Comparison of different sowtware solutions for AVC quantification using contrast enhanced MDCT

Funding Acknowledgements

Type of funding sources: None.

Aims

Estimating aortic valve calcification (AVC) derived from multi detector computed tomography (MDCT) scans in aortic stenosis (AS) patients has gained increasing interest for diagnostic and prognostic reasons. Little is known about the interchangeability of AVC obtained from different software solutions which, was systematically determined in consecutive patients undergoing contrast enhanced MDCT before TAVR.

Methods and results

50 randomly selected patients who underwent contrast enhanced MDCT for TAVR planning were included in the analysis. All MDCT data sets were analysed using three different software vendors (3 Mensio, CVI 42, Snygo.Via). AVC score was expressed as mm³. For analysing intra- and inter-observer variability a subset of 10 patients were analysed twice with at least 2 weeks in between the measurements. Intra- and inter-observer variability was quantified using the ICC reliability method, Bland-Altman analysis and coefficients of variation.

AVC scores were successfully obtained using all software solutions (3 Mensio 941 ± 623, CVI42 941 ± 637, Syngo.Via 948 mm³ ± 655) without significant differences (p = 0.455). There was excellent intra- (3 Mensio: ICC 0.999 [0.995 – 1.000], COV 3.86 %, mean difference -19.28 [± 45.07]; CVI 42: ICC 1.000 [0.999 – 1.000], COV 1.6 %, mean difference -10.28 [± 18.6]; Syngo.Via: ICC 0.998 [0.993 – 1.000], COV 4.13 %, mean difference -24.81 [± 48.52]) and inter-observer variability (3 Mensio: ICC 1.000 [0.999 – 1.000], COV 1.38 %, mean difference -7.14 [± 16.20]; CVI 42: ICC 1.000 [1.000 – 1.000], COV 1.01 %, mean difference -1.74 [± 11.83]; Syngo.Via: ICC 0.996 [0.985 – 0.999], COV 6.68 %, mean difference -0.65 [± 79.43]) for all software types. Best inter-vendor agreement was found between CVI 42 and Syngo.Via (ICC 0.997 [CI 0.995-0.998], COV 7.26 %, mean difference -7 [± 68.60]) followed by 3 Mensio / CVI 42 (ICC 0,996 [CI 0,922-0,998], COV 8.95 %, mean difference -0.06 [± 84.16]) and 3 Mensio / Syngo.Via (ICC 0,992 [CI 0,986-0,995], COV 12.19%, mean difference -7.06 [± 115.07]).

Conclusion

Contrast enhanced MDCT derived AVC scores are interchangeable between and reproducible within different commercially available software solutions. This is important since sufficient reproducibility, inter-changeability and valid results represent prerequisites for accurate TAVR planning and wide spread clinical use.

Aortic valve calcification and endomyocardial fibrosis determine adverse outcomes following transcatheter aortic valve replacement

Funding Acknowledgements

Type of funding sources: None.

Aims

There is evidence to suggest that subtype of aortic stenosis (AS), degree of myocardial fibrosis (MF) and level of aortic valve calcification (AVC) are associated with adverse cardiac outcome in AS. Since little is known about their respective contribution, we sought to investigate their relative importance and interplay as well as association with adverse cardiac events.

Methods

100 consecutive patients with severe AS and indication for transfemoral transcatheter aortic valve replacement (TAVR) were prospectively enrolled between January 2017 and October 2018. Patients underwent transthoracic echocardiography, multi detector computed tomography (MDCT) and left ventricular endomyocardial biopsy at the time of TAVR.

Results

The final study cohort consisted of 92 patients with completed study protocol comprising of 39 (42.4 %) normal ejection fraction high gradient (NEFHG), 13 (14.1 %) low EF high gradient (LEFHG), 25 (27.2 %) low EF (flow) low gradient (LEFLG) and 15 (16.3 %) paradoxical low flow low gradient (PLFLG) AS. The high gradient phenotypes (NEFHG and LEFHG) showed the largest amount of AVC (807 ± 421; 813 ± 281 mm³ respectively) as compared to the low gradient phenotypes (LEFLG and PLFLG; 503 ± 326; 555 ± 594 mm³ respectively, p < 0.05). Conversely, MF was most prevalent in low output phenotypes (LEFLG > LEFHG > PLFLG > HEFHG, p < 0.05). This was paralleled by larger cardiovascular mortality within 600 days post TAVR (LEFLG n = 7 > PLFLG n = 4 > LEFHG n = 2 > NEFHG n = 1). In Patients with high MF burden a higher AVC was associated with a lower mortality (p = 0.045, HR = 0.261, 95%CI 0.07-0.97). Within LEFLG AS, patients with larger AVC (>476.8 mm³) had larger MF (40.2%) and higher cardiovascular mortality (n = 5) as compared to patients with lower AVC (£476.8 mm³, 17.1% MF, p = 0.027, cardiovascular mortality n = 2).

Conclusion

MF is associated with adverse cardiovascular outcome following TAVR which is most prevalent in low ejection fraction situations. In the presence of large MF burden patients with large AVC have better outcome following TAVR. Conversely worse outcome in large MF and relatively little AVC may be explained by a relative prominence of an underlying cardiomyopathy while better survival rates in large AVC patients may indicate severe AS associated pressure overload relief and subsequently improved survival following TAVR.

