Comparison between the diagnostic performance of vessel fractional flow reserve and nonhyperemic pressure ratio for functionally significant coronary stenosis severity as assessed by fractional flow reserve.

BACKGROUND: Fractional flow reserve (FFR) and nonhyperemic pressure ratios (NHPRs) have been widely used to assess the functional severity of coronary stenosis. However, their measurement requires using a pressure wire, making their use in all patients difficult. The recently developed vessel fractional flow reserve (vFFR), derived from three-dimensional quantitative coronary angiography, is expected to serve as a surrogate for pressure wire assessment. METHODS: This retrospective study was conducted on patients with intermediate coronary stenosis who underwent FFR and NHPR measurements. The vFFR and NHPR values were compared for diagnosing coronary stenosis as defined by an FFR of ≤0.80, and the number of patients not requiring wire-based assessment was estimated. RESULTS: In a total of 90 lesions from 74 patients (median [SD] age 75 [12] years; men 80%), the median FFR was 0.78 (0.72-0.84), and 57% of these lesions (N = 51) exhibited an FFR of ≤0.80. vFFR provided high discrimination for coronary stenosis (area under the curve 0.80, 95% confidence interval 0.70-0.90), which was comparable to that of NHPRs (p = 0.42). High diagnostic accuracy was consistently observed across a variety of clinical presentations (i.e., old age, diabetes, target coronary artery, and left ventricular hypertrophy) (pinteraction > 0.05). In total, 55 lesions (61%) demonstrated positive or negative likelihood of coronary stenosis when vFFR was <0.73 (specificity 90%) or >0.87 (sensitivity 88%), respectively. CONCLUSION: vFFR demonstrated excellent diagnostic performance for detecting functionally significant coronary stenosis as evaluated by FFR. vFFR may be used as a surrogate for pressure wire assessment.

Artificial intelligence-derived left ventricular strain in echocardiography in patients treated with chemotherapy.

Global longitudinal strain (GLS) is an echocardiographic measure to detect chemotherapy-related cardiovascular dysfunction. However, its limited availability and the needed expertise may restrict its generalization. Artificial intelligence (AI)-based GLS might overcome these challenges. Our aims are to explore the agreements between AI-based GLS and conventional GLS, and to assess whether the agreements were influenced by expertise levels, cardiac remodeling and cardiovascular diseases/risks. Echocardiographic images in the apical four-chamber view of left ventricle were retrospectively analyzed based on AI-based GLS in patients treated with chemotherapy, and correlation between AI-based GLS (Caas Qardia, Pie Medical Imaging) and conventional GLS (Vivid E9/VividE95, GE Healthcare) were assessed. The agreement between unexperienced physicians ("GLS beginner") and experienced echocardiographer were also assessed. Among 94 patients (mean age 69 ± 12 years, 73% female), mean left ventricular ejection fraction was 64 ± 6%, 14% of patients had left ventricular hypertrophy, and 21% had left atrial enlargement. Mean GLS was - 15.9 ± 3.4% and - 19.0 ± 3.7% for the AI and conventional method, respectively. There was a moderate correlation between these methods (rho = 0.74; p < 0.01), and bias was - 3.1% (95% limits of agreement: -8.1 to 2.0). The reproducibility between GLS beginner and an experienced echocardiographer was numerically better in the AI method than the conventional method (inter-observer agreement = 0.82 vs. 0.68). The agreements were consistent across abnormal cardiac structure and function categories (p-for-interaction > 0.10). In patients treated with chemotherapy. AI-based GLS was moderately correlated with conventional GLS and provided a numerically better reproducibility compared with conventional GLS, regardless of different levels of expertise.

Diagnostic performance of pressure-bounded coronary flow reserve.

Fluid dynamics studies have proposed that coronary flow reserve can be calculated from coronary artery pressure instead of coronary blood flow. We sought to investigate the diagnostic performance of pressure-bounded coronary flow reserve (pb-CFR) compared with CFR measured by conventional thermodilution method (CFRthermo) in the clinical setting. Pressure guidewire was used to measure CFRthermo and fractional flow reserve (FFR) in left anterior descending coronary artery in 62 patients with stable coronary artery disease. Pb-CFR was calculated only with resting distal coronary artery pressure (Pd), resting aortic pressure (Pa) and FFR. Pb-CFR was moderately correlated with CFRthermo (r = 0.54, P < 0.001). Pb-CFR showed a poor agreement with CFRthermo, presenting large values of mean difference and root mean square deviation (1.5 ± 1.4). Pb-CFR < 2.0 predicted CFRthermo < 2.0 with an accuracy of 79%, sensitivity of 83%, specificity of 78%, positive predictive value of 48%, negative predictive value of 95%. The discordance presenting CFRthermo < 2.0 and pb-CFR ≥ 2.0 was associated with diffuse disease (P < 0.001). The discordance presenting CFRthermo ≥ 2 and pb-CFR < 2 was associated with a high FFR (P = 0.002). Pb-CFR showed moderate correlation and poor agreement with CFRthermo. Pb-CFR might be reliable in excluding epicardial coronary artery disease and microcirculatory disorders.