Effects of inhibitors of angiotensin-converting enzyme on regional hemodynamics

Patients with Prior Exposure to a Combination of Statins & Angiotensin-Converting Enzyme Inhibitors (ACE-Is)/Angiotensin Receptor Blockers (ARBs) Have Better Outcomes after Carotid Revascularization than Patients with Prior Exposure to Statins Alone: A MultiCenter Analysis

BACKGROUND

Statin use has been studied and confirmed to have a beneficial impact on perioperative carotid endarterectomy (CEA) and carotid artery stenting (CAS) outcomes. The benefits of Angiotensin-converting enzyme inhibitors (ACE-I) in hypertension, ischemic heart disease, heart failure, diabetes mellitus, and renal disease are well-known; however, the impact of continuing or withholding ACE-Is/angiotensin receptor blockers (ARBs) on CEA and CAS outcomes is not addressed well in the literature. This study aimed to evaluate the impact of preoperative statin use combined with ACE-Is/ARBs in patients undergoing CEA or CAS on mortality and morbidity using a multi-institutional database.

METHODS

Using the data of all patients who underwent carotid artery revascularization, including CEA, transcarotid artery revascularization, and transfemoral carotid artery stenting from 2016 to 2021 in the Vascular Quality Initiative data, we determined as our primary outcome 30-day mortality/stroke after carotid revascularization based on periop exposure to statins alone, or the combination of statins and ACE-Is/ARBs. Secondary outcomes were postop myocardial infarction and postop congestive heart failure. Poisson regression with robust variance was used to determine postop outcomes comparing the combination of statin and ACE-Is/ARBs group with statins alone group.

RESULTS

A total of 131,285 patients were included in the study, with 59,860 (46%) patients receiving statin only, and 71,425 (54%) receiving both statin and ACE-Is/ARBs preoperatively. Both patient groups differed significantly in preop clinical and demographic characteristics. After adjusting for potential confounders, the statins plus ACE-I/ARB group had a 12% lower risk of postop mortality/stroke (Incident Rate Ratio comparing Statin/ACE group to Statins Only group [IRR] 0.88, 95% confidence interval 0.81-0.95, P = 0.001), 18% lower risk of postop congestive heart failure (IRR 0.82, 95% CI 0.68-0.98, P = 0.029), and similar risk of postop myocardial infarction (IRR 1.05 95% confidence interval 0.91-1.20, P = 0.54) compared to the statin-only group.

CONCLUSION

Statins combined with ACE-Is/ARBs perioperatively offer better protection compared to statins alone in patients undergoing carotid revascularization surgery. We recommend the continuation of ACE-Is/ARBs use in patients undergoing carotid revascularization, especially if they have concurrent hypertension. Further prospective studies are needed to evaluate the benefit of adding ACE-Is/ARBs.

Role of Renin-Angiotensin-Aldosterone System Inhibition in Patients Undergoing Carotid Revascularization

Background

Previous data suggest that using renin‐angiotensin‐aldosterone system inhibitors (RAASIs) improves survival in patients with cardiovascular diseases. We sought to investigate the association of different patterns of use of RAASIs on perioperative and 1‐year outcomes following carotid revascularization.

Methods and Results

We investigated patients undergoing carotid revascularization, either with carotid endarterectomy or transfemoral carotid artery stenting, in the VQI (Vascular Quality Initiative) VISION (Vascular Implant Surveillance and Interventional Outcomes Network) data set between 2003 and 2018. We divided our cohort into 3 groups: (1) no history of RAASI intake, (2) preoperative intake only, and (3) continuous pre‐ and postoperative intake. The final cohort included 73 174 patients; 44.4% had no intake, 50% had continuous intake, and 5.6% had only preoperative intake. Compared with continuous intake, preoperative and no intake were associated with higher odds of postoperative stroke (odds ratio [OR], 1.7 [95% CI, 1.5–1.9]; P<0.001; OR, 1.1 [95% CI, 1.03–1.2]; P=0.010); death (OR, 4.8 [95% CI, 3.8–6.1]; P<0.001; OR, 1.9 [95% CI, 1.6–2.2]; P<0.001); and stroke/death (OR, 2.05 [95% CI, 1.8–2.3]; P<0.001; OR, 1.2 [95% CI, 1.1–1.3]; P<0.001), respectively. At 1 year, preoperative and no intake were associated with higher odds of stroke (hazard ratio [HR], 1.4 [95% CI, 1.3–1.6]; P<0.001; HR, 1.15, [95% CI, 1.08–1.2]; P<0.001); death (HR, 1.7 [95% CI, 1.5–1.9]; P<0.001; HR, 1.3 [95% CI, 1.2–1.4]; P<0.001); and stroke/death (HR, 1.5 [95% CI, 1.4–1.7]; P<0.001; HR, 1.2 [95% CI, 1.17–1.3]; P<0.001), respectively.

