Acute hemodynamic interaction of aspirin and ticlopidine with enalapril: results of a double-blind, randomized comparative trial

Racial Differences in Over-the-Counter Non-steroidal Anti-inflammatory Drug Use Among Individuals at Risk of Adverse Cardiovascular Events

PURPOSE

Black Americans are disproportionately affected by adverse cardiovascular events (ACEs). Over-the-counter (OTC) non-steroidal anti-inflammatory drugs (NSAIDs) confer increased risk for ACEs, yet racial differences in the use of these products remain understudied. This study sought to determine racial differences in OTC NSAID and high-potency powdered NSAID (HPP-NSAID) use.

METHODS AND MATERIALS

This retrospective analysis examined participants at risk of ACEs (defined as those with self-reported hypertension, diabetes, heart disease, or smoking history ≥ 20 years) from the North Carolina Colon Cancer Study, a population-based case-control study. We used multivariable logistic regression models to assess the independent associations of race with any OTC NSAID use, HPP-NSAID use, and regular use of these products.

RESULTS

Of the 1286 participants, 585 (45%) reported Black race and 701 (55%) reported non-Black race. Overall, 665 (52%) reported any OTC NSAID use and 204 (16%) reported HPP-NSAID use. Compared to non-Black individuals, Black individuals were more likely to report both any OTC NSAID use (57% versus 48%) and HPP-NSAID use (22% versus 11%). In multivariable analyses, Black (versus non-Black) race was independently associated with higher odds of both NSAID use (OR 1.4, 95% CI (1.1, 1.8)) and HPP-NSAID use (OR 1.8 (1.3, 2.5)).

CONCLUSIONS

Black individuals at risk of ACEs had higher odds of any OTC NSAID and HPP-NSAID use than non-Black individuals, after controlling for pain and socio-economic status. Further research is necessary to identify potential mechanisms driving this increased use.

Interaction between cyclooxygenase and the renin-angiotensin-aldosterone system: rationale and clinical relevance

Increased understanding of pathophysiological mechanisms of cardiovascular diseases has shown that the renin-angiotensin-aldosterone system (RAAS) is activated in this setting and suggests a central role for the angiotensin-converting enzyme (ACE). ACE transforms angiotensin I (Ang I) to angiotensin II (Ang II), and also promotes the degradation of bradykinin into inactive metabolites. These bradykinins stimulate nitric oxide synthesis and vasodilatator prostaglandin synthesis via a cyclooxygenase (COX) pathway.

COX inhibitors may therefore be deleterious in cardiovascular disease and/or counteract part of ACE inhibitor (ACE-I) efficacy. This has been clearly demonstrated with non-steroidal anti-inflammatory drugs (NSAIDs), including high-dose aspirin, in avoiding their use in such patients. hypertension, coronary artery disease and chronic heart failure (CHF); most guidelines recommend avoiding their use in such patients.

Theoretically, this effect is dose-mediated and the existence of an identical deleterious effect with low-dose aspirin has been an area of intense debate. In this article, we review studies, most of them conducted in CHF, that pointed out such a possible deleterious effect and a counteraction of ACE-Is with low-dose aspirin , using various criteria of assessment.

However, there are no prospective long-term studies that have validated such an effect, and the role of other anti-aggregating agents has not been evaluated. Until such studies are published, the use of low-dose aspirin (100 mg/day) in such patients can be recommended.

Warfarin and aspirin in patients with heart failure and sinus rhythm

BACKGROUND

It is unknown whether warfarin or aspirin therapy is superior for patients with heart failure who are in sinus rhythm.

METHODS

We designed this trial to determine whether warfarin (with a target international normalized ratio of 2.0 to 3.5) or aspirin (at a dose of 325 mg per day) is a better treatment for patients in sinus rhythm who have a reduced left ventricular ejection fraction (LVEF). We followed 2305 patients for up to 6 years (mean [±SD], 3.5±1.8). The primary outcome was the time to the first event in a composite end point of ischemic stroke, intracerebral hemorrhage, or death from any cause.

RESULTS

The rates of the primary outcome were 7.47 events per 100 patient-years in the warfarin group and 7.93 in the aspirin group (hazard ratio with warfarin, 0.93; 95% confidence interval [CI], 0.79 to 1.10; P=0.40). Thus, there was no significant overall difference between the two treatments. In a time-varying analysis, the hazard ratio changed over time, slightly favoring warfarin over aspirin by the fourth year of follow-up, but this finding was only marginally significant (P=0.046). Warfarin, as compared with aspirin, was associated with a significant reduction in the rate of ischemic stroke throughout the follow-up period (0.72 events per 100 patient-years vs. 1.36 per 100 patient-years; hazard ratio, 0.52; 95% CI, 0.33 to 0.82; P=0.005). The rate of major hemorrhage was 1.78 events per 100 patient-years in the warfarin group as compared with 0.87 in the aspirin group (P<0.001). The rates of intracerebral and intracranial hemorrhage did not differ significantly between the two treatment groups (0.27 events per 100 patient-years with warfarin and 0.22 with aspirin, P=0.82).

CONCLUSIONS

Among patients with reduced LVEF who were in sinus rhythm, there was no significant overall difference in the primary outcome between treatment with warfarin and treatment with aspirin. A reduced risk of ischemic stroke with warfarin was offset by an increased risk of major hemorrhage. The choice between warfarin and aspirin should be individualized. (Funded by the National Institute of Neurological Disorders and Stroke; WARCEF ClinicalTrials.gov number, NCT00041938.).

Does aspirin use adversely influence intermediate-term postdischarge outcomes for hospitalized patients who are treated with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers? Findings from Organized Program to Facilitate Life-Saving Treatment in Hospitalized Patients with Heart Failure (OPTIMIZE-HF)

BACKGROUND

Conflicting data exist regarding a potential deleterious association between aspirin (ASA) and angiotensin-converting enzyme inhibitors (ACEIs) when used concurrently in patients with heart failure (HF). How such an interaction may be influenced by underlying etiology of HF and whether it extends to patients treated with angiotensin receptor blockers (ARBs), however, are not known.

METHODS

Eligible patients from the OPTIMIZE-HF registry were dichotomized into those with ischemic or nonischemic HF. Potential associations between ASA and ACEI or ARB use and 60- to 90-day postdischarge outcomes were assessed using Cox proportional and logistic regression modeling. Models were adjusted for factors known to influence the outcome of interest and by propensity score for ACEI or ARB prescription after an index HF admission.

RESULTS

Mortality was not increased (hazard ratio [95% CI]) when ASA was used in conjunction with ACEI (0.51 [0.29-0.87]) or ARB (0.29 [0.09-0.96]) in patients with ischemic or nonischemic (ACEI 0.71 [0.42-1.21], ARB 1.42 [0.74-2.74]) HF. Regression model parameter estimates trended toward harm reduction, but interaction terms for mortality and a composite of mortality or rehospitalization were nonsignificant (P for all >.05).

CONCLUSIONS

When combined with ACEI or ARB, ASA had no demonstrable adverse effect on intermediate-term postdischarge outcomes for patients with ischemic or nonischemic HF.

Effects of aspirin and clopidogrel on plasma brain natriuretic peptide in patients with heart failure receiving ACE inhibitors

BACKGROUND

By inhibiting prostaglandins, aspirin may be deleterious in heart failure (HF) and/or may counteract angiotensin-converting enzyme (ACE) inhibitor efficacy. Conversely, clopidogrel has no effect on prostaglandin metabolism.

