Standardized angiographic projections allow evaluation of coronary artery side branches with quantitative flow ratio (QFR)

Quantitative flow ratio (QFR) is a novel, software-based noninvasive method for the quantitative evaluation of coronary physiology. QFR results correlate with invasive FFR measurements in the three main epicardial coronary arteries. However, QFR data for the evaluation of coronary side branches (SB) are scarce. The evaluation of QFR-performance of SB was retrospective and prospective. Eighty-seven patients with suspected chronic coronary syndrome, who received angiography using routine core lab projections, were retrospectively analyzed. On the second part 37 patients, who received angiography using recommended standardized coronary angiography projections, were prospectively analyzed. Quantitative analysis was performed for SB with a maximum lumen diameter proximal of ≥2 mm based on quantitative coronary angiography (QCA) by two certified experts with the software QAngio XA 3D 3.2. Using routine projections, QFR computation in 55 % of the SB were obtained (123 out of 224). Using standardized projections, 85 % of SB were computed by QFR (64 out of 75; p < 0.001 vs routine projections). The fluoroscopy time for recommended projections was not significantly different as opposed to routine projections (3.75 ± 2.2 vs. 4.58 ± 3.00 min, p = 2.6986). Using the standardized projections was associated with a higher amount of contrast medium (53.44 ± 24.23 vs. 87.95 ± 43.73 ml, p < 0.01), longer overall procedure time (23.23 ± 16.35 vs. 36.14 ± 17.21 min, p < 0.01) and a higher dose area product (1152.28 ± 576.70 vs. 2540.68 ± 1774.07 cGycm2, p < 0.01). Our study shows that the blood flow of the vast majority of coronary SB can be determined non-invasively by QFR in addition to the main epicardial coronary arteries when standardized projections are used.

Comparison of quantitative flow ratio (QFR) and instantaneous wave-free ratio (iFR) or resting full-cycle ratio (RFR) during daily routine in the catheterization laboratory

Background

The prognosis of patients with coronary artery disease (CAD) depends strongly on the hemodynamic relevance of the stenosis. The gold standard is the invasive evaluation of the stenosis using Fractional Flow Reserve (FFR), instantaneous wave-free ratio (iFR) or Resting Full-Cycle Ratio (RFR). The use of invasive procedures remains low due to procedural factors and costs. Quantitative Flow Ratio (QFR) is a novel, software-based method to evaluate the physiology of coronary lesions during cardiac catheterization. Computing a three-dimensional model of the vessel based on two angiographic recordings and analyzing the fluid dynamics of the contrast medium flow, the software computes the FFR. In the setting of clinical studies, it has been demonstrated that QFR is feasible and correlates well with FFR. The aim of this study is to compare feasibility and reliability of QFR with established measurements of the iFR or RFR in daily routine.

Methods

Patients with an indication for an invasive coronary angiography and a stenosis of 30 to 90% were simultaneously assessed using QFR and iFR/RFR in a routine setting. The QFR-computation was performed online by a certified expert with QAngio XA 3D 3.2. The following outcome parameters were analyzed: time to result, volume of applicated contrast medium, applicated dose area product, result of the evaluation. The results have been registered for both methods, respectively.

Results

102 coronary arteries were analyzed using QFR and iFR or RFR. QFR shows a good correlation (r=0.753, AUC=0.922) and accuracy (agreement 89.22%, sensitivity 95.83%, specificity 83.33%, PPV 83.64%, NPV 95.74%). The data show that QFR delivers significantly faster results and reduces the procedure related applicated radiation dose from in median 598.8 cGy cm2 to 306.75 cG ycm2 (p&lt;0.001). The study shows no significant difference regarding the amount of contrast medium used.

Conclusion

QFR has a good diagnostic agreement and can reduce procedure length and applicated radiation dose. Thereby QFR could increase the use of physiologically guided coronary interventions in daily routine.

Funding Acknowledgement

Type of funding sources: None.

Evaluation of coronary artery side branches (SB) with Quantitative Flow Ratio (QFR) by comparing the use of recommended angiographic projections with routine angiographic projections as Reference

Background

Contrast-flow quantitative flow ratio (QFR) is a novel, noninvasive method for the quantitative evaluation of coronary physiology using computational fluid dynamics based on 3D vessel reconstruction in angiograms. Computing this 3D-model with analyzing the dynamics of the contrast medium flow with a specialized algorithm, the software computes the virtual FFR. This new technique has shown a high accuracy in determining the functional significance of coronary stenosis of the three main epicardial coronary arteries using the gold standard FFR as reference. However, QFR data for the evaluation of coronary side branches (SB) are scarce. Therefore, the study aimed to determine the feasibility of this novel method to analyze SB and to characterize optimal viewing angles for evaluation using QFR.

