In This Edition
Literature At A Glance
A guide to this month’s studies
- Procalcitonin to guide antimicrobial use in ICU patients
- Platelet reactivity and event rates after PCI
- Conservative treatment of necrotizing pancreatitis
- Use of MRI to diagnose Takotsubo cardiomyopathy
- Rates of inadvertent medication discontinuation after hospitalization
- Role of history and physical exam in diagnosing medical illness
- Red-cell distribution width and rates of mortality
Procalcitonin-Guided Therapy Decreases Antimicrobial Duration in ICU Patients
Clinical question: Can utilization of serum procalcitonin (PCT) levels safely reduce antimicrobial exposure in ICU patients?
Background: Serum PCT levels are elevated in bacterial infections and sepsis and have been used in some settings to guide antimicrobial therapy. Randomized controlled trials have demonstrated reduction of antibiotic use with PCT measurement. This systematic review assessed the safety and effectiveness of PCT measurements in reducing antimicrobial exposure in ICU patients.
Study design: Systematic review.
Setting: Adult medical and surgical ICUs.
Synopsis: A search of MEDLINE and EMBASE yielded 1,018 publications related to PCT, critically ill patients, and antimicrobial therapy. Six randomized controlled trials involving 1,476 patients were reviewed. The duration of antimicrobial use was significantly decreased in all five studies that evaluated treatment duration. The remaining study only assessed the impact of PCT on initiation of antimicrobial therapy and did not demonstrate decreased antimicrobial exposure. Compared with the control group, patients randomized to PCT-guided therapy had relative reductions in duration of first antibiotic course by 21%, down to 38%, and decreases in days of antimicrobial therapy per 1,000 ICU patient days by 20%, down to 23%. PCT intervention also was associated with a 23% to 37% increase in days alive without antimicrobial therapy during the first 28 days. The length of ICU stay was significantly decreased in two studies but was not significantly different in the other studies. There were no significant differences in rates of mortality, infection relapse, or days free of mechanical ventilation.
Bottom line: PCT guidance reduced antimicrobial exposure of ICU patients without increasing rates of mortality or infection relapse.
Citation: Agarwal R, Schwartz DN. Procalcitonin to guide duration of antimicrobial therapy in intensive care units: a systematic review. Clin Infect Dis. 2011;53:379-387.
High Residual Platelet Reactivity Increases Risk of Cardiovascular Events among Patients with Acute Coronary Syndromes Undergoing PCI
Clinical question: Is high residual platelet reactivity (HRPR) in patients receiving clopidogrel associated with increased risk of ischemic events after percutaneous coronary intervention (PCI)?
Background: Studies have demonstrated an increased risk of cardiovascular events associated with HRPR in patients receiving clopidogrel while undergoing PCI. However, these studies have used a variety of platelet function tests, and thresholds for positive tests have not been established. In addition, these studies have enrolled heterogeneous populations with short-term follow-up and few have included patients with acute coronary syndromes (ACSs).
Study design: Prospective cohort study.
Setting: Cardiology service of a referral center in Italy.
Synopsis: This study included 1,789 consecutive patients with ACS undergoing PCI. Patients were given 325 mg aspirin and a 600-mg loading dose of clopidogrel on admission, followed by a daily maintenance dose of aspirin 325 mg and clopidogrel 75 mg for at least six months. Platelet reactivity was measured using adenosine diphosphate (ADP) testing, and those with HRPR (≥70% platelet aggregation) were given increased dosing of clopidogrel or switched to ticlopidine using ADP test guidance. At two-year follow-up, patients with HRPR experienced an increased composite endpoint of cardiac death, myocardial infarction, urgent coronary revascularization, and stroke with a combined event rate of 14.6% in patients with HRPR and 8.7% in patients with low residual platelet reactivity (95% CI, 1.6%-11.1%; P=0.003). Stent thrombosis was also higher in HRPR patients (absolute risk increase 3.2%; 95% CI, 0.4%-6.7%; P=0.01).