Impact of vessel morphology on CT-derived fractional-flow-reserve in non-obstructive coronary artery disease in right coronary artery.

OBJECTIVES: Computed tomography (CT)-derived fractional flow reserve (FFRCT) decreases continuously from proximal to distal segments of the vessel due to the influence of various factors even in non-obstructive coronary artery disease (NOCAD). It is known that FFRCT is dependent on vessel-length, but the relationship with other vessel morphologies remains to be explained. PURPOSE: To investigate morphological aspects of the vessels that influence FFRCT in NOCAD in the right coronary artery (RCA). METHODS: A total of 443 patients who underwent both FFRCT and invasive coronary angiography, with < 50% RCA stenosis, were evaluated. Enrolled RCA vessels were classified into two groups according to distal FFRCT: FFRCT ≤ 0.80 (n = 60) and FFRCT > 0.80 (n = 383). Vessel morphology (vessel length, lumen diameter, lumen volume, and plaque volume) and left-ventricular mass were assessed. The ratio of lumen volume and vessel length was defined as V/L ratio. RESULTS: Whereas vessel-length was almost the same between FFRCT ≤ 0.80 and > 0.80, lumen volume and V/L ratio were significantly lower in FFRCT ≤ 0.80. Distal FFRCT correlated with plaque-related parameters (low-attenuation plaque, intermediate-attenuation plaque, and calcified plaque) and vessel-related parameters (proximal and distal vessel diameter, vessel length, lumen volume, and V/L ratio). Among all vessel-related parameters, V/L ratio showed the highest correlation with distal FFRCT (r = 0.61, p < 0.0001). Multivariable analysis showed that calcified plaque volume was the strongest predictor of distal FFRCT, followed by V/L ratio (ß-coefficient = 0.48, p = 0.03). V/L ratio was the strongest predictor of a distal FFRCT ≤ 0.80 (cut-off 8.1 mm3/mm, AUC 0.88, sensitivity 90.0%, specificity 76.7%, 95% CI 0.84-0.93, p < 0.0001). CONCLUSIONS: Our study suggests that V/L ratio can be a measure to predict subclinical coronary perfusion disturbance. CLINICAL RELEVANCE STATEMENT: A novel marker of the ratio of lumen volume to vessel length (V/L ratio) is the strongest predictor of a distal CT-derived fractional flow reserve (FFRCT) and may have the potential to improve the diagnostic accuracy of FFRCT. KEY POINTS: • Physiological FFRCT decline depends not only on vessel length but also on the lumen volume in non-obstructive coronary artery disease in the right coronary artery. • FFRCT correlates with plaque-related parameters (low-attenuation plaque, intermediate-attenuation plaque, and calcified plaque) and vessel-related parameters (proximal and distal vessel diameter, vessel length, lumen volume, and V/L ratio). • Of vessel-related parameters, V/L ratio is the strongest predictor of a distal FFRCT and an optimal cut-off value of 8.1 mm3/mm.

Clinical and prognostic incremental value of FFRCT in screening of patients with obstructive coronary artery disease.

BACKGROUND: Coronary computed tomography angiography (CCTA) -derived fractional flow reserve (FFRCT) is recommended to evaluate the functional consequences of obstructive coronary artery disease (OCAD). Real-world incremental impacts of FFRCT use still remains under debate. METHODS: 1601 patients with suspected OCAD on CCTA (>50 â€‹% stenosis), including 808 (50.5 â€‹%) patients evaluated by FFRCT, were included from a 2013-2021 registry. Propensity adjusted impacts of FFRCT use on rates of invasive coronary angiography (ICA), myocardial revascularization (MR) and post MR major adverse cardiac events (MACE) were reported, including a sensitivity analysis in severe OCAD (>70 â€‹% stenosis) (n â€‹= â€‹450). Accuracy of numerical and comprehensive FFRCT interpretations in selection of patients requiring a MR were also compared. RESULTS: 1160 (72,5 â€‹%) ICA, 559 (34.9 â€‹%) MR and 137 (24.5 â€‹%) post MR MACE occurred at 4.7 â€‹± â€‹1.9 years. FFRCT use was independently associated with decreased rate of ICA and MR (OR: 0.66; 95 â€‹% CI 0.53-0.83, p â€‹< â€‹0.001 and OR: 0.71; 95 â€‹% CI 0.58-0.88, p â€‹< â€‹0.01, respectively). Compared to the numerical interpretation, the FFRCT comprehensive assessment increased the ratio of MR per ICA (61.7 â€‹% vs 50.1 â€‹%, p â€‹< â€‹0.01) and was more accurate in selection of patients requiring MR. FFRCT reduced post MR MACE (OR: 0.64; 95 â€‹% CI 0.43-0.96, p â€‹< â€‹0.05). All these associations were no longer observed in severe OCAD. CONCLUSION: Implementing FFRCT in OCAD patients reduces ICA use, improves selection of patients requiring MR and reduces post MR MACE. However, these incremental values of FFRCT were no longer observed in severe OCAD.

