Letter to the Editor: Methodology vs reality - deciphering cardiovascular safety of proton pump inhibitors in dual antiplatelet therapy

Abstract

Dual antiplatelet therapy (DAPT) is a cornerstone of secondary ischemic prevention following percutaneous coronary intervention. However, DAPT increases the risk of major gastrointestinal bleeding. To mitigate this complication, guidelines suggest prescription of proton pump inhibitors (PPIs) for patients with high-risk profile. The combination of PPI and DAPT has raised concerns because of the risk of drug-drug interaction potentially reducing clopidogrel efficacy and increasing ischemic risk. Randomized controlled trials (RCTs) and observational studies conducted in past years yielded conflicting results. A recent comprehensive meta-analysis recently published in World Journal of Cardiology by Sohail et al evaluated the cardiovascular safety of PPIs in patients with acute coronary syndromes treated with percutaneous coronary intervention and DAPT, including both RCTs and real-world observational studies. By analyzing RCT data independently from observational retrospective cohorts the authors of this meta-analysis successfully untangled the conflicting outcomes and demonstrated that PPI use did not translate into any significant increase in hard cardiovascular endpoints, including acute coronary syndromes, stent thrombosis, all-cause mortality, or cardiac death.

Key Words: Proton pump inhibitors; Clopidogrel; Drug-drug interaction; Dual antiplatelet therapy; Percutaneous coronary intervention

Core Tip: The combination of proton pump inhibitor and dual antiplatelet therapy, in patients undergoing percutaneous coronary intervention, has raised concerns because of the risk of drug-drug interaction potentially reducing clopidogrel efficacy and increasing ischemic risk. A recent meta-analysis, by methodically isolating randomized data from observational biases, proved that the increased cardiovascular risk seen in prior literature was a product of patient-level confounding rather than true biological harm and provided reassurance regarding the safety of combining proton pump inhibitors with clopidogrel.

TO THE EDITOR

Dual antiplatelet therapy (DAPT), combining aspirin and a P2Y12 receptor inhibitor like clopidogrel, remains a cornerstone of secondary ischemic prevention following percutaneous coronary intervention (PCI)[1,2]. However, the therapeutic benefits of intensive antiplatelet regimens are inherently offset by a heightened risk of major gastrointestinal bleeding, especially involving upper tract[3,4]. To mitigate this complication, international clinical guidelines actively endorse the prophylactic co-prescription of proton pump inhibitors (PPIs) for patients with high-risk profile (older age, peptic ulcer disease, concomitant use of anticoagulants or corticosteroids)[4]. Despite its clinical prevalence, this pharmacological combination has sparked a decade-long controversy. Mechanistic concerns primarily highlight a competitive drug-drug interaction, wherein certain PPIs inhibit the cytochrome P450 enzyme CYP2C19, potentially lessening clopidogrel biotransformation and escalating ischemic risks[4]. In a recent issue of the World Journal of Cardiology, Sohail et al[5] addressed this issue through a comprehensive meta-analysis evaluating the cardiovascular safety of PPIs in patients with acute coronary syndromes (ACS) treated with PCI and DAPT (aspirin plus clopidogrel). This meta-analysis included 9 studies, 4 randomized controlled trials (RCTs) and 5 retrospective observational studies, with a total of 12586 patients, 40% receiving PPIs and 60% without PPI therapy. By stratifying evidence between RCTs and real-world observational studies, their work provides an essential framework for contextualizing discordant clinical data and separating theoretical pharmacological harm from actual adverse outcomes.

CRITICAL ANALYSIS OF METHODOLOGICAL DICHOTOMY AND STRENGTHS

The primary clinical asset of the study by Sohail et al[5] lies in its methodological decision to analyze RCT data independently from observational retrospective cohorts. This clear stratification successfully untangles the conflicting outcomes that have long-pervaded existing cardiology literature. When pooling randomized data, the authors demonstrated that concomitant PPI use does not translate into any significant increase in hard cardiovascular endpoints, including ACS, stent thrombosis, all-cause mortality, or cardiac death. This core finding directly supports the milestone conclusions of the COGENT trial[6] (which remains the key randomized standard for this specific drug combination) and also confirms the results of subsequent studies[7-10].

Conversely, when Sohail et al[5] synthesized data from the five included observational studies, a statistically significant 29% increase in major adverse cardiovascular events became apparent. Rather than interpreting this signal as clinically significant, the authors considered it as an artifact of residual confounding and prescription bias. In unblinded clinical environments, PPIs are selectively prescribed to older, sicker individuals who present with severe cardiovascular comorbidities, baseline frailty, and elevated bleeding tendencies. Consequently, the higher major adverse cardiovascular events rate observed in observational cohorts reflects the baseline risk profile of the patient population rather than a chemical failure of the antiplatelet drug interaction. By confirming that risks do not increase for hard, specific ischemic endpoints like stent thrombosis across both study types, this meta-analysis effectively minimizes long-standing fears regarding compromised clopidogrel efficacy.

