Summary
Background
Right ventricular (RV) hypertrophy and RV systolic dysfunction are predictors of poor outcome. No study has investigated RV deformation and function in hypertensive patients with different left ventricular (LV) geometry patterns.
Aim
To investigate RV deformation and function in hypertensive patients with different LV geometric patterns, by using two-dimensional (2D) strain analysis and three-dimensional (3D) echocardiography.
Methods
This cross-sectional study included 184 hypertensive subjects, all of whom underwent complete 2D and 3D examinations. The participants were separated into two groups (with and without LV hypertrophy [LVH]), and were then divided into four further groups according to different LV geometry patterns: normal LV geometry, concentric remodelling, eccentric LVH and concentric LVH.
Results
Patients with LVH had significantly higher RV end-diastolic and end-systolic volume indexes and stroke volumes than those without LVH. Conversely, 3D RV ejection fraction was lower among subjects with LVH. 3D RV volume indexes gradually increased from subjects with normal LV geometry to those with concentric LVH, whereas 3D RV ejection fraction progressively decreased in the same direction. Global RV longitudinal strain was significantly lower in LVH subjects than in patients without LVH. 2D RV mechanics progressively deteriorated from patients with normal LV geometry to those with concentric LVH. Eccentric and concentric LVH were associated with reduced longitudinal lateral wall RV strain and early diastolic strain rate.
Conclusions
2D RV myocardial deformation and 3D RV function are affected significantly by LV geometry in hypertensive patients. Concentric and eccentric LVH patterns have the greatest unfavourable effect on RV deformation.
Résumé
Justification
L’hypertrophie et la dysfonction systolique ventriculaire droite sont des prédicteurs de mauvais pronostic. Il n’y a pas d’étude évaluant le retentissement de la déformation et de la dysfonction ventriculaire droite chez les patients hypertendus ayant différents aspects de géométrie ventriculaire gauche.
Objectifs
Investiguer la déformation (Speckle) et la fonction ventriculaire droite (VD) chez les patients hypertendus ayant différents aspects de géométrie ventriculaire gauche, en utilisant l’échographie 2D avec analyse de la déformation ainsi que l’échographie tridimensionnelle temps réel.
Méthode
Cette étude transversale a inclus 184 patients hypertendus qui ont tous bénéficié d’une échocardiographie bidimensionnelle et 3D. Les participants ont été scindés en deux groupes, avec et sans hypertrophie ventriculaire gauche (HVG) et ont été secondairement divisés en 4 groupes en fonction de la géométrie ventriculaire gauche : normal, remodelage concentrique, HVG excentrique et HVG concentrique.
Résultats
Les patients ayant une HVG ont un volume indexé télédiastolique et télésystolique VD ainsi qu’un volume d’éjection systolique significativement plus importants en l’absence d’HVG. Par ailleurs, la FEVD en échographie tridimensionnelle est plus faible chez les patients ayant une HVG. L’index de volume VD en 3D augmente graduellement depuis la morphologie normale jusqu’à l’HVG concentrique, tandis que la FEVD en 3D diminue de façon parallèle. La déformation longitudinale globale VD est significativement plus basse chez les patients ayant une HVG, comparativement à ceux n’ayant pas d’HVG. Les paramètres mécaniques VD en échographie 2D se dégradent progressivement depuis la géométrie normale jusqu’à l’HVG concentrique. HVG excentrique et concentrique sont associées avec une réduction du strain longitudinal de la paroi latérale du VD, ainsi qu’au strain protodiastolique.
Conclusion
La déformation myocardique VD en 2D et en 3D ainsi que la fonction VD sont affectées de façon significative par la géométrie ventriculaire gauche chez des patients hypertendus. HVG concentrique et excentrique ont les effets les plus défavorables sur le paramètre de déformation VD.
Background
The importance of left ventricular (LV) geometry patterns was recognized decades ago; however, in the last few years, it seems that the assessment of LV geometry has become even more significant. Large investigations have demonstrated that LV geometry, especially LV hypertrophy (LVH), is an independent risk factor for coronary heart disease, heart failure, arrhythmias, stroke and other cardiovascular morbidity and mortality .
The Dallas Heart Study showed that subjects with concentric LVH had a lower LV ejection fraction and higher concentrations of N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide than subjects with eccentric LVH . Bang et al. demonstrated that patients with eccentric and concentric LVH had increased risks of all-cause and cardiovascular mortality compared with those with normal LV mass (LVM) . Recently published studies obtained similar results using LV diameter instead of LV volume, as a variable of LV dilatation .