AIM

To investigate the effect of aspirin and clopidogrel on brain natriuretic peptide (BNP) levels in HF patients treated with ACE inhibitors.

METHODS

36 patients with stable HF (65+/-13 years, 24 males/12 females, NYHA class II to IV, ejection fraction <40%, 13 with coronary disease, all treated with ACE inhibitors) were enrolled in this prospective, double-blind study and randomised to aspirin 325 mg/day or clopidogrel 75 mg/day for 14 days. BNP was determined at day 0 and day 14.

RESULTS

19 patients were randomised to aspirin and 17 to clopidogrel. Baseline characteristics were similar in both groups. BNP levels increased in the aspirin group from day 0 to day 14 (107+/-103 to 144+/-149 pg/ml, p=0.04) whereas clopidogrel had no effect (104+/-107 and 97+/-99 pg/ml respectively, p=0.61).

CONCLUSION

This study demonstrates an adverse effect of aspirin 325 mg/day on BNP plasma levels in HF patients treated with ACE inhibitors. In contrast clopidogrel 75 mg/day had no effect.

Improving the management of patients after myocardial infarction, from admission to discharge

BACKGROUND

Recent developments in pharmacologic and device therapy, as well as initiatives to increase the use of standard orders and promote in-hospital communication, have improved the care of patients with myocardial infarction (MI). The increased presence of hospitalists, physicians who provide in-hospital care as a specialty, promises to provide further improvements.

OBJECTIVE

This article reviews current information on evidence-based care of the hospitalized MI patient, with a particular emphasis on identifying left ventricular dysfunction (LVD) and appropriate treatments.

METHODS

MEDLINE was searched for all large-scale clinical trials providing information on the care of post-MI patients with or without LVD and/or heart failure (HF), with no limit on time period. The search terms were post-myocardial infarction, large-scale, randomized, clinical trial, left ventricular dysfunction, and/or heart failure. All trials investigating therapies currently recommended in the American College of Cardiology/American Heart Association ST-elevation MI (ACC/AHA STEMI) guidelines and including post-MI patients with or without LVD and/or HF, as indicated by signs and symptoms of HF or Killip class, were included.

RESULTS

In the acute setting, the ACC/AHA STEMI guidelines recommend the use of aspirin, clopidogrel, beta-blockers, angiotensin-converting enzyme inhibitors, heparin (low molecular weight or unfractionated), and glycoprotein IIb/IIIa inhibitors (if the patient is undergoing a percutaneous coronary intervention). The guidelines recommend use of aldosterone antagonists and statins at discharge, in addition to continuation of all acute therapies. The ACC/AHA guidelines apply to all patients after MI and do not specify whether the recommended therapies are effective in post-MI patients with LVD or HE Reviewing the trials that included post-MI patients with LVD and/or HF, it appears that in some cases, only certain agents within a class have been evaluated (eg, post-MI beta-blocker trials often excluded patients with LVD, and the efficacy of atenolol has not been evaluated in post-MI patients with LVD or HF), and some agents have not shown as much efficacy as others in this high-risk patient population (eg, metoprolol appeared to be associated with poorer outcomes in this population than carvedilol). Rather than recommending an entire class, hospital care maps and critical-care pathway tools should incorporate the use of evidence-based agents.

CONCLUSIONS

The use of evidence-based care in the hospital has the potential to substantially reduce morbidity and mortality in post-MI patients with LVD and/or HE The hospitalist can facilitate the best practices and best care of the post-MI patient through the use of in-hospital critical-care pathway tools.

Clopidogrel Is Associated With a Lesser Increase in NT-proBNP When Compared to Aspirin in Patients With Ischemic Heart Failure

BACKGROUND

Aspirin has been associated with adverse heart failure outcomes, probably because of a blunting interaction with angiotensin-converting enzyme (ACE) inhibitors. Therefore, we hypothesized that clopidogrel when compared with aspirin would be associated with a slower progression of heart failure as determined by levels of amino-terminal pro-brain natriuretic peptide (NT-proBNP).

METHODS AND RESULTS

In an open-label, randomized, 2-treatment, 2-period crossover study, 18 patients with ischemic heart failure (14 post-myocardial infarction, left ventricular ejection fraction 0.32 +/- 0.08), median age 73, New York Heart Association class II (11 patients) or III (7 patients), all taking ACE inhibitors were included. Patients were randomized to 8 weeks of aspirin 100 mg/day followed by 8 weeks of clopidogrel 75 mg/day, or the reversed sequence. Blood levels of NT-proBNP were measured using sandwich immunoassay. Patients on aspirin experienced an 8-times greater increase in log-transformed values of NT-proBNP compared with patients on clopidogrel (average change 4.757% versus 0.597%; P = .0395 for intervention, P = .4453 for period, P = .4046 for sequence). We observed no change in functional class, 6-minute walking test, creatinine levels, or electrolytes.

CONCLUSION

Aspirin is associated with a greater increase in natriuretic peptides (log-transformed NT-proBNP levels), implying that aspirin therapy is associated with a more progressive course of heart failure.

Comparative effect of aspirin and clopidogrel on arterial function in CHF

BACKGROUND

By inhibiting prostaglandins, aspirin may be deleterious in congestive heart failure (CHF) and/or partially counteract the efficacy of angiotensin-converting enzyme inhibitors (ACEI). Conversely, clopidogrel has no effect on prostaglandin metabolism. The aim of this study was to prospectively investigate the effect of aspirin and clopidogrel on arterial functional properties in CHF patients treated with ACEI.

METHODS

Forty-five patients with stable NYHA class II-IV CHF (64.0+/-15.5 years), ejection fraction <40%, were included in this prospective double-blind study and randomized to receive aspirin 325 mg/day or clopidogrel 75 mg/day for 14 days. Reflected wave assessed by radial applanation tonometry and pulse wave velocity (PWV) were measured at day 0 and day 14.

RESULTS

Aspirin resulted in an increase in the augmentation index of the reflected wave (Delta=+3.5+/-5.2%, p=0.005) and the height above the shoulder of the reflected wave (Delta=+1.7+/-3.1 mm Hg, p=0.023), without statistically variation in PWV. Conversely, clopidogrel had no effect on the same parameters (p=0.512, p=0.677 and 0.801, respectively). Overall, variations in the augmentation index of reflected wave significantly differed when compared aspirin with clopidogrel (p=0.0261).

CONCLUSION

This study demonstrates the existence of a negative effect of aspirin 325 mg/day when compared to clopidogrel 75 mg/day on arterial functional properties in CHF patients treated with ACEI.

Aspirin Inhibits the Acute Arterial and Venous Vasodilator Response to Captopril in Patients with Chronic Heart Failure

PURPOSE

The potentially beneficial hemodynamic effects of angiotensin-converting enzyme (ACE) inhibitors in heart failure may relate, in part, to their ability to increase the production of vasodilator prostanoids. Low dose aspirin is commonly prescribed in CHF and may attenuate the vasodilator effects of ACE inhibitors. We sought to determine the effects of low dose aspirin on the peripheral hemodynamic effects of captopril in patients with chronic heart failure (CHF).

