Cardiac magnetic resonance identifies raised left ventricular filling pressure: prognostic implications

CMR provides comparable measurements of diastolic function as echocardiography

Clinical application of cardiac magnetic resonance (CMR) is expanding but CMR assessment of LV diastolic function is still being validated. The purpose of this study was to validate assessments of left ventricular (LV) diastolic dysfunction (DD) using CMR by comparing with transthoracic echocardiography (TTE) performed on the same day. Patients with suspected or diagnosed cardiomyopathy (n = 63) and healthy volunteers (n = 24) were prospectively recruited and included in the study. CMR diastolic parameters were measured on cine images and velocity-encoded phase contrast cine images and compared with corresponding parameters measured on TTE. A contextual correlation feature tracking method was developed to calculate the mitral annular velocity curve. LV DD was classified by CMR and TTE following 2016 guidelines. Overall DD classification was 78.1% concordant between CMR and TTE (p < 0.0001). The trans-mitral inflow parameters correlated well between the two modalities (E, r = 0.78; A, r = 0.90; E/A, r = 0.82; all p < 0.0001) while the remaining diastolic parameters showed moderate correlation (e', r = 0.64; E/e', r = 0.54; left atrial volume index (LAVi), r = 0.61; all p < 0.0001). Classification of LV diastolic function by CMR showed good concordance with standardized grades established for TTE. CMR-based LV diastolic function may be integrated in routine clinical practice.Name of the registry: Technical Development of Cardiovascular Magnetic Resonance Imaging. Trial registration number: NCT00027170. Date of registration: November 26, 2001. URL of trial registry record: https://clinicaltrials.gov/ct2/show/NCT00027170.

Impact of tafamidis on myocardial function and CMR tissue characteristics in transthyretin amyloid cardiomyopathy

AIMS

Tafamidis improves clinical outcomes in transthyretin amyloid cardiomyopathy (ATTR-CM), yet how tafamidis affects cardiac structure and function remains poorly described. This study prospectively analysed the effect of tafamidis on 12-month longitudinal changes in cardiac structure and function by cardiac magnetic resonance (CMR) compared with the natural course of disease in an untreated historic control cohort.

METHODS AND RESULTS

ATTR-CM patients underwent CMR at tafamidis initiation and at 12 months. Untreated patients with serial CMRs served as reference to compare biventricular function, global longitudinal strain (GLS), LV mass and extracellular volume fraction (ECV). Thirty-six tafamidis-treated (n = 35; 97.1% male) and 15 untreated patients (n = 14; 93.3% male) with a mean age of 78.3 ± 6.5 and 76.9 ± 6.5, respectively, and comparable baseline characteristics were included. Tafamidis was associated with preserving biventricular function (LVEF (%): 50.5 ± 12 to 50.7 ± 11.5, P = 0.87; RVEF (%): 48.2 ± 10.4 to 48.2 ± 9.4, P = 0.99) and LV-GLS (-9.6 ± 3.2 to -9.9 ± 2.4%; P = 0.595) at 12 months, while a significantly reduced RV-function (50.8 ± 7.3 to 44.2 ± 11.6%, P = 0.028; P (change over time between groups) = 0.032) and numerically worsening LVGLS (-10.9 ± 3.3 to -9.1 ± 2.9%, P = 0.097; P (change over time between groups) = 0.048) was observed without treatment. LV mass significantly declined with tafamidis (184.7 ± 47.7 to 176.5 ± 44.3 g; P = 0.011), yet remained unchanged in untreated patients (163.8 ± 47.5 to 171.2 ± 39.7 g P = 0.356, P (change over time between groups) = 0.027). Irrespective of tafamidis, ECV and native T1-mapping did not change significantly from baseline to 12-month follow-up (P > 0.05).

CONCLUSIONS

Compared with untreated ATTR-CM patients, initiation of tafamidis preserved CMR-measured biventricular function and reduced LV mass at 12 months. ECV and native T1-mapping did not change significantly comparable to baseline in both groups.

Noninvasive Prediction of Pulmonary Capillary Wedge Pressure in Patients With Normal Left Ventricular Ejection Fraction: Comparison of Cardiac Magnetic Resonance With Comprehensive Echocardiography

BACKGROUND

Cardiac magnetic resonance (CMR) was recently reported to predict mean pulmonary capillary wedge pressure (PCWP). However, there is a paucity of data on its accuracy for estimation of PCWP in patients with normal left ventricular (LV) ejection fraction (EF). We sought to examine its accuracy against the invasive gold standard and to compare it with the accuracy of comprehensive echocardiography.

