Aspirin as a therapeutic agent in cardiovascular disease. Special Writing Group

Antithrombotic strategies for preventing graft failure in coronary artery bypass graft

Coronary artery bypass graft (CABG) procedures face challenges related to graft failure, driven by factors such as acute thrombosis, neointimal hyperplasia, and atherosclerotic plaque formation. Despite extensive efforts over four decades, the optimal antithrombotic strategy to prevent graft occlusion while minimizing bleeding risks remains uncertain, relying heavily on expert opinions rather than definitive guidelines. To address this uncertainty, we conducted a review of randomized clinical trials and meta-analyses of antithrombotic therapy for patients with CABG. These studies examined various antithrombotic regimens in CABG such as single antiplatelet therapy (aspirin or P2Y12 inhibitors), dual antiplatelet therapy, and anticoagulation therapy. We evaluated outcomes including the patency of grafts, major adverse cardiovascular events, and bleeding complications and also explored future perspectives to enhance long-term outcomes for CABG patients. Early studies established aspirin as a key component of antithrombotic pharmacotherapy after CABG. Subsequent randomized controlled trials focused on adding a P2Y12 inhibitor (such as clopidogrel, ticagrelor, or prasugrel) to aspirin, yielding mixed results. This article aims to inform clinical decision-making and guide the selection of antithrombotic strategies after CABG.

The Role of Endothelial Cells in the Onset, Development and Modulation of Vein Graft Disease

Endothelial cells comprise the intimal layer of the vasculature, playing a crucial role in facilitating and regulating aspects such nutrient transport, vascular homeostasis, and inflammatory response. Given the importance of these cells in maintaining a healthy haemodynamic environment, dysfunction of the endothelium is central to a host of vascular diseases and is a key predictor of cardiovascular risk. Of note, endothelial dysfunction is believed to be a key driver for vein graft disease-a pathology in which vein grafts utilised in coronary artery bypass graft surgery develop intimal hyperplasia and accelerated atherosclerosis, resulting in poor long-term patency rates. Activation and denudation of the endothelium following surgical trauma and implantation of the graft encourage a host of immune, inflammatory, and cellular differentiation responses that risk driving the graft to failure. This review aims to provide an overview of the current working knowledge regarding the role of endothelial cells in the onset, development, and modulation of vein graft disease, as well as addressing current surgical and medical management approaches which aim to beneficially modulate endothelial function and improve patient outcomes.

Secondary prevention after coronary artery bypass graft surgery: a primer

PURPOSE OF REVIEW

Despite the benefits of surgical coronary revascularization, patients continue to be at risk for ischemic events in the years that follow coronary artery bypass graft surgery (CABG), mandating the role for postoperative secondary preventive therapy. The purpose of this review was to present a summary on the subject of secondary prevention after CABG, including an overview of a recently published scientific statement, and highlight the newest studies in the field.

RECENT FINDINGS

Aspirin and statin therapy continue to be the mainstay of secondary prevention after CABG, although newer antiplatelet and lipid-lowering medicines are being actively studied for their potential benefits. Other important elements to secondary prevention after CABG include the aggressive management of hypertension, smoking cessation, and the initiation of cardiac rehabilitation.

SUMMARY

Secondary prevention is an essential component of postoperative care after CABG. Instituting preventive therapies after surgery optimizes graft patency and helps patients achieve the highest level of physical health and quality of life following CABG.

Impact of ticagrelor versus aspirin on graft patency after CABG: Rationale and design of the TARGET (ticagrelor antiplatelet therapy to reduce graft events and thrombosis) randomized controlled trial (NCT02053909)

RATIONALE

Saphenous vein graft disease remains a major limitation of coronary artery bypass graft surgery (CABG). Up to 20% of vein grafts will occlude within the first year after CABG despite standard aspirin antiplatelet therapy. However, more potent postoperative platelet inhibition with ticagrelor may improve graft patency. The goal of this study will be to evaluate the efficacy of ticagrelor, as compared to aspirin, for the prevention of saphenous vein graft occlusion following CABG.

STUDY DESIGN

The Ticagrelor Antiplatelet Therapy to Reduce Graft Events and Thrombosis (TARGET) study is a multi-center double-blind randomized controlled trial enrolling patients who have undergone multi-vessel CABG with at least one saphenous vein graft. Patients are being randomized to receive either aspirin 81 mg twice per day or ticagrelor 90 mg twice per day for 2 years starting within 7 days after surgery. The projected enrollment is 150 patients in each arm (300 total patients). Patients will undergo computed tomography (CT) coronary angiography at 1 and 2 years after surgery to assess the incidence of vein graft occlusion and stenosis.

CONCLUSION

To our knowledge, this trial is the first prospective study to evaluate the impact of early postoperative ticagrelor on 1- and 2-year graft patency after CABG. Furthermore, it is also the first trial to use a novel antiplatelet agent as a standalone, without aspirin, after CABG. Should ticagrelor reduce the incidence of postoperative graft occlusion, the results of this study will redefine modern antiplatelet management following coronary bypass surgery (ClinicalTrials.govNCT02053909).

Targeted deep sequencing of the PEAR1 locus for platelet aggregation in European and African American families

Coronary artery disease (CAD) remains a major cause of mortality and morbidity worldwide. The aggregation of activated platelets on a ruptured atherosclerotic plaque is a critical step in most acute cardiovascular events like myocardial infarction. Platelet aggregation both at baseline and after aspirin is highly heritable. Genome-wide association studies (GWAS) have identified a common variant within the first intron of the platelet endothelial aggregation receptor1 (PEAR1), to be robustly associated with platelet aggregation. In this study, we used targeted deep sequencing to fine-map the prior GWAS peak and identify additional rare variants of PEAR1 that account for missing heritability in platelet aggregation within the GeneSTAR families. In this study, 1709 subjects (1043 European Americans, EA and 666 African Americans, AA) from families in the GeneSTAR study were included. In vitro platelet aggregation in response to collagen, ADP and epinephrine was measured at baseline and 14 days after aspirin therapy (81 mg/day). Targeted deep sequencing of PEAR1 in addition to 2kb of upstream and downstream of the gene was performed. Under an additive genetic model, the association of single variants of PEAR1 with platelet aggregation phenotypes were examined. Additionally, we examined the association between the burden of PEAR1 rare non-synonymous variants and platelet aggregation phenotypes. Of 532 variants identified through sequencing, the intron 1 variant, rs12041331, was significantly associated with all platelet aggregation phenotypes at baseline and after platelet inhibition with aspirin therapy. rs12566888, which is in linkage disequilibrium with rs12041331, was associated with platelet aggregation phenotypes but to a lesser extent. In the EA families, the burden of PEAR1 missense variants was associated with platelet aggregation after aspirin therapy when the platelets were stimulated with epinephrine (p = 0.0009) and collagen (p = 0.03). In AAs, the burden of PEAR1 missense variants was associated, to a lesser degree, with platelet aggregation in response to epinephrine (p = 0.02) and ADP (p = 0.04). Our study confirmed that the GWAS-identified variant, rs12041331, is the strongest variant associated with platelet aggregation both at baseline and after aspirin therapy in our GeneSTAR families in both races. We identified additional association of rare missense variants in PEAR1 with platelet aggregation following aspirin therapy. However, we observed a racial difference in the contribution of these rare variants to the platelet aggregation, most likely due to higher residual missing heritability of platelet aggregation after accounting for rs12041331 in the EAs compared to AAs.