METHODS

Nine patients with chronic heart failure were randomized in a placebo controlled, cross over study, to 75 mg of aspirin daily or placebo. After 7 days treatment the response to 25 mg of captopril was evaluated over 180 min using venous occlusion plethysmography. Forearm blood flow (FBF) and forearm venous capacitance (FVC) were measured.

RESULTS

Mean arterial pressure and heart rate did not change. After placebo, FBF increased in response to captopril (+18%, 95%CI 24.2, 11.8), a response inhibited by aspirin (-1.4%, 2.9, -5.7), p < 0.005. After placebo, FVC increased in response to captopril (+7.6%, 9.8, 5.4), which was also inhibited by aspirin (+2.0%, 4.6, -0.6), aspirin vs. placebo, p = 0.02).

CONCLUSION

In patients with chronic heart failure even low dose aspirin inhibits both the acute arterial and venous dilator responses to captopril. This action of aspirin may reduce the long-term clinical benefits of ACE inhibitors.

Aspirin Use in Chronic Heart Failure

There has been ongoing controversy as to whether aspirin should be used in patients with chronic heart failure (CHF). The argument for aspirin is that many patients have underlying coronary disease, and aspirin prevents reinfarction and other vascular events. Arguments against the routine use of aspirin are that many CHF patients do not have underlying coronary disease, and that the benefit of aspirin lessens after the first 6 to 12 months after infarction. Also, several analyses suggest that aspirin may actually worsen outcomes in CHF patients, possibly because it inhibits prostaglandins, with resulting adverse hemodynamic and renal effects. Two recent prospective randomized studies have found that aspirin is associated with more frequent hospitalizations for worsening heart failure, although it did not have an adverse effect on vascular events. These results suggest that aspirin should not be routinely used in CHF patients and be avoided in those with refractory CHF, but that it may be beneficial in patients with recent infarction or multiple vascular risk factors.

[Antihypertensive drug-drug interactions]

A drug interaction is the quantitative or qualitative modification of the effect of a drug by the simultaneous or successive administration of a different one. Hypertensive patients, mainly the more elderly ones, frequently present concomitant diseases that require the administration of several medicines which facilitates the appearance of interactions. The lack of effectiveness of the antihypertensive treatment is a relatively frequent fact that sometimes is due to interactions of antihypertensive drugs with other treatments. It is difficult to determine the incidence of interactions, but it is related to the number of drugs administered simultaneously. Between 37 and 60% of hospital-admissions are treated with potentially dangerous drug associations and up to a 6% of fatal events are due to this circumstance. Among antihypertensive drugs, diuretics and angiotensin converting enzyme inhibitors are less affected by drug-interactions. Lipophilic beta-blockers agents may present some clinical relevant interactions, whereas calcium channel blockers, especially the non-dihydropiridinic ones, are implied in clinically relevant pharmacokinetic interactions. Among the angiotensin receptor blockers there are differences that would have to be considered when they are used in patients who receive other drugs. Although it is impossible for the doctor to remember all the clinical relevant interactions, it is important to bear in mind their existence and the possible mechanisms of production which can help to identify them and to contribute to their prevention. The most frequent interactions related with clinical problems are the pharmacokinetic ones, mainly those related to the metabolism through the cytochrome P450 system or the presystemic clearance by means of the P-glycoprotein. Enzymes of the cytochrome P450 system may present polymorphisms that can explain the individual differences in the response to drugs or the appearance of drug-interactions.

Endothelial action of thienopyridines and thienopyrimidinones in the isolated guinea pig heart

Antiplatelet thienopyridines (ticlopidine, clopidogrel) and their thienopyrimidinone congeners, induce prostacyclin-dependent thrombolysis in vivo. Here we tested whether thienopyridines (ticlopidine, clopidogrel, and its enantiomer without antiplatelet properties) and structurally related thienopyrimidinones release NO from coronary endothelium in the isolated guinea pig heart, perfused according to Langendorff technique. The involvement of endothelium-derived NO in coronary vasodilation induced by these agents was assessed by effect of L-N(G)-nitro-arginine methyl ester (L-NAME). In addition, effect of thienopyridines or thienopyrimidinones on nitrite accumulation in cultured endothelium was assayed. Tienopyridines (10-100 micromol L(-1)) and thienopyrimidinones (10-30 micromol L(-1)) produced concentration-dependent increase in coronary flow comparable to that induced by acetylcholine (0.1 micromol L(-1)) or bradykinin (3 nmol L(-1)) which was inhibited by L-NAME (by 50-70%) but not by indomethacin. Furthermore, thienopyridines and thienopyrimidinones caused NO release from cultured endothelial cells. In conclusion, both thienopyridines independently from their antiplatelet action and their thienopyrimidinone congeners that are devoid of antiplatelet action stimulate coronary endothelium to release NO. Endothelial action of these compounds merits further investigation.

Angiotensin Antagonism in Coronary Artery Disease

The renin-angiotensin system (RAS) is an ancient and complex cascade of homeostatic reactions aimed at regulating primordial functions that ensure organ perfusion through the control of blood pressure and the regulation of renal-cardiac activity. However, the over-expression or lack of compensatory mechanisms of any of its components may initiate detrimental effects that potentially lead to disease, a balance that makes the RAS a sequence with a labile physiological equilibrium and with a strong harm potential. These characteristics of the RAS in general, and of the angiotensin converting enzyme (ACE) in particular, make it not only an important complex for the regulation of blood pressure and neuropeptide metabolism, but also a fascinating subject of study from a biochemical, evolutionary and genetic point of view. Pharmacological interventions that influence the RAS by inhibiting the ACE or the angiotensin II type 1 receptor (AT1R) have demonstrated sustained efficacy in reducing the incidence of cardiovascular events and, consequently, vascular mortality in several clinical situations. ACE inhibitors and angiotensin II receptor antagonists (ARAs) reduce blood pressure and have cardio- and vasculoprotective effects. Anti-atherosclerotic effects have also been attributed to these drugs. For these reasons, it has been hypothesised that RAS inhibitors could also reduce the recurrence of ischaemic events after myocardial revascularisation procedures, namely coronary artery by-pass graft surgery (CABG) or percutaneous coronary interventions (PCI). Information available on the effect of ACE inhibitors and ARAs in patients with coronary artery disease (CAD) previously treated with revascularisation techniques indicates a substantial reduction of mortality and infarction in these patients. However, data regarding the progression of CAD, restenosis or reocclusion of vascular conduits of the coronary circulation after myocardial revascularisation are inconsistent. In most studies, the administration of ACE inhibitors neither improved the ischaemic threshold nor reduced the need for new revascularisation procedures. On the contrary, ACE inhibitors have been associated with higher restenosis rates after PCI in some retrospective series. Conversely, a single, exploratory randomised trial demonstrated that the selective AT1R antagonist valsartan significantly reduced stent restenosis after PCI. In patients undergoing CABG, ACE inhibitors did not reduce the risk of graft degeneration or occlusion. Studies that evaluated a possible anti-atherosclerotic effect of ACE inhibitors (including some large randomised trials) have generally been negative.

