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Guidelines recommend treatment with a P2Y12 platelet adenosine diphosphate receptor inhibitor in patients undergoing elective or urgent percutaneous coronary intervention (PCI), but the optimal agent or timing of administration is still not clearly specified. The P2Y12 inhibitor was initially used for its platelet anti-aggregatory action to block thrombosis of the recanalized coronary artery or deployed stent. It is now recognized that these agents also offer potent cardioprotection against a reperfusion injury that occurs in the first minutes of reperfusion if platelet aggregation is blocked at the time of reperfusion. But this is difficult to achieve with oral agents which are slowly absorbed and often require time-consuming metabolic activation. Patients with ST-segment elevation myocardial infarction who usually have a large mass of myocardium at risk of infarction seldom have sufficient time for upstream-administered oral agents to achieve a therapeutic P2Y12 level of inhibition by the time of balloon inflation. However, optimal treatment could be assured by initiating an IV cangrelor infusion shortly prior to stenting followed by subsequent post-PCI transition to an oral agent, that is, ticagrelor, once success of the recanalization and absence of need for surgical intervention are confirmed. Not only should this sequence provide optimal protection against infarction, it should also negate bleeding if coronary artery bypass grafting should be required since stopping the cangrelor infusion at any time will quickly restore platelet reactivity. It is anticipated that cangrelor-induced myocardial salvage will help preserve myocardial function and significantly diminish postinfarction heart failure.

There is conflicting results on whether prior antiplatelet therapy (APT) is associated with poor outcome in spontaneous intracerebral haemorrhage (ICH) patients. To determine whether prior APT is associated with spontaneous ICH, and whether there is a difference between the different types of APT, including cyclooxygenase inhibitor (COX-I), adenosine diphosphate receptor inhibitor (ADP-I) and phosphodiesterase inhibitor (PDE-I). A retrospective study of patients with ICH diagnosed between 2001 and 2013 in the National Health Insurance Research Database. Baseline unbalance between APT and non-APT groups was solved by multivariable adjustment (primary analysis) and propensity score matching (sensitivity analysis). Patients with prior APT had a higher rate of in-hospital death (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.09-1.23) compared to non-APT group. Compared to non-APT group, there was a greater rate of in-hospital death with spontaneous ICH with ADP-I (OR, 1.49; 95% CI, 1.24-1.79) and COX-I (OR, 1.17; 95% CI, 1.09-1.25). PDE-I exhibited no difference in in-hospital death with spontaneous ICH (OR, 1.03; 95% CI, 0.91-1.16) compared to non-APT group. Remarkably, the in-hospital mortality rate was significantly higher in the ADP-I group than in the PDE-I group (hazard ratio, 1.45; 95% CI, 1.17-1.80). In this study, ADP-I and COX-1, but not PDE-I, are the most likely contributors to the association of APT with poor outcome with spontaneous ICH patients. These findings suggest that the complexity of the different mechanism of actions of prior APT can alter the outcome in spontaneous ICH.

