Infection After Primary PCI Rare but Serious

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Only a minority of patients with ST-segment elevation myocardial infarction (STEMI) develop infections after undergoing primary percutaneous coronary intervention (PCI). But when such complications do occur, they are associated with a sharp fivefold increase in the risk of death or myocardial infarction (MI), according to a subanalysis of a randomized trial published online July 16, 2012, in JACC: Cardiovascular Interventions.

Researchers led by Renato D. Lopes, MD, PhD, of the Duke Clinical Research Institute (Durham, NC), reviewed data on infections among 5,745 STEMI patients who had enrolled in the APEX-AMI (Assessment of Pexelizumab in Acute Myocardial Infarction) trial. The study, which randomized patients to adjunctive pexelizumab or placebo in conjunction with primary PCI, was stopped early in 2006 when the anti-inflammatory agent failed to improve outcomes. Main results were published in the Journal of the American Medical Association in January 2007.

Most Infections Happen Past 48 Hours

Overall, 2.4% of patients in APEX-AMI developed a serious infection after primary PCI (median time to diagnosis of 3 days). The majority of infections occurred within 8 days of hospital admission (80%). But only 30.4% of affected patients developed their infection within 48 hours of admission. Most patients (77.5%) had just 1 infection, though nearly one-fifth (18.1%) had 2 and 1 (0.7%) developed a total of 5. Most infections (40.6%) occurred in the blood. A variety of organisms were responsible, with Staphylococcus aureus being the most common at 9.4%.

Rates of death, congestive heart failure, shock, MI, and stroke all were higher in patients who developed infections. Multivariable analysis found serious infection to independently predict 90-day risk of death and the composite of death or MI (table 1). The associations persisted after excluding death or MI observed within 24 hours, and results were similar for patients regardless of whether their infections developed before or after 48 hours.

Table 1. Effect of Serious Infection on 90-Day Outcomes

 

 

Adjusted HR

95% CI

P Value

Death

5.3

3.5-7.8

≤ 0.001

Death or MI

4.6

3.2-6.6

≤ 0.001


In addition, infected patients were more likely to be readmitted within 90 days for another serious infection than were patients who remained free of infection during the index hospitalization (5.1% vs. 0.7%).

Vigilance Required to Spot Early Signs

“Our findings illustrate the importance of serious infection as a marker of worse subsequent clinical outcomes in patients with STEMI treated with primary PCI,” Dr. Lopes and colleagues write, noting that the paper also speaks to how infection should be used as a measure of quality in patient care. New infections occurring at least 48 hours after admission are generally thought to be hospital-acquired, they report. However, applying this cutoff in the current study revealed no differences in 90-day outcomes based on when infections developed.

“These results highlight the importance of identifying patients who are at risk for infection after PCI for STEMI as well as seeking effective strategies for prevention, both to improve clinical outcomes and to reduce resource use,” the investigators conclude. “In addition, vigilance for early diagnosis and treatment of those who develop infection is essential to minimize serious complications.”

In particular, a fever observed more than 24 hours after presentation “might not be due to infarct size or systemic inflammatory response to the infarction but rather might be an early sign of serious infection,” they advise.

Study Details

Baseline characteristics differed widely between patients who did and did not develop serious infections. Patients with infections were significantly older and had more comorbidities including diabetes and congestive heart failure. During hospitalization, they were less likely to receive medications including statins, aspirin, ACE inhibitors, and beta-blockers. Infected patients were also more likely to have complicated procedures that involved intra-aortic balloon pump use, mechanical ventilation, and red blood cell transfusion and to eventually require CABG.

In-hospital complications such as recurrent ischemia and atrial fibrillation were numerically higher in patients who had infections.

 

 


Source:

Truffa AM, Granger CB, White KR, et al. Serious infection after acute myocardial infarction: incidence, clinical features, and outcomes. J Am Coll Cardiol Intv. 2012;5(7):769-776.

 

 

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Infection After Primary PCI Rare but Serious

Only a minority of patients with ST-segment elevation myocardial infarction (STEMI) develop infections after undergoing primary percutaneous coronary intervention (PCI). But when such complications do occur, they are associated with a sharp
Disclosures
  • The APEX-AMI trial was jointly funded by Alexion Pharmaceuticals and Procter & Gamble Pharmaceuticals, and the current analysis received support from the Duke Clinical Research Institute.
  • Dr. Lopes reports receiving a research grant from Bristol-Myers Squibb.

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