Comparative evaluation of anti-inflammatory and antioxidant effects of prasugrel versus clopidogrel in patients undergoing percutaneous coronary intervention: A prospective cohort study

Abstract

BACKGROUND:

While both clopidogrel and prasugrel inhibit platelet aggregation, their comparative pleiotropic effects on inflammatory and oxidative stress markers remain unclear.

OBJECTIVE:

To compare the anti-inflammatory and antioxidant potential of clopidogrel and prasugrel given as dual antiplatelet therapy (DAPT) along with aspirin in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI).

SUBJECTS AND METHODS:

In this prospective cohort study, patients aged 18–65 years undergoing PCI for ACS and eligible candidates for DAPT were included. The two study groups were: aspirin + clopidogrel (AC group; n = 52) and aspirin + prasugrel (AP group; n = 52). A change in inflammatory (high-sensitivity C-reactive protein [hs-CRP]) and oxidative stress (total antioxidant capacity [TAOC]) markers at 4 weeks was compared to baseline in two groups.

RESULTS:

A total of 90 patients (46 in AC group and 44 in AP group) completed the study and were included in the analysis. AP group demonstrated a significantly greater reduction in hs-CRP levels at 4 weeks compared to AC group (−7.17 ± 5.95 in AP vs. −4.10 ± 3.81 mg/L in AC groups, P = 0.002). A relatively greater increase in TAOC was also seen in AP group though statistically insignificant (184.25 ± 274.03 in AP vs. 126.67 ± 198.49 in AC groups, P = 0.117). Bleeding and adverse events were comparable in two groups.

CONCLUSIONS:

Prasugrel-based DAPT showed significantly greater reduction in inflammation compared to clopidogrel-based DAPT, with comparable antioxidant benefit and hematological safety indicating a greater pleiotropic benefit of prasugrel than clopidogrel.

Introduction

Dual antiplatelet therapy (DAPT), comprising of aspirin and a P2Y12 antagonist, forms the mainstay of management in patients having acute coronary syndrome (ACS) and/or undergoing percutaneous coronary intervention (PCI), and has established beneficial role in lowering the risk of recurrent ischemic events and stent related thrombotic complications.[1] The recommended duration of DAPT after PCI is a minimum of 6–12 months although indefinite use of aspirin is advised in almost all such cases.[2] Clopidogrel and prasugrel are noncompetitive thienopyridine P2Y12 adenosine diphosphate receptor antagonists and primarily act as inhibitors of platelet aggregation.[1,3] When making a choice of specific P2Y12 antagonist, prasugrel is preferred for maintenance therapy in ACS patients after coronary stenting in the absence of known high risk of bleeding complications and previous history of transient ischemic attack or stroke, while in cases having contraindication, nontolerability, or nonavailability of prasugrel, clopidogrel is generally recommended.[2,4]

Inflammation and oxidative stress have been identified as two major hallmarks in the pathogenesis and progression of ACS.[5,6] Inflammatory processes associated with raised levels of cytokines such as interleukin-6 and tumor necrosis factor-alpha have been linked to endothelial dysfunction and plaque instability. Further, literature evidence demonstrates increased risk of atherosclerotic progression and adverse cardiovascular events in the presence of inflammation.[7] Elevated levels of high-sensitivity C-reactive protein (hs-CRP), another key inflammatory marker, have also been strongly associated with adverse outcomes in ACS reinforcing the significance of recognizing inflammation as a potential therapeutic target in the management of ACS.[8] Besides inflammation, presence of reactive oxygen species (ROS) is associated with lipid peroxidation, vascular inflammation and atherosclerotic plaque destabilization, thereby labelling oxidative stress as another pathognomic feature in ACS.[9] Antioxidant mechanisms in the body, aiming to neutralize ROS, play a major role in alleviating oxidative stress. Total antioxidant capacity (TAOC), an important parameter of the cumulative antioxidative potential in individuals, has been linked to cardiovascular health with lower TAOC levels associated with greater cardiovascular risk and adverse outcomes in ACS.[10]