Background: Dual antiplatelet therapy combining aspirin with a P2Y12 adenosine diphosphate receptor inhibitor is a therapeutic mainstay for acute coronary syndrome (ACS). However, the optimal choice of P2Y12 adenosine diphosphate receptor inhibitor in elderly (aged ≥65 years) patients remains controversial. We conducted a meta-analysis to compare the efficacy and safety of ticagrelor and clopidogrel in elderly patients with ACS. Methods: We comprehensively searched in Web of Science, EMBASE, PubMed, and Cochrane databases through 29th March, 2021 for eligible randomized controlled trials (RCTs) comparing the efficacy and safety of ticagrelor or clopidogrel plus aspirin in elderly patients with ACS. Four studies were included in the final analysis. A fixed effects model or random effects model was applied to analyze risk ratios (RRs) and hazard ratios (HRs) across studies, and I2 to assess heterogeneity.Results: A total number of 4429 elderly patients with ACS were included in this analysis, of whom 2170 (49.0%) patients received aspirin plus ticagrelor and 2259 (51.0%) received aspirin plus clopidogrel. The ticagrelor group showed a significant advantage over the clopidogrel group concerning all-cause mortality (HR 0.78, 95% CI 0.63–0.96, I2 = 0%; RR 0.79, 95% CI 0.66–0.95, I2 = 0%) and cardiovascular death (HR 0.71, 95% CI 0.56–0.91, I2 = 0%; RR 0.76, 95% CI 0.62–0.94, I2 = 5%) but owned a higher risk of PLATO major or minor bleeding (HR 1.46, 95% CI 1.13–1.89, I2 = 0%; RR 1.40, 95% CI 1.11–1.76, I2 = 0%). Both the groups showed no significant difference regarding major adverse cardiovascular events (MACEs) (HR 1.06, 95% CI 0.68–1.65, I2 = 77%; RR 1.04, 95% CI 0.69–1.58, I2 = 77%).Conclusion: For elderly ACS patients, aspirin plus ticagrelor reduces cardiovascular death and all-cause mortality but increases the risk of bleeding. Herein, aspirin plus ticagrelor may extend lifetime for elderly ACS patients compared with aspirin plus clopidogrel. The optimal DAPT for elderly ACS patients may be a valuable direction for future research studies.

Objectives: To understand the optimal timing of adenosine diphosphate (ADP) receptor inhibitor pretreatment prior to percutaneous coronary intervention (PCI) among acute myocardial infarction (MI) patients. Background: The role of ADP receptor inhibitor pretreatment in this population is unclear. Methods: A total of 9,251 ADP receptor inhibitor-naive MI patients undergoing PCI at 229 TRANSLATE-ACS sites were evaluated. Adjusted risks of in-hospital major adverse cardiovascular events (MACE) and major bleeding were compared among patients with and without pretreatment using inverse probability-weighted propensity adjustment. Results: Of 9,251 patients treated with either prasugrel or clopidogrel during the index MI hospitalization, 4,056 (44%) received pretreatment (ST-segment elevation MI [STEMI] 54.9%, non-STEMI 45.1%); pretreatment was used more commonly among those receiving clopidogrel than prasugrel (52% vs. 20%, P < 0.0001). MACE risks were not significantly different between patients with and without pretreatment (clopidogrel 2.1% vs. 2.2%, adjusted hazard ratio [HR] 1.00, 95% confidence interval [CI] 0.70–1.43; prasugrel 2.1% vs. 2.3%, adjusted odds ratio [OR] 0.82, 95% CI 0.42–1.60). No differences in major bleeding were observed among those receiving versus not receiving pretreatment (clopidogrel 3.1% vs. 3.5%, adjusted HR 0.94, 95% CI 0.65–1.36; prasugrel 2.5% vs. 2.7%, adjusted OR 0.93, 95% CI 0.42–2.02); results were similar when stratified by MI type. Conclusions: ADP receptor inhibitor pretreatment (44%) is commonly used among acute MI patients undergoing PCI in contemporary practice, but no significant differences were found in in-hospital MACE and/or bleeding risks between patients receiving versus not receiving pretreatment, regardless of ADP receptor inhibitor type.

