Evaluation of myocardial strain assessed by CMR tissue-tracking to predict adverse cardiovascular events in patients with cardiac amyloidosis

Background Cardiac affectation in amyloidosis is presented among 50% patients what implies worse prognostic. Early diagnosis and prognostic stratification is mandatory after the appearance of new therapies that could modify the course of the disease. Purpose The aim of our study was to assess the prognostic value of cardiac magnetic resonance parameters, including Tissue deformation, in cardiac amyloidosis patients. Methods We recruited patients (p) prospectively followed in our cardiomyopathy unit, for a mean period of 10 years (from 2010 to 2020) who were diagnosed with CA. Baseline clinical, laboratory and echocardiographic data were obtained. Contrast-enhanced CMR was performed on a 1.5 T clinical scanner. Routine analysis was performed with a semi-automatic software for volumetric analysis. When late gadolinium enhancement was present, percentage of area of enhancement (LGE) was calculated.All strain parameters were measured off-line using dedicated software. Left ventricular circumferential strain (CS) measurements were obtained using mid-ventricular level short-axis cine views. Longitudinal strain (LS) derived from cine SSFP of 2-, 3-, and 4-chamber long axis views.Finally we evaluated the CMR parameters related with the combined event of mortality and heart failure in the follow-up. Results A total of 98 p were included, with a mean age of 67.5±16.9 years old. Mean follow-up was 42,2±32 months. 22 p (24,4%) had light-chain amyloidosis (AL), 34 p (37,8%) wild type transthyretin amyloidosis (ATTRwt) and 34 p (37,8%) familiar transthyretin amyloidosis (ATTRm). 59p (60,8%) died or present heart failure during the follow-up. Patients who died or present heart failure in the follow-uo had lower left ventricular ejection fraction (48,25±12,2% vs 56,13±11,03%, p=0,003), higher myocardial mass (156,05±54,8g vs 120,84±56,1g, p=0,007), higher LGE (8,6±6,8% vs 4,4±2%), worst GLS (−14,76±6,1% vs −18,67±6,2%) and worst GCS (−23,3±9,7% vs −30,04±9,1%). Both, GLS and GCS were independently associated with the combined event of dead or heart failure when evaluated within a multivariate analysis in a Cox regression model, but GCS was the stronger predictor of events in the follow-up over other CMR parameters like LGE an myocardial mass (p<0,001). Tertile distribution for GCS identified subgroups with different adverse events, particularly for the lowest-risk tertile: GCS <−34%, who had a combinated event in 13,6% of cases, significantly lower than patients in the mid-risk tertile (41,5%) and highest-risk tertile (53,8%) (Log-rank p=0,02) Conclusion Mortality and appearance of heart failure in cardiac amyloid patients is high. The assessment of myocardial strain parameters by CMR tissue-tracking in this population is useful to predict adverse outcomes in the follow-up. Particularly, GCS, stratify patients in subgroups with different risk of events, with added value to classical CMR parameters. FUNDunding Acknowledgement Type of funding sources: None. Death & Heart Failure by GCS

Functional recovery after percutaneous revascularization of coronary chronic total occlusions: insights from cardiac magnetic resonance tissue tracking

To evaluate the effect of percutaneous coronary intervention (PCI) of coronary chronic total occlusions (CTOs) on left ventricular (LV) strain assessed using cardiac magnetic resonance (CMR) tissue tracking. In 150 patients with a CTO, longitudinal (LS), radial (RS) and circumferential shortening (CS) were determined using CMR tissue tracking before and 3 months after successful PCI. In patients with impaired LV strain at baseline, global LS (10.9 ± 2.4% vs 11.6 ± 2.8%; P = 0.006), CS (11.3 ± 2.9% vs 12.0 ± 3.5%; P = 0.002) and RS (15.8 ± 4.9% vs 17.4 ± 6.6%; P = 0.001) improved after revascularization of the CTO, albeit to a small, clinically irrelevant, extent. Strain improvement was inversely related to the extent of scar, even after correcting for baseline strain (B = − 0.05; P = 0.008 for GLS, B = − 0.06; P = 0.016 for GCS, B = − 0.13; P = 0.017 for GRS). In the vascular territory of the CTO, dysfunctional segments showed minor improvement in both CS (10.8 [6.9 to 13.3] % vs 11.9 [8.1 to 15.0] %; P < 0.001) and RS (14.2 [8.4 to 18.7] % vs 16.0 [9.9 to 21.8] %; P < 0.001) after PCI. Percutaneous revascularization of CTOs does not lead to a clinically relevant improvement of LV function, even in the subgroup of patients and segments most likely to benefit from revascularization (i.e. LV dysfunction at baseline and no or limited myocardial scar).