Coronary artery disease in atrial fibrillation ablation: impact on arrhythmic outcomes.

AIMS: Catheter ablation (CA) is an established treatment for atrial fibrillation (AF). A computed tomography (CT) may be performed before ablation to evaluate the anatomy of pulmonary veins. The aim of this study is to investigate the prevalence of patients with coronary artery disease (CAD) detected by cardiac CT scan pre-ablation and to evaluate the impact of CAD and revascularization on outcomes after AF ablation. METHODS AND RESULTS: All consecutive patients with AF diagnosis, hospitalized at Universitair Ziekenhuis Brussel, Belgium, between 2015 and 2019, were prospectively screened for enrolment in the study. Inclusion criteria were (i) AF diagnosis, (ii) first procedure of AF ablation with cryoballoon CA, and (iii) contrast CT scan performed pre-ablation. A total of 576 consecutive patients were prospectively included and analysed in this study. At CT scan, 122 patients (21.2%) were diagnosed with CAD, of whom 41 patients (7.1%) with critical CAD. At survival analysis, critical CAD at CT scan was a predictor of atrial tachyarrhythmia (AT) recurrence during the follow-up, only in Cox univariate analysis [hazard ratio (HR) = 1.79] but was not an independent predictor in Cox multivariate analysis. At Cox multivariate analysis, independent predictors of AT recurrence were as follows: persistent AF (HR = 2.93) and left atrium volume index (HR = 1.04). CONCLUSION: In patients undergoing CT scan before AF ablation, critical CAD was diagnosed in 7.1% of patients. Coronary artery disease and revascularization were not independent predictors of recurrence; thus, in this patient population, AF ablation should not be denied and can be performed together with CAD treatment.

Pulmonary Vein Remodeling Between Atrial Fibrillation Subtypes: A Matched Comparison Cardiac Computed Tomography-Based Study Between Patients With Paroxysmal and Persistent Atrial Fibrillation.

Although pulmonary vein (PV) isolation (PVI) is the cornerstone for atrial fibrillation (AF) ablation, no data exist comparing PV anatomy between AF subtypes directly. We aimed to compare PV anatomic characteristics between paroxysmal (PAF) and persistent AF (PeAF) in a matched population using cardiac computed tomography (CCT). Fifty-eight PeAF patients (with CCT prior first AF ablation procedure, absence of valvular disease/previous cardiac intervention), and 58 age-, sex-, body surface area-matched PAF patients were evaluated for left atrial (LA) and PV anatomy: ostial area, ovality index (OVI), transverse/frontal angles. In PeAF vs PAF group, beside higher LA volume index (LAVI), PVs' ostial areas were significantly larger (between 64 - 101 mm2, P < 0.001 for all PVs; remaining valid after LAVI adjustment for left superior [LS], left inferior [LI], and right inferior [RI]PV); left PVs were less oval (0.7 - 0.11 OVI decrease, P =0.039 for LSPV; P = 0.012 for LIPV); LSPV (P = 0.019), LIPV (P < 0.001), RIPV (P = 0.029) were more posteriorly directed; whereas LSPV (P = 0.002), and right superior PV (P = 0.043) were more superiorly directed. Incidence of anatomic variations or early branching was not different. This study showed significant anatomical PV differences between patients with PeAF and PAF, in terms of PV orientation, ostial size and ovality. Anticipating such anatomical differences may aid in choosing the adequate catheter design and technology for PeAF ablation.

Impact of ramus coronary artery on computed tomography derived fractional flow reserve (FFRCT ) in no apparent coronary artery disease.

BACKGROUND: The ramus artery contributes to the development of turbulence, which may influence computed tomography (CT) derived fractional flow reserve (FFRCT ) even without coronary artery disease (CAD). The relationship between ramus-induced turbulence and FFRCT is unclear. METHOD AND RESULTS: A total of 120 patients with <20% coronary stenosis assessed by both FFRCT and invasive coronary angiography were evaluated. The patients were divided into three groups: absent-ramus (n = 72), small-ramus that could not be analyzed by FFRCT (n = 18), and large-ramus that could be analyzed by FFRCT (n = 30). FFRCT measurements were performed at the proximal and distal segments of the left anterior descending (LAD), left circumflex (LCX), and ramus artery. With absent-ramus and small-absent ramus groups, FFRCT was measured at the distal end of the left main trunk at the same level for the proximal segments of the LAD and LCX. In absent-ramus group, proximal FFRCT showed no significant differences between three vessels (LAD = .96 ± .02; MID = .97 ± .02; LCX = .97 ± .02). However, in small and large-ramus groups, proximal FFRCT was significantly higher in the ramus artery than LAD and LCX (small-ramus, LAD = .95 ± .03, Ramus = .97 ± .02, LCX = .95 ± .03; large-ramus: LAD = .95 ± .03, Ramus = .98 ± .01; LCX = .96 ± .03; p < .05). A large ramus was associated with a higher prevalence of a distal FFRCT ≤.80 (odds ratio 7.0, 95% CI 1.2-40.1, p = .03). A proximal ramus diameter predicted distal FFRCT ≤.80 (cut-off 2.1 mm, AUC .76, sensitivity 100%, specificity 52%, 95% CI .61-.90). CONCLUSIONS: The presence of a large-ramus artery may cause an FFRCT decline in no apparent CAD.

