Additional prognostic impact of plaque characterization with on-site CT-derived fractional flow reserve in coronary CT angiography.

BACKGROUND: On-site computed tomography-derived fractional flow reserve (CT-FFR) is a feasible method for examining lesion-specific ischemia, and plaque analysis of coronary CT angiography (CCTA) is useful for predicting future cardiac events. However, their utility and association on a per-vessel level remain unclear. METHODS: We analyzed vessels showing 50-90 % stenosis on CCTA where planned revascularization was not performed after CCTA within 90 days. Relevant features, including CT-FFR and the plaque burden [necrotic core to the total plaque volume (% necrotic core), and non-calcified plaque (NCP) to vessel volume (% NCP)] using a novel algorithm for analyzing plaque to predict vessel-oriented composite outcomes (VOCO), including cardiac death, non-fatal myocardial infarction, and unplanned vessel-related revascularization, were assessed. RESULTS: In 256 patients (68.7 ±â€¯9.4 years; 73.8 % male) with 354 vessels (10.5 % CT-FFR ≤ 0.80), VOCO occurred in 24 vessels (6.8 %) during a median follow-up of 3.6 years. Multivariable Cox analysis revealed CT-FFR ≤ 0.80 had the pronounced impact on VOCO, and moreover, higher % necrotic core and % NCP were independently associated with VOCO [adjusted hazard ratio 3.43 (95 % confidence interval 1.42-8.29) and 4.05 (1.19-13.71), respectively], especially for vessels with CT-FFR > 0.80. CONCLUSIONS: In vessels without planned revascularization, per-vessel CT-FFR ≤ 0.80 was the notable predictor of future cardiac events. Additionally, necrotic core volume and NCP were identified as independent predictors along with CT-FFR.

Outcome after primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction complicated by cardiogenic shock.

BACKGROUND: Primary percutaneous coronary intervention (PCI) for ST-segment-elevation myocardial infarction (STEMI) complicated by cardiogenic shock (CS) may reduce the risk of subsequent cardiovascular events but remains challenging. The study aim was to evaluate the clinical characteristics and long-term outcomes of patients undergoing primary PCI for STEMI with CS. METHODS: We conducted an observational cohort study of patients with STEMI who underwent primary PCI between April 2004 and December 2017 at Juntendo University Shizuoka Hospital. The primary outcome was cardiovascular death (CVD) during the median 3-year follow-up. We performed a landmark analysis for the incidence of CVD from 0 day to 1 year and from 1 to 10 years. RESULTS: Among the 1758 STEMI patients in the cohort, 212 (12.1 %) patients with CS showed significantly higher 30-day CVD rate on admission than those without (26.4 % vs 2.9 %). Landmark Kaplan-Meier analysis showed that CVD from day 0 to year 1 was significantly higher in the patients with CS (log-rank p < 0.0001). Multivariate Cox regression analysis showed that CS was significantly associated with higher cardiovascular mortality (adjusted hazard ratio, 11.8; 95%confidence intervals, 7.78-18.1; p < 0.0001), but the mortality rates from 1 to 10 years were comparable (log-rank p = 0.68). CONCLUSION: The cardiovascular 1-year mortality rate for patients with STEMI was higher for those with CS on admission than without, but the mortality rates of >1 year were comparable. Surviving the early phase is essential for patients with STEMI and CS to improve long-term outcomes.

Fully automated coronary artery calcium quantification on electrocardiogram-gated non-contrast cardiac computed tomography using deep-learning with novel Heart-labelling method.

Aims: To develop an artificial intelligence (AI)-model which enables fully automated accurate quantification of coronary artery calcium (CAC), using deep learning (DL) on electrocardiogram (ECG)-gated non-contrast cardiac computed tomography (gated CCT) images. Methods and results: Retrospectively, 560 gated CCT images (including 60 synthetic images) performed at our institution were used to train AI-model, which can automatically divide heart region into five areas belonging to left main (LM), left anterior descending (LAD), circumflex (LCX), right coronary artery (RCA), and another. Total and vessel-specific CAC score (CACS) in each scan were manually evaluated. AI-model was trained with novel Heart-labelling method via DL according to the manual-derived results. Then, another 409 gated CCT images obtained in our institution were used for model validation. The performance of present AI-model was tested using another external cohort of 400 gated CCT images of Stanford Center for Artificial Intelligence of Medical Imaging by comparing with the ground truth. The overall accuracy of the AI-model for total CACS classification was excellent with Cohen's kappa of k = 0.89 and 0.95 (validation and test, respectively), which surpasses previous research of k = 0.89. Bland-Altman analysis showed little difference in individual total and vessel-specific CACS between AI-derived CACS and ground truth in test cohort (mean difference [95% confidence interval] were 1.5 [-42.6, 45.6], -1.5 [-100.5, 97.5], 6.6 [-60.2, 73.5], 0.96 [-59.2, 61.1], and 7.6 [-134.1, 149.2] for LM, LAD, LCX, RCA, and total CACS, respectively). Conclusion: Present Heart-labelling method provides a further improvement in fully automated, total, and vessel-specific CAC quantification on gated CCT.