The MESA study revealed that right ventricular (RV) hypertrophy is associated with a higher risk of heart failure or death in a population free of clinical cardiovascular disease at baseline . RV systolic dysfunction is a predictor of poorer outcome in patients with preserved ejection fraction or dilated cardiomyopathy . Recent investigations have shown that RV global strain is a good predictor of RV dysfunction and mortality after cardiac surgery . However, to our knowledge, no study has investigated RV deformation and function in hypertensive patients with different LV geometry patterns.
Our hypothesis is that RV remodelling follows LV remodelling across different LV geometric patterns in hypertensive patients. The purpose of this investigation was to evaluate RV deformation and function by two-dimensional (2D) speckle tracking and three-dimensional (3D) echocardiography in hypertensive subjects with various patterns of LV geometry.
Methods
This cross-sectional study enrolled 184 hypertensive subjects, recruited from patients who were sent from general practitioners to our hospital for an echocardiographic examination or 24 h ambulatory blood pressure monitoring. Arterial hypertension was diagnosed according to the current guidelines . Clinic blood pressure values were obtained at two separate visits, 3 weeks apart. Blood pressure was measured in the morning using a conventional sphygmomanometer, by taking the average value of two consecutive measurements in the sitting position, 10 min apart. Blood pressure was calculated as average values between all measurements.
Exclusion criteria were symptoms or signs of heart failure, coronary artery disease, previous cerebrovascular events, atrial fibrillation, congenital heart disease, valve heart disease (greater than mild), neoplastic disease, liver cirrhosis, kidney failure and endocrine diseases, including type 2 diabetes mellitus. Subjects with unsatisfactory 3D acquisitions (eight participants) were also excluded from further analyses.
Anthropometric measures (height, weight), data regarding smoking status and laboratory analyses (concentrations of fasting glucose, blood creatinine, total cholesterol and triglycerides) were obtained from all the subjects included in the study. Body mass index (BMI) and body surface area (BSA) were calculated for each patient. Obesity was defined as BMI ≥ 30 kg/m 2 . The study was approved by the local ethics committee. Informed consent was obtained from all the participants.
Echocardiography
Echocardiographic examinations were performed using a commercially available Vivid 7 ultrasound machine (GE Vingmed Ultrasound AS, Horten, Norway).
Reported values of all 2D variables were obtained as the average value of three consecutive cardiac cycles. LV end-diastolic (LVIDd) and end-systolic diameters, posterior wall thickness (PWT) and interventricular septum thickness (IVST) were measured according to the recommendations . Relative wall thickness (RWT) was calculated according to the formula: (2 × PWT)/LVIDd. The biplane method was used for determination of 2D LV end-diastolic and end-systolic volumes and calculation of ejection fraction. 2D LV volumes were indexed for BSA. LVM was calculated using the Penn formula: 1.04 × [(LVIDd + IVSTd + PWTd) 3 – LVIDd 3 ] – 13.6 , and indexed for height 2.7 (LVMI).
All subjects were divided into four LV geometry pattern groups: normal LV geometry (normal LVMI and RWT); concentric remodelling (normal LVMI and increased RWT); eccentric LVH (increased LVMI and normal RWT); and concentric LVH (increased LVMI and RWT). LVH was defined as LVMI ≥ 50 g/m 2.7 in men and ≥ 47 g/m 2.7 in women .
Left atrial volume was determined according to the biplane method in four- and two-chamber views, and indexed for BSA.
Pulsed-wave Doppler assessment of transmitral flow was obtained in the apical four-chamber view, according to the guidelines .
Right ventricle and atrium
The RV internal diameter was measured in the parasternal long-axis view . RV thickness was measured in the subcostal view. RV fractional area change (RV FAC) was measured from the apical four-chamber view. RV FAC was calculated using the formula: (end-diastolic area–end-systolic area)/end-diastolic area . Right atrial maximal volume was obtained in the four-chamber view during ventricular end-systole.
Tricuspid flow velocities were assessed by pulsed-wave Doppler in the apical four-chamber view. The following variables were determined: early diastolic peak flow velocity (E t ); late diastolic flow velocity (A t ); and their ratio (E/A) t . Tissue Doppler imaging was used to obtain RV myocardial velocities in the apical four-chamber view, with a sample volume placed at the lateral segment of the tricuspid annulus during early diastole (e’ t ) and systole (s t ) . The tricuspid (E/e’) t ratio was determined using previously estimated Doppler values.