Evaluation of coronary artery disease in patients undergoing atrial fibrillation ablation: a non-invasive FFR computed tomography study.

To evaluate coronary artery disease (CAD) with computed tomography coronary angiography (CTCA)-derived fractional flow reserve (FFR) in patients with atrial fibrillation (AF) requiring ablation. The study population consisted of 151 patients who underwent CTCA before AF ablation (AF group), and a control group of 151 patients from the outpatient clinic who underwent CTCA without any history of AF (non-AF group), matched for age, sex, BMI, and angina symptomatology. All study patients underwent CTCA with subdivision of coronary lesion type into severe (≥ 70% luminal narrowing), moderate (50% ≤ luminal narrowing < 70%), and mild stenosis (< 50% luminal narrowing). In patients with ≥ 1 moderate or severe stenosis, non-invasive FFR was calculated from CTCA (FFRCT). Baseline characteristics and CAD risk factors were similar between the 2 groups. During CTCA, 38% of the patients in the AF group were in ongoing atrial arrhythmia (either AF or regular atrial tachycardia). The number of patients with severe (10 (6.6%) vs 10 (6.6%), P = 1.00), moderate (14 (9.5%) vs 10 (6.7%), P = 0.4), and mild stenosis (43 (28.5%) vs 56 (37.1%), P = 0.11) was not significantly different between the 2 groups. Performance of FFRCT was feasible in 32/44 patients (73%), and failed in 27% of the patients (7 and 5 patients in the AF and non-AF group, respectively, P = 0.74). No difference was observed in the prevalence of hemodynamically significant stenosis (FFRCT ≤ 0.80) (15 (9.9%) vs 12 (7.9%), P = 0.85). Our study showed technical feasibility of CTCA in all patients of both groups, including the patients with AF as presenting rhythm. The FFRCT add-on analysis failed equally frequent in patients of the AF versus non-AF group. An equal rate of CAD was observed in the AF group and non-AF group, favoring the concept of shared associated risk factors for CAD and AF.

Impact of coronary bifurcation angle on computed tomography derived fractional flow reserve in coronary vessels with no apparent coronary artery disease.

OBJECTIVES: Computed tomography (CT) derived fractional flow reserve (FFRCT) decreases from the proximal to the distal part due to a variety of factors. The energy loss due to the bifurcation angle may potentially contribute to a progressive decline in FFRCT. However, the association of the bifurcation angle with FFRCT is still not entirely understood. This study aimed to investigate the impact of various bifurcation angles on FFRCT decline below the clinically crucial relevance of 0.80 in vessels with no apparent coronary artery disease (CAD). METHODS: A total of 83 patients who underwent both CT angiography including FFRCT and invasive coronary angiography, exhibiting no apparent CAD were evaluated. ΔFFRCT was defined as the change in FFRCT from the proximal to the distal in the left anterior descending artery (LAD) and left circumflex artery (LCX). The bifurcation angle was calculated from three-dimensional volume rendered images. Vessel morphology and plaque characteristics were also assessed. RESULTS: ΔFFRCT significantly correlated with the bifurcation angle (LAD angle, r = 0.35, p = 0.001; LCX angle, r = 0.26, p = 0.02) and vessel length (LAD angle, r = 0.30, p = 0.005; LCX angle, r = 0.49, p < 0.0001). In LAD, vessel length was the strongest predictor for distal FFRCT of ≤ 0.80 (ß-coefficient = 0.55, p = 0.0003), immediately followed by the bifurcation angle (ß-coefficient = 0.24, p = 0.02). The bifurcation angle was a good predictor for a distal FFRCT ≤ 0.80 (LAD angle, cut-off 31.0°, AUC 0.70, sensitivity 74%, specificity 68%; LCX angle, cut-off 52.6°, AUC 0.86, sensitivity 88%, specificity 85%). CONCLUSIONS: In vessels with no apparent CAD, vessel length was the most influential factor on FFRCT, directly followed by the bifurcation angle. KEY POINTS: • Both LAD and LCX bifurcation angles are factors influencing FFR CT. • Bifurcation angle is one of the predictors of a distal FFRCT of ≤ 0.80 and an optimal cut-off value of 31.0° for the LAD and 52.6° for the LCX. • Bifurcation angle should be taken into consideration when interpreting numerical values of FFRCT.