Methods

A total of 87 patients, who underwent invasive coronary angiography with routine core lab projections, were enrolled in the study and were analyzed retrospectively by two certified experts with the software QAngio XA 3D 3.2. In addition, 37 patients were enrolled prospectively using coronary angiography projections recommended for the virtual QFR-Analysis. Quantitative Analysis was performed only for SB with a maximum lumen diameter (MLD) of ≥2mm. The following outcome parameters were analyzed: baseline characteristics, anatomical SB parameters such as MLD (mm) and vessel length (VL; mm) of the SB, result of the QFR-computation and procedure parameters, such as use of applicated contrast medium and fluoroscopy time.

Results

187 side branches (obtuse marginal [OM], diagonal branch [DB], intermediate artery [IA], posterolateral branch [PLB] and posterior descending artery [PDA]) were analyzed using QFR. Out of 87 patients undergoing an invasive coronary angiography with routine core lab projections with 244 SB ≥2mm, 123 SB (55%) were computable with the use of QFR. In the prospective cohort of 37 patients with recommended angiographic projections for QFR analysis of main branches, 75 SB ≥2mm were found. 64 of the 75 SB (84%) were computable with the use of QFR. The use of recommended projections led to an overall higher evaluability of SB (85% vs. 55%). The data show that the fluoroscopy time for recommended QFR projections was not significantly different as the time for routine cath lab projections (3.7±2.2 vs. 4.6±3, p=2.69). The study shows a significant increase of the amount of contrast medium used for QFR projections (55.4±24.2 vs. 87.9±43.7, p&lt;0.01).

Conclusion

To our knowledge this is the first study evaluating QFR for SB analysis. QFR is feasible for the routine assessment of side branches (SD) with MLD ≥2mm. The use of recommended projections significantly improved the quality of the QFR SB analysis apart from PDA, without increasing the fluoroscopy time during coronary angiography. Overall QFR could increase the use of physiologically guided coronary interventions, not only for the main epicardial vessels, but also for the SB.

Funding Acknowledgement

Type of funding sources: None.

Prognostic value of secondary cardiac alterations in patients with moderate aortic valve stenosis

Purpose

Echocardiographic characteristics that predict the progression of moderate aortic valve stenosis (mAS) are lacking. The aim of the present study was to evaluate the prognostic value of left ventricular hypertrophy (LVH), diastolic dysfunction (DD) and pulmonary artery hypertension (PAH) in patients with mAS.

Methods

A total of 137 patients with asymptomatic mAS (age 72±10 years; females: 51 (37%); Blood Pressure: 143±21 / 78±13 mmHg) were included. Echocardiography was performed at baseline and at follow-up every six or/and twelve months. Patients with concomitant valvular defects, hypertrophic cardiomyopathy or chronic obstructive pulmonary disease were excluded. mAS was defined by current guideline criteria. Left ventricular ejection fraction (LVEF), LVH (LV mass index, males: &gt;115g/m2, females: &gt;95 g/m2), DD (E/e' &gt;14) and PAH (maximum regurgitant velocity of tricuspid valve (TRVmax) &gt;2.8m/s) were assessed.

mAS patients were divided into 4 subgroups based on the number of secondary cardiac alterations: (0) no; (1) one; (2) two; (3) three cardiac alterations. The primary endpoint was progression to severe AS with indication for treatment (effective aortic orifice area (EOA) by continuity equation &lt;1 cm2/&lt;0.6 cm2/m2) or the onset of symptoms.

Results

mAS patients showed (0) no secondary cardiac alterations in 20% (n=28), (1) one in 40% (n=55), (2) two in 26% (n=35) and (3) three in 14% (n=19). Among mAS subgroups, no significant differences were observed for age and comorbidities. Echocardiographic parameters are summarised in Tab.1. In general, mAS patients with ≥ two cardiac alterations showed significantly smaller EOA ((0): 1.32±0.19 vs. 1.29±0.19, p&gt;0.05; (1): 1.26±0.21 vs. 1.18±0.21, p&gt;0.05; (2): 1.29±0.20 vs. 1.01±0.20, p&lt;0.01; (3): 1.31±0.16 vs. 1.06±0.25, p&lt;0.01) and higher mean pressure gradients (PGmean) ((0): 19.8±6.64 vs. 21.8±6.32, p&gt;0.05; (1): 20.0±9.26 vs. 22.3±9.94, p&gt;0.05; (2): 22.7±9.32 vs. 30.5±12.61, p&lt;0.01 (3): 25.0±8.87 vs. 29.4±10.67, p&lt;0.01) between baseline and follow-up (mean follow-up 20±9 months). Further, decrease of EOA/days was significantly higher in these patients ((0) −0.003; (1) −0.006; (2) −0.016; (3) −0.028; p&lt;0.01, Fig. 1). As shown in Kaplan-Meier curve, mAS with ≥ two cardiac alterations showed rapid progression of moderate to severe AS (Fig. 2).

