Severe aortic stenosis tied to adverse myocardial remodelling like poor myocardial flow reserve: JAMA

A group of researchers from U.S.A conducted a study to investigate whether MFR and stress MBF are associated with LV structure and function derangements and whether these parameters improve after aortic valve replacement (AVR).

In this single-centre prospective observational study in Boston, Massachusetts, from 2018 to 2020, patients with predominantly moderate to severe AS underwent ammonia N13 PET myocardial perfusion imaging for myocardial blood flow (MBF) quantification, resting transthoracic echocardiography (TTE) for assessment of myocardial structure and function, and measurement of circulating biomarkers for myocardial injury and wall stress. Evaluation of health status and functional capacity was also performed. A subset of patients underwent repeated assessment 6 months after AVR. A control group included patients without AS matched for age, sex, and summed stress score who underwent symptom-prompted ammonia N13 PET and TTE within 90 days.

LV structure and function parameters, including echocardiographic global longitudinal strain (GLS), circulating high-sensitivity troponin T (hs-cTnT), N-terminal pro–B-type natriuretic peptide (NT-pro BNP), health status, and functional capacity.

The results of the study are as follows:

· There were 34 patients with AS (1 mild, 9 moderate, and 24 severe) and 34 matched control individuals. MFR was independently associated with GLS and LV ejection fraction.

· Stress MBF was associated with hs-cTnT and log NT-pro BNP.

· The combination of low-stress MBF and high hs-cTnT was associated with higher interventricular septal thickness in diastole, relative wall thickness, and worse GLS compared with high-stress MBF and low hs-cTnT.

· In 9 patients studied 6 months after AVR, mean (SD) MFR improved from 1.73 (0.57) to 2.11 (0.50).

Thus, the researchers concluded that in AS, MFR and stress MBF were associated with adverse myocardial characteristics, including markers of myocardial injury and wall stress, suggesting that MFR may be an early sensitive marker for myocardial decompensation.

Reference:

Association of Myocardial Blood Flow Reserve With Adverse Left Ventricular Remodeling in Patients With Aortic Stenosis The Microvascular Disease in Aortic Stenosis (MIDAS) Study by Zhou W et. al published in the JAMA Cardiology.