METHODS

Stable patients with EF of ≥50% who underwent right heart catheterization, CMR, and echocardiographic imaging within 1 week were included. Pulmonary capillary wedge pressure was estimated by CMR using a previously validated equation where PCWP is estimated based on the left atrial maximum volume and LV mass. Echocardiographic estimation of PCWP was based on 2016 American Society of Echocardiography/European Association of Cardiovascular Imaging guidelines, taking into account the presence of myocardial disease.

RESULTS

The mean age of the 79 patients was 55 ± 15 years, and 58.2% were female. There were 33 patients with PCWP >15 mm Hg by right heart catheterization. Cardiac magnetic resonance prediction of PCWP had an area under the curve (AUC) = 0.72. In comparison, echocardiographic prediction of PCWP showed a higher accuracy (AUC = 0.87 vs AUC = 0.72; P = .008).

CONCLUSIONS

In patients with normal LV EF, CMR estimation of mean PCWP based on LV mass and left atrial volume has modest accuracy for detecting patients with mean PCWP >15 mm Hg. Comprehensive echocardiography predicts elevated PCWP with higher accuracy in comparison with CMR.

Sex-specific cardiac magnetic resonance pulmonary capillary wedge pressure

Aims

Heart failure (HF) with preserved ejection fraction disproportionately affects women. There are no validated sex-specific tools for HF diagnosis despite widely reported differences in cardiac structure. This study investigates whether sex, as assigned at birth, influences cardiac magnetic resonance (CMR) assessment of left ventricular filling pressure (LVFP), a hallmark of HF agnostic to ejection fraction.

Methods and results

A derivation cohort of patients with suspected pulmonary hypertension and HF from the Sheffield centre underwent invasive right heart catheterization and CMR within 24 h of each other. A sex-specific CMR model to estimate LVFP, measured as pulmonary capillary wedge pressure (PCWP), was developed using multivariable regression. A validation cohort of patients with confirmed HF from the Leeds centre was used to evaluate for the primary endpoints of HF hospitalization and major adverse cardiovascular events (MACEs). Comparison between generic and sex-specific CMR-derived PCWP was undertaken. A total of 835 (60% female) and 454 (36% female) patients were recruited into the derivation and validation cohorts respectively. A sex-specific model incorporating left atrial volume and left ventricular mass was created. The generic CMR PCWP showed significant differences between males and females (14.7 ± 4 vs. 13 ± 3.0 mmHg, P > 0.001), not present with the sex-specific CMR PCWP (14.1 ± 3 vs. 13.8 mmHg, P = 0.3). The sex-specific, but not the generic, CMR PCWP was associated with HF hospitalization (hazard ratio 3.9, P = 0.0002) and MACE (hazard ratio 2.5, P = 0.001) over a mean follow-up period of 2.4 ± 1.2 years.

Conclusion

Accounting for sex improves precision and prognostic performance of CMR biomarkers for HF.

Use of Real-Time Cine MRI to Assess the Respirophasic Variation of the Inferior Vena Cava-Proof-of-Concept and Validation Against Transthoracic Echocardiography

BACKGROUND

In clinical practice, the right heart filling status is assessed using the respirophasic variation of the inferior vena cava (IVC) assessed by transthoracic echocardiography (TTE) showing moderate correlations with the catheter-based reference standard.

PURPOSE

To develop and validate a similar approach using MRI.

STUDY TYPE

Prospective.

POPULATION

37 male elite cyclists (mean age 26 ± 4 years).

FIELD STRENGTH/SEQUENCE

Real-time balanced steady-state free-precession cine sequence at 1.5 Tesla.

ASSESSMENT

Respirophasic variation included assessment of expiratory size of the upper hepatic part of the IVC and degree of inspiratory collapse expressed as collapsibility index (CI). The IVC was studied either in long-axis direction (TTE) or using two transverse slices, separated by 30 mm (MRI) during operator-guided deep breathing. For MRI, in addition to the TTE-like diameter, IVC area and major and minor axis diameters were also assessed, together with the corresponding CIs.

STATISTICAL TESTS

Repeated measures ANOVA test with Bonferroni correction. Intraclass correlation coefficient (ICC) and Bland-Altman analysis for intrareader and inter-reader agreement. A P value <0.05 was considered statistically significant.

