Impact of diastolic blood pressure on speckle tracking derived myocardial work components in a population of normotensive and untreated hypertensive patients
Authors: Lembo M , Santoro C , Casciano O , Capone V , Fedele T , Luciano F , Canonico M , Buonauro A , Esposito R , Galderisi M 
Published: November 2020

Abstract

Background
Arterial hypertension deeply influences left ventricular (LV) mechanics and global longitudinal strain (GLS). The effect of blood pressure (BP), in particular systolic BP burden, on speckle tracking derived myocardial work (MW) was demonstrated in both hypertensive and healthy subjects.

Purpose
Aim of our study was to evaluate the impact of diastolic BP (DBP) on MW components in a population of newly-diagnosed, never treated hypertensive patients and healthy subjects.

Methods
The study population included 105 newly-diagnosed, never treated hypertensive patients (M/F= 62/43; age=46.1±13.0 years, BP=145.1±10/89.8±7.4 mmHg), and 105 healthy normotensive subjects (BP=121.6±9.8/73.7±7.4mmHg), matched for age and sex. All participants underwent standard echo exam, including GLS evaluation (in absolute value). Cuff BP was employed as a surrogate of LV peak pressure for the assessment of global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE). Exclusion criteria were diabetes mellitus, coronary artery disease, overt heart failure, valve heart disease, primary cardiomyopathies, atrial fibrillation and inadequate echo imaging. The study population was divided into two groups according to DBP threshold of normalcy defined by 2018 ESH/ESC guidelines: the first group including individuals with normal DBP (n=135, DBP&lt;90mmHg) and the second group including patients with abnormal DBP (n=75, DBP ≥90 mmHg).

Results
The two groups were comparable for sex prevalence, age and heart rate. Body mass index (BMI), systolic and mean BP were higher in the group with abnormal DBP (all p&lt;0.0001). Among echo data, no significant intergroup difference was found in LV mass index, relative wall thickness, ejection fraction and diastolic parameters. GLS was lower in patients with abnormal DBP (20.4±1.9 vs. 22.1±2.1%, p&lt;0.0001). GWI (2443.0±403.1 vs. 2277.3±359.6 mmHg%, p&lt;0.002), GCW (2733.5±406.0 vs. 2556.9±405.6 mmHg%, p=0.003) and GWW (112.8±84.4 vs. 76.8±45.1 mmHg%, p&lt;0.0001) were significantly higher in patients with abnormal DBP, whereas GWE (95.3±2.8 vs. 96.2±1.7%, p&lt;0.002) was lower in this group. In the pooled population, DBP was positively related to GWI, GCW (both r=0.30, p&lt;0.0001) and GWW (r=0.26, p&lt;0.0001), while negatively correlated with GLS (r=−0.37, p&lt;0.0001) and GWE (r=−0.21, p&lt;0.002). By separate multiple linear regression analyses, GWI (β=0.45, p&lt;0.0001), GCW (β=0.47, p&lt;0.0001), GWW (β=0.20, p=0.007) and GWE (β=−0.15, p&lt;0.05) were all independently associated with DBP, after adjusting for male sex, age, BMI, heart rate, GLS and E/e' ratio.

Conclusions
In a population of untreated hypertensive patients and healthy subjects, increased DBP affects longitudinal function and MW. In particular, elevated diastolic BP induces an increase of wasted work which is only partially balanced by the increased constructive work, thus provoking a clear reduced efficiency of myocardial mechanics.
Figure 1

Funding Acknowledgement
Type of funding source: None