Effects of captopril on myocardial protection during cardioplegia

The immunomodulatory effects of antihypertensive therapy: A review

Hypertension remains the leading preventable risk factor for stroke and coronary artery disease, significantly contributing to all-cause global mortality and predisposing patients to renal and heart failure, as well as peripheral vascular disease. Due to the widespread usage of antihypertensive drugs, global mean blood pressure has remained unchanged or even slightly decreased over the past four decades. However, considering the broad spectrum of mechanisms involved in the action of antihypertensive drugs and the prevalence of their target receptors on immune cells, possible immunomodulatory effects which may exert beneficial effects of lowering blood pressure but also potentially alter immune function should be considered. In this review, we attempt to assess the consequences to immune system function of administering the five most commonly prescribed groups of antihypertensive drugs and to explain the mechanisms behind those interactions. Finally, we show potential gaps in our understanding of the effects of antihypertensive drugs on patient health. With regard to the widespread use of these drugs in the adult population worldwide, the discussed results may be of vital importance to evidence-based decision-making in daily clinical practice.

Perioperative angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers for preventing mortality and morbidity in adults

BACKGROUND

Perioperative hypertension requires careful management. Angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) have shown efficacy in treating hypertension associated with surgery. However, there is lack of consensus about whether they can prevent mortality and morbidity.

OBJECTIVES

To systematically assess the benefits and harms of administration of ACEIs or ARBs perioperatively for the prevention of mortality and morbidity in adults (aged 18 years and above) undergoing any type of surgery under general anaesthesia.

SEARCH METHODS

We searched the current issue of the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 12), Ovid MEDLINE (1966 to 8 December 2014), EMBASE (1980 to 8 December 2014), and references of the retrieved randomized trials, meta-analyses, and systematic reviews.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing perioperative administration of ACEIs or ARBs with placebo in adults (aged 18 years and above) undergoing any type of surgery under general anaesthesia. We excluded studies in which participants underwent procedures that required local anaesthesia only, or participants who had already been on ACEIs or ARBs.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, assessed the risk of bias, and extracted data. We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included seven RCTs with a total of 571 participants in the review. Two of the seven trials involved 36 participants undergoing non-cardiac vascular surgery (infrarenal aortic surgery), and five involved 535 participants undergoing cardiac surgery, including valvular surgery, coronary artery bypass surgery, and cardiopulmonary bypass surgery. The intervention was started from 11 days to 25 minutes before surgery in six trials and during surgery in one trial. We considered all seven RCTs to carry a high risk of bias. The effects of ACEIs or ARBs on perioperative mortality and acute myocardial infarction were uncertain because the quality of the evidence was very low. The risk of death was 2.7% in the ACEIs or ARBs group and 1.6% in the placebo group (risk ratio (RR) 1.61; 95% confidence interval (CI) 0.44 to 5.85). The risk of acute myocardial infarction was 1.7% in the ACEIs or ARBs group and 3.0% in the placebo group (RR 0.55; 95% CI 0.14 to 2.26). ACEIs or ARBs may improve congestive heart failure (cardiac index) perioperatively (mean difference (MD) -0.60; 95% CI -0.70 to -0.50, very low-quality evidence). In terms of rate of complications, there was no difference in perioperative cerebrovascular complications (RR 0.48; 95% CI 0.18 to 1.28, very low-quality evidence) and hypotension (RR 1.95; 95% CI 0.86 to 4.41, very low-quality evidence). Cardiac surgery-related renal failure was not reported. ACEIs or ARBs were associated with shortened length of hospital stay (MD -0.54; 95% CI -0.93 to -0.16, P value = 0.005, very low-quality evidence). These findings should be interpreted cautiously due to likely confounding by the clinical backgrounds of the participants. ACEIs or ARBs may shorten the length of hospital stay, (MD -0.54; 95% CI -0.93 to -0.16, very low-quality evidence) Two studies reported adverse events, and there was no evidence of a difference between the ACEIs or ARBs and control groups.

