Comparison of fractional myocardial mass, a vessel-specific myocardial mass-at-risk, with coronary angiographic scoring systems for predicting myocardial ischemia.

AIMS: The burden of coronary artery disease has been assessed by various semi-quantitative angiographic scores, which are frequently different each other. A non-invasive and quantitative modality may substitute angiographic sores for prognostic implication and decision of revascularization strategy. We compared fractional myocardial mass (FMM) with angiographic scores for predicting myocardial ischemia. METHODS: In this multicenter registry, 411 patients who underwent coronary computed tomography angiography (CCTA) were followed by invasive coronary angiography and fractional flow reserve (FFR) measurement. CCTA-derived %FMM with diameter stenosis≥70% (%FMM-70) or ≥50% (%FMM-50) were compared with 9 angiographic scores (APPROACH, Duke Jeopardy, BARI, CASS, SYNTAX, Jenkins, BCIS-1, Leaman, Modified Duke) and were tested regarding their performance for predicting FFR≤0.80. RESULTS: The performance of %FMM-70 and %FMM-50 were similar to most angiographic scores (%FMM-70, c-statistics = 0.74; %FMM-50, 0.73; angiographic scores, 0.68-0.77). The frequency of FFR≤0.80 increased consistently according to %FMM-70, %FMM-50, and all angiographic scores (p < 0.001, all). The optimal cutoff of %FMM-50 and %FMM-70 for FFR≤0.80 were ≥36.3% and ≥8.7%, respectively. Using these cutoffs, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of %FMM-50 were 81%, 55%, 3%, 67%, 71%, and of %FMM-70 were 67%, 78%, 82%, 61%, 71%. CONCLUSION: %FMM was comparable to angiographic scores for prediction of functional stenosis defined by FFR≤0.80. The integration of the severity of stenosis and the amount of subtended myocardium may improve the detection of the functional significance of vessel.

Prognostic implications of post-percutaneous coronary intervention neutrophil-to-lymphocyte ratio on infarct size and clinical outcomes in patients with acute myocardial infarction.

This study evaluated the prognostic implications of post-percutaneous coronary intervention (PCI) neutrophil-to-lymphocyte ratio (NLR) in patients with acute myocardial infarction (AMI). A total of 309 patients with AMI who underwent cardiac magnetic resonance imaging (CMR) and a complete blood cell count within 24 hours before and after PCI were enrolled. Primary outcome was infarct size. Patients were assigned to high (n = 118) or low (n = 191) NLR groups according to the best cut-off value of 3.88. Infarct size (% of total left ventricular mass) was significantly higher in the high NLR group than in the low NLR group (24.1 ± 11.0 vs. 16.7 ± 9.1, p < 0.001). Post-PCI NLR ≥ 3.88 was associated with risk of a large-sized infarction (≥20%) (OR 2.91, 95% CI 1.73-4.88, p < 0.001). The risk of MACE was also significantly higher in the high NLR group than in the low NLR group (15.8% vs. 7.4%, HR 2.60, 95% CI 1.21-5.60, p = 0.015). Among patients with AMI who underwent PCI, high post-PCI NLR value was associated with higher risk of large-sized infarction as measured by CMR, as well as adverse clinical outcomes. Our findings suggest that post-PCI NLR is a useful tool for risk assessment in patients with AMI who undergo PCI.

Computationally simulated fractional flow reserve from coronary computed tomography angiography based on fractional myocardial mass.

Computed tomography angiography (CCTA)-based calculations of fractional flow reserve (FFR) can improve the diagnostic performance of CCTA for physiologically significant stenosis but the computational resource requirements are high. This study aimed at establishing a simple and efficient algorithm for computing simulated FFR (S-FFR). A total of 107 patients who underwent CCTA and invasive FFR measurements were enrolled in the study. S-FFR was calculated using 145 evaluable coronary arteries with off-the-shelf softwares. FFR ≤ 0.80 was a reference threshold for diagnostic performance of diameter stenosis (DS) ≥ 50%, DS ≥ 70%, or S-FFR ≤ 0.80. FFR ≤ 0.80 was identified in 78 vessels (54%). In per-vessel analysis, S-FFR showed good correlation (r = 0.83) and agreement (mean difference = 0.02 ± 0.08) with FFR. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of S-FFR ≤ 0.80 for FFR ≤ 0.80 were 84%, 92%, 92%, 83%, and 88%, respectively. S-FFR ≤ 0.80 showed much higher predictive performance for FFR ≤ 0.80 compared with DS ≥ 50% or DS ≥ 70% (c-statistics = 0.92 vs. 0.58 or 0.65, p < 0.001, all). The classification agreement between FFR and S-FFR was > 80% when the average of FFR and S-FFR was < 0.76 or > 0.86. Per-patient analysis showed consistent results. In this study, a simple and computationally efficient simulated FFR (S-FFR) algorithm is designed and tested using non-proprietary off-the-shelf software. This algorithm may expand the accessibility of clinical applications for non-invasive coronary physiology study.

Identification of Coronary Artery Side Branch Supplying Myocardial Mass That May Benefit From Revascularization.