Coronary Artery Vorticity to Predict Functional Plaque Progression in Participants with Type 2 Diabetes Mellitus.

Purpose: To investigate whether vorticity could predict functional plaque progression better than high-risk plaque (HRP) and lesion length (LL) in individuals with type 2 diabetes mellitus. Materials and Methods: This single-center prospective study included 61 participants (mean age, 61 years ± 9 [SD]; 43 male participants) who underwent serial coronary CT angiography at 2 years, with 20%-70% stenosis at initial CT between October 2015 and March 2020. The number of the following HRP characteristics was recorded: low attenuation, positive remodeling, spotty calcification, and napkin-ring sign. Vorticity was calculated using a mesh-free simulation. A decrease in CT fractional flow reserve larger than 0.05 indicated functional progression. Models using HRP and LL and vorticity were compared using receiver operating characteristic curve analysis. Results: Of the 94 vessels evaluated, 25 vessels (27%) showed functional progression. Vessels with functional progression showed higher vorticity at distal stenosis (984 sec-1; IQR: 730-1253 vs 443 sec-1; IQR: 295-602; P < .001) than vessels without progression. The area under the receiver operating characteristic curve of vorticity (0.91; 95% CI: 0.84, 0.97) was higher than that of HRP and LL (0.69; 95% CI: 0.56, 0.82; P < .01). Diagnostic accuracy of vorticity (85%; 80 of 94 vessels; 95% CI: 76, 92) was higher than that of HRP and LL (72%; 68 of 94 vessels; 95% CI: 62, 81; P = .004). Conclusion: In participants with type 2 diabetes mellitus, vorticity at distal stenosis was a better predictor of functional plaque progression than HRP and LL.Keywords: Coronary Artery, Vorticity, Functional Plaque Progression, Type 2 Diabetes, Vasculature, CT Angiography, Computational Fluid Dynamics, Fractional Flow Reserve Supplemental material is available for this article. © RSNA, 2023.

First validation of stress myocardial perfusion scintigraphy using a novel reconstruction process.

BACKGROUND: A new image reconstruction process termed the MUS method (masking process on unsmoothed images) was developed to eliminate artifacts, especially those in the inferior wall. We compared diagnostic performance between the MUS and conventional method in stress myocardial perfusion SPECT (MPS). METHODS: Enrolled were 126 patients who underwent stress-rest MPS with 99 m Tc-MIBI. Patients were divided into two groups: 91 with < 50% stenosis in the RCA or LCX (non-ischemia group) and 35 patients with ≥ 90% stenosis or FFR-positive in the RCA (ischemia group), according to coronary CT or coronary angiography within 3 months of MPS. Ischemic heart disease (IHD) was considered positive when the summed difference score of five segments corresponding to the inferior wall region was ≥ 2. RESULTS: Sensitivity was comparable between the MUS method and the conventional method (ordered subset expectation maximization; OSEM) (51% vs 54%, respectively; (p = 0.366), specificity was significantly higher using the MUS method (87% vs 77%, respectively; p < 0.05), and diagnostic performance was higher using the MUS method (area under curve [AUC], conventional 0.61 vs. MUS 0.69, p = 0.138). In evaluation of 87 patients after excluding 39 who received additional prone imaging, sensitivity using the MUS method was 44%, which was comparable to 44% using the conventional method but specificity was 90%, which was significantly higher than 77% using the conventional method (p < 0.05). The diagnostic performance of the MUS method was higher (AUC, conventional 0.60 vs. MUS 0.67, p = 0.185). CONCLUSION: Use of the MUS method improved specificity in diagnosis of IHD while maintaining sensitivity, compared with the conventional method. The MUS method can achieve an improvement in diagnostic accuracy equivalent to the supine position, particularly in patients who have difficulty performing the prone position, without increasing the patient burden.

