Decline in platelet count and long-term post-PCI ischemic events: implication of the intra-aortic balloon pump

An Updated Review on Glycoprotein IIb/IIIa Inhibitors as Antiplatelet Agents: Basic and Clinical Perspectives

The glycoprotein (GP) IIb/IIIa receptor is found integrin present in platelet aggregations. GP IIb/IIIa antagonists interfere with platelet cross-linking and platelet-derived thrombus formation through the competition with fibrinogen and von Willebrand factor. Currently, three parenteral GP IIb/IIIa competitors (tirofiban, eptifibatide, and abciximab) are approved for clinical use in patients affected by percutaneous coronary interventions (PCI) in the location of acute coronary syndrome (ACS). GP IIb/IIIa antagonists have their mechanism of action in platelet aggregation prevention, distal thromboembolism, and thrombus formation, whereas the initial platelet binding to damage vascular areas is preserved. This work is aimed to provide a comprehensive review of the significance of GP IIb/IIIa inhibitors as a sort of antiplatelet agent. Their mechanism of action is based on factors that affect their efficacy. On the other hand, drugs that inhibit GP IIb/IIIa already approved by the FDA were reviewed in detail. Results from major clinical trials and regulatory practices and guidelines to deal with GP IIb/IIIa inhibitors were deeply investigated. The cardiovascular pathology and neuro-interventional surgical application of GP IIb/IIIa inhibitors as a class of antiplatelet agents were developed in detail. The therapeutic risk/benefit balance of currently available GP IIb/IIa receptor antagonists is not yet well elucidated in patients with ACS who are not clinically evaluated regularly for early cardiovascular revascularization. On the other hand, in patients who have benefited from PCI, the antiplatelet therapy intensification by the addition of a GP IIb/IIIa receptor antagonist (intravenously) may be an appropriate therapeutic strategy in reducing the occurrence of risks of thrombotic complications related to the intervention. Development of GP IIb/IIIa inhibitors with oral administration has the potential to include short-term antiplatelet benefits compared with intravenous GP IIb/IIIa inhibitors for long-term secondary preventive therapy in cardiovascular disease. But studies showed that long-term oral administration of GP IIb/IIIa receptor inhibitors has been ineffective in preventing ischemic events. Paradoxically, they have been linked to a high risk of side effects by producing prothrombotic and pro-inflammatory events.

Antithrombotic Therapy for ACS in Elderly Patients

BACKGROUND

Patients over 75 account for more than one third of those presenting with myocardial infarction and more than 50% of intrahospital mortality. There are no specific guidelines for the management of acute coronary syndromes (ACS) in the elderly.

SETTING

Although antithrombotic therapy seems to be effective and safe in such patients, it requires specific precautions and treatment adjustments because of the higher bleeding risk due to comorbidities such as renal function impairment and malnutrition.

RESULTS

Scientific evidence concerning elderly patients is scarce as they are either excluded or underrepresented in most randomized trials. Overall, the antithrombotic therapy needs to be adapted to avoid complications, mainly bleeding complications, without compromising the effectiveness of the treatment in this high-risk population.

CONCLUSION

In the present paper, we review the current treatment strategies in ACS while focusing on data concerning the elderly, according to available data in pivotal trials and in both AHA/ACC and ESC guidelines.

Antithrombotic treatment tailoring and risk score evaluation in elderly patients diagnosed with an acute coronary syndrome

Age is an important prognostic factor in the outcome of acute coronary syndromes (ACS). A substantial percentage of patients who experience ACS is more than 75 years old, and they represent the fastest-growing segment of the population treated in this setting. These patients present different patterns of responses to pharmacotherapy, namely, a higher ischemic and bleeding risk than do patients under 75 years of age. Our aim was to identify whether the currently available ACS ischemic and bleeding risk scores, which has been validated for the general population, may also apply to the elderly population. The second aim was to determine whether the elderly benefit more from a specific pharmacological regimen, keeping in mind the numerous molecules of antiplatelet and antithrombotic drugs, all validated in the general population. We concluded that the GRACE (Global Registry of Acute Coronary Events) risk score has been extensively validated in the elderly. However, the CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA Guidelines) bleeding score has a moderate correlation with outcomes in the elderly. Until now, there have not been head-to-head scores that quantify the ischemic versus hemorrhagic risk or scores that use the same end point and timeline (e.g., ischemic death rate versus bleeding death rate at one month). We also recommend that the frailty score be considered or integrated into the current existing scores to better quantify the overall patient risk. With regard to medical treatment, based on the subgroup analysis, we identified the drugs that have the least adverse effects in the elderly while maintaining optimal efficacy.

