Cardiac computed tomography for left ventricular remodeling assessment: does it mean echocardiography moves for the past?

Left ventricular hypertrophy (LVH) either detected by ECG or by echocardiography is well known to be a negative prognostic marker [1–3]. Later, pattern of left ventricular (LV) remodeling in hypertension were proposed as additional important prognostic factor [4]. Classification for concentric and eccentric LVH (CLVH and ELVH, respectively) as well as concentric remodeling and normal geometry was introduced according to echocardiography studies [5]. This classification based on assessment of LV size and relative wall thickness is widely used in clinical studies and even included into ESC/ESH Hypertension Guidelines and Echocardiography Guidelines [6,7]. Recently, the classification was reassessed by Khouri et al. [8], and it was demonstrated that ELVH with LV dilatation can be associated with poor prognosis, even worse than CLVH [9]. Up to the present, no ideal methodology for detection of LV remodeling pattern exists. Echocardiography is a well described method, which can be routinely applied in the majority of countries and is accepted to be a valuable cost/effective strategy [10]. However, the method is time-consuming and has imperfect reproducibility as well as significant interobserver variability. Cardiac MRI can be considered a gold standard for LV mass measurement, but poor availability and high cost result in lack of wide implementation in clinical practice. Thus, being well described and clear for research projects, LV remodeling patterns are routinely not evaluated in patients. In this issue of the Journal of Hypertension, Fuchs et al.[11] investigated LV remodeling pattern from the Copenhagen General Population Study. Authors performed analysis of LV remodeling based on relatively new methodology –cardiac computed tomography (CT) and included also left atrium morphology assessment. This is the first study that attempts to implement CT scans for cardiac geometry population screening. The obvious advantage of the study is a population-based large study sample. The major weak point is a lack of echocardiography performed in parallel, what does not allow comparing data with other studies aimed to reveal LV pattern prevalence especially in hypertension of different stages and grades. Authors found that chamber abnormalities were present in 23% in the population, with concentric remodeling being the more prevalent pattern (10%), which is significantly higher compared with echocardiography-based prevalence in comparable populations [12]. What is also untypical and unclear is that LV and RV enlargements appeared unrelated to hypertension in this study. Pilot studies of the same investigator's group showed a correlation between MRI and CT measurements of LV size and thickness [13,14]. Although the study applies the same methodology for pattern distinguishing as echocardiography does, it seems unlikely that LV geometry assessment done by CT can substitute echocardiography, and we can use the same classification and risk-stratification without pre-specified outcome studies. CT method is also relatively expensive and requires contrast investigation which can be limitations for future wide implementation. Authors made a very trivial conclusion about a strong link between elevated blood pressures and development of hypertension-mediated organ damage (HMOD). However, two interesting findings were obtained. First, enlargement of left atrium in 3–5% of the population was documented, which was not definitely associated with LV remodeling. Unfortunately, the method cannot assess cardiac fibrosis and diastolic dysfunction as a possible cause of LA dilatation. Second, relation between prevalence of HMOD and BP control in the population was documented. Despite general belief that better control of BP should result in less target organ damage, this fact was not demonstrated in large studies. LVH regression is shown to be associated with improved outcome; however, less is known about achieved BP control in the population and cardiac remodeling [15,16]. Our group more than 15 years ago but only in a small cohort of hypertensive patients had shown that long-term BP control can result in not only LVH regression but changes of the LV [17]. In 2018, changes of geometry patterns were in detail described in patients on medication but relation to BP control was not analyzed [18]. Despite several study limitations, it appears to be the first demonstration that cardiac CT can be useful for quick and precise assessment of LVH and LA size and used for large patient cohorts as a possible risk assessment method. Accumulation of sufficient new data and comparison of prognostic value can become a base for CT technology implementation in routine risk measurement of left ventricle size and structure, especially in the time of CT's growing role and frequency for calcification scoring. ACKNOWLEDGEMENTS Conflicts of interest There are no conflicts of interest.