Angiotensin converting enzyme inhibitor–calcium antagonist combination: an alliance for cardioprotection?

Optimizing the treatment of hypertension and stable coronary artery disease: clinical evidence for fixed-combination perindopril/amlodipine

BACKGROUND

Optimized management of hypertension and coronary artery disease (CAD) improves cardiovascular risk and outcomes, and prevents complications. This article reviews evidence for the fixed combination of the angiotensin-converting enzyme (ACE) inhibitor perindopril and the calcium channel blocker amlodipine.

METHODS

A literature search was performed in PubMed/MEDLINE to identify articles published in English between 1988 and March 2008 describing clinical trials, particularly outcome trials, or mechanisms of therapeutic action relevant to the use of combination therapy in patients with hypertension or stable coronary artery disease with an ACE inhibitor (perindopril) and a calcium channel blocker (amlodipine).

FINDINGS

Clinical trials indicate that this combination may have a positive impact on cardiovascular mortality and morbidity in hypertensive individuals. The two complementary mechanisms of action appear to work in synergy, leading to more efficient blood pressure lowering, improved fibrinolytic function, and reduction of secondary effects. This also represents a simplified management strategy for stable CAD. Perindopril has proven efficacy in the prevention of cardiovascular events and mortality in CAD patients, while amlodipine is widely used in the symptomatic management of CAD. Both aspects of guideline-recommended management of CAD are therefore addressed in a single tablet.

CONCLUSIONS

The clinical evidence for fixed-combination perindopril/amlodipine indicates it as a credible option for the optimization of the management of hypertension and CAD.

Beneficial effects of combined benazepril-amlodipine on cardiac nitric oxide, cGMP, and TNF-alpha production after cardiac ischemia

The aim of this study was to determine if myocardial inflammation is increased after myocardial ischemia and whether angiotensin-converting enzyme inhibitors, calcium channel blockers, or diuretics decrease mediators of inflammation in rats with induced myocardial ischemia. Changes in cardiac interstitial fluid (CIF) levels of nitric oxide metabolites (NOX), cyclic guanosine 3',5'-monophosphate (cGMP), angiotensin II (Ang II), and tumor necrosis factor-alpha (TNF-alpha) were monitored with/without oral administration of benazepril, amlodipine, combined benazepril-amlodipine, or hydrochlorothiazide. Using a microdialysis technique, levels of several mediators of inflammation were measured after sham operation or 30-minute occlusion of the left anterior descending coronary artery. Compared with sham animals, levels of CIF NOX and cGMP were decreased in animals with ischemia (P < 0.001). Benazepril or amlodipine significantly increased NOX levels (P < 0.05 vs. untreated ischemia), but only benazepril significantly increased cGMP (P < 0.05). Combined benazepril-amlodipine further increased CIF NOX and cGMP (P < 0.001), compared with either drug alone. CIF Ang II and TNF-alpha in sham animals did not change significantly. In animals with ischemia, CIF Ang II and TNF-alpha increased progressively. Amlodipine alone, benazepril alone, or combined benazepril-amlodipine significantly reduced TNF-alpha (P < 0.01 for monotherapies and P < 0.001 for combination therapy). Hydrochlorothiazide did not cause significant changes in NOX, cGMP, or TNF-alpha. Combination benazepril-amlodipine may be beneficial for managing cardiac ischemia.

The first hypertension trial comparing the effects of two fixed-dose combination therapy regimens on cardiovascular events: Avoiding Cardiovascular events through Combination therapy in Patients Living with Systolic Hypertension (ACCOMPLISH)

Current recommendations for the treatment of hypertension clarify the need to achieve lower blood pressure levels in the general population (<140/90 mm Hg) and in specific high-risk patient groups such as patients with diabetes or chronic renal disease (<130/80 mm Hg). Further, it is evident that to reach appropriate blood pressure control, most patients with high blood pressure will require two or more antihypertensive agents. There is scarce clinical trial outcome evidence to guide clinicians in the selection of optimal combinations of antihypertensive classes for high-risk hypertensive patients. A new clinical trial, Avoiding Cardiovascular Events through Combination Therapy in Patients Living with Systolic Hypertension (ACCOMPLISH), is the first large clinical trial to directly compare cardiovascular mortality and morbidity rates for two fixed-dose combination therapies. Results from ACCOMPLISH should provide much-needed guidance for selecting optimal combination therapy for high-risk hypertensive patients.