Platelet to lymphocyte ratio in the prediction of adverse outcomes after acute coronary syndrome: a meta-analysis

Recent studies have shown platelet to lymphocyte ratio (PLR) to be a potential inflammatory marker in cardiovascular diseases. We performed a meta-analysis to systematically evaluate the prognostic role of PLR in acute coronary syndrome (ACS). A comprehensive literature search up to May 18, 2016 was conducted from PUBMED, EMBASE and Web of science to identify related studies. The risk ratio (RR) with 95% confidence interval (CI) was extracted or calculated for effect estimates. Totally ten studies involving 8932 patients diagnosed with ACS were included in our research. We demonstrated that patients with higher PLR level had significantly higher risk of in-hospital adverse outcomes (RR = 2.24, 95%CI = 1.81–2.77) and long-term adverse outcomes (RR = 2.32, 95%CI = 1.64–3.28). Sensitivity analyses confirmed the stability of our results. We didn’t detect significant publication bias by Begg’s and Egger’s test (p > 0.05). In conclusion, our meta-analysis revealed that PLR is promising biomarker in predicting worse prognosis in ACS patients. The results should be validated by future large-scale, standard investigations.

Unfractionated heparin or low-molecular-weight heparin in the elderly

With the ageing of the general population, clinicians are facing with increased frequency the challenge of administering parenteral anti-coagulation therapy in the elderly, the main indications being venous thromboembolism (VTE), acute coronary syndromes (ACS), atrial fibrillation and bridging therapy. Assessing the risk/benefit ratio is always difficult in this category of patients, because of the higher risk for hemorrhagic events, although in most cases the benefit outweighs the risk, especially in the setting of VTE. The development of early invasive strategies for treating ACS has improved outcomes, while reducing the need for prolonged anticoagulation. For ST-segment elevation acute myocardial infarction (STEMI), primary percutaneous coronary intervention (PCI) is the mainstay treatment with well documented benefits in terms of mortality reduction regardless of the patient's age. However, evidence is less strong regarding early invasive treatment for over 75-year old Non-STEMI patients, resulting in a significant percentage being treated conservatively, including parenteral anticoagulation. This review will focus on the use of parenteral anticoagulation (unfractionated or low-molecular weight heparin) in older patients. We will analyze current guidelines-based parenteral anticoagulation indications, while focusing on specific considerations in the elderly, such as: frailty and comorbidities, pharmacokinetics, the hemorrhagic risk and available clinical evidence. The goal is to offer a comprehensive tool for the clinician managing parenteral anticoagulation in older patients.

Non-vitamin K oral anticoagulant treatment in elderly patients with atrial fibrillation and coronary heart disease

Atrial fibrillation (AF) is the most frequent sustained arrhythmia. Overall prevalence is estimated to 5.5% and the incidence increases with age. As the population ages, the prevalence and costs of AF are expected to increase. AF is the most important cause of stroke in patients >75years. Until recently, Vitamin K antagonists (VKAs) were the only available oral anticoagulants (OACs) evaluated for long-term treatment of patients with AF with or without coronary heart disease (CHD). This situation was challenged by introduction of non-VKA oral anticoagulants (NOACs). In AF, use of NOACs seems to be as effective and safe as VKAs, especially in elderly patients. AF and CHD are frequently associated and the question of antithrombotic management in aging patients is delicate. In elderly patients experiencing a new AF episode after an acute coronary syndrome, triple antithrombotic therapy should be as short as possible in order to decrease the risk of major bleedings. To date, there is no specific study or available guidelines regarding the NOACs use specifically in elderly patients experiencing both AF and CHD. In this review, we try to provide a perspective on NOACs future incorporation into clinical practice in elderly patients with both AF and CHD.

The role of Glycoprotein IIb/IIIa inhibitors in acute coronary syndromes and the interference with anemia

The role played by glycoprotein (GP) IIb/IIIa inhibitors (GPI) has continuously evolved until the most recent Guidelines whereby they were stepped down from class I to class II recommendation for treating acute coronary syndromes (ACS). GPI compete with a wider use of ADP inhibitors and novel anticoagulant drugs although GPI use has greatly narrowed. However, GPI may still have a role. Several criteria were proposed to define post-PCI anemia which is strictly related to bleeding and transfusion. In ACS, it should be important to define anemia in comparative terms versus baseline levels: ≥ 15% of red blood cell decrease should be a practical cut-off value. If one wishes to concentrate on hemoglobin (Hb), a≥2g/dl Hb decrease from baseline should be considered. It is important to recognize post-PCI anemia in the setting of ACS. There are sub-populations exposed to short-term hemorrhagic and/or long-term ischemic risks. Ischemic and hemorrhagic risks need to be carefully evaluated along with thrombocytopenia and its prognostic significance in order to put all these blood and rheological parameters into a clinically oriented perspective on which therapeutical decisions should be based. Definition of high risk procedures (complexity, angiographic characteristics and patient's risk profile, regardless whether STEMI or NSTEMI) may help selecting GPI. There are positive elements in GPI use: efficacy, rapid onset and reversibility of action, absence of pharmacogenomic variability, pharmacoeconomic considerations and the possibility of intracoronary administration. All these elements should be evaluated when selecting these agents for therapeutics.

