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

Possible interaction between aspirin and ACE inhibitors: update on unresolved controversy

The widespread use of aspirin and angiotensin converting enzyme (ACE) inhibitors in patients with coronary artery disease contributes significantly to the reduction in morbidity and mortality from this common health problem. These agents are widely and concomitantly used, and they share mechanisms that may interact in negative or positive pathways. Data derived from in vitro preparations, animal studies, human studies, and case-control studies are inconsistent. No study has established firm evidence regarding the safety or adverse effect of aspirin on patients who are on ACE inhibitors. The efficacy and safety of aspirin in combination with ACE inhibitors has been questioned and debated. If a negative interaction does exist, it will affect daily practice in treating patients with coronary artery disease and heart failure. This article reviews the available data regarding the safety of combined aspirin and ACE-inhibitor treatment among patients with ischemic heart disease, to assess the possible interaction between the two drugs and to discuss the significance and implications of the data. (c)2000 by CHF, Inc.

Evaluation of the effects of aspirin combined with angiotensin-converting enzyme inhibitors in patients with coronary artery disease

BACKGROUND

Several studies have suggested that there may be an interaction between angiotensin-converting enzyme (ACE) inhibitors and aspirin in patients with congestive heart failure, such that their benefits are attenuated when used in combination. Whether this interaction exists in patients with coronary artery disease is not known.

SUBJECTS AND METHODS

Patients enrolled in two large trials, Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) and Evaluation in PTCA to Improve Long-Term Outcome with Abciximab GP IIb/IIIa Blockade (EPILOG), were stratified according to use of aspirin and ACE inhibitors on discharge from the hospital. In the EPILOG trial, left ventricular systolic function was assessed by contrast ventriculography. The primary endpoint was all-cause mortality at 1 year. EPILOG patients, all of whom were receiving aspirin, were also examined for the combined endpoint of death or nonfatal myocardial infarction. Stratified and multivariate analyses were used to adjust for baseline differences in patient characteristics.

RESULTS

We studied 31,622 patients in the GUSTO-I trial and 2,619 patients in the EPILOG trial. There were 615 deaths among the GUSTO-I patients and 45 deaths among the EPILOG patients at 1 year. Unadjusted mortality was greater among patients treated with both ACE inhibitors and aspirin than among patients treated with aspirin alone (3.3% versus 1.6%, P <0.001 for GUSTO-I; and 3.7% versus 1.2%, P <0.001 for EPILOG). Similarly, the composite endpoint of death or nonfatal myocardial infarction was more frequent among EPILOG patients who were taking ACE inhibitors (6.3% versus 3.3%, P = 0. 001). After adjusting for confounders, combined use of aspirin and ACE inhibitors was associated with increased mortality in GUSTO-I patients (hazard ratio [HR] = 2.2, 95% confidence interval [CI]: 1.1 to 4.3, P = 0.03) compared with aspirin alone. In EPILOG patients, after adjusting for clinical factors and extent of left ventricular dysfunction, the combination of aspirin and ACE inhibitors was associated with an increased risk of death (HR = 2.1, 95% CI: 1.1 to 3.8, P = 0.02) and of death or nonfatal myocardial infarction (HR = 1.5, 95% CI: 1.1 to 2.5, P = 0.02) compared with aspirin alone.

CONCLUSION

These observational findings suggest the possibility of an interaction between aspirin and ACE inhibitors among patients with ischemic heart disease. Further study of this issue is warranted.

Antiplatelet agents in cardiology: the choice of therapy

BACKGROUND

The platelet-rich, intracoronary thrombus is central to the pathogenesis of acute myocardial infarctions, unstable angina, and the majority of complications of percutaneous coronary interventions. Until recently, aspirin was the only antiplatelet agent available to help prevent or treat these events. Over the past several years, there has been a substantial expansion in our antiplatelet armamentarium as well as in our understanding of the clinical importance of antiplatelet therapy in limiting the complications of intracoronary thrombosis. Because of this, it is likely that over the coming years, the use of antiplatelet therapies will continue to expand, and it may not be unusual for a surgeon to encounter a patient being treated with two or even three platelet inhibitors.

CONCLUSIONS

This review will highlight the benefits and limitations of the currently available antiplatelet regimens: aspirin, thienopyridines (ticlopidine and clopidogrel), and the platelet glycoprotein IIb/IIIa inhibitors.

Reduction in the need for hospitalization for recurrent ischemic events and bleeding with clopidogrel instead of aspirin. CAPRIE investigators

BACKGROUND

Repeat hospitalizations of patients with atherosclerosis represent a considerable burden on the health care system. We sought to determine whether clopidogrel compared with aspirin decreases the need for rehospitalization for ischemia and bleeding.