Amlodipine enhances NO production induced by an ACE inhibitor through a kinin-mediated mechanism in canine coronary microvessels

Our previous study found that angiotensin-converting enzyme (ACE) inhibitors and amlodipine induce NO release from coronary microvessels through a kinin-dependent mechanism. The goal of this study was to determine whether amlodipine could potentiate NO formation during ACE inhibition. Coronary microvessels were isolated from 16 mongrel dogs. Nitrite, the hydration product of NO, from coronary microvessels was quantified by using the Griess reaction. Bradykinin and kallikrein all significantly increased nitrite release from coronary microvessels in a concentration-dependent manner. The ACE inhibitor, ramiprilat, potentiated these effects. Amlodipine also markedly potentiated nitrite production by ramiprilat. For instance, amlodipine (10(-10) M) enhanced nitrite release induced by ramiprilat (10(-7) M) from 122 +/- 9 to 168 +/- 14 pmol/mg (p < 0.05 vs. ramiprilat). Nitrite release potentiated by ramiprilat and amlodipine was entirely blocked by N(omega)-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NO synthase), HOE 140 (Icatibant, a specific B2-kinin receptor antagonist), and dichloroisocoumarin (DCIC, a serine protease inhibitor that blocks local kinin formation). These results clearly show that there is a synergistic effect on NO formation when amlodipine is combined with ACE inhibition. Our data suggest that kinin-mediated coronary NO production may contribute importantly to the beneficial therapeutic action of ACE inhibitors, especially in combination with amlodipine in the treatment of heart disease.

Combination of a calcium antagonist, a lipid-peroxidation inhibitor, and an angiotensin AT1-receptor antagonist provides additive myocardial infarct size-limiting effect in pigs

The calcium antagonist felodipine, the lipid-peroxidation inhibitor H290/51, and the angiotensin II type 1 (AT1)-receptor antagonist candesartan all exert beneficial effects on myocardial ischemia/reperfusion injury. This study was undertaken to test the hypothesis that a combination of these drugs with different pharmacologic properties could exert additive cardioprotective effects. Anesthetized pigs were subjected to 45 min of left anterior descending coronary artery occlusion followed by 240 min of reperfusion. Five groups of pigs were randomly given either 0.65 microM (7 nmol/kg) felodipine, 1.0 microM (3.1 microg/kg) H 290/51, 4.2 microM (20 microg/kg) candesartan, a cocktail of these three drugs, or vehicle (n = 6 for each) for 30 min starting at 5 min before reperfusion by coronary venous retroinfusion, which delivers drugs specifically to the ischemic regions. Systolic segment shortening (%SS) was measured by sonomicrometer. The myocardial area at risk and the final infarct size were determined by Evans blue and 2,3,5-triphenyl tetrazolium chloride staining. The hemodynamics did not change significantly during the study. In the vehicle group, the recovery of coronary flow was not maintained during reperfusion, and it was significantly lower after 240 min of reperfusion than during the preischemic period (p < 0.05). The coronary flow in the drug-treated groups was approximately the same by the end of the reperfusion period as that before the induction of ischemia. In the ischemic myocardium, %SS slightly recovered during reperfusion in the four drug-treated groups, but not in the vehicle group. The infarct size, expressed as a percentage of the myocardial area at risk, was smaller in all four drug-treated groups compared with the vehicle group. The infarct size in the cocktail group was significantly smaller than that in the groups given felodipine, H290/51, or candesartan alone. These results demonstrate that a combination of a calcium antagonist, a lipid-peroxidation inhibitor, and an angiotensin AT1-receptor antagonist has an additive effect on infarct limitation, indicating that combined therapy with agents having different pharmacologic modes of action may provide better cardioprotection than any of the drugs alone. The findings also support the view that reperfusion injury is possibly mediated by a combination of mechanisms.