Comparison of therapeutic studies on regression of left ventricular hypertrophy

In numerous studies left ventricular hypertrophy has been clearly established to be a strong, blood-pressure independent risk factor for cardiovascular morbidity and mortality. In fact, increased echocardiographic left ventricular mass has been shown to predict cardiovascular complications not only in patients with hypertension, but also in the general population. Preliminary data revealed that regression of left ventricular hypertrophy indeed reduces cardiovascular complications. As a consequence, regression of left ventricular hypertrophy by drug treatment has emerged as a desirable goal in patients with echocardiographically determined left ventricular hypertrophy. These findings raised the question, whether certain antihypertensive drugs differ in their ability to reduce left ventricular mass. To resolve this issue several comparative studies and some meta- analyses have been carried out. In a meta-analysis by Dahlof et al., comprising 109 treatment studies published until december 1990 with a total of 2357 patients, ACE-inhibitors (-15%) were most effective in reducing left ventricular mass followed by diuretics (-11.3%), calcium channel blockers (- 8.5%) and β-blockers (-8%). Reduction in left ventricular mass was mainly due to a decrease in wall thickness except for diuretics which predominantly reduced ventricular diameter. Although reduction in blood pressure was similar for all antihypertensive agents, the correlation between changes in mean arterial pressure and effect on left ventricular mass was only significant for β-blockers with a modest correlation for ACE-inhibitors and no clearcut relation for diuretics and calcium channel blockers. Another meta-analysis by Cruickshank et al., screening articles for the same publication period and comprising 104 studies with a total of 2107 patients also showed best results in reducing left ventricular mass for ACE-inhibitors as single antihypertensive therapy. Calcium channel blockers were more effective than β-blockers with diuretics in the intermediate range. In a meta-analysis of Schmieder et al., only double-blind, randomized, controlled clinical studies with parallel group design were considered. Out of a large sample size of 471 studies identified by extensive literature search, only 39 studies of presumably high scientific quality, published until July 1995 fulfilled inclusion criteria. After adjustment for different durations of treatment, left ventricular mass decreased with ACE-inhibitors by 13% (95% CI: 9.9-16.8%), with calcium channel blockers by 9% (95% CI: 5.5-13.1%), with β-blockers by 6% (95% CI: 2.3-8.6%) and with diuretics by 7% (95% CI: 3.0- 10.7%) at similar fallen blood pressure. An update of this meta-analysis including all available data until the end of 1996, comprising a total of 1715 patients found a reduction of left ventricular mass by 12% (95% CI: 9.0- 14.5%) for ACE-inhibitors, by 11% (95% CI: 7.8-13.7%) for calcium channel blockers, by 5% (95% CI: 1.2-7.3%) for β-blockers and by 8% (95% CI: 3.9- 11.1%) for diuretics. Regarding the available data, blockade of angiotensin II by ACE-inhibitors emerged as the most potent approach for the treatment of left ventricular hypertrophy. The most recent updated meta-analysis revealed that calcium channel blockers emerged to be similarly potent or according to other studies to be at least the second choice of drug class.