"Interstitial fibrosis is associated with left atrial remodeling and adverse clinical outcomes in selected low-risk patients with hypertrophic cardiomyopathy"

BACKGROUND

Cardiovascular magnetic resonance (CMR) extracellular volume (ECV) allows non-invasive detection of myocardial interstitial fibrosis, which may be related to diastolic dysfunction and left atrial (LA) remodeling in hypertrophic cardiomyopathy (HCM). While the prognostic role of LGE is well-established, interstitial fibrosis and LA dysfunction are emerging novel markers in HCM. This study aimed to explore the interaction between interstitial fibrosis by ECV, LA morpho-functional parameters and adverse clinical outcomes in selected low-risk patients with HCM.

METHODS

115 HCM patients and 61 matched controls underwent CMR to identify: i) interstitial fibrosis by ECV in hypertrophied left ventricular LGE-negative remote myocardium (r-ECV); ii) LA indexed maximum (LAVi max) and minimum (LAVi min) volumes, ejection fraction (LA-EF) and strain (reservoir εs, conduit εe and booster εa), by CMR feature-tracking. 2D-echocardiographic assessment of diastolic function was also performed within 6 months from CMR. A composite endpoint including worsening NYHA class, heart failure hospitalization, atrial fibrillation and all-cause death was evaluated at 2.3 years follow-up. HCM patients were divided into two groups, according to r-ECV values of controls.

RESULTS

Patients with r-ECV ≥29% (n = 45) showed larger LA volumes (LAVimax 63 vs. 54 ml/m2, p < 0.001; LAVimin 43 vs. 28 ml/m2, p 〈0001), worse LA function (εs 16 vs. 28%, εe 8 vs. 15%, εa 8 vs. 14%, LA-EF 33 vs. 49%, all p < 0.001) and elevated Nt-proBNP (1115 vs. 382 pg/ml, p = 0.002). LA functional parameters inversely correlated with r-ECV (εs r = -0.54; LA-EF r = -0.46; all p < 0.001) and E/e' (εs r = -0.52, LA-EF r = -0.46; all p < 0.006). r-ECV ≥29% and LAVi min >30 ml/m2 have been identified as possible independent factors associated with the endpoint.

CONCLUSIONS

In HCM diffuse interstitial fibrosis detected by increased r-ECV is associated with LA remodeling and emerged as a potential independent predictor of adverse clinical outcomes, on top of the well-known prognostic impact of LGE.

Coronary physiology thresholds associated with microvascular obstruction in myocardial infarction

OBJECTIVES

To ascertain whether invasive assessment of coronary physiology soon after recanalisation of the culprit artery by primary percutaneous coronary intervention is associated with the development of microvascular obstruction by cardiac magnetic resonance in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

Between November 2020 and December 2021, 102 consecutive patients were prospectively enrolled in five tertiary centres in Italy. Coronary flow reserve (CFR) and index of microvascular resistance (IMR) were measured in the culprit vessel soon after successful primary percutaneous coronary intervention. Optimal cut-off points of IMR and CFR to predict the presence of microvascular obstruction were estimated, stratifying the population accordingly in four groups. A comparison with previously proposed stratification models was carried out.

RESULTS

IMR>31 units and CFR≤1.25 yielded the best accuracy. Patients with IMR>31 and CFR≤1.25 exhibited higher microvascular obstruction prevalence (83% vs 38%, p<0.001) and lower left ventricular ejection fraction (45±9% vs 52±9%, p=0.043) compared with those with IMR≤31 and CFR>1.25, and lower left ventricular ejection fraction compared with patients with CFR≤1.25 and IMR≤31 (45±9% vs 54±7%, p=0.025). Infarct size and area at risk were larger in the former, compared with other groups.

CONCLUSIONS

IMR and CFR are associated with the presence of microvascular obstruction in STEMI. Patients with an IMR>31 units and a CFR≤1.25 have higher prevalence of microvascular obstruction, lower left ventricular ejection fraction, larger infarct size and area at risk.

TRIAL REGISTRATION NUMBER

NCT04677257.

Left atrial remodeling in hypertrophic cardiomyopathy and Fabry disease: A CMR-based head-to-head comparison and outcome analysis

BACKGROUND

Hypertrophic cardiomyopathy (HCM) and Fabry disease cardiomyopathy (FD) are phenocopies, as they show left ventricular hypertrophy (LVH). The left atrium (LA) is emerging as a potential marker of disease severity in both cardiomyopathies. The present study compares HCM and FD cardiomyopathy with similar degree of LVH, exploring LA morpho-functional parameters and the correlates of clinical outcome.

METHODS

We performed a comprehensive CMR-based comparison between 30 HCM and 30 FD patients matched on age, sex, BSA, LV mass and major cardiovascular risk factors affecting LA remodeling (arterial hypertension and diabetes). 30 healthy controls were also included. CMR feature tracking (CMR-FT) analysis, T1 mapping and conventional parameters were evaluated. Patients also underwent transthoracic echocardiography for LV diastolic function assessment. Clinical events at follow-up were collected (atrial and ventricular events, bradyarrhythmia, heart failure (HF) hospitalization and death).

RESULTS

HCM patients showed greater LA remodeling compared to FD patients, namely higher LA end-systolic volume index (LAVi max), lower LA-ejection fraction (LA-EF) and worse reservoir (εs) and booster function (εa) (all p < 0.05). Accordingly, these parameters have demonstrated good potential for distinguishing between FD and HCM (AUC 0.68-0.73, all p < 0.05), with LAVi max being an independent predictor for HCM diagnosis (OR 1.07, 95%CI 1.011-1.132, p 0.02). Moreover, in HCM patients a significant association between εs and HF occurrence was observed at 2-year follow-up (OR 0.85, 95%CI 0.72-0.99, p 0.04).

CONCLUSIONS

In HCM, LA remodeling is greater than in FD cardiomyopathy with similar LVH, and reservoir strain is associated with HF at follow-up.

Cardiac Magnetic Resonance for Prophylactic Implantable-Cardioverter Defibrillator Therapy in Ischemic Cardiomyopathy: The DERIVATE-ICM International Registry

BACKGROUND

Implantable cardioverter-defibrillator (ICD) therapy is the most effective prophylactic strategy against sudden cardiac death (SCD) in patients with ischemic cardiomyopathy (ICM) and left ventricle ejection fraction (LVEF) ≤35% as detected by transthoracic echocardiograpgy (TTE). This approach has been recently questioned because of the low rate of ICD interventions in patients who received implantation and the not-negligible percentage of patients who experienced SCD despite not fulfilling criteria for implantation.

OBJECTIVES

The DERIVATE-ICM registry (CarDiac MagnEtic Resonance for Primary Prevention Implantable CardioVerter DebrillAtor ThErapy; NCT03352648) is an international, multicenter, and multivendor study to assess the net reclassification improvement (NRI) for the indication of ICD implantation by the use of cardiac magnetic resonance (CMR) as compared to TTE in patients with ICM.

METHODS

A total of 861 patients with ICM (mean age 65 ± 11 years, 86% male) with chronic heart failure and TTE-LVEF <50% participated. Major adverse arrhythmic cardiac events (MAACE) were the primary endpoints.

RESULTS

During a median follow-up of 1,054 days, MAACE occurred in 88 (10.2%). Left ventricular end-diastolic volume index (HR: 1.007 [95% CI: 1.000-1.011]; P = 0.05), CMR-LVEF (HR: 0.972 [95% CI: 0.945-0.999]; P = 0.045) and late gadolinium enhancement (LGE) mass (HR: 1.010 [95% CI: 1.002-1.018]; P = 0.015) were independent predictors of MAACE. A multiparametric CMR weighted predictive derived score identifies subjects at high risk for MAACE compared with TTE-LVEF cutoff of 35% with a NRI of 31.7% (P = 0.007).

CONCLUSIONS

The DERIVATE-ICM registry is a large multicenter registry showing the additional value of CMR to stratify the risk for MAACE in a large cohort of patients with ICM compared with standard of care.

Effect of Migalastat on cArdiac InvOlvement in FabRry DiseAse: MAIORA study

BACKGROUND

A small but significant reduction in left ventricular (LV) mass after 18 months of migalastat treatment has been reported in Fabry disease (FD). This study aimed to assess the effect of migalastat on FD cardiac involvement, combining LV morphology and tissue characterisation by cardiac magnetic resonance (CMR) with cardiopulmonary exercise testing (CPET).

METHODS

Sixteen treatment-naïve patients with FD (4 women, 46.4±16.2 years) with cardiac involvement (reduced T1 values on CMR and/or LV hypertrophy) underwent ECG, echocardiogram, troponin T and NT-proBNP (N-Terminal prohormone of Brain Natriuretic Peptide) assay, CMR with T1 mapping, and CPET before and after 18 months of migalastat.

RESULTS

No change in LV mass was detected at 18 months compared to baseline (95.2 g/m2 (66.0-184.0) vs 99.0 g/m2 (69.0-121.0), p=0.55). Overall, there was an increase in septal T1 of borderline significance (870.0 ms (848-882) vs 860.0 ms (833.0-875.0), p=0.056). Functional capacity showed an increase in oxygen consumption (VO2) at anaerobic threshold (15.50 mL/kg/min (13.70-21.50) vs 14.50 mL/kg/min (11.70-18.95), p=0.02), and a trend towards an increase in percent predicted peak VO2 (72.0 (63.0-80.0) vs 69.0 (53.0-77.0), p=0.056) was observed. The subset of patients who showed an increase in T1 value and a reduction in LV mass (n=7, 1 female, age 40.5 (28.6-76.0)) was younger and at an earlier disease stage compared to the others, and also exhibited greater improvement in exercise tolerance.

CONCLUSION

In treatment-naïve FD patients with cardiac involvement, 18-month treatment with migalastat stabilised LV mass and was associated with a trend towards an improvement in exercise tolerance. A tendency to T1 increase was detected by CMR. The subset of patients who had significant benefits from the treatment showed an earlier cardiac disease compared to the others.

TRIAL REGISTRATION NUMBER

NCT03838237.