Validation and clinical impact of novel pericoronary adipose tissue measurement on ECG-gated non-contrast chest CT.

BACKGROUND AND AIMS: We aimed to develop a method for quantifying pericoronary adipose tissue (PCAT) on electrocardiogram (ECG)-gated non-contrast CT (NC-PCAT) and validate its efficacy and prognostic value. METHODS: We retrospectively studied two independent cohorts. PCAT was quantified conventionally. NC-PCAT was defined as the mean CT value of epicardial fat tissue adjacent to right coronary artery ostium on ECG-gated non-contrast CT. In cohort 1 (n = 300), we evaluated the correlation of two methods and the association between NC-PCAT and CT-verified high-risk plaque (HRP). We dichotomized cohort 2 (n = 333) by the median of NC-PCAT, and assessed the prognostic value of NC-PCAT for primary endpoint (all-cause death and non-fatal myocardial infarction) by Cox regression analysis. The median duration of follow-up was 2.9 years. RESULTS: NC-PCAT was correlated with PCAT (r = 0.68, p<0.0001). In multivariable logistic regression analysis, high NC-PCAT (OR:1.06; 95%CI:1.03-1.10; p = 0.0001), coronary artery calcium score (CACS) (OR:1.01 per 10 CACS increase, 95%CI:1.00-1.02; p = 0.013), and current smoking (OR:2.58; 95%CI:1.03-6.49; p = 0.044) were independent predictors of HRP. Among patients with CACS>0 (n = 193), NC-PCAT (OR:1.06; 95%CI:1.03-1.10; p = 0.0002), current smoking (OR:3.02; 95%CI:1.17-7.82; p = 0.027), and male sex (OR:2.81; 95%CI:1.06-7.48; p = 0.028) were independent predictors of HRP, whereas CACS was not (p = 0.15). Multivariable Cox regression analysis revealed high NC-PCAT as an independent predictor of the primary endpoint, even after adjustment for sex and age (HR:4.3; 95%CI:1.2-15.2; p = 0.012). CONCLUSIONS: There was a positive correlation between NC-PCAT and PCAT, with high NC-PCAT significantly associated with worse clinical outcome (independent of CACS) as well as presence of HRP.

Energy loss is related to CT fractional flow reserve progression in type 2 diabetes mellitus patients.

Background: We aimed to investigate the diagnostic value of energy loss (EL) and baseline CT fractional flow reserve (CT-FFR) computed using computational fluid dynamics to predict functional progression of coronary stenosis in patients with type 2 diabetes mellitus. Methods: This single-center prospective study included 61 patients with type 2 diabetes mellitus (mean age, 61 years ±9 [SD]; 43 men) showing 20-70 % stenosis who underwent serial coronary CT performed at 2-year interval between October 2015 and March 2020. A mesh-free simulation was performed to calculate the CT-FFR and EL. Functional progression was defined as ≥ 0.05 decrease in CT-FFR on the second coronary CT. Models using baseline CT-FFR and EL were compared by analyzing the receiver operating characteristic (ROC) curve. Results: Of the 94 vessels evaluated, 25 vessels (27 %) showed functional progression. EL at distal stenosis (ELdis) of vessels with functional progression was higher than that of vessels without functional progression (27.6 W/m3 [interquartile range (IQR): 15.0, 53.0] vs. 5.7 W/m3 [IQR: 2.3, 10.1], p < 0.001). Multivariable analysis showed that ELdis (per unit Ln(EL); odds ratio, 11.8; 95 % CI: 4.0-34.9; p < 0.001) remained as a predictor of functional progression after adjustment for diameter stenosis and baseline CT-FFR. The area under the ROC curve using ELdis (0.89; 95 % CI: 0.82-0.96) was higher than that using baseline CT-FFR (0.71; 95 % CI: 0.59-0.83; p < 0.001). Conclusion: When ELdis and baseline CT-FFR were considered, ELdis was a better predictor of functional progression of coronary stenosis.

Coronary flow disturbance assessed by vorticity as a cause of functionally significant stenosis.

