Antiplatelet and anticoagulant therapy in the prevention of thromboemboli in chronic heart failure

Relation of Acute Decompensated Heart Failure to Silent Cerebral Infarcts in Patients With Reduced Left Ventricular Ejection Fraction

Heart failure (HF) is a prothrombotic state with increased rate of thromboembolic events. Magnetic resonance imaging studies demonstrated increased rate of silent cerebral infarcts (SCI) in this patient group and SCIs were shown lead to dementia, cognitive decline, and depression. We aimed to show acute decompensated phase is associated with increased rate of recent SCI in reduced ejection fraction HF patients. HF patients with sinus rhythm hospitalized for acute decompensation were studied. Neuron specific enolase (NSE), a sensitive neuronal ischemia marker, was used to detect recent SCI. Decompensated and compensated phase blood samples for NSE were collected on the day of admission and on the third day of compensation, respectively. One hundred and forty seven patients with mean age of 72 were studied. There were significantly more patients with positive NSE levels at decompensated state (29% vs 4%, p <0.001). Multivariate predictors for recent SCI were smoking, new onset atrial fibrillation, spontaneous echo contrast of left ventricle, and aneurysmatic apex. Statin use was found to be protective against NSE elevation. In conclusion, our data reveal that decompensated HF is significantly associated with increased levels of NSE suggestive for silent neuronal injury.

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.

Effects of clopidogrel and aspirin combination versus aspirin alone on platelet aggregation and major receptor expression in patients with heart failure: the Plavix Use for Treatment Of Congestive Heart Failure (PLUTO-CHF) trial

BACKGROUND

Persistent platelet activation may contribute to thrombotic events in patients with congestive heart failure (CHF). Chronic use of mild platelet inhibitors could therefore represent an independent avenue to improve morbidity, mortality, and quality of life in this expanding population. Although clopidogrel is widely used in patients with acute coronary syndromes and ischemic stroke, the ability of this novel ADP-receptor antagonist to inhibit platelet function in patients with CHF is unknown. We assessed antiplatelet properties of clopidogrel with aspirin (C+A) versus aspirin alone (A) in patients with CHF with heightened platelet activity.

METHODS

Patients with left ventricular ejection fraction <40%, or CHF symptoms in the setting of preserved systolic function and New York Heart Association class II-IV were screened. Patients were considered to have platelet activation when 4 of the following 5 parameters were met: ADP-induced platelet aggregation >60%; collagen-induced aggregation >70%; whole blood aggregation >18 ohms; expression of GP IIb/IIIa >220 log MFI; and P-selectin cell positivity >8%. All patients were treated with 325 mg of acetylsalycilic acid (ASA) for at least 1 month. Patients receiving an antithrombotic agent other than ASA were excluded. Patients meeting clinical and laboratory criteria were randomly assigned to C+A (n=25), A (n=25) groups, or represent screen failures (n=38). Platelet studies (conventional and whole blood aggregometry, shear-induced activation, expression of 10 major receptors and formation of platelet-leukocyte microparticles) were performed at baseline and after 30 days of therapy.

RESULTS

There were no deaths, hospitalizations, or serious adverse events. There were no changes in platelet parameters in the A group. In contrast, therapy with C+A resulted in a significant inhibition of platelet activity assessed by ADP-induced (P =.00001), and epinephrine-induced (P =.0016) aggregation, closure time (P =.04), expression of PECAM-1 (P =.009), GP Ib (P =.006), GP IIb/IIIa antigen (P =.0001), GP IIb/IIIa activity with PAC-1 (P =.0021), and CD151 (P =.0026) when compared with the A group. Therapy with C+A also resulted in the reduced formation of platelet-leukocyte microparticles (P =.021). Collagen-induced aggregation in plasma and in whole blood, expression of vitronectin receptor, P-selectin, CD63, CD107a, and CD107b did not differ among groups.

CONCLUSIONS

Treatment with C+A for 1 month provides significantly greater inhibition of platelet activity than ASA alone in patients with CHF. Patients with CHF with heightened platelet activity represent a potential target population in which addition of clopidogrel may decrease mortality rates by reducing the incidence of thrombotic vascular events.

Thromboembolism in heart failure: who should be treated?

The risk of thromboembolic complications in patients with heart failure and/or chronic left-ventricular systolic dysfunction is increased. Nevertheless, anticoagulant therapy in these patients is still a subject of debate. Atrial fibrillation is the only prospectively evaluated, proven thromboembolic risk factor and patients with atrial fibrillation benefit from long term anticoagulant therapy. The significance of other proposed thromboembolic risk factors in heart failure and/or chronic left-ventricular dysfunction such as gender, cause of myocardial disease, severity of heart failure, left-ventricular ejection fraction, left-ventricular thrombus, left ventricular aneurysm and history of previous thromboembolic event is less clear. This article summarizes key studies, assesses the incidence of thromboembolism, evaluates risk factors and proposes guidelines for anticoagulation of patients with heart failure and/or left ventricular systolic dysfunction.

Idiopathic Cardiomyopathy

Idiopathic cardiomyopathy is a very common cause of heart failure today. It is a diagnosis of exclusion, and careful attention should be paid to the patient history to exclude all other causes. ACE inhibitors have become the first line therapy for all classes of left ventricular dysfunction. Doses of all therapeutic drugs for CHF should be up-titrated to maximum targeted dosages. New agents are being developed that offer increasing hope for therapies that will alter the natural history of heart failure.

Hemostatic abnormalities in patients with congestive heart failure: diagnostic significance and clinical challenge

Knowledge of the pathogenesis of congestive heart failure (CHF) has improved greatly in recent years. However, this disease continues to cause one of the highest morbidities and mortalities in the Western world. The pathophysiology of heart failure is complex and much of our understanding revolves strictly around the neurohormonal mechanisms involved. Various pharmacologic interventions have significantly improved morbidity and include ACE inhibitors, beta-blockers, diuretics, and inotropic agents. Yet, no consensus has been reached regarding the use of anticoagulants or antiplatelet agents. It has been suggested that CHF is associated with altered hemostasis, but whether this prothrombotic state contributes to the pathogenesis and progression of the disease is unknown. The purpose of this review article is to discuss our current knowledge of platelet activation, thrombin generation, fibrinolysis, and endothelial dysfunction in CHF patients, and the potential role of anticoagulants and/or antiplatelet agents in preventing these hemostatic abnormalities.