Cardiac magnetic resonance for prophylactic implantable-cardioverter defibrillator therapy international study: prognostic value of cardiac magnetic resonance-derived right ventricular parameters substudy

AIMS

Right ventricular systolic dysfunction (RVSD) is an important determinant of outcomes in heart failure (HF) cohorts. While the quantitative assessment of RV function is challenging using 2D-echocardiography, cardiac magnetic resonance (CMR) is the gold standard with its high spatial resolution and precise anatomical definition. We sought to investigate the prognostic value of CMR-derived RV systolic function in a large cohort of HF with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

Study cohort comprised of patients enrolled in the CarDiac MagnEtic Resonance for Primary Prevention Implantable CardioVerter DefibrillAtor ThErapy registry who had HFrEF and had simultaneous baseline CMR and echocardiography (n = 2449). RVSD was defined as RV ejection fraction (RVEF) <45%. Kaplan-Meier curves and cox regression were used to investigate the association between RVSD and all-cause mortality (ACM). Mean age was 59.8 ± 14.0 years, 42.0% were female, and mean left ventricular ejection fraction (LVEF) was 34.0 ± 10.8. Median follow-up was 959 days (interquartile range: 560-1590). RVSD was present in 936 (38.2%) and was an independent predictor of ACM (adjusted hazard ratio = 1.44; 95% CI [1.09-1.91]; P = 0.01). On subgroup analyses, the prognostic value of RVSD was more pronounced in NYHA I/II than in NYHA III/IV, in LVEF <35% than in LVEF ≥35%, and in patients with renal dysfunction when compared to those with normal renal function.

CONCLUSION

RV systolic dysfunction is an independent predictor of ACM in HFrEF, with a more pronounced prognostic value in select subgroups, likely reflecting the importance of RVSD in the early stages of HF progression.

The use of dedicated long-axis views focused on the left atrium improves the accuracy of left atrial volumes and emptying fraction measured by cardiovascular magnetic resonance

BACKGROUND

The use of apical views focused on the left atrium (LA) has improved the accuracy of LA volume evaluation by two-dimensional (2D) echocardiography. However, routine cardiovascular magnetic resonance (CMR) evaluation of LA volumes still uses standard 2- and 4-chamber cine images focused on the left ventricle (LV). To investigate the potential of LA-focused CMR cine images, we compared LA maximuml (LAVmax) and minimum (LAVmin) volumes, and emptying fraction (LAEF), calculated on both standard and LA-focused long-axis cine images, with LA volumes and LAEF obtained by short-axis cine stacks covering the LA. LA strain was also calculated and compared between standard and LA-focused images.

METHODS

LA volumes and LAEF were obtained from 108 consecutive patients by applying the biplane area-length algorithm to both standard and LA-focused 2- and 4-chamber cine images. Manual segmentation of a short-axis cine stack covering the LA was used as the reference method. In addition, LA strain reservoir (εs), conduit (εe) and booster pump (εa) were calculated using CMR feature-tracking.

RESULTS

Compared to the reference method, the standard approach significantly underestimated LA volumes (LAVmax: bias - 13 ml; LOA =  + 11, - 37 ml; LAVmax i: bias - 7 ml/m2; LOA =  + 7, - 21 ml/m2; LAVmin; bias - 10 ml, LOA: + 9, - 28 ml; LAVmin i: bias - 5 ml/m2, LOA: + 5, - 16 ml/m2), and overestimated LA-EF (bias 5%, LOA: + 23, - 14%). Conversely, LA volumes (LAVmax: bias 0 ml; LOA: + 10, - 10 ml; LAVmax i: bias 0 ml/m2; LOA: + 5, - 6 ml/m2; LAVmin: bias - 2 ml; LOA: + 7, - 10 ml; LAVmin i: bias - 1 ml/m2; LOA: + 3, - 5 ml/m2) and LAEF (bias 2%, LOA: + 11, - 7%) by LA-focused cine images were similar to those measured using the reference method. LA volumes by LA-focused images were obtained faster than using the reference method (1.2 vs 4.5 min, p < 0.001). LA strain (εs: bias 7%, LOA = 25, - 11%; εe: bias 4%, LOA = 15, - 8%; εa: bias 3%, LOA = 14, - 8%) was significantly higher in standard vs. LA-focused images (p < 0.001).

CONCLUSION

LA volumes and LAEF measured using dedicated LA-focused long-axis cine images are more accurate than using standard LV-focused cine images. Moreover, LA strain is significantly lower in LA-focused vs. standard images.

Collateral presence and extent do not predict myocardial viability and ischemia in chronic total occlusions: A stress-CMR study

BACKGROUND

Well-developed collaterals are assumed as a marker of viability and ischemia in chronic total occlusions (CTO). We aim to correlate viability and ischemia with collateral presence and extent in CTO patients by cardiac magnetic resonance (CMR).

METHODS

Multicentre study of 150 CTO patients undergoing stress-CMR, including adenosine if normal systolic function, high-dose-dobutamine for patients with akinetic/>2 hypokinetic segments and EF ≥35%, otherwise low-dose-dobutamine (LDD); all patients underwent late gadolinium enhancement (LGE) imaging. Viability was defined as mean LGE transmurality ≤50% for adenosine, as functional improvement for dobutamine-stress-test, ischemia as ≥1.5 segments with perfusion defects outside the scar zone.

RESULTS

Rentrop 3/CC 2 defined well-developed (WD, n = 74) vs poorly-developed collaterals (PD, n = 76). Viability was equally prevalent in WD vs PD: normo-functional myocardium with ≤50% LGE in 52% vs 58% segments, p = 0.76, functional improvement by LDD in 48% vs 52%, p = 0.12. Segments with none, 1-25%,26-50%,51-75% LGE showed viability by LDD in 90%,84%,81%,61% of cases, whilst in 12% if 76-100% LGE (p < 0.01). There was no difference in WD vs PD for ischemia presence (74% vs 75%, p = 0.99) and extent (2.7 vs 2.8 segments, p = 0.77).

CONCLUSIONS

In a large cohort of CTO patients, presence and extent of collaterals did not predict viability and ischemia by stress-CMR. Scar extent up to 75% LGE was still associated with viability, whereas ischemia was undetectable in 25% of patients, suggesting that the assessment of CTO patients with CMR would lead to a more comprehensive evaluation of viability and ischemia to guide revascularization.

Clinical application of CMR in cardiomyopathies: evolving concepts and techniques : A position paper of myocardial and pericardial diseases and cardiac magnetic resonance working groups of Italian society of cardiology

Cardiac magnetic resonance (CMR) has become an essential tool for the evaluation of patients affected or at risk of developing cardiomyopathies (CMPs). In fact, CMR not only provides precise data on cardiac volumes, wall thickness, mass and systolic function but it also a non-invasive characterization of myocardial tissue, thus helping the early diagnosis and the precise phenotyping of the different CMPs, which is essential for early and individualized treatment of patients. Furthermore, several CMR characteristics, such as the presence of extensive LGE or abnormal mapping values, are emerging as prognostic markers, therefore helping to define patients' risk. Lastly new experimental CMR techniques are under investigation and might contribute to widen our knowledge in the field of CMPs. In this perspective, CMR appears an essential tool to be systematically applied in the diagnostic and prognostic work-up of CMPs in clinical practice. This review provides a deep overview of clinical applicability of standard and emerging CMR techniques in the management of CMPs.

Cardiac magnetic resonance predictors of left ventricular remodelling following acute ST elevation myocardial infarction: The VavirimS study

BACKGROUND

Left ventricular (LV) remodelling (REM) ensuing after ST-elevation myocardial infarction (STEMI), has typically been studied by echocardiography, which has limitations, or cardiac magnetic resonance (CMR) in early phase that may overestimate infarct size (IS) due to tissue edema and stunning. This prospective, multicenter study investigated LV-REM performing CMR in the subacute phase, and 6 months after STEMI.

METHODS AND RESULTS

patients with first STEMI undergoing successful primary angioplasty were consecutively enrolled. CMR was done at 30-days and 6-months. Primary endpoint was prevalence at 6 months of LV-REM [≥12% increase in LV end-diastolic volume index (LV-REMEDV)]; LV-REM by end-systolic volume index increase ≥12% (LV-REMESV) was also calculated. Of 325 patients enrolled, 193 with a full set of research-quality CMR images were analyzed. LV-REMEDV and LV-REMESV were present in 36/193 (19%) and 34/193 (18%) patients, respectively. At follow up, LV ejection fraction (EF) improved in patients with or without LV-REMEDV, whilst it decreased in those with LV-REMESV (p < 0.001 for interaction). Considering predictors of LV-REM, IS in the highest tertile was clearly separated from the two lower tertiles. In LV-REMEDV, the highest tertile was associated with significantly higher LV-EDV, LV-ESV, and lower EF.

CONCLUSIONS

In a contemporary cohort of STEMI patients studied by CMR, prevalence of LV-REMEDV was lower than previously reported. Importantly, our data indicate that LV-REMEDV might not be "adverse" per se, but rather "compensatory", being associated with LV-EF improvement at follow-up. Conversely, LV-REMESV might be an "adverse" phenomenon associated with decreased LV-EF, driven by IS.