Predictors of late pulmonary vein reconnection in patients with arrhythmia recurrence after cryoballoon ablation-per vein analysis including cardiac computed tomography-based anatomic factors.

AIMS: To identify predictors of individual late pulmonary vein (PV) reconnection after second-generation cryoballoon (CB2) ablation. Anatomic indicators of late pulmonary vein reconnection (LPVR) post-CB2 ablation have not yet been studied on an individual PV level, nor weighed against clinical and procedural factors. METHODS AND RESULTS: Clinical, procedural, and PV anatomic data from 125 patients with a repeat procedure for arrhythmia recurrence after index CB2 ablation were analyzed. Preprocedural computed tomography (CT) evaluated 486 PVs for measurement of size; shape (ovality index); carina width; and orientation angle in frontal (superior/inferior) and transversal (anterior/posterior) plane (with horizontal line 0° as reference and upper/lower half circle as positive/negative value, respectively). Durable isolation in all PVs was demonstrated in 50/125 (40%) patients. Late reconnection rates at the different PVs were as follows: 16% left superior (LS), 12% left inferior (LI), 17% right superior (RS), and 31% right inferior (RI) PV. Multivariable analysis performed per vein showed following independent determinants predicting LPVR: ovality index [odds ratio (OR) 1.61, 95% confidence interval (CI) 1.07-2.41, P = 0.022] and carina width (OR 0.75, CI 0.59-0.96, P = 0.024) for LSPV; carina width (OR 0.71, CI 0.53-0.95, P = 0.020) for LIPV; frontal angle (OR 0.91, CI 0.87-0.95, P < 0.001) for RIPV; and transversal angle (OR 1.15, CI 1.03-1.31, P = 0.032) for RSPV. CONCLUSION: Cardiac CT-based evaluation of anatomic PV characteristics presented higher predictive value compared to clinical and procedural variables for individual LPVR after CB2 ablation. Pre-procedural identification of unfavourable PV anatomy might be important to tailor the ablation approach.

A patient- and acquisition-tailored injection approach for improving consistency of CT enhancement towards a target CT value in coronary CT angiography.

BACKGROUND: Unoptimized coronary CT angiography (CTA) exams typically result in a highly variable arterial enhancement (HUa ) across patients. This study aimed at harmonizing arterial enhancement by implementing a patient-, contrast- and kV-tailored injection protocol. METHODS: First, the optimal body size metric to predict HUa was identified by retrospectively analysing images of 76 patients, acquired with 70 ml contrast media (G1). Second, using phantom experiments, correction factors for the effect of kV and contrast concentration on HUa were determined. Third, a model was developed, prescribing the optimal contrast dose to be injected to obtain a diagnostically appropriate arterial target enhancement HUtarget . The model was then validated on 278 prospectively collected patients, in two groups with two different HUtarget : 525 HU (207 patients, G2A) and 425 HU (71 patients, G2B). The HUa histograms were compared among groups and to the target enhancement through their mean and standard deviation (SD) at 100 kVp reference level. Also, signal-to-noise ratio was obtained and compared among the groups. RESULTS: Fat free mass (FFM) showed the highest correlation with HUa (r = 0.69). KVp correction factors ranged from 0.65 at 70 kVp to 1.22 at 140 kVp. The obtained model reduced the group heterogeneity (SD) from 101HU for reference G1 to 75HU (p < 0.001) for G2A and 68HU (p < 0.001) for G2B. The mean HUa of 506HU in G2A was slightly below HUtarget  = 525HU (p = 0.01) whereas in G2B, the mean HUa of 414HU was not significantly different from HUtarget  = 425HU (p = 0.54). The total iodine dose was lowered from 19.5 g-I to 17.6 g-I and 14.2 g-I from G1 to G2A and G2B, on average. CONCLUSION: A contrast injection model, based on patient's fat free mass and accounting for the contrast agent concentration and the planned CT-scan tube voltage, harmonized arterial enhancement among patients towards a predefined target enhancement in coronary CTA scanning, without affecting the bolus timing.

Subclinical Myocardial Dysfunction in Patients with Persistent Dyspnea One Year after COVID-19-Why Should Screening for Cardiovascular Diseases Be Performed? Reply to Vankrunkelsven, P. Tendentious Paper-Titles and Wrong Conclusions Lead to Fear in the Population and Medical Overconsumption. Comment on "Luchian et al. Subclinical Myocardial Dysfunction in Patients with Persistent Dyspnea One Year after COVID-19. Diagnostics 2022, 12, 57".

We have read with interest the comment by Vankrunkelsven P. [...].