Antiplatelet Therapy in Acute Coronary Syndrome

Antiplatelet agents have for decades been used to improve outcomes in patients with acute coronary syndromes and have become increasingly valued, not only for their antithrombotic properties but also for their anti-inflammatory effects. The drug class continues to evolve as novel agents with increasingly efficacious antiplatelet actions are identified. This review will discuss antiplatelet agents, including aspirin, the P2Y₁₂ receptor antagonists and the glycoprotein IIb/IIIa inhibitors, that are currently used to treat patients with unstable angina and myocardial infarction, focusing on their pharmacological properties and the clinical evidence supporting their use.

Comparison of Cyclooxygenase Inhibition with Two Different Doses of Enteric Coated Aspirin in Normal Young and Elderly Subjects and Elderly with Cerebrovascular Disease

There is still controversy about the optimum dose and formulation of aspirin for prophylaxis of thrombo-embolic events in patients with cerebrovascular disease. Enteric coated formulations of aspirin have po tential advantages over rapidly absorbed formulations in terms of fewer side effects and more selective platelet cyclooxygenase inhibition. We compared 7-day courses of 100 mg and 650 mg per day enteric coated aspirin in young, healthy subjects and in two groups of elderly sub jects of 70 years and above, one group without vascular disease and the other with cerebrovascular disease. Prior to aspirin treatment, the elderly with cerebrovascular dis ease had higher levels of the urinary thromboxane A2 (TXA2) metabolite 11-dehydro-TXB2; the mean in the el derly ill was 4,064 ± 1,762 pg/mg creatinine (n = 8) com pared to levels of 982 ± 139 pg/mg creatinine (n = 17) in the young, and 1,560 ± 380 pg/mg creatinine (n = 14) in the healthy elderly (p < 0.05 and p < 0.01, respectively). Aspirin (100 mg) inhibited serum TXB2 generation in all groups, with the greatest percentage inhibition occurring in the elderly with cerebrovascular disease. In the ill el derly serum TXB2 was 1.9 ± 0.05% (n = 8) of control compared to 4.2 ± 0.6% (n = 17, p < 0.05) in the young and 9.4 ± 3.5% (n = 14, p < 0.01) in the healthy elderly. All young and diseased elderly subjects achieved greater than 90% inhibition with 100 mg aspirin, but 4 of 14 healthy elderly subjects achieved less than 90% inhibi tion. The 650-mg dose of aspirin produced further inhibi tion in serum TXB2 in the young and healthy elderly sub jects and inhibited serum TXB2 to greater than 90% of control levels in all subjects. The higher dose also pro duced greater reductions in 11-dehydro-TXB2 levels, and these were statistically significant in the young and ill elderly. Urinary-6-keto PGF1α was not significantly de creased at either dose, except in the elderly ill taking 650 mg a day in whom it was reduced to 55 ± 18% of control (n = 8, p < 0.05). Thus enteric coated aspirin at doses of 100 and 650 mg taken daily for 7 days inhibited platelet cyclooxygenase with relative sparing of endothelial cy clooxygenase. The elderly with cerebrovascular disease were more sensitive to the platelet and endothelial cyclo oxygenase inhibition effects of enteric coated aspirin than the healthy elderly and healthy young groups.

Heparin Dosing and Postoperative Blood Loss in Patients Taking Aspirin

A large number of patients scheduled to undergo elective coronary artery bypass grafting continue to take aspirin along with other antianginal medication up to the day of surgery. Patients taking aspirin preoperatively are known to bleed more in the postoperative period than those not taking aspirin. This study was undertaken to determine whether the method of heparin administration (protocol-based bolus dose versus an individualized dose) affected postoperative blood loss or requirements of blood and blood products in patients taking aspirin preoperatively. In this prospective study, 300 consecutive patients taking aspirin prior to coronary artery bypass graft surgery were randomly assigned to receive heparin either as a protocol-based bolus of 400 IU·kg−1 (group A) or according to a dose-response curve to obtain an activated coagulation time of 500 seconds on cardiopulmonarybypass (group B). Group B required significantly less heparin (mean 275 IU·kg−1)and less protamine than group A. Postoperative blood loss, requirement of blood and blood products, and time spent on hemostasis in group B was significantly less at 24 hours than group A. We concluded that individualized dosing of heparin using a dose-response curve is preferable to a protocol-based bolus heparin dose in patients taking preoperative aspirin.

Evaluation of a Public Education Program Delivered by Firefighters on Early Recognition of a Heart Attack

The Heart Attack Survival Kit (HASK) project is a prospective, randomized trial, testing the effectiveness of an intervention delivered door-to-door by firefighters to increase use of 911 and ingestion of aspirin for symptoms of acute myocardial infarction (AMI) among seniors in King County, Washington. Firefighters visited 24,582seniors in King County, Washington and delivered a Heart Attack Survival Kit. Another 24,191 senior households served as the control group. Outcomes of the program were measured by tracking 911 calls as well as survey data. This study reports on the results of the telephone survey with a random sample of seniors (N = 323) to assess their knowledge of and intentions to act during a heart emergency. Results of a logistic regression analysis showed that being female, be ing younger, and remembering the kit was significantly related to intentions to act appropriately to AMI symptoms. The results are discussed in terms of public education around AMI.

Inpatient management of epistaxis: Outcomes and cost

OBJECTIVE: Evaluate treatments for epistaxis.

STUDY DESIGN AND SETTING: Retrospective review of Nationwide Inpatient Sample (1998-2000).

RESULTS: A total of 9778 admissions with admitting diagnosis “epistaxis” were identified. Among admissions involving 1 treatment, 454 (9.6%) received arterial ligation, 94 (2.0%) embolization, and 4188 (88.4%) nasal packing. There were no differences in length of stay, transfusions, complications, or deaths between groups (all P >0.05). Mean total hospital charges were $6,282 for the packing group, $12,805 for the ligation group, and $17,517 for the embolization group; differences between ligation and packing groups, and embolization and packing groups demonstrated significance ( P >0.05).