METHODS AND RESULTS

The Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) trial was a randomized, blinded, multicenter, trial of 19,185 patients with atherosclerotic disease manifested as recent ischemic stroke or myocardial infarction or symptomatic peripheral arterial disease. Without any double-counting of events, the number of rehospitalizations for ischemic events (defined as angina, transient ischemic attack, or limb ischemia) or bleeding events was determined for the entire cohort. There was a significant reduction in the total number of rehospitalizations for ischemic events or bleeding with clopidogrel use compared with aspirin (1502 vs 1673; P =.010) over an average of 1.6 years of treatment. This reduction in rehospitalization was consistent across individual outcomes of angina, transient ischemic attack, limb ischemia, and bleeding. Compared with aspirin, clopidogrel also resulted in a 7.9% relative risk reduction in a combined end point of vascular death, stroke, myocardial infarction, or rehospitalization for ischemic events or bleeding (15.1% to 13.7% at 1 year; P =.011). Adjusting for baseline prognostic variables, clopidogrel therapy was an independent predictor for reduction of vascular death, stroke, myocardial infarction, or rehospitalization for ischemic events or bleeding (P =.009).

CONCLUSIONS

Treatment with clopidogrel results in a significant decrease in the need for rehospitalization for ischemic events or bleeding compared with aspirin. This meaningful end point tracks well with other, more traditional measures of outcome and has incremental value beyond such end points.

Update on the interaction between aspirin and angiotensin-converting enzyme inhibitors

We summarized recent published literature regarding the significance of an interaction between aspirin and angiotensin-converting enzyme (ACE) inhibitors in patients with various cardiovascular diseases. A MEDLINE search (January 1998-July 1999) was performed and abstracts from the 1999 American College of Cardiology and 1998 American Heart Association annual scientific sessions were reviewed to identify pertinent studies. Material for discussion was identified through a MEDLINE search from January 1996-July 1999 and through cited references. The results of several studies added to our understanding of the clinical ramifications of an aspirin-ACE inhibitor interaction, but also introduced questions. These studies are largely contradictory, but do reiterate the possibility of an interaction, if only in certain subsets of patients. Low dosages (< or = 100 mg/day) of aspirin appear to be safer in this regard than higher dosages. The frequency and severity of the interaction and possible predisposing factors await future research.

Clinical effects of early angiotensin-converting enzyme inhibitor treatment for acute myocardial infarction are similar in the presence and absence of aspirin: systematic overview of individual data from 96,712 randomized patients. Angiotensin-converting Enzyme Inhibitor Myocardial Infarction Collaborative Group

OBJECTIVES

We sought to determine whether the clinical effects of early angiotensin-converting enzyme (ACE) inhibitor (ACEi) treatment for acute myocardial infarction (MI) are influenced by the concomitant use of aspirin (ASA).

BACKGROUND

Aspirin and ACEi both reduce mortality when given early after MI. Aspirin inhibits the synthesis of vasodilating prostaglandins, and, in principle, this inhibition might antagonize some of the effects of ACEi. But it is uncertain whether, in practice, this influences the effects of ACEi on mortality and major morbidity after MI.

METHODS

This overview sought individual patient data from all trials involving more than 1,000 patients randomly allocated to receive ACEi or control starting in the acute phase of MI (0-36 h from onset) and continuing for four to six weeks. Data on concomitant ASA use were available for 96,712 of 98,496 patients in four eligible trials (and for none of 1,556 patients in the one other eligible trial).

RESULTS

Overall 30-day mortality was 7.1% among patients allocated to ACEi and 7.6% among those allocated to control, corresponding to a 7% (standard deviation [SD], 2%) proportional reduction (95% confidence interval 2% to 11%, p = 0.004). Angiotensin-converting enzyme inhibitor was associated with similar proportional reductions in 30-day mortality among the 86,484 patients who were taking ASA (6% [SD, 3%] reduction) and among the 10,228 patients who were not (10% [SD, 5%] reduction: chi-squared test of heterogeneity between these reductions = 0.4; p = 0.5). Angiotensin-converting enzyme inhibitor produced definite increases in the incidence of persistent hypotension (17.9% ACEi vs. 9.4% control) and of renal dysfunction (1.3% ACEi vs. 0.6% control), but there was no good evidence that these effects were different in the presence or absence of ASA (chi-squared for heterogeneity = 0.4 and 0.0, respectively; both not significant). Nor was there good evidence that the effects of ACEi on other clinical outcomes were changed by concomitant ASA use.

CONCLUSIONS

Both ASA and ACEi are beneficial in acute MI. The present results support the early use of ACEi in acute MI, irrespective of whether or not ASA is being given.

