Anticoagulation Protects A-Fib Patients Undergoing PCI, Despite Bleeding Risk

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Among patients with atrial fibrillation (A-fib) who receive stents, even those at high bleeding risk stand to benefit from oral anticoagulation at discharge. Findings published online July 10, 2012, ahead of print in Circulation: Cardiovascular Interventions, show that reductions in mortality and other adverse events outweigh the negative effects of major bleeding in this population.

Gregory Y. H. Lip, MD, of City Hospital (Birmingham, United Kingdom), and colleagues reviewed details from a prospectively gathered database on 590 patients with A-fib who were implanted with stents over a 7-year period ending in March 2008. All had CHADS₂-VASC scores greater than 1, indicating need for oral anticoagulation. Patients were stratified by HAS-BLED score into groups of low/intermediate bleeding risk (0-2) or high bleeding risk (≥ 3).

Efficacy, Safety Trade-Off

Overall, 28.8% of patients were considered at low/intermediate risk of bleeding and 71.2% at high risk. Slightly more than half of patients received warfarin at discharge, whether they fell into the low/intermediate- (54.1%) or high-risk groups (57.1%).

At 1 year, the low/intermediate-risk patients saw a mortality rate of 7.3% and a MACE (death, acute MI, or TLR) rate of 8.8%. Major bleeding occurred in 5.7% overall; even within this comparatively lower risk group, however, anticoagulant use led to numerically higher bleeding rates (7.8% with vs. 1.6% without anticoagulation; P = 0.13).

The effect on major bleeding at 1 year was significant in the high-risk group, though such patients also experienced reductions in death and MACE with anticoagulation. Considering major bleeding and thromboembolism along with MACE, outcomes were similar regardless of warfarin use (table 1).

Table 1. Subgroup at High Bleeding Risk (HAS-BLED ≥ 3): 1-Year Outcomes

^aMACE, major bleeding, or thromboembolism.

Multivariate analysis confirmed that in patients at high bleeding risk, anticoagulant use at discharge was associated with lower likelihoods of death, MACE, and major adverse events but no longer appeared to increase major bleeding (HR 2.31; 95% CI 0.55-9.71; P = 0.25). Predictors of MACE in the high-risk patients were age (P < 0.01) and congestive heart failure (P = 0.03), while anticoagulation had a protective effect (P < 0.01). Major bleeding, meanwhile, was predicted by chronic renal failure (P < 0.01) and DES use (P = 0.04).

Despite the existence of guidelines addressing anticoagulation in A-fib patients undergoing PCI, “many clinicians often have doubts over how to manage those patients [who have an indication for oral anticoagulation] but are at high bleeding risk,” the authors note, pointing out that their findings show net clinical benefit. Ongoing trials such as ISAR-TRIPLE, WOEST, and MUSICA-2 may provide further information on the best strategy, they say.

Nothing in Isolation

In an e-mail communication, Sunil V. Rao, MD, of Duke University Medical Center (Durham, NC), told TCTMD, “This [study] underscores the complexity of the patients that we are seeing in the cath lab and the [cardiac care unit]. We are used to thinking of cardiovascular problems in isolation, but the reality is that many conditions coexist, and treatments for those conditions result in competing risks.”

In caring for patients “one has to be especially cognizant of the bleeding risks and use strategies to minimize bleeding,” he continued, citing bivalirudin, radial access, and avoidance of potent antiplatelet agents as examples. “In addition, careful attention to stent type and minimizing the duration of triple therapy is also important.”

Knowing how best to decide which patients can derive enough benefit to offset bleeding risk is “the holy grail, and I’m not sure that we have effective tools to do that yet. This is a situation where strategies have to be tailored to the individual patient,” Dr. Rao commented. In such situations, he added, it is even more crucial than usual “to discuss the risks and benefits of PCI with each patient.”

The research conducted by Lip et al “is very important and should lead to more studies to try and individualize risk,” Dr. Rao concluded.

Source:

Ruiz-Nodar JM, Marín F, Roldán V, et al. Should we recommend oral anticoagulation therapy in patients with atrial fibrillation undergoing coronary artery stenting with a high HAS-BLED bleeding risk score? Circ Cardiovasc Interv. 2012;Epub ahead of print.

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