Quantitative Assessment of Left and Right Atrial Strains Using Cardiovascular Magnetic Resonance Based Tissue Tracking

Background: Left and right atrium (LA and RA) exert an essential and dynamic role in ventricular filling and hence affect heart performance. Strain quantification has been reported as a novel parameter to assess function. However, the assessment of bi-atrial strains with cardiovascular magnetic resonance (CMR) based techniques is still limited and gender- and age-specific normal values in a healthy population are missing.Methods: One hundred and fifty healthy volunteers (49.8 ± 17.3 years, 75 males) undergoing 1.5 Tesla CMR examination were retrospectively and consecutively recruited. LA and RA free wall (RAFW) radial and longitudinal strains (RS and LS) associated with atrial reservoir, conduit and booster pump functions were evaluated with CMR based tissue tracking (CMR-TT) technique.Results: The reservoir, conduit and pump LS resulted as 30.7 ± 10.2%, 19.5 ± 8.2%, 10.9 ± 3.7% for LA, and 52.2 ± 17.6%, 33.3 ± 14.2%, 19.1 ± 8.5% for RAFW, respectively. The amplitude of RA strains was significantly larger than that of LA strains, except for conduit RS. With the increase of age, the decrement of majority of reservoir and conduit strains were observed, while pump strains remained unaffected. Females presented with significantly larger RAFW strains compared with males, especially in the elderly. In addition to the positive correlation between atrial strains and emptying fraction, the negative correlation between atrial strains and volume index was also confirmed. Intra-observer reproducibility of LA strains was superior to RAFW strains (coefficient of variation: 10.12–17.04% vs. 10.80–27.36%, respectively), and the measurement of reservoir and conduit strains was more reproducible in comparison with pump strain.Conclusion: CMR-TT is a feasible and reproducible technique to quantify LA and RA strains and determine atrial phasic functions. The existence of age- and gender-related difference of strains suggests the necessity to establish specific normal values for individual populations.

Radial global strain by cardiac magnetic resonance imaging predicts arrhythmic outcomes in hypertrophic cardiomyopathy

Funding Acknowledgements Type of funding sources: None. Introduction Hypertrophic cardiomyopathy (HCM) is a relatively prevalent condition associated with arrhythmic events and sudden cardiac death. Several tools are currently available to identify which HCM patients are at risk of developing these events. Purpose We aimed to evaluate the association of Tissue Tracking strain analysis by cardiac magnetic resonance (CMR) and the development of arrhythmic events in patients with HCM. Methods We prospectively analyzed 136 consecutive patients with HCM diagnosis (established according to current clinical practice guidelines) from January 2006 to October 2017. Every routine 24 hours ECG-monitoring test was registered and looked for sustained or non-sustained ventricular tachycardia (any VT). CMR studies were performed following our predefined CMR protocol for HCM with 1.5T magnets. Cine images were obtained with standard, retrospectively gated, steady-state free-precession (SSFP) sequences in 2, 3 and 4 chambers views and in 10–15 contiguous short-axis slices covering the ventricles from the base to the apex, with breath holding. The strain evaluation was performed by a commercially available Tissue Tracking analysis software, manually defining the endocardial border in short axis, 4, 3 and 2 chambers views and, after verifying adequate identification of the different structures, running the strain analysis (Figure 1, displaying myocardium identification by the strain analysis software). Results Mean follow-up was 49 ± 45 months. Mean age was 61 ± 15 years old (p for the comparation between the group with arrhythmic and the group without arrhythmic events 0.212) and 31% of patients were women (p 0.420). Mean ejection fraction was 69 ± 9.21% (p 0.223) and mean HCM-SCD (hypertrophic cardiomyopathy sudden cardiac death) risk score was 2.20 ± 1.34 (p &lt;0.001). Median percentage of total myocardium showing late gadolinium enhancement (LGE) was 0.61 (interquartile range 2.9; p 0.170). Mean global radial strain (GRS) was 26.23 ± 8.78% (p &lt;0.001). 21 VT episodes were recorded during follow-up. GRS showed an area under de ROC curve of 0.75 predicting VT during follow-up, selecting the value of 27% as the best sensitivity/specificity cutoff point. Statistically significant differences were not found when analyzing global circumferential strain (GCS) and global longitudinal strain (GLS) as VT predictors after adjusting for possible confusion factors (GRS, GCS and GLS distributions depicted in Figure 2). A binary GRS ≥27%/&lt;27% variable was included in a logistic regression model adjusted by age, percent of total myocardium mass showing LGE and HCM-SCD risk score. Significantly more arrhythmic events were found to occur in patients with a GRS &lt;27% (OR 7.33; 95% confidence interval 1.07 – 50.41; p 0.043) after adjusting by age, percent of total myocardium mass showing LGE, and HCM-SCD risk score Conclusions A GRS value of &lt;27% on CMR appears to be a good predictor of worse arrhythmic prognosis in patients with HCM.

