Left ventricular hypertrophy: a “factor of risk”

Midlife blood pressure change and left ventricular mass and remodelling in older age in the 1946 British Birth Cohort Study

Aims

Antecedent blood pressure (BP) may contribute to cardiovascular disease (CVD) independent of current BP. Blood pressure is associated with left ventricular mass index (LVMI) which independently predicts CVD. We investigated the relationship between midlife BP from age 36 to 64 and LVMI at 60–64 years.

Methods and results

A total of 1653 participants in the British 1946 Birth Cohort underwent BP measurement and echocardiography aged 60–64. Blood pressure had previously been measured at 36, 43, and 53 years. We investigated associations between BP at each age and rate of change in systolic blood pressure (SBP) between 36–43, 43–53, and 53–60/64 years on LVMI at 60–64 years. Blood pressure from 36 years was positively associated with LVMI. Association with SBP at 53 years was independent of SBP at 60–64 years and other potential confounders (fully adjusted β at 53 years = 0.19 g/m²; 95% CI: 0.11, 0.27; P < 0.001). Faster rates of increase in SBP from 43 to 53 years and 53 to 60/64 years were associated with increased LVMI. Similar relationships were seen for diastolic, pulse, and mean pressure. Rate of increase in SBP between 43–53 years was associated with largest change in LVMI (β at 43–53 years = 3.12 g/m²; 95% CI: 1.53, 4.72; P < 0.001). People on antihypertensive medication (43 years onwards) had greater LVMI even after adjustment for current BP (β at 43 years = 12.36 g/m²; 95% CI: 3.19, 21.53; P = 0.008).

Conclusion

Higher BP in midlife and rapid rise of SBP in 5th decade is associated with higher LVMI in later life, independent of current BP. People with treated hypertension have higher LVMI than untreated individuals, even accounting for their higher BP. Our findings emphasize importance of midlife BP as risk factor for future CVD.

Hypertensive renal vascular disease and cardiovascular endpoints

PURPOSE OF REVIEW

Hypertension involves the entire cardiovascular system, and hypertensive vascular disease may promote and exacerbate cardiac and renal dysfunction. We discuss the coexistence of cardiorenal disease as a manifestation of vascular involvement in hypertension, and the relationship of biomarkers of renal vascular involvement in hypertension with cardiovascular endpoints.

RECENT FINDINGS

Markers of renal dysfunction, especially microalbuminuria, have been considered recently as potent predictors of cardiovascular morbidity and mortality in all explored populations, including hypertensive individuals. Microalbuminuria, per se, is related to vascular injury and to the increased glomerular permeability of albumin as a direct manifestation of renal vascular involvement in hypertension, a systemic vascular disease. Left ventricular hypertrophy in hypertension develops even before proteinuria or impairment of renal function. Factors including anemia, inflammation and hyperuricemia are either induced or exacerbated by renal vascular disease, and each of these may exert additional influence in determining the increased incidence of cardiovascular events with progressive renal dysfunction.

SUMMARY

The development and progression of vascular disease is the primary determinant in the progressive cardiac and renal dysfunction observed in hypertension and, therefore, is the underlying mechanism of the overall clinical manifestations of cardiorenal disease. Commonly used biomarkers of renal and vascular function are important tools for determination of the progression and, hence, management of hypertensive disease and its complications.

Prevalence and determinants of electrocardiographic left ventricular hypertrophy among a multiethnic population of postmenopausal women (The Women's Health Initiative)