RESULTS

No significant differences in expiratory IVC diameter were found between TTE and MRI, i.e., 25 ± 4 mm vs. 25 ± 3 mm (P = 0.242), but MRI showed a higher CI, i.e., 76% ± 14% vs. 66% ± 14% (P < 0.05). As the IVC presented a noncircular shape, i.e., major and minor expiratory diameter of 28 ± 4 mm and 21 ± 4 mm, respectively, the CI varied according to the orientation, i.e., 63% ± 27% vs. 75% ± 16%, respectively. Alternatively, expiratory IVC area was 4.3 ± 1.1 cm2 and showed a significantly higher CI, i.e., 86% ± 14% than diameter-based CI (P < 0.05). All participants showed a CI >50% with MRI versus 35/37 (94%) with TTE. ICC values ranged 0.546-0.841 for MRI and 0.545-0.704 for TTE.

CONCLUSION

Assessment of the respirophasic IVC variation is feasible with MRI. Adding this biomarker may be of particular use in evaluating heart failure patients.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 2.

Cardiovascular multimodality imaging in women: a scientific statement of the European Association of Cardiovascular Imaging of the European Society of Cardiology

Cardiovascular diseases (CVD) represent an important cause of mortality and morbidity in women. It is now recognized that there are sex differences regarding the prevalence and the clinical significance of the traditional cardiovascular (CV) risk factors as well as the pathology underlying a range of CVDs. Unfortunately, women have been under-represented in most CVD imaging studies and trials regarding diagnosis, prognosis, and therapeutics. There is therefore a clear need for further investigation of how CVD affects women along their life span. Multimodality CV imaging plays a key role in the diagnosis of CVD in women as well as in prognosis, decision-making, and monitoring of therapeutics and interventions. However, multimodality imaging in women requires specific consideration given the differences in CVD between the sexes. These differences relate to physiological changes that only women experience (e.g. pregnancy and menopause) as well as variation in the underlying pathophysiology of CVD and also differences in the prevalence of certain conditions such as connective tissue disorders, Takotsubo, and spontaneous coronary artery dissection, which are all more common in women. This scientific statement on CV multimodality in women, an initiative of the European Association of Cardiovascular Imaging of the European Society of Cardiology, reviews the role of multimodality CV imaging in the diagnosis, management, and risk stratification of CVD, as well as highlights important gaps in our knowledge that require further investigation.

Validation of Left Atrial Volume Correction for Single Plane Method on Four-Chamber Cine Cardiac MRI

BACKGROUND

Left atrial (LA) assessment is an important marker of adverse cardiovascular outcomes. Cardiovascular magnetic resonance (CMR) accurately quantifies LA volume and function based on biplane long-axis imaging. We aimed to validate single-plane-derived LA indices against the biplane method to simplify the post-processing of cine CMR.

METHODS

In this study, 100 patients from Leeds Teaching Hospitals were used as the derivation cohort. Bias correction for the single plane method was applied and subsequently validated in 79 subjects.

RESULTS

There were significant differences between the biplane and single plane mean LA maximum and minimum volumes and LA ejection fraction (EF) (all p < 0.01). After correcting for biases in the validation cohort, significant correlations in all LA indices were observed (0.89 to 0.98). The area under the curve (AUC) for the single plane to predict biplane cutoffs of LA maximum volume ≥ 112 mL was 0.97, LA minimum volume ≥ 44 mL was 0.99, LA stroke volume (SV) ≤ 21 mL was 1, and LA EF ≤ 46% was 1, (all p < 0.001).

CONCLUSIONS

LA volumetric and functional assessment by the single plane method has a systematic bias compared to the biplane method. After bias correction, single plane LA volume and function are comparable to the biplane method.

Aortic flow is abnormal in HFpEF

Aims

Turbulent aortic flow makes the cardiovascular system less effective. It remains unknown if patients with heart failure with preserved ejection fraction (HFpEF) have disturbed aortic flow. This study sought to investigate advanced markers of aortic flow disturbances in HFpEF.

Methods

This case-controlled observational study used four-dimensional flow cardiovascular magnetic resonance derived, two-dimensional phase-contrast reformatted plane data at an orthogonal plane just above the sino-tubular junction. We recruited 10 young healthy controls (HCs), 10 old HCs and 23 patients with HFpEF. We analysed average systolic aortic flow displacement (FDsavg), systolic flow reversal ratio (sFRR) and pulse wave velocity (PWV). In a sub-group analysis, we compared old HCs versus age-gender-matched HFpEF (N=10).