LIMITATIONS AND NUANCES IN PHARMACOKINETICS

While the meta-analysis offers solid clinical clarity, several inherent limitations must be addressed to appropriately apply these findings to bedside decisions. First, a major constraint is the lack of patient-level data regarding the specific types and dosages of the prescribed PPIs, because the meta-analysis did not provide agent-specific information. From a pharmacokinetic standpoint, PPIs are not interchangeable. Molecules like omeprazole and esomeprazole are potent, competitive inhibitors of the CYP2C19 pathway, whereas lansoprazole, pantoprazole and rabeprazole exhibit a much weaker inhibitory profile[11-13]. By pooling non-selective PPI cohorts with specific pantoprazole or omeprazole arms, the analysis inadvertently dilutes the distinct genetic and metabolic hazards linked to stronger CYP2C19 inhibitors.

Second, the paper evaluated patients treated with aspirin and clopidogrel, so it lacks a detailed subgroup evaluation regarding the specific generation of P2Y12 inhibitors utilized. Although clopidogrel relies heavily on CYP2C19 metabolism, newer antiplatelet agents, such as ticagrelor and prasugrel, bypass this metabolic step entirely and are largely unaffected by concurrent PPI therapy[11]. In current clinical practices many ACS patients are treated with more potent antiplatelets agents (ticagrelor and prasugrel) so interaction with PPIs is not an issue in this case. However, clopidogrel still today remains widely prescribed, particularly among elderly patients, patients at high bleeding risk, those receiving concomitant oral anticoagulation, and patients undergoing elective PCI in stable coronary artery disease.

Third, the paper by Sohail et al[5] focused only on patients with ACS (although the studies in their meta-analysis also included stable patients), so the conclusions cannot be generalized to the entire population undergoing PCI.

Lastly, the short follow-up periods across the majority of the included trials - frequently limited to 12 months or less - restrict our understanding of long-term cardiovascular safety and the durability of gastroprotective therapy beyond the initial high-risk post-PCI window.

FUTURE HORIZONS AND CLINICAL RECOMMENDATIONS

Moving forward, the cardiology community must transition away from broad class-effect debates and focus on precise, patient-centered stratification. Future prospective investigations should integrate baseline genetic screening for CYP2C19 loss-of-function alleles for patients receiving clopidogrel and PPI therapy[14,15]. This approach would identify the specific subpopulation that may face true ischemic risks from strong competitive inhibitors like omeprazole. Furthermore, large-scale registries are required to investigate the long-term clinical interplay of PPIs with newer, potent antiplatelet therapies in real-world settings.

From a practical perspective, the findings by Sohail et al[5] reinforce a clear clinical message: Gastroprotective therapy should not be withheld from patients with valid guideline indications. The threat of gastrointestinal bleeding represents a concrete, highly morbid clinical event that significantly undermines patient compliance and long-term survival. To optimize safety, clinicians should adopt a personalized strategy. For patients requiring clopidogrel who present with high gastrointestinal bleeding risks, it is prudent to prescribe a PPI with minimal CYP2C19 inhibition, such as pantoprazole, thereby preserving antiplatelet efficacy while securing robust gastric protection[3,8,11].

Another important and practical clinical issue to consider, when prescribing PPI therapy in patients receiving DAPT with clopidogrel, is the role of aspirin. The reduced metabolic activation of clopidogrel and blunted platelet-inhibitory response are not observed in the presence of concomitant aspirin, suggesting that aspirin co-therapy may attenuate the potential inhibitory effect of PPIs on clopidogrel[16]. With the growing evidence favoring shorter DAPT, P2Y12 inhibitor monotherapy will be increasingly used for secondary prevention shortly after PCI. The clinical impact of concomitant PPI use during clopidogrel monotherapy is currently unknown and should be evaluated in future studies.

CONCLUSION

In conclusion, the meta-analysis by Sohail et al[5] provides reassurance regarding the safety of combining PPIs with DAPT after a PCI. By methodically isolating randomized data from observational biases, the study suggests that the elevated cardiovascular risk seen in prior literature is a product of patient-level confounding rather than true biological effect. While pharmacokinetic differences among individual PPIs require careful clinical selection, the routine, guideline-compliant use of gastroprotection remains a safe and necessary practice to achieve balanced ischemic and bleeding outcomes in post-PCI patients.