AUTHORS' CONCLUSIONS

Overall, this review did not find evidence to support that perioperative ACEIs or ARBs can prevent mortality, morbidity, and complications (hypotension, perioperative cerebrovascular complications, and cardiac surgery-related renal failure). We found no evidence showing that the use of these drugs may reduce the rate of acute myocardial infarction. However, ACEIs or ARBs may increase cardiac output perioperatively. Due to the low and very low methodology quality, high risk of bias, and lack of power of the included studies, the true effect may be substantially different from the observed estimates. Perioperative (mainly elective cardiac surgery, according to included studies) initiation of ACEIs or ARBs therapy should be individualized.

The role of zofenopril in myocardial protection during cardioplegia arrest: an isolated rat heart model

BACKGROUND

Zofenopril has beneficial effects in acute myocardial infarction, and improves the functional recovery after ischemia and reperfusion.

AIM OF THE STUDY

The aim of this study was to investigate the cardioprotective effects of zofenopril, when added to a standard cardioplegic solution or when orally administered as pretreatment.

METHODS

A Langendorff model for isolated rat hearts was employed: three groups of eight hearts each were used, respectively, with plain St. Thomas cardioplegia as control (group A and C), and the same solution added with 12.5 mg of zofenopril (group B). The third group (C) was pretreated for 7days with oral administration of zofenopril (6.5 mg/day). The hearts had a baseline perfusion for 30 minutes with Krebs-Henseleit solution at 37 degrees C, cardioplegia administration for 3 minutes, then 30 minutes of ischemia without any perfusion, and finally 30 minutes of reperfusion with Krebs-Henseleit solution at 37 degrees C.

RESULTS

Left ventricle developed pressure was significantly higher in the reperfusion period only in the pretreated group (group C) with respect to groups A and B (p = 0.016). Similar results were obtained regarding dP/dt curves (p = 0.020). No differences were demonstrated between groups for cellular viability expressed as creatine phospho-kinase (p = ns) and lactate dehydrogenase release (p = ns).

CONCLUSIONS

Zofenopril as oral pretreatment showed protective effects in an isolated model of cardioplegic arrest, although improvements in myocardial viability (enzymatic release) could not be demonstrated. Further experimental and clinical evaluations are necessary to assess the direct cardioprotective effect of zofenopril, modifying the length of treatment and the dosage of the drug.

The effect of intravenous quinaprilat on plasma cytokines and hemodynamic variables during cardiac surgery

OBJECTIVES

Perioperative treatment with angiotensin-converting enzyme (ACE) inhibitors in cardiac surgery with cardiopulmonary bypass is still controversial. Using ACE inhibitors during cardiac surgery might be associated with an increased risk of critical hypotensive episodes. On the other hand, ACE inhibitors could have beneficial effects with respect to the development of the systemic inflammatory response syndrome.

DESIGN

The effect of acute administration of quinaprilat on hemodynamic variables and plasma cytokines was assessed under double-blind, randomized, and placebo-controlled conditions.

SETTING

Department of anesthesiology and cardiovascular surgery clinic in a university hospital.

PARTICIPANTS

Forty patients without preexisting cardiac failure, undergoing coronary artery bypass grafting.

INTERVENTIONS

Patients received 0.08 mg/kg of intravenous quinaprilat or intravenous isotonic saline solution after induction of anesthesia.

MEASUREMENTS AND RESULTS

Blood samples were taken after induction of anesthesia (T0), before cardiopulmonary bypass (T1), at the end of surgery (T2), and 4 hours after the end of surgery (T3). There was no difference between the 2 groups regarding mean arterial pressure and inotropic or vasopressor support. Systemic vascular resistance index was significantly lower in the quinaprilat group at T2 (p = 0.016) and T3 (p = 0.017). No difference in proinflammatory cytokine levels was observed between the 2 groups.

CONCLUSIONS

The present investigation shows that acute administration of an intravenous ACE inhibitor, quinaprilat, has no influence on proinflammatory cytokines during cardiac surgery with cardiopulmonary bypass. The patients treated with quinaprilat showed an improved systemic vascular resistance index with no increased risk of deleterious hemodynamic episodes.