Results

Differences were significant in mean age (P<0.001) among young HCs (22.9±3.5 years), old HCs (60.5±10.2 years) and HFpEF patients (73.7±9.7 years). FDsavg, sFRR and PWV varied significantly (P<0.001) in young HCs (8±4%, 2±2%, 4±2m/s), old HCs (16±5%, 7±6%, 11±8m/s), and HFpEF patients (23±10%, 11±10%, 8±3). No significant PWV differences existed between old HCs and HFpEF.HFpEF had significantly higher FDsavg versus old HCs (23±10% vs 16±5%, P<0.001). A FDsavg > 17.7% achieved 74% sensitivity, 70% specificity for differentiating them. sFRR was notably higher in HFpEF (11±10% vs 7±6%, P<0.001). A sFRR > 7.3% yielded 78% sensitivity, 70% specificity in differentiating these groups. In sub-group analysis, FDsavg remained distinctly elevated in HFpEF (22.4±9.7% vs 16±4.9%, P=0.029). FDsavg of >16% showed 100% sensitivity and 70% specificity (P=0.01). Similarly, sFRR remained significantly higher in HFpEF (11.3±9.5% vs 6.6±6.4%, P=0.007). A sFRR of >7.2% showed 100% sensitivity and 60% specificity (P<0.001).

Conclusion

Aortic flow haemodynamics namely FDsavg and sFRR are significantly affected in ageing and HFpEF patients.

Rest and exercise-stress estimated pulmonary capillary wedge pressure using real-time free-breathing cardiovascular magnetic resonance imaging

BACKGROUND

Identification of increased pulmonary capillary wedge pressure (PCWP) by right heart catheterization (RHC) is the reference standard for the diagnosis of heart failure with preserved ejection fraction (HFpEF). Recently, cardiovascular magnetic resonance (CMR) imaging estimation of PCWP at rest was introduced as a non-invasive alternative. Since many patients are only identified during physiological exercise-stress, we hypothesized that novel exercise-stress CMR-derived PCWP emerges superior compared to its assessment at rest.

METHODS

The HFpEF-Stress Trial prospectively recruited 75 patients with exertional dyspnea and diastolic dysfunction who then underwent rest and exercise-stress RHC and CMR. HFpEF was defined according to PCWP (overt HFpEF ≥15 mmHg at rest, masked HFpEF ≥25 mmHg during exercise-stress). CMR-derived PCWP was calculated based on previously published formula using left ventricular mass and either biplane left atrial volume (LAV) or monoplane left atrial area (LAA).

RESULTS

LAV (rest/stress: r = 0.50/r = 0.55, p < 0.001) and LAA PCWP (rest/stress: r = 0.50/r = 0.48, p < 0.001) correlated significantly with RHC-derived PCWP while numerically overestimating PCWP at rest and underestimating PCWP during exercise-stress. LAV and LAA PCWP showed good diagnostic accuracy to detect HFpEF (area under the receiver operating characteristic curve (AUC) LAV rest 0.73, stress 0.81; LAA rest 0.72, stress 0.77) with incremental diagnostic value for the detection of masked HFpEF using exercise-stress (AUC LAV rest 0.54 vs stress 0.67, p = 0.019, LAA rest 0.52 vs stress 0.66, p = 0.012). LAV but not LAA PCWP during exercise-stress was a predictor for 24 months hospitalization independent of a medical history for atrial fibrillation (hazard ratio (HR) 1.26, 95% confidence interval 1.02-1.55, p = 0.032).

CONCLUSION

Non-invasive PCWP correlates well with the invasive reference at rest and during exercise stress. There is overall good diagnostic accuracy for HFpEF assessment using CMR-derived estimated PCWP despite deviations in absolute agreement. Non-invasive exercise derived PCWP may particularly facilitate detection of masked HFpEF in the future.

Left ventricular to left arial volume ratio in the assessment of filling pressure in patients with dyspnoea and preserved ejection fraction

Introduction

Assessing filling pressure (FP) remains a clinical challenge despite advancements in non-invasive imaging techniques. This study investigates the utility of echocardiographic left ventricular (LV) to left atrial (LA) volume ratio in estimating the resting FP in patients with dyspnoea and preserved ejection fraction (EF).

Methods

This study is a prospective, single-centre analysis of 53 consecutive patients with dyspnoea (New York Heart Association grade 2 or 3) and LVEF of ≥50% (mean age 71 ± 10 years) who underwent cardiac catheterisation, including direct measurement of LA pressure at rest using retrograde technique. Echocardiographic data were obtained 1.5 ± 1.0 h after cardiac catheterisation. The patients were divided into two groups: Group 1 consisted of individuals with elevated FP, indicated by a mean LA pressure or mean pulmonary capillary wedge pressure of >12 mmHg, and Group 2 comprised of patients with normal FP. The LV and LA volumes were measured at three specific points: the minimum volume (LVES, LAmin), the volume during diastasis (LVdias, LAdias), and the maximum volume (LVED, LAmax). The corresponding LV/LA volume ratios were analysed: end-systole (LVES/LAmax), diastasis (LVdias/LAdias), and end-diastole (LVED/LAmin).