OBJECTIVES: The authors sought to identify whether a coronary side branch (SB) is supplying a myocardial mass that may benefit from revascularization. BACKGROUND: The amount of subtending myocardium and physiological stenosis is frequently different between the main vessel (MV) and SB. METHODS: In this multicenter registry, 482 patients who underwent coronary computed tomography angiography and fractional flow reserve (FFR) measurement were enrolled. The % fractional myocardial mass (FMM), the ratio of vessel-specific myocardial mass to whole myocardium, was assessed in 5,860 MV or SB consisting of 2,930 bifurcations. Physiological stenosis was defined by fractional flow reserve (FFR) <0.80. Myocardial mass that may benefit from revascularization was defined by %FMM ≥10%. RESULTS: In per-bifurcation analysis, MV supplied a 1.5- to 9-fold larger myocardial mass compared with SB. Unlike left main bifurcation (n = 482), only 1 of every 5 non-left main SB (n = 2,448) supplied %FMM ≥10% (97% vs. 21%; p < 0.001). SB length ≥73 mm could estimate %FMM ≥10% (c-statistic = 0.85; p < 0.001). In 604 vessels interrogated by FFR, diameter stenosis was similar (p = NS), but %FMM ≥10%, FMM/minimal luminal diameter, and frequency of FFR <0.80 was higher in MV compared with SB (p < 0.001, all). Generalized estimating equations modeling demonstrate that vessel diameter, left myocardial mass, and FFR were not (p = NS), but SB length ≥73 mm and left main bifurcation were significant predictors for %FMM ≥10% (p < 0.001). CONCLUSIONS: Compared with MV, SB supplies a smaller myocardial mass and showed less physiological severity despite similar stenosis severity. SB supplying a myocardial mass of %FMM≥10%, which may benefit revascularization could be identified by vessel length ≥73 mm. Pre-procedural recognition of these findings may guide optimal revascularization strategy for bifurcation.

Physiological Severity of Coronary Artery Stenosis Depends on the Amount of Myocardial Mass Subtended by the Coronary Artery.

OBJECTIVES: This study investigated the role of fractional myocardial mass (FMM), a vessel-specific myocardial mass, in the evaluation of physiological severity of stenosis. Using computed tomography angiography, the study investigated fractional myocardial mass, a concept of myocardial mass subtended by specific vessel, which could reduce anatomical-physiological mismatch. BACKGROUND: Discordance between anatomical stenosis and physiological severity is common but remains poorly understood. METHODS: This multicenter study enrolled 463 patients with 724 lesions, who underwent coronary computed tomography angiography (CCTA) and invasive coronary angiography with fractional flow reserve (FFR) measurement. FMM was assessed by allometric scaling analysis of arterial tree length and myocardial mass from CCTA. RESULTS: FFR <0.80, a criteria for vessel-specific physiological stenosis, was found in 281 vessels (39%). FMM decreased consistently according to the vessel downstream (p < 0.001, all). The frequency of FFR <0.80 increased in proportion to FMM and inverse proportion to angiographic minimal luminal diameter (MLD) (p < 0.001). In per-vessel analysis, FMM per MLD (FMM/MLD) showed good correlation with FFR (r = 0.61) and was superior to diameter stenosis (DS) for FFR <0.80 by receiver operating characteristic and reclassification analysis (C-statistics = 0.84 versus 0.74, net reclassification improvement [NRI] = 0.63, integrated discrimination improvement [IDI] = 0.18; p < 0.001, all). The optimal cutoff of FMM/MLD was 29 g/mm, with sensitivity = 75%, specificity = 77%, positive predictive value = 68%, negative predictive value = 83%, and accuracy = 77%. Addition of FMM/MLD to DS could further discriminate vessels with FFR <0.80 (C-statistic = 0.86 vs. 0.84, NRI = 0.34, IDI = 0.03; p < 0.005, all). In per-range classification analysis, agreement between FFR and FMM/MLD maintained >80% when the severity of disease was away from cutoff. CONCLUSIONS: FMM/MLD could find physiological severity of coronary artery with higher accuracy than anatomical stenosis. FMM may explain the anatomical-physiological discordance.

Early detection of subclinical ventricular deterioration in aortic stenosis with cardiovascular magnetic resonance and echocardiography.