Conclusions

In 40% of patients with mAS ≥ two secondary cardiac alterations (LV hypertrophy, DD and PAH) were observed. The presence of ≥ two of these secondary cardiac alterations is associated with rapid progression of mAS.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

P2701Comparison of myocardial ischemia assessed by contrast-flow quantitative flow ratio (cQFR) and by stress MRI in patients with stable coronary artery disease

Background

Contrast-flow quantitative flow ratio (cQFR) is a new technology for evaluation of coronary stenosis. cQFR allows to derive the fractional flow reserve (FFR) from coronary angiograms. Based on a three dimensional coronary model, FFR is calculated from computational fluid dynamics. Head to head comparisons with FFR showed an overall diagnostic accuracy of 85%. cQFR does not require coronary wires or hyperemia. However, the ability of cQFR to detect myocardial ischemia is unknown. Therefore, the aim of this study was to evaluate the relationship between cQFR and myocardial ischemia assessed by stress magnetic resonance imaging (stress MRI).

Methods

cQFR analysis was performed in patients selected from the hospital database who received stress MRI and coronary angiography. A relevant ischemia on stressMRI was defined as a perfusion deficit in ≥2 of 16 segments. The cQFR was based on 3-dimensional quantitative coronary angiography (3D-QCA) using the QAngio XA 3D 1.1, Medis Medical Imaging System, Leiden, The Netherlands. Two blinded investigators analysed all 3 main coronary vessels of each patient measuring diameter stenosis (DS), area stenosis (AS) and cQFR. A cQFR of ≤0.8 was considered abnormal. The primary endpoint was sensitivity and specificity of cQFR using stress MRI as a reference standard.

Results

125 vessels of 53 patients could be fully analysed by cQFR (78.6%). The sensitivity of cQFR in detecting significant epicardial stenoses of coronary vessels with documented ischemia in stress MRI was 75%, the specificity was 87%. The 3D-QCA-derived diameter stenoses and area stenoses in vessels with positive stress MRI were significantly higher than in vessels without ischemia (see Table 1).

Table 1. Means of diameter stenosis (DS) und area stenosis (AS) with interquartile range (IQR) Total (n=125) Ischemia (n=32) No Ischemia (n=93) p-value DS [%] 42.3 (28.3–53.1) 57.1 (47–68.5) 37.7 (27.6–45.1) <0.0001 AS [%] 51.8 (32.4–69.7) 68.9 (56.8–85.9) 46.5 (29.7–62.7) <0.0001

Conclusion

The analysis reveals a high correlation between relevant coronary stenosis measured by cQFR and ischemic areas detected by stress MRI. Differences between the two methods are plausible because stress MRI detects ischemia due to other reasons than epicardial stenosis. Further randomized studies are mandatory to verify the prognostic significance of the cQFR measurements.

Differentially expressed genes in L6 rat skeletal muscle myoblasts after incubation with inflammatory cytokines

OBJECTIVE

The mechanism underlying exercise intolerance in chronic heart failure is still unclear. An increased concentration of inflammatory cytokines could be detected in the serum of patients with chronic heart failure (CHF) exhibiting a correlation with the severity of the disease. The variety of molecular alterations triggered by these cytokines in the skeletal muscle is almost unknown. The study was designed to analyze the differential gene expression in skeletal muscle myoblasts after stimulation with inflammatory cytokines.

METHODS

L6 rat skeletal muscle myoblasts were incubated for 24 h with a combination of IL-1beta/IFN-gamma and the differential gene expression profile was determined by a PCR-based subtractive hybridization method.

RESULTS

Out of 173 picked clones 141 different sequences could be identified. By comparison with Genebank, the identity of 73 genes (51.7%) could be confirmed, whereas the rest did not show a homology to any known gene. Some of the identified genes are known to be altered in patients with CHF.

CONCLUSION

In summary, the results of this study provide information about changes in gene expression after exposure of skeletal muscle cells to inflammatory cytokines. This information may yield a new gene pool, worthwhile to be analyzed in skeletal muscle of patients with chronic heart failure.