Our objectives were to determine the prevalence and factors related to left ventricular hypertrophy (LVH) among older women for commonly used electrocardiographic criteria. LVH is a potent risk factor for cardiovascular disease, especially among women. However, its value has been limited, in part, by the use of different electrocardiographic criteria and the lack of a clearly defined standard for the general population. A total of 3,613 eligible women, aged 50 to 79 years, underwent medical history, physical measurements, and biochemical determinations and had behavioral factors recorded at baseline. Three LVH indexes were derived from computer measurement of the electrocardiogram: hypertrophied left ventricular mass > or =171.04 g (HLVM); Cornell voltage > or =2,200 microV; and Minnesota Code items. The prevalence of LVH ranged from <1% to 13% when stratified by age, ethnicity, and scoring technique. Baseline traits differed significantly for those meeting the LVH criteria. Predictors (p <0.01) of HLVM were age (odds ratio 0.66), height (odds ratio 1.47), waist/hip ratio (odds ratio 1.30), systolic blood pressure (odds ratio 1.18); low-density lipoprotein cholesterol (odds ratio 0.97), log insulin (odds ratio 2.10), dietary kilocalories (odds ratio 1.16), weekly energy expenditure (odds ratio 0.53), hypertension (odds ratio 1.61), current estrogen use (odds ratio 0.60), and current smoker (odds ratio 0.47). The presence of the metabolic syndrome was related to all LVH indexes, with odds ratios of 4.95, 2.24, and 2.35, respectively, for HLVM, Cornell voltage, and Minnesota Code. In conclusion, the prevalence of LVH varied by ethnicity and the electrocardiographic index used. However, the baseline traits, especially the factors associated with the metabolic syndrome, were consistently and strongly related to all LVH indexes, particularly HLVM. Intervention on these factors may provide strategies for reducing LVH, a strong independent risk factor for cardiovascular morbidity and mortality among women.

The lord of the ring: mandatory role of the kidney in drug therapy of hypertension

Strong evidence supports the idea that total peripheral resistance (TPR) is increased in all forms of human and experimental hypertension. Although the etiological participation of TPR in the origin and long-term maintenance of hypertension has been extensively debated, it now seems clear that the renal, nonadaptive, infinite gain-working, pressure-sensitive natriuresis and diuresis is the main mechanism of blood pressure control in the long term. The tissue, cellular, biochemical, and genetic sensors and executors of this process have not been fully identified yet, but the role of the renal medulla has gained growing attention as the physiopathological scenario in which the key regulatory elements reside. Specifically, the functionality of the renomedullary vasculature seems to be highly responsible for blood pressure control. The vasculature of the renal medulla becomes a new and more specific target for the therapeutic intervention of hypertension. Recent data on the effect of baroreceptor-controlled renal sympathetic activity on the long-term regulation of blood pressure are integrated. The renomedullary effects of the main antihypertensive drugs are discussed, and new perspectives for the therapeutic intervention of hypertension are outlined. Comparison of the genetic program of the renal medulla before and after the development of hypertension in spontaneously hypertensive and experimentally induced animal models might provide a mechanism for identifying the key genes that become activated or suppressed in the development of high blood pressure. These genes, their encoded proteins, or other elements related to their signalling and genetic pathways might serve as new and more specific targets for the pharmacological treatment of abnormally elevated blood pressure. Besides, proteins specifically located to the luminal side of the renomedullary vascular endothelium may serve as potential targets for site-directed drug and gene therapy.

Putting the brakes on cardiac hypertrophy: exploiting the NO-cGMP counter-regulatory system

We know a great deal about the receptors and signaling pathways in cardiomyocytes that contribute to hypertrophic growth. Although drugs that target them have proven effective in substantially reducing left ventricular hypertrophy and associated mortality, cardiovascular disease remains the leading cause of death in the West. Another approach may rest with exploiting naturally occurring regulators of maladaptive cardiac hypertrophy that have been identified in the past few years. These endogenous negative regulators can be grouped, for the most part, into those constitutively active but whose activity is decreased by hypertrophic stimulation, and those with little or no baseline activity that are activated by hypertrophic stimulation. Spanning both groups are 4 systems that converge on cyclic guanosine 3', 5'-monophosphate (cGMP) generation, namely natriuretic peptides (ANP and BNP), kinins, nitric oxide (NO), and the angiotensin II type 2 receptor (AT2). Although holding promise as a means for restricting hypertrophy, each of these signaling molecules has certain limitations that need to be overcome. What follows is an overview of research over the past 2 years, much of it published in Hypertension, which has dealt with the antihypertrophic action of this particular group of endogenous signaling molecules. Understanding the function and regulation of the antihypertrophic NO-cGMP system offers the promise of novel therapeutic strategies for treating cardiac hypertrophy and heart failure.