Antihypertensive therapy: special focus on drug interactions

Today, the lifetime risk of patients aged 55-65 years to receive antihypertensive drugs approaches 60%. Yet, recent trials suggest that hypertension is not adequately controlled in the majority of patients. The prevalence of hypertension increases with advancing age, as does the prevalence of comorbid conditions and the total number of medications taken. Multi-drug therapy, advancing age and comorbid conditions are also key risk factors for adverse drug reactions and drug interactions. In this review, the authors evaluate the most frequently used antihypertensive drugs (diuretics, beta-adrenergic blockers, angiotensin-converting enzyme inhibitors, calcium channel blockers, angiotensin II receptor Type 1 blockers and alpha-adrenergic blockers) with special reference to pharmacodynamic and pharmacokinetic drug interactions. As the spectrum of drugs prescribed is constantly changing, safety yesterday does not imply safety today and safety today does not imply safety tomorrow. Furthermore, therapeutic efficacy should not be neglected over concerns regarding drug interactions. Many patients are at risk of clinically relevant drug interactions involving antihypertensive drugs but, presently, even more patients may be at risk of suffering from the consequences of their inadequately treated hypertension. In this respect, the authors discuss controversial viewpoints on the overall clinical relevance of drug interactions occurring at the level of cytochrome P450 metabolism.

The Warfarin and Antiplatelet Therapy in Heart Failure Trial (WATCH): rationale, design, and baseline patient characteristics

BACKGROUND

The role of anticoagulation in patients with chronic heart failure has long been an area of interest and controversy. Traditionally the goal of anticoagulation has been to prevent embolic events, but recent trials also demonstrated that oral anticoagulation also prevents vascular events in patients with prior myocardial infarction, who constitute the majority of heart failure patients. Although antiplatelet agents also reduce postinfarction vascular events, few data are available in heart failure patients, and some evidence suggests that aspirin may also have the potential to worsen heart failure morbidity and mortality, possibly by interfering with the effects of angiotensin-converting enzyme inhibitors. Methods and results The Warfarin and Antiplatelet Therapy in Chronic Heart Failure (WATCH) trial was undertaken to determine the optimal antithrombotic agent for heart failure patients. WATCH was a prospective-randomized trial in which symptomatic heart failure patients in sinus rhythm with ejection fractions < or =35% taking angiotensin-converting enzyme inhibitors (unless not tolerated) and diuretics were randomized to open-label warfarin (target International Normalized Ratio 2.5-3.0) or double-blind antiplatelet therapy with aspirin 162 mg or clopidogrel 75 mg. Two primary comparisons were specified: anticoagulation with warfarin versus antiplatelet therapy with aspirin and antiplatelet therapy with clopidogrel versus antiplatelet therapy with aspirin. The primary outcome is the composite of death from all causes, nonfatal myocardial infarction, and nonfatal stroke analyzed as time to first event using the intent-to-treat approach. The secondary endpoint was the broader composite of death from all causes, nonfatal myocardial infarction, non-fatal stroke, and hospitalizations for worsening heart failure, unstable angina pectoris, and systemic or pulmonary artery embolic events. Additional prespecified analyses include heart failure events, coronary events, and resource utilization.

CONCLUSIONS

Although the trial was designed to enter 4500 patients, it was terminated 18 months prematurely in June 2003 by the VA Cooperative Study Program because of poor enrollment with a resulting reduction of its power to achieve its original objective. This manuscript describes the study rationale, protocol design, and the baseline characteristics of the 1587 patients who were entered into the study. The WATCH trial will help define the optimal approach to antithrombotic therapy in the contemporary management of patients with chronic heart failure resulting from left ventricular systolic dysfunction.

Aspirin does not adversely affect survival in patients with stable congestive heart failure treated with Angiotensin-converting enzyme inhibitors

BACKGROUND

Experimental studies and retrospective analyses of mortality trials with angiotensin-converting enzyme inhibitors (ACE-Is) have suggested that aspirin may reduce the beneficial effect of these drugs. The aim of this study was to assess a possible detrimental effect of aspirin on survival in stable patients with left ventricular systolic dysfunction who had congestive heart failure and had been treated with ACE-Is.

METHODS AND RESULTS

We performed a retrospective analysis in 755 consecutive stable patients with left ventricular systolic dysfunction. A Cox regression model was used to select independent predictors of survival and to test for a possible interaction between aspirin and ACE-Is with an adjustment to differences in clinical characteristics in subgroups of patients. Of the 755 patients, 328 (43.4%) had proven ischemic cardiomyopathy, 693 patients (91.8%) were receiving ACE-Is, and 317 patients were receiving aspirin (mean [+/- SD] dose, 183 +/- 65 mg/d; 74% of the patients receiving < or = 200 mg/d). During a median follow-up period of 1,996 days, there were 273 cardiac-related deaths, 14 urgent transplantations, 71 nonurgent transplantations, and 46 noncardiac-related deaths, and 3 patients were lost to follow-up. The cardiovascular mortality rates were 11.5% and 19.0%, respectively, at 1 and 2 years. There were no interactions among aspirin, ACE-Is, and survival in the overall population (p = 0.21), or in subgroups of patients with ischemic cardiomyopathy (p = 0.41) or with nonischemic cardiomyopathy (p = 0.74).

CONCLUSIONS

In this population of stable patients with left ventricular systolic dysfunction, our retrospective analysis did not demonstrate any interaction between the use of aspirin and survival in patients receiving ACE-Is.

Should aspirin be used with angiotensin-converting enzyme inhibitors in patients with chronic heart failure?

Aspirin and angiotensin-converting enzyme (ACE) inhibitors are widely used in combination to treat a wide spectrum of cardiac disorders. Theoretically, a rationale for interaction between these two agents exists in the possible counterbalancing prostaglandin inhibiting actions of aspirin and the vasodilatory prostaglandin promoting effects of ACE inhibitors. Animal and human studies suggest such an interaction, but most are plagued by small numbers or retrospective designs. Large-scale trials are in progress to address this issue. Until then, the key factor in deciding whether a patient with ischemic heart disease on ACE inhibitor therapy should be placed on aspirin therapy may largely depend on the severity of heart failure. The more severe the heart failure, the more likely an appreciable interaction between aspirin and ACE inhibitors will occur. Treatment with either low-dose aspirin or with alternative agents, such as warfarin or clopidogrel, may be the best therapeutic approach for patients with severe systolic heart failure.

Aspirin alters arterial function in patients with chronic heart failure treated with ACE inhibitors: a dose-mediated deleterious effect

BACKGROUND

By inhibiting prostaglandin synthesis, aspirin can interfere with both arterial functional and angiotensin-converting enzyme inhibitor (ACEI) properties and be deleterious in chronic heart failure (CHF).

AIM

Our aim was to prospectively evaluate the effect of aspirin on arterial functional properties in CHF patients treated with ACEIs.

METHODS AND RESULTS

Over three consecutive treatment periods of 7 days, 18 patients received placebo, followed by aspirin 100 mg/day, and then aspirin 325 mg/day. Single blind prospective assessment of reflected wave and time reflection by radial applanation tonometry; pulse wave velocity; blood pressure; thromboxane B2 (TxB2) and prostaglandins in plasma and urine was performed. Aspirin 325 mg/day induced a significant increase in augmentation index of reflected wave (P<0.0001 and P=0.0013 vs. placebo and aspirin 100 mg, respectively) and a significant decrease in reflected wave traveling times (P=0.0007 vs. placebo). Aspirin 100 mg/day produced a similar, though non-significant, trend in these parameters compared with placebo. Both aspirin treatments produced a statistically significant decrease in serum TxB2 (P<0.0001) but did not have an effect on the metabolite of prostaglandin I2 (P=0.136).