Clinical research on antiplatelet agents is predominantly centered on their thrombotic and hemorrhagic outcomes and very limited attention has been given to their potential pleiotropic (anti-inflammatory and antoxidative) effects.[11] Given the ever expanding burden of ACS and the endorsed need of administering DAPT for secondary prevention, it is imperative to comprehend the differential effects of these agents on inflammatory and oxidative stress markers, which could provide insights into their broader impact beyond platelet inhibition. The present study was planned to address this existing knowledge gap by comparing the effects of clopidogrel and prasugrel on inflammatory and oxidative stress markers when given as DAPT with aspirin in ACS patients undergoing PCI.

Subjects and Methods

Study design and setting

This was a prospective observational cohort study conducted collaboratively by the departments of Pharmacology and Cardiology in a public tertiary care hospital in Rohtak, Haryana, from July 2023 to October 2024. The study was conducted after approval from the Biomedical Research Ethics Committee of the institute (No. BREC/23/TH-Pharma/07 dated 24.06.2023). Written informed consent was taken from all the participants, and adequate measures to ensure data privacy and subject confidentiality were taken.

Study population

Patients admitted in the cardiac catheterization laboratory and cardiac care unit under the department of Cardiology were assessed for potential eligibility in the study. The study population comprised of patients aged 18–65 years who underwent PCI for ACS and were candidates for DAPT according to the 2016 American College of Cardiology/American Heart Association (ACC/AHA) guideline focused update on duration of DAPT in patients with coronary artery disease (CAD).[12] The choice of the DAPT was made by the treating cardiologist as per the ACC/AHA guidelines and comprised of either of the two regimens – (1) AC group: aspirin (150–300 mg loading dose, 75 mg maintenance) + clopidogrel (300–600 mg loading dose, 75 mg maintenance); or (2) AP group: aspirin (150–300 mg loading dose, 75 mg maintenance) + prasugrel (60 mg loading dose, 10 mg maintenance). All the patients received commercially available drugs available in the hospital pharmacy and there were no subsequent changes in any of the drugs or dosages during the 4-week study observation period. Exclusion criteria were patients already on antiplatelet drugs and patients on monotherapy with aspirin or any P2Y12 antagonist. Patients having present or past history of active bleeding, pregnant or lactating females, and those suffering from other comorbidities such as inflammatory/infective diseases, severe extra cardiac diseases limiting life expectancy, renal or hepatic impairment were also excluded.

Study objectives

The primary objective comprised of change in hs-CRP and TAOC levels at 4 weeks compared to baseline between AP and AC groups. Secondary objectives included (i) change in hemoglobin and hematocrit (packed cell volume [PCV]) values at 4 weeks from baseline; (ii) incidence and severity of bleeding events categorized according to Bleeding Academic Research Consortium (BARC) classification;[13] and (iii) other treatment related adverse events or study drug withdrawal/discontinuations. Patients were instructed to report to the site on occurrence of any bleeding episode or other adverse events.

Estimation of inflammatory and oxidative stress markers

Approximately 4–5 mL venous blood samples were collected from all the included patients at baseline, e.g., before administering first dose of DAPT and after 4 weeks. Serum was separated by centrifugation at 20,000 rotations per minute (rpm) for 5 min and stored at −20°C for further analysis. The levels of hs-CRP, the inflammatory marker, were measured using enzyme-linked immunosorbent assay method as per the instructions provided with the manufacturer’s kit (ichroma™). The TAOC (oxidative stress marker) of biological samples was determined using a colorimetric assay.

Sample size calculation

The primary endpoint for the sample size calculation was taken as the change in hs-CRP levels. The sample size was calculated on the basis of the observed difference in hs-CRP levels between clopidogrel and prasugrel groups in a previous study.[14] With an expected mean (standard deviation [SD]) change in hs-CRP levels in clopidogrel group as 7.8 (10.67) mg/L versus 13.67 (5.96) in prasugrel group, using a two-tailed test with α = 0.05 and β = 0.2, the sample size was calculated as 43 patients in each group. Assuming 20% lost to follow-up, a minimum of total 104 patients needed to be enrolled in both the groups.