Real-time cardiac magnetic resonance tissue characterisation for fibrosis assessment in aortic stenosis

Background

Myocardial fibrosis is a major determinant of outcome in aortic stenosis (AS). Novel fast real-time (RT) cardiac magnetic resonance (CMR) mapping techniques allow comprehensive quantification of fibrosis but have not yet been adequately validated against standard techniques and histology.

Methods

Patients with severe AS underwent CMR before (n=110) and left ventricular (LV) endomyocardial biopsy (n=46) at transcatheter aortic valve replacement (TAVR). Midventricular short axis native, post-contrast T1 and extracellular volume fraction (ECV) maps were generated using commercially available 5(3)3 MOLLI and RT single-shot inversion recovery fast low-angle shot (FLASH) with radial undersampling. ECV and LV mass were used to calculate LV matrix volumes. Variability and agreements were assessed between RT, MOLLI and histology using intraclass correlation coefficients, coefficients of variation and Bland Altman analyses.

Results

RT and MOLLI derived ECV were similar for myocardium (26.2 vs. 26.5, p=0.073) and inter-ventricular septum (26.2 vs. 26.5, p=0.216). MOLLI native T1 time was in median 20 ms longer compared to RT (p<0.001). Agreement between RT and MOLLI was best for ECV (ICC >0.91), excellent for post-contrast T1 times (ICC >0.81) and good for native T1 times (ICC >0.62). Diffuse collagen volume fraction by biopsies was in median 7.8%. ECV (RT r=0.345, p=0.039; MOLLI r=0.40, p=0.010) and LV matrix volumes (RT r=0.45, p=0.005; MOLLI r=0.43, p=0.007) were the only parameters associated with histology.

Conclusions

RT mapping offers precise T1 and ECV assessments with similar agreement with histology as compared to conventional MOLLI techniques. Single-shot real time techniques may be advantageous in sicker patients prone to dyspnoea or arrhythmia.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Research Foundation

Performance of different myocardial tissue tracking algorithms and acquisition-based strain imaging to characterise myocardial pathology

Background

Myocardial deformation imaging is superior in risk-stratification compared to volumetric approaches. Myocardial Feature-Tracking (FT) allows easy post-processing of routinely acquired cine images. Since there is no clear recommendation regarding FT post-processing we sought to compare different FT-strains with reference standard techniques including tagging and strain encoded (SENC) magnetic resonance imaging.

Methods

CMR-FT software from 4 different vendors (TomTec, Medis, Circle, Neosoft), CMR tagging (Segment) and fastSENC (MyoStrain) were used to determine left ventricular (LV) global longitudinal and circumferential strains (GLS and GCS) in 12 healthy volunteers and 12 heart failure patients. Variability and agreements were assessed using intraclass correlation coefficients, coefficients of variation and Bland Altman plots.

Results

Compared to tagging, FT-based strain was software independently significantly higher except for GCS using Medis (p=0.178). Compared to fSENC, mean-differences of GLS were smaller within a range of ±1.5%. For GCS this only applied to CVI and Medis (<1.5%) but not TomTec (>7%) or Neosoft (>4%). Absolute agreements comparing FT to tagging were best for CVI (GLS ICC0.70) and Medis (GCS ICC0.85). Compared to fSENC agreement of GLS was generally excellent (ICC>0.77), but only CVI and Medis revealed excellent agreement for GCS (ICC0.88 and 0.85). Consistency and correlation of GLS were software independently high compared with tagging and fSENC (ICC>0.86, r>0.76) while being lower for GCS (ICC>0.68, r>0.72).

Conclusion

Although agreement differs between deformation assessment approaches, consistency and correlation are high irrespective of the method chosen, thus indicating reliable strain assessment. Further standardisation and introduction of uniform references is warranted for clinical routine implementation.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): DZHK - German Centre for Cardiovascular Research

Frequency and prognostic impact of right ventricular involvement in acute myocardial infarction

Background

Right ventricular (RV) involvement complicating myocardial infarction (MI) is thought to impact prognosis, but potent RV markers for risk stratification are lacking.

Purpose

To assess the frequency and prognostic implications of concomitant structural and functional RV injury in MI.

Methods

Cardiac magnetic resonance (CMR) was performed in 1235 patients with MI (STEMI: n=795; NSTEMI: n=440) 3 days after reperfusion by primary percutaneous coronary intervention. Central core laboratory-masked analyses included structural (edema representing reversible ischemia, irreversible infarction, microvascular obstruction [MVO]) and functional (ejection fraction, global longitudinal strain [GLS]) RV alterations. The clinical endpoint was the 12-month rate of major adverse cardiac events (MACE).

Results

RV ischemia and infarction were observed in 19.6% and 12.1% of patients, respectively, suggesting complete myocardial salvage in one-third of patients. RV ischemia was associated with a significantly increased risk of MACE (10.1% versus 6.2%; p=0.035), while patients with RV infarction showed only numerically increased event rates (p=0.075). RV MVO was observed in 2.4% and not linked to outcome (p=0.894). Stratification according to median RV GLS (10.2% versus 3.8%; p<0.001) but not RV ejection fraction (p=0.175) resulted in elevated MACE rates. Multivariable analysis including clinical and left ventricular MI characteristics identified RV GLS as an independent predictor of outcome (hazard ratio 1.05, 95% confidence interval 1.00–1.09; p=0.034) in addition to age (p=0.001), Killip class (p=0.020), and left ventricular GLS (p=0.001), while RV ischemia was not independently associated with outcome.

Conclusions

RV GLS is a predictor of post-infarction adverse events over and above established risk factors, while structural RV involvement was not independently associated with outcome.

Funding Acknowledgement

Type of funding source: None