CONCLUSION

This study demonstrates the existence of a dose-mediated deleterious effect of aspirin upon arterial functional properties in CHF patients treated with ACEI.

Antagonism of the acute hemodynamic effects of captopril in decompensated congestive heart failure by aspirin administration

The concomitant use of angiotensin-converting enzyme inhibitors and aspirin may cause pharmacological antagonism. Hence we examined the effect of aspirin on the neurohormonal function and hemodynamic response to captopril in heart failure patients. Between April 1999 and August 2000, 40 patients were randomized into four equal groups: 1) captopril, 2) aspirin, 3) captopril-aspirin: captopril was given alone on the first day, followed by aspirin on the remaining days, and 4) aspirin-captopril: aspirin was given alone on the first day, followed by captopril on the remaining days. Hemodynamic, norepinephrine and prostaglandin measurements were performed pre- and post-medication for 4 days. Captopril (50 mg) was given orally every 8 h and 300 mg aspirin was given on the first day, and 100 mg/day thereafter. In the captopril group and only on the first day of captopril-aspirin, captopril produced increases in cardiac index (2.1 +/- 0.6 to 2.5 +/- 0.5 l min-1 m-2, P<0.0001), and reduced peripheral vascular resistance (1980 +/- 580 to 1545 +/- 506 dyn s-1 cm-5/m , P<0.0001) and pulmonary wedge pressure (20 +/- 4 to 15 +/- 4 mmHg, P<0.0001). In contrast, aspirin alone or associated with captopril showed no significant hemodynamic changes. Norepinephrine decreased (P<0.02) only in the captopril group. Prostaglandin levels did not differ significantly among groups. Thus, aspirin compromises the short-term hemodynamic and neurohormonal effects of captopril in patients with acute decompensated heart failure.

Antiplatelet effects of angiotensin-converting enzyme inhibitors compared with aspirin and clopidogrel: a pilot study with whole-blood aggregometry

BACKGROUND

Although specific antiplatelet drugs are well-established and effective in atherosclerosis prevention, recent clinical trials have also shown that use of angiotensin-converting enzyme (ACE) inhibitors results in a decrease in cardiovascular events. Therefore, in this study, we sought to assess the coagulative activity of patients with cardiovascular disease grouped for treatment with either ACE inhibitors, aspirin, clopidogrel/aspirin, or none of these medications.

METHODS

Blood samples from 303 patients with cardiovascular disease were analyzed with whole-blood aggregometry. Platelet aggregation was determined by the increase in impedance across paired electrodes in response to the aggregatory agents adenosine diphosphate (ADP) or collagen.

RESULTS

As the central finding, platelet aggregation was attenuated by ACE inhibitors and by aspirin or clopidogrel/aspirin, which was indicated by a lower impedance increase compared with no medication. With ACE inhibition, platelet aggregation decreased by 33% (P =.042) after ADP induction. No significant antithrombotic effect was seen with aspirin alone (17%, P = 1.0), whereas a decrease in ADP-induced platelet aggregation was extensive with clopidogrel/aspirin (85%, P =.001). After collagen induction, platelet aggregation was reduced by 16% (P =.028) in the presence of ACE inhibitor therapy, whereas inhibition with aspirin and clopidogrel/aspirin was 23% (P =.004) and 35% (P =.026), respectively, compared with participants who were not treated.

CONCLUSIONS

These ex vivo data on whole-blood aggregometry provide direct evidence that ACE inhibitors decrease platelet aggregation, whereas aspirin and clopidogrel are confirmed as established antithrombotics. Pleiotropic effects of ACE inhibition on platelet function may contribute to the clinical benefit observed with this drug class on major cardiovascular end points.

Risks versus Benefits of NSAIDs Including Aspirin in Myocarditis

NSAIDs, including aspirin (acetylsalicylic acid), are frequently used and effective in a broad variety of inflammatory diseases, i.e. rheumatic carditis and pericarditis. Myocarditis may constitute another suitable indication for NSAIDs in order to relieve the symptoms of the presumed viral infection or because pericardial effusion is often associated with this condition. However, concerns have been raised about their indiscriminate use in myocarditis. To clarify this issue, we conducted a systematic review of the literature concerning myocarditis, aspirin and NSAIDs. We examined five animal studies of NSAIDs (indomethacin and ibuprofen) and aspirin in coxsackievirus B3- and B4-induced myocarditis. These studies indicated a deleterious effect of NSAIDs and aspirin in this setting, demonstrating a 2- to 3-fold increase in inflammation, myocytes necrosis and even mortality when compared with placebo. This possible deleterious effect was more predominant when NSAIDs or aspirin were administered during the acute and subacute phases of myocarditis; however, it was still noted when NSAIDs were administered during the late phase of the disease (the effect of aspirin was not evaluated in late phase studies). According to these animal studies, such effect might be attributed to decreased viral clearance (possibly via interferon inhibition) and/or exaggerated cytotoxic response (via interleukin-2 or inhibition of suppressor cells factors) and/or coronary artery spasm. We found one animal study looking at autoimmune myocarditis and it did not demonstrate any beneficial or detrimental effect of aspirin. Moreover, recent data suggest that aspirin and NSAIDs may counteract part of the efficacy of ACE inhibitors and be deleterious in chronic heart failure. Taken together, these studies point to a possible deleterious effect of aspirin and NSAIDs in human myocarditis. In view of these animal studies and in the absence of controlled studies of aspirin or NSAIDs in human myocarditis, we do not recommend indiscriminate treatment with NSAIDs or high-dose aspirin in patients with myocarditis where there is no or minimal associated pericarditis.

Effects of long-term treatment with angiotensin-converting-enzyme inhibitors in the presence or absence of aspirin: a systematic review

BACKGROUND

Results from a retrospective analysis of the Studies of Left Ventricular Dysfunction (SOLVD) study suggest that angiotensin-converting-enzyme (ACE) inhibitors may be less effective in patients receiving aspirin. We aimed to confirm or refute this theory.

METHODS

We used the Peto-Yusuf method to undertake a systematic overview of data for 22060 patients from six long-term randomised trials of ACE inhibitors to assess whether aspirin altered the effects of ACE inhibitor therapy on major clinical outcomes (composite of death, myocardial infarction, stroke, hospital admission for congestive heart failure, or revascularisation).

FINDINGS

Baseline characteristics, and prognosis in patients allocated placebo, differed strikingly between those who were and were not taking aspirin at baseline. Results from analyses of all trials, except SOLVD, did not suggest any significant differences between the proportional reductions in risk with ACE inhibitor therapy in the presence or absence of aspirin for the major clinical outcomes (p=0.15), or in any of its individual components, except myocardial infarction (interaction p=0.01). Overall, ACE inhibitor therapy significantly reduced the risk of the major clinical outcomes by 22% (p<0.0001), with clear reductions in risk both among those receiving aspirin at baseline (odds ratio 0.80, [99% CI 0.73-0.88]) and those who were not (0.71 [99% CI 0.62-0.81], interaction p=0.07).

INTERPRETATION

Considering the totality of evidence on all major vascular outcomes in these trials, there is only weak evidence of any reduction in the benefit of ACE-inhibitor therapy when added to aspirin. However, there is definite evidence of clinically important benefits with respect to these major clinical outcomes with ACE-inhibitor therapy, irrespective of whether concomitant aspirin is used.

Interaction between aspirin and angiotensin-converting enzyme inhibitors: should they be used together in older adults with heart failure?