The impact of acute rejection on chronic rejection: a report of the North American Pediatric Renal Transplant Cooperative Study

The North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) group has analyzed its database from January 1987 to October 1998. During this time we enrolled 6,395 transplants: of these, 5,323 were primary and 1,072 were repeat transplants. Overall, 30.8% (483/1,566) of the grafts failed as a result of chronic rejection. For living donor (LD) grafts, the failure rate as a result of chronic rejection was 32% (175/553), and it was 30% (308/1,013) for cadaveric donor (CD) transplants. A proportional hazards model identified first acute rejection, multiple rejections, and a late acute rejection as risk factors for the development of chronic rejection. Additional risk factors for the development of chronic rejection were African-American race, a repeat transplant, and a cyclosporin A (CsA) dose of < 5 mg/kg/day. Our analysis found that one acute rejection episode increases the risk of chronic rejection graft failure three-fold. Patients with two or more acute rejections have a 12-fold increased relative risk (RR) of chronic rejection graft loss (CRGL). A late acute rejection (> 365 days post-transplant) increases the RR by six-fold. Two or more acute rejections, when the first is a late initial rejection, increases the RR 26-fold. Based on this information we have initiated a multicenter trial of intervention in patients with one or more acute rejections.

Optimising management of patients with advanced heart failure: the importance of preventing progression

Heart failure is a highly complex, progressive and deadly disease. When incorrectly treated, it results in irreversible structural damage to the myocardium and resists any conventional treatment. This stage has been arbitrarily termed refractory heart failure. However, with timely and sufficiently applied neurohumoral antagonists, progression can be prevented, or at least delayed. In contrast, as soon as heart failure has become moderate or severe due to advanced left ventricular dysfunction, polypharmacy is the rule. Physicians should make every effort to maintain or reconsider optimal neurohumoral antagonist therapy in such patients, even if symptomatic improvement from these agents may be slow. Proper use of diuretics is essential not only for symptom relief but also to achieve full benefit from angiotensin converting enzyme inhibitors and beta-blockers. Digitalis may be particularly indicated in severe heart failure, irrespective of rhythm. Adjunctive regimens can be helpful in specific patients, but evidence of their salutary effects to prolong life is lacking. In the decompensated state, tailoring intravenous therapy to haemodynamic goals followed by (re-)institution of optimal oral therapy is an option. Only if these strategies fail is heart transplantation justified. While waiting for a donor, patients have been bridged with various intravenous agents, most often inotropes, but symptom relief is associated with risk of increased mortality due to these drugs. New hope emerges from drugs interfering with endothelin and the cytokines, and from research into increasing contractility with calcium sensitising agents. Even though these developments follow established routes, they may enable a more effective approach to prevent worsening heart failure in every single patient.

Antiplatelet and anticoagulant therapy in the secondary prevention of ischemic heart disease

Antiplatelet and anticoagulant medications play a major role in the secondary prevention of ischemic heart disease. Numerous trials have demonstrated their clinical benefits. Newer agents, such as clopidogrel, have challenged aspirin's role as the premier medication for secondary prevention. Much remains to be learned, however, about the merits of these different drug classes, relative to one another and in combination.

Aspirin and mortality in patients treated with angiotensin-converting enzyme inhibitors: a cohort study of 11,575 patients with coronary artery disease

OBJECTIVES

The purpose of this study was to investigate the significance of the possible negative interaction between aspirin and angiotensin-converting enzyme (ACE) inhibitors.

BACKGROUND

Several provocative reports have recently suggested that aspirin is unsafe in patients with heart failure and has negative interaction with ACE inhibitors that might attenuate their beneficial effects upon survival.

METHODS

We analyzed mortality data of 11,575 patients with coronary artery disease screened for the Bezafibrate Infarction Prevention trial. A total of 1,247 patients (11%) were treated with ACE inhibitors. Of them, 618 patients (50%) used aspirin.

RESULTS

Five-year mortality was lower among patients on ACE inhibitors and aspirin than patients on ACE inhibitors without aspirin (19% vs. 27%; p < 0.001). After adjusting for confounders, treatment with aspirin and ACE inhibitors remained associated with lower mortality risk than using ACE inhibitors only (relative risk [RR] = 0.71; 95% confidence interval [CI] = 0.56 to 0.91). Subgroup analysis of 464 patients with congestive heart failure treated with ACE inhibitors revealed 221 patients (48%) on aspirin and 243 patients not on aspirin. Although clinical characteristics and therapy were similar, patients taking aspirin experienced lower mortality than patients who did not (24% vs. 34%; p = 0.001). After adjustment, treatment with aspirin was still associated with lower mortality (RR = 0.70; 95% CI = 0.49 to 0.99).

CONCLUSIONS

Among coronary artery disease patients with and without heart failure who are treated with ACE inhibitors, the use of aspirin was associated with lower mortality than treatment without aspirin. Our findings contradict the claim that aspirin attenuates the beneficial effect of ACE inhibitors and supports its use in patients with coronary artery disease treated with ACE inhibitors.