OBJECTIVES: Vorticity calculated using computational fluid dynamics (CFD) could assess the flow disturbance generated by coronary stenosis. The purpose of this study was to investigate whether vorticity would be an underlying cause of functionally significant stenosis assessed by invasive fractional flow reserve (FFR). METHODS: This retrospective study included 113 patients who underwent coronary CT angiography showing intermediate stenosis and subsequent invasive FFR between December 2015 and March 2020. Vorticity at the stenosis site was calculated using a mesh-free CFD method. We also evaluated the minimum lumen area (MLA) and diameter stenosis (DS) of the lesion. Invasive FFR of ≤ 0.80 was considered functionally significant. Data were compared using Student's t-test and logistic regression analysis was performed. RESULTS: Of the evaluated 144 vessels, 53 vessels (37%) showed FFR ≤ 0.80. Vorticity of significant stenosis was significantly higher than non-significant stenosis (569 ± 78 vs. 328 ± 34 s-1, p < 0.001). A significant negative relationship was present between vorticity and invasive FFR (R2 = 0.31, p < 0.001). Multivariate logistic regression analysis including MLA and DS showed that vorticity (per 100 s-1, odds ratio: 1.36, 95% confidence interval: 1.21-1.57, p < 0.001) was a statistically significant factor to detect functional significance. The area under the receiver operating characteristic curve statistically significantly increased when vorticity was combined with DS and MLA (0.76 vs. 0.87, p = 0.001). CONCLUSIONS: Vorticity had a statistically significant negative relationship with invasive FFR independent of geometric stenosis. KEY POINTS: • Flow disturbance caused by coronary stenosis could be evaluated by calculating vorticity which is defined as the norm of the rotation of the velocity vector. • Vorticity was statistically significantly higher in stenosis with functional significance than stenosis without. • Vorticity has an additive value to detect functionally significant stenosis over geometrical stenosis.

Use of a deep-learning-based lumen extraction method to detect significant stenosis on coronary computed tomography angiography in patients with severe coronary calcification.

BACKGROUND: Coronary computed tomography angiography examinations are increasingly becoming established as a minimally invasive method for diagnosing coronary diseases. However, although various imaging and processing methods have been developed, coronary artery calcification remains a major limitation in the evaluation of the vascular lumen. Subtraction coronary computed tomography angiography (Sub-CCTA) is a method known to be able to reduce the influence of coronary artery calcification and is therefore feasible for improving the diagnosis of significant stenosis in patients with severe calcification. However, Sub-CCTA still involves some problems, such as the increased radiation dose due to plain (mask) imaging, extended breath-holding time, and misregistration due to differences in the imaging phase. Therefore, we considered using artificial intelligence instead of Sub-CCTA to visualize the coronary lumen with high calcification. Given this background, the present study aimed to evaluate the diagnostic performance of a deep learning-based lumen extraction method (DL-LEM) to detect significant stenosis on CCTA in 99 consecutive patients (891 segments) with severe coronary calcification from November 2015 to March 2018. We also estimated the impact of DL-LEM on the medical economics in Japan. RESULTS: The DL-LEM slightly improved the per-segment diagnostic accuracy from 74.5 to 76.4%, and the area under the curve (AUC) slightly improved from 0.752 to 0.767 (p = 0.030). When analyzing the 228 segments that could not be evaluated because of severe calcification on the original CCTA images, the DL-LEM improved the accuracy from 35.5 to 42.5%, and the AUC improved from 0.500 to 0.587 (p = 0.00018). As a result, DL-LEM analysis could have avoided invasive coronary angiography in 4/99 cases (per patient). From the calculated results, it was estimated that the number of exams that can be avoided in Japan in one year is approximately 747 for invasive coronary angiography, 219 for fractional flow reserve, and 248 for nuclear exam. The total amount of medical fee that could be reduced was 225,629,368 JPY. CONCLUSIONS: These findings suggest that the DL-LEM may improve the diagnostic performance in detecting significant stenosis in patients with severe coronary calcification. In addition, the results suggest that not a small medical economic effect can be expected.

Clinical features and predictors of outcome in patients with acute myocardial infarction complicated by out-of-hospital cardiac arrest.

