Can angiotensin receptor antagonists prevent restenosis after stent placement?

Impact of renin-angiotensin system inhibitors after revascularization of patients with left main coronary artery disease

BACKGROUND

There is a paucity of data regarding the effect of inhibition of the renin-angiotensin system on outcomes after percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). We sought to examine long-term outcomes of patients with left main coronary disease (LMCAD) randomized to PCI with fluoropolymer-based cobalt-chromium everolimus-eluting stents or CABG according to treatment at discharge with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) in the large-scale, multicenter, randomized EXCEL trial.

METHODS

EXCEL randomized 1905 patients with LMCAD of low and intermediate anatomical complexity (visually-assessed SYNTAX score ≤32) to PCI (n = 948) versus CABG (n = 957). Patients were categorized according to whether they were treated with ACEI/ARB at discharge; their outcomes from discharge to 5 years were examined using multivariable logistic regression with an offset for follow-up time.

RESULTS

Among 1775 patients discharged alive with known ACEI/ARB treatment status, 896 (50.5%) were treated with one of these agents. Among those treated with ACEI/ARB, the 5-year rate of all-cause death was similar after PCI or CABG (10.7% versus 9.8% respectively, adjOR, 0.94; 95% CI, 0.56-1.57) in contrast to patients not treated with ACEI/ARB (15.0% versus 7.8%, respectively, adjOR, 2.20; 95% CI, 1.32-3.67) (Pinteraction = 0.02). Significant interactions between treatment arm (PCI versus CABG) and ACEI/ARB treatment status were also found for cardiovascular death (Pinteraction = 0.03), ischemia-driven revascularization (Pinteraction = 0.03), target vessel revascularization (Pinteraction = 0.007) and target vessel failure (Pinteraction = 0.0009).

CONCLUSION

In the EXCEL trial, the postdischarge rates of death and revascularization after 5 years were similar after PCI and CABG in patients with LMCAD treated with ACEI/ARB at discharge. In contrast, event rates were higher after PCI versus CABG in those not so treated.

Valsartan attenuates intimal hyperplasia in balloon-injured rat aortic arteries through modulating the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor axis

The role of the Mas receptor in the activity of valsartan against intimal hyperplasia is unclear. Herein, we investigated the role of the angiotensin-converting enzyme 2 (ACE2)-angiotensin-(1-7)-Mas receptor axis on the activity of valsartan against intimal hyperplasiain balloon-injured rat aortic arteries. Wistar rats were randomized equally into the sham control group, injured group, and injured plus valsartan (20 mg/kg/d)-treated group. Valsartan significantly attenuated the vascular smooth muscle cell proliferation and intimal and medial thickening on days 14 and 28 after injury. The angiotensin-(1-7) levels as well as ACE2 and Mas receptor mRNA/protein expression were significantly decreased in the injured rats, compared to the uninjured rats; meanwhile, the angiotensin II level as well as the ACE and AT1 receptor mRNA/protein expression were increased (all P < 0.05 or < 0.01). Additionally, the p-ERK protein expression was increased (P < 0.01). Treatment with valsartan significantly increased the angiotensin-(1-7) levels as well as ACE2 and Mas receptor mRNA/protein expression but decreased the angiotensin II level, ACE and AT1 receptor mRNA/protein expression, as well as the p-ERK protein expression, compared to the injured group (all P < 0.05 or < 0.01). These results suggest that valsartan attenuates neointimal hyperplasiain balloon-injured rat aortic arteries through activation of the ACE2-angiotensin-(1-7)-Mas axis as well as inhibition of the ACE-angiotensin II-AT1 and p-ERK pathways.

Valsartan decreases neointimal hyperplasia in balloon-injured rat aortic arteries by upregulating HO-1 and inhibiting angiotensin II type 1 receptor

AIMS

Upregulation of heme oxygenase (HO)-1 plays an important role in vascular protection. Valsartan attenuates neointimal hyperplasia in animal studies. The objective of this study was to examine the role of HO-1 and angiotensin II type 1 (AT1) receptor in the action of valsartan on neointimal hyperplasia in balloon-injured rat aortic arteries.

MAIN METHODS

Thirty-six male Wistar rats were randomly divided into the following three groups with twelve rats in each group: control group, surgery (model) group, and valsartan group. Aortic balloon injury was performed to elicit endothelial denudation with a 2F balloon catheter. On days 14 and 28 after injury, blood was harvested to measure bilirubin levels. Aortic arteries were harvested for morphometry analysis, to determine angiotensin II (Ang II) level, and to analyze mRNA or protein expression.

KEY FINDINGS

Compared with the control group, proliferation and intimal thickening of vascular smooth muscle cells (VSMCs) were obvious in the surgery group rats on days 14 and 28 after injury. Valsartan significantly reduced the proliferation and intimal thickening. Additionally, pretreatment with valsartan significantly reduced Ang II levels, AT1 receptor, and p38 mitogen-activated protein kinase (MAPK) expression. Valsartan increased HO-1 protein and mRNA expression, as well as increased serum bilirubin levels compared with the surgery group.

SIGNIFICANCE

Valsartan treatment decreased neointimal hyperplasia in balloon-injured rats. The mechanism of action might be linked to the upregulation of HO-1, downregulation of AT1 receptor and inhibition of p38MAPK signal pathway.

Effects of valsartan on stress-induced changes of serum vascular endothelial growth factor and nitric oxide in mice

This study investigated the effects of renin-angiotensin system (RAS) blockade on stress-induced changes of serum vascular endothelial growth factor (VEGF) and nitric oxide (NO) in mice. Chronic stress increased the serum NO levels significantly compared to control group (p = .0172). Valsartan, an angiotensin II receptor antagonist, alone, did not make significant difference versus control group. In chronic stress + valsartan group, serum NO levels decreased nonsignificantly compared to chronic stress group. There was a nonsignificant increase in serum VEGF levels after chronic stress. Valsartan alone or with chronic stress did not significantly affect the serum VEGF levels. In conclusion, there was no correlation between NO and VEGF changes during the stress response. In this respect, there may be other mechanisms to explain the stress-induced NO increase.