Failure to Give Pre-PCI Aspirin Not Infrequent Cause of Complications

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A sizeable number of patients fail to receive aspirin before undergoing percutaneous coronary intervention (PCI), according to a large registry study published online October 2, 2013, ahead of print in the Journal of the American College of Cardiology. Because the practice leads to higher risk of in-hospital death and stroke, quality improvement efforts should focus on optimizing aspirin use in this context, researchers say.

The findings were previously presented at the 2013 American College of Cardiology Annual Scientific Session in San Francisco, CA.

Hitinder S. Gurm, MD, of the University of Michigan (Ann Arbor, MI), and colleagues analyzed data from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) registry on 65,175 PCI patients treated at 42 hospitals in Michigan from 2010 to 2011.

Within that population, 4,640 patients (7.1%) did not receive aspirin within 24 hours prior to PCI. Only 495 patients (10.7%) within this group had a documented contraindication. Nearly half of patients who did not receive aspirin before PCI (45.5%) were started on aspirin after the procedure.

In-Hospital Death, Stroke Higher Without Aspirin

Presenting diagnoses in the nonaspirin group were NSTEMI/unstable angina (40.2%), stable CAD (31.2%), and STEMI (17.9%); the remaining patients underwent PCI for other indications. Numerous baseline characteristics differed between the aspirin and nonaspirin groups; for example, patients not given aspirin were more likely to be male, have a history of GI bleeding and to present with STEMI, in cardiogenic shock, or after cardiac arrest compared with those who received the drug. They also were less likely to have hypertension or a history of PCI.

In-hospital outcomes including death and stroke were poorer among patients not given aspirin, though rates of postprocedural MI, emergent CABG, repeat PCI at the same lesion, and vascular complications did not differ (table 1).

Table 1. Unadjusted In-Hospital Outcomes

In propensity score-matched analysis of 8,016 patients, omission of pre-PCI aspirin was associated with increased risk of death (3.9% vs. 2.8%; OR 1.89; 95% CI 1.32-2.71; P = 0.005) and stroke (0.5% vs. 0.1%; OR 4.24; 95% CI, 1.49-12.11; P = 0.007). Trends toward higher risk of cardiovascular death and CABG did not reach statistical significance.

If replicated, the results “would justify more focused efforts to optimize aspirin use and shape a strategy to manage patients with true contraindications or intolerances to aspirin therapy including the need for desensitization therapy, consideration of other options for dual antiplatelet therapy or possible surgical revascularization, which would not require aspirin pretreatment,” the investigators conclude.

Aspirin for All?

Dr. Gurm told TCTMD in a telephone interview that he had expected lack of preprocedural aspirin to be “a very rare problem,” given that so few patients suffer from aspirin allergies. “But what shocked me was that 7% of patients were not on aspirin for the procedure,” he said, noting that most did not have true contraindications.

Acknowledging the observational study’s inherent uncertainty over whether the relationship between pre-PCI aspirin and outcomes is causative, Dr. Gurm said, “I don’t think we’ll ever do a randomized study to assess this. So I think our best bet is to [ask] what we can do to minimize risk. As a first step, we need to be aware that this is a common problem, much more so than many physicians think.”

Ensuring that all patients are on aspirin preprocedure is imperative, he advised. “At our institution, we made it part of the ‘time out,’” Dr. Gurm explained. “So [even if] a patient comes in in cardiac arrest or shock, we will always confirm if a patient is on aspirin and if not, why not. If they don’t have a clear anaphylactic reaction or something like that, we’ll load them in the cath lab. Aspirin works very quickly.”

In a telephone interview with TCTMD, Neal S. Kleiman, MD, of Methodist DeBakey Heart and Vascular Center (Houston, TX), said that the phenomenon of poorer outcomes without preprocedural aspirin “is not new,” having been first described in the 1980s. Even so, he noted, “I think it’s important to see that other modern therapies haven’t eliminated the need [for aspirin].”

WOEST Data Cause for Pause

“But there’s also the background that there’s a lot of controversy about aspirin now. It currently is not clearly indicated for primary prevention and maybe not even for secondary prevention,” Dr. Kleiman continued. He said that recent data from the WOEST trial, which show that PCI patients on warfarin may experience less bleeding and no added risk of thrombotic events when receiving clopidogrel alone rather than dual antiplatelet therapy, make him even more cautious.

In the current paper, Dr. Gurm and colleagues emphasize that their study “serves as a reminder not to apply the results of the WOEST study liberally across all patients undergoing PCI.”

As to whether concerns over WOEST might influence practice, Dr. Gurm noted that “none of these things exist in a vacuum. It makes rational people stop and think. . . . There are enough things floating around in the background that I think people are being a little more circumspect about who they give aspirin to.”

In fact, quality improvement efforts may not be justified, he said, given that the number of events prevented would be small even if aspirin were given to all patients without contraindications. “Is it worth investigating in a quality improvement effort to go from 94.5% compliance to 97%? It would have to be an awfully good therapy to do that,” he stressed.

Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), said that the “analysis does support the current clinical practice of administration of aspirin prior to PCI. What is not ascertainable from this database is how soon prior to PCI aspirin needs to be administered.”

Though quality improvement initiatives appear warranted, he told TCTMD in an e-mail communication that “[o]verall, the limitation of these types of analyses is that the effects of residual unmeasured confounding are hard to overcome, despite the authors significant efforts to account for this.”

 

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Source:
Kenaan M, Seth M, Aronow HD, et al. The clinical outcomes of percutaneous coronary intervention performed without pre-procedural aspirin. J Am Coll Cardiol. 2013;Epub ahead of print.

 

 

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• Without Preprocedural Aspirin, PCI Carries Higher Risk of In-Hospital Death, Stroke
• For A-fib Patients, Aspirin on Top of Anticoagulation Raises Bleeding Risk
• WOEST: Clopidogrel Alone Works Best for PCI Patients on Oral Anticoagulants