Myocardial Fibrosis at Cardiac MRI Helps Predict Adverse Clinical Outcome in Patients with Mitral Valve Prolapse

Background Patients with mitral valve prolapse (MVP) may develop adverse outcomes even in the absence of mitral regurgitation or left ventricular (LV) dysfunction. Purpose To investigate the prognostic value of mitral annulus disjunction (MAD) and myocardial fibrosis at late gadolinium enhancement (LGE) cardiac MRI in patients with MVP without moderate-to-severe mitral regurgitation or LV dysfunction. Materials and Methods In this longitudinal retrospective study, 118 144 cardiac MRI studies were evaluated between October 2007 and June 2020 at 15 European tertiary medical centers. Follow-up was from the date of cardiac MRI examination to June 2020; the minimum and maximum follow-up intervals were 6 months and 156 months, respectively. Patients were excluded if at least one of the following conditions was present: cardiomyopathy, LV ejection fraction less than 40%, ischemic heart disease, congenital heart disease, inflammatory heart disease, moderate or worse mitral regurgitation, participation in competitive sport, or electrocardiogram suggestive of channelopathies. In the remainder, cardiac MRI studies were reanalyzed, and patients were included if they were aged 18 years or older, MVP was diagnosed at cardiac MRI, and clinical information and electrocardiogram monitoring were available within 3 months from cardiac MRI examination. The end point was a composite of adverse outcomes: sustained ventricular tachycardia (VT), sudden cardiac death (SCD), or unexplained syncope. Multivariable Cox regression analysis was performed. Results A total of 474 patients (mean age, 47 years ± 16 [SD]; 244 women) were included. Over a median follow-up of 3.3 years, 18 patients (4%) reached the study end point. LGE presence (hazard ratio, 4.2 [95% CI: 1.5, 11.9]; P = .006) and extent (hazard ratio, 1.2 per 1% increase [95% CI: 1.1, 1.4]; P = .006), but not MAD presence (P = .89), were associated with clinical outcome. LGE presence had incremental prognostic value over MVP severity and sustained VT and aborted SCD at baseline (area under the receiver operating characteristic curve, 0.70 vs 0.62; P = .03). Conclusion In contrast to mitral annulus disjunction, myocardial fibrosis determined according to late gadolinium enhancement at cardiac MRI was associated with adverse outcome in patients with mitral valve prolapse without moderate-to-severe mitral regurgitation or left ventricular dysfunction. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Gerber in this issue.

Acute clinical presentation of nonischemic cardiomyopathies: early detection by cardiovascular magnetic resonance

Nonischemic cardiomyopathies include a wide range of dilated, hypertrophic and arrhythmogenic heart muscle disorders, not explained by coronary artery disease, hypertension, valvular or congenital heart disease. Advances in medical treatments and the availability of implantable cardioverter defibrillators to prevent sudden cardiac death have allowed a substantial increase in the survival of affected individuals, thus making early diagnosis and tailored treatment mandatory. The characterization of cardiomyopathies has received a great boost from the recent advances in cardiovascular magnetic resonance (CMR) imaging, which, to date, represents the gold standard for noninvasive assessment of cardiac morphology, function and myocardial tissue changes. An acute clinical presentation has been reported in a nonnegligible proportion of patients with nonischemic cardiomyopathies, usually complaining of acute chest pain, worsening dyspnoea or palpitations; 'hot phases' of cardiomyopathies are characterized by a dynamic rise in high-sensitivity troponin, myocardial oedema on CMR, arrhythmic instability, and by an increased long-term risk of adverse remodelling, progression of myocardial fibrosis, heart failure and malignant ventricular arrhythmias. Prompt recognition of 'hot phases' of nonischemic cardiomyopathies is of utmost importance to start an early, individualized treatment in these high-risk patients. On the one hand, CMR represents the gold standard imaging technique to detect early and typical signs of ongoing myocardial remodelling in patients presenting with a 'hot phase' nonischemic cardiomyopathy, including myocardial oedema, perfusion abnormalities and pathological mapping values. On the other hand, CMR allows the differential diagnosis of other acute heart conditions, such as acute coronary syndromes, takotsubo syndrome, myocarditis, pericarditis and sarcoidosis. This review provides a deep overview of standard and novel CMR techniques to detect 'hot phases' of cardiomyopathies, as well as their clinical and prognostic utility.

Cardiovascular magnetic resonance in light-chain amyloidosis to guide treatment

AIMS

To assess the ability of cardiovascular magnetic resonance (CMR) to (i) measure changes in response to chemotherapy; (ii) assess the correlation between haematological response and changes in extracellular volume (ECV); and (iii) assess the association between changes in ECV and prognosis over and above existing predictors.

METHODS AND RESULTS

In total, 176 patients with cardiac AL amyloidosis were assessed using serial N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiography, free light chains and CMR with T1 and ECV mapping at diagnosis and subsequently 6, 12, and 24 months after starting chemotherapy. Haematological response was graded as complete response (CR), very good partial response (VGPR), partial response (PR), or no response (NR). CMR response was graded by changes in ECV as progression (≥0.05 increase), stable (<0.05 change), or regression (≥0.05 decrease). At 6 months, CMR regression was observed in 3% (all CR/VGPR) and CMR progression in 32% (61% in PR/NR; 39% CR/VGPR). After 1 year, 22% had regression (all CR/VGPR), and 22% had progression (63% in PR/NR; 37% CR/VGPR). At 2 years, 38% had regression (all CR/VGPR), and 14% had progression (80% in PR/NR; 20% CR/VGPR). Thirty-six (25%) patients died during follow-up (40 ± 15 months); CMR response at 6 months predicted death (progression hazard ratio 3.82; 95% confidence interval 1.95-7.49; P < 0.001) and remained prognostic after adjusting for haematological response, NT-proBNP and longitudinal strain (P < 0.01).

CONCLUSIONS

Cardiac amyloid deposits frequently regress following chemotherapy, but only in patients who achieve CR or VGPR. Changes in ECV predict outcome after adjusting for known predictors.

Cardiac magnetic resonance feature-tracking analysis of left atrial volumes and function in standard vs left-atrial focused images

Background

Left atrial (LA) volume and function have shown prognostic value in several cardiac conditions. Routine cardiac magnetic resonance (CMR) evaluation of the LA is obtained from standard 2- and 4-chamber long-axis cine images focused on the left ventricle. Previous echocardiographic data showed that LA-focused apical views provide a more accurate estimation of LA maximum volume, as compared to standard apical images. CMR LA-focused imaging could improve the accuracy of LA morpho-functional analysis. CMR feature-tracking (CMR-FT) analysis is emerging as a feasible semi-automatic tool for the evaluation of LA volumes and function.

Purpose

To investigate the potential of LA-focused CMR cine images using LA CMR-FT analysis.

Methods

100 consecutive patients clinically referred to CMR were included in this prospective, observational, multicenter study. LA volumes (LAVmax, LAVmin), emptying fraction (EF), atrial strain reservoir (ɛs), conduit (ɛe), booster (ɛa) and strain rate reservoir (SRɛs) were calculated by CMR-FT analysis on both standard and LA-focused 2- and 4-chamber long-axis cine images. Manual segmentation of a short-axis cine stack covering the LA was used as the reference method (RefMeth) for LA volumes and EF.

Results

In comparison to the RefMeth, the standard acquisitions underestimated LA volumes (LAVmax: bias = −8ml, LOA = +20, −35ml; LAVmin: bias = −6 ml, LOA = +15, −27ml) and slightly overestimated EF (bias = +3%, LOA = +17, −11%). Conversely, LA-focused images provided a more accurate estimation (LAV max bias = −1ml, LOA = +11, −9ml; LAV min bias = −2ml, LOA = +12, −7ml) and EF (bias = −2%, LOA = +9, −12%). All three LA strain (εs: bias 7%, LOA = 25, −11%; εe: bias 4%, LOA = 15, −8%; εa: bias 3%, LOA = 14, −8%) and SRεs (bias 0.2 s–1, LOA = 1.13, −0.7 s–1) were significantly higher in standard vs LA-focused images (all p&lt;0.001).

Conclusions

Assessment of LA volumes using CMR-FT applied to dedicated LA-focused long-axis cine images is more accurate than the use of standard acquisitions. LA strain and SRɛs obtained from LA-focused images are significantly lower than those obtained from standard LA acquisitions, possibly due to the inclusion in LA-focused images of LA posterior wall, where pulmonary veins convey and atrial deformation is blunted.

Funding Acknowledgement

Type of funding sources: None.

[Spontaneous resolution of pericardial cyst: a complex case report]

Pericardial cysts are rare mediastinal abnormalities, generally benign, discovered most often incidentally in the course of diagnostic investigations involving the cardiac profile. They have an incidence of 1 case in 100 000 and are mostly located at the right cardiophrenic angle. Spontaneous resolution of cysts is even rarer. We describe an intricate case report in which the cyst was discovered incidentally and was no longer detected at cardiac magnetic resonance performed 7 years after the first diagnosis. The presence of an asymptomatic pericardial cyst should be regularly followed up over time for the potential risks of complications related to its growth but also because over time, although rarely, it may no longer be detected as in the case presented.

Myocardial infarction with non-obstructive disease and anomalous coronary origin: look for the common in the uncommon

Management of congenital coronary artery anomalies (CAA) is not standardized due to the variety of conditions included and their rare prevalence. Detection of CAA during myocardial infarction with non-obstructive coronary arteries (MINOCA) may induce clinicians to address the patient for surgery as CAA is not included in any algorithm^1,2 for the management of MINOCA and American Association for Thoracic Surgery evidence-based guidelines suggest surgical repair for patients with anomalous aortic origin of a coronary artery and symptoms compatible with myocardial ischaemia.³ We present the case of a 35-year-old man with an anomalous origin of left coronary artery from right Valsalva sinus with pre-pulmonic course detected during urgent coronary angiography for suspected myocardial infarction. Stress cardiac magnetic resonance did not show signs of ischaemia at high-dose dobutamine but did reveal a recent myocarditis. This clinical case highlights the need for accurate risk stratification in CAA especially when confounding clinical scenarios co-exist.

Association of Myocardial Fibrosis and Stroke Volume by Cardiovascular Magnetic Resonance in Patients With Severe Aortic Stenosis With Outcome After Valve Replacement: The British Society of Cardiovascular Magnetic Resonance AS700 Study

Importance

Low-flow severe aortic stenosis (AS) has higher mortality than severe AS with normal flow. The conventional definition of low-flow AS is an indexed stroke volume (SVi) by echocardiography less than 35 mL/m2. Cardiovascular magnetic resonance (CMR) is the reference standard for quantifying left ventricular volumes and function from which SVi by CMR can be derived.

Objective

To determine the association of left ventricular SVi by CMR with myocardial remodeling and survival among patients with severe AS after valve replacement.