PURPOSE

To determine whether the prostacyclin-inhibiting properties of aspirin counteracts the bradykinin-induced prostacyclin-stimulating effects of angiotensin-converting enzyme (ACE) inhibitors, thereby attenuating the beneficial effects of ACE inhibitors in heart failure patients.

BACKGROUND

Most heart failure patients are older adults. Heart failure is the number one hospital discharge diagnosis of older Americans. The renin-angiotensin system plays a major role in the pathophysiology of heart failure, and ACE inhibitors play a pivotal role in the management of heart failure. Large-scale double-blind randomized trials have demonstrated the survival benefits of using ACE inhibitors in patients with heart failure associated with left ventricular systolic dysfunction. In addition to inhibiting the conversion of angiotensin I to angiotensin II, ACE inhibitors also decrease the breakdown of bradykinin. Bradykinin, a potent vasodilator, acts by stimulating formation of vasodilatory prostaglandins such as prostacyclin, whereas aspirin or acetyl salicylic acid inhibits the enzyme cyclooxygenase, which in turn decreases the production of the prostaglandins. Coronary artery disease and hypertension are the two major underlying causes of heart failure. Most heart failure patients are also on aspirin. There is evidence that aspirin at a daily dose of 80 to 100 mg prevents the synthesis of thromboxane A2 by platelets while relatively sparing the synthesis of prostacyclin in the vascular endothelium. Aspirin at a daily dose of 325 mg has significant inhibitory effects on the vasodilatory prostacyclin synthesis. Studies have demonstrated that, in heart failure patients, low-dose aspirin has no adverse effect on hemodynamic, neurohumoral, or renal functions. Whether the prostacyclin-inhibiting effects of aspirin attenuate some of the beneficial effects of ACE inhibitors mediated by prostacyclin stimulation in heart failure patients is currently unknown.

METHODS

Data from large clinical trials investigating the interaction between aspirin and ACE inhibitors were analyzed to determine the effect of aspirin on the vasodilatory actions of ACE inhibitors in heart failure patients, and the results were analyzed on the basis of theoretical and laboratory findings. The studies included are the Studies of Left Ventricular Dysfunction (SOLVD) (N=6,797), the Cooperative New Scandinavian Enalapril Survival Study II (CONSENSUS II) (N=6,090), the Captopril and Thrombolysis Study (CATS) (N=296), and another study involving 317 subjects. The data from these clinical trials investigating the interaction between aspirin and ACE inhibitors included 13,470 subjects. Most of the subjects received aspirin. In the SOLVD study, subjects received aspirin or dipyridamole. Subjects were followed up for an average of about 6 years.

RESULTS

In the SOLVD study, subjects were followed up for 41.1 months in the treatment trial and 37.4 months in the prevention trial. Patients who received aspirin or dipyridamole at baseline did not receive the survival benefits of enalapril, whereas patients who received enalapril did not receive the survival benefits of aspirin. In a rather small study of 317 subjects with left ventricular systolic dysfunction (ejection fraction <35%) who were followed up for a relatively longer period of time (5.7 years), the favorable long-term prognosis of patients receiving aspirin was independent of receipt of an ACE inhibitor. A retrospective subgroup analysis of data from the CONSENSUS II study demonstrated that the 6-month mortality rate of patients with acute myocardial infarction (MI) who received enalapril and aspirin was higher than the combined mortality rates of patients receiving enalapril or aspirin alone. This strong interaction between aspirin and the ACE inhibitor enalapril suggests that the survival benefit of enalapril was significantly lower in patients also taking aspirin than in those taking enalapril alone. This interaction was not associated with other nonfatal major events. In the CATS study, use of low-dose aspirin (80 or 100 mg) did not attenuate beneficial effects of captopril (immediate and 1-year follow up) after acute MI.

CONCLUSION

There is a theoretical possibility that the negative interaction between ACE inhibitors and aspirin may reduce the beneficial effects of ACE inhibitors in patients with heart failure, but the information obtained from the existing databases is limited by the retrospective nature of the analyses and does not establish the association definitively. Double-blind randomized controlled trials should be conducted to determine whether such a negative interaction indeed exists.

Low-dose aspirin does not interfere with the blood pressure-lowering effects of antihypertensive therapy

BACKGROUND

It has been reported that aspirin (ASA) may interfere with the blood pressure (BP)-lowering effect of various antihypertensive agents and attenuate the beneficial effects of angiotensin-converting enzyme (ACE) inhibitors in patients with congestive heart failure.

METHODS AND RESULTS

Data from the Hypertension Optimal Treatment (HOT) Study, in which 18 790 intensively treated hypertensive patients were randomized to either ASA 75 mg daily or placebo for 3.8 years (with a 15% reduction in cardiovascular events and a 36% reduction in myocardial infarction in ASA-treated patients), were reanalysed for the whole group of patients and for various subgroups with particular attention to the possible effects of ASA on BP and renal function. In ASA-treated and placebo-treated patients: (1) systolic blood pressure (SBP) and diastolic blood pressure (DBP) values achieved with antihypertensive treatment were superimposable, with clinically irrelevant differences; (2) these superimposable SBP and DBP were achieved with antihypertensive therapies, that were quantitatively and qualitatively similar, and (3) changes in serum creatinine and in estimated creatinine clearance and the number of patients developing renal dysfunction were also similar. Furthermore, the cardiovascular benefits of ASA were of the same magnitude in hypertensive patients receiving or not receiving ACE-inhibitors.

CONCLUSIONS

Even long-term, low-dose ASA does not interfere with the BP-lowering effect of antihypertensive agents, including combinations with ACE inhibitors, or with renal function. No negative interaction occurs between ACE inhibition and the cardiovascular benefits of small dose of ASA. Our conclusions cannot be extended to larger doses of ASA, or to patients with congestive heart failure.

Is aspirin "the weakest link" in cardiovascular prophylaxis? The surprising lack of evidence supporting the use of aspirin for cardiovascular disease

It is currently fashionable to prescribe aspirin, long-term to people with or at high risk of vascular events due to atherosclerosis. There is a moderately conclusive evidence for a short-term benefit after an acute vascular event. However, there is remarkably little evidence that long-term aspirin is effective for the prevention of vascular events and managing side effects may be expensive. Reductions in nonfatal vascular events may reflect an ability of aspirin to alter cosmetically the presentation of disease without exerting real benefit. Cardiovascular medicine appears prone to fads and fashions that are poorly substantiated by evidence. The current fashion for prescribing aspirin is reminiscent of the now discredited practice of widespread prescription of class I anti-arrhythmic drugs for ventricular ectopics. We should learn from experience.

Combined aspirin/ACE inhibitor treatment for CHF

OBJECTIVE

To review the literature evaluating the interaction between angiotensin-converting enzyme (ACE) inhibitors and aspirin in patients with congestive heart failure (CHF).

DATA SOURCES

A literature search through MEDLINE (1966-March 2001) and EMBASE (1966-March 2001) identified randomized, double-blind, controlled trials evaluating the use of ACE inhibitors and aspirin in patients with CHF.

DATA SYNTHESIS

No prospective study has evaluated the effects of aspirin and ACE inhibitors on clinical outcomes of patients with CHF. All have been short-term studies evaluating the effects on hemodynamic parameters only.

CONCLUSIONS

While the potential for an interaction between ACE inhibitors and aspirin exists, the results from ongoing prospective trials will help determine the efficacy of using both agents in patients with CHF.