Results

The patients in Group 1 exhibited lower LV/LA volume ratios compared with those in Group 2 (LVES/LAmax 0.44 ± 0.12 vs. 0.60 ± 0.23, P = 0.0032; LVdias/LAdias 1.13 ± 0.30 vs. 1.56 ± 0.49, P = 0.0007; LVED/LAmin 2.71 ± 1.57 vs. 4.44 ± 1.70, P = 0.0004). The LV/LA volume ratios correlated inversely with an increased FP (LVES/LAmax, r = -0.40, P = 0.0033; LVdias/LAdias, r = -0.45, P = 0.0007; LVED/LAmin, r = -0.55, P < 0.0001). Among all the measurements, the LVdias/LAdias ratio demonstrated the highest discriminatory power to distinguish patients with elevated FP from normal FP, with a cut-off value of ≤1.24 [area under the curve (AUC) = 0.822] for the entire group, encompassing both sinus rhythm and atrial fibrillation. For patients in sinus rhythm specifically, the cut-off value was ≤1.28 (AUC = 0.799), with P < 0.0001 for both. The LVdias/LAdias index demonstrated non-inferiority to the E/e' ratio [ΔAUC = 0.159, confidence interval (CI) = -0.020-0.338; P = 0.0809], while surpassing the indices of LA reservoir function (ΔAUC = 0.249, CI = 0.044-0.454; P = 0.0176), LA reservoir strain (ΔAUC = 0.333, CI = 0.149-0.517; P = 0.0004), and LAmax index (ΔAUC = 0.224, CI = 0.043-0.406; P = 0.0152) in diagnosing patients with elevated FP.

Conclusion

The study presents a straightforward and reproducible method for non-invasive estimation of FP using routine TTE in patients with dyspnoea and preserved EF. The LVdias/LAdias index emerges as a promising indicator for identifying elevated FP, demonstrating comparable or even superior performance to established parameters.

Comprehensive diagnostic workup in patients with suspected heart failure and preserved ejection fraction

Diagnosis of heart failure with preserved ejection fraction (HFpEF) can be challenging and it could require different tests, some of which are affected by limited availability. Nowadays, considering that new therapies are available for HFpEF and related conditions, a prompt and correct diagnosis is relevant. However, the diagnostic role of biomarker level, imaging tools, score-based algorithms and invasive evaluation, should be based on the strengths and weaknesses of each test. The aim of this review is to help the clinician in diagnosing HFpEF, overcoming the diagnostic uncertainty and disentangling among the different underlying causes, in order to properly treat this kind of patient.

Cardiac MR modelling of systolic and diastolic blood pressure

AIMS

Blood pressure (BP) is a crucial factor in cardiovascular health and can affect cardiac imaging assessments. However, standard outpatient cardiovascular MR (CMR) imaging procedures do not typically include BP measurements prior to image acquisition. This study proposes that brachial systolic BP (SBP) and diastolic BP (DBP) can be modelled using patient characteristics and CMR data.

METHODS

In this multicentre study, 57 patients from the PREFER-CMR registry and 163 patients from other registries were used as the derivation cohort. All subjects had their brachial SBP and DBP measured using a sphygmomanometer. Multivariate linear regression analysis was applied to predict brachial BP. The model was subsequently validated in a cohort of 169 healthy individuals.

RESULTS

Age and left ventricular ejection fraction were associated with SBP. Aortic forward flow, body surface area and left ventricular mass index were associated with DBP. When applied to the validation cohort, the correlation coefficient between CMR-derived SBP and brachial SBP was (r=0.16, 95% CI 0.011 to 0.305, p=0.03), and CMR-derived DBP and brachial DBP was (r=0.27, 95% CI 0.122 to 0.403, p=0.0004). The area under the curve (AUC) for CMR-derived SBP to predict SBP>120 mmHg was 0.59, p=0.038. Moreover, CMR-derived DBP to predict DBP>80 mmHg had an AUC of 0.64, p=0.002.

CONCLUSION

CMR-derived SBP and DBP models can estimate brachial SBP and DBP. Such models may allow efficient prospective collection, as well as retrospective estimation of BP, which should be incorporated into assessments due to its critical effect on load-dependent parameters.

Left atrial expansion index measured with cardiovascular magnetic resonance estimates pulmonary capillary wedge pressure in dilated cardiomyopathy

BACKGROUND

Pulmonary capillary wedge pressure (PCWP) assessment is fundamental for managing dilated cardiomyopathy (DCM) patients. Although cardiovascular magnetic resonance (CMR) has become the gold-standard imaging technique for evaluating cardiac chamber volume and function, PCWP is not routinely assessed with CMR. Therefore, this study aimed to validate the left atrial expansion index (LAEI), a LA reservoir function parameter able to estimate filling pressure with echocardiography, as a novel CMR-measured parameter for non-invasive PCWP estimation in DCM patients.