Design, Setting, and Participants

This multicenter longitudinal cohort study was conducted between January 2003 and May 2015 across 6 UK cardiothoracic centers. Patients with severe AS listed for either surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) were included. Patients underwent preprocedural echocardiography and CMR. Patients were stratified by echocardiography-derived aortic valve mean and/or peak gradient and SVi by CMR into 4 AS endotypes: low-flow, low-gradient AS; low-flow, high-gradient AS; normal-flow, low-gradient AS; and normal-flow, high-gradient AS. Patients were observed for a median of 3.6 years. Data were analyzed from September to November 2021.

Exposures

SAVR or TAVR.

Main Outcomes and Measures

All-cause and cardiovascular (CV) mortality after aortic valve intervention.

Results

Of 674 included patients, 425 (63.1%) were male, and the median (IQR) age was 75 (66-80) years. The median (IQR) aortic valve area index was 0.4 (0.3-0.4) cm2/m2. Patients with low-flow AS endotypes (low gradient and high gradient) had lower left ventricular ejection fraction, mass, and wall thickness and increased all-cause and CV mortality than patients with normal-flow AS (all-cause mortality: hazard ratio [HR], 2.08; 95% CI, 1.37-3.14; P < .001; CV mortality: HR, 3.06; 95% CI, 1.79-5.25; P < .001). CV mortality was independently associated with lower SVi (HR, 1.64; 95% CI, 1.08-2.50; P = .04), age (HR, 2.54; 95% CI, 1.29-5.01; P = .001), and higher quantity of late gadolinium enhancement (HR, 2.93; 95% CI, 1.68-5.09; P < .001). CV mortality hazard increased more rapidly in those with an SVI less than 45 mL/m2. SVi by CMR was independently associated with age, atrial fibrillation, focal scar (by late gadolinium enhancement), and parameters of cardiac remodeling (left ventricular mass and left atrial volume).

Conclusions and Relevance

In this cohort study, SVi by CMR was associated with CV mortality after aortic valve replacement, independent of age, focal scar, and ejection fraction. The unique capability of CMR to quantify myocardial scar, combined with other prognostically important imaging biomarkers, such as SVi by CMR, may enable comprehensive stratification of postoperative risk in patients with severe symptomatic AS.

Comparison of Four-Dimensional Magnetic Resonance Imaging Analysis of Left Ventricular Fluid Dynamics and Energetics in Ischemic and Restrictive Cardiomyopathies

Background

Time‐resolved three‐directional velocity‐encoded (4D flow) magnetic resonance imaging (MRI) enables the quantification of left ventricular (LV) intracavitary fluid dynamics and energetics, providing mechanistic insight into LV dysfunctions. Before becoming a support to diagnosis and patient stratification, this analysis should prove capable of discriminating between clearly different LV derangements.

Purpose

To investigate the potential of 4D flow in identifying fluid dynamic and energetics derangements in ischemic and restrictive LV cardiomyopathies.

Study Type

Prospective observational study.

Population

Ten patients with post‐ischemic cardiomyopathy (ICM), 10 patients with cardiac light‐chain cardiac amyloidosis (AL‐CA), and 10 healthy controls were included.

Field Strength/Sequence

1.5 T/balanced steady‐state free precession cine and 4D flow sequences.

Assessment

Flow was divided into four components: direct flow (DF), retained inflow, delayed ejection flow, and residual volume (RV). Demographics, LV morphology, flow components, global and regional energetics (volume‐normalized kinetic energy [KE_V] and viscous energy loss [EL_V]), and pressure‐derived hemodynamic force (HDF) were compared between the three groups.

Statistical Tests

Intergroup differences in flow components were tested by one‐way analysis of variance (ANOVA); differences in energetic variables and peak HDF were tested by two‐way ANOVA. A P‐value of <0.05 was considered significant.

Results

ICM patients exhibited the following statistically significant alterations vs. controls: reduced KE_V, mostly in the basal region, in systole (−44%) and in diastole (−37%); altered flow components, with reduced DF (−33%) and increased RV (+26%); and reduced basal–apical HDF component on average by 63% at peak systole. AL‐CA patients exhibited the following alterations vs. controls: significantly reduced KE_V at the E‐wave peak in the basal segment (−34%); albeit nonstatistically significant, increased peaks and altered time‐course of the HDF basal–apical component in diastole and slightly reduced HDF components in systole.

Data Conclusion

The analysis of multiple 4D flow‐derived parameters highlighted fluid dynamic alterations associated with systolic and diastolic dysfunctions in ICM and AL‐CA patients, respectively.

Level of Evidence

2

Technical Efficacy Stage

3

Arrhythmic manifestation in β-thalassemia cardiomyopathy: a complex management

A young male with β-thalassemia major was implanted with a single-chamber Implantable cardioverter-defibrillator (ICD) for a cardiac arrest due to ventricular fibrillation. He received multiple inappropriate shocks due to atrioventricular nodal re-entrant tachycardia (AVNRT) treated with radiofrequency catheter ablation and then to high-rate atrial tachycardia refractory to amiodarone and not inducible during electrophysiological study. He refused empirical pulmonary vein isolation. Upgrading to biventricular ICD and performing atrioventricular node ablation avoided further inappropriate shocks.

Brugada Syndrome: New Insights From Cardiac Magnetic Resonance and Electroanatomical Imaging

BACKGROUND

Brugada syndrome (BrS) is considered a purely electrical disease with variable electrical substrates. Variable rates of mechanical abnormalities have been also reported. Whether exists a link between electrical and mechanical abnormalities has never been previously explored. This investigational physiopathological study aimed to determine the relationship between the substrate size/location, as exposed by ajmaline provocation, and the severity of mechanical abnormalities, as assessed by cardiac magnetic resonance in patients with BrS.

METHODS

Twenty-four consecutive high-risk patients with BrS (mean age, 38±11 years, 17 males), presenting with malignant syncope and documented polymorphic ventricular tachycardia/ventricular fibrillation, and candidate to implantable cardioverter defibrillator implantation, underwent cardiac magnetic resonance and electroanatomic maps. During each examination, ajmaline test (1 mg/kg over 5 minutes) was performed. Cardiac magnetic resonance findings were compared with 24 age, sex, and body surface area-matched controls. In patients with BrS, the correlation between the electrical substrate extent and right ventricular regional mechanical abnormalities before/after ajmaline challenge was analyzed.

RESULTS

After ajmaline, patients with BrS showed a reduction of right ventricular (RV) ejection fraction (P<0.001), associated with decreased transversal displacement (U, P<0.001) and longitudinal strain (ε, P<0.001) localized at RV outflow tract. In patients with BrS significant preajmaline/postajmaline changes of transversal displacement (ΔU, P<0.001) and longitudinal strain (Δε, P<0.001) were found. In the control group, no mechanical changes were observed after ajmaline. The electrical substrate consistently increased after ajmaline from 1.7±2.8 cm² to 14.2±7.3 cm² (P<0.001), extending from the RV outflow tract to the neighboring segments of the RV anterior wall. Postajmaline RV ejection fraction inversely correlated with postajmaline substrate extent (r=-0.830, P<0.001). In patients with BrS and normal controls, cardiac magnetic resonance detected neither myocardial fibrosis nor RV outflow tract morphological abnormalities.

CONCLUSIONS

BrS is a dynamic RV electromechanical disease, where functional abnormalities correlate with the maximal extent of the substrate size. These findings open new lights on the physiopathology of the disease. Registration: URL: https://clinicaltrial.gov; Unique identifier: NCT03524079.

CarDiac magnEtic Resonance for prophylactic Implantable-cardioVerter defibrillAtor ThErapy in Non-Ischaemic dilated CardioMyopathy: an international Registry

AIMS

The aim of this registry was to evaluate the additional prognostic value of a composite cardiac magnetic resonance (CMR)-based risk score over standard-of-care (SOC) evaluation in a large cohort of consecutive unselected non-ischaemic cardiomyopathy (NICM) patients.

METHODS AND RESULTS

In the DERIVATE registry (www.clinicaltrials.gov/registration: RCT#NCT03352648), 1000 (derivation cohort) and 508 (validation cohort) NICM patients with chronic heart failure (HF) and left ventricular ejection fraction <50% were included. All-cause mortality and major adverse arrhythmic cardiac events (MAACE) were the primary and secondary endpoints, respectively. During a median follow-up of 959 days, all-cause mortality and MAACE occurred in 72 (7%) and 93 (9%) patients, respectively. Age and >3 segments with midwall fibrosis on late gadolinium enhancement (LGE) were the only independent predictors of all-cause mortality (HR: 1.036, 95% CI: 1.0117-1.056, P < 0.001 and HR: 2.077, 95% CI: 1.211-3.562, P = 0.008, respectively). For MAACE, the independent predictors were male gender, left ventricular end-diastolic volume index by CMR (CMR-LVEDVi), and >3 segments with midwall fibrosis on LGE (HR: 2.131, 95% CI: 1.231-3.690, P = 0.007; HR: 3.161, 95% CI: 1.750-5.709, P < 0.001; and HR: 1.693, 95% CI: 1.084-2.644, P = 0.021, respectively). A composite clinical and CMR-based risk score provided a net reclassification improvement of 63.7% (P < 0.001) for MAACE occurrence when added to the model based on SOC evaluation. These findings were confirmed in the validation cohort.

CONCLUSION

In a large multicentre, multivendor cohort registry reflecting daily clinical practice in NICM work-up, a composite clinical and CMR-based risk score provides incremental prognostic value beyond SOC evaluation, which may have impact on the indication of implantable cardioverter-defibrillator implantation.

ECG-based score estimates the probability to detect Fabry Disease cardiac involvement

OBJECTIVES

To elaborate an ECG-based nomogram estimating the probability to detect cardiac involvement by cardiac magnetic resonance (CMR) in Fabry Disease (FD).

METHODS

119 FD patients and 26 healthy controls underwent ECG and CMR. Test (n = 88, 60%) and validation cohorts (n = 57, 40%) were randomly derived. Cardiac involvement was defined as the presence of low myocardial T1 value, a CMR-surrogate of myocardial glycosphingolipid storage. ECG changes associated with low T1 value were identified in the test cohort, included in the nomogram and then tested in the validation cohort.