BACKGROUND: Although short-term mortality of acute myocardial infarction (AMI) has decreased dramatically in the past few decades, sudden cardiac arrest remains a serious complication. The aim of the study was to assess the clinical characteristics and predictors of prognosis in AMI patients who experienced out-of-hospital cardiac arrest (OHCA). METHODS: We retrospectively registered consecutive AMI patients who were treated with emergency percutaneous coronary intervention (PCI) between 2004 and 2017. Clinical characteristics and outcomes were compared between patients with OHCA and those without OHCA. RESULTS: Among 2101 AMI patients, 95 (4.7%) presented with OHCA. Younger age (odds ratio [OR]: 0.95; 95% confidence interval [CI]: 0.93-0.97; p < 0.0001), absence of diabetes mellitus (OR, 0.51; 95% CI, 0.30-0.85; p = 0.01) or dyslipidemia (OR, 0.56; 95% CI, 0.36-0.88; p = 0.01), left main trunk (LMT) or left anterior descending artery (LAD) as the culprit lesion (OR, 3.26; 95% CI, 1.99-5.33; p < 0.0001), and renal deficiency (OR, 3.64; 95% CI, 2.27-5.84; p < 0.0001) were significantly associated with incidence of OHCA. Thirty-day mortality was 32.6% in patients with OHCA and 4.5% in those without OHCA. Multivariate logistic analysis revealed LMT or LAD as the culprit lesion (OR, 12.18; 95% CI, 2.27-65.41; p = 0.004), glucose level (OR, 1.01; 95% CI, 1.00-1.01; p = 0.01), and renal deficiency (OR, 3.35; 95% CI, 1.07-10.53; p = 0.04) as independent predictors of 30-day mortality among AMI patients with OHCA. CONCLUSIONS: In patients with AMI who underwent emergency PCI, 30-day mortality was six times greater in those having presented initially with OHCA compared with those without OHCA. Younger age, absence of diabetes mellitus or dyslipidemia, LMT or LAD as the culprit lesion, and renal deficiency were independent predictors of OHCA. OHCA patient with higher blood glucose level on admission, LMT or LAD as the culprit lesion, or renal deficiency showed worse clinical outcomes.

Prognostic value of the optimal measurement location of on-site CT-derived fractional flow reserve.

BACKGROUND: On-site computed tomography-derived fractional flow reserve (CT-FFR), using fluid structure interaction during multiple optimal diastolic phases, is of incremental diagnostic value. However, few studies have investigated prognosis, with the appropriate measurement location of CT-FFR, as a stand-alone modality. The aim of the present study was to assess the clinical impact on CT-FFR with an appropriate measurement. METHODS: A total of 370 consecutive patients (68 ±â€¯10 years, 75% male) who underwent coronary CT angiography (CCTA), showing 50-90% stenosis in at least one major epicardial vessel, were retrospectively analyzed and followed up for a median 2.9 years. CT-FFR values were measured at three points: 1 to 2 cm distal to the target lesion (CT-FFR1cm, 2cm) and the vessel terminus (CT-FFRlowest), and a CT-FFR value ≤0.80 was considered to be abnormal. The endpoint was major adverse cardiovascular events (MACE), a composite of cardiac death, non-fatal myocardial infarction, and unplanned revascularization. RESULTS: The incidence of MACE was 6.8% (25/370 patients). The Kaplan-Meier survival analysis in negative CT-FFR1/2cm revealed no significant difference in MACE between negative and positive CT-FFRlowest [p = 0.11/0.23 (1/2 cm vs lowest)]. Among 221 patients who did not undergo planned revascularization within 90 days of CCTA, no significant differences were noted in the incidence of MACE between negative and positive CT-FFRlowest (p = 0.11). In contrast, the risk of MACE was significantly higher with positive CT-FFR1/2cm [p = 0.0198/0.0002 (1/2 cm)]. CONCLUSIONS: In terms of the prognosis of patients with moderate to severe stenosis on CCTA, CT-FFR measured 1 to 2 cm distal to the target lesion may be feasible for the safe deferral of unnecessary invasive coronary angiography. Moreover, CT-FFR1/2cm showed better risk stratification than CT-FFRlowest based on future adverse cardiac events.

Clinical significance of 123I-BMIPP washout rate in patients with uncertain chronic heart failure.

