Noninvasive transthoracic doppler flow velocity and invasive thermodilution to assess coronary flow reserve.

Background: Coronary flow reserve (CFR) provides prognostication and coronary physiological information, including epicardial coronary stenosis and microvascular function. The relationship between stress transthoracic Doppler echocardiography (TDE)-derived coronary flow velocity reserve (CFRS-TDE) and thermodilution-derived coronary flow reserve (CFRthermo) before and after elective percutaneous coronary intervention (PCI) remains unclear. Methods: This single-center prospective registry study evaluated patients who underwent fractional flow reserve (FFR)-guided elective PCI for left anterior descending artery (LAD) lesions with wire-based invasive physiological measurements and pre- and post-PCI stress TDE examinations. Results: A total of 174 LAD lesions from 174 patients were included in the final analysis. A modest correlation was detected between the pre-PCI CFRS-TDE and the pre-PCI CFRthermo (r=0.383, P<0.001). The frequently used CFRS-TDE threshold of 2.0 corresponded to a pre-PCI CFRthermo of 2.18. Pre-PCI CFRS-TDE underestimated pre-PCI CFRthermo [1.89 (1.44-2.31) vs. 2.05 (1.38-2.93), P<0.001]. Both CFRS-TDE and CFRthermo increased significantly post-PCI [pre-PCI CFRS-TDE 1.89 vs. post-PCI CFRS-TDE 2.33, P<0.001; pre-PCI CFRthermo 2.05 (1.38-2.93) vs. post-PCI CFRthermo 2.59 (1.63-3.55), P<0.001]. In contrast, there was no significant relationship between changes in CFRS-TDE and changes in CFRthermo after PCI (r=0.008, P=0.915) or between post-PCI CFRS-TDE and post-PCI CFRthermo (r=0.054, P=0.482). Conclusions: Pre-PCI CFRS-TDE and CFRthermo are modestly correlated, but post-PCI CFRS-TDE and CFRthermo have no correlation. CFRS-TDE and CFRthermo are not interchangeable, particularly post-PCI, suggesting that the two metrics represent different coronary physiologies after PCI.

Combined Assessment of Fractional Flow Reserve and Coronary Flow Velocity Reserve after Drug-Eluting Stent Implantation.

BACKGROUND: Coronary flow velocity reserve (CFVR) can be measured noninvasively using stress transthoracic Doppler echocardiography (S-TDE). The prognostic significance of S-TDE-derived CFVR after percutaneous coronary intervention (PCI) remains unknown. The aim of this study was to investigate the prognostic value of post-PCI CFVR and its additional efficacy to fractional flow reserve (FFR) in patients undergoing elective PCI. METHODS: A retrospective study was conducted involving 187 consecutive patients with chronic coronary syndrome who underwent elective PCI guided by FFR for the left anterior descending coronary artery. Pre- and post-PCI wire-based FFR and CFVR assessments of the left anterior descending coronary artery using S-TDE were performed in all patients. The association between post-PCI clinical and physiologic parameters and major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, heart failure, and unplanned remote target vessel revascularization, was evaluated. RESULTS: Three-quarters of patients exhibited CFVR increase after PCI, while all patients showed FFR improvement. During a median follow-up period of 1.5 years, MACE occurred in 21 patients (11.2%). Among clinical demographics, patients with MACE had higher levels of N-terminal pro-brain natriuretic peptide compared with those without MACE (median, 615 pg/mL [interquartile range, 245-1,500 pg/mL] vs 180 pg/mL [interquartile range, 70-559 pg/mL]; P = .010). Post-PCI S-TDE-derived CFVR was lower in patients with MACE, while post-PCI FFR showed a nonsignificant tendency to be lower in patients with MACE. In a multivariable analysis, higher NT-proBNP (adjusted hazard ratio, 1.33; 95% CI, 1.02-1.74; P = .038), post-PCI CFVR ≤ 2.0 (adjusted hazard ratio, 2.93; 95% CI, 1.16-7.40; P = .023), and post-PCI FFR ≤ 0.82 (adjusted hazard ratio, 3.93; 95% CI, 1.52-10.18; P = .005) were independently associated with MACE. CONCLUSIONS: In patients with chronic coronary syndrome who underwent successful elective PCI for left anterior descending coronary artery, the combined assessment of S-TDE-derived post-PCI CFVR and post-PCI FFR provided a significant association with the occurrence of MACE.

Diagnostic value of computed tomography myocardial perfusion imaging to detect coexisting microvascular dysfunction in patients with obstructive epicardial coronary artery disease.