Captopril improves oxygen and glucose extraction in pig hearts during reperfusion after cold cardioplegic storage

The purpose of this study was to evaluate the haemodynamic and metabolic effects of captopril during reperfusion of pig hearts following 360 min global hypothermic cardioplegia and storage (HCS). The hearts were perfused with one litre of cold crystalloid cardioplegia (Bretschneider solution no. 3), excised and stored in saline at 4 degrees C for 360 min. The hearts were then reperfused with blood in a modified Langendorff model for 60 min. Left ventricular function, myocardial blood flow, and arteriovenous differences in oxygen, glucose and lactate were monitored intraoperatively and during reperfusion. Two groups of hearts were studied. Group I (captopril treated, n = 9): the pigs were pre-medicated with increasing oral doses of captopril for 3 weeks (12.5 mg-150 mg daily) and an intravenous dose (25 mg) upon arrival at the laboratory. Captopril was added to the cardioplegia (1000 microg/l) and to the reperfusion media (1000 microg/l). Group II (controls, n = 8): the pigs were given no premedication, captopril-free cardioplegia and the hearts were reperfused with captopril-free blood. Captopril increased myocardial oxygen and glucose extraction during reperfusion (p < 0.05 for both) while lactate remained unchanged after 360 min HCS. Treatments with captopril increased developed left ventricular pressure (DLVP) and relaxation (-dP/dtmax) during reperfusion (p < 0.05 for both), while contractility (+dP/dtmax) was unchanged. Heart rate was reduced in captopril-treated hearts (p < 0.05) while myocardial blood flow (MBF) was similar in the two groups. Captopril administration prior to and during HCS and postcardioplegic reperfusion improves oxygen and glucose extraction in large spontaneously beating porcine hearts during reperfusion. The underlying mechanisms seem to involve metabolic modulation, since myocardial uptake of oxygen and glucose was increased in the absence of changes in myocardial blood flow.

Captopril-induced glutamate release at the start of reperfusion after cold cardioplegic storage of pig hearts

OBJECTIVE

We sought to evaluate the effects of captopril on glucose-related metabolism during hypothermic cardioplegic storage and subsequent reperfusion.

METHODS

We compared hearts from control pigs with hearts from pigs treated with increasing oral doses of captopril for 3 weeks (12.5-150 mg daily), an intravenous bolus (25 mg) before operation, and captopril-containing cardioplegic solution (1 mg/L). The hearts were excised after infusion of cold crystalloid cardioplegic solution and stored in saline solution (4 degrees C-6 degrees C). In one series we studied myocardial blood flow and arteriovenous differences in oxygen, glucose, lactate, glutamate, and alanine during 60 minutes of postcardioplegic blood reperfusion. In this series captopril-treated hearts were reperfused with captopril-containing blood (1 mg/L). In another series we obtained biopsy specimens from the left ventricle throughout 30 hours of hypothermic cardioplegic storage and monitored tissue content of energy-rich phosphates, glycogen, glutamate, and alanine.

RESULTS

Captopril increased glutamate and alanine release 11- to 17-fold at the start of reperfusion (P <.001). Furthermore, captopril increased myocardial oxygen and glucose uptake during reperfusion (P <.001 for both), whereas lactate release and myocardial blood flow were unaffected by captopril. At the start of reperfusion, there was a positive correlation between glutamate release and glucose uptake in captopril-treated hearts (r = 0.66, P =.05). We found no statistically significant differences between captopril and control hearts in tissue content of adenosine triphosphate, glycogen, glutamate, alanine, or lactate during 30 hours of cardioplegic storage.

CONCLUSIONS

The metabolic effects of captopril are strictly related to reperfusion, during which oxidative metabolism of glucose is improved. The captopril-induced increase in glutamate and alanine release at the start of reperfusion after cardioplegic storage may reflect a switch in metabolism of glucose-related amino acids.

Does the addition of losartan improve the beneficial effects of ACE inhibitors in patients with anterior myocardial infarction? A pilot study

OBJECTIVE

To verify the efficacy of the combination of captopril (75 mg day) and losartan (25 mg/day) in early postinfarction phases of reperfused anterior acute myocardial infarction.