CONCLUSIONS: Nasal packing is used commonly for epistaxis that requires inpatient management. Although embolization and arterial ligation are associated with higher hospital charges, complications, transfusion rates, and lengths of stay are similar. Further studies are needed to quantify other outcome measures, such as recurrence rates and patient quality of life.

SIGNIFICANCE: Nasal packing is associated with lower hospital charges and similar complication rates as arterial ligation or embolization. (Otolaryngol Head Neck Surg 2005;132:707-12.)

Endothelial dysfunction in young healthy men is associated with aspirin resistance

The aim of this study was to investigate the relation between endothelial dysfunction and aspirin response in a young healthy population (102 men aged 18-40). Initial concentrations of the NO pathway metabolites (ADMA, l-arginine, SDMA), cardiovascular risk markers, oxidative stress markers (MDA, thiol index), sICAM1, sVCAM1, PAI-1, sE-selectin, sP-selectin, VEGF, thromboxane B2, 6-keto-PGF1α and arachidonate-induced platelet aggregation (to separate aspirin resistant from sensitive group) were measured. Flow-mediated-vasodilation (FMD) was measured before and after intravenous infusion of 16.0 g of l-arginine. Measurements were repeated following aspirin administration (75 mg/24 h) for 4 days. Both groups were homogenous regarding demographic and biochemical characteristics reflecting cardiovascular risk. Aspirin resistant subjects were characterized by lower baseline FMD and higher FMD following aspirin and l-arginine treatment, as compared to aspirin sensitive control. MDA and nitrotyrosine were greater, whereas thiol index was lower in aspirin resistant men. The sICAM1, sVCAM1, PAI-1, sE-selectin, sP-selectin and VEGF levels were similar in the analyzed groups. Thromboxane in aspirin resistant subjects was greater both at baseline and following aspirin therapy. However, a significant decrease following aspirin treatment was present in both groups. Aspirin resistance in young men is associated with endothelial dysfunction, which could be due to oxidative stress resulting from lipid peroxidation.

Circadian patterns of ST elevation myocardial infarction in the new millennium

OBJECTIVE

Nearly four decades ago, a circadian pattern of acute myocardial infarction (AMI) with a peak in the early morning waking hours was described. The goal of the present study was to determine whether major changes in lifestyle and significant advances in medical therapy have altered this pattern in the intervening years.

DESIGN

Retrospective chart review.

SETTING

Tertiary care hospital in central Wisconsin.

METHODS

We examined circadian patterns of ST elevation myocardial infarction (STEMI) in 519 patients diagnosed with STEMI over a 5-year period. Time of symptom onset was obtained from patient self-reports in the medical record and was recorded over 24 hours.

RESULTS

We observed a circadian pattern of STEMI occurrence with a morning peak at approximately 11:30 AM. This pattern was highly significant in patients who were not using beta-blockers (P <0.0001) and had no history of diabetes (P <0.0001), but was otherwise absent. The circadian pattern appeared to be attenuated in patients of a younger age, female gender, or who used statins or aspirin. Peak STEMI occurrence was earlier in smokers than non-smokers.

CONCLUSIONS

Despite significant lifestyle changes and medical advances in the nearly four decades since a circadian pattern of AMI occurrence was first described, patients with STEMI had a circadian pattern of symptom onset with a morning peak. Use of beta-blockers and a history of diabetes mellitus abolished this pattern. Other modifying factors, including medications, age, and gender attenuated, but did not abolish, the circadian pattern.

Long-term aspirin pretreatment in the prevention of cerulein-induced acute pancreatitis in rats

AIM: To investigate the effects of long term pretreatment with low-, medium- and high-dose aspirin (acetylsalicylic acid, ASA) on a model of acute pancreatitis (AP) induced in rats.

METHODS: Forty male Wistar rats were used. Three experimental groups, each consisting of eight animals, received low- (5 mg/kg per day), medium- (150 mg/kg per day) and high-dose (350 mg/kg per day) ASA in supplemented pellet chow for 100 d. Eight animals, serving as the AP-control group, and another eight, serving as reference value (RV) group, were fed with standard pellet chow for the same period. After pretreatment, AP was induced in the experimental animals by intraperitoneal administration of cerulein (2 × 50 μg/kg), while the RV group received saline in the same way. Twelve hours after the second injection, the animals were sacrificed. Pancreatic tissue and plasma samples were collected. One part of the collected pancreatic tissues was used for histopathological evaluation, and the remaining portion was homogenized. Cytokine levels [tumor necrosis factor, interleukin (IL)-1β, IL-6], hemogram parameters, biochemical parameters (amylase and lipase), nuclear factor-κB, aspirin triggered lipoxins and parameters related to the antioxidant system (malondialdehyde, nitric oxide, hemeoxygenase-1, catalase and superoxide dismutase) were measured.

RESULTS: Cerulein administration induced mild pancreatitis, characterized by interstitial edema (total histopathological score of 5.88 ± 0.44 vs 0.25 ± 0.16, P < 0.001). Subsequent pancreatic tissue damage resulted in an increase in amylase (2829.71 ± 772.48 vs 984.57 ± 49.22 U/L, P = 0.001) and lipase (110.14 ± 75.84 U/L vs 4.71 ± 0.78 U/L, P < 0.001) in plasma, and leucocytes (6.89 ± 0.48 vs 4.36 ± 0.23, P = 0.001) in peripheral blood. Cytokines, IL-1β (18.81 ± 2.55 pg/μg vs 6.65 ± 0.24 pg/μg, P = 0.002) and IL-6 (14.62 ± 1.98 pg/μg vs 9.09 ± 1.36 pg/μg, P = 0.04) in pancreatic tissue also increased. Aspirin pretreatment reduced the increase in the aforementioned parameters to a certain degree and partially improved the histopathological alterations caused by cerulein. No evidence of side effects related to chronic ASA administration (e.g., inflammation or bleeding) was observed in the gastrointestinal tract in macroscopic and histopathological examination.

CONCLUSION: Long term ASA pretreatment could prevent and/or ameliorate certain hematological, serological and histological alterations caused by cerulein-induced AP.

