Combination therapy in the extended cardiovascular continuum: a focus on perindopril and amlodipine

The progression of cardiovascular disease could be regarded as following atherosclerosis-related and age-related pathways. The starting points for these pathways are different--risk factors or aortic ageing--but they conclude in the same way: end-stage heart disease. Together these interlinked pathways form the extended cardiovascular continuum. Renin-angiotensin-aldosterone system (RAAS) inhibitors have been shown to interrupt or slow the progression of cardiovascular disease along one pathway, the cardiovascular atherosclerotic continuum. Cardiovascular protection with RAAS inhibitors varies; different RAAS inhibitors offer different levels of protection. Similarly, calcium channel blockers (CCBs) also have clearly shown protective effect of cardiovascular system, especially as it regards cerebrovascular disease risk. The AngloScandinavian Cardiac Outcomes Trial (ASCOT) showed that a combination of the angiotensin-converting enzyme (ACE) inhibitor perindopril and CCB amlodipine offered better cardiovascular protection in at-risk hypertensive patients than beta-blocker and thiazide. By attenuating the deleterious effects of cardiovascular disease at multiple stages of the extended cardiovascular continuum on top of lowering blood pressure (BP), perindopril and amlodipine could interrupt and slow the progression of cardiovascular disease. These antihypertensive agents have complementary vascular effects that enhance cardiovascular protection and reduce side-effects. Evidence from ASCOT shows that antihypertensive and vascular effects of amlodipine with and without perindopril have translated into real-life clinical benefits. A strategy using ACE inhibitors and CCBs, such as perindopril and amlodipine, to target multiple stages in both pathways of cardiovascular disease could effectively reduce cardiovascular risk and lower BP.

Which thiazide to choose as add-on therapy for hypertension?

Combined therapy is required in the majority of patients with hypertension to achieve blood pressure (BP) targets. Although different antihypertensive drugs can be combined, not all combinations are equally effective and safe. In this context, the combination of a renin angiotensin system inhibitor with a diuretic, usually a thiazide, particularly hydrochlorothiazide (HCTZ) or thiazide-like diuretics, such as chlorthalidone or indapamide, is recommended. However, not all diuretics are equal. Although HCTZ, chlorthalidone, and indapamide as add-on therapy effectively reduce BP levels, the majority of studies have obtained greater BP reductions with chlorthalidone or indapamide than with HCTZ. Moreover, there are data showing benefits with chlorthalidone or indapamide beyond BP. Thus, chlorthalidone seems to have pleiotropic effects beyond BP reduction. Moreover, compared with placebo, chlorthalidone has small effects on fasting glucose and total cholesterol, and compared with HCTZ, chlorthalidone achieves significantly lower total cholesterol and low-density lipoprotein cholesterol levels. Similarly, indapamide has demonstrated no negative impact on glucose or lipid metabolism. More importantly, although head-to-head clinical trials comparing the effects of indapamide or chlorthalidone with HCTZ are not available, indirect comparisons and post hoc analyses suggest that the use of chlorthalidone or indapamide is associated with a reduction in cardiovascular events. Despite this, the most frequent diuretic used in clinical practice as add-on therapy for hypertension is HCTZ. The purpose of this review is to update the published data on the efficacy and safety of HCTZ, chlorthalidone, and indapamide as add-on therapy in patients with hypertension.