Oral sirolimus: A possible treatment for refractory angina pectoris in the elderly

Refractory angina pectoris (RAP) is a clinical problem, frequently encountered in the elderly, associated with high health-care costs. Until recently, the goal of RAP treatment aimed at improving the quality of life (QoL) because it was thought that mortality rates were not different between stable angina pectoris and RAP. Our purpose was at determining whether any mortality rate difference exists and whether any novel therapeutical solution might be translated into clinical practice. We therefore performed a literature review to assess current optimal treatment of RAP patients, including all studies involving the use of oral sirolimus and stents, although no consistent evidence was found for any specific treatment to improve survival, apart from minor QoL amelioration. A large mortality difference was seen between RAP and stable angina pectoris. On the other hand, therapeutic approaches to RAP patients showed frequent complications and several contraindications, depending on the procedure. We propose to inhibit instead of stimulating angiogenesis, by giving oral sirolimus, an immunosuppressive drug, thereby decreasing the atherosclerotic process and its evolution. Sirolimus was shown to decrease left ventricular mass (thus indirectly decreasing myocardial oxygen needs and consumption). It might stop and, in some cases, even enable regression of plaque progression. Sirolimus side effects are mild to moderate and wash-out rapidly at treatment discontinuation. Compared with current therapies sirolimus treatment is more health-care cost efficient. It should be important to design a trial in RAP patients powered to reduce mortality and QoL increase.

Impact of Anemia and Dual Antiplatelet Therapy on Mortality in Patients Undergoing Percutaneous Coronary Intervention with Drug-Eluting Stents

The objective was to assess the impact of baseline anemia on all-cause mortality and whether 12-month dual antiplatelet therapy (DAPT) affects 1-year mortality linked to anemia in patients after percutaneous coronary intervention (PCI) with drug-eluting stents (DES). 4109 enrolled patients divided into three groups based on their pre-procedural hemoglobin (Hb) level: Hb < 100 mg/L represented moderate-severe anemia; 100 mg/L ≤ Hb < 120 mg/L for women and 100 mg/L ≤ Hb < 130 mg/L for men represented mild anemia; Hb ≥ 20 mg/L for women and Hb ≥ 130 mg/L for men represented no anemia. DAPT medications were prescribed when patients were discharged. There were significant differences in 30-day and 1-year mortality between moderate-severe anemia and no anemia patients (HR 8.05, 95% CI 1.46 to 44.33, P = 0.017; HR 3.93, 95% CI 1.11 to 13.98, P = 0.034), and in long-term mortality between anemia and no anemia groups (HR 1.82, 95% CI 1.17 to 2.83, P = 0.008 for mild anemia; HR 3.19,95% CI 1.29 to 7.86, P = 0.012 for moderate-severe anemia). There was not significant interaction between 12-month DAPT and anemia on mortality in anemic patients (P for interaction > 0.05). Anemia shows association with increased all-cause mortality in patients undergoing PCI. Twelve-month DAPT does not show synergy with anemia to increase the risk of all-cause 1-year mortality in anemic patients after PCI.

Prognostic significance of post percutaneous coronary intervention thrombocytopenia

Several definitions of post percutaneous coronary intervention (PCI) thrombocytopenia (TC) were formulated. Recent studies demonstrated that a relative drop in platelet count ≥ 25% is the most appropriate criterion. By this definition a population is detected that is exposed not only to increased risk of hemorrhagic complications but also to increased risk of ischemic events, which may appear a paradox. In patients with acute coronary syndromes undergoing PCI, several conditions might be associated with TC: cardiopulmonary by-pass and the presence of extra corporeal membrane oxygenators, intra aortic balloon pump (IABP), cardiogenic shock, thrombolytic drugs and anticoagulant or antiplatelet drugs. Several studies demonstrated that TC and ischemic outcomes are related although it is unclear whether this is a direct relationship or TC is just a secondary effect of another cryptic protagonist. It is suggested that further investigations determine whether there is a real link between TC, a probably well defined covariate, and ischemic outcomes or whether IABP is the joining link between these two variables and whose presence needs in any case be considered in multivariable statistics. Post-PCI TC could be only a secondary effect of IABP use. On turn, the prolonged use of heparin necessarily accompanying the use of IABP, and producing a paradoxical pro-thrombotic TC, might also be implicated.

Intra-aortic balloon counterpulsation - basic principles and clinical evidence

Intra-aortic balloon pump (IABP) counterpulsation has been the most widely used left ventricular assist device for nearly five decades. Due to diastolic inflation and systolic deflation, coronary blood flow is increased and afterload decreased translating into augmentation of oxygen supply and lowering of oxygen demand. However, IABP may be associated with serious complications, including major bleeding, stroke, local and systemic infections and vascular complications. These might counterbalance the potential beneficial hemodynamic effects. In clinical routine, IABP is mainly used in high-risk patients with acute myocardial infarction, especially when complicated by cardiogenic shock. Further, prophylactic IABP use is frequently performed in patients at high risk for hemodynamic instability undergoing elective percutaneous coronary intervention or coronary artery bypass graft surgery. Current evidence, however, does not fully support routine use of IABP in these settings. This review focuses on the basic principles of IABP and discusses current evidence.