Background and purpose In patients undergoing percutaneous coronary intervention (PCI) with implantation of coronary stents, the risk of stent thrombosis is mitigated with antiplatelet therapy. While current clinical practice is to treat patients with dual antiplatelet therapy (DAPT) combining aspirin with an adenosine diphosphate receptor inhibitor (ADPri), prolonged therapy is associated with heightened bleeding risk. Limiting DAPT to a shorter period after PCI, followed by ADPri monotherapy, may be an attractive strategy for optimizing the balance between thrombotic and bleeding risks. While several randomized controlled trials (RCTs) have been published examining this strategy, the optimal duration of abbreviated DAPT run-in and the ideal choice of ADPri remain uncertain. Methods We undertook a systematic review and meta-analysis of RCTs assessing abbreviated DAPT followed by ADPri monotherapy post coronary stenting. Our primary outcomes were defined as clinically important bleeding, major adverse cardiovascular events (MACE), and all-cause mortality. We searched Ovid MEDLINE and EMBASE from their inceptions to November 2019 with study selection and data extraction performed in duplicate. We pooled data at one year using random effects models; relative risks (RRs) with 95% confidence intervals (95% CIs) were generated using the inverse variance method. Pre-specified sub-group analyses were undertaken according to duration of DAPT and the primary ADPri employed. Results Four trials (n=29084) were eligible for inclusion. Mean age was 65 years and 51.5% of patients were recruited in the context of acute coronary syndrome. Following meta-analysis, the occurrence of clinically significant bleeding events was significantly lower in patients receiving ADPri monotherapy (4 studies; n=29084; RR=0.60; 95% CI, 0.43–0.83; I2=73%; Figure-A), with no significant difference in the rates of all-cause mortality (4 studies; n=29084; RR=0.87; 95% CI, 0.71–1.06; I2=0%; Figure-B) or MACE (4 studies; n=29084; RR=0.90; 95% CI, 0.79–1.03; I2=1%; Figure-C). In subgroup analysis, trends toward lower rates of both all-cause mortality (2 studies; n=23082 participants; RR=0.81; 95% CI, 0.65–1.01; I2=0%; Figure-B) and MACE (2 studies; n=23082 participants; RR=0.90; 95% CI, 0.79–1.03; I2=25%; Figure-C) were seen in the studies employing ticagrelor as opposed to clopidogrel; however, neither analysis reached statistical significance (p-values=0.06 and 0.19, respectively). There was no differential treatment effect based on the duration of abbreviated DAPT prior to ADPri monotherapy in sub-group analysis. Conclusions Following PCI in patients with coronary disease, an abbreviated course of DAPT followed by ADPri monotherapy significantly reduces rates of bleeding with no difference in rates of MACE or all-cause mortality. Future studies are required to conclusively determine whether the use of ticagrelor in this setting may also reduce rates of all-cause mortality. Meta-analysis of included studies Funding Acknowledgement Type of funding source: None

Aims In PEGASUS-TIMI 54, ticagrelor significantly reduced the risk of the composite of major adverse cardiovascular (CV) events by 15–16% in stable patients with a prior myocardial infarction (MI) 1–3 years earlier. We report the efficacy and safety in the subpopulation recommended for treatment in the European (EU) label, i.e. treatment with 60 mg b.i.d. initiated up to 2 years from the MI, or within 1 year after stopping previous adenosine diphosphate receptor inhibitor treatment. Methods and results Of the 21 162 patients enrolled in PEGASUS-TIMI 54, 10 779 patients were included in the primary analysis for this study, randomized to ticagrelor 60 mg (n = 5388) or matching placebo (n = 5391). The cumulative proportions of patients with events at 36 months were calculated by the Kaplan–Meier (KM) method. The composite of CV death, MI, or stroke occurred less frequently in the ticagrelor group (7.9% KM rate vs. 9.6%), hazard ratio (HR) 0.80 [95% confidence interval (CI) 0.70–0.91; P = 0.001]. Ticagrelor also reduced the risk of all-cause mortality, HR 0.80 (0.67–0.96; P = 0.018). Thrombolysis in myocardial infarction major bleeding was more frequent in the ticagrelor group 2.5% vs. 1.1%; HR 2.36 (1.65–3.39; P Conclusion In PEGASUS-TIMI 54, treatment with ticagrelor 60 mg as recommended in the EU label, was associated with a relative risk reduction of 20% in CV death, MI, or stroke. Thrombolysis in myocardial infarction major bleeding was increased, but fatal or intracranial bleeding was similar to placebo. There appears to be a favourable benefit-risk ratio for long-term ticagrelor 60 mg in this population. Clinical trial registration http://www.clinicaltrials.gov NCT01225562