METHODS

We performed a retrospective, single-center, cross-sectional study. We included electively admitted DCM patients referred to our tertiary center for further diagnostic evaluation that underwent a clinically indicated right heart catheterization (RHC) and CMR within 24 h. PCWP invasively measured during RHC was used as the reference. LAEI was calculated from CMR-measured LA maximal and minimal volumes as LAEI =  ( (LAVmax-LAVmin)/LAVmin) × 100.

RESULTS

We enrolled 126 patients (47 ± 14 years; 68% male; PCWP = 17 ± 9.3 mmHg) randomly divided into derivation (n = 92) and validation (n = 34) cohorts with comparable characteristics. In the derivation cohort, the log-transformed (ln) LAEI showed a strong linear correlation with PCWP (r = 0.81, p < 0.001) and remained a strong independent PCWP determinant over clinical and conventional CMR parameters. Moreover, lnLAEI accurately identified PCWP ≥ 15 mmHg (AUC = 0.939, p < 0.001), and the optimal cut-off identified (lnLAEI ≤ 3.85) in the derivation cohort discriminated PCWP ≥ 15 mmHg with 82.4% sensitivity, 88.2% specificity, and 85.3% accuracy in the validation cohort. Finally, the equation PCWP = 52.33- (9.17xlnLAEI) obtained from the derivation cohort predicted PCWP (-0.1 ± 5.7 mmHg) in the validation cohort.

CONCLUSIONS

In this cohort of DCM patients, CMR-measured LAEI resulted in a novel and useful parameter for non-invasive PCWP evaluation.

Supra-Normal Left Ventricular Function

Heart failure (HF) is often categorized by left ventricular (LV) ejection fraction (LVEF). A new category of HF characterized by supra-normal LVEF (>65%), named HF with supra-normal ejection fraction (HFsnEF), has been recently proposed. Some studies reported that patients with supra-normal LVEF might have an increased risk of long-term major adverse cardiovascular events and U-shaped mortality patterns. Currently, the prognosis of HFsnEF is not well established but seems to be associated with an increased risk of long-term major adverse cardiovascular events. It has been reported that HFsnEF is more prevalent in women and is associated with higher prevalence of nonischemic HF, higher blood urea nitrogen plasma levels, lower levels of natriuretic peptides, and to be less likely treated with β blockers. The pathophysiology of HFsnEF would be associated with microvascular dysfunction because of microvascular inflammation or reduced coronary flow reserve, and low stroke volume index with smaller cardiac chamber dimensions and concentric LV geometry. In this study, we systematically reviewed published data on patients with s supra-normal LV function and reported its definition, proposed pathophysiology, phenotypes, diagnostic strategy, and prognosis.

The Left Atrial Area Derived Cardiovascular Magnetic Resonance Left Ventricular Filling Pressure Equation Shows Superiority over Integrated Echocardiography

Background and objectives: Evaluating left ventricular filling pressure (LVFP) plays a crucial role in diagnosing and managing heart failure (HF). While traditional assessment methods involve multi-parametric transthoracic echocardiography (TTE) or right heart catheterisation (RHC), cardiovascular magnetic resonance (CMR) has emerged as a valuable diagnostic tool in HF. This study aimed to assess a simple CMR-derived model to estimate pulmonary capillary wedge pressure (PCWP) in a cohort of patients with suspected or proven heart failure and to investigate its performance in risk-stratifying patients. Materials and methods: A total of 835 patients with breathlessness were evaluated using RHC and CMR and split into derivation (85%) and validation cohorts (15%). Uni-variate and multi-variate linear regression analyses were used to derive a model for PCWP estimation using CMR. The model's performance was evaluated by comparing CMR-derived PCWP with PCWP obtained from RHC. Results: A CMR-derived PCWP incorporating left ventricular mass and the left atrial area (LAA) demonstrated good diagnostic accuracy. The model correctly reclassified 66% of participants whose TTE was 'indeterminate' or 'incorrect' in identifying raised filling pressures. On survival analysis, the CMR-derived PCWP model was predictive for mortality (HR 1.15, 95% CI 1.04-1.28, p = 0.005), which was not the case for PCWP obtained using RHC or TTE. Conclusions: The simplified CMR-derived PCWP model provides an accurate and practical tool for estimating PCWP in patients with suspected or proven heart failure. Its predictive value for mortality suggests the ability to play a valuable adjunctive role in echocardiography, especially in cases with unclear echocardiographic assessment.