Cardiac magnetic resonance strain as a predictor of clinical events in hypertrophic cardiomyopathy

Funding Acknowledgements Type of funding sources: None. Introduction Hypertrophic cardiomyopathy (HCM) is a relatively prevalent condition associated with cardiovascular death and heart failure. Several tools are currently available to identify which HCM patients are at risk of developing these events. Purpose We aimed to evaluate the association of new Tissue Tracking strain analysis by cardiac magnetic resonance (CMR) and the development of clinical events in patients with HCM. Methods We prospectively analyzed 136 consecutive patients with HCM diagnosis (established according to current clinical practice guidelines) from January 2006 to October 2017. Heart failure hospital admissions and death on follow-up were included in a combined clinical outcome. CMR studies were performed following our predefined CMR protocol for HCM with 1.5T magnets. Cine images were obtained with standard, retrospectively gated, steady-state free-precession (SSFP) sequences in 2, 3 and 4 chambers views and in 10–15 contiguous short-axis slices covering the ventricles from the base to the apex, with breath holding. The strain evaluation was performed by a commercially available Tissue Tracking analysis software, manually defining the endocardial border in short axis, 4, 3 and 2 chambers views and, after verifying adequate identification of the different structures, running the strain analysis (Figure 1, displaying myocardium identification by the strain analysis software). Results Mean follow-up was 49 ± 45 months. Mean age was 61 ± 15.33 years old (p 0.024) and 31% of patients were women (p 0.01). 20% had atrial fibrillation (p 0.154). Mean ejection fraction was 69 ± 9.21% (p 0.762) and mean HCM-SCD (hypertrophic cardiomyopathy sudden cardiac death) risk score was 2.20 ± 1.35 (p 0.885). Mean global radial systolic strain rate (GRSsr) was -1,33 ± 0.59 s-1 (p 0.083). During follow-up, 12 heart failure hospital admissions and 14 death from any cause were registered. GRSsr showed an area under de ROC curve of 0.63 (95% confidence interval -CI- 0.51 – 0.75) predicting clinical events. The value of 1.40 s−1 was selected as the best sensitivity/specificity cutoff point. Three variables (sex, age, and previous history of atrial fibrillation) were chosen (through the allsets method) and included as adjusting variables together with &lt;1,40 s−1/≥1.40 s−1 in a multivariate Cox’s regression model (p 0.002; AIC 99.7; Harrell C index 0.82). Patients with GRSsr &lt;1.40 s−1 showed more clinical evens on follow-up vs those with GRSsr ≥1.40 s−1 (adjusted HR 6.57; 95% CI 2.01 – 21.49; p 0.002; Figure 2, displaying Kaplan-Meier survival estimates). Conclusions A GRSsr &lt;1.40 s−1 emerges as a novel independent predictor of worse clinical outcomes in patients with HCM and preserved ejection fraction.