BACKGROUND: Severe aortic stenosis (AS) patients with late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) or left ventricular (LV) systolic dysfunction are known to have worse outcome. We aimed to investigate whether LGE on CMR would be useful in early detection of subclinical LV structural and functional derangements in AS patients. METHODS: 118 patients with moderate to severe AS were prospectively enrolled. Echocardiography and CMR images were taken and the patients were divided into groups according to the presence/absence of LGE and of LV systolic dysfunction (LV ejection fraction (EF) <50%). The stiffness of LV was calculated based on Doppler and CMR measurements. RESULTS: Patients were grouped into either group 1, no LGE and normal LVEF, group 2, LGE but normal LVEF and group 3, LGE with depressed LVEF. There was a significant trend towards increasing LV volumes, worsening of LV diastolic function (E/e', diastolic elastance), systolic function (end-systolic elastance) and LV hypertrophy between the three groups, which coincided with worsening functional capacity (all p-value < 0.001 for trend). Also, significant differences in the above parameters were noted between group 1 and 2 (E/e', 14.6 ± 4.3 (mean ± standard deviation) in group 1 vs. 18.2 ± 9.4 in group 2; end-systolic elastance, 3.24 ± 2.31 in group 1 vs. 2.38 ± 1.16 in group 2, all p-value < 0.05). The amount of myocardial fibrosis on CMR correlated with parameters of diastolic (diastolic elastance, Spearman's ρ = 0.256, p-value = 0.005) and systolic function (end-systolic elastance, Spearman's ρ = -0.359, p-value < 0.001). CONCLUSIONS: These findings demonstrate the usefulness of CMR for early detection of subclinical LV structural and functional deterioration in AS patients.

Frequency of myocardial infarction and its relationship to angiographic collateral flow in territories supplied by chronically occluded coronary arteries.

BACKGROUND: Despite complete interruption of antegrade coronary artery flow in the setting of a chronic total occlusion (CTO), clinical recognition of myocardial infarction is often challenging. Using cardiac MRI, we investigated the frequency and extent of myocardial infarction in patients with CTO, and assessed their relationship with regional systolic function and the extent of angiographic collateral flow. METHODS AND RESULTS: We included 170 consecutive patients (median age, 62 years) with angiographically documented CTO. Regional late gadolinium enhancement and wall motion score index were assessed by cardiac MRI with the use of a 17-segment model. Angiographic collateral flow was assessed by the collateral connection grade and the Rentrop score. Evidence of previous myocardial infarction was found in 25% of patients by ECG Q waves, in 69% by regional wall motion abnormality, and in 86% of patients by late gadolinium enhancement. Increased angiographic collateral flow was associated with a lower frequency of Q waves on ECG, and a lower regional wall motion score index, late gadolinium enhancement volume (%), and degree of late gadolinium enhancement transmurality (all P<0.001), as well. CONCLUSIONS: The frequency of myocardial infarction in territories subtended by CTO is significantly higher than previously recognized. The degree of myocardial injury downstream epicardial CTO is inversely correlated with the degree of angiographic collaterals.

Three-dimensional quantitative volumetry of chronic total occlusion plaque using coronary multidetector computed tomography.

BACKGROUND: The purpose of the present study was to investigate whether multidetector computed tomography (MDCT) can identify the nature of chronic total occlusion (CTO) plaque, which cannot be measured quantitatively using traditional coronary angiography, and predict the success of percutaneous coronary intervention (PCI). METHODS AND RESULTS: MDCT and 3-dimensional volumetric radiologic density analysis was performed for 186 consecutive CTO lesions. Plaque characteristics were determined using Hounsfield units (HU) of the image voxels. The remodeling index decreased significantly as the duration of CTO lengthened. Volumetric plaque analysis using HU showed that volumetric fraction of calcification (>324HU) did not, but low-density plaque (<49HU) did decrease significantly as the duration of CTO lengthened. The overall PCI success rate was 77.4% (144/186). In addition to the unknown or >12-month occlusion duration (odds ratio [OR]=3.0, 95% confidence interval [CI]=1.4-6.5, P=0.005), 2 MDCT parameters, that is, lesion length >18mm (OR=2.7, 95%CI=1.1-6.4, P=0.024) and segmental radiologic density >139HU (OR=2.7, 95%CI=1.2-6.4, P=0.021), were independent predictors of PCI failure on multivariate analysis. CONCLUSIONS: MDCT might be helpful for the prediction of successful CTO PCI. In addition to the occlusion duration, lesion length and high segmental radiologic density measured on MDCT were significant predictors of PCI failure in the present study.

Comparison of the coronary calcium score with the estimated coronary risk.

OBJECTIVES: The role of coronary calcium scoring in coronary risk estimation is not well established. Calcium scoring could provide additional information in a certain subgroup of patients where the calcium score does not match the conventional Framingham risk estimates. We explored the characteristics of such a subgroup. METHODS: The study participants were 1653 asymptomatic persons who underwent routine health screening and calcium scoring using the 16-slice multidetector computed tomography. Risk stratification was performed in five categories both by 10-year Framingham coronary risk and the Agatston coronary calcium score. RESULTS: Risk stratifications by coronary calcium score and absolute risk showed a large discrepancy (difference > or =3 classes) in about 9% of participants. The proportion increased with age (P for trend <0.0001). An exploratory analysis revealed that age (partial R=0.109, P<0.0001) and the presence of the metabolic syndrome (partial R=0.025, P<0.001) were independent variables that accounted for the variance of the residual of regression between the log-transformed value of coronary calcium score and the absolute risk. CONCLUSION: Calcium scoring may be clinically more useful in older (> or =50 years) participants and/or in participants with the metabolic syndrome because of the relatively higher probability of obtaining additional information that the conventional Framingham risk estimation cannot provide.