Targeted deep resequencing identifies coding variants in the PEAR1 gene that play a role in platelet aggregation

Platelet aggregation is heritable, and genome-wide association studies have detected strong associations with a common intronic variant of the platelet endothelial aggregation receptor1 (PEAR1) gene both in African American and European American individuals. In this study, we used a sequencing approach to identify additional exonic variants in PEAR1 that may also determine variability in platelet aggregation in the GeneSTAR Study. A 0.3 Mb targeted region on chromosome 1q23.1 including the entire PEAR1 gene was Sanger sequenced in 104 subjects (45% male, 49% African American, age = 52±13) selected on the basis of hyper- and hypo- aggregation across three different agonists (collagen, epinephrine, and adenosine diphosphate). Single-variant and multi-variant burden tests for association were performed. Of the 235 variants identified through sequencing, 61 were novel, and three of these were missense variants. More rare variants (MAF<5%) were noted in African Americans compared to European Americans (108 vs. 45). The common intronic GWAS-identified variant (rs12041331) demonstrated the most significant association signal in African Americans (p = 4.020×10(-4)); no association was seen for additional exonic variants in this group. In contrast, multi-variant burden tests indicated that exonic variants play a more significant role in European Americans (p = 0.0099 for the collective coding variants compared to p = 0.0565 for intronic variant rs12041331). Imputation of the individual exonic variants in the rest of the GeneSTAR European American cohort (N = 1,965) supports the results noted in the sequenced discovery sample: p = 3.56×10(-4), 2.27×10(-7), 5.20×10(-5) for coding synonymous variant rs56260937 and collagen, epinephrine and adenosine diphosphate induced platelet aggregation, respectively. Sequencing approaches confirm that a common intronic variant has the strongest association with platelet aggregation in African Americans, and show that exonic variants play an additional role in platelet aggregation in European Americans.

Anti-platelet activity of diacetylated obovatol through regulating cyclooxygenase and lipoxygenase activities

Obovatol has been reported biological activities such as muscle relaxative, anti-gastric ulcer, anti-allergic and anti-bacterial activities. The present study was undertaken to investigate the effect of diacetylated obovatol, an obovatol derivative, on rabbit platelet aggregation, and their possible molecular mechanisms. Effects of diacetylated obovatol on platelet activation including aggregation and serotonin secretion were examined. In addition, we investigated the effect of diacetylated obovatol on archidonic acid and metabolites liberation and intracellular calcium mobilization. Diacetylated obovatol concentration-dependently inhibited the washed rabbit platelet aggregation induced by collagen and arachidonic acid, suggesting that diacetylated obovatol may selectively inhibits collagen- and arachidonic acid-mediated signal transduction. In accordance with these results, diacetylated obovatol showed a concentration-dependent decrease in cytosolic Ca(2+) mobilization and serotonin secretion. However, diacetylated obovatol did not inhibit arachidonic acid liberation; on the other hand, diacetylated obovatol inhibited the formation of arachidonic acid metabolites such as thromboxane A(2), prostaglandin D(2) and 12-HETE through interfering with cyclooxygenase (COX)-1 and lipoxygenase (LOX) activities. The results demonstrated that diacetylated obovatol has antiplatelet activities through inhibition of COX-1 and LOX activities.

Aging-shifted prostaglandin profile in endothelium as a factor in cardiovascular disorders

Age-associated endothelium dysfunction is a major risk factor for the development of cardiovascular diseases. Endothelium-synthesized prostaglandins and thromboxane are local hormones, which mediate vasodilation and vasoconstriction and critically maintain vascular homeostasis. Accumulating evidence indicates that the age-related changes in endothelial eicosanoids contribute to decline in endothelium function and are associated with pathological dysfunction. In this review we summarize currently available information on aging-shifted prostaglandin profiles in endothelium and how these shifts are associated with cardiovascular disorders, providing one molecular mechanism of age-associated endothelium dysfunction and cardiovascular diseases.

Aspirin prophylaxis for the prevention of thrombosis: expectations and limitations

Platelets play a very important role in the pathogenesis of acute vascular events leading to thrombosis of the coronary and cerebral arteries. Blockage of these arteries leading to regional ischemia of heart and brain tissues precipitate heart attacks and stroke. Acetyl salicylic acid (Aspirin) has been the drug of choice for over half a century for the primary and secondary prophylaxis of thrombotic events. In spite of its extensive use as an antiplatelet drug for the prevention of vascular thrombosis, there is considerable concern about the degree of protection it offers, to patients under aspirin therapy. In this paper, we explain the phenomenon of aspirin resistance, discuss the limitations of aspirin therapy, and suggest methods to monitor "at-risk" individuals. Ability to monitor and determine at risk patients will provide opportunities for the clinicians to customize antiplatelet therapies.

Long-term prognosis of diabetic patients with acute myocardial infarction in the era of acute revascularization

BACKGROUND

The long-term prognosis of diabetic patients with acute myocardial infarction (AMI) treated by acute revascularization is uncertain, and the optimal pharmacotherapy for such cases has not been fully evaluated.

METHODS

To elucidate the long-term prognosis and prognostic factors in diabetic patients with AMI, a prospective, cohort study involving 3021 consecutive AMI patients was conducted. All patients discharged alive from hospital were followed to monitor their prognosis every year. The primary endpoint of the study was all-cause mortality, and the secondary endpoint was the occurrence of major cardiovascular events. To elucidate the effect of various factors on the long-term prognosis of AMI patients with diabetes, the patients were divided into two groups matched by propensity scores and analyzed retrospectively.

RESULTS

Diabetes was diagnosed in 1102 patients (36.5%). During the index hospitalization, coronary angioplasty and coronary thrombolysis were performed in 58.1% and 16.3% of patients, respectively. In-hospital mortality of diabetic patients with AMI was comparable to that of non-diabetic AMI patients (9.2% and 9.3%, respectively). In total, 2736 patients (90.6%) were discharged alive and followed for a median of 4.2 years (follow-up rate, 96.0%). The long-term survival rate was worse in the diabetic group than in the non-diabetic group, but not significantly different (hazard ratio, 1.20 [0.97-1.49], p = 0.09). On the other hand, AMI patients with diabetes showed a significantly higher incidence of cardiovascular events than the non-diabetic group (1.40 [1.20-1.64], p < 0.0001). Multivariate analysis revealed that three factors were significantly associated with favorable late outcomes in diabetic AMI patients: acute revascularization (HR, 0.62); prescribing aspirin (HR, 0.27); and prescribing renin-angiotensin system (RAS) inhibitors (HR, 0.53). There was no significant correlation between late outcome and prescription of beta-blockers (HR, 0.97) or calcium channel blockers (HR, 1.27). Although standard Japanese-approved doses of statins were associated with favorable outcome in AMI patients with diabetes, this was not statistically significant (0.67 [0.39-1.06], p = 0.11).

CONCLUSIONS

Although diabetic patients with AMI have more frequent adverse events than non-diabetic patients with AMI, the present results suggest that acute revascularization and standard therapy with aspirin and RAS inhibitors may improve their prognosis.