DESIGN AND PATIENTS

99 patients, hospitalised for suspected anterior acute myocardial infarction within four hours from the onset of symptoms, were randomised into two groups: group A included 50 patients who received captopril 75 mg/day and placebo; group B included 49 patients who received captopril 75 mg/day within three days of admission plus losartan 12.5 mg, as a first dose, and 25 mg/day successively. An additional 23 patients with anterior acute myocardial infarction received losartan 25 mg alone and acted as controls (group C) to check the effects of losartan on plasma angiotensin II (AII) concentrations. Noradrenaline (norepinephrine) (NA) and AII plasma concentrations were measured on the third and 10th day after admission in 93 patients (35 from group A, 35 from group B, and 23 from group C). 90 days after admission patients underwent echocardiography to determine end systolic volume (ESV) and ejection fraction (EF).

RESULTS

Patients in groups A and B were similar with regard to age, sex, creatine kinase peak, EF, ESV, and risk factors. Group B (captopril plus losartan) patients showed a significant reduction in mean (SD) systolic blood pressure within the group (basal 128 (10) mm Hg; 10 days after admission 105 (9) mm Hg, p < 0.001), and in comparison with group A (captopril) patients (basal 127 (11) mm Hg; 10 days after admission 116 (10) mm Hg, p < 0. 001). Diastolic blood pressure was also lower in group B patients versus group A (66 (11) v 77 (11) mm Hg). Group C (losartan) patients also showed a significant reduction in systolic blood pressure (131 (13) mm Hg down to 121 (12) mm Hg, p < 0.001). Neither NA nor AII plasma concentrations in groups A and B differed significantly in basal samples (NA 673 (138) v 675 (141) pg/ml; AII 12.77 (4.79) v 12.65 (4.71) pg/ml) or 10 days after admission (NA 283 (93) v 277 (98) pg/ml; AII 5.31 (2.25) v 6.09 (3.31) pg/ml). However, patients in group C had higher plasma concentrations of AII (14.79 (5.7) pg/ml on the third day and 7.98 (4.92) pg/ml on the 10th day) than patients in either group A or B (p = 0.006). After 90 days following treatment, group B (captopril plus losartan) patients had a smaller ESV than patients in group A (captopril) and group C (losartan).

CONCLUSION

The data suggest that the combination of captopril plus losartan is feasible in the early treatment of acute myocardial infarction patients, and it appears that this combination has more effect on ESV than captopril alone in the short term.

Attenuation of ischemia--reperfusion injury by enalapril maleat

1. The aim of this study was to investigate the effects of enalapril maleate on ischemia-reperfusion injury of the myocardium, after cardioplegic arrest in isolated guinea pig hearts, in a modified Langendorff model. 2. Animals were subjected to 90 min of normothermic global ischemia, followed by 30 min of reperfusion. Cardioplegic arrest was achieved by administering St. Thomas Hospital cardioplegic solution (STHCS). 3. The hearts were randomly allocated into four groups (n=8 in each group). The first group was utilized as control. In the second group, oral pretreatment was made (0.2 mg/kg enalapril maleat was given twice a day for 10 days). In the third group, enalapril maleat (1 micromol/l) was added to STHCS. In the fourth group, hearts were arrested with enalapril maleat-enriched STHCS, and enalapril maleat-enriched (1 micromol/l) Krebs-Henseleit solution was applied during the reperfusion period. 4. Although the study groups showed better recovery of contractility than did the control group, in the last group, the hearts had the best recovery of left ventricular systolic function, where dp/dt maximum was 89.7+/-6.9% of the preischemic values. Group 1, group 2 and group 3 achieved 44.2+/-4.5%, 79.4+/-5.8% and 68.1+/-6.7% of their preischemic dp/dt values. A similar observation was found for left ventricular developed pressure (LVDP); LVDP values were 52.4+/-2.1% (in group 1), 79.6+/-2.8% (in group 2), 72.8+/-4.6% (in group 3) and 86.7+/-5.8% (in group 4) of control after reperfusion. Creatine kinase leakage was significantly lower and postischemic coronary flows were significantly higher in group 4. 5. We concluded that usage of enalapril maleat in the reperfusion period was more effective for improving myocardial recovery after cardioplegic arrest. The additional protective effects of enalapril maleat not only were by angiotensin-converting-enzyme-inhibition-dependent coronary vasodilation and thiol-dependent limitation of oxidative injury, but could also be related to an oxygen-free-radical-scavenging effect.