Conclusions

Compared with subjects discontinuing or never starting RAASIs, use of RAASIs before and after carotid revascularization was associated with a short‐term stroke and mortality benefit. Future clinical trials examining prescribing patterns of RAASIs should aim to clarify the timing and potential to maximize the protective effects of RAASIs in high‐risk vascular patients.

Effect of preoperative angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker use on hemodynamic variables in pediatric patients undergoing cardiopulmonary bypass

BACKGROUND

Some have suggested that children undergoing cardiac surgery who receive angiotensin-converting enzyme (ACE) inhibitors experience a greater degree of hypotension after anesthesia induction and in the immediate postcardiopulmonary bypass period than children who did not receive these drugs. Therefore, we examined the effect of ACE inhibitor/angiotensin II receptor blocker (ARB) therapy on intraoperative hemodynamics and vasopressor use in pediatric patients undergoing cardiac surgery.

METHODS

In a retrospective cohort study of patients younger than 18 years who underwent cardiopulmonary bypass between March 1, 2010, and April 1, 2011, we compared intraoperative hemodynamics and vasopressor use between patients who received preoperative ACE inhibitor/ARB therapy and those who did not. The primary outcome was vasoactive infusion score after cardiopulmonary bypass.

RESULTS

The occurrence of hypotension did not differ significantly between the ACE inhibitor/ARB group and the control group during induction of anesthesia or at any time point after cardiopulmonary bypass. At 0, 30, 60, and 90 minutes after cessation of cardiopulmonary bypass, patients on ACE inhibitor/ARB therapy tended to have a higher vasoactive infusion score (7.1, 7.6, 9.4, and 11.3) than patients in the control group (6.3, 6.1, 6.0, and 6.7). Although this difference became more pronounced over time, it did not reach statistical significance.

CONCLUSION

The use of preoperative ACE inhibitors and ARBs in pediatric patients undergoing cardiac surgery did not significantly increase the incidence of hypotension after induction of anesthesia and did not increase significantly the vasoconstrictor requirements upon weaning from cardiopulmonary bypass; however, additional prospective studies are needed.

Effects of long-acting angiotensin-converting enzyme inhibitor, imidapril, on the lower limit of cerebral blood flow autoregulation in hypertensive rats

The objective of the present study was to examine the effects of a long-acting angiotensin converting enzyme inhibitor, imidapril ((4S)-1-methyl-3-¿(2S)-2-[N-(1S)-1-ethoxycarbonyl-3-phenylpropyl) amino] propionyl¿-2-oxoimidazolidine-4-carboxylic acid hydrochloride), for 7 days on the cerebral blood flow autoregulatory response to hypotension in hypertensive rats. We measured the cerebral blood flow at rest and during hemorrhagic hypotension, using laser-Doppler flowmetry. At the same time, the absolute baseline cerebral blood flow values in the parietal cortex were quantified with the hydrogen clearance method. After administration of imidapril at a dose of 5 mg/kg/day for 7 days, the resting value of mean arterial blood pressure was significantly decreased by 25 mm Hg (P < 0.001), cerebral vascular resistance was lowered by 14.4% (P < 0.05) and the lower limit of cerebral blood flow autoregulation was shifted to a lower level, 106+/-11 mm Hg (mean +/- S.D.), from 137+/-8 mm Hg in the control group (P < 0.001), while resting cerebral blood flow remained unchanged. The present results demonstrated that imidapril preserves cerebral blood flow and significantly shifts the lower limit of cerebral autoregulation towards lower blood pressure levels.

