Left ventricular hypertrophy: a new approach for fibrosis inhibition

Anti-hypertensive drugs have different effects on ventricular hypertrophy regression

OBJECTIVES

There is a direct relationship between the regression of left ventricular hypertrophy (LVH) and a decreased risk of mortality. This investigation aimed to describe the effects of anti-hypertensive drugs on cardiac hypertrophy through a meta-analysis of the literature.

METHODS

The Medline (via PubMed), Lilacs and Scielo databases were searched using the subject keywords cardiac hypertrophy, antihypertensive and mortality. We aimed to analyze the effect of anti-hypertensive drugs on ventricle hypertrophy.

RESULTS

The main drugs we described were enalapril, verapamil, nifedipine, indapamina, losartan, angiotensin-converting enzyme inhibitors and atenolol. These drugs are usually used in follow up programs, however, the studies we investigated used different protocols. Enalapril (angiotensin-converting enzyme inhibitor) and verapamil (Ca(++) channel blocker) caused hypertrophy to regress in LVH rats. The effects of enalapril and nifedipine (Ca(++) channel blocker) were similar. Indapamina (diuretic) had a stronger effect than enalapril, and losartan (angiotensin II receptor type 1 (AT1) receptor antagonist) produced better results than atenolol (selective beta1 receptor antagonist) with respect to LVH regression.

CONCLUSION

The anti-hypertensive drugs induced various degrees of hypertrophic regression.

Relation Between Flow Reserve Capacity of Penetrating Intramyocardial Coronary Arteries and Myocardial Fibrosis in Hypertension: Study Using Transthoracic Doppler Echocardiography

OBJECTIVE

The purpose of this study was to compare coronary flow reserve (CFR) capacity of penetrating intramyocardial coronary artery (PICA) using transthoracic Doppler echocardiography and biochemical marker of myocardial fibrosis in hypertension (HTN).

METHODS

In 58 patients (male:female ratio = 31:27; mean age 47 +/- 9 years) with chest pain and normal coronary angiogram findings, the width of color Doppler signal and peak diastolic velocity of PICA flow were measured in the myocardium just beneath the apical impulse window using transthoracic Doppler echocardiography. PICA-CFR and PICA-width ratio were calculated as the ratio of hyperemic to baseline peak diastolic velocity and as the ratio of hyperemic to baseline width after the adenosine infusion (140 mug/kg/min), respectively. Serum carboxy-terminal propeptide of procollagen type I, as a biochemical marker, was measured and patients were divided into 3 groups: 19 with HTN and PICA-CFR less than 2.0 (group A); 23 with HTN and PICA-CFR of 2.0 or more (group B); and 16 who were normotensive with PICA-CFR of 2.0 or more (group C).

RESULTS

Baseline peak diastolic velocity for group A was higher than the other two groups (P < .005 vs groups B and C). PICA-width ratio was higher than the other two groups (P < .005 vs groups B and C). Serum propeptide of type I was 137.1 +/- 16.6 ng/mL in group A, 96.2 +/- 13.7 ng/mL in group B, and 78.8 +/- 11.2 ng/mL in group C (P < .0001 vs group B and group C). PICA-CFR was closely related to serum propeptide of type I (P < .001, r = -0.723).

CONCLUSION

The impaired PICA-CFR is related to myocardial fibrosis in patients with HTN, chest pain, and normal coronary angiogram results.

Left ventricular filling abnormalities and obesity-associated hypertension: relationship with overproduction of circulating transforming growth factor β1

This study has been designed to evaluate the relationship among transforming growth factor beta1 (TGFbeta1) and some measurements of diastolic function in a population of hypertensive subjects with normal left ventricular ejection fraction. We studied 67 hypertensive outpatients who according to their BMI levels were subdivided into three groups: lean (L), overweight (OW) and obese (OB) hypertensives (HT). Circulating TGFbeta1 and M- and B-mode echocardiography was determined. All hypertensives were further subgrouped, according to European Society of Cardiology Guidelines, into two subsets of patients with normal diastolic function or with diastolic dysfunction. Prevalence of left ventricular hypertrophy (LVH) was determined in all the groups. TGFbeta1, left ventricular mass (LVM), LVM/h(2.7), E-wave deceleration time and isovolumic relaxation time (IVRT) were significantly (P < 0.005) higher and E/A velocity ratio was significantly (P < 0.05) lower in OW-HT and OB-HT than in L-HT. Prevalence of LVH was significantly higher (P < 0.03) in group OB-HT than in L-HT. TGFbeta1 (P < 0.004), LVM/h(2.7) (P < 0.001) and prevalence of LVH were (P < 0.01) significantly higher in hypertensives with diastolic dysfunction than hypertensives with normal diastolic function. TGFbeta1 levels were positively correlated with BMI (r = 0.60; P < 0.0001), LVM/h(2.7) (r = 0.28; P < 0.03), IVRT (r = 0.30; P < 0.02) and negatively with E/A ratio (r = -0.38; P < 0.002) in all HT. Multiple regression analysis indicated that TGFbeta1, BMI and IVRT were independently related to E/A ratio explaining 71% of its variability (r = 0.84; P < 0.0001). This relationship was independent of LVH, age and HR suggesting that TGFbeta1 overproduction may be considered a pathophysiological mechanism in the development of left ventricular filling abnormalities in obesity-associated hypertension.

Regression of left ventricular hypertrophy is a key goal of hypertension management

Left ventricular hypertrophy (LVH) in patients with hypertension is associated with an increased risk for many cardiovascular events and predicts a higher mortality rate. The pathogenesis of LVH is complicated. In addition to the hemodynamic burden (pressure or volume overload) and demographic factors, several trophic humoral factors, such as angiotensin II, aldosterone, endothelin, leptin, and catecholamines, may also contribute to the development and progression of LVH. Effective antihypertensive therapy can reverse LVH as well as prevent its development. Regression of LVH decreases subsequent cardiovascular morbidity and mortality. The commonly used drugs have various effects on LVH. Angiotensin receptor blockers and angiotensin-converting enzyme inhibitors seem most effective. Several new agents, including direct antifibrotic drugs, aldosterone blockade, vasopeptidase inhibitors, and endothelin receptor antagonists that more specifically target the underlying pathogenesis of LVH may provide us with innovative approaches to treat LVH.