Background: Computed tomography myocardial perfusion (CT-MP) has reported usefulness in assessing hemodynamically significant epicardial coronary artery lesions. However, the diagnostic ability of the absolute coronary flow using CT-MP to detect coronary microvascular dysfunction (CMD) remains elusive. This prospective cohort study aimed to assess the diagnostic value of CT-MP in evaluating coexisting CMD in patients with functionally significant epicardial coronary stenosis and to analyze the predictive factors of lesions with CMD. Methods: Sixty-eight patients with chronic coronary syndrome (CCS) and de novo single functionally significant stenosis [fractional flow reserve (FFR) ≤0.80] were studied. CMD was defined as an index of microcirculatory resistance ≥25. We compare clinical background and CT-MP findings between patients with and without CMD (CMD, n=29; non-CMD, n=39). CT-MP, and quantitative and qualitative plaque assessments were included in computed tomography angiography assessment. Logistic regression analysis was performed to predict CMD. Results: FFR, invasive wire-derived coronary flow reserve (CFRwire) and index of microcirculatory resistance were 0.68 [interquartile range (IQR), 0.59-0.74], 1.71 (IQR, 1.24-2.88), and 22.6 (IQR, 15.1-34.5), respectively. The rest and hyperemic-myocardial blood flow (MBF) and CT-MP-derived CFR (CFRCT-MP) were 0.83 (0.64-1.03) mL/min/g, 2.14 (1.30-2.92) mL/min/g, and 2.19 (1.44-3.37), respectively. In the territories with CMD, hyperemic-MBF was significantly lower than in those without [1.68 (IQR, 0.84-2.44) vs. 2.31 (IQR, 1.67-3.34) mL/min/g, P=0.015] and the prevalence of CFRCT-MP <2.0 was higher in the lesions with CMD than in those without (62.1% vs. 28.2%, P=0.011), while FFR values were similar. Fibrofatty and necrotic core component volume was greater in the vessels with CMD than in those without [31.8 (IQR, 19.0-48.9) vs. 25.1 (IQR, 17.2-32.1) mm3, P=0.045]. Multivariable logistic regression analysis showed that hyperemic-MBF and fibrofatty and necrotic core component volume were independent predictors of CMD territories [odds ratio (OR) =0.583; 95% confidence interval (CI): 0.355-0.958; P=0.033 and OR =1.040; 95% CI: 1.010-1.070; P=0.011]. Conclusions: Quantitative assessment of absolute coronary flow using pre-percutaneous coronary intervention (PCI) CT-MP, and comprehensive plaque analysis using computed tomography angiography may help detect coexisting subtended microvascular dysfunction in territories with functionally significant epicardial coronary lesions. Further studies are required to elucidate the clinical significance of coexisting CMD in patients with CCS undergoing PCI.

Prognostic Implications of Fractional Flow Reserve and Coronary Flow Reserve After Drug-Eluting Stent Implantation.

BACKGROUND: Fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) provides prognostic information, but limited data are available regarding prognostication using post-PCI coronary flow reserve (CFR). In this study we aimed to assess the prognostic value of post-procedural FFR and CFR for target vessel failure (TVF) after PCI.Methods and Results: This lesion-based post-hoc pooled analysis of previously published registry data involved 466 patients with chronic coronary syndrome with single-vessel disease who underwent pre- and post-PCI FFR and CFR measurements, and were followed-up to determine the predictors of TVF. The prognostic value of post-PCI CFR and FFR was compared with that of FFR or CFR alone. Post-PCI FFR/CFR discordant results were observed in 42.5%, and 10.3% of patients had documented TVF. Receiver-operating characteristic curve analysis revealed that the optimal cutoff values of post-PCI FFR and CFR to predict the occurrence of TVF were 0.85 and 2.26, respectively. Significant differences in TVF were detected according to post-PCI FFR (≤0.85 vs. >0.85, P=0.007) and post-PCI CFR (<2.26 vs. ≥2.26, P<0.001). Post-PCI FFR ≤0.85 and post-PCI CFR <2.26 were independent prognostic predictors. CONCLUSIONS: After PCI completion, discordant results between FFR and CFR were not uncommon. Post-PCI CFR categorization showed incremental prognostic value for predicting TVF independent of post-PCI FFR risk stratification.

A novel coronary angiographic index for predicting correlation between fractional flow reserve and resting full-cycle ratio.

