) of coronary lesions describing location and vessel geometry add to plaque morphology and burden for identifying culprit lesion precursors associated with future ACS. This substudy of ICONIC (Incident Coronary Syndromes Identified by Computed Tomography), a multicenter nested case-control cohort study, included patients with ACS and a culprit lesion precursor identified on baseline CCTA (n = 116) and propensity score-matched non-ACS controls (n = 116). Data were collected from July 20, 2012, to April 30, 2017, and analyzed from October 1, 2020, to October 31, 2021. Coronary lesions were evaluated for the following 3 AGCs: (1) distance from the coronary ostium to lesion; (2) location at vessel bifurcations; and (3) vessel tortuosity, defined as the presence of 1 bend of greater than 90° or 3 curves of 45° to 90° using a 3-point angle within the lesion. Association between lesion-level AGCs and risk of future ACS-causing culprit lesions. Of 548 lesions, 116 culprit lesion precursors were identified in 116 patients (80 [69.0%] men; mean [SD], age 62.7 [11.5] years). Compared with nonculprit lesions, culprit lesion precursors had a shorter distance from the ostium (median, 35.1 [IQR, 23.6-48.4] mm vs 44.5 [IQR, 28.2-70.8] mm), more frequently localized to bifurcations (85 [73.3%] vs 168 [38.9%]), and had more tortuous vessel segments (5 [4.3%] vs 6 [1.4%]; all P < .05). In multivariable Cox regression analysis, an increasing number of AGCs was associated with a greater risk of future culprit lesions (hazard ratio [HR] for 1 AGC, 2.90 [95% CI, 1.38-6.08]; P = .005; HR for ≥2 AGCs, 6.84 [95% CI, 3.33-14.04]; P < .001). Adverse geometric characteristics provided incremental discriminatory value for culprit lesion precursors when added to a model containing stenosis severity, adverse morphological plaque characteristics, and quantitative plaque characteristics (area under the curve, 0.766 [95% CI, 0.718-0.814] vs 0.733 [95% CI, 0.685-0.782]). In per-patient comparison, patients with ACS had a higher frequency of lesions with adverse plaque characteristics, AGCs, or both compared with control patients (≥2 adverse plaque characteristics, 70 [60.3%] vs 50 [43.1%]; ≥2 AGCs, 92 [79.3%] vs 60 [51.7%]; ≥2 of both, 37 [31.9%] vs 20 [17.2%]; all P < .05). These findings support the concept that CCTA-derived AGCs capturing lesion location and vessel geometry are associated with risk of future ACS-causing culprit lesions. Adverse geometric characteristics may provide additive prognostic information beyond plaque assessment in CCTA.

Open chest selective aortic arch perfusion vs open cardiac massage as a means of perfusion during in exsanguination cardiac arrest: a comparison of coronary hemodynamics in swine.

To describe and compare the aortic-right atrial pressure (AoP-RAP) gradients and mean coronary perfusion pressures (CPPs) generated during open chest selective aortic arch perfusion (OCSAAP) with those generated during open cardiac massage (OCM) in hypovolemic swine. Ten male Hanford swine utilized in a prior poly-trauma study were included in the study. Animals were rendered hypovolemic via a 30% volume bleed. Upon confirmation of death, animals underwent immediate clamshell thoracotomy and aortic cross-clamping followed by 5min of OCM. A catheter suitable for OCSAAP was then inserted into the aorta and animals underwent 1min of OCSAAP at a rate of 10mL/kg/min. Aortic and right atrial pressures were recorded continuously using solid-state blood pressure catheters. Representative 10-s intervals from each resuscitation method were extracted. Hemodynamic parameters including AoP-RAP gradients and CPPs were calculated and compared. At baseline, time from death to intervention was significantly shorter for OCM. However, mean CPPs and AoP-RAP gradients were significantly higher in animals undergoing OCSAAP. 98% of OCSAAP segments had a mean CPP > 15, compared to 35% of OCM intervals. While OCM had a significant negative correlation between time to intervention and maximum CPP, this correlation was not significant for OCSAAP. OCSAAP generates favorable and potentially time-resistant pressure gradients when compared to those generated by OCM. Further investigation of the technique of OCSAAP is warranted, as it may have potential utility as a therapy during resuscitative thoracotomy (RT).

Validation of Non-Invasive Endothelial Shear Stress (ESS) Estimations of Coronary Artery Haemodynamics via In-Silico and In-Vivo Modelling

Endothelial shear stress (ESS) is parallel frictional force exerted by blood flow on the coronary luminal surface and is associated with the development and progression of atherosclerosis. Computational fluid dynamics (CFD) is an engineering method used to analyse fluid flow and has been increasingly applied to simulate ESS. However, current CFD-ESS estimates have never been validated and can display significant variability between research groups. This study aims to provide a comparative analysis of coronary flow using in-silico modelling of coronary flow and particle image velocimetry (PIV). A proximal left anterior descending (pLAD) coronary phantom model was constructed from a patient who had received same day cardiac computed tomography angiography (CTCA) and invasive coronary haemodynamic (Combowire XT) assessment. Patient-specific coronary flow data was applied to CFD boundary conditions and a mock circulatory loop. CFD via PIV under steady flow in a 4-times-scaled model was validated. Same plane velocity field and flow patterns (at mid-luminal of pLAD) from both in-silico and in-vivo data were compared. Mean velocity contours and magnitude were analysed from CFD and PIV. Patient specific average peak velocity obtained from invasive assessment was 0.21m/s. Patient-specific velocity average from CFD was 0.22m/s. The approximated magnitude difference is 4.7%. Velocity contours and flow patterns simulated in the CFD were also comparable with the PIV results. Simulation data from CFD correlate well with experimental PIV results. This early data allows for a non-invasive approach to determine patient-specific coronary haemodynamics (such as velocity profiling and ESS).