Cardiac Magnetic Resonance Left Ventricular Filling Pressure Is Associated with NT-proBNP in Patients with New Onset Heart Failure

Background and Objectives: Cardiovascular magnetic resonance (CMR) is emerging as an important imaging tool for sub-phenotyping and estimating left ventricular (LV) filling pressure (LVFP). The N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) is released from cardiac myocytes in response to mechanical load and wall stress. This study sought to investigate if CMR-derived LVFP is associated with the serum levels of NT-proBNP and, in addition, if it provides any incremental prognostic value in heart failure (HF). Materials and Methods: This study recruited 380 patients diagnosed with HF who underwent same-day CMR and clinical assessment between February 2018 and January 2020. CMR-derived LVFP was calculated, as previously, from long- and short-axis cines. During CMR assessment, serum NT-proBNP was measured. The pathological cut-offs were defined as follows: NT-proBNP ≥ 125 pg/mL and CMR LVFP > 15 mmHg. The incidence of HF hospitalisation was treated as a clinical outcome. Results: In total, 305 patients had NT-proBNP ≥ 125 pg/mL. Patients with raised NT-proBNP were older (54 ± 14 vs. 64 ± 11 years, p < 0.0001). Patients with raised NT-proBNP had higher LV volumes and mass. In addition, CMR LVFP was higher in patients with raised NT-proBNP (13.2 ± 2.6 vs. 15.4 ± 3.2 mmHg, p < 0.0001). The serum levels of NT-proBNP were associated with CMR-derived LVFP (R = 0.42, p < 0.0001). In logistic regression analysis, this association between NT-proBNP and CMR LVFP was independent of all other CMR variables, including LV ejection fraction, LV mass, and left atrial volume (coefficient = 2.02, p = 0.002). CMR LVFP demonstrated an independent association with the incidence of HF hospitalisation above NT-proBNP (hazard ratio 2.7, 95% confidence interval 1.2 to 6, p = 0.01). Conclusions: A CMR-modelled LVFP is independently associated with serum NT-proBNP levels. Importantly, it provides an incremental prognostic value over and above serum NT-proBNP levels.

Cardiac magnetic resonance left ventricular filling pressure is linked to symptoms, signs and prognosis in heart failure

AIMS

Left ventricular filling pressure (LVFP) can be estimated from cardiovascular magnetic resonance (CMR). We aimed to investigate whether CMR-derived LVFP is associated with signs, symptoms, and prognosis in patients with recently diagnosed heart failure (HF).

METHODS AND RESULTS

This study recruited 454 patients diagnosed with HF who underwent same-day CMR and clinical assessment between February 2018 and January 2020. CMR-derived LVFP was calculated, as previously, from long- and short-axis cines. CMR-derived LVFP association with symptoms and signs of HF was investigated. Patients were followed for median 2.9 years (interquartile range 1.5-3.6 years) for major adverse cardiovascular events (MACE), defined as the composite of cardiovascular death, HF hospitalization, non-fatal stroke, and non-fatal myocardial infarction. The mean age was 62 ± 13 years, 36% were female (n = 163), and 30% (n = 135) had raised LVFP. Forty-seven per cent of patients had an ejection fraction < 40% during CMR assessment. Patients with raised LVFP were more likely to have pleural effusions [hazard ratio (HR) 3.2, P = 0.003], orthopnoea (HR 2.0, P = 0.008), lower limb oedema (HR 1.7, P = 0.04), and breathlessness (HR 1.7, P = 0.01). Raised CMR-derived LVFP was associated with a four-fold risk of HF hospitalization (HR 4.0, P < 0.0001) and a three-fold risk of MACE (HR 3.1, P < 0.0001). In the multivariable model, raised CMR-derived LVFP was independently associated with HF hospitalization (adjusted HR 3.8, P = 0.0001) and MACE (adjusted HR 3.0, P = 0.0001).

CONCLUSIONS

Raised CMR-derived LVFP is strongly associated with symptoms and signs of HF. In addition, raised CMR-derived LVFP is independently associated with subsequent HF hospitalization and MACE.