Beneficial effect of captopril against ischaemia-reperfusion injury in isolated guinea pig hearts

The study was designed to clarify whether captopril, an angiotensin-coverting enzyme inhibitor, will reduce the injury of global ischaemia and reperfusion after cardioplegic arrest in isolated guinea pig hearts, in a modified Langendorff model. The hearts were randomly allocated into four groups (n = 10 in each) and subjected to 90 min of normothermic global ischemia, followed by 30 min of reperfusion; in all groups, cardioplegic arrest was achieved by administering St. Thomas's Hospital cardioplegic solution (STHCS). The first group was utilized as the control group. In the second group, captopril (200 mumol/L) was added to STHCS. In the third group, oral pretreatment was carried out (0.3 mg/kg captopril was given twice a day for 10 days). In the fourth group, oral pretreatment was achieved and captopril-enriched solution was applied in the first 5 min of reperfusion. Although the study groups showed better recovery of contractility than the control group, in the fourth group the hearts had the best left ventricular contractile function, where contractile force (g contractility/g heart weight) was 55.4% +/- 3.8% of the preischameic values. Groups I, II, and III achieved 31.0% +/- 3.2%, 41.6% +/- 3.8%, and 48.3% +/- 3.9% of their preischaemic contractile force values. Creatine kinase leakage was significantly lower and postischaemic coronary flows, too, were significantly higher in the fourth group. Coronary flow after reperfusion increased from 48.5 +/- 6.7 to 65.2 +/- 7.1 ml/min g heart in group 4 (p < 0.05). Myocardial lipid peroxides and glutathione contents showed that there was a correlation between the depletion of myocardial glutathione content and increased lipid peroxidation. These preliminary results showed that: the addition of captopril to reperfusion solution and oral preconditioning improved post-ischameic myocardial function and decreased myocardial injury.

Captopril does not affect plasma endothelin-1 during thrombolysis and reperfusion

Studies showed that endothelin-1 (ET-1) was increased in the acute myocardial infarction (AMI). Experimental studies reported that captopril was able to reduce ET-1 secretion, and that ET-1 was increased during reperfusion. This study was aimed to verify if captopril was able to reduce plasma ET-1 during thrombolysis in AMI. Seventy-three patients, hospitalized for suspected AMI within 4 h from the onset of symptoms suitable for thrombolysis (1st episode), Killip class 1-2, were randomized (double blind) into two groups: group 1 (37 pts), 8 F/29 M, received captopril, 6.25 mg, orally 15 min before thrombolysis. Group 2: (36 pts) 8 F/28 M, received placebo before thrombolysis. All patients met the reperfusion criteria. Plasma ET-1 were checked on admission, at 1 h and at 2 h, after starting thrombolysis. Group 1 contained ten unstable angina, 17 anterior and ten inferior AMIs. Group 2 contained ten unstable angina, 16 anterior and ten inferior AMIs. Mean concentrations of ET-1: Unstable angina: group 1, basal--4.56, at 1 h--4.47, 2 h--5.89 pg/ml; group 2: basal--4.17, at 1 h--4.59, 2 h--5.24 pg/ml. Inferior AMI: group 1: basal--6.87, 1 h--7.75, 2 h--8.47; group 2: basal--6.34, 1 h--6.68, 2 h--7.98 pg/ml. Anterior AMI: group 1: basal--7.17, 1 h--7.93, 2 h--10.76 pg/ml (between basal and 2-h samples P < 0.05); group 2: basal--7.46, 1 h--7.51, 2 h--10.74 pg/ml. Differences between the two groups were not significant. Our data suggest that captopril does not affect plasma ET-1 during thrombolysis.