Background Contemporary use of dual antiplatelet therapy and consistency with guideline recommendations in acute coronary syndrome patients undergoing percutaneous coronary intervention (PCI) have not been well characterized. Methods The COAPT was a prospective, observational, multicenter, longitudinal study of patients with myocardial infarction (MI) undergoing PCI. Baseline characteristics, treatment patterns, processes of care, factors associated with switching to and from novel adenosine diphosphate receptor inhibitors (ADPris), and in-hospital outcomes are described. Results Among 2,179 MI patients undergoing PCI during their index hospitalization, 1,328 (60.9%) had ST elevation. Initial ADPri use included clopidogrel in 1,812 (83.2%), prasugrel in 125 (5.7%), and ticagrelor in 242 (11.1%). At discharge, 1,597 patients (73.4%) were prescribed clopidogrel, 220 (10.1%) prasugrel, and 358 (16.5%) ticagrelor. Switching between ADPri therapies during the index hospitalization occurred in 15.3%, 22.4%, and 25.2% of patients initially started on clopidogrel, prasugrel, and ticagrelor, respectively. Most switches over the 15-month study period occurred during the index admission (16.8% of patients vs 4.4% switches postdischarge). Major adverse cardiovascular events occurred in 7.5% of patients during the index hospitalization. In-hospital bleeding events occurred in 6.0% of patients and most were mild. Conclusions Despite randomized trial evidence and guideline recommendations, only a minority of Canadian MI patients undergoing PCI initially received or were discharged on one of the newer ADPri agents. These findings suggest an opportunity to improve upon the appropriate selection of the ADPris at index hospitalization and discharge in Canadian MI patients undergoing PCI.

Although platelet function and pharmacogenomic testing have been studied in clinical trials, their adoption into contemporary practice is unknown.We studied patterns of platelet function and pharmacogenomic testing among 10,048 patients with acute myocardial infarction treated with percutaneous coronary intervention at 226 US hospitals in the TRANSLATE-ACS observational study between April 2010 and October 2012, excluding those receiving research protocol-mandated testing. Inverse probability-weighted propensity adjustment was used to compare 1-year bleeding and major adverse cardiac event risks between patients with and without testing.Overall, 337 (3.4%) patients underwent predischarge platelet function testing, whereas 85 (0.9%) underwent pharmacogenomic testing; 82% and 93% of hospitals never performed any platelet function or pharmacogenomic testing, respectively. Patients undergoing testing were more likely to be on an adenosine diphosphate receptor inhibitor preadmission or to have percutaneous coronary intervention of a previously treated lesion. Tested patients were more likely than nontested patients to be switched from clopidogrel to prasugrel/ticagrelor (25.7% vs 9.7%, P.001) and were more likely to be on prasugrel/ticagrelor 6 months postdischarge (33.8% vs 25.1%, P.001). No significant differences in 1-year bleeding and major adverse cardiac event risks were observed between tested and nontested patients (adjusted hazard ratios 1.06 [95% CI 0.68-1.65] and 1.21 [95% CI 0.94-1.54], respectively).Platelet function and pharmacogenomic testing are rarely performed in contemporary myocardial infarction patients in the United States. When tested, patients were more likely to be treated with higher-potency adenosine diphosphate receptor inhibitors, yet no significant differences in longitudinal outcomes were observed.