Statistical analysis

The data were subjected to Shapiro–Wilk normality test. Categorical variables were expressed as frequencies and percentages, whereas continuous variables were presented as median (interquartile range [IQR]) or mean ± SD depending upon the distribution. Changes in hs-CRP and TAOC levels at 4 weeks compared to baseline between the two groups were compared using Mann–Whitney U-test. Changes in hemoglobin and PCV values between the two groups after 4 weeks were compared using Student’s t-test. Categorical variables were analyzed by Chi-square or Fisher’s exact test, whichever appropriate. All the analyses were performed using IBM SPSS statistics trial version 30.0. P < 0.05 was considered statistically significant.

Results

Out of total 145 patients assessed for eligibility, 104 met the study inclusion criteria who were administered either of the two DAPT regimens viz. aspirin + clopidogrel (n = 52) (AC group) or aspirin + prasugrel (n = 52) (AP group). Of these, 6 patients in the AC group and 8 patients in the AP group were lost during follow-up; hence, 46 and 44 patients in the two groups, respectively, were included in analysis. At baseline, both the groups were comparable with respect to demographic profile, clinical, and biochemical characteristics [Table 1].

Table 1.

Comparison of baseline demographic, clinical, and biochemical characteristics in two study groups

Characteristic	AC group (n=46)	AP group (n=44)	P
Age (years), mean±SD	51.4±8.7	48.7±9.4	0.36
Males, n (%)	37 (80.4)	34 (77.2)	>0.99
BMI (kg/m2), mean±SD	29.04±4.19	31.02±4.27	0.15
CVD risk factors, n (%)
Diabetes	31 (67.39)	28 (63.63)	>0.99
Hypertension	21 (45.65)	16 (36.36)	0.54
Current smoker	28 (60.86)	25 (56.82)	>0.99
Current alcoholic	30 (65.21)	23 (52.27)	0.31
Family history of CVD, n (%)	18 (39.13)	17 (38.63)	>0.99
Diagnosis, n (%)
STEMI	20 (43.5)	23 (52.3)	0.43
NSTEMI	11 (23.9)	10 (22.7)	>0.99
Unstable angina	15 (32.6)	11 (25)	0.51
Hemogram, mean±SD
Hemoglobin (g/dl)	12.97±2.15	12.70±2.46	0.55
PCV (%)	39.44±7.80	38.90±7.64	0.72
Total RBC count (million/ml)	1.69±0.54	4.37±0.66	<0.001
MCV (fL)	91.01±10.66	87.82±16.56	0.24
MCHC (g/dL)	31.42±3.87	34.82±7.11	0.003
Platelet count (Lakh/mm3)	2.27±0.74	2.63±0.75	0.01
hs-CRP (mg/L), median (IQR)	11.27 (7.12)	12.45 (7.95)	0.06
TAOC (µmol/L), median (IQR)	293.19 (113.02)	355.11 (150.02)	0.07

CVD=Cardiovascular disease, STEMI=ST segment elevation myocardial infarction, NSTEMI=Non-STEMI, MCV=Mean corpuscular volume, MCHC=Mean corpuscular hemoglobin concentration, PCV=Packed cell volume, BMI=Body mass index, SD=Standard deviation, AC=Aspirin + clopidogrel, IQR=Interquartile range, AP=Aspirin + prasugrel, hs-CRP=High-sensitivity C-reactive protein, TAOC=Total antioxidant capacity, RBC=Red blood cell

Both the groups showed a reduction in hs-CRP levels from baseline to 4 weeks; however, the reduction in AP group was significantly greater compared to the AC group (median [IQR]: −6.85 [7.5] mg/L in the AP group versus − 4.65 [4.74] mg/L in the AC group; P: 0.002) [Figure 1]. There was improvement in TAOC levels at 4 weeks compared to baseline in both the groups (median [IQR]: 129.39 [381.29] µmol/L in the AP group versus 157.64 [254.23] µmol/L in the AC group), though the difference between the two groups was not statistically significant (P: 0.117) [Figure 2]. No statistically significant difference in change in hemoglobin levels (P = 0.69) and PCV (P = 0.65) was observed between two groups.

