Is left ventricular hypertrophy regression important? Does the tool used to detect it matter?

Plasma protein thiolation index (PTI) as a potential biomarker for left ventricular hypertrophy in humans

Background

Left ventricular hypertrophy (LVH) has been associated with oxidative stress, although not with the protein thiolation index (PTI). This study explored the potential use of PTI as a biomarker of oxidative stress in patients with LVH.

Methods

We recruited 70 consecutive patients (n = 35 LVH and n = 35 non-LVH) based on an echocardiography study in our institution (left ventricular mass indexed to body surface area). Plasma levels of both S-thiolated protein and total thiols were measured as biomarkers of oxidative stress by spectrophotometry, and PTI was calculated as the molar ratio between S-thiolated proteins and the total thiol concentration.

Results

Values for plasma S-thiolated proteins were higher in patients with LVH than in the control group (P = 0.01). There were no differences in total thiols between the LVH group and the control group. Finally, PTI was higher in patients with LVH than in the control group (P = 0.001). The area under the ROC curve was 0.75 (95% CI, 0.63–0.86; P<0.001), sensitivity was 70.6%, and specificity was 68.6%, thus suggesting that PTI could be used to screen for LVH. A multivariable logistic regression model showed a positive association (P = 0.02) between PTI and LVH (OR = 1.24 [95% CI, 1.03–1.49]) independently of gender (OR = 3.39 [95% CI, 0.60–18.91]), age (OR = 1.03 [95% CI, 0.96–1.10]), smoking (OR = 5.15 [95% CI, 0.51–51.44]), glucose (OR = 0.99 [95% CI, 0.97–1.01]), systolic arterial pressure (OR = 1.10 [CI 1.03–1.17]), diastolic arterial pressure (OR = 0.94 [CI 0.87–1.02]), dyslipidemia (OR = 1.46 [95% CI, 0.25–8.55]), estimated glomerular filtration rate (OR = 0.98 [95% CI, 0.96–1.01]), body mass index (OR = 1.03 [95% CI, 0.90–1.10]), and valvular and/or coronary disease (OR = 5.27 [95% CI, 1.02–27.21]).

Conclusions

The present study suggests that PTI could be a new biomarker of oxidative stress in patients with LVH.

Recommendations on the Use of Echocardiography in Adult Hypertension: A Report from the European Association of Cardiovascular Imaging (EACVI) and the American Society of Echocardiography (ASE)

Hypertension remains a major contributor to the global burden of disease. The measurement of blood pressure continues to have pitfalls related to both physiological aspects and acute variation. As the left ventricle (LV) remains one of the main target organs of hypertension, and echocardiographic measures of structure and function carry prognostic information in this setting, the development of a consensus position on the use of echocardiography in this setting is important. Recent developments in the assessment of LV hypertrophy and LV systolic and diastolic function have prompted the preparation of this document. The focus of this work is on the cardiovascular responses to hypertension rather than the diagnosis of secondary hypertension. Sections address the pathophysiology of the cardiac and vascular responses to hypertension, measurement of LV mass, geometry, and function, as well as effects of treatment.

Does the ADMA/DDAH/NO pathway modulate early regression of left ventricular hypertrophy with esmolol?

Hypertensive left ventricular hypertrophy (LVH) is a maladaptive response to chronic pressure overload and a strong independent risk factor for cardiovascular disease. Regression of LVH is associated with improved prognosis. Regression of LVH with antihypertensive therapy (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, calcium channel blockers, and diuretics) has been reported, although only after long-term treatment. Asymmetrical dimethylarginine (ADMA), the most potent endogenous NO synthase inhibitor, is emerging as an important cardiovascular risk factor in patients with arterial hypertension and LVH, and dimethylarginine dimethylaminohydrolase (DDAH) is the mechanism that most frequently leads to accumulation of ADMA (plasma ADMA is cleared in small part by renal excretion, although the bulk of ADMA is degraded by DDAH). Left ventricular mass is strongly modulated by the NO system. As an important inhibitor of the bioavailability of NO, ADMA is an underlying mechanism of LVH. Beta-blockers can induce regression of LVH and reduced plasma ADMA levels. Oxidative stress is increased in patients with LVH, and this in turn increases generation of ADMA. In a previous preclinical study of spontaneously hypertensive rats, we found that short-term treatment (48 h) with esmolol reverses early LVH, increases the bioavailability of NO, and improves antioxidant status in plasma. Therefore, we propose that the ADMA/DDAH/NO pathway could modulate early regression of LVH with esmolol.

Ex vivo cardiovascular magnetic resonance measurements of right and left ventricular mass compared with direct mass measurement in excised hearts after transplantation: a first human SSFP comparison

BACKGROUND

CMR is considered the 'gold standard' for non-invasive LV and RV mass quantitation. This information is solely based on gradient-recalled echo (GRE) sequences while contrast dependent on intrinsic T1/T2 characteristics potentially offers superior image contrast between blood and myocardium. This study aims, for the first time in humans, to validate the SSFP approach using explanted hearts obtained from heart transplant recipients. Our objective is establish the correlation between and to validate steady-state free precession (SSFP) derived LV and RV mass vs. autopsy mass of hearts from cardiac transplants patients.