Current guideline-based recommendations for oral dual-antiplatelet therapy in an acute coronary syndrome (ACS) include the use of newer adenosine diphosphate receptor inhibitor (ADPri) regimens and agents. The Canadian ACS Reflective Program is a multicenter observational quality-enhancement project that compared the use of ADPri therapy in 2 phases (November 2011-March 2013 and April 2013-November 2013) and also compared ADPri use with previous national data from the Canadian Global Registry of Acute Coronary Events (2000-2008). Of 3099 patients with ACS, 30.6% had ST-segment elevation myocardial infarction (STEMI), 52.3% had non-STEMI, and 17% had unstable angina. There was high use of dual-antiplatelet therapy for ≤ 24 hours, with important increases noted when compared with previous national experience (P for trend, < 0.0001). Clopidogrel was the most commonly used ADPri (82.2%), with lower use of the newer agents ticagrelor (9.0%) and prasugrel (3.1%). Ticagrelor and prasugrel use was most frequent in patients with STEMI undergoing percutaneous coronary intervention PCI (34.3%). There was relatively lower use of ADPri therapy at discharge; it was given mainly to patients who did not undergo PCI (68.2%) and to those with non-ST-elevation ACS (82%). When comparing the 2 consecutive phases of data collection in the ACS Reflective, there was an approximate 3- and 2-fold increase in the early and discharge use of the newer ADPri agents, respectively. In conclusion, there has been a temporal increase in ADPri use compared with previous national experience and an increased uptake of newer ADPri agents. Additional work is needed to identify and address barriers limiting optimal implementation of these newer guideline-recommended agents into routine Canadian practice.

Dual antiplatelet therapy with 75-100 mg Acetyl Salicylic Acid (ASA) and a novel antiplatelet (Adenosine Diphosphate Receptor inhibitor or P2Y12 inhibitor) is the current standard of care following Acute Coronary Syndromes i.e. ST Elevation Acute Coronary Syndrome (STEACS), Non-ST Elevation Acute Coronary Syndrome (NSTEACS) and unstable angina [1]. The Platelet Inhibition and Patient Outcomes (PLATO) trial showed that the oral P2Y12 inhibitor Ticagrelor has significant clinical superiority compared with clopidogrel in the reduction of mortality, recurrent myocardial infarction, instent restenosis and stroke at one year [2]. Despite improved efficacy, Ticagrelor prescription increased peri-procedural and spontaneous bleeding ranging from minor to fatal events [3]. Reduction of blood volume and anaemia can lead to complications such as hypovolaemic shock and myocardial ischaemia due to supply and demand imbalance (type 2 myocardial ischaemia). Bleeding within 30 days post event is shown to impact long-term prognosis adversely. Furthermore, non-access site bleeding increases one year mortality rate to two-fold [4]. Multiple studies with various baseline demographics using various bleeding definitions including Thrombolysis In Myocardial Infarction (TIMI), Bleeding Academic Research Consortium (BARC) and Platelet Inhibition and Patient Trial (PLATO) show different predisposing factors

Background Platelet inhibition is crucial in reducing both short- and long-term atherothrombotic risks in patients with acute coronary syndromes (ACS) managed with percutaneous coronary intervention (PCI). Based on randomised trials, recent recommendations in the current guidelines include the endorsement of prasugrel as a first-choice adenosine diphosphate receptor inhibitor. Yet, there is limited experience with the use of prasugrel in routine practice. Methods The Rijnmond Collective Cardiology Research (CCR) registry is a prospective, observational study that will follow-up 4000 PCI-treated ACS patients in the larger region of Rotterdam, the Netherlands. Based on recently implemented hospital protocols, all patients will receive prasugrel as first-choice antiplatelet agent, unless contraindicated, in accordance with European guidelines, and will be followed for up to 1 year post-discharge for longitudinal assessment of outcomes and bleeding events. This registry exemplifies a collaborative study design that employs a regional PCI registry platform and provides feedback to participating sites regarding their practice patterns, thereby supporting and promoting improvement of quality of care. Conclusion The CCR registry will evaluate the adoption of prasugrel into routine clinical practice and thus, will provide important evidence with regard to the benefits and risks of real-world utilisation of prasugrel as antiplatelet therapy in PCI-treated ACS patients.

