Influence of hypertension on systolic and diastolic left ventricular function including segmental strain and strain rate.

BACKGROUND: Left ventricular (LV) systolic and diastolic functions are important cardiovascular risk predictors in patients with hypertension. However, data on segmental, layer-specific strain, and diastolic strain rates in these patients are limited. The aim of this study was to investigate segmental two-dimensional strain rate imaging (SRI)-derived parameters to characterize LV systolic and diastolic function in hypertensive individuals compared with that in normotensive individuals. METHODS: The study sample comprised 1194 participants from the population-based Know Your Heart study in Arkhangelsk and Novosibirsk, Russia, and 1013 individuals from the Seventh Tromsø Study in Norway. The study population was divided into four subgroups: (A) healthy individuals with normal blood pressure (BP), (B) individuals on antihypertensive medication with normal BP, (C) individuals with systolic BP 140-159 mmHg and/or diastolic BP > 90 mm HG, and (D) individuals with systolic BP ≥160 mmHg. In addition to conventional echocardiographic parameters, global and segmental layer-specific strains and strain rates in early diastole and atrial contraction (SR E, SR A) were extracted. The strain and SR (S/SR) analysis included only segments without strain curve artifacts. RESULTS: With increasing BP, the systolic and diastolic global and segmental S/SR gradually decreased. SR E, a marker of impaired relaxation, showed the most distinctive differences between the groups. In normotensive controls and the three hypertension groups, all segmental parameters displayed apico-basal gradients, with the lowest S/SR in the basal septal and highest in apical segments. Only SR A did not differ between the segmental groups but increased gradually with increasing BP. End-systolic strain showed incremental epi-towards endocardial gradients, irrespective of the study group. CONCLUSION: Arterial hypertension reduces global and segmental systolic and diastolic left ventricular S/SR parameters. Impaired relaxation determined by SR E is the dominant factor of diastolic dysfunction, whereas end-diastolic compliance (by SR A) does not seem to be influenced by different degrees of hypertension. Segmental strain, SR E and SR A provide new insights into the LV cardio mechanics in hypertensive hearts.

Novel approach to artefact detection and the definition of normal ranges of segmental strain and strain-rate values.

AIMS: Strain artefacts are known to hamper the correct interpretation of segmental strain and strain-rate (S/SR). Defining the normal ranges of myocardial segmental deformation is important in clinical studies and routine echocardiographic practice. In order to define artefact-free normal ranges for segmental longitudinal S/SR parameters, we investigated the extent to which different types of artefacts and their segmental localisation in the three different myocardial layers created a bias in the results of echocardiographic strain measurements. METHODS: The study included echocardiograms from men and women aged 40-69 years from two population-based studies, namely the Know Your Heart study (Russia) and the Tromsø Study (Norway). Of the 2207 individuals from these studies, 840 had normal results, defined as the absence of hypertension or indicators of any cardiovascular disease. Two-dimensional (2D) global and segmental S/SR of the three myocardial layers were analysed using speckle tracking echocardiography. Artefacts were assessed with two different methods: visual identification of image-artefacts and a novel conceptual approach of 'curve-artefacts' or unphysiological strain-curve formation. RESULTS: Segmental strain values were found to have significantly reduced in the presence of strain-curve artefacts (14.9%±5.8% towards -20.7%±4.9%), and increased with the foreshortening of the 2D image. However, the individual global strain values were not substantially altered by discarding segmental artefacts. Reduction due to artefacts was observed in all segments, layers, systolic and diastolic strain, and SR. Thus, we presented normal ranges for basal-septal, basal, medial and apical segment groups after excluding artefacts. CONCLUSION: Strain-curve artefacts introduce systematic errors, resulting in reduced segmental S/SR values. In terms of artefact-robust global longitudinal strain, the detection of curve-artefacts is crucial for the correct interpretation of segmental S/SR patterns. Intersegmental S/SR gradients and artefacts need to be considered for the correct definition of normalcy and pathology.

Echocardiographic assessment of diastolic dysfunction in elderly patients with severe aortic stenosis before and after aortic valve replacement.

BACKGROUND: The 2016 guidelines of the American Society of Echocardiography (ASE) and European Association of Cardiovascular Imaging (EACVI) for evaluation of left ventricular (LV) diastolic dysfunction by Doppler flow and tissue Doppler- echocardiography do not adjust assessment of high filling pressures for patients with aortic stenosis (AS). However, most of the studies on this patient group indicate age independent specific diastolic features in AS. The aim of this study is to identify disease-specific range and distribution of diastolic functional parameters and their ability to identify high N-terminal prohormone of brain natriuretic peptide (NT-proBNP) levels as a marker for high filling pressures. METHODS: In this study, 169 patients who underwent surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) were prospectively enrolled. Resting echocardiography was performed including Doppler of the mitral inflow, pulmonary venous flow, tricuspid regurgitant flow and tissue Doppler in the mitral ring and indexed volume-estimates of the left atrium (LAVI). Echocardiography, and NT-proBNP levels were assessed before TAVR/SAVR and at two postoperative visits at 6 and 12 months. RESULTS: Pre- and postoperative values were septal e'; 5.1 ± 3.9, 5.2 ± 1.6 cm/s; lateral e' 6.3 ± 2.1; 7.7 ± 2.7 cm/s; E/e'19 ± 8; 16 ± 7 cm/s; E velocity 96 ± 32; 95 ± 32 cm/s; LAVI 39 ± 8; 36 ± 8 ml/m2, pulmonary artery pressure (PAP) 39 ± 8; 36 ± 8 mmHg, respectively. The scoring recommended by ASE/EACVI detected elevated NT pro-BNP with a specificity of 25%. Adjusting thresholds towards PAP ≥ 40 mmHg, E velocity ≥ 100 cm/s, E deceleration time < 220 ms, and E/septal e' ≥ 20 or septal e' < 5.0 cm/s increased prediction of NT-proBNP levels ≥500 ng/L with substantially improved specificity (> 85%). CONCLUSION: Diastolic echocardiographic parameters in AS indicate persistent impaired relaxation and NT-proBNP indicate elevated filling pressures in most of the patients, improving only modestly 6-12 months after TAVR and SAVR. Applying the 2016 ASE/EACVI recommendations for detection of elevated filling pressures to patients with AS, elevated NT pro-BNP levels could not be reliably detected. However, adjusting thresholds of the echocardiographic parameters increased specificities to useful diagnostic levels. TRIAL REGISTRATION: The study was prospectively approved by the regional ethical committee, REK North with the registration number: REK 2010/397-10 .