The PFA-100® detects sub-optimal antiplatelet responses in patients on aspirin

Although it is suspected that some patients with acute coronary syndromes (ACS) could have a sub-optimal response to aspirin (SASAR), currently a fixed dose of ASA is long-term used in all individuals. This study was designed to determine SASAR and whether a SASAR is a predictor for recurrence of ischemic events in patients on low-dose ASA with a previous ACS. One hundred patients taking ASA 100 mg/day were assessed at 1 and 6 months after a first ACS. SASAR was initially defined as a failure of the ASA treatment to significantly prolong the closure time in the Platelet Function Analyzer (PFA-100). SASAR in these samples was reconfirmed by conventional aggregometry. TXB2 levels were determined in plasma. At one month 49 patients showed SASAR in the PFA-100; only 25 of them showed SASAR by conventional aggregometry. At six months, 39 of 81 patients showed SASAR by PFA-100, but conventional aggregometry detected SASAR in only 12 of the 39 patients. TXB2 levels were significantly higher in patients with SASAR. Five patients with SASAR, by both tests, died during follow-up (p = 0.013). The PFA-100 detected a high rate of SASAR in patients with ACS. This instrument could be used to screen for suboptimal response to the antiplatelet action of ASA. Whether persistence of SASAR could relate to a higher risk of recurrence and how adjusting the dose of ASA could reduce the rate of SASAR are issues that deserve further investigations.

Effect of statins and aspirin alone and in combination on clinical outcome in dyslipidaemic patients with coronary heart disease.A subgroup analysis of the GREACE study

DECLARATION OF INTEREST

The GREACE study was conducted independently; no Company or Institution has supported it financially. Some of the authors have attended conferences and participated in other trials sponsored by various pharmaceutical companies. We assessed the possible 'synergy' of statins and aspirin (ASA) in reducing vascular events in patients with coronary heart disease, in a post hoc analysis of the GREek Atorvastatin and Coronary-heart-disease Evaluation (GREACE) study. All patients (n = 1600) were divided into four groups according to long-term treatment: Group A (n = 787; statin + ASA), B (n = 93; statin - no ASA), C (n = 599; no statin - on ASA) and D (n = 121; no statin - no ASA). From all patients 692 were either on a statin or ASA monotherapy (Groups B + C). Relative risk reductions (RRRs) in 'all events' (primary endpoint) between groups were assessed. During the 3-year follow-up there were 292 cardiovascular events; 92 (12% of patients) in Group A, 14 (15%) in group B, 144 in Group C (24%) and 42 events in Group D (35%). The total number of events in Group B + C was 158 (23%). The RRRs in the primary endpoint were: Group A versus B 24% (P = 0.1912), A versus C 51% (P < 0.0001), A versus B + C 49% (P < 0.0001) and A versus D 71% (P < 0.0001). The RRRs in Group B versus C was 36% (P = 0.0431) and B versus D 57% (P = 0.0012), while in C versus D 33% (P = 0.0084). Our findings show that statins and ASA have an additive effect in reducing cardiovascular events. Aggressive statin use in the absence of ASA also substantially reduced cardiovascular events. Treatment with ASA in the absence of statin use reduced clinical events in comparison to patients not treated with either drug.

Attenuated severity of new acute ischemic events in patients with previous coronary heart disease receiving long-acting nitrates

BACKGROUND

Platelet aggregation and secondary vasoconstriction are key events in the genesis of acute coronary syndromes.

HYPOTHESIS

Since nitrates have vasodilatory and antiaggregant effects, treatment with long-acting nitrates at the time of onset of acute coronary syndromes could be associated with attenuation of their severity.

METHODS

A consecutive series of 533 patients with acute coronary syndrome and past history of coronary artery disease admitted to the Cardiology Service of a general hospital was studied. A specific questionnaire assessed the use of nitrates and other relevant drugs, as well as other clinical variables. The diagnosis of unstable angina or acute myocardial infarction (MI) was established according to clinical, electrocardiographic, and enzymatic criteria.

RESULTS

In the whole cohort, 169 patients had MI and 364 had unstable angina. Previous use of long-acting nitrates was significantly more common in patients with unstable angina (56%) than in those with MI (37%) (p < 0.0001). Multivariate analysis identified being a nonsmoker [odds ratio: 95%, confidence limits (CL) 0.37, 0.23-0.59], previous unstable angina (CL 0.62, 0.41-0.92), use of aspirin (CL 0.58, 0.41-0.92), and use of long-acting nitrates (CL 0.61, 0.40-0.93) as the independent predictors of the development of unstable angina rather than MI; of these the combination of nitrates and aspirin was the strongest predictor.

CONCLUSIONS

Long-acting nitrates as well as aspirin are suggested to have a protective or modifying effect on the development of acute coronary syndromes, favoring unstable angina rather than acute MI.

Leukocyte count is associated with increased platelet reactivity and diminished response to aspirin in healthy individuals with a family history of coronary artery disease

BACKGROUND

Markers of systemic inflammation, including blood leukocyte count, are associated with increased cardiovascular risk, but the mechanisms underlying this association are unclear. Leukocytes may promote platelet reactivity and thrombus formation, providing a basis for increased risk, but a relation between leukocyte count and platelet function has not been studied.

METHODS

We evaluated the relation of blood leukocyte count, C-reactive protein (CRP), and interleukin-6 (IL-6) to platelet aggregation to collagen, ADP and arachidonic acid, and to urinary excretion of 11-dehydro thromboxane B2. Studies were conducted in 1600 individuals (45.0+/-12.9 years, 42.7% male) at risk for coronary artery disease (CAD) before and after low dose aspirin.

RESULTS

At baseline, platelet reactivity increased with increasing quartile of leukocyte count (median counts for each quartile were normal) for all measures of platelet function (P<0.0001). These relations were unchanged by aspirin. The relation between leukocyte count and each measure of platelet reactivity remained significant (P<0.05) after multivariable adjustment for CRP, IL-6, cardiac risk factors, hematologic variables, and platelet thromboxane production. CRP and IL-6 were independently associated with few measures of platelet reactivity.

CONCLUSIONS

Increasing quartile of leukocyte count, even within the normal range, is associated with increasing platelet reactivity in individuals at risk for CAD. This relationship is not altered by aspirin and is independent of inflammatory markers and platelet thromboxane production. Additional studies are needed to determine the mechanism(s) for this association and therapies to reduce cardiovascular risk in patients with elevated leukocyte counts.