Non Invasive Detection of Coronary Sinus Flow Changes Over Time After CABG.

Background:Coronary New blood in the vascular bed after Coronary Artery Bypass Grafting (CABG) may represent a turning point between ischemia and normal tissue nutrition. Its quantification can help to better understand coronary artery hemodynamics after revascularization.Objective:Quantification of coronary sinus blood flow changes over time after Coronary Artery Bypass Grafting (CABG) using Transthoracic Echocardiography (TTE).Methods:Prospective basic research, with repeated measurements on hospital sample of 61 patients whom CABG was conducted. We performed TTE recordings to measure CS flow before and two times after CABG (1 and 6 postoperative day). We measure CS diameter, Velocity Time Integral (VTI) and systemic hemodynamic data. Data needed for LV mass calculation were recorded once. During statistical analysis we define: α = 0,01, β = 0,01 (power = 1-β β= 0,99), Sample size = 60, Effect size= 0,68. We used ANOVA for Repeated Measures as main statistical test in SPSS.Results:Preoperatively we found low overall CS flow of 181 ±72 ml/min (0,68 ±0,30 ml/gram-LV/min). After surgery there was constant increase of CS flow from 276 ±79 ml/min (1,13 ±0,35 ml/gram-LV/min) first postoperative day, to 355 (±99) ml/min (1,30 ±0,46 ml/gram-LV/min) sixth postoperative day.Discussion:Amount of new blood was statistically significant after CABG with P<0,001. Same result was found after classifying patients per number of graft received, with the highest amount of new blood after four bypasses. Amount of new blood was not different if patient gets two or three bypasses.Conclusion:There was significantly new amount of blood in coronary bed after CABG, with constant increase over first 6 days.

Non-invasive Ischaemia Testing in Patients With Prior Coronary Artery Bypass Graft Surgery: Technical Challenges, Limitations, and Future Directions.

Coronary artery bypass graft (CABG) surgery effectively relieves symptoms and improves outcomes. However, patients undergoing CABG surgery typically have advanced coronary atherosclerotic disease and remain at high risk for symptom recurrence and adverse events. Functional non-invasive testing for ischaemia is commonly used as a gatekeeper for invasive coronary and graft angiography, and for guiding subsequent revascularisation decisions. However, performing and interpreting non-invasive ischaemia testing in patients post CABG is challenging, irrespective of the imaging modality used. Multiple factors including advanced multi-vessel native vessel disease, variability in coronary hemodynamics post-surgery, differences in graft lengths and vasomotor properties, and complex myocardial scar morphology are only some of the pathophysiological mechanisms that complicate ischaemia evaluation in this patient population. Systematic assessment of the impact of these challenges in relation to each imaging modality may help optimize diagnostic test selection by incorporating clinical information and individual patient characteristics. At the same time, recent technological advances in cardiac imaging including improvements in image quality, wider availability of quantitative techniques for measuring myocardial blood flow and the introduction of artificial intelligence-based approaches for image analysis offer the opportunity to re-evaluate the value of ischaemia testing, providing new insights into the pathophysiological processes that determine outcomes in this patient population.

Baseline neuroimaging characteristics in the randomized pivotal study of renew NCP‐5 for the treatment of mild cognitive impairment (MCI) due to Alzheimer's disease or mild dementia of the Alzheimer's type

AbstractBackgroundRenew NCP‐5 is an FDA‐cleared, external counterpulsation (ECP) device used clinically to improve coronary and peripheral vascular hemodynamics by sequential compression and decompression of vascular beds in synchrony with the cardiac cycle. NCP‐5 treatment may have a beneficial effect on disorders of blood flow including mild cognitive impairment (MCI) and Alzheimer’s disease (AD). We describe here the baseline neuroimaging characteristics of the participants from a randomized pivotal study of Renew NCP‐5 for the treatment of MCI due to AD or mild dementia of the Alzheimer's type.MethodNeuroimaging was conducted across ten sites in the United States for safety screening, baseline imaging assessment including disease severity, and for acquisition of exploratory neuroimaging markers of treatment modification. Imaging protocols were based on the cross‐platform protocols developed for the Alzheimer's Disease Neuroimaging Initiative (ADNI3). Participant characterization and exploratory outcome neuroimaging measures included T1‐weighted hippocampal volume and arterial spin labeling‐based measures of cerebral blood flow (CBF).ResultBaseline structural data were acquired in 97 participants in the NCP‐5 group, and 89 participants in the active sham group. ASL data were available on a subset of scanners and acquired in 60 participants in the NCP‐5 group and 48 participants in the active sham group. Baseline neuroimaging assessment revealed expected variation with age and disease severity in the total cohort. A difference in baseline hippocampal volume and CBF was detected between the randomized groups with the NCP‐5 group having reduced measures (reduced hippocampal volume and reduced CBF) compared to the active sham group. These effects were apparent when splitting the treatment groups by disease severity and cardiovascular risk.ConclusionWe present here the baseline characteristics for the participant cohort for the randomized pivotal study of Renew NCP‐5 for the treatment of MCI due to AD or mild dementia of the Alzheimer's type. Imaging measures were in accord with expected directional effects for age and for disease. There was an unexpected difference between the NCP‐5 treatment and active sham group at baseline with the NCP‐5 group having greater neurodegeneration. Longitudinal imaging data are being examined in ongoing work.

RESPONSE: Coronary Anatomy, Hemodynamics, and Racism: The New Cardiology Training Curriculum?

RESPONSE: Coronary Anatomy, Hemodynamics, and Racism: The New Cardiology Training Curriculum?