RESULTS

Sokolow-Lyon index (AUC = 0.769), ratio between P-wave and PR-segment durations (Pwave/PRsegment) (AUC = 0.778), QRS duration (AUC = 0.703), QT (AUC = 0.769) duration were independently associated with the presence of low T1 on CMR at multivariate analysis. An ECG-based nomogram including these four parameters was accurate in identifying patients with CMR evidence of glycosphingolipid storage (c-index of the derived-nomogram = 0.90 in the test group; 0.81 in the validation group).

CONCLUSION

We propose a practical ECG-based nomogram accurately estimating the probability to detect low T1 values by CMR in FD patients. The application of this tool in clinical practice could improve early detection of FD cardiac involvement.

Left atrial morpho-functional changes in hypertrophic cardiomyopathy and Fabry disease: a CMR-feature tracking study

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular (LV) diastolic dysfunction (DD) is a hallmark of hypertrophic cardiomyopathy (HCM) and its phenocopies, such as Fabry disease (FD). Together with left atrial (LA) size, LA function is emerging as a sensitive marker of the adaptive changes to backward transmission of LV cardiac filling pressure, thus implementing DD assessment. Additionally, both HCM and FD are characterized by a primitive atrial myopathy, but LA morpho-functional changes in HCM and FD have never been directly compared. More recently, LA strain by Cardiovascular Magnetic Resonance Feature Tracking (CMR-FT) has been demonstrated to be a feasible and reproducible tool to explore LA function.

Purpose

To compare LA morpho-functional changes in HCM and FD and to explore their correlation with tissue alterations.

Methods

15 HCM and 15 sex-, age- and LV mass index-matched FD patients underwent CMR (Magnetom Aera 1.5T, Siemens) and Doppler Echocardiography for LV diastolic function assessment (E/e’ and DD grading from 0 to 3). LA phasic function was evaluated by CMR-FT strain (Qstrain Medis). The software output included passive (εe, conduit function), active (εa, booster pump function) and total strain (εs, reservoir function), along with LA volumes and ejection fraction (EF). Late gadolinium enhancement (LGE) was quantified as a percentage of LV mass using the standard deviations (SDs) method (≥ 5 SDs). Interstitial fibrosis was assessed by extracellular volume (ECV) quantification in remote myocardium. All patients were in sinus rhythm.

Results

In the HCM group, the proportion of patients with DD grade 2-3 was only slightly higher than in FD (p 0.26). Accordingly, no significant difference was found in E/e’ value (p 0.78). Compared to FD, HCM patients showed more severe LA morpho-functional changes, including larger LA end-systolic volume (ESV) (113 ± 35 vs 84 ± 23 ml), lower LA EF (37 ± 7 vs 44 ± 9 %) and a greater reduction of εs (-20 ± 5 vs -25 ± 6 %) and εa (-10 ± 4 vs -15 ± 4 %) (all p &lt; 0.05). LV size and function and the burden of fibrosis (LGE quantification and ECV) were comparable between the two groups. Interestingly, in HCM population, unlike in FD, LA morpho-functional measurements significantly correlated with tissue characterization parameters (LA ESV with LGE, r 0.56, p 0.03; εs and εa with ECV, r -0.51, p 0.05 and r -0.59, p 0.02, respectively).

Conclusions

LA morpho-functional alterations are much more severe in HCM compared to FD with similar degree of LV hypertrophy. A more severe atrial myopathy or different mechanisms of atrial damage in the two cardiomyopathies may explain these findings. LA CMR-FT analysis may represent a sensitive tool to discriminate between HCM and FD, although larger studies are needed to confirm this finding and the possible correlation with the occurrence of atrial arrhythmias and thromboembolic risk.

Late gadolinium enhancement predicts adverse clinical outcome in patients with mitral valve prolapse/mitral annulus disjunction

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Mitral vAlve prolapse and disjunction by cardiac maGnetIC resonance (MA-GIC) registry

Backgroung

Mitral valve prolapse (MVP) is 2-3% prevalent in the general population with good prognosis. However, some patients develop complex ventricular arrhythmias (CVAs), sudden cardiac death (SCD), or severe mitral regurgitation (MR). Previous studies suggested that bi-leaflet involvement, mitral annulus disjunction (MAD), and myocardial fibrosis (MF) are associated with adverse outcome. Notwithstanding, these findings were limited to autopsic series or single-centre studies involving highly selected patients. Moreover, MF has been scantly investigated as predictor of clinical outcome.

Purpose

To investigate the prognostic significance of MF in an international multicentre study of MVP patients studied by cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE). 

Methods

From October 2007 to June 2020 patients undergoing LGE-CMR were screened in 14 European centres. Inclusion criteria were: i) age &gt; 18 years; ii) full clinical history and cardiac rhythm monitoring at baseline; iii) MVP (leaflet displacement ≥ 2 mm beyond the annulus). Exclusion criteria were: i) ischemic heart disease; ii) primary cardiomyopathy; iii) inflammatory heart disease; iv) congenital heart diseases; v) moderate-to-severe valvular heart disease. CVAs at the study outset was defined as one of the following: i) ventricular ectopic beats &gt;10000/24h; ii) ≥ 1 episode of non-sustained ventricular tachycardia (VT); iii) sustained VT; iv) aborted SCD. Primary end-point was a composite of SCD, unexplained syncope, and mitral valve repair/replacement. Secondary end-point was a composite of SCD and unexplained syncope. 

Results

Four-hundred-fifty-eight MVP patients were eventually included (46 ± 16 years old, 51% males) of whom 68% had MAD. LGE was detected in 103 (22%) of subjects with mid-wall pattern (46%) in left ventricular (LV) lateral wall (66%) as the most prevalent feature. At baseline, 37% of LGE-positive patients vs. 18% of LGE-negative individuals had CVAs (P &lt; 0.001). SVT and/or aborted SCD were more prevalent in LGE-positive than in LGE-negative patients (9% vs 2%, P &lt; 0.001). By multivariable Cox-regression analysis, LGE presence or extent were strong independent predictors of the primary (HR = 4.02, P = 0.003 and HR = 4.76 per 10% increase, P = 0.032, respectively) and secondary (HR = 5.39, P = 0.008 and HR = 8.78 per 10% increase, P = 0.012, respectively) endpoints after correction for major confounders including LV volumes, left atrial size and MAD presence.

Conlusion

Myocardial fibrosis by LGE is the strongest independent predictor of clinical outcome in MVP. In contrast, MAD per se does not harbinger worse prognosis.

Left atrial strain analysis in hypertensive heart disease and hypertrophic cardiomyopathy by cardiovascular magnetic resonance feature tracking

Funding Acknowledgements

Type of funding sources: None.

Background

Increasing evidence suggests that left atrial (LA) deformation is a sensitive marker of diastolic dysfunction in hypertrophic phenotypes. However, there is little data about the impact of hypertension on LA function; furthermore, LA deformation in hypertensive heart disease (HHD) and hypertrophic cardiomyopathy (HCM) has not been compared yet. 

Purpose

The aim of this study is to compare atrial dimensions and function, evaluated by cardiovascular magnetic resonance feature tracking (CMR-FT) in patients with HHD, HCM and healthy subjects (HS).

Methods

67 patients (20 HHD, 27 HCM, 20 HS) underwent CMR and were included in the study. Patients were matched for age, sex and BSA; HHD and HCM were also comparable for LV mass index and ejection fraction (EF). CMR-FT atrial strain analysis was performed using Qstrain, Medis software to obtain i) LA conduit function, ii) LA booster pump function), iii) LA reservoir function, iv) LA volumes and EF. Tissue Doppler echocardiography was used to assess diastolic function, including E/e’. LA stiffness was calculated as the ratio between E/e’ and LA reservoir.

Both focal and interstitial myocardial fibrosis were assessed with LGE and extracellular volume (ECV) quantification. 

Results

HHD and HCM showed impaired LA reservoir, conduit function and higher LA volumes vs HS (reservoir: 28 ± 11% and 28 ± 13% vs 41 ± 17%; conduit: 13 ± 7% and 13 ± 7% vs 22 ± 11%; LAESV: 76 ± 21 and 87 ± 22 vs 57 ± 19 ml respectively; all p ≤ 0.03).

HHD and HCM were comparable for bi-ventricular morpho-functional parameters and ECV. HHD showed lower E/e’ values (8 ± 2 vs 16 ± 7, p = 0.002) and LA stiffness (0.23 ± 0.3 vs 0.74 ± 0.6, p 0.03), LA dimensions (LA area 13 ± 3 vs 16 ± 3 cm2/m2, p = 0.02 , LAESVi 41 ± 12 vs 48 ± 11 ml/m2, p = 0.05) and LGE extent (1 ± 2% vs 5 ± 5%, p = 0.001) as compared to HCM. Interestingly, HHD revealed a comparable reduced LA reservoir and conduit function (all p = 0.9) vs HCM. 

In HHD patients LA reservoir function was correlated with E/e’ (r -0.8, p = 0.02), but not in HCM. Conversely, LA reservoir function was correlated with LV mass index in HCM (r -0.5, p &lt; 0.01). 

Conclusions

HHD patients showed a similar and significant impairment of LA function, with lower LA dimensions and E/e’ compared to HCM with similar LV mass index and preserved function.

CMR-FT atrial strain analysis could represent a useful tool for HHD management, able to detect diastolic dysfunction (and/or atrial dysfunction) earlier than traditional markers. Further studies are needed to explore the relationship of LA deformation to heart failure symptoms and atrial fibrillation occurrence and potential changes related to response to therapy.

Cardiovascular magnetic resonance: What clinicians should know about safety and contraindications

Cardiovascular magnetic resonance (MR) is a multiparametric, non-ionizing, non-invasive imaging technique, which represents the imaging gold standard to study cardiac anatomy, function and tissue characterization. Faced with a wide range of clinical application, in this review we aim to provide a comprehensive guide for clinicians about MR safety, contraindications and image quality. Starting from the physical interactions of the static magnetic fields, gradients and radiofrequencies with the human body, we will describe the most common metal and electronic devices which are allowed (MR-safe), allowed under limited conditions (MR-conditional) or contraindicated (MR-unsafe). Moreover, some conditions potentially affecting image quality and patient comfort will be mentioned, including arrhythmias, claustrophobia, and poor breath-hold capacity. Finally, we will discuss the pharmacodynamics and pharmacokinetics of current gadolinium-based contrast agents, their contraindications and their potential acute and chronic adverse effects, as well as the safety issue concerning the use of vasodilating/inotropic agents in stress cardiac MR.

