Layer-specific strain analysis of left ventricular myocardium after alcohol septal ablation for hypertrophic obstructive cardiomyopathy

Layer-specific strain echocardiography may reflect regional myocardial impairment in patients with hypertrophic cardiomyopathy

Our study aimed to determine whether layer-specific strain (LSS) could reflect regional myocardial impairment in patients with hypertrophic cardiomyopathy (HCM). The study enrolled 50 patients with HCM and 30 age-matched healthy controls. Transmural gradient of longitudinal strain (TGLS), defined as the difference between the longitudinal strain of the endocardium and epicardium in a left ventricular segment, was used to reflect layer-specific myocardial impairment. Negative TGLS was consistently observed in healthy controls. The TGLS was relatively consistent within the basal, middle, and apical levels in healthy controls,but showed a significant gradient from the base towards the apex. In patients with HCM, the hypertrophic segments had significantly higher TGLS than the relatively normal segments or healthy controls at all 3 levels (0.14 % ± 3.48 % vs. -2.65 % ± 4.44 % vs. -2.17 % ± 1.66 % for basal, - 0.72 % ± 3.71 % vs. -4.02 % ± 4.00 % vs. -3.58 % ± 2.29 % for middle, and - 8.69 % ± 7.96 % vs. -11.44 % ± 6.65 % vs. -10.04 % ± 3.20 % for apex). Abnormal TGLS, defined as positive TGLS, in patients with HCM was associated with chest pain. In receiver operating characteristic curve analysis, a large area of abnormal TGLS (> 4 segments) had moderate accuracy for predicting chest pain (sensitivity, 73.3 %; specificity, 70.0 %). TGLS, a novel LSS derived parameter, may reflect regional myocardial impairment in patients with HCM.

Reverse remodeling after percutaneous transluminal septal myocardial ablation in severe but asymptomatic LVOT obstruction (RASTA) study: Rationale and design of transcatheter septal reduction in asymptomatic patients with severe hypertrophic obstructive cardiomyopathy

OBJECTIVES

The aim of this study is to evaluate the impact of percutaneous transluminal septal myocardial ablation (PTSMA) on remodeling in asymptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) and severe left ventricular outflow tract (LVOT) obstruction.

BACKGROUND

Symptoms justify invasive treatment in HOCM patients with LVOT obstruction. Adverse structural and functional changes (remodeling) in the heart occur preceding heart failure and sudden cardiac death. Early invasive treatment in asymptomatic patients may reverse adverse remodeling to the same extent as in symptomatic patients.

METHODS

Reverse remodeling after PTSMA in severe but asymptomatic LVOT obstruction (RASTA) study is a prospective single-blind randomized trial (ClinicalTrials.gov number: NCT04230551). Ten asymptomatic HOCM patients with an exertional LVOT gradient ≥50 mmHg (or >30 mmHg in rest) are randomized 1:1 to PTSMA versus conservative therapy, in the absence of mitral valve disease or other indications for cardiac surgery. Five symptomatic (reference group) will undergo PTSMA according to the current guidelines.

RESULTS

Remodeling is assessed using extensive cardiac imaging with transthoracic echocardiography and late gadolinium enhancement cardiac magnetic resonance at baseline and during follow-up at 1, 12, and 24 months. Extracellular volume fraction, global, and regional strain analysis, geometry, pressure gradients and changes in four-dimensional velocity mapping are primary parameters to study (reversal of) adverse remodeling.

CONCLUSIONS

The RASTA study gives insight in cardiac remodeling that may occur in asymptomatic patients after PTSMA. It will provide arguments whether to pursue (or not) a larger trial with clinical endpoints in asymptomatic HOCM patients with severe LVOT obstruction.

Does layer-specific strain using speckle tracking echocardiography improve the assessment of left ventricular myocardial deformation? A review

An increasing number of studies of left ventricular myocardial deformation have been published. Layer-specific strain using speckle tracking echocardiography to evaluate left ventricular function is not recommended in clinical practice. However, evaluation of myocardial mechanics using longitudinal and circumferential layer-specific strain enables the detection of subclinical impairment of myocardial deformation in various diseases. Unfortunately, normal values for longitudinal and circumferential strain have not been clearly defined. In normal subjects, layer-specific strain decreases from the endocardial to the epicardial layer, and from the apex to the base of the left ventricle. Although various studies have tried to define normal values for each layer in healthy subjects, studies with more subjects are needed. This tool has good reproducibility in terms of intraobserver and interobserver variability, but, as with monolayer strain, it has poor intervendor variability. Efforts that aim for standardization between vendors will be required before widespread use of this technique can be advocated.

Echocardiographic reference ranges for normal left ventricular layer-specific strain: results from the EACVI NORRE study

AIMS

To obtain the normal range for 2D echocardiographic (2DE) measurements of left ventricular (LV) layer-specific strain from a large group of healthy volunteers of both genders over a wide range of ages.

METHODS AND RESULTS

A total of 287 (109 men, mean age: 46 ± 14 years) healthy subjects were enrolled at 22 collaborating institutions of the EACVI Normal Reference Ranges for Echocardiography (NORRE) study. Layer-specific strain was analysed from the apical two-, three-, and four-chamber views using 2DE software. The lowest values of layer-specific strain calculated as ±1.96 standard deviations from the mean were -15.0% in men and -15.6% in women for epicardial strain, -16.8% and -17.7% for mid-myocardial strain, and -18.7% and -19.9% for endocardial strain, respectively. Basal-epicardial and mid-myocardial strain decreased with age in women (epicardial; P = 0.008, mid-myocardial; P = 0.003) and correlated with age (epicardial; r = -0.20, P = 0.007, mid-myocardial; r = -0.21, P = 0.006, endocardial; r = -0.23, P = 0.002), whereas apical-epicardial, mid-myocardial strain increased with the age in women (epicardial; P = 0.006, mid-myocardial; P = 0.03) and correlated with age (epicardial; r = 0.16, P = 0.04). End/Epi ratio at the apex was higher than at the middle and basal levels of LV in men (apex; 1.6 ± 0.2, middle; 1.2 ± 0.1, base 1.1 ± 0.1) and women (apex; 1.6 ± 0.1, middle; 1.1 ± 0.1, base 1.2 ± 0.1).

CONCLUSION

The NORRE study provides useful 2DE reference ranges for novel indices of layer-specific strain.