Figure 1.

Change in high-sensitivity C-reactive protein levels at 4 weeks from baseline in two groups

Figure 2.

Change in total antioxidant capacity levels at 4 weeks from baseline in two groups

A total of 20 and 21 adverse events were reported in the AC and AP groups, respectively. Two (4.3%) patients in the AC group and 4 (9%) patients in the AP group had bleeding episodes of easy bruising and bleeding from gums; all the events were categorized as type 1 (minimal bleeding, not actionable) according to the BARC classification. Other commonly reported adverse events were headache, fatigue, weakness, itching, dyspepsia, nausea, vomiting etc. [Table 2]. All the adverse events were mild in intensity, transient, and spontaneously resolved without warranting any active intervention or treatment withdrawal/discontinuation. Medication adherence was assessed by patient self-reporting during follow-up visits and telephonic interviews during the 4-week period. Patients missing more than 20% of prescribed doses were considered nonadherent. Adherence to study interventions was more than 80% in both the groups.

Table 2.

Comparison of bleeding and other adverse events in two study groups

Adverse event	AC group (n=46), n (%)	AP group (n=44), n (%)	P
Bleeding	0	1 (2.27)	0.48
Easy bruising	2 (4.35)	3 (6.81)	0.67
Chest pain	0	0	>0.99
Dyspnoea	0	1 (2.27)	0.48
Palpitation	0	0	>0.99
Numbness of limbs	0	0	>0.99
Slurred speech	0	0	>0.99
Cough	0	0	>0.99
Headache	3 (6.52)	2 (4.54)	0.68
Nausea/vomiting	2 (4.35)	1 (2.27)	0.58
Dizziness	1 (2.17)	2 (4.54)	0.53
Fatigue/weakness	3 (6.52)	1 (2.27)	0.61
Constipation	0	0	>0.99
Diarrhea	1 (2.17)	1 (2.27)	0.97
Indigestion	1 (2.17)	0	0.32
Abdominal pain	1 (2.17)	1 (2.27)	0.97
Muscle pain	0	0	>0.99
Sleep problems	0	1 (2.27)	0.30
Itching	2 (4.35)	2 (4.54)	0.96
Epigastric pain	0	1 (2.27)	0.30
Lightheadedness	1 (2.17)	0	0.32
Swelling in extremities	1 (2.17)	1 (2.27)	0.97
Dyspepsia	1 (2.17)	2 (4.54)	0.53

AP=Aspirin+prasugrel, AC=Aspirin+clopidogrel

Discussion

Given the remarkable role of inflammation and oxidative stress in the pathogenesis and disease progression in ACS and to build on the existent knowledge base, the present study aimed to rigorously explore the comparative anti-inflammatory and antioxidant effects of clopidogrel versus prasugrel when given as DAPT along with aspirin in ACS patients undergoing PCI.