4D flow evaluation of blood non-Newtonian behavior in left ventricle flow analysis

Blood is generally modeled as a Newtonian fluid, assuming a standard and constant viscosity; however, this assumption may not hold for the highly pulsatile and recirculating intracavitary flow in the left ventricle (LV), hampering the quantification of fluid dynamic indices of potential clinical relevance. Herein, we investigated the effect of three viscosity models on the patient-specific quantification of LV blood energetics, namely on viscous energy loss (EL), from 4D Flow magnetic resonance imaging: I) Newtonian with standard viscosity (3.7 cP), II) Newtonian with subject-specific hematocrit-dependent viscosity, III) non-Newtonian accounting for the effect of hematocrit and shear rate. Analyses were performed on 5 controls and 5 patients with cardiac light-chain amyloidosis. In Model II, viscosity ranged between 3.0 (-19%) and 4.3 cP (+16%), mildly deviating from the standard value. In the non-Newtonian model, this effect was emphasized: viscosity ranged from 3.2 to 6.0 cP, deviating maximally from the standard value in low shear rate (i.e., <100 s^-1) regions. This effect reflected on EL quantifications: in particular, as compared to Model I, Model III yielded markedly higher EL values (up to +40%) or markedly lower (down to -21%) for subjects with hematocrit higher than 39.5% and lower than 30%, respectively. Accounting for non-Newtonian blood behavior on a patient-specific basis may enhance the accuracy of intracardiac energetics assessment by 4D Flow, which may be explored as non-invasive index to discriminate between healthy and pathologic LV.

Interaction of stroke volume and myocardial phenotype in patients with severe aortic stenosis referred for intervention: outcome data from the BSCMR AS700 study

Funding Acknowledgements

Type of funding sources: None.

onbehalf

The BSCMR Valve Consortium

Background

 Patients with low-flow aortic stenosis (LF-AS) have higher mortality than those with high-flow severe AS.  The conventional echocardiographic definition of LF-AS is an indexed stroke volume (SVi) &lt;35ml/m2. Whether this cut-off translates to cardiac magnetic resonance (CMR), and how CMR SVi associates with myocardial remodelling (volume/function/scar) and survival is unclear.

Purpose

 To determine the association between CMR SVi, myocardial remodelling and survival in severe symptomatic AS. 

Methods

  In a multi-centre longitudinal outcome study of patients with severe AS listed for either surgical (SAVR) or transcatheter aortic valve intervention (TAVI) at six cardiothoracic centres, survival was assessed and stratified by SVi. Patients underwent preprocedural echocardiography and CMR between January 2003 and May 2015.  Standardised core-lab analyses on pre-procedural CMR for biventricular volumes, function and scar quantification were performed. All-cause and cardiovascular mortality were tracked for a minimum of two years after AVR.

Results

 A total of 674 patients with severe AS (age 75 ± 14years; 63% male, aortic valve area 0.4 ± 0.1 cm2/m2) were included.  Patients with low SVi by CMR &lt;35ml/m2 were older and had a greater burden of comorbidities (atrial fibrillation [AF], diabetes, high BMI). Independent predictors of SVi were age, AF, increased left atrial volume, aortic valve regurgitant fraction and left ventricular mass (LV) mass index (by CMR). There was no difference in SVi with choice of intervention (TAVI vs SAVR) or presence of late gadolinium enhancement. In multivariate analysis (Table 1), SVi was associated with cardiovascular mortality in the whole cohort (HR 0.97, 95%CI 0.95-0.99, p = 0.02), and all-cause mortality after TAVI (HR 0.97, 95%CI 0.95-0.99, p = 0.006) but not SAVR (p = 0.6). Adjusted mortality hazard increases below 50ml/m2 and plateaus between 35-40ml/m2 (Figure 1A), adjusted for LGE, STS score (Society of Thoracic Surgery score) and wall thickness.

Conclusion

SVi by CMR is an independent predictor of cardiovascular mortality. Mortality hazard increases progressively below a SVi of 50mL/m2.

Abstract Figure 1

The alcohol-induced cardiomyopathy: A cardiovascular magnetic resonance characterization

BACKGROUND

Alcoholic cardiomyopathy(ACM) is part of the non-ischaemic dilated cardiomyopathy(NI-DCM) spectrum. Little is known about cardiovascular magnetic resonance(CMR) features in ACM patients. The aim of this study is to describe CMR findings and their prognostic impact in ACM patients.

METHODS

Consecutive ACM patients evaluated in five referral CMR centres from January 2005 to December 2018 were enrolled. CMR findings and their prognostic value were compared to idiopathic NI-DCM(iNI-DCM) patients. The main outcome was a composite of death/heart transplantation/life-threatening arrhythmias.

RESULTS

Overall 114 patients (52 with ACM and 62 with iNI-DCM) were included. ACM patients were more often males compared to iNI-DCM (90% vs 64%, respectively, p ≤ 0.001) and were characterized by a more pronounced biventricular adverse remodelling than iNI-DCM, i.e. lower LVEF (31 ± 12% vs 38 ± 11% respectively, p = 0.001) and larger left ventricular end-diastolic volume (116 ± 40 ml/m² vs 67 ± 20 ml/m² respectively, p < 0.001). Similarly to iNI-DCM, late gadolinium enhancement (LGE), mainly midwall, was present in more than 40% of ACM patients but, conversely, it was not associated with adverse outcome(p = 0.15). LGE localization was prevalently septal (87%) in ACM vs lateral in iNI-DCM(p < 0.05). Over a median follow-up of 42 months [Interquartile Range 24-68], adverse outcomes were similar in both groups(p = 0.67).

CONCLUSIONS

ACM represents a specific phenotype of NI-DCM, with severe morpho-functional features at the onset, but similar long-term outcomes compared to iNI-DCM. Despite the presence and pattern of distribution of LGE was comparable, ACM and iNI-DCM showed a different LGE localization, mostly septal in ACM and lateral in iNI-DCM, with different prognostic impact.

Trabecular complexity as an early marker of cardiac involvement in Fabry disease

AIMS

Fabry cardiomyopathy is characterized by glycosphingolipid storage and increased myocardial trabeculation has also been demonstrated. This study aimed to explore by cardiac magnetic resonance whether myocardial trabecular complexity, quantified by endocardial border fractal analysis, tracks phenotype evolution in Fabry cardiomyopathy.

METHODS AND RESULTS

Study population included 20 healthy controls (12 males, age 32±9) and 45 Fabry patients divided into three groups: 15 left ventricular hypertrophy (LVH)-negative patients with normal T1 (5 males, age 28±13; Group 1); 15 LVH-negative patients with low T1 (9 males, age 33±9.6; Group 2); 15 LVH-positive patients (11 males, age 53.5±9.6; Group 3). Trabecular fractal dimensions (Dfs) (total, basal, mid-ventricular, and apical) were evaluated on cine images. Total Df was higher in all Fabry groups compared to controls, gradually increasing from controls to Group 3 (1.27±0.02 controls vs. 1.29±0.02 Group 1 vs. 1.30±0.02 Group 2 vs. 1.34±0.02 Group 3; P<0.001). Group 3 showed significantly higher values of all Dfs compared to the other Groups. Both basal and total Dfs were significantly higher in Group 1 compared with controls (basal: 1.30±0.03 vs. 1.26±0.04, P =0.010; total: 1.29±0.02 vs. 1.27±0.02, P=0.044). Total Df showed significant correlations with: (i) T1 value (r=-0.569; P<0.001); (ii) LV mass (r=0.664, P<0.001); (iii) trabecular mass (r=0.676; P <0.001); (iv) Mainz Severity Score Index (r=0.638; P<0.001).

CONCLUSION

Fabry cardiomyopathy is characterized by a progressive increase in Df of endocardial trabeculae together with shortening of T1 values. Myocardial trabeculation is increased before the presence of detectable sphingolipid storage, thus representing an early sign of cardiac involvement.

Right ventricular functional changes detected by CMR during ajmaline challenge in patients with Brugada syndrome

Background

3D echocardiography has recently revealed alterations of right ventricular (RV) function in Brugada syndrome (BrS) during ajmaline challenge (AC). Cardiac magnetic resonance (CMR) is the gold standard for functional and anatomical RV assessment. CMR feature-tracking (FT) analysis is able to detect subtle functional changes in the underlying myocardial substrate.

Purpose

To investigate RV functional changes during AC in BrS patients using CMR-FT analysis.

Methods

24 consecutive BrS and 28 matched controls underwent CMR. CMR protocol included paraxial and parasagittal cine bSSFP sequences, acquired before and 2÷5 minutes after ajmaline infusion (1 mg/kg in 5 minutes), to obtain a comprehensive evaluation of the RV free wall. All patients were closely monitored with ECG. Semi-automatic threshold-based quantification of ventricular volumes, function and mass was performed in QMass. CMR-FT analysis of RV function was performed in QStrain. Values of longitudinal strain (LS) and transverse displacement (TD) of the RV wall before and after AC were compared in BrS patients and in the control group.

Results

AC induced Type 1 ECG pattern in all BrS patients and no ECG changes in controls. In BrS patients TD of the RV free wall was significantly reduced (P≤0.003) at peak ajmaline effect; controls reported sub-millimetric TD changes. LS of the RV wall was significantly impaired in BrS patients (P&lt;0.0001) on both b SSFP sequences; LS remained comparable (P=0.62) in controls on the parasagittal sequence; minor but not negligible (P=0.01) LS changes were noticed on the paraxial stack. (Table 1)

Conclusions

In patients with BrS CMR-FT analysis during AC unveils dysfunctional RV wall mechanics in areas generally associated with abnormal electrical activity.

