Hypertension and left ventricular hypertrophy: is drug therapy beneficial?

Association of white blood cell counts with left ventricular mass index in hypertensive patients undergoing anti-hypertensive drug therapy

Although studies using animal models have demonstrated that nonhemodynamic factors, including inflammatory cells and cytokines, contribute to left ventricular hypertrophy (LVH), there is little clinical data to confirm this association. Therefore in the present study, levels of circulating specific types of leukocyte were measured to determine the association between white blood cells and left ventricular mass index (LVMI) in hypertensive patients undergoing anti-hypertensive drug therapy. A total of 144 consecutive hypertensive patients taking anti-hypertensive drug therapy were enrolled in the current study. Subjects were divided into two groups: Those with normal geometry and those with left LVH. Total white blood cells and differentiated subtypes (neutrophils, lymphocytes, monocytes) were counted, and left ventricular end-diastolic diameter, left ventricular posterior wall thickness in diastole and inter-ventricular septal wall thickness in diastole were all measured. Analysis revealed a significant correlation between LVMI and total white blood cell levels (P=0.013). The percentage of LVH in the highest tertile of WBC was increased compared with the middle tertile (P=0.008). Furthermore, a significant correlation between the highest tertile of neutrophil counts and LVH was observed (P=0.039). However, no significant associations between LVMI and monocyte or lymphocyte counts were detected. Therefore, the current study determined that increased total white blood cell and neutrophil subtype counts were associated with LVMI in hypertensive patients undergoing anti-hypertensive drug therapy. They may provide convenient and useful markers for further risk appraisal of LVH caused by nonhemodynamic factors of hypertension.

Current perspective on the use of angiotensin-converting enzyme inhibitors in the management of coronary (atherosclerotic) artery disease

OBJECTIVE

To review the pathophysiology of atherosclerosis, the role of the renin-angiotensin system in atherogenesis, and studies supporting the potential beneficial effects of angiotensin-converting enzyme (ACE) inhibitors in reducing cardiovascular events with long-term use.

BACKGROUND

Through its action in converting angiotensin I to angiotensin II and by degrading bradykinin, local tissue ACE exerts many effects that can contribute to the development of atherosclerosis. Therefore, the use of ACE inhibitors can possibly result in antiatherogenic effects. Possible mechanisms for antiatherogenic effects of ACE inhibitors include: (1) reduction of blood pressure; (2) antiproliferative and antimigratory effects on vascular smooth muscle cells, neutrophils, and monocytes; (3) restoration of endothelial function; (4) stabilization of fatty plaque by preventing vasoconstriction; (5) antiplatelet effects; and (6) enhancement of endogenous fibrinolysis.

DATA SOURCES

English-language clinical studies, abstracts, and review articles pertaining to the use of ACE inhibitors and atherosclerosis.

STUDY SELECTION AND DATA EXTRACTION

Relevant human studies examining the role of ACE inhibitors and atherosclerosis.

DATA SYNTHESIS

Studies evaluating the possible beneficial effects of ACE inhibitors in the development of atherosclerosis are reviewed and critiqued. Design of ongoing studies with clinical and surrogate end points are discussed.

CONCLUSIONS

Based on current published studies, recommendations are made regarding the use of ACE inhibitors in atherosclerosis. Therapeutic monitoring parameters for efficacy and adverse effects are also reviewed.

Physical performance is preserved after regression of left ventricular hypertrophy

Reversal of left ventricular hypertrophy has been shown to improve left ventricular diastolic function in elderly patients with hypertension, but little is known about whether this affects physical performance. Left ventricular mass, cardiac function at rest and during submaximal exercise, and physical performance were assessed in 38 elderly patients with hypertension with left ventricular hypertrophy and normal systolic function before and after 8 and 14 months of therapy with amlodipine or hydrochlorothiazide or both. Blood pressure control was achieved with amlodipine in 18 patients, with hydrochlorothiazide in seven, and with the combination of these drugs in 13. Left ventricular mass index was similarly reduced from approximately 150 to approximately 100 g/m2 at 14 months' in each treatment group. Systolic function was maintained with the three treatment regimens, whereas similar decreases in time to peak filling rate and increases in first-third filling fraction occurred both at rest and during submaximal exercise after 8 months and further after 14 months of therapy. Exercise capacity did not significantly change in the group as a whole, but individual changes in peak oxygen uptake at the end of treatment correlated significantly with the decrease in time to peak filling rate during submaximal exercise (r = -0.49; p < 0.01). It is concluded that long-term blood pressure control with amlodipine or hydrochlorothiazide or both is associated with significant reductions in left ventricular mass and improved diastolic function in elderly patients with hypertension with left ventricular hypertrophy. Despite this reduction in left ventricular mass, left ventricular systolic function and physical performance are well preserved during submaximal exercise.

Calcium channel blockers and hypertension: evolving perspective--1996

In recent years, calcium channel blockers (CCBs) have been used extensively in the United States and elsewhere as antihypertensive agents, and their availability has been an important advance in the management of hypertension. As antihypertensive agents, the CCBs thus appear considerably more versatile than most previous vasodilators. The available studies indicate that CCBs are metabolically neutral and do not exacerbate dyslipidemia or impair glucose tolerance. In contrast to diuretics and beta-blockers, CCBs do not appear to alter insulin sensitivity. The CCBs also differ from previous vasodilators because of their favorable accompanying effects on the heart and kidney. Despite the attributes of CCBs enumerated earlier, a number of recent retrospective analyses by Psaty et al. (JAMA 1995;274:620-625) have suggested that CCBs may be detrimental and may promote adverse cardiovascular events. I have recently reviewed the results of Psaty's meta-analysis and report (Arch Intern Med 1995;155: 2150-2156). I have emphasized that it is the rate of drug delivery into the systemic circulation that produces profound effects on the hemodynamic and neurohumoral responses to a dihydropyridine CCB drug. During chronic treatment with dihydropyridines, major fluctuations in blood pressure (rapid onset and offset of antihypertensive effects) during the dosing interval may persist for drugs and formulations that are short acting. In contrast, slow-release formulations of otherwise rapidly absorbed dihydropyridines achieve a more gradual and sustained antihypertensive effect. It is probable that newer CCB formulations that do not provoke intermittent sympathetic activation and do not evoke a cardioacceleratory response would not be expected to promote adverse cardiovascular events.

Physiologic effects of long-term hypertension control

Various antihypertensive agents may reduce blood pressure to a similar degree, yet they produce different outcomes with respect to long-term end-organ damage. Effective antihypertensive therapy can prevent or even reverse established left ventricular hypertrophy. The most rapid and extensive regression occurs with agents that block the reninangiotensin system or reduce entry of calcium into the cells. Other classes of drugs that reliably reverse left ventricular hypertrophy are centrally acting adrenergic inhibitors and beta blockers. The effect of antihypertensive agents on atherosclerosis appears to differ widely with regard to lipid metabolism, insulin sensitivity, and the biology of endothelium and vascular smooth muscle. Hypertension and chronic renal failure (diabetic and nondiabetic) are closely allied, but available antihypertensive agents are not equally potent in reducing intraglomerular pressure.