Non-compliance is the predominant cause of aspirin resistance in chronic coronary arterial disease patients

Background

Our previous publication showed that 9% of patients with a history of myocardial infarction MI. could be labeled as aspirin resistant; all of these patients were aspirin resistant because of non-compliance. This report compares the relative frequency of aspirin resistance between known compliant and non-compliance subjects to demonstrate that non-compliance is the predominant cause of aspirin resistance.

Methods

The difference in the slopes of the platelet prostaglandin agonist (PPA) light aggregation curves off aspirin and 2 hours after observed aspirin ingestion was defined as net aspirin inhibition.

Results

After supposedly refraining from aspirin for 7 days, 46 subjects were judged non-compliant with the protocol. Of the remaining 184 compliant subjects 39 were normals and 145 had a past history of MI. In known compliant subjects there was no difference in net aspirin inhibition between normal and MI subjects. Net aspirin inhibition in known compliant patients was statistically normally distributed. Only 3% of compliant subjects (2 normals and 5 MI) had a net aspirin inhibitory response of less than one standard deviation which could qualify as a conservative designation of aspirin resistance. A maximum of 35% of the 191 post MI subjects could be classified as aspirin resistant and/or non-compliant: 9% aspirin resistant because of non-compliance, 23% non-compliant with the protocol and possibly 3% because of a decreased net aspirin inhibitory response in known compliant patients.

Conclusion

Our data supports the thesis that the predominant cause of aspirin resistance is noncompliance.

Pharmacogenomics of platelet responsiveness to aspirin

Aspirin is the most widely used drug in the world for cardiovascular protection. Aspirin's ability to suppress platelet function varies widely among individuals and lesser suppression of platelet function is associated with increased risk of myocardial infarction, stroke and cardiovascular death. Platelet response to aspirin is a complex phenotype involving multiple genes and molecular pathways. Aspirin response phenotypes can be categorized as directly or indirectly related to cyclooxygenase-1 (COX-1) activity, with phenotypic variation indirectly related to COX-1 being much more prominent. Recent data indicate that variability in platelet response to aspirin is genetically determined, but the specific gene variants that contribute to phenotypic variation are not known. An understanding of the relationship between genotype, aspirin response phenotype and clinical outcome will help to bring about a personalized approach to antiplatelet therapy that maximizes antithrombotic benefit whilst minimizing bleeding risk for individual patients.

Therapy with statins and aspirin enhances long-term outcome of percutaneous coronary intervention

Aspirin is the standard therapy applied after coronary intervention, and statins are also prescribed to prevent secondary coronary heart disease. We assessed the ability of a combination of statins and aspirin to improve the longterm prognosis of patients after percutaneous coronary intervention (PCI). We collected data from 575 consecutive patients who underwent PCI. The patients were divided into groups depending on the presence or absence of statin or aspirin therapy as follows: both statin and aspirin (Group B: n = 190; 33%); aspirin only (Group A: n = 236; 41.1%); statin only (Group S: n = 53; 9.2%S); neither drug (Group N: n = 96; 16.7%). Data were statistically assessed using the Cox proportional hazard model for multivariate analysis with adjustment of baseline convariates. Sixty-eight patients died during follow-up (11 +/- 3 years). Multivariate analysis showed that compared with group N, both groups S and A were independent predictors for survival from all causes [group S: hazards ratio (HR) 0.29, 95% confidence interval (CI) 0.10-0.81, P = 0.019; group A: HR 0.31, 95% CI 0.17-0.56, P < 0.0001] and cardiovascular (CV) death (group S: HR 0.16, 95% CI 0.04-0.73, P = 0.018; group A: HR 0.12, 95% CI 0.05-0.30, P < 0.001). risk for all causes and CV death was significantly lower in Group B (HR 0.25, 95% CI 0.12-0.53, P < 0.0001 and HR 0.10, 95% CI 0.03-0.31, P < 0.0001, respectively). Therapy with statins plus aspirin improves long-term clinical outcome in patients after PCI.

From pathophysiology to targeted therapy for atherothrombosis: A role for the combination of statin and aspirin in secondary prevention

Atherothrombosis results from direct interaction between the atherosclerotic plaque and arterial thrombosis, and underlies most forms of cardiovascular disease (CVD). The pathophysiology of atherosclerosis is now recognised to involve endothelial dysfunction and dyslipidemia with cholesterol accumulation, as well as critical immuno-inflammatory and apoptotic dimensions. Erosion or rupture of a vulnerable, lipid-rich, inflammatory atherosclerotic plaque triggers the formation of a platelet-rich thrombus that may partially or completely occlude the artery, with resultant clinical scenarios including stable and unstable angina, acute myocardial infarction (MI) and ischaemic stroke. Insight into the pathophysiology of atherothrombosis indicates that an integrated risk factor approach, focusing particularly on management of dyslipidaemia (with a statin) and thrombosis (with aspirin), may constitute an optimal therapeutic approach. Both agents have established roles in secondary prevention. Statin action on atherogenic lipoproteins mediates plaque stabilisation, modification of plaque morphology and attenuation of inflammation, and may lead to plaque regression, while aspirin reduces platelet activation and aggregation, decreases release of inflammatory cytokines at sites of vascular injury and attenuates vasoconstriction. Given these complementary modes of action, this combination would be a logical choice for reducing atherothrombotic risk in patients with CVD. Meta-analysis of 5 major clinical studies has demonstrated that the combination of pravastatin plus aspirin was significantly more effective than either agent alone in reducing the relative risk of key cardiovascular endpoints including MI and ischaemic stroke. This combination may therefore represent an important, cost-efficient therapeutic approach to reduction of cardiovascular risk and prevention of recurrent events in stable CVD.

Aspirin and PPAR-α activators inhibit monocyte chemoattractant protein-1 expression induced by high glucose concentration in human endothelial cells

Activated endothelial cells express monocyte chemoattractant protein-1 (MCP-1), a chemokine which is reportedly involved in the recruitment of plasma monocytes in the early stages of atherosclerosis. Since accelerated atherosclerosis is the main complication of diabetes and both diseases encompass an inflammatory reaction, we hypothesized that the anti-inflammatory drugs, aspirin and peroxisome proliferator-activated receptor (PPAR-alpha) activators (fenofibrate and clofibrate), could have an effect on the high glucose-induced MCP-1 expression in endothelial cells. To test this assumption, as well as the possible mechanisms involved, the MCP-1 expression and secretion, the reactive oxygen species levels, nuclear factor-kB (NF-kB) and activator protein-1 (AP-1) expression were determined in human endothelial cells exposed to high glucose concentrations in the presence of aspirin, fenofibrate and clofibrate. Human endothelial cells kept in normal glucose concentration in the absence of drugs were used as control. The results showed that (i) aspirin, fenofibrate and clofibrate decrease significantly the MCP-1 expression and secretion in human endothelial cells; (ii) the high glucose up-regulated expression of MCP-1 in endothelial cells was significantly reduced by inhibitors of NF-kB and reactive oxygen species; (iii) all drugs notably decrease the level of the reactive oxygen species and activation of NF-kB and AP-1. Together, the findings indicate that in endothelial cells aspirin and PPAR-alpha activators reduce the high glucose-increased expression of MCP-1 by a mechanism that includes the inhibition of reactive oxygen species, and decrease of AP-1 and NF-kB activation.