The reasons for postdischarge adenosine diphosphate receptor inhibitor (ADPri) switching among patients with myocardial infarction (MI) are unclear. We sought to describe the incidence and patterns of postdischarge ADPri switching among patients with acute MI treated with percutaneous coronary intervention.We used TRANSLATE-ACS (2010-2012) data to assess postdischarge ADPri switching among 8,672 MI patients discharged after percutaneous coronary intervention who remained on ADPri therapy 1 year post-MI. We examined patient-reported reasons for switching, GUSTO moderate or severe bleeding, major adverse cardiovascular events (MACEs), and definite stent thrombosis events around the time of the switch.Among patients still on ADPri therapy 1 year post-MI, 663 (7.6%) switched ADPri during that year. Switching occurred at a median of 50 days postdischarge and most frequently in patients discharged on ticagrelor (64/226; 28.3%), followed by prasugrel (383/2,489; 15.4%) and clopidogrel (216/5,957; 3.6%) (P.001). Among patients discharged on prasugrel, 97.3% of switches were to clopidogrel and 87.5% of ticagrelor switches were to clopidogrel; both of these groups most often cited cost as a reason for switching (43.6% and 39.1%, respectively), whereas 60.7% who switched from clopidogrel cited physician decision as a reason. In the 7 days preceding the switch from clopidogrel, 40 (18.5%) had a MACE and 12 (5.6%) had a definite stent thrombosis event, whereas that from prasugrel or ticagrelor, a GUSTO moderate or severe bleeding event occurred in 1 (0.3%) and 0 patients, respectively.Postdischarge ADPri switching occurred infrequently within the first year post-MI and uncommonly was associated with MACEs or bleeding events.

Background— Little is known about how clinicians use platelet function testing to guide choice and dosing of adenosine diphosphate receptor inhibitor (ADPri) therapy in routine community practice. Methods and Results— The Treatment With Adenosine Diphosphate Receptor Inhibitors: Longitudinal Assessment of Treatment Patterns and Events After Acute Coronary Syndrome (ACS)—Prospective, Open Label, Antiplatelet Therapy Study (TRANSLATE-POPS) was a cluster-randomized trial in which 100 hospitals were assigned access to no-cost platelet function testing versus usual care for acute myocardial infarction patients treated with percutaneous coronary intervention. In both arms, ADPri treatment decisions were left up to the care team. The primary end point was the frequency of ADPri therapy adjustment before discharge. Secondary end points included 30-day rates of major adverse cardiovascular events and Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries–defined bleeding events. Platelet function testing was performed in 66.9% of patients treated in intervention sites versus 1.4% of patients in usual care sites. Intervention arm patients were more likely to have ADPri therapy adjustment than usual care patients (14.8% versus 10.5%, P =0.004; odds ratio 1.68, 95% confidence interval 1.18–2.40); however, there were no significant differences in 30-day major adverse cardiovascular events (4.8% versus 5.4%, P =0.73; odds ratio 0.94, 95% confidence interval 0.66–1.34) or bleeding (4.3% versus 4.2%, P =0.33; odds ratio 0.86, 95% confidence interval 0.55–1.34). One-year outcomes were also not significantly different between groups. An as-treated analysis showed higher incidence of ADPri therapy adjustment among intervention arm patients who received platelet function testing than untested usual care arm (16.4% versus 10.2%, P Conclusions— TRANSLATE-POPS found that when clinicians routinely used platelet function testing, they were more likely to adjust their choice or dosing of ADPri therapy; yet with few changes in therapy overall, significant differences in clinical outcomes were not seen. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01088503.