OBJECTIVES: The discordant results between fractional flow reserve (FFR) and resting full-cycle ratio (RFR) and the influence of angiographic characteristics on their correlation have not been sufficiently investigated. We aimed to identify angiographic characteristics that can predict FFR and RFR correlations using a novel angiographic scoring system. METHODS: This retrospective analysis included 220 patients with 252 intermediate coronary lesions assessed using FFR and RFR. Each branch distal to the target lesion was scored based on the vessel diameter (0 points: < 1.5 mm, 1 point: 1.5-2.0 mm, and 2 points: > 2.0 mm) measured using quantitative coronary angiography. The angiographic score was calculated by adding these scores. RESULTS: In a propensity score-matched cohort including 84 lesions (42 lesions in each low-and high-angiographic score group), the correlation between FFR and RFR in the high-angiographic score group (>4) was weaker than that in the low-score group (≤4) (Spearman's correlation: r = 0.44 vs. r = 0.80, P  < 0.01). Considering a threshold of functional myocardial ischemia as FFR ≤ 0.80 and RFR ≤ 0.89, the low-angiographic score group showed a significantly lower discordance rate of abnormal FFR/normal RFR than the high-angiographic score group (7.1% vs. 23.8%, P  = 0.03), whereas the discordance rates of normal FFR/abnormal RFR were similar in both groups (7.1% vs. 9.5%, P  = 0.69). CONCLUSION: This retrospective analysis highlights the influence of angiographic characteristics on the correlation between FFR and RFR. Our simple angiographic assessment method may be useful for interpreting physiological evaluations in daily clinical practice.

Prognostic utility of the pericoronary fat attenuation index in patients with takotsubo cardiomyopathy.

BACKGROUND: The etiology of takotsubo cardiomyopathy (TCM) remains poorly understood and no optimal management strategy has been established. Identification of features associated with poor outcomes may improve the prognosis of patients with TCM. We aimed to identify the predictors of poor prognosis in patients with TCM using coronary computed tomography angiography (CCTA). METHODS: We enrolled consecutive patients with TCM who underwent CCTA during the acute disease phase. The pericoronary fat attenuation index (FAI) of adipose tissue was obtained from CCTA images. Major adverse cardiac and cerebrovascular events (MACCE) were defined as all-cause death, non-fatal myocardial infarction, stroke, rehospitalization due to congestive heart failure, and TCM recurrence. The relationships between patient characteristics and CCTA findings were compared between patients with and without MACCE. RESULTS: A total of 52 patients were included (10 men [19.2%]; mean age, 71 years). After a median follow-up of 23 months, MACCE had developed in 10 patients (19.2%). There were significant differences in clinical characteristics [including the three-vessel mean FAI (FAI-mean)] between patients with and without MACCE. Univariate Cox regression analyses showed that FAI-mean â€‹≥ â€‹-68.94 Hounsfield units (cut-off value derived from receiver operating characteristic curve analysis) (hazard ratio [HR], 13.52; 95% confidence interval [CI], 1.705-107.2; p â€‹= â€‹0.014) and NT-proBNP (HR, 1.000; 95% CI, 1.000-1.000; p â€‹= â€‹0.022) were significant predictors of MACCE. FAI-mean â€‹≥ â€‹-68.94 HU was significantly associated with MACCE (chi-squared statistic â€‹= â€‹10.3, p â€‹= â€‹0.001). CONCLUSION: In patients with TCM, a higher FAI-mean was significantly associated with poorer outcomes independent of the conventional risk factors.

Identification of Optical Coherence Tomography-Defined Coronary Plaque Erosion by Preprocedural Computed Tomography Angiography.

Background A previous coronary computed tomography (CT) angiographic study failed to discriminate optical coherence tomography-defined intact fibrous cap culprit lesions (IFC group) from those with ruptured fibrous caps (RFC group) in patients with coronary artery disease. This study aimed to evaluate the diagnostic efficacy of preprocedural coronary CT imaging in identifying subsequently performed optical coherence tomography-defined plaque rupture or erosion at culprit lesions in patients with non-ST-segment-elevation acute myocardial infarction. Methods and Results This study used data from 2 recently published studies that tested the hypothesis that coronary CT angiography (CCTA) before percutaneous coronary intervention may provide diagnostic information on the high-risk atherosclerotic burden in patients with non-ST-segment-elevation acute myocardial infarction. In the analysis of 186 patients, optical coherence tomography identified 106 RFC plaques and 80 IFC plaques as the culprit lesions. On CT, the prevalence of low-attenuation plaque, positive remodeling, napkin-ring sign, and spotty calcification were all significantly lower in the IFC group. The culprit vessel pericoronary adipose tissue inflammation and coronary artery calcium scores were significantly lower in the IFC group than in the RFC group. The absence of low-attenuation plaque, napkin-ring sign, zero coronary artery calcium, and low pericoronary adipose tissue inflammation were independent predictors of IFC. When stratified into 5 subgroups according to the number of these 4 CT factors, the prevalence of IFC was 8.3%, 20.8%, 44.6%, 75.6%, and 100% (P<0.001), respectively. Conclusions Preprocedural comprehensive coronary CT imaging, including coronary artery calcium and pericoronary adipose tissue inflammation assessment, can accurately and noninvasively identify optical coherence tomography-defined IFC or RFC culprit lesions.