A community intervention by firefighters to increase 911 calls and aspirin use for chest pain

OBJECTIVES

To test the effectiveness of an intervention, delivered face-to-face by local firefighters, designed to increase utilization of 911 and self-administration of aspirin for seniors experiencing chest pain.

METHODS

King County, Washington was divided into 126 geographically distinct areas that were randomized to intervention and control areas. A mailing list identified households of seniors within these areas. More than 20,000 homes in the intervention areas were contacted by local firefighters. Data on all 911 calls for chest pain and self-administration of aspirin were collected from the medical incident report form (MIRF). The unit of analysis was the area. Firefighters delivered a heart attack survival kit (that included an aspirin) and counseled participants on the importance of aspirin and 911 use for chest pain. Main outcome measures were 911 calls for chest pain and aspirin ingestion for a chest pain event, obtained from the MIRFs that are collected by emergency medical services personnel for 2 years after the intervention.

RESULTS

There were significantly more calls (16%) among seniors on the mailing list in the intervention than control areas in the first year after the intervention. Among the seniors who were not on the mailing list, there was little difference in the intervention and control areas. The results were somewhat sensitive to the analytical model used and to an outlier in the treatment group.

CONCLUSIONS

A community-based firefighter intervention can be effective in increasing appropriate response to symptoms of a heart attack among elders.

Aspirin resistance: mechanisms and clinical implications

Acetylsalicylic acid (aspirin) has been shown to irreversibly interfere with platelet function, an effect that is associated with a reduction in morbid and mortal arterial thrombotic events in multiple clinical studies. This clinical benefit appears to be attenuated by resistance to the antiplatelet effects of aspirin in up to 35% of patients. The mechanisms for aspirin resistance are multifactorial and include noncompliance with aspirin therapy, diabetes mellitus, cell-cell and drug-drug interactions, genetic polymorphisms, and coronary artery disease. It has not been determined what the best laboratory procedure is to screen for aspirin resistance. Those individuals at high risk for aspirin resistance might best be treated with an additional oral antiplatelet drug (eg, clopidogrel) to achieve maximal protection against arterial thrombotic events.

Impact of aspirin treatment on long-term outcome (over 10 years) after percutaneous coronary intervention

Aspirin has been shown to reduce cardiovascular morbidity and mortality following percutaneous coronary intervention (PCI). However, its effects on long-term (over 10 years) mortality have not been fully elucidated. This retrospective study recorded the patient characteristics and admission medication for all patients undergoing PCI over an 8-year period from 1984 to 1992. Follow-up information was available for 748 patients (100%) for a mean of 143.6 +/- 43.4 months. A propensity analysis was performed to adjust for presumed selection biases in the administration of aspirin. The baseline clinical characteristics were similar between the group that received aspirin and the group that did not, except for the administration of statins and PCI procedural success rate. Of the 748 patients, 535 (71.5%) received aspirin treatment at the time of PCI. During the 12-year follow-up, 54 patients died from any cause and 20 patients from cardiac death. Kaplan-Meier analysis showed that aspirin treatment led to a significant reduction in all cause mortality (10% versus 16.4%; P = 0.01) and cardiac death (3.7% versus 8.0%; P = 0.02) compared to other antiplatelet drugs. The hazard ratio (HR) for the total mortality and cardiac mortality rates was adjusted using the Cox-proportional hazard model for confounding variables and propensity score. The all cause (HR, 0.49; 95%CI [0.29-0.80], P = 0.005) and cardiac mortality rates (HR, 0.32; 95%CI [0.14-0.72], P = 0.006) for patients receiving aspirin remained lower than for those not receiving aspirin. Aspirin treatment at the time of PCI significantly reduced the risk of death from any cause and cardiac death. The administration of aspirin had a positive impact on the over 10-year long-term outcomes of patients who underwent PCI.

Molecular aspects of atherogenesis: new insights and unsolved questions

The development of atherosclerotic disease results from the interaction between environment and genetic make up. A key factor in atherogenesis is the oxidative modification of lipids, which is involved in the recruitment of mononuclear leukocytes to the arterial intima--a process regulated by several groups of adhesion molecules and cytokines. Activated leukocytes, as well as endothelial mitochondria, can produce reactive oxygen species (ROS) that are associated with endothelial dysfunction, a cause of reduced nitric oxide (NO) bioactivity and further ROS production. Peroxisome proliferator-activated receptors (PPAR) and liver X receptors (LXR) are nuclear receptors significantly involved in the control of lipid metabolism, inflammation and insulin sensitivity. Also, an emerging role has been suggested for G protein coupled receptors and for the small Ras and Rho GTPases in the regulation of the expression of endothelial NO synthase (eNOS) and of tissue factor, which are involved in thrombus formation and modulation of vascular tone. Further, the interactions among eNOS, cholesterol, oxidated LDL and caveola membranes are probably involved in some molecular changes observed in vascular diseases. Despite the relevance of oxidative processes in atherogenesis, anti-oxidants have failed to significantly improve atherosclerosis (ATS) prevention, while statins have proved to be the most successful drugs.

An Antithrombotic Agent, NQ301, Inhibits Thromboxane A2 Receptor and Synthase Activity in Rabbit Platelets

In previous studies we have reported that NQ301, a synthetic 1,4-naphthoquinone derivative, displays a potent antithrombotic activity, and that this might be due to antiplatelet effect, which was mediated by the inhibition of cytosolic Ca(2+) mobilization in activated platelets. In the present study, the effect of NQ301 on arachidonic acid cascade in activated platelets has been examined. NQ301 concentration-dependently inhibited washed rabbit platelet aggregation induced by collagen (10 microg/ml), arachidonic acid (100 microM) and U46619 (1 microM), a thromboxane A2 receptor agonist, with IC50 values of 0.60+/-0.02, 0.78+/-0.04 and 0.58+/-0.04 microM, respectively. NQ301 also produced a shift to the right of the concentration-effect curve of U46619, indicating a competitive type of antagonism on thromboxane A2/prostaglandin H2 receptor. NQ301 slightly inhibited collagen-induced arachidonic acid liberation. In addition, NQ301 potently suppressed thromboxane B2 formation by platelets that were exposed to arachidonic acid in a concentration-dependent manner, but had no effect on the production of prostaglandin D2, indicating an inhibitory effect on thromboxane A2 synthase. This was supported by thromboxane A2 synthase activity assay that NQ301 concentration-dependently inhibited thromboxane B2 formation converted from prostaglandin H2. Moreover, NQ301 concentration-dependently inhibited 12-hydroxy-5,8,10,14-eicosatetraenoic acid formation by platelets that were exposed to arachidonic acid. Taken together, these results suggest that NQ301 has a potential to inhibit thromboxane A2 synthase activity with thromboxane A2/prostaglandin H2 receptor blockade, and modulate arachidonic acid liberation as well as 12-hydroxy-5,8,10,14-eicosatetraenoic acid formation in platelets. This may also be a convincing mechanism for the antithrombotic action of NQ301.