Aspirin impairs reverse myocardial remodeling in patients with heart failure treated with beta-blockers

OBJECTIVES

We hypothesized that aspirin (ASA) might alter the beneficial effect of beta-blockers on left ventricular ejection fraction (LVEF) in patients with chronic heart failure.

BACKGROUND

Aspirin blunts the vasodilation caused by both angiotensin-converting enzyme (ACE) inhibitors and beta-blockers in hypertensive patients and in patients with heart failure. Several studies suggest that ASA also blunts some of beneficial effects of ACE inhibitors on mortality in patients with heart failure. To our knowledge, there have been no data evaluating the possible interaction of ASA and beta-blockers on left ventricular remodeling in patients with heart failure.

METHODS

We retrospectively evaluated patients entered into the Multicenter Oral Carvedilol Heart failure Assessment (MOCHA) trial, a 6-month, double-blind, randomized, placebo-controlled, multicenter, dose-response evaluation of carvedilol in patients with chronic stable symptomatic heart failure. Multivariate analysis was performed to determine if aspirin independently influenced the improvement in LVEF.

RESULTS

Over all randomized patients (n = 293), LVEF improved 8.2 +/- 0.8 ejection fraction (EF) units in ASA nonusers and 4.5 +/- 0.7 EF units in ASA users (p = 0.005). In subjects randomized to treatment with carvedilol (n = 231), LVEF improved 9.5 +/- 0.9 EF units in ASA nonusers and 5.8 +/- 0.8 EF units in ASA users (p = 0.02). In subjects randomized to treatment with placebo (n = 62), LVEF improved 2.8 +/- 1.2 EF units in ASA nonusers and 0.5 +/- 1.4 EF units in ASA users (p = 0.20). Aspirin did not significantly affect the heart rate or systolic blood pressure response in either the placebo or carvedilol groups. The effect of ASA became more significant on multivariate analysis. The change in LVEF was also influenced by carvedilol dose, etiology of heart failure, baseline heart rate, EF and coumadin use. The detrimental effect of ASA on the improvement in LVEF was dose-related and was present in both placebo and carvedilol groups, although the effect was statistically significant only in the much larger carvedilol group.

CONCLUSIONS

Aspirin significantly affects the changes in LVEF over time in patients with heart failure and systolic dysfunction treated with carvedilol. The specific mechanism(s) underlying this interaction are unknown and further studies are needed to provide additional understanding of the molecular basis of factors influencing reverse remodeling in patients with heart failure.

To anticoagulate or not to anticoagulate patients with cardiomyopathy

The current published literature does not indicate whether the long-term effect of anticoagulant or antiplatelet therapy contributes to mortality reduction in patients with LV dysfunction. Evaluating patients for personal risk for emboli or for ischemic coronary artery events may influence the choice of therapies. As more is learned about the mechanisms of drug effects in different populations, physicians may be better able to direct appropriate therapies. Until that time, one must weigh the risks and benefits of each drug alone and in combination. In NYHA class IV patients, the risk for thrombosis owing to spontaneous clotting increases as does the adverse potential of warfarin and the adverse effects of inhibiting prostaglandin mediated vasodilation by aspirin. In NYHA class I and II patients, the quality of life and convenience of multidrug therapy is weighed against the devastating effect of a major stroke. In less symptomatic patients, the long-term risk for acute coronary events may be higher than previously identified. This would suggest that all patients with depressed LV function should be on some type of antiplatelet or anticoagulant therapy. The current WATCH study will provide much needed information about the outcome differences between these agents. Conclusions based on available data include the following: Heart failure is increasing in incidence and prevalence. Atherosclerotic disease is an important causative factor for the development of heart failure or may be a comorbid condition in these patients. There is a measurable rate of stroke in patients with heart failure, although the cause of death in large studies is more often owing to sudden death or progressive heart failure. Sudden death may be from new ischemic events, asystole, or from ventricular tachyarrhythmias. In patients with heart failure, not all strokes are cardioembolic in origin. The benefits and risks of warfarin may be increased as the EF worsens or heart failure functional class declines. The interactions of aspirin and ACE inhibitors have been best evaluated for the hemodynamic effects. There may be additional factors hitherto not studied. The hemodynamic effect of ACE inhibitors may be more important in NYHA classes III and IV than in less symptomatic patients. Warfarin use has clear indications for patients in atrial fibrillation with mechanical prosthetic valves, in hypercoagulable states, and with a previous history of embolization. Aspirin is inexpensive and commonly available, but its use must be evaluated and articulated by the prescribing physician. The current multicenter prospective trials will provide much needed guidance on this subject. The ongoing trials do not have a placebo arm, however, indicating a consensus among clinicians that patients with cardiomyopathy should be on an antiplatelet or anticoagulant drug until further data emerge.

Does aspirin attenuate the effect of angiotensin-converting enzyme inhibitors in hypertension or heart failure?

There is a wealth of data that suggests an important interaction between aspirin and angiotensin-converting enzyme inhibitors in patients with chronic stable cardiovascular disease. The interaction is less obvious in the postinfarction setting, possibly reflecting the fact that many patients stop their aspirin therapy within a few months of such an event. An interaction is biologically plausible, because there is considerable evidence that angiotensin-converting enzyme inhibitors exert important effects through increasing the production of vasodilator prostaglandins, whereas aspirin blocks their production through inhibition of cyclooxygenase, even at low doses. There is some evidence that low-dose aspirin may raise systolic and diastolic blood pressure. There is also considerable evidence that aspirin may entirely neutralize the clinical benefits of angiotensin-converting enzyme inhibitors in patients with heart failure. In addition, aspirin may have an adverse effect on outcome in patients with heart failure that is independent of any interaction with angiotensin-converting enzyme inhibitors, possibly by blocking endogenous vasodilator prostaglandin production and enhancing the vasoconstrictor potential of endothelin. The evidence is not sufficient to justify advising long-term aspirin therapy for patients with cardiovascular disease in general, and for those with heart failure in particular. Thus, the lack of evidence of benefit with aspirin in patients with heart failure and coronary disease, along with growing evidence that aspirin is directly harmful in patients with heart failure and that aspirin may negate the benefits of angiotensin-converting enzyme inhibitors suggest that, unless there is an opportunity to randomize the patient into a study of antithrombotic strategies, then aspirin should be withdrawn or possibly substituted with an anticoagulant or an antiplatelet agent that does not block cyclooxygenase. In contrast, there is fairly robust evidence for a benefit of both aspirin and angiotensin-converting enzyme inhibitors during the first 5 weeks after a myocardial infarction, with little evidence of an interaction. The combination of aspirin and angiotensin-converting enzyme inhibitors is warranted during this period, after which discontinuation or substitution of aspirin with another agent should be considered.

The angiotensin-converting enzyme inhibitor and aspirin interaction in congestive heart failure: fear or reality?