TD and LS in a Brs patient post AC

Funding Acknowledgement

Type of funding source: None

Quantitative 4D Flow CMR analysis of intracardiac blood flow energetics in ischemic cardiomyopathy patients

Background

Ischemic cardiomyopathy (ICM) is often associated with negative LV remodelling after myocardial infarction, sometimes resulting in impaired LV function and dilation (iDCM). 4D Flow CMR has been recently exploited to assess intracardiac hemodynamic changes in presence of LV remodelling.

Purpose

To quantify 4D Flow intracardiac kinetic energy (KE) and viscous energy loss (EL) and investigate their relation with LV dysfunction and remodelling.

Methods

Patients with prior anterior myocardial infarction underwent a CMR study with 4D Flow sequences acquisition; they were divided into ICM (n=10) and iDCM (n=10, EDV&gt;208 ml and EF&lt;40%). 10 controls were used for comparison. LV was semi-automatically segmented using short axis CMR stacks and co-registered with 4D Flow. Global KE and EL were computed over the cardiac cycle. NT-proBNP measurements were correlated with average and peak values, during systole and diastole.

Results

Both LV volume and EF significantly differ (P&lt;0.0001) between iDCM (EDV=294±56 ml, EF=24±8%), ICM (EDV=181±32 ml, EF=34±6%) and controls (EDV=124±29 ml, EF=72±5%). If compared to controls, both ICM and iDCM showed significantly lower KE (P≤0.0008); though lower than controls, EL was higher in iDCM than ICM. Within the iDCM subgroup, diastolic mean KE and peak EL reported good inverse correlation with NT-proBNP (r=−0.75 and r=−0.69, respectively). EL indexed (ELI) to average KE during systole was higher in the entire ischemic group as compared to controls (ELI(ischemic) = 0.17 vs. ELI(controls) = 0.10, P=0.0054).

Conclusions

4D Flow analyses effectively mapped post-ischemic LV energetic changes, highlighting the disproportionate intraventricular EL relative to produced KE; preliminary good correlation between LV energetic changes and NT-proBNP will deserve further investigation in order to contribute to early detection of heart failure.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Italian Ministry of Health

Increased remote extracellular volume measured by CMR T1 mapping allows early identification of left atrial dysfunction in hypertrophic cardiomyopathy

Background

Myocardial fibrosis is a hallmark of hypertrophic cardiomyopathy (HCM). Cardiac magnetic resonance (CMR) detects replacement fibrosis (RF) through late gadolinium enhancement (LGE) and interstitial fibrosis (IF) in apparently unscarred myocardium by T1 mapping-derived increased extracellular volume (ECV). Differently from LGE, to date only few small studies have explored the clinical significance of IF in HCM and a correlation between IF and diastolic dysfunction (DD) has been proposed. However, DD detection is challenging in this population since the accuracy of standard echocardiographic parameters is controversial, especially in presence of left ventricular outflow tract obstruction (LVOTO). Left atrial (LA) dysfunction is associated with high left ventricular (LV) filling pressures and may represent an early marker of DD in HCM.

Purpose

To explore the correlation between IF and LA dysfunction in HCM patients with preserved systolic function.

Methods

93 consecutive HCM patients with preserved EF underwent a standard CMR scan. Semi-automatic threshold-based quantification of ventricular volumes, function and mass was performed. LA volumes (LAV) and function were evaluated by CMR feature-tracking (FT) analysis. The three atrial phasic functions were analyzed: (i) passive strain (εe), (ii) active strain (εa) and (iii) total strain (εs). LGE was quantified using the standard deviations (SDs) method (≥4 SDs). IF was assessed by T1 mapping-derived ECV quantification in remote myocardium (r-ECV). A matched group of 15 healthy subjects (HS) served as controls.

Results

Compared to HS, HCM patients showed increased LAV (LAV max: HS 39±9ml, HCM 59±20 ml; LAV min: HS 16±4 ml, HCM 34±17 ml; p&lt;0.001), reduced LA EF (HS 61±3%, HCM 45±12%, p&lt;0.001), impaired εs (HS 40±7%, HCM 29±11%, p&lt;0.001) and εe (HS 26±7%, HCM 15±7%, p&lt;0.001). No differences in εa were observed (HS 13±4%, HCM 14±7%, p 0.56). HCM patients were divided into 2 groups according to the presence of IF, defined as r-ECV values ≥29%. The two ECV groups did not differ in terms of LV EF, LA EF, LAV, LA area, E/E', LGE, LV mass, maximal wall thickness and LVOTO (all p&gt;0.05). HCM patients with increased r-ECV showed significantly impaired LA function in terms of all three strain parameters vs. normal r-ECV group (HCM r-ECV &lt;29%: εs 31±12%, εe15±7%, εa 15±5%; HCM r-ECV≥29%: εs 24±7%, εe 12±4%, εa 12±5%; all p&lt;0.05).

Conclusions

In HCM patients increased r-ECV correlates with LA dysfunction, hinting towards a possible role for IF in determining altered LV relaxation and DD.

LA strain in controls and HCM ECV groups

Funding Acknowledgement

Type of funding source: None

Anomalous aortic origin of coronary artery biomechanical modeling: Toward clinical application

OBJECTIVES

Anomalous aortic origin of the coronary artery can be associated with sudden cardiac death and ischemic events. Anatomic static characteristics mainly dictated surgical indications, although adverse events are usually related to dynamic physical effort. We developed a computational model able to simulate anomalous coronary behavior, and we aimed to assess its clinical applicability and to investigate coronary characteristics at increasing loading stress conditions.

METHODS

We selected 5 patients with anomalous aortic origin of the coronary artery and 5 control subjects. For each of them, we construct a 3-dimensional model resembling the aortic root and coronary arteries based on 25 parameters obtained from computed tomography. Structural finite element analysis simulations were run to simulate pressure increasing in the aortic root during exercise (+40 mm Hg, +100 mm Hg with respect baseline condition, assumed at 80 mm Hg) and investigate coronary lumen characteristics.

RESULTS

The 25 parameters were obtainable in all subjects with a consistent interobserver agreement. In control subjects, the right coronary artery had a more significant lumen expansion at loading conditions compared with anomalous aortic origin of coronary artery (6%-19.2% vs 1.8%-8.1%, P = .008), which also showed an inability to expand within the intramural segment.

CONCLUSIONS

The proposed anomalous aortic origin of coronary artery model is able to represent the pathogenic disease mechanism after being populated with patient-specific data. It can assess the impaired expansion of anomalous right coronary at loading conditions, a process that cannot be quantified in any clinical set-up. This first clinical application showed promising results on quantifying pathological behavior, potentially helping in patient-specific risk stratification.

Predictors of Clinical Evolution in Prehypertrophic Fabry Disease

BACKGROUND

In prehypertrophic Fabry disease, low myocardial T1 values, reflecting sphingolipid storage, are associated with early structural and ECG changes. The correlations between T1 values and functional parameters have not been explored. Furthermore, the potential prognostic role of T1 in predicting disease worsening is still unknown.

METHODS

ECG, 2D echocardiography, cardiopulmonary test, and cardiac magnetic resonance were performed in 44 Fabry patients without left ventricular hypertrophy (35.7±14.5 years, 68.2% females). After a 12-month follow-up, clinical stability was evaluated using Fabry Stabilization Index.

RESULTS

At baseline, T1 values showed a negative correlation with left ventricular mass ( r=-0.79; P<0.0001), maximum wall thickness ( r=-0.79; P<0.0001), Sokolow-Lyon Index ( r=-0.54; P<0.0001), left atrial volume ( r=-0.49; P<0.0002), and Mainz Severity Score Index ( r=-0.61; P<0.0001). No significant differences in systo-diastolic function and exercise capacity were observed comparing normal and low T1 Fabry patients. Arrhythmias were reported in 2 females with low T1 and late gadolinium enhancement. Five patients (40.0±12.4 years, 2 females) showed clinical worsening (Fabry Stabilization Index >20%) at follow-up. Higher left ventricular wall thickness (odds ratio, 2.61; CI, 1.04-6.57; P=0.04), left atrial volume (odds ratio, 1.24; CI, 1.02-1.51; P=0.03), and lower T1 values (odds ratio, 0.98; CI, 0.96-0.99; P=0.03) at baseline were independently associated with clinical worsening at follow-up.

CONCLUSIONS

In prehypertrophic Fabry disease, low T1 values correlate with early electrocardiographic, morphological cardiac changes, and worsening of global disease severity but are not associated with functional abnormalities. The presence of low T1 values is a risk factor for disease worsening, thus representing a potential new tool in prognostic stratification and therapeutic approach.

Reliability of single breath hold three-dimensional cine kat-ARC for the assessment of biventricular dimensions and function

PURPOSE

To assess the accuracy and reproducibility of 3D-cine k-adaptative-t-autocalibrating reconstruction for cartesian sampling (3D cine kat-ARC) for quantification of biventricular volumes, ejection fraction and LV mass in clinical practice.

METHOD

74 patients underwent cardiac magnetic resonance for clinical indications. In the whole population 3D cine kat-ARC and 2D cine bSSFP images were acquired on short axis view. Subsequently, the population was divided in three subgroups (dilated, hypetrophic, other phenotypes). Two experienced observers performed analysis of volumes, biventricular function and left ventricular mass in the overall population and subgroups using an off-line workstation. Statistical analysis was performed using Student's t-test, linear regression and Bland-Altman plot, correlation coefficient η2 and the intraclass correlation coefficient (ICC). A cut-off value of p < 0.05 was considered statistically significant.

RESULTS

Biventricular volumes, function and left ventricular mass evaluated with 3D cine kat-ARC sequences did not show any significant difference compared to 2D bSSFP sequences in the overall population (p > 0.05). Bland-Altman analysis showed limited bias and narrow limits of the agreement for all measurements in overall population. Subgroup analysis showed a statistically significant difference (p = 0.04) for left ventricular ejection fraction (LVEF) in patients with a dilated phenotype; showing a minimum overestimation tendency for 3D cine kat ARC (2D cine bSSFP LVEF = 46.44 ± 15.83% vs 3D cine kat-ARC LVEF = 48.36 ± 16.50 %).