Both clopidogrel and prasugrel containing DAPT regimens demonstrated decline in hs-CRP levels at 4 weeks from baseline, denoting an effective inflammation control with both the agents, though the reduction was significantly more in the AP compared to the AC group, indicating the greater anti-inflammatory efficacy of prasugrel compared to clopidogrel. Our findings align with a previous study[14] reporting greater reduction in hs-CRP levels with prasugrel compared to clopidogrel. Schnorbus et al.[15] also demonstrated higher anti-inflammatory action and improvement in endothelial function with prasugrel compared to clopidogrel and ticagrelor in similar patient population. Hence, it is evident that prasugrel consistently demonstrates greater anti-inflammatory action than clopidogrel and hence offers auxiliary benefit, especially in patients with escalated inflammatory activity. The anti-inflammatory action of clopidogrel is mainly attributed to stimulation of endothelial nitric oxide synthesis, leading to coronary vasodilation, an effect independent of the drug’s antiplatelet action, indicating its pleiotropic property.[16] Ramadan et al.[17] in a randomized placebo controlled study in patients with stable CAD, however, reported contrasting findings with nonsignificant decrease in hs-CRP levels with clopidogrel therapy over 6 weeks. Such observed discrepancy from our findings may partly be explained by difference in disease characteristics and use of aspirin in the two studies.

Baseline TAOC levels in our study population were comparable to an earlier published study,[18] reporting significantly lower TAOC in ACS patients (533.61 ± 232.47 µmol/L) compared to healthy controls (1091.62 ± 267.27 µmol/L, P < 0.001) highlighting on the depletion of antioxidants in ACS and the escalated oxidative stress experienced by these patients. We observed significant improvement in TAOC at 4 weeks from baseline in both AC and AP groups with a relatively greater increase in TAOC in the prasugrel group, though it was not significant statistically. Our results are in congruence with the study by Schnorbus et al.,[15] in which the authors observed a significant reduction in oxidative stress markers with prasugrel compared to clopidogrel in ACS patients undergoing PCI. On the contrary, Willoughby et al.[19] reported no significant effect of clopidogrel on oxidative stress markers, including asymmetric dimethyl arginine and myeloperoxidase in stable CAD patients; this observed variability could be attributed to differences in study design, particularly the exclusion of high-risk ACS patients in that study. Furthermore, the concurrent use of aspirin in our study could have potentially accentuated the antioxidative effects of dual therapy, underscoring the importance of combination therapy in addressing oxidative stress in ACS. Nevertheless, these observations collectively point toward enhanced antioxidative properties of prasugrel, which may bestow clinical benefits over and above the drug’s potent antiplatelet action in high-risk ACS patients.

We also evaluated the impact of DAPT on key hematological parameters, including hemoglobin levels and PCV after 4 weeks of treatment. Both the groups showed minimal changes in these parameters, indicating that neither combination significantly affected red blood cell indices during the study period. These findings align with existing literature,[14,15,16,17,18,19] suggesting that DAPT, particularly within the short-term follow-up period, does not significantly alter hematological parameters.

Few limitations in the present study are worth mentioning. The study was conducted at a single center limiting the generalizability of the findings to other populations with different demographic and clinical profiles. A relatively short follow-up period of 4 weeks limits the ability to assess the long-term effects of DAPT on inflammatory and oxidative stress markers. Variability in patient characteristics, such as genetic factors influencing drug metabolism (e. g., cytochrome CYP2C19 polymorphisms affecting clopidogrel efficacy), was not assessed, which may have influenced treatment outcomes. The major strengths of the study include a prospective real-world comparative evaluation of the anti-inflammatory and antioxidant potential of clopidogrel- and prasugrel-based DAPT, objective assessment of inflammatory and oxidative stress biomarkers, and standardized evaluation of bleeding events using the BARC classification.

Conclusions

In the present study, significantly greater reduction in inflammatory markers was reported in the AP group compared to the AC group, whereas the improvement in oxidative stress parameters, though numerically higher in AP group, did not reach statistical significance. No significant differences were observed between the two groups with respect to hematological safety or tolerability. These findings provide preliminary evidence regarding additional pleiotropic benefits offered by prasugrel-based DAPT, particularly in managing inflammation and oxidative stress in patients with ACS undergoing PCI. There is a need of large-scale, randomized, controlled studies to confirm these findings and further investigate the long-term pleiotropic effects of these antiplatelet agents.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

This research was partially funded by the Research and Development Cell, University of Health Sciences, Rohtak, under Postgraduate Dissertation Scheme.