Microvascular resistance reserve in the presence of functionally significant epicardial stenosis and changes after revascularization.

In the presence of functionally significant epicardial lesions, microvascular resistance reserve (MRR) calculation needs incorporation of collateral flow. Coronary fractional flow reserve (FFRcor ) requiring coronary wedge pressure (Pw ), which is an essential part of the true MRR calculation, is reportedly estimated by myocardial FFR (FFRmyo ) not requiring Pw measurement. We sought to find an equation to calculate MRR without the need for Pw . Furthermore, we assessed changes in MRR after percutaneous coronary intervention (PCI). An equation to estimate FFRcor was developed from a cohort of 230 patients who underwent physiological measurements and PCI. Corrected MRR was calculated using this equation and compared with true MRR in 115 patients of the different set of the validation cohort. True MRR was calculated using FFRcor . FFRcor and FFRmyo showed a strong linear relationship (r2  = 0.86) and an equation was FFRcor  = 1.36 × FFRmyo - 0.34. This equation provided no significant difference between corrected MRR and true MRR in the validation cohort. Pre-PCI lower coronary flow reserve and higher index of microcirculatory resistance were independent predictors of pre-PCI decreased true MRR. True MRR significantly decreased after PCI. In conclusion, MRR can be accurately corrected using an equation for FFRcor estimation without Pw .

Leadless pacemaker implantation sites confirmed by computed tomography and their parameters and complication rates.

BACKGROUND: Implantations of leadless pacemakers in the septum lower the risk of cardiac perforation. However, the relationship between the implantation site and the success rate, complication rate, and pacemaker parameters are not well-investigated. METHODS: Patients who underwent leadless pacemaker implantation with postprocedural computed tomography (CT) between September 2017 and November 2020 were analyzed. Septum was targeted with fluoroscopic guidance with contrast injection. We divided patients into two groups based on the implantation site confirmed by CT: septal and non-septal, which included the anterior/posterior edge of the septum and free wall. We compared the complication rates and pacemaker parameters between the two groups. RESULTS: A total of 67 patients underwent CT after the procedure; among them, 28 were included in the septal group and 39 were included in the non-septal group. The non-septal group had significantly higher R wave amplitudes (6.5 ± 3.3 vs. 9.7 ± 3.9 mV, p = .001), lower pacing threshold (1.0 ± 0.94 vs. 0.63 ± 0.45 V/0.24 ms, p = .02), and higher pacing impedance (615 ± 114.1 vs. 712.8 ± 181.3 ohms, p = .014) after the procedure compared to the septal group. Cardiac injuries were observed in four patients (one cardiac tamponade, one possible apical hematoma, two asymptomatic pericardial effusion), which were only observed in the non-septal group. CONCLUSIONS: Leadless pacemaker implantation may be technically challenging with substantial number of patients with non-septal implantation when assessed by CT. Septal implantation may have a lower risk of cardiac injury but may lead to inferior pacemaker parameters than non-septal implantation.

Risk factors for venous bleeding complication at the femoral puncture site after catheter ablation of atrial fibrillation.

BACKGROUND: Venous bleeding complication is often observed after catheter ablation of atrial fibrillation (AF), but the risk factors remain unclear. METHODS: We retrospectively evaluated 570 consecutive patients who underwent catheter ablation of AF from April 2012 to March 2017. After the procedure, the sheaths were removed, and hemostasis was obtained by manual compression followed by application of rolled gauze with elastic bandage and continuous pressure to the puncture site. We evaluated the risk factors for venous bleeding complications defined as hemorrhage from the puncture site that needed recompression after removal of the elastic bandage and rolled gauze. RESULTS: After excluding 11 patients because of missing data, 559 patients (395 [70.7%] men, mean age: 65.6 ± 8.7 years) were included for analysis. Venous bleeding complication was observed in 213 patients (38.1%). In the multivariate logistic regression analysis, low body mass index (BMI; odds ratio [OR] 0.95, 95% CI 0.90-1.00, P = .04), short compression time (OR 0.77, 95% CI 0.68-0.88, P < .001), and antiplatelet therapy (OR 1.86, 95% CI 1.09-3.16, P = .02) were independent risk factors for venous bleeding complication. CONCLUSIONS: Low BMI, short compression time, and antiplatelet therapy were independent risk factors for venous bleeding complication after catheter ablation of AF. Longer compression time may be needed for patients with low BMI and/or those receiving antiplatelet therapy.