Blinklist
delicious
Digg
Facebook
Furl
Google
LinkedIn
ma.gnolia
Mixx
Reddit
Stumbleupon
Twitter
Y! Bookmarks
Yahoo Buzz
Dallas, TX - Physicians treating people with pacemakers or other implanted cardiac devices who also develop Staphylococcus aureus infections should be keenly suspicious that the device will become infected, even if the bacteria was not introduced by the device implantation itself. Such were the conclusions of a new study appearing in the August 28, 2001 issue of Circulation.1
"These results suggest that clinicians caring for patients with permanent cardiac devices who develop SAB [Staphylococcus aureus bacteremia] should have a high index of suspicion that the implant is infected, even if local signs of generator pocket infection are absent and no generator wire or valvular vegetations are detected by TEE [transesophageal echocardiograms]," the authors write.
Dr Anna Lisa Chamis et al (Duke University Medical Center, Durham, NC) note that the risk of developing cardiac device infection (CDI) after S aureus is "inadequately defined," and that physicians often have a hard time figuring out whether a device has become infected.
Almost half of devices infected in SAB+ patients
Now, in a prospective study of 33 patients with cardiac devices who developed SAB, Chamis et al believe they have shed some light on the incidence of CDI with these bacteria.
Over a 6-year period at Duke University Medical Center, Chamis and colleagues found an overall incidence of 15 infected devices out of 33 cases of SAB in treated patients who also had either a pacemaker or ICD. CDI was confirmed in 9 or 12 patients who developed SAB within 1 year of device implantation, and in 15 of 21 patients who developed SAB after the 1-year mark. Of note, out of 15 cases in which CDI was confirmed, 9 showed no local signs or symptoms pointing to generator pocket infection.
Discussing the study with heartwire, senior author Dr Vance G Fowler (Duke University Medical Center, Durham, NC) pointed out that looking at infections developing before or after the 1-year mark provided an "arbitrary line in the sand" in terms of considering device infections that did not become infected during the implantation process.
"In the present study, the incidence of confirmed CDI acquired via hematogenous spread was also high (27.3%)," Chamis et al write.
A particularly bad scenario
"S aureus bacteremia is associated with a high mortality rate despite all important advances and diagnoses and treatments," Fowler explained to heartwire. "SAB in the setting of a prosthetic device, including a pacemaker or implantable defibrillator, is a particularly bad disease and should heighten the clinician's index of suspicion for involvement of the prosthetic device." He also emphasized that the issue should not be blown out of proportion: there were only 33 cases of SAB in people with either pacemakers or ICDs over almost a 7-year period.
If you have staph in your blood and a pacemaker in your body, you need to be worried that the pacemaker may be infected.
Nevertheless, Fowler continued, more and more people are having pacemakers and ICDs implanted, and therefore the numbers of people with devices who also get staph infections may rise over time. "The message that we're trying to get across is that if you have staph in your blood and a pacemaker in your body, you need to be worried that the pacemaker may be infected, even if there aren't clinical signs and symptoms that suggest that the pacemaker is infected," said Fowler. "It's easy when you see pus pouring out of the pacemaker pocket, but you should still think about it and have it on your differential diagnosis. It needs to be one of the things that you're worried about."
The high rate of device infection in patients with SAB warrants "systematic extraction of cardiac devices among most patients who develop SAB, both with and without clear device involvement, as long as skilled transvenous extraction is available to the patient," the authors conclude.
In Fowler's words: "If the device is infected, you really can't eradicate the infection without eradicating the device."