METHODS

Over three-years, 58 explanted cardiomyopathy hearts were obtained immediately upon orthotopic heart transplantation from the OR. They were quickly cleaned, prepared and suspended in a saline-filled container and scanned ex vivo via SSFP-SA slices to define LV/RV mass. Using an automatic thresholding program, segmentation was achieved in combination with manual trimming (ATMT) of extraneous tissue incorporating 3D cardiac modeling performed by independent and blinded readers. The explanted hearts were then dissected with the ventricles surgically separated at the interventricular septum. Weights of the total heart not excluding papillary and trabecular myocardium, LV and RV were measured via high-fidelity scale. Linear regression and Bland-Altman plots were used to analyze the data. The intra-class correlation coefficient was used to assess intra-observer reliability.

RESULTS

Of the total of 58 explanted hearts, 3 (6%) were excluded due to poor image quality leaving 55 patients (94%) for the final analysis. Significant positive correlations were found between total 3D CMR mass (450 ± 111 g) and total pathology mass (445 ± 116 g; r = 0.99, p < 0.001) as well as 3D CMR measured LV mass (301 ± 93 g) and the pathology measured LV mass (313 ± 96 g; r = 0.95, p < 0.001). Strong positive correlations were demonstrated between the 3D CMR measured RV mass (149 ± 46 g) and the pathology measured RV mass (128 ± 40 g; r = 0.76, p < 0.001). The mean bias between 3D-CMR and pathology measures for total mass, LV mass and RV mass were: 3.0 g, -16 g and 19 g, respectively.

CONCLUSIONS

SSFP-CMR accurately determines total myocardial, LV and RV mass as compared to pathology weighed explanted hearts despite variable surgical removal of instrumentation (left and right ventricular assist devices, AICD and often apical core removals). Thus, this becomes the first-ever human CMR confirmation for SSFP now validating the distinction of 'gold standard'.

Visit-to-visit blood pressure variability, silent cerebral injury, and risk of stroke

Apart from the well-known role of hypertension in cerebrovascular disease, visit-to-visit blood pressure (BP) variability is emerging as an independent risk factor for stroke. Although the underlying mechanism is not fully understood, artery remodeling is thought to be closely involved in the relationship between visit-to-visit BP variability and stroke. This review article summarizes the recent literature on these topics. Silent cerebral injury is considered to serve as a common pathophysiology in the relationship of visit-to-visit BP variability with cognitive impairment and stroke. Here we review visit-to-visit BP variability, some comparisons of the effects of antihypertensive agents on visit-to-visit BP variability, and an issue regarding the impact of these agents on stroke.

Visit-to-visit and ambulatory blood pressure variability as predictors of incident cardiovascular events in patients with hypertension

BACKGROUND

Visit-to-visit blood pressure variability (BPV) has been shown to be a prognostic indicator in hypertensive patients. We designed this study to clarify the impacts of clinic and ambulatory BPV in predicting cardiovascular disease (CVD).

METHODS

We performed ambulatory BP monitoring (ABPM) in 457 hypertensive patients. Visit-to-visit BPV and ambulatory BPV were calculated as the SDs of clinic BP, awake BP, and sleep BP. The mean age of the subjects was 67.0 ± 9.2 years, and they were followed for 67 ± 26 months. Stroke, myocardial infarction, and sudden cardiac death were defined as Hard CVD events, and these plus angina, heart failure, and other CVDs were defined as All CVD events. Multivariable Cox hazard regression models predicting CVD events were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI) for different measures of BPV with adjustment for significant covariates.

RESULTS

In multivariable analyses, the BPV of clinic systolic BP (SBP) was an independent predictor for All CVD events (HR, 2.20; 95% CI, 1.25-3.88; P < 0.01), but not for Hard CVD events (P = 0.20). On the other hand, the BPV of sleep SBP was an independent predictor for Hard CVD events (HR, 2.21; 95% CI, 1.08-4.53; P = 0.03), but not for All CVD events (P = 0.88). Diastolic BPV exhibited the same pattern.

CONCLUSIONS

These findings suggest that visit-to-visit BPV and ambulatory BPV are separately useful in predicting cardiovascular outcomes.

Effects of the combinations of amlodipine/valsartan versus losartan/hydrochlorothiazide on left ventricular hypertrophy as determined with magnetic resonance imaging in patients with hypertension

BACKGROUND

Left ventricular hypertrophy (LVH), a marker of cardiac end-organ damage, is frequently found in patients with arterial hypertension and is associated with cardiovascular and cerebrovascular morbidity and mortality. Therefore, LVH regression is an important treatment goal. For amlodipine plus valsartan (A/V) no specific study on LVH has been reported to date.

METHODS

Prospective, open-label, randomized parallel-group study. Patients with essential hypertension and LVH were randomized to 52-week treatment with A/V 10/160 mg (n = 43) or the active comparator losartan/HCT 100/25 mg (L/H, n = 47). Add-on medication was allowed in case of inadequate blood pressure control. LV parameters were measured by cardiovascular magnetic resonance imaging (MRI), and adjudicated in a blinded manner. Study identifiers were NCT00446563 and EudraCT 2006-001977-17.

RESULTS

In addition to the study treatment, 35% of patients in the A/V group and 49% in the L/H group received additional antihypertensive medication. Compared to baseline, both treatments reduced measures of LVH significantly after 52 weeks (e.g. LV mass index in the A/V group from 64.7 g/m(2) by -3.5 g/m(2), in the L/H group from 69.1 g/m(2) by -4.4 g/m(2), p < 0.01 for both). LV ejection fraction and LV volumes were not significantly changed by any regimen. A/V and L/H treatments were well tolerated.

CONCLUSIONS

Both regimen were effective in reducing LV mass compared to baseline and were well tolerated.