RV global systolic function was assessed as the tricuspid annular plane systolic excursion (TAPSE) . RV systolic pulmonary artery pressure was assessed in patients with minimal/mild tricuspid regurgitation.
2D RV and atrial strain and strain rate
2D strain imaging was performed by using three consecutive cardiac cycles of 2D images in the apical four-chamber view . The commercially available EchoPAC 112 software (GE Healthcare, Horten, Norway) was used for the 2D strain analysis.
The variables that were used for evaluation of systolic function and contractility were longitudinal peak and systolic strain rate, respectively. The variables of early myocardial relaxation and late ventricular filling were estimated by early and late diastolic strain rate. Peak longitudinal strain and systolic and diastolic strain rates for the RV lateral wall and global RV were determined separately. Global RV longitudinal strain and strain rates were determined for the whole right ventricle (RV), including the interventricular septum, whereas longitudinal strain and corresponding strain rates for the RV lateral wall were assessed only for the RV free (lateral) wall in the four-chamber apical view.
3D echocardiographic acquisition
A full-volume acquisition of the RV for further analyses was obtained from an apical approach. Six electrocardiogram-gated consecutive beats were acquired during end-expiratory breath-hold to generate full volume. All data sets were analysed using the commercially available software RV TomTec (EchoPAC 112; GE Healthcare, Horten, Norway). We analysed RV volumes, RV stroke volume and RV ejection fraction. The frame rate was between 20 and 30 frames/s.
Statistical analysis
All variables were tested for normal distribution using the Kolmogorov-Smirnov test. Continuous variables are presented as means ± standard deviations and were compared by analysis of equal variance (ANOVA), as they showed normal distribution. Bonferroni post hoc analysis was used for the comparison between different groups. The differences in proportions were compared using the χ 2 test or Fisher’s exact test where appropriate. The correlations between RV global longitudinal strain and 3D RV volumes, RV wall thickness and RV systolic pressure were determined by Pearson’s correlation test. The associations between different LV geometry patterns and impaired 2D strain and strain rates, independent of age, BMI, systolic blood pressure, LVM, LV ejection fraction, pulmonary artery systolic pressure (PASP) and RV wall thickness, were determined by multivariable logistic regression (odds ratio [OR] and 95% confidence interval [CI]). Given the lack of guidelines regarding cut-off values for 2D strain and strain rate, we used meta-analysis data for RV lateral wall longitudinal strain , and data obtained from healthy subjects in our previous studies for systolic, early and late diastolic strain rates . A P value < 0.05 was considered statistically significant.
Results
Our findings showed that 105 hypertensive patients did not have LVH, whereas 79 patients had LVH ( Table 1 ). Additionally, we identified 80 patients with normal LV geometry, 25 with concentric LV remodelling, 45 with eccentric LVH and 34 with concentric LVH. The subjects with LVH were older, and had a higher BMI and BSA than non-LVH patients. There was no difference in sex distribution between LVH and non-LVH groups. Obesity was more prevalent among LVH subjects, who also had higher blood pressure, glucose and triglyceride concentrations than non-LVH individuals ( Table 1 ).