Acute coronary syndrome (ACS) constitutes a group of pathophysiological entities resulting from reduced blood flow in the coronary arteries leading to decreased or improper functioning or death of heart muscle. Such patients are usually prescribed combination antiplatelet drug therapy, containing acetylsalicylic acid (aspirin) and an adenosine diphosphate receptor inhibitor to prevent recurrence of ischemic events. The combination prophylactic therapy to certain extend has been successful in preventing secondary complications including ischemic/thrombotic events in these patients. However, research is still on for newer advances in anti-thrombotic therapy that can further prevent secondary complications of Acute Coronary Syndrome. Vorapaxar is a newer drug recommended along with aspirin or clopidogril for prevention of recurrence of cardiac events. Vorapaxar, a thrombin receptor antagonist acts by reversible inhibition of the protease-activated receptor-1 (PAR-1). PAR-1 is expressed on platelets, and it inhibits platelet aggregation, both thrombin-induced and thrombin receptor agonist peptide (TRAP)-induced. Various trials world -wide have documented its efficacy as an anti-platelet agent for preventing recurrent cardiovascular ischemic events but at the expense of increased bleeding complications including intracranial haemorrhage (ICH), when compared to standard therapy alone. For the same reason, vorapaxar is contraindicated in patients with prior stroke, transient ischemic attack and ICH. U.S. Food and Drug Administration (FDA) approved vorapaxar in May 2014 as an antiplatelet agent along with standard anti-platelet therapy for the reduction of recurring thrombotic cardiovascular events in patients with a history of myocardial infarction or with peripheral arterial disease. Vorapaxar is developed and marketed by Merck Sharp Dohme and is available by the brand name 'Zontivity' as 2.5 mg oral tablet equivalent to 2.08 mg of vorapaxar sulfate. There are two patents protecting this drug.

Patients with atrial fibrillation affected by an acute coronary syndrome have indications for oral anticoagulation and dual antiplatelet therapy with aspirin and a P2Y12 adenosine diphosphate receptor inhibitor after coronary artery stenting. The concurrent use of all 3 agents, termed triple oral antithrombotic therapy, significantly increases the risk of bleeding. To date, there is a lack of evidence on the proper combination and duration of anticoagulant and antiplatelet agents in patients with indications for both therapies. As such, care has been guided by expert opinion, and there is wide variation in clinician practice. In this review, the latest evidence on the risks and benefits of triple oral antithrombotic therapy in patients with atrial fibrillation after coronary artery stenting is summarized. We discuss the clinical risk scores useful in guiding the prediction of stroke, bleeding, and stent thrombosis. Additionally, we highlight where additional evidence is needed to determine the proper balance of anticoagulant and antiplatelet agents in this patient population.

We would like to congratulate the authors for their study [1]. First, in this study, which is stated to be conducted retrospectively, it is really interesting to be able to standardize the way 180 patients underwent pulmonary functional test (PFT) in terms of the factors affecting blood transfusion. Although the PFTs performed in the patients make this study more valuable than other similar studies in examining the role of chronic obstructive pulmonary disease (COPD) as a risk factor for transfusion, information as to why and on which patients PFTs were performed should be stated. Otherwise, questions may arise on how such a homogenous patient group was obtained. No statistical difference was found between the COPD and non-COPD patients in terms of the crucial preoperative parameters for blood transfusion such as aspirin, coumadin, antiplatelet and adenosine diphosphate receptor inhibitor usage, preoperative haematocrit values, emergency surgery rates, postoperative heparin, coumadin, aspirin and clopidogrel usage, making the study one of great value. As far as can be seen, two parameters showing a significant difference between the groups were smoking and cardiopulmonary bypass (CPB) durations. How would the authors explain that durations are longer in the non-COPD group compared with the COPD group, while proportion of subjects requiring a blood transfusion was greater in the COPD group, although the latter was not statistically significant? The reason for asking this is because present knowledge shows that the rates of blood transfusion increase with the prolongation of CPB duration [2, 3]. In addition, is there any difference between both the groups in terms of redo cases? Redo cases are known to cause more bleeding, and a greater amount of blood and blood products is used in these patients. What are the criteria of blood transfusion in the patients? Is there any difference between both the groups if these criteria had included the postoperative drainage quantity? We believe that this well-planned and standardized study would be much more perfect if the above-mentioned considerations could be clarified.