Cardiac MR Imaging in the Evaluation of Rheumatic Valvular Heart Diseases

Myocardial extracellular volume assessed by cardiovascular magnetic resonance may predict adverse left ventricular remodeling in rheumatic heart disease after valvular surgery

BACKGROUND

Only a few studies to date have focused on the application of cardiovascular magnetic resonance (CMR) in rheumatic heart disease (RHD); in particular, research on the application of T1-mapping CMR sequences is limited. This study aimed to investigate whether diffuse myocardial fibrosis evaluated using preoperative T1 mapping and extracellular volume (ECV) fraction measurement could predict the progression of adverse left ventricular remodeling (LVR) after surgery.

METHODS

A total of 32 adult patients with RHD and 30 healthy controls were recruited. Baseline clinical characteristics, CMR findings, and T1 mapping measurements were compared between the two groups. Transthoracic echocardiography measurements were collected before and after surgery. Patients with an increase in left ventricular end-diastolic volume of >15% or a decrease in left ventricular ejection fraction of >10% were classified into the adverse remodeling group; otherwise, patients were categorized into the non-adverse remodeling group.

RESULTS

Compared with the healthy controls, patients with RHD had impaired biventricular function, enlarged ventricular volume, and increased native T1 and ECV values. Patients in the adverse remodeling group had higher ECV values than those in the non-adverse remodeling group (33.25%±3.67% vs. 28.45%±4.46%, P=0.002). Binary logistic regression analysis showed that the ECV value was associated with adverse LVR (odds ratio: 1.273, P=0.045). ECV was found to be a sensitive biomarker for predicting adverse LVR (area under the curve: 0.78; sensitivity: 75.0%; specificity: 77.3%).

CONCLUSIONS

ECV has potential value for predicting the progression of adverse LVR and for identifying non-responders among patients with RHD undergoing surgery.

Evaluation of aortic stenosis using cardiovascular magnetic resonance: a systematic review & meta-analysis

BACKGROUND

As the average age of patients with severe aortic stenosis (AS) who receive procedural intervention continue to age, the need for non-invasive modalities that provide accurate diagnosis and operative planning is increasingly important. Advances in cardiovascular magnetic resonance (CMR) over the past two decades mean it is able to provide haemodynamic data at the aortic valve, along with high fidelity anatomical imaging.

METHODS

Electronic databases were searched for studies comparing CMR to transthoracic echocardiography (TTE) and transoesophageal echocardiography (TEE) in the diagnosis of AS. Studies were included only if direct comparison was made on matched patients, and if diagnosis was primarily through measurement of aortic valve area (AVA).

RESULTS

Twenty-three relevant, prospective articles were included in the meta-analysis, totalling 1040 individual patients. There was no significant difference in AVA measured as by CMR compared to TEE. CMR measurements of AVA size were larger compared to TTE by an average of 10.7% (absolute difference: + 0.14cm2, 95% CI 0.07-0.21, p < 0.001). Reliability was high for both inter- and intra-observer measurements (0.03cm2 +/- 0.04 and 0.02cm2 +/- 0.01, respectively).

CONCLUSIONS

Our analysis demonstrates the equivalence of AVA measurements using CMR compared to those obtained using TEE. CMR demonstrated a small but significantly larger AVA than TTE. However, this can be attributed to known errors in derivation of left ventricular outflow tract size as measured by TTE. By offering additional anatomical assessment, CMR is warranted as a primary tool in the assessment and workup of patients with severe AS who are candidates for surgical or transcatheter intervention.