Diagnostic performance of an acoustic-based system for coronary artery disease risk stratification

ObjectiveDiagnosing coronary artery disease (CAD) continues to require substantial healthcare resources. Acoustic analysis of transcutaneous heart sounds of cardiac movement and intracoronary turbulence due to obstructive coronary disease could potentially change this. The aim of this study was thus to test the diagnostic accuracy of a new portable acoustic device for detection of CAD.MethodsWe included 1675 patients consecutively with low to intermediate likelihood of CAD who had been referred for cardiac CT angiography. If significant obstruction was suspected in any coronary segment, patients were referred to invasive angiography and fractional flow reserve (FFR) assessment. Heart sound analysis was performed in all patients. A predefined acoustic CAD-score algorithm was evaluated; subsequently, we developed and validated an updated CAD-score algorithm that included both acoustic features and clinical risk factors. Low risk is indicated by a CAD-score value ≤20.ResultsHaemodynamically significant CAD assessed from FFR was present in 145 (10.0%) patients. In the entire cohort, the predefined CAD-score had a sensitivity of 63% and a specificity of 44%. In total, 50% had an updated CAD-score value ≤20. At this cut-off, sensitivity was 81% (95% CI 73% to 87%), specificity 53% (95% CI 50% to 56%), positive predictive value 16% (95% CI 13% to 18%) and negative predictive value 96% (95% CI 95% to 98%) for diagnosing haemodynamically significant CAD.ConclusionSound-based detection of CAD enables risk stratification superior to clinical risk scores. With a negative predictive value of 96%, this new acoustic rule-out system could potentially supplement clinical assessment to guide decisions on the need for further diagnostic investigation.Trial registration numberClinicalTrials.gov identifier NCT02264717; Results.</jats:sec

Effect of Guiding Catheter Extubation During Physiological Assesment of Stenosis

BACKGROUND: Extubation of the coronary guiding catheter may affect flow and pressure measurements in the coronary vessel during invasive coronary angiography (ICA).AIM: This study aims to investigate the impact of guiding catheter extubation on fractional flow reserve (FFR), coronary flow reserve (CFR), and the index of microcirculatory resistance (IMR).METHODS: This predefined subgroup analysis of the Dan-NICAD 2 study included patients with chronic coronary syndrome referred to ICA based on a coronary computed tomography angiography. Thermodilution was performed in all vessels evaluated with 30%-90% diameter stenosis on a visual estimate. The primary endpoints were FFR, CFR, and IMR changes when the guiding catheter was extubated from the coronary ostium. Three-dimensional quantitative coronary angiography analysis was conducted to evaluate whether the proximal flow area, defined as the area of the guiding catheter subtracted from the area of the vessel ostium, correlated with the changes in FFR, CFR, and IMR.RESULTS: In 84 patients, coronary physiological measurements were performed twice: once with the guiding catheter intubated and once extubated. FFR decreased during guiding catheter extubation (0.82 ± 0.09 vs. 0.80 ± 0.10) with a mean difference of 0.02, 95% CI [0.01-0.03], p &lt; 0.001. Following extubation, eight patients (8.7%) showed FFR values shifting from &gt; 0.80 to ≤ 0.80. IMR increased during guiding catheter extubation (16.8 ± 8.50 vs. 21.4 ± 16.1) with mean difference of 4.67 [95% CI 1.74-7.60], p = 0.002. No significant changes in CFR were observed; intubated 3.09 ± 1.31 vs 2.84 ± 1.30; difference mean 0.25, [95% CI -0.07 to 0.56], p = 0.12. No significant correlations were found between the proximal flow area and the difference in FFR, CFR, and IMR from intubated to extubated: (r -0.14, p = 0.23), (r -0.11, p = 0.34), and (r -0.16, p = 0.17), respectively.CONCLUSION: Extubating the guiding catheter decreased FFR and increased IMR. This resulted in an FFR decrease from &gt; 0.80 to ≤ 0.80 in 8.7% of patients. CFR remained unchanged. No significant correlation was found between FFR/IMR changes and proximal flow area.</p