Calibrated integrated backscatter and myocardial fibrosis in patients undergoing cardiac surgery

Abstract

ObjectiveThe reported association between calibrated integrated backscatter (cIB) and myocardial fibrosis is based on study of patients with dilated or hypertrophic cardiomyopathy and extensive (mean 15–34%) fibrosis. Its association with lesser degrees of fibrosis is unknown. We examined the relationship between cIB and myocardial fibrosis in patients with coronary artery disease.MethodsMyocardial histology was examined in left ventricular epicardial biopsies from 40 patients (29 men and 11 women) undergoing coronary artery bypass graft surgery, who had preoperative echocardiography with cIB measurement.ResultsTotal fibrosis (picrosirius red staining) varied from 0.7% to 4%, and in contrast to previous reports, cIB showed weak inverse associations with total fibrosis (r=−0.32, p=0.047) and interstitial fibrosis (r=−0.34, p=0.03). However, cIB was not significantly associated with other histological parameters, including immunostaining for collagens I and III, the advanced glycation end product (AGE) Nε-(carboxymethyl)lysine (CML) and the receptor for AGEs (RAGE). When biomarkers were examined, cIB was weakly associated with log plasma levels of amino-terminal pro-B-type natriuretic peptide (r=0.34, p=0.03), creatinine (r=0.33, p=0.04) and glomerular filtration rate (r=−0.33, p=0.04), and was more strongly associated with log plasma levels of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) (r=0.44, p=0.01) and soluble RAGE (r=0.53, p=0.002).ConclusionsHigher cIB was not a marker of increased myocardial fibrosis in patients with coronary artery disease, but was associated with higher plasma levels of sVEGFR-1 and soluble RAGE. The role of cIB as a non-invasive index of fibrosis in clinical studies of patients without extensive fibrosis is, therefore, questionable.

Myocardial tissue characterisation using echocardiographic deformation imaging

“…There was also a weak correlation found in a port-mortem study between atrial backscatter measurements and atrial interstitial area [44]. However, backscatter has limited ability to reflect fibrosis in those with lower levels of myocardial fibrosis, such as coronary artery disease [45]. Although there are modest relationships between backscatter and STE deformation measures [46], backscatter has major limitations compared to STE: the need for an intrinsic reference frame, the actual position of the sample volume, the limited validated views, the effect of image setting and the presence of artifacts and other reflectors [17].…”

Quantitative evaluation of myocardial fibrosis by cardiac integrated backscatter analysis in Kawasaki disease

“…Moreover, calibrated integrated backscatter has been used to quantitatively evaluate the echogenicity of the heart in Kawasaki disease [ 13 – 16 ]. Recently, it is questionable about the role of calibrated integrated backscatter as a non-invasive index of fibrosis in clinical studies of patients without extensive fibrosis such as coronary artery disease [ 17 ].…”

Myocardial Tissue Characterization and Fibrosis by Imaging

“…This technique can be thought of as palpating the tissues virtually using ultrasound (15). Although there is some correlation between calibrated integrated backscatter and fibrosis in patients with extensive myocardial fibrosis, this relationship is less clear in patients with milder degrees of fibrosis (16). Shear wave elasticity imaging can also detect dynamic stiffness changes during the cardiac cycle (15) Bone scintigraphy ( Figure 2) using 99mTc-labeled 3,3-diphosphono-1,2propanodicarboxylic acid (DPD), 99mTc-labeled pyrophosphate (PYP), and 99mTclabeled hydroxymethylene diphosphonate (HMDP) is highly sensitive for imaging cardiac transthyretin (ATTR) amyloidosis (22).…”