| No LVH | LVH | P | |||
|---|---|---|---|---|---|
| ( n = 105) | ( n = 79) | ||||
| Age (years) | 48 ± 7 | 53 ± 8 | < 0.001 | ||
| Women | 50 (48) | 40 (51) | 0.766 | ||
| Weight (kg) | 78.3 ± 12.3 | 84 ± 13.6 | 0.003 | ||
| Height (m) | 1.73 ± 0.10 | 1.74 ± 0.11 | 0.521 | ||
| BMI (kg/m 2 ) | 26.2 ± 3.3 | 27.7 ± 3.6 | 0.004 | ||
| BSA (m 2 ) | 1.94 ± 0.2 | 2.01 ± 0.19 | 0.017 | ||
| Obese patients | 10 (10) | 20 (25) | 0.005 | ||
| Smokers | 44 (42) | 33 (42) | 1.000 | ||
| Clinic systolic BP (mmHg) | 139 ± 12 | 148 ± 14 | < 0.001 | ||
| Clinic diastolic BP (mmHg) | 82 ± 8 | 88 ± 9 | < 0.001 | ||
| Antihypertensive drugs | 20 (19) | 43 (55) | < 0.001 | ||
| Plasma glucose (mmol/L) | 4.9 ± 0.8 | 5.4 ± 0.7 | < 0.001 | ||
| Triglycerides (mmol/L) | 1.7 ± 0.3 | 1.9 ± 0.4 | < 0.001 | ||
| Total cholesterol (mmol/L) | 5.2 ± 0.8 | 5.4 ± 1 | 0.134 |
| Normal LV geometry | Concentric LV remodelling | Eccentric LVH | Concentric LVH | P | |
|---|---|---|---|---|---|
| ( n = 80) | ( n = 25) | ( n = 45) | ( n = 34) | ||
| Age (years) | 48 ± 7 | 49 ± 7 | 51 ± 8 | 56 ± 8 b,d,e | < 0.001 |
| Women | 40 (50) | 10 (40) | 23 (51) | 17 (50) | 0.817 |
| Weight (kg) | 77.5 ± 11.6 | 79.5 ± 13.8 | 83.6 ± 13 | 84 ± 12.3 a | 0.018 |
| Height (m) | 1.73 ± 0.10 | 1.73 ± 0.09 | 1.74 ± 0.11 | 1.73 ± 0.10 | 0.954 |
| BMI (kg/m 2 ) | 25.9 ± 3.3 | 26.8 ± 3.2 | 27.6 ± 3.1 a | 28.1 ± 3.6 b | 0.005 |
| BSA (m 2 ) | 1.93 ± 0.2 | 1.96 ± 0.18 | 2.01 ± 0.19 | 2.01 ± 0.18 | 0.076 |
| Obese patients | 4 (5) | 6 (24) | 11 (24) b | 14 (41) b | < 0.001 |
| Smokers | 34 (43) | 10 (40) | 18 (40) | 15 (44) | 0.980 |
| Clinic systolic BP (mmHg) | 138 ± 11 | 141 ± 14 | 146 ± 12 b | 151 ± 14 b,c | < 0.001 |
| Clinic diastolic BP (mmHg) | 82 ± 8 | 83 ± 7 | 87 ± 8 b | 89 ± 9 b,c | < 0.001 |
| Antihypertensive drugs | 14 (18) | 6 (24) | 20 (44) b | 23 (68) b,d | < 0.001 |
| Plasma glucose (mmol/L) | 4.8 ± 0.8 | 5 ± 0.6 | 5.3 ± 0.7 b | 5.5 ± 0.7 b | < 0.001 |
| Triglycerides (mmol/L) | 1.7 ± 0.3 | 1.8 ± 0.4 | 1.8 ± 0.3 | 2 ± 0.4 b | < 0.001 |
| Total cholesterol (mmol/L) | 5.1 ± 0.8 | 5.3 ± 0.8 | 5.3 ± 0.9 | 5.5 ± 1.1 | 0.161 |
a P < 0.05 versus normal LV geometry.
b P < 0.01 versus normal geometry.
c P < 0.05 versus concentric remodelling.
d P < 0.01 versus concentric remodelling.
Patients with concentric LVH were older than the other hypertensive subjects ( Table 1 ). There was no sex difference between the groups. BMI was higher in eccentric and concentric LVH groups than in normal LV geometry subjects. There was no difference in prevalence of smokers between the observed groups. Eccentric and concentric LVH groups had significantly more obese subjects than the normal LV geometry group. Despite the fact that the percentage of treated subjects was higher among patients with eccentric and concentric LVH, blood pressure values were still higher in these groups than in the other groups ( Table 1 ). Glucose concentrations were lower in subjects with normal LV geometry than in those with eccentric and concentric LVH, while triglyceride concentrations were higher in the concentric LVH group than in those with normal LV geometry ( Table 1 ).
Conventional echocardiographic variables
LV end-diastolic diameter, RWT, LVM and LVMI were significantly higher among LVH subjects, as were LV and left atrial volumes ( Table 2 ). The mitral E/A ratio was significantly lower among LVH subjects. RV diameter and RV wall thickness were higher in LVH participants, which demonstrates RV structural remodelling in these subjects. Furthermore, the variables of RV systolic function (TAPSE, FAC, s t ) were lower in LVH patients ( Table 2 ). RV diastolic function indexes (tricuspid E/A and E/e’ ratios) had also deteriorated in LVH individuals.