CONCLUSIONS

3D cine kat-ARC 3D sequences allow an accurate evaluation of biventricular volumes and function in a single breath hold.

Sex differences in left ventricular remodelling, myocardial fibrosis and mortality after aortic valve replacement

OBJECTIVES

To investigate sex differences in left ventricular remodelling and outcome in patients undergoing surgical or transcatheter aortic valve replacement (SAVR/TAVR).

METHODS

In this multicentre, observational, outcome study with imaging core-lab analysis, patients with severe aortic stenosis (AS) listed for intervention at one of six UK centres were prospectively recruited and underwent cardiovascular magnetic resonance imaging. The primary endpoint was all-cause mortality and secondary endpoint was cardiovascular mortality.

RESULTS

674 patients (425 men, 249 women, age 75±14 years) were included: 399 SAVR, 275 TAVR. Women were older, had higher surgical risk scores and underwent TAVR more frequently (53% vs 33.6%, p<0.001). More men had bicuspid aortic valves (BAVs) (26.7% vs 14.9%, p<0.001) and demonstrated more advanced remodelling than women. During a median follow-up of 3.6 years, 145 (21.5%) patients died, with no significant sex difference in all-cause mortality (23.3% vs 20.5%, p=0.114), but higher cardiovascular mortality in women (13.7% vs 8.5%, p=0.012). There were no significant sex-related differences in outcome in the SAVR or TAVR subgroups, or after excluding those with BAV. Factors independently associated with all-cause mortality were age, left ventricular ejection fraction (LVEF), BAV (better) and myocardial fibrosis detected with late gadolinium enhancement (LGE) in men, and age, LVEF and LGE in women. Age and LGE were independently associated with cardiovascular mortality in both sexes.

CONCLUSIONS

Men demonstrate more advanced remodelling in response to a similar severity of AS. The higher cardiovascular mortality observed in women following AVR is accounted for by women having less BAV and higher risk scores resulting in more TAVR. LGE is associated with a worse prognosis in both sexes.

480Right ventricular dysfunction is associated with late mortality in severe aortic stenosis: results from a multi-centre outcome study in patients undergoing aortic valve replacement

Background

The right ventricle (RV) is relatively understudied and often not routinely assessed in aortic stenosis (AS). However, there are several potential reasons for its importance. RV function is sensitive to left-sided afterload changes which can result in pulmonary hypertension (PH) in severe AS. PH is also a recognised predictor of poor prognosis in AS, but RV afterload and function can be difficult to assess. Cardiovascular magnetic resonance (CMR) may reveal unrecognised RV dysfunction and simultaneously evaluate other prognostic markers in AS.

Purpose

To investigate preoperative RV function assessed by CMR in severe AS and its association with mortality after aortic valve replacement (AVR).

Methods

674 severe AS patients listed for either surgical or percutaneous AVR at six cardiothoracic centres underwent preoperative CMR (for ventricular function, mass and scar) along with echocardiography for valve severity. Scans were core-lab analysed for LV and RV volumes, function and scar quantification. Eight patients were excluded due to inadequate RV image quality for a total of 666 patients finally included. All-cause mortality was tracked for a minimum of 2 years after AVR.

Results

107 (16%) of severe AS undergoing invasive AVR had a RV ejection fraction (RVEF) <55%. CMR detected overt RV dysfunction (RVEF <50%) in 61 (9%) patients. During a median 3.6 years follow-up, 145 (22%) patients died. Baseline RV dysfunction was the most powerful predictor of all-cause mortality (hazard ratio [HR] 2.5, 95% CI 1.6–3.9, p<0.0001). RV function was independent from other clinical characteristics but associated with signs of LV maladaptation (LV ejection fraction [LVEF] and late gadolinium enhancement [LGE]). The strongest Cox multivariable model for all-cause mortality accounted for RV dysfunction, age and LGE (adjusted HRs 1.7, 1.1, 2.2, respectively). Even early stages of pre-procedural RV dysfunction (RVEF 45–50%) were associated with reduced long-term survival.

Cox and Kaplan-Meier for all-cause death

Conclusion

One out of 6 patients with severe AS undergoing valve replacement manifests a reduction in RV function detectable by CMR. Those with RV dysfunction (RVEF<50%) have a 2.5-fold increase in all-cause mortality after AVR at 3.6 years. Whilst RV dysfunction is associated with LV maladaptation (LGE, LVEF), it is a powerful independent factor associated with all-cause mortality and impacts survival even at early stages. Thus, the RV appears to be important in cardiac adaptation to AS and longevity after AS intervention.

Acknowledgement/Funding

British Heart Foundation and National Institute of Health Research

P5273Trabecular complexity as a subclinical structural alteration in Fabry cardiomyopathy: a cardiac magnetic resonance study

Background

Heart involvement represents the main cause of death in Fabry Disease (FD), thus its early detection is important to define the optimal therapeutic strategy. Recently, a disproportionate increase in myocardial trabeculation has been described in FD by cardiac magnetic resonance (CMR), even in early (prehypertrophic) stage of the disease. In addition, CMR with T1 mapping can identity the presence of myocardial sphingolipid storage (causing lowering of native T1 values) in more than 50% of FD patients with no LVH. However, it is not clear whether a relationship exists between trabecular complexity and sphingolipid storage in FD.

Aim

To explore the association between myocardial trabecular complexity, quantified by endocardial border fractal analysis, and sphingolipid storage, described by CMR T1 mapping, in different stages of Fabry cardiomyopathy.

Methods

Study population included 60 subjects: 15 FD patients with no detectable signs of cardiac involvement (no LVH, normal T1; 2 M, age 30.6±14; Group 1); 15 FD patients with early sphingolipid storage (no LVH, low T1; 9 M, age 33±9.6; Group 2); 15 FD patients with LVH (11 M, age 53.5±9.6; Group 3); 15 healthy controls (9 M, age 34±10). Patients and controls underwent CMR with T1 mapping; disease severity was quantified using Mainz Severity Score Index (MSSI). Myocardial trabecular fractal dimension was evaluated, blinded to patients'characteristics, on short axis cine images using the Image J dedicated plug-in FracLac, deriving the following parameters: total, basal, mid-ventricular and apical fractal dimensions.

Results

Total fractal dimension was higher in all Fabry groups compared to controls. Indeed, a gradient of total fractal dimension was observed, with this parameter gradually increasing from healthy controls to Groups 3 (1.27±0.02 in controls vs 1.29±0.02 in Group 1 vs 1.30±0.02 in Group 2 vs 1.34±0.02 in Group 3; p<0.001) (Figure 1A). Interestingly, both total and basal fractal dimensions were significantly higher in Group 1 compared to controls (1.27±0.02 vs 1.29±0.02, p=0.044 and 1.26±0.04 vs 1.30±0.03; p=0.007, respectively). Moreover, considering the total population, fractal dimension showed significant correlations with: i) T1 values (r=−0.567; p<0.001 - Figure 1B); ii) LV mass (r=0.674, p<0.001); iii) trabecular mass expressed as percentage of global LV mass (r=0.611; p<0.001); iv) MSSI (r=0.535; p<0.001).

Conclusion

Cardiac involvement in FD is characterized by a progressive increase in fractal dimension of endocardial trabeculae (Figure 1C). Both total and basal myocardial trabeculation are increased in Fabry patients even before the presence of detectable sphingolipid storage, thus representing a very early sign of cardiac involvement.

Myocardial Scar and Mortality in Severe Aortic Stenosis

Supplemental Digital Content is available in the text.

Background:

Aortic valve replacement (AVR) for aortic stenosis is timed primarily on the development of symptoms, but late surgery can result in irreversible myocardial dysfunction and additional risk. The aim of this study was to determine whether the presence of focal myocardial scar preoperatively was associated with long-term mortality.

Methods:

In a longitudinal observational outcome study, survival analysis was performed in patients with severe aortic stenosis listed for valve intervention at 6 UK cardiothoracic centers. Patients underwent preprocedural echocardiography (for valve severity assessment) and cardiovascular magnetic resonance for ventricular volumes, function and scar quantification between January 2003 and May 2015. Myocardial scar was categorized into 3 patterns (none, infarct, or noninfarct patterns) and quantified with the full width at half-maximum method as percentage of the left ventricle. All-cause mortality and cardiovascular mortality were tracked for a minimum of 2 years.

Results:

Six hundred seventy-four patients with severe aortic stenosis (age, 75±14 years; 63% male; aortic valve area, 0.38±0.14 cm²/m²; mean gradient, 46±18 mm Hg; left ventricular ejection fraction, 61.0±16.7%) were included. Scar was present in 51% (18% infarct pattern, 33% noninfarct). Management was surgical AVR (n=399) or transcatheter AVR (n=275). During follow-up (median, 3.6 years), 145 patients (21.5%) died (52 after surgical AVR, 93 after transcatheter AVR). In multivariable analysis, the factors independently associated with all-cause mortality were age (hazard ratio [HR], 1.50; 95% CI, 1.11–2.04; P=0.009, scaled by epochs of 10 years), Society of Thoracic Surgeons score (HR, 1.12; 95% CI, 1.03–1.22; P=0.007), and scar presence (HR, 2.39; 95% CI, 1.40–4.05; P=0.001). Scar independently predicted all-cause (26.4% versus 12.9%; P<0.001) and cardiovascular (15.0% versus 4.8%; P<0.001) mortality, regardless of intervention (transcatheter AVR, P=0.002; surgical AVR, P=0.026 [all-cause mortality]). Every 1% increase in left ventricular myocardial scar burden was associated with 11% higher all-cause mortality hazard (HR, 1.11; 95% CI, 1.05–1.17; P<0.001) and 8% higher cardiovascular mortality hazard (HR, 1.08; 95% CI, 1.01–1.17; P<0.001).

Conclusions:

In patients with severe aortic stenosis, late gadolinium enhancement on cardiovascular magnetic resonance was independently associated with mortality; its presence was associated with a 2-fold higher late mortality.