Diagnostic performance of computational fluid dynamics (CFD)-based fractional flow reserve (FFR) derived from coronary computed tomographic angiography (CCTA) for assessing functional severity of coronary lesions.

Background: Fractional flow reserve (FFR) is the gatekeeper for lesion-specific revascularization decision-making in patients with stable coronary artery disease (CAD). The potential of noninvasive calculation of FFR from coronary computed tomographic angiography (CCTA) to identify ischemia-causing lesions has not been sufficiently assessed. The objective of this study was to evaluate the feasibility and diagnostic accuracy of a novel computational fluid dynamics (CFD)-based technology, termed as AccuFFRct, for the diagnosis of functionally significant lesions from CCTA, using wire-based FFR as a reference standard. Methods: A total of 191 consecutive patients who underwent CCTA and FFR measurement for suspected or known CAD were retrospectively enrolled at 2 medical centers. Three-dimensional anatomic model of coronary tree was extracted from CCTA data, CFD was applied subsequently with a novel strategy for the computation of FFR in a blinded fashion by professionals. Results were compared to invasive FFR, a threshold of ≤0.80 was used to indicate the hemodynamically relevant stenosis. Results: On a per-patient basis, the overall accuracy, sensitivity, specificity of AccuFFRct for detecting ischemia were 91.78% (95% CI: 86.08% to 95.68%), 92.31% (95% CI: 81.46% to 97.86%) and 91.49% (95% CI: 83.92% to 96.25%), respectively; those for per-vessel basis were 91.05% (95% CI: 86.06% to 94.70%), 92.73% (95% CI: 82.41% to 97.98%) and 90.37% (95% CI: 84.10% to 94.77%), respectively. The AccuFFRct and FFR was well correlated on per-patient (r=0.709, P<0.001) and per-vessel basis (r=0.655, P<0.001). The AUC of AccuFFRct determination was 0.935 (95% CI: 0.881 to 0.969) and 0.927 (95% CI: 0.880 to 0.960) on per-patient and per-vessel basis. Conclusions: This novel CFD-based CCTA-derived FFR shows good diagnostic performance for detecting hemodynamic significance of coronary stenoses and may potentially become a new gatekeeper for invasive coronary angiography (ICA).

Functional Assessment of Coronary Artery Stenosis from Coronary Angiography and Computed Tomography: Angio-FFR vs. CT-FFR.

This study was designed to compare the diagnostic performance of angio-FFR and CT-FFR for detecting hemodynamically significant coronary stenosis. Angio-FFR and CT-FFR were measured in 110 patients (139 vessels) with stable coronary disease using invasive FFR as the reference standard. On per-patient basis, angio-FFR was highly correlated with FFR (r =0.78, p <0.001), while the correlation was moderate between CT-FFR and FFR (r =0.68, p <0.001). Diagnostic accuracy, sensitivity, and specificity for angio-FFR were 94.6%, 91.4%, and 96.0%, respectively; and those of CT-FFR were 91.8%, 91.4%, and 92%, respectively. Bland-Altman analysis showed that angio-FFR had a larger average difference and a smaller root mean squared deviation than CT-FFR compared with FFR (-0.014±0.056 vs. 0.0003±0.072). Angio-FFR had a slightly higher AUC than that of CT-FFR (0.946 vs. 0.935, p =0.750). Angio-FFR and CT-FFR computed from coronary images could be accurate and efficient computational tools for detecting lesion-specific ischemia of coronary artery stenosis. Angio-FFR and CT-FFR calculated based on the two types of images can both accurately diagnose functional ischemia of coronary stenosis. CT-FFR can act as a gatekeeper to the catheter room, assisting doctors in determining whether patients need to be screened by coronary angiography. Angio-FFR can be used in the catheter room to determine the functional significant stenosis for helping decision-making in revascularization.

[Cardiopulmonary exercise test accurately prognoses risk of postoperative complications in patients undergoing lung resection in good functional status].

Objective: To explore the value of predicting accurately the risk of complications after thoracoscopic lung resection by preoperative CPET index. Methods: Selected 448 patients who completed CPET with static pulmonary function test (PFT) before operation, followed up to discharge after operation, and were divided into groups according to the presence or absence of complications: 418 cases had no complications and 30 cases had complications (including 1 death). Calculate peak oxygen uptake (Peak VO2) and other core indicators, compare the similarities and differences between patients with and without complications, and calculate the best cut value and odds ratio (OR). Results: ①In this study, there were 184 males and 264 females, aged (54±12) (16~79) years old, 85 cases with smoking, 23 cases with lymph node metastasis, 68 cases with hypertension, 45 cases with diabetes. Peak VO2 and Peak WR are respectively (93.31±17.73)(44~158)%pred and (99.70±22.93)(53~179)%pred. FVC, VC and FEV1/FVC are respectively (99.46±15.60)(42~150)%pred, (101.58±15.77)(44~148) %pred and (98.36±9.27)(52~134) %pred. 2There are significant differences(P<0.01) in gender, age, smoking history, lymph node metastasis and core indicators of Peak VO2 (%pred), Peak WR (%pred), FVC, VC, Rest SBP and Peak SBP . There are also differences(P<0.05) in Peak VO2 (ml/(min·kg)), Peak VO2/HR (%pred), VE/VCO2 slope, VE/ VCO2@AT, Peak HR (bmp), RER, FEV1 and fasting blood glucose. No difference in other indicators. ③OR are respectively 4.24 and 3.72 (P<0.01) when the cutting points are Rest SBP(140 mmHg) and FEV1(80%pred). While the OR of Peak VO2(80%pred)、Peak SBP(180 mmHg)、Peak VO2 (20 ml/(min·kg)) and VE/VCO2 Slope(30) are respectively2.66、2.62、2.43 and 2.12 (P<0.05). Conclusion: For patients undergoing thoracoscopic lung resection with good function, the preoperative CPET core indicators can accurately predict the risk of postoperative complications, which is worthy of in-depth study.