Background:This study evaluated the diagnostic capability of on-site coronary computed tomography-derived computational fractional flow reserve (CT-FFR) determinations for detecting coronary artery ...disease (CAD), as assessed by invasive fractional flow reserve (FFR).Methods and Results:Seventy-four patients with coronary artery calcium scores <1,500 who underwent coronary CT angiography (CTA) and invasive FFR measurements within 90 days were retrospectively reviewed. CT-FFR was computed using a prototype machine-learning (ML) algorithm in 91 vessels; 47 vessels of 42 patients were determined to have significant CAD (FFR ≤0.8). Correlation between CT-FFR and FFR was good (r=0.786, P<0.001). Per-vessel area under the curve was significantly larger for CT-FFR (0.907, 95% confidence interval: 0.828–0.958) than for CTA stenosis ≥50% (0.595, 0.487–0.697) or ≥70% (0.603, 0.495–0.705) (both P<0.001). Standard coronary CTA classifications recommended further functional tests in 57 patients with moderate or worse stenosis on CTA. CT-FFR analysis (mean analysis time: 16.4±7.5 min) corrected the standard coronary CTA classification in 18 of 74 patients and confirmed it in 45 of 74 patients. Thus, the per-patient diagnostic accuracy of the classifications was improved from 66% (54–77%) to 85% (75–92%).Conclusions:On-site CT-FFR based on a ML algorithm can provide good diagnostic performance for detecting hemodynamically significant CAD, suggesting the high value of coronary CTA for selected patients in clinical practice.
Background:Fractional flow reserve (FFR) is widely used for the assessment of myocardial ischemia. Intravascular ultrasound (IVUS) is an intracoronary imaging method that provides information about ...lumen and vessel morphology. Previous studies on the expanded use of IVUS to identify functional ischemia have noted an association between anatomy and physiology, but IVUS-derived minimum lumen area (MLA) has a weak-moderate correlation with myocardial ischemia compared with FFR. We developed a method to calculate FFR using IVUS-derived anatomical information for the assessment of myocardial ischemia. The aims of this study were to investigate the relationship between wire-based FFR and IVUS-derived FFR (IVUS-FFR) and to compare the usefulness of IVUS-FFR and IVUS-derived MLA for functional assessment.Methods and Results:We retrospectively analyzed 50 lesions in 48 patients with coronary stenosis who underwent IVUS and FFR simultaneously. IVUS-FFR was calculated using our original algorithm and fluid dynamics. Mean percent diameter stenosis determined on quantitative coronary angiography and on FFR was 56.4±10.7 and 0.69±0.08, respectively. IVUS-FFR had a stronger linear correlation with FFR (R=0.78, P<0.001; root mean square error, 0.057 FFR units) than with IVUS-derived MLA (R=0.43, P=0.002).Conclusions:IVUS-FFR may be a more valuable method to identify myocardial ischemia, compared with IVUS-derived MLA.
Objective Coronary plaques with low attenuation on computed tomography (CT) angiography may indicate vulnerable plaques. However, plaque CT attenuation is reported to be significantly affected by ...intracoronary attenuation. Recently, the diluted-contrast injection protocol was established to facilitate more uniform intracoronary attenuation than can be achieved with the generally used body-weight-adjusted protocol. We validated the relationship between low-attenuation plaque on CT and lipid-rich plaque using integrated backscatter-intravascular ultrasound (IB-IVUS) as the standard reference. Methods Plaques were divided into tertiles (T1, T2, and T3) according to the plaque CT attenuation, calculated as the average of five intra-plaque regions of interest, and compared with the plaque characteristics noted on IB-IVUS. Patients Patients who underwent both CT angiography using a diluted-contrast injection protocol and IB-IVUS were retrospectively analyzed. Results Thirty-nine plaques in 32 patients were analyzed by CT angiography and IB-IVUS. The median plaque CT attenuation (Hounsfield units) of each tertile was 30 (T1), 48 (T2), and 68 (T3). Although no significant difference was noted in conventional quantitative IVUS parameters (e.g. plaque burden), the T1 with lowest plaque CT attenuation had the highest percentage lipid area by IB-IVUS 75.1% (T1), 57.8% (T2), and 50.8% (T3), respectively, p<0.01. Furthermore, the plaque CT attenuation had a significant negative correlation with the percentage lipid area (r=-0.59, p<0.01). Conclusion CT angiography-based plaque characterization using a diluted-contrast injection protocol may aid in the quantitative detection of lipid-rich plaque.
We investigated the independent and incremental role of worsening arterial stiffness in new-onset heart failure (HF) in patients with preclinical HF. We retrospectively studied 456 consecutive ...asymptomatic patients with HF risk factors (hypertension, obesity, type 2 diabetes mellitus, atrial fibrillation and ischemic heart disease) who underwent paired applanation tonometry examinations (median interval of 2.4 years) during 2006-2011. Brachial ankle pulse wave velocity (baPWV) was measured as a surrogate marker of arterial stiffness. Patients were followed up for admission for new-onset HF over a median duration of 4.9 years after the second examination. HF was observed in 30 patients (7%). The change in baPWV (∆baPWV) was significantly associated with hospitalization for new-onset HF, independent of and incremental to comorbidities, renal dysfunction, left ventricular (LV) dysfunction and baPWV at baseline. Even in patients with an LV ejection fraction of ⩾40%, ∆baPWV was significantly associated with hospitalization for new-onset HF after similar adjustments. When the patients were divided into groups based on this cutoff value of ⩾15% ∆baPWV and the generally accepted external cutoff value of ⩾1750 cm s
for baseline baPWV, the Kaplan-Meier estimates of the time of hospitalization for new-onset HF showed that a higher rate of HF was associated with higher baPWV at baseline and higher ∆baPWV (P=0.00005). In asymptomatic patients with cardiovascular risk factors, the deterioration in arterial stiffness was associated with hospitalization for new-onset HF, independent of and incremental with the clinical LV function and increased stiffness parameters at baseline.
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