Inhibition of angiotensin-converting enzyme modulates the autoregulation of regional cerebral blood flow in hypertensive rats

The inhibition of angiotensin-converting enzyme activities is considered to favorably modulate the hemodynamics of the brain. We designed the present study to examine the effects of angiotensin-converting enzyme inhibitors on regional differences in the lower limits of cerebral blood flow autoregulation in spontaneously hypertensive rats. Angiotensin-converting enzyme inhibitors (either 10 mg/kg captopril or SQ 29,852 in saline) were intravenously injected 15 minutes before hemorrhagic hypotension was induced. Cerebral blood flows to the parietal cortex and thalamus were simultaneously measured by hydrogen clearance. Both captopril and SQ 29,852 significantly decreased mean arterial pressure by 14 to 18 mm Hg and also reduced calculated cerebral vascular resistance by 11% to 15% of resting values, which resulted in a well-maintained cerebral blood flow. The lower limits of autoregulation were 76 +/- 2% (mean +/- SEM) and 77 +/- 2% of resting values in the cortex and thalamus, respectively, in control rats. Administration of either captopril or SQ 29,852 significantly reduced the lower limits to 65 +/- 3% (P < .01 versus control) and 67 +/- 2% (P < .05), respectively, in the cortex, which were slightly but always larger than the 71 +/- 3% and 71 +/- 2% reduction, respectively, in the thalamus. The inhibition of angiotensin-converting enzyme activities thus may be more protective against acute hypotension for cerebral microcirculation in the cortex than in the thalamus.

Angiotensin converting enzyme inhibitors attenuate ischemic brain metabolism in hypertensive rats

BACKGROUND AND PURPOSE

Angiotensin converting enzyme (ACE) inhibitors are expected to modulate neuronal activities. The present study was designed to examine the beneficial effects of ACE inhibitors on microcirculation and metabolism in the ischemic brain.

METHODS

Cerebral ischemia was developed for 60 minutes in spontaneously hypertensive rats (SHR, n = 35) by bilateral carotid artery occlusion. ACE inhibitor (0.1 or 10 mg/kg SQ 29,852 or captopril) were intravenously injected 15 minutes before cerebral ischemia. Cerebral blood flow to the parietal cortex was measured with the H2 clearance technique. Lactate, pyruvate, and ATP in the brain were estimated by the enzymatic method.

RESULTS

Before cerebral ischemia, high doses of both SQ 29,852 and captopril significantly decreased mean arterial pressure by 15 to 25 mm Hg and reduced cerebral vascular resistance by 13% to 17% of the resting values. Cerebral blood flow and arterial pressure during ischemia were not altered by these ACE inhibitors. After 60 minutes of cerebral ischemia, tissue lactate in vehicle-treated SHR increased 6.6-fold and ATP decreased to 65% of the control values. Administration of SQ 29,852 or captopril significantly reduced the lactate levels to 1.6- to 3.1-fold and well preserved the ATP levels to 82% to 93% of the control.

CONCLUSIONS

These results suggest that inhibition of ACE activities may be protective for cerebral metabolism against ischemic insult.

The effect of captopril on the superior mesenteric artery and portal venous blood flow in normal man

1. Measurements of superior mesenteric artery and portal venous blood flow were made non-invasively along with systemic and other regional (cardiac index, forearm and cutaneous blood flow) vascular responses to acute ingestion of the ACE inhibitor captopril (50 mg) or placebo (50 mg vitamin C), in 12 healthy subjects while supine and during head-up tilt. 2. After captopril, superior mesenteric artery and portal blood flow rose markedly with a reduction in superior mesenteric artery vascular resistance. Supine blood pressure was unchanged but cardiac index and forearm blood flow rose; during head-up tilt, blood pressure fell in some subjects. 3. There was a rise in levels of plasma renin activity and a fall in levels of plasma angiotensin II after captopril. After placebo, there were no significant changes in splanchnic blood flow, systemic or other regional responses and in biochemical measurements, while supine. 4. Our studies indicate that captopril is a potent dilator of the splanchnic vascular bed and suggest that this action may contribute to its therapeutic effects. The studies indicate a role for angiotensin II in the control of this large vascular bed although other agents (bradykinin, prostacyclin) may contribute.