BACKGROUND: Recently, triglyceride deposit cardiomyovasculopathy (TGCV) with defective intracellular lipolysis was found to be a disease that causes heart failure. As a diagnostic criterion for TGCV, an Iodaine-123-ß-methyl iodophenyl-pentadecanoic acid washout rate (BMIPP WOR) of < 10% is used, but its clinical significance in patients with heart failure remains to be clarified. METHODS: In 62 hospitalized patients with chronic heart failure, 123I-BMIPP myocardial single-photon emission computed tomography (SPECT) was performed predischarge state. The prevalence of TGCV was investigated. Subsequently, follow-up was conducted for ≥ 90 days (mean: 724.6 ± 392.7 days), and the association between the BMIPP WOR and cardiac events was examined, establishing all-cause mortality and admission due to heart failure as endpoints. RESULTS: Of the 62 patients, the WOR was < 10% in 41 (66.1%). Of these, 26 (41.9%) were diagnosed with definite TGCV. Furthermore, cardiac events were noted in 12 patients (19.4%). Analysis with Cox proportional hazards models showed that the BMIPP WOR < 4.5% was a significant event-predicting factor [HR 4.29, 95% CI: 1.20-16.87; p = 0.0245]. On a Kaplan-Meier curve, the WOR was 4.5%; there was a significant difference in the incidence of events (p = 0.0298). CONCLUSION: In the predischarge state of heart failure, 123I-BMIPP myocardial SPECT was performed. In approximately 40% of the patients, a diagnosis of TGCV was made. The results suggested that the BMIPP WOR is useful for predicting the prognosis of chronic heart failure patients regardless of TGCV.

Identification of Risk Factors for Coronary Artery Disease in Asymptomatic Patients with Type 2 Diabetes Mellitus.

BACKGROUND: Patients with diabetes mellitus (DM) are a high-risk group for coronary artery disease (CAD). In the present study, we investigated predictive factors to identify patients at high risk of CAD among asymptomatic patients with type 2 DM based on coronary computed tomographic angiography (CCTA) findings. METHODS: A single-center prospective study was performed on 452 consecutive patients with type 2 DM who were provided with a weekly hospital-based diabetes education program between 3 October 2015, and 31 March 2020. A total of 161 consecutive asymptomatic patients (male/female: 111/50, age: 57.3 ± 9.3 years) with type 2 DM without any known CAD underwent CCTA. Based on conventional coronary risk factors and non-invasive examination, i.e., measurement of intima-media thickness, subcutaneous and visceral fat area, a stress electrocardiogram test, and the Agatston score, patients with obstructive CAD, CT-verified high-risk plaques (CT-HRP), and optimal revascularization within 90 days were evaluated. RESULTS: Current smoking (OR, 4.069; 95% C.I., 1.578-10.493, p = 0.0037) and the Agatston score ≥100 (OR, 18.034; 95% C.I., 6.337-51.324, p = 0.0001) were independent predictive factors for obstructive CAD, while current smoking (OR, 5.013; 95% C.I., 1.683-14.931, p = 0.0038) was an independent predictive factor for CT-HRP. Furthermore, insulin treatment (OR, 5.677; 95% C.I., 1.223-26.349, p = 0.0266) was the only predictive factor that correlated with optimal revascularization within 90 days. CONCLUSIONS: In asymptomatic patients with type 2 DM, current smoking, an Agatston score ≥100, and insulin treatment were independent predictive factors of patients being at high-risk for CAD. However, non-invasive examinations except for Agatston score were not independent predictors of patients being at high risk of CAD.

Impact of Lipoprotein(a) as a Residual Risk Factor in Long-Term Cardiovascular Outcomes in Patients With Acute Coronary Syndrome Treated With Statins.

The association between lipoprotein(a) (Lp[a]) levels and cardiovascular disease has been reported. However, it is still uncertain whether Lp(a) concentration could be a residual risk factor for cardiovascular events after acute coronary syndrome (ACS). The aim of the present study is to evaluate the impact of Lp(a) on long-term cardiovascular outcomes in patients with ACS treated with statins. We studied 1,758 consecutive patients with ACS who underwent emergency percutaneous coronary intervention between 2008 and 2017. We finally enrolled 1,131 patients for whom Lp(a) data were available and who were treated with statins at discharge. Patients were divided into 2 groups according to Lp(a) levels (median Lp(a) 15.0 mg/100 ml). The primary end points were major adverse cardiac events (MACEs), composite of all-cause death, and myocardial infarction up to 5 years. Overall, 107 MACEs (9.5%) were identified. The cumulative incidence of MACE was significantly higher in the high Lp(a) group than the low Lp(a) group (log-rank p = 0.01). After adjustment for other cardiovascular risk factors, the high Lp(a) group had a significantly higher risk of MACE (hazard ratio 1.66, 95% confidence interval 1.05 to 2.61, p = 0.03). Multivariate Cox hazard analysis also showed that increasing Lp(a) as a continuous variable was associated with the incidence of MACE (hazard ratio 1.35 per log Lp[a] 1 increase, 95% confidence interval 1.07 to 1.72, p = 0.01). In conclusion, high Lp(a) level is significantly associated with long-term cardiovascular outcomes in patients with ACS treated with statins after primary percutaneous coronary intervention and is likely to be a potential biomarker for residual risk prediction of future clinical events.

