Soon after the publication of the New England Journal paper by Brenda Hemmelgarn and
colleagues we had a journal club at the Brigham. Several of the
heavy-weights on the faculty and some of our top fellows opined on the study. I
did too. I was impressed. My conclusion: this study will change clinical
practice. I bet lunch on it. And, sure enough a year later I had lost the bet -
the study hadn't changed practice at all.
Recall the study:
An RCT - 225 patients on chronic HD
with a central venous catheter for access were randomly assigned to a
catheter-locking regimen of heparin (5000 U per milliliter) three times per
week or recombinant tissue plasminogen activator (rt-PA) (1 mg in each lumen)
substituted for heparin at the midweek session (with heparin used in the other
two sessions).
The primary outcome was catheter
malfunction, and the secondary outcome was catheter-related bacteremia. The
treatment period was 6 months; treatment assignments were concealed from the
patients, investigators, and trial personnel.
A catheter malfunction occurred
in 40 of the 115 patients assigned to heparin only (34.8%) and 22 of the 110
patients assigned to rt-PA (20.0%) — an increase in the risk of catheter
malfunction by a factor of almost 2 among patients treated with heparin only as
compared with those treated with rt-PA once weekly (hazard ratio, 1.91; 95%
confidence interval [CI], 1.13 to 3.22; P=0.02).
Where are we on catheter locks nearly 3 years later?
Niyyar and Lok have a nice article in CONH - the November issue - that is a definite read.
Here is their bottom-line:
"Antithrombotic lock solutions may improve patency and CRB but may be cost-prohibitive. Antimicrobial lock solutions may decrease the incidence of CRB, but their routine use is concerning for the risk of systemic toxicity and the development of resistant organisms. Preliminary results suggest a novel antimicrobial and antithrombotic lock solution may be promising in maintaining patency, while decreasing catheter-related bacteremia..... The search is on for the perfect ‘solution’ and though there have been remarkable advances in recent years, the field is still wide open for future innovation."