A large-scale prospective cohort study on the current status of therapeutic modalities for acute myocardial infarction in Japan: rationale and initial results of the HIJAMI Registry

BACKGROUND

In Western countries, several multicenter collaborative studies on acute myocardial infarction (AMI) have provided much information about this disease. In Japan, on the other hand, there have been few cohort studies in which a sufficient number of Japanese patients with AMI were registered during a short period. This fact explains the absence of a database from which strategies for treating Japanese patients with AMI could be established. The purpose of this study was to build a comprehensive database on Japanese patients with AMI to elucidate their characteristics.

METHODS

Between January 1999 and June 2001, we consecutively registered all patients with AMI who were admitted to 17 participating medical institutions, including The Heart Institute of Japan, Cardiology (HIJC), Tokyo Women's Medical University. A standardized case report form was used to register all the patients.

RESULTS

A total of 3,021 consecutive patients was registered (2,136 men, 70.7%; 885 women, 29.3%) with a median age of 69 years [59, 77]. Among the patients, there were 851 elderly individuals (28.2%) > or = 76 years and 1102 patients with diabetes (36.5%). On index electrocardiogram, ST-elevation myocardial infarction was observed in 2,392 patients (79.2%). Within 24 hours after the onset of AMI, coronary angiography was conducted for 2,177 patients (72.1%). Primary percutaneous coronary intervention and coronary thrombolysis were conducted for 1,755 (58.1%) and 491 patients (16.3%), respectively, and percutaneous coronary intervention or coronary artery bypass grafting was additionally carried out in 303 patients. By the time of discharge, coronary angiography and coronary artery bypass grafting were performed in 2,659 (88.0%) and 137 patients (4.5%), respectively. During initial hospitalization, 285 patients died and the overall inhospital mortality rate was 9.4%. During hospitalization, cardiogenic shock and cardiac rupture were observed in 6.1% and 2.8% of the patients, respectively. The inhospital mortality rate is still high in patients with AMI with such mechanical complications and in elderly patients.

CONCLUSION

In our prospective cohort, we showed that Japanese patients with AMI could be characterized as (1) having a disease severity comparable with values observed in Western populations and (2) receiving early reperfusion therapy by PCI, which was used widely and safely, but nevertheless (3) exhibiting a high inhospital mortality rate. Our data indicate that further improvements in therapy for AMI in elderly patients and for AMI with mechanical complications are essential in Japan.

Current medical management of chronic stable angina

Severe atherosclerotic narrowing of one or more coronary arteries is responsible for myocardial ischemia and angina pectoris in most patients with stable angina. The coronary arteries of patients with stable angina also contain many more non-obstructive plaques, which are prone to rupture resulting in acute coronary syndrome (unstable angina, myocardial infarction, sudden ischemic death). Therefore, the medical management must use strategies which not only relieve symptoms and prolong angina free walking but also reduce the incidence of adverse clinical outcomes. Whether any of the approved antianginal drugs, nitrates, beta-blockers, and calcium channel blockers reduce the incidence of adverse clinical outcomes in patients with stable angina has not been studied to date. Published data shows that percutaneous coronary revascularization procedures and coronary bypass surgery are effective in relieving angina but these procedures do not reduce mortality or the incidence of myocardial infarction compared to anti-anginal drug therapy. From the available data, an initial trial of medical treatment with anti-anginal drugs and strategies to reduce adverse clinical outcomes (smoking cessation, daily aspirin, treatment of dyslipidemias and hypertension) is indicated in most patients with stable angina pectoris. The initial choice of drug will depend on the presence or absence of comorbid conditions. Patients who do not respond to medical therapy or do not wish to take anti-anginal drugs and whose life style is limited because of anginal symptoms should be offered percutaneous revascularization procedures with or without stent placement or coronary bypass surgery. New drug-coated stents hold promise but long-term data and large-scale trials assessing the continued long-term improvement in symptoms and reduction of adverse outcomes is needed before offering such devices to all patients with stable angina. Newer medical therapies such as metabolic modulators and sinus rate lowering drugs also hold promise but need further evaluation. Patients who have refractory angina despite optimal medical therapy and are not candidates for revascularization procedures may be candidates for some new techniques of enhanced external Counterpulsation, Spinal Cord Stimulation, sympathectomy or direct transmyocardial revascularization. The usefulness of these techniques, however, needs to be confirmed in large randomized trials.

Antiplatelet and Antithrombin Therapy for Early Management of Acute Coronary Syndromes

Acute coronary syndromes (ACS) are defined as either unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), or ST-segment elevation myocardial infarction (STEMI). Their management is continuously evolving in terms of pharmacologic therapy. The usual cause of ACS is the disruption of an atherosclerotic plaque leading to formation of a thrombus within a coronary artery. Initial antiplatelet and antithrombin therapy for patients with ST-segment elevation (STE) ACS includes aspirin and unfractionated heparin (UFH). Patients presenting to the hospital early may undergo percutaneous intervention (PCI) with administration of additional medications such as clopidogrel and abciximab or may receive a fibrinolytic agent. Patients with non-ST-segment elevation (NSTE) ACS receive aspirin, clopidogrel, either a low-molecular-weight heparin or UFH, and, in selected patients, a glycoprotein (GP) IIb/IIIa receptor blocker. All of these agents have shown benefit when administered to patients with ACS, but results vary depending on the type of syndrome, timing of administration, and patient’s overall risk. Their mechanism of action, role in ACS, clinical practice recommendations, adverse effects, and monitoring are reviewed. Some inherent limitations to agents such as aspirin and UFH require the need for newer treatment approaches. Therefore, newer classes of drugs such as the direct thrombin inhibitor bivalirudin and the selective factor Xa inhibitor fondaparinux are being explored as alternatives to heparins for ACS management.