This tendency was associated with misuse and overuse of antibiotics, and increased laboratory testing, such as blood cultures, which had to be obtained before antibiotics were initiated. The authors emphasized the importance of reimbursement-associated quality measures creating incentives to treat the right patients for the correct diagnosis, and the potential harmful consequences of applying a quality-driven protocol to the wrong patient.

They suggest a six-hour rule would decrease the misdiagnosis of CAP. They also feel eliminating a mandatory time frame and requiring only that the first dose of antibiotics be administered in the ED will further ameliorate these effects.

Bottom line: Mandatory administration of antibiotics to patients with suspected CAP within four hours of triage increases the percentage of patients who receive antibiotics within four hours, but also increases the rate of misdiagnosis of CAP, inappropriate administration of antibiotics, and increased use of some laboratory services.

Citation: Kanwar M, Brar N, Khatib R, et al. Misdiagnosis of community-acquired pneumonia and inappropriate utilization of antibiotics: side effects of the 4-hour antibiotic administration rule. Chest. 2007 Jun;131(6):1865-1869.

Does prophylactic cardiac revascularization benefit patients undergoing vascular surgery?

Background: American College of Cardiology/American Heart Association Guidelines recommend referral for patients with multiple cardiac risk factors for non-invasive cardiac stress testing prior to surgery and prophylactic revascularization in high-risk patients. The authors performed a pilot analysis to determine how many patients would be needed to prospectively validate this recommendation in those with more significant ischemic cardiac disease.

Study design: Randomized controlled pilot study of 1,880 consecutive patients undergoing elective vascular surgery

Setting: Brazil, Belgium, the Netherlands, Italy, Serbia, and Montenegro

Synopsis: This was a pilot study to determine the necessary power to prove or disprove the benefit of the recommendation for cardiac revascularization in high-risk patients before major vascular surgery.

Prior research had shown that prophylactic revascularization is not of demonstrable benefit in this cohort. However, the majority of the patients in this previous trial had two-vessel disease and preserved left ventricular function. This study examined a sicker cohort of patients with more significant coronary artery disease and depressed left ventricular function.

This pilot screened all patients undergoing high-risk vascular surgery. All patients with three or more risk factors underwent non-invasive evaluation for cardiac ischemia. Patients with extensive ischemia were randomized to invasive evaluation and revascularization as appropriate or non-invasive management. Both arms received optimal medical management.

Prophylactic revascularization did not improve 30-day outcome after vascular surgery, demonstrated no difference in perioperative cardiac events, and found no difference in all-cause mortality or nonfatal myocardial infarction. Similarly, there was no evidence of long-term (at one year) difference between groups. The sample size needed to definitively establish that coronary revascularization is superior to medical therapy would be 300 patients per arm. That would require screening 9,000 patients.

Bottom line: Prophylactic revascularization has no clear benefit for high-risk patients undergoing vascular surgery, but a much larger sample size would be required to definitively prove or disprove benefit.

Citation: Poldermans D, Schouten O, Vidakovic R, et al. Clinical randomized trial to evaluate the safety of a noninvasive approach in high-risk patients undergoing major vascular surgery: the DECREASE-V pilot study. J. Am Coll Cardiol. 2007;49(17):1763-1769.

How Does Aspirin Resistance Affect Patients with Coronary Artery Disease?

Background: Although aspirin is used to decrease the risk of ischemic events, up to 45% of patients do not derive adequate anti-platelet activity. Few prospective studies have used laboratory-measured aspirin resistance to assess clinical outcomes.

Study design: Blinded cohort

Setting: Patients affiliated with Queen Mary Hospital, the University of Hong Kong.