Angiotensin-converting enzyme (ACE) inhibitors have become the cornerstone of therapy for congestive heart failure (CHF). Because ischemic heart disease is the most common cause of CHF, aspirin is frequently given concomitantly with ACE inhibitors in patients with CHF. Increased bradykinin levels, with the consequent enhanced synthesis of vasodilatory prostaglandins, appear to mediate a significant benefit of ACE inhibitor therapy in these patients. In contrast, aspirin inhibits cyclooxygenase, and thereby suppresses prostaglandin production. Thus, these counteracting effects on prostaglandins may result in antagonism between ACE inhibitor and aspirin therapy in heart failure patients. Several early reports questioned the safety of aspirin in CHF, and the potential antagonistic interaction between ACE inhibitors and aspirin in patients with heart failure has become the focus of both increasing research and intense debate. This article briefly highlights the theoretic considerations underlying this interaction, and reviews the available evidence for such an interaction from clinical trials.

What is the optimal medical management of ischemic heart failure?

Ischemic heart disease is an important and common contributor to the development of heart failure. Theoretically, all patients with heart failure may benefit from treatment designed to retard progressive ventricular dysfunction and arrhythmias. Patients with ischemic heart disease may also theoretically benefit from the relief of ischemia, the prevention of coronary occlusion, and revascularization. However, there is little evidence to show that the presence or absence of coronary disease modifies the benefits of effective treatments such as angiotensin-converting enzyme inhibitors and beta-blockers. Moreover, there is no evidence that treatment directed specifically at myocardial ischemia or coronary disease alters outcome in patients with heart failure. Treatments aimed at relieving painless myocardial ischemia have not been shown to alter prognosis. Lipid-lowering therapy is theoretically attractive for patients with heart failure and coronary disease; however, theoretical concerns also exist about the safety of such agents, and patients with heart failure have been excluded from large outcome studies very effectively. Some agents, such as aspirin, designed to reduce the risk of coronary occlusion seem ineffective or harmful in patients with heart failure, although warfarin may be safe and possibly effective. There is no evidence yet that revascularization improves prognosis in patients with heart failure, even in patients who are shown to have extensive myocardial hibernation. On current evidence, revascularization should be reserved for the relief of angina. Large-scale, randomized controlled trials are currently underway that are investigating the role of specific treatments targeted at coronary syndromes. The Carvedilol Hibernation Reversible Ischemia Trial: Marker of Success study is investigating the effects of carvedilol in a large cohort of patients with and without hibernating myocardium. The Warfarin and Antiplatelet Therapy in Chronic Heart Failure study is comparing the efficacy of aspirin, clopidogrel, and warfarin. The Heart Revascularization Trial-United Kingdom study is assessing the effect of revascularization on mortality in patients with heart failure and myocardial hibernation. Smaller scale studies are assessing the safety and efficacy of statin therapy in patients with heart failure. Only once the outcomes to these and other planned trials are known can the medical community know how best to treat their patients.

Effect of combined aspirin and angiotensin-converting enzyme inhibitor therapy versus angiotensin-converting enzyme inhibitor therapy alone on readmission rates in heart failure

An adverse interaction between aspirin and angiotensin-converting enzyme (ACE) inhibitors is suspected in patients with heart failure, but the effect of combined therapy with these agents on hospital readmission rates is unknown. Our study found that combining aspirin with ACE inhibitors is associated with higher early readmission rates than use of ACE inhibitors alone, particularly in patients with depressed ejection fraction and in those without coronary artery disease.

Interaction between Aspirin and ACE Inhibitors in Patients with Heart Failure

Both aspirin (acetylsalicylic acid) and ACE inhibitors are often used concomitantly, especially in patients with both heart failure and ischaemic heart disease, which is the most common underlying cause of heart failure. The safety of the association has been questioned because both drugs affect a related prostaglandin-mediated pathway. Thanks to their vasodilating properties, prostaglandins play an important role in heart failure where peripheral vasoconstriction occurs. Some of the beneficial effects of ACE inhibitors might be related to reduced degradation of bradykinin that enhances the synthesis of prostaglandins, while aspirin, through inhibiting the enzyme cyclo-oxygenase, inhibits the production of prostaglandins. To date no prospective study has been conducted to investigate the effect of long term aspirin treatment in the postinfarction period allowing the possible impact of the interaction between aspirin and ACE inhibitors upon survival to be confirmed or negated. However, the practitioner needs to know how to optimise the treatment of his or her patients. In order to stimulate arguments for and against the use of aspirin in patients with heart failure receiving ACE inhibitors, we searched MEDLINE from 1960 to 2000 using the key words heart failure, aspirin, and ACE inhibitors for English language articles and conducted a review of the available data. We report on the potential mechanisms of the interaction and the results of experimental studies on haemodynamic parameters. Results of retrospective clinical studies, subgroup analysis that were undertaken to evaluate the overall action upon haemodynamic parameters and survival of the association are summarised. Conflicting conclusions have been reported in the literature. Many explanations can be advanced to try to understand these conflicting conclusions: differences in study design (results of retrospective trials have to be interpreted with caution); differences in the choice of the evaluation parameter (problem of the clinical relevance of haemodynamic parameters); differences in the characteristics of the patient (different underlying cardiopathy, e.g. heart failure, hypertension or ischaemic cardiopathy); and differences in the type and the dosage of each treatment (especially ACE inhibitors and aspirin since an interaction might occur more often with dosage of aspirin greater than 250mg).

What is the optimal medical management of ischaemic heart failure?

Ischaemic heart disease is probably the most important cause of heart failure. All patients with heart failure may benefit from treatment designed to retard progressive ventricular dysfunction and arrhythmias. Patients with heart failure due to ischaemic heart disease may also, theoretically, benefit from treatments designed to relieve ischaemia and prevent coronary occlusion and from revascularisation. However, there is little evidence to show that effective treatments, such as angiotensin converting enzyme (ACE) inhibitors and beta-blockers, exert different effects in patients with heart failure with or without coronary disease. Moreover, there is no evidence that treatment directed specifically at myocardial ischaemia, whether or not symptomatic, or coronary disease alters outcome in patients with heart failure. Some agents, such as aspirin, designed to reduce the risk of coronary occlusion appear ineffective or harmful in patients with heart failure. There is no evidence, yet, that revascularisation improves prognosis in patients with heart failure, even in patients who are demonstrated to have extensive myocardial hibernation. On current evidence, revascularisation should be reserved for the relief of angina. Large-scale, randomised controlled trials are currently underway investigating the role of specific treatments targeted at coronary syndromes in patients who have heart failure. The CHRISTMAS study is investigating the effects of carvedilol in a large cohort of patients with and without hibernating myocardium. The WATCH study is comparing the efficacy of aspirin, clopidogrel and warfarin. The HEART-UK study is assessing the effect of revascularisation on mortality in patients with heart failure and myocardial hibernation. Smaller scale studies are currently assessing the safety and efficacy of statin therapy in patients with heart failure. Only when the results of these and other studies are known will it be possible to come to firm conclusions about whether patients with heart failure and coronary disease should be treated differently from other patients with heart failure due to left ventricular systolic dysfunction.

Anticoagulation and heart failure

There are no clear data regarding whether to use warfarin, aspirin, or no therapy in patients with left ventricular systolic dysfunction. Aspirin use is widespread in patients with vascular disease but it can decrease renal blood flow in low output states. Warfarin may be used in patients with advancing heart failure due to the perceived risk of in situ thromboembolism. However, we know that ejection fraction and symptom class do not always match and that the regulation of warfarin dosing is more difficult in worsening heart failure. Drug use must be individualized, based on knowledge of underlying heart failure etiology, functional class, drug side effects, and renal function. We await ongoing studies to elucidate the differential effects of these drugs on global outcome as well as on the mechanisms by which they achieve their results.