Diastology with Cardiac MRI: A Practical Guide

Diastolic filling of the ventricle is a complex interplay of volume and pressure, contingent on active energy-dependent myocardial relaxation and myocardial stiffness. Abnormal diastolic function is the hallmark of the clinical entity of heart failure with preserved ejection fraction (HFpEF), which is now the dominant type of heart failure and is associated with significant morbidity and mortality. Although echocardiography is the current first-line imaging modality used in evaluation of diastolic function, cardiac MRI (CMR) is emerging as an important technique. The principal role of CMR is to categorize the cause of diastolic dysfunction (DD) and distinguish other entities that manifest similarly to HFpEF, particularly infiltrative and pericardial disorders. CMR also provides prognostic information and risk stratification based on late gadolinium enhancement and parametric mapping techniques. Advances in hardware, sequences, and postprocessing software now enable CMR to diagnose and grade DD accurately, a role traditionally assigned to echocardiography. Two-dimensional or four-dimensional velocity-encoded phase-contrast sequences can measure flow and velocities at the mitral inflow, mitral annulus, and pulmonary veins to provide diastolic functional metrics analogous to those at echocardiography. The commonly used cine steady-state free-precession sequence can provide clues to DD including left ventricular mass, left ventricular filling curves, and left atrial size and function. MR strain imaging provides information on myocardial mechanics that further aids in diagnosis and prognosis of diastolic function. Research sequences such as MR elastography and MR spectroscopy can help evaluate myocardial stiffness and metabolism, respectively, providing additional insights on diastolic function. The authors review the physiology of diastolic function, mechanics of diastolic heart failure, and CMR techniques in the evaluation of diastolic function. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Cardiac Imaging Biomarkers in Chronic Kidney Disease

Uremic cardiomyopathy (UC), the peculiar cardiac remodeling secondary to the systemic effects of renal dysfunction, is characterized by left ventricular (LV) diffuse fibrosis with hypertrophy (LVH) and stiffness and the development of heart failure and increased rates of cardiovascular mortality. Several imaging modalities can be used to obtain a non-invasive assessment of UC by different imaging biomarkers, which is the focus of the present review. Echocardiography has been largely employed in recent decades, especially for the determination of LVH by 2-dimensional imaging and diastolic dysfunction by pulsed-wave and tissue Doppler, where it retains a robust prognostic value; more recent techniques include parametric assessment of cardiac deformation by speckle tracking echocardiography and the use of 3D-imaging. Cardiac magnetic resonance (CMR) imaging allows a more accurate assessment of cardiac dimensions, including the right heart, and deformation by feature-tracking imaging; however, the most evident added value of CMR remains tissue characterization. T1 mapping demonstrated diffuse fibrosis in CKD patients, increasing with the worsening of renal disease and evident even in early stages of the disease, with few, but emerging, prognostic data. Some studies using T2 mapping highlighted the presence of subtle, diffuse myocardial edema. Finally, computed tomography, though rarely used to specifically assess UC, might provide incidental findings carrying prognostic relevance, including information on cardiac and vascular calcification. In summary, non-invasive cardiovascular imaging provides a wealth of imaging biomarkers for the characterization and risk-stratification of UC; integrating results from different imaging techniques can aid a better understanding of the physiopathology of UC and improve the clinical management of patients with CKD.

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.

Left atrial acceleration factor as a magnetic resonance 4D flow measure of mean pulmonary artery wedge pressure in pulmonary hypertension

Background

Mean pulmonary artery wedge pressure (PAWP) represents a right heart catheter (RHC) surrogate measure for mean left atrial (LA) pressure and is crucial for the clinical classification of pulmonary hypertension (PH). Hypothesizing that PAWP is related to acceleration of blood throughout the LA, we investigated whether an adequately introduced LA acceleration factor derived from magnetic resonance (MR) four-dimensional (4D) flow imaging could provide an estimate of PAWP in patients with known or suspected PH.

Methods

LA 4D flow data of 62 patients with known or suspected PH who underwent RHC and near-term 1.5 T cardiac MR (ClinicalTrials.gov identifier: NCT00575692) were retrospectively analyzed. Early diastolic LA peak outflow velocity (v_E) as well as systolic (v_S) and early diastolic (v_D) LA peak inflow velocities were determined with prototype software to calculate the LA acceleration factor (α) defined as α = v_E/[(v_S + v_D)/2]. Correlation, regression and Bland-Altman analysis were employed to investigate the relationship between α and PAWP, α-based diagnosis of elevated PAWP (>15 mmHg) was analyzed by receiver operating characteristic curve analysis.

Results

α correlated very strongly with PAWP (r = 0.94). Standard deviation of differences between RHC-derived PAWP and PAWP estimated from linear regression model (α = 0.61 + 0.10·PAWP) was 2.0 mmHg. Employing the linear-regression-derived cut-off α = 2.10, the α-based diagnosis of elevated PAWP revealed the area under the curve 0.97 with sensitivity/specificity 93%/92%.

Conclusions

The very close relationship between the LA acceleration factor α and RHC-derived PAWP suggests α as potential non-invasive parameter for the estimation of PAWP and the distinction between pre- and post-capillary PH.