Feasibility of CT Angiography-derived Kinetic Energy of Coronary Flow to Improve the Detection of Hemodynamically Significant Coronary Stenosis.

Purpose: To investigate whether coronary flow kinetic energy has incremental value over simulated fractional flow reserve (sFFR) in diagnosing hemodynamically significant stenosis assessed with coronary CT angiography and invasive fractional flow reserve (FFR). Materials and Methods: This single-center retrospective study included 113 patients (mean age, 68 years ± 9 [SD]; 80 men) who underwent coronary CT angiography showing intermediate stenosis (30%-70% stenosis) and subsequent invasive FFR between December 2015 and March 2020. Kinetic energy was calculated using proximal coronary diameter and myocardial mass of the stenotic region. A mesh-free simulation was performed to calculate the sFFR. Invasive FFR of 0.80 or less indicated hemodynamically significant stenosis. Models using diameter stenosis, kinetic energy, and sFFR were compared by analyzing the receiver operating characteristic curve. Results: Of the 144 vessels evaluated, 53 vessels (37%) had hemodynamically significant stenosis. Kinetic energy of vessels with significant stenosis was higher than that of vessels with nonsignificant stenosis (79 mJ/kg [IQR, 58-104 mJ/kg] vs 36 mJ/kg [IQR, 23-59 mJ/kg]; P < .001). Multivariable analysis including diameter stenosis and sFFR showed that kinetic energy (per 20 mJ/kg; odds ratio, 1.92; 95% CI: 1.37, 2.95; P < .001) was a predictor of hemodynamically significant stenosis. Adding kinetic energy to diameter stenosis and sFFR improved the area under the receiver operating characteristic curve from 0.89 (95% CI: 0.84, 0.95) to 0.93 (95% CI: 0.89, 0.97) (P = .04). Conclusion: Kinetic energy had incremental value over sFFR in detecting hemodynamically significant stenosis assessed with invasive FFR.Keywords: Coronary CT Angiography, Coronary Arteries, Fractional Flow Reserve, Kinetic Energy, Cardiac Supplemental material is available for this article © RSNA, 2022.

A phantom and in vivo simulation of coronary flow to calculate fractional flow reserve using a mesh-free model.

Moving particle semi-implicit (MPS) method is a mesh-free method to perform computational fluid dynamics (CFD). The purpose of this study was to calculate the simulated fractional flow reserve (sFFR) using a coronary stenosis model, and to validate the MPS-derived sFFR against invasive FFR using clinical coronary CT data. Coronary flow simulation included 21 stenosis models with stenosis ranging 30-70%. Patient coronary analysis was performed in 76 consecutive patients (100 vessels) who underwent coronary CT angiography and subsequent invasive FFR between November 2016 and March 2020. Accuracy of sFFR and CT angiography for diagnosis of invasive FFR ≤ 0.80 was compared. Quantitative morphological stenosis data of CT angiography were also obtained. Area stenosis showed a good correlation to sFFR (R2 = 0.996, p < 0.001) in coronary stenosis models. In the patient study, the mean FFR value was 0.82 ± 0.10, and 37 out of 100 vessels showed FFR ≤ 0.80. FFR and sFFR values showed a good correlation (R2 = 0.59, p < 0.001) with a slight underestimation of sFFR as compared with FFR (mean difference - 0.015 ± 0.096, p = 0.12). The sensitivity, specificity, positive predictive value, and negative predictive value of sFFR to predict FFR ≤ 0.80 was 86%, 89%, 82%, 92%, respectively. The accuracy to predict FFR ≤ 0.80 using sFFR was greater than using diameter stenosis and minimum lumen area (88% vs. 74%, p = 0.008). CFD using the MPS method showed feasible results validated against invasive FFR. The accuracy to predict significant stenosis was higher than morphological stenosis.

Incremental Diagnostic Value of CT Fractional Flow Reserve Using Subtraction Method in Patients with Severe Calcification: A Pilot Study.

