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The use of automated contrast injector systems during percutaneous coronary intervention (PCI) does not appear to curb kidney damage compared with manual injection, according to an analysis published online March 20, 2013, ahead of print in JACC: Cardiovascular Interventions. The lack of effect is seen despite a significant reduction in contrast volume.

Researchers led by Hitinder S. Gurm, MD, of the University of Michigan (Ann Arbor, MI), assessed data from the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) registry from 60,884 patients who underwent PCI at 28 centers in Michigan from 2008 to 2009. Only 4 of the hospitals (n = 9,995 patients) employed automated injection, while the remaining 24 (n = 50,889 patients) relied on manual injection.

Though PCI cases with automated injection did use less contrast media, patients derived no protection against contrast-induced nephropathy (defined as ≥ 0.5 mg/dL absolute increase in SCr vs. baseline) or need for dialysis (table 1).

Table 1. Outcomes by Contrast Injection Method

In addition, differences between the groups with regard to in-hospital mortality (P = 0.05) or the need for CABG (P = 0.08) just missed statistical significance.

Neither multivariate adjustment for baseline differences nor a propensity-matched analysis including 9,600 patients in each cohort changed the lack of association between injection method and nephropathy, in-hospital mortality, or CABG. However, in the matched analysis, patients who underwent PCI using automated injection had a higher incidence of vascular complications (2.63% vs. 1.84%; P = 0.0002).

Patients who underwent PCI with automated injection were slightly younger, less likely to be hypertensive, and more likely to recently have had an MI. Such procedures involved shorter fluoroscopy time than those using manual injection.

Other Benefits to Automated Systems?

Despite the lack of benefit in terms of CIN reduction, Dr. Gurm told TCTMD in an e-mail communication that there are “other advantages” to automated systems. “They allow use of smaller catheters, . . . and there is less overall use of contrast media (but not necessarily contrast administered to a patient),” he said. Dr. Gurm stressed, however, that the current study shows that the difference in volume for an individual patient is clinically “meaningless.”

Peter A. McCullough, MD, MPH, of St. John Providence Health System (Warren, MI), expressed surprise that the device had no clinical benefit over manual injection. However, in an e-mail communication with TCTMD, he noted some issues with the automated approach. “The device is cumbersome and costly. It also adds set-up time to the procedure,” he said. “I think this paper helps dispel the myth [that automated injection helps] and provides a reason for one less device to clutter up the cath lab.”

Richard Solomon, MD, of the University of Vermont (Burlington, VT), pointed out that the automated injection technology could help relieve hand cramps for operators as well as reduce radiation exposure by allowing them to move behind a lead screen while performing the injection.

Dr. Gurm also stressed that there are other ways physicians can reduce the amount of contrast when automated systems are not available. “Often we will use dilute contrast injections . . . and are routinely able to perform cath or PCI with ultra-low-volume contrast media,” he said. “There are other measures that are equally important, such as making sure a patient is well hydrated prior to the procedure and is on a statin before they get exposed to contrast media.”

Source:

Gurm HS, Smith D, Share D, et al. Impact of automated contrast injector systems on contrast use and contrast-associated complications in patients undergoing percutaneous coronary interventions. J Am Coll Cardiol Intv. 2013;Epub ahead of print.

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