Remodeling classification system considering left ventricular volume in patients with aortic valve stenosis: Association with adverse cardiovascular outcomes

L-carnitine attenuated hyperuricemia-associated left ventricular remodeling through ameliorating cardiomyocytic lipid deposition

Hyperuricemia (HUA) is associated with left ventricular remodeling (LVR) and thereby causes the initiation and development of a large number of cardiovascular diseases. LVR is typically accompanied by cardiomyocyte energy metabolic disorder. The energy supply of cardiomyocytes is provided by glucose and fatty acid (FA) metabolism. Currently, the effect of HUA on cardiomyocytic FA metabolism is unclear. In this study, we demonstrate that UA-induced cardiomyocyte injury is associated with cytoplasmic lipid deposition, which can be ameliorated by the FA metabolism-promoting drug L-carnitine (LC). UA suppresses carnitine palmitoyl transferase 1B (CPT1B), thereby inhibiting FA transport into the mitochondrial inner matrix for elimination. LC intervention can ameliorate HUA-associated left ventricular anterior wall thickening in mice. This study showed that FA transport dysfunction plays is a critical mechanism in both cardiomyocytic injury and HUA-associated LVR and promoting cytoplasmic FA transportation through pharmacological treatment by LC is a valid strategy to attenuate HUA-associated LVR.

Surgical aortic valve replacement and left ventricular remodeling: Survival and sex-related differences

OBJECTIVES

To analyze how left ventricular (LV) remodeling and hypertrophy geometry evolve after surgical aortic valve replacement (SAVR) in octogenarian patients, and identify potential sex-related differences and implications for long-term outcomes.

METHODS

In 170 patients with aortic stenosis ([AS], age 80 ± 4 years, 59% women), hypertrophy geometry and remodeling (LV index) were reanalyzed one year post-SAVR. The six-year outcomes were evaluated.

RESULTS

Pre-SAVR, 65% of the women and 38.6% of the men (P < .001) showed adaptive remodeling. Concentric hypertrophy was prevalent in adaptive remodeling, and mixed and dilated hypertrophy were more prevalent in maladaptive remodeling. At one year, the remodeling patterns and sex distribution were similar to those observed pre-SAVR, but the LV index decreased in women and increased in men (P < .0001). Women with adaptive remodeling had a higher incidence of persistent concentric hypertrophy with higher LV filling pressures. Long-term survival was better in women and worse in men with adaptive remodeling (P = .039). Men with adaptive remodeling and men with concentric hypertrophy had the highest risk of cardiac death. This risk was similar between sexes for patients with maladaptive remodeling and dilated hypertrophy. Women with LV ejection fraction >55% had a lower risk of cardiac death than men.

CONCLUSIONS

The long-term outcomes of SAVR differ between sexes in older patients with AS and adaptive LV remodeling. The LV index facilitates studying the pathways of adaptation to AS. The follow-up shifts help explain the sex differences in long-term outcomes post-SAVR. Concentric hypertrophy is associated with the highest risk of cardiac death in men.

Clinical Value of Complex Echocardiographic Left Ventricular Hypertrophy Classification Based on Concentricity, Mass, and Volume Quantification

Echocardiography is the most validated, non-invasive and used approach to assess left ventricular hypertrophy (LVH). Alternative methods, specifically magnetic resonance imaging, provide high cost and practical challenges in large scale clinical application. To include a wide range of physiological and pathological conditions, LVH should be considered in conjunction with the LV remodeling assessment. The universally known 2-group classification of LVH only considers the estimation of LV mass and relative wall thickness (RWT) to be classifying variables. However, knowledge of the 2-group patterns provides particularly limited incremental prognostic information beyond LVH. Conversely, LV enlargement conveys independent prognostic utility beyond LV mass for incident heart failure. Therefore, a 4-group LVH subdivision based on LV mass, LV volume, and RWT has been recently suggested. This novel LVH classification is characterized by distinct differences in cardiac function, allowing clinicians to distinguish between different LV hemodynamic stress adaptations in various cardiovascular diseases. The new 4-group LVH classification has the advantage of optimizing the LVH diagnostic approach and the potential to improve the identification of maladaptive responses that warrant targeted therapy. In this review, we summarize the current knowledge on clinical value of this refinement of the LVH classification, emphasizing the role of echocardiography in applying contemporary proposed indexation methods and partition values.

Stimulus-effect relations for left ventricular growth obtained with a simple multi-scale model: the influence of hemodynamic feedback

Cardiac growth is an important mechanism for the human body to respond to changes in blood flow demand. Being able to predict the development of chronic growth is clinically relevant, but so far models to predict growth have not reached consensus on the stimulus–effect relation. In a previously published study, we modeled cardiac and hemodynamic function through a lumped parameter approach. We evaluated cardiac growth in response to valve disease using various stimulus–effect relations and observed an unphysiological decline pump function. Here we extend that model with a model of hemodynamic feedback that maintains mean arterial pressure and cardiac output through adaptation of peripheral resistance and circulatory unstressed volume. With the combined model, we obtain stable growth and restoration of pump function for most growth laws. We conclude that a mixed combination of stress and strain stimuli to drive cardiac growth is most promising since it (1) reproduces clinical observations on cardiac growth well, (2) requires only a small, clinically realistic adaptation of the properties of the circulatory system and (3) is robust in the sense that results were fairly insensitive to the exact choice of the chosen mechanics loading measure. This finding may be used to guide the choice of growth laws in more complex finite element models of cardiac growth, suitable for predicting the response to spatially varying changes in tissue load. Eventually, the current model may form a basis for a tool to predict patient-specific growth in response to spatially homogeneous changes in tissue load, since it is computationally inexpensive.

Staging Cardiac Damage in Patients With Hypertension

Ventricular and extraventricular response to pressure overload may be a common process in aortic stenosis and hypertension. We aimed to evaluate the association of a newly defined staging classification characterizing the extent of cardiac damage, originally developed for aortic stenosis, with long-term outcomes in patients with hypertension. We retrospectively analyzed 1639 patients with hypertension who had undergone both scheduled transthoracic echocardiography and electrocardiography in 2013 in a Japanese hospital, after excluding severe and moderate aortic stenosis, aortic regurgitation, mitral stenosis, previous myocardial infarction, or cardiomyopathy. We classified patients according to the presence or absence of cardiac damage as detected on echocardiography as follows: stage 0, no cardiac damage (n=858; 52.3%); stage 1, left ventricular damage (n=358; 21.8%); stage 2, left atrial or mitral valve damage (n=360; 22.0%); or stage 3 and 4, pulmonary vasculature, tricuspid valve, or right ventricular damage (n=63; 3.8%). The primary outcome was a composite of all-cause death and major adverse cardiac events. Cumulative 3-year incidence of the primary outcome was 15.5% in stage 0, 20.7% in stage 1, 31.8% in stage 2, and 60.6% in stage 3. After adjusting for confounders, the stage was incrementally associated with higher risk of the primary outcome (per 1-stage increase: hazard ratio, 1.46 [95% CI, 1.31–1.61]; P <0.001). The staging classification characterizing the extent of cardiac damage, originally developed for aortic stenosis, was associated with long-term outcomes in patients with hypertension in a stepwise manner.