Although on-site workstation-based CT fractional flow reserve (CT-FFR) is an emerging method for assessing vessel-specific ischemia in coronary artery disease, severe calcification is a significant factor affecting CT-FFR's diagnostic performance. The subtraction method significantly improves the diagnostic value with respect to anatomic stenosis for patients with severe calcification in coronary CT angiography (CCTA). We evaluated the diagnostic capability of CT-FFR using the subtraction method (subtraction CT-FFR) in patients with severe calcification. This study included 32 patients with 45 lesions with severe calcification (Agatston score >400) who underwent both CCTA and subtraction CCTA using 320-row area detector CT and also received invasive FFR within 90 days. The diagnostic capabilities of CT-FFR and subtraction CT-FFR were compared. The sensitivities, specificities, positive predictive values (PPVs), and negative predictive values (NPVs) of CT-FFR vs. subtraction CT-FFR for detecting hemodynamically significant stenosis, defined as FFR ≤ 0.8, were 84.6% vs. 92.3%, 59.4% vs. 75.0%, 45.8% vs. 60.0%, and 90.5% vs. 96.0%, respectively. The area under the curve for subtraction CT-FFR was significantly higher than for CT-FFR (0.84 vs. 0.70) (p = 0.04). The inter-observer and intra-observer variabilities of subtraction CT-FFR were 0.76 and 0.75, respectively. In patients with severe calcification, subtraction CT-FFR had an incremental diagnostic value over CT-FFR, increasing the specificity and PPV while maintaining the sensitivity and NPV with high reproducibility.

Comparison of diagnostic performance in on-site based CT-derived fractional flow reserve measurements.

BACKGROUND: Computed tomography fractional flow reserve (CT-FFR), which can be acquired on-site workstation using fluid structure interaction during the multiple optimal diastolic phase, has an incremental diagnostic value over conventional coronary computed tomography angiography (CCTA). However, the appropriate location for CT-FFR measurement remains to be clarified. METHOD: A total of 115 consecutive patients with 149 vessels who underwent CCTA showing 30-90% stenosis with invasive FFR within 90 days were retrospectively analyzed. CT-FFR values were measured at three points: 1 and 2 cm distal to the target lesion (CT-FFR1cm, 2cm) and the vessel terminus (CT-FFRlowest). The diagnostic accuracies of CT-FFR ≤ 0.80 for detecting hemodynamically significant stenosis, defined as invasive FFR ≤ 0.80, were compered. RESULT: Fifty-five vessels (36.9%) had invasive FFR ≤ 0.80. The accuracy and AUC for CT-FFR1cm and 2cm were comparable, while the AUC for CT-FFRlowest was significantly lower than CT-FFR1cm and 2cm. (lowest/1cm, 2 cm = 0.68 (95 %CI 0.63-0.73) vs 0.79 (0.72-0.86, p = 0.006), 0.80 (0.73-0.87, p = 0.002)) The sensitivity and negative predictive value of CT-FFRlowest were 100%. The reclassification rates from positive CT-FFRlowest to negative CT-FFR1cm and 2cm were 55.7% and 54.2%, respectively. CONCLUSION: The diagnostic performance of CT-FFR was comparable when measured at 1-to-2 cm distal to the target lesion, but significantly higher than CT-FFRlowest. The lesion-specific CT-FFR could reclassify false positive cases in patients with positive CT-FFRlowest, while all patients with negative CT-FFRlowest were diagnosed as negative by invasive FFR.

Clinical Characteristics and Long-Term Outcomes of Patients with Acute Coronary Syndrome During Travel.

Cardiovascular disease is a major cause of death among travelers, but the clinical characteristics and clinical outcomes of patients who develop acute coronary syndrome (ACS) while traveling have not been assessed. We evaluated 2548 patients with ACS who underwent primary percutaneous coronary intervention (PCI) between 1999 and 2015 and compared the incidences of all-cause and cardiac death during follow-up between travelers and locals. We assessed 192 (7.5%) patients who developed ACS while traveling. These patients were younger and had a higher prevalence of ST-elevation myocardial infarction than local patients. During a median follow-up period of 5.3 years, 632 (24.8%) all-cause deaths were identified, including 310 cardiac deaths (12.2%). Kaplan-Meier analysis revealed that the cumulative incidence of all-cause death was significantly lower among the travelers than locals (P = 0.001, log-rank test). Multivariate Cox hazard analysis revealed that travel was significantly associated with a lower rate of all cause death (hazard ratio, 0.53; 95% confidence interval, 0.33-0.80; P = 0.002). Cardiac mortality did not significantly differ between travelers and locals (P = 0.29). Patients with ACS treated with primary PCI while traveling had more favorable long-term clinical outcomes than local patients. Appropriate initial treatments and secondary preventions might improve the prognosis of travelers.