Illuminating Contrast Media Management

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Providers evaluate a number of patient safety considerations before administering contrast media. As automated contrast injectors are increasingly utilized in cardiology departments—replacing the older manifold models—administrators are establishing protocols to lessen the incidence of contrast-associated adverse events, as well as improving the bottom line. Both goals, it seems, are interrelated.

Patient Safety

The risks associated with contrast are well-documented, and primarily include contrast-induced nephropathy (CIN) and nephrogenic systemic fibrosis (NSF). CIN is "extremely low risk" for patients with normal renal function, according to the American College of Radiology (ACR), but for older patients—and those with diabetes or other conditions—the potential is greater. NSF has been correlated with gadolinium-based MRI contrast agents in patients with kidney disease.

Some doctors may be firm about their preferred types of contrast. However, most physicians seem to agree on two methods for reducing risk.

"Dye-load and adequate hydration are the only two things that have been consistently shown to reduce the risk of developing contrast-induced nephropathy," says Jason T. Call, MD, a cardiologist at Winchester Cardiology & Internal Medicine in Winchester, Va.

This opinion is supported by various studies assessing the relationship between contrast and adverse events. Contrast volume is a key risk factor for contrast-induced acute kidney injury (CI-AKI) for patients undergoing PCI, according to Jeremiah R. Brown, PhD, of the Dartmouth Institute for Health Policy & Clinical Practice, Dartmouth Hitchcock Medical Center, in Hanover, N.H., and colleagues. The incremental use of contrast beyond the maximum acceptable contrast dose (MACD)—defined as 5 ml times the body weight [kg]/baseline serum creatinine—is associated with greater risk of adverse events (J Am Coll Cardiol Intv 2009;2(11):116–124).

In their analysis of nearly 10,000 patients prospectively enrolled from 2000 to 2008, researchers found that 20 percent of patient procedures exceeded the MACD.

"Patients exceeding the MACD threshold were more likely to be in shock, have two- or three-vessel disease and left main stenosis, and receive more stents," Brown et al wrote. "Patients receiving contrast volumes in excess of the MACD were more likely to have CI-AKI, new onset of dialysis dependent renal failure, cardiac events, bleeding complications, receive transfusions and have a longer length of stay post-PCI. Importantly, their mortality rates also were higher during PCI admissions." Researchers also found that risk-adjusted CI-AKI increased by an average of 45 percent for each category exceeding the MACD.

Certain patient characteristics indicate greater risk for CIN and baseline kidney. Baseline kidney function and diabetes are the two top variables, Call says. If a patient has one of these variables, risk for CIN may increase to 3 to 5 percent, however if he or she has both variables, the risk that the kidneys will be transiently harmed rises to 10 to 15 percent. Additional risk factors include allergies, asthma, and cardiac status, according to the American College of Radiology.

In some situations, the benefits of imaging a patient outweigh the risks associated with the administration of contrast, says says Hani H. Abujudeh, MD, MBA, director of quality assurance in radiology at Massachusetts General Hospital in Boston. If an alternative diagnostic method can produce the desired information in a high-risk patient—such as ultrasound, CT without contrast or an MRI without contrast—that may be better.

Nevertheless, the potential of kidney problems may be a small price to pay for life-saving information. "If contrast results in a diagnosis of a life-threatening condition, then it outweighs the risk of contrast nephropathy," Abujudeh says.

Call concurs, "If we're treating someone's heart attack, you can't stop. It's a life-saving procedure, and you have to accept the risk."

Automated injectors

Manifold contrast injectors haven't been pushed out to every clinical setting, but hospitals are increasingly adopting automated systems, which have been shown to reduce the amount of contrast and diminish cost. However, in a recent meta-analysis, Brown and colleagues recommend further research on the association between reduced contrast volume and the risk of CIN.

In their meta-analysis of six studies, researchers found that the use of automated contrast injection significantly reduced the volume of contrast delivered to a patient, but there was a lack of evidence regarding the risk of CIN. "Further research is needed to elucidate the effects of reduced contrast volume on CIN," Brown and colleagues wrote. "There was a significant drop in the average contrast used for each case within randomized trials," Brown says. "The evidence is lacking—especially from trials where patients had been randomized through an automated injector or not—on acute kidney injury."

Call and colleagues found that the use of an automated contrast injection system in conjunction with contemporary strategies of hydration during diagnostic catheterization and PCI was associated with a significant reduction in the use of contrast volume, as well as in the incidence of CIN.

Call and colleagues studied the incidence of CIN in 1,798 patients after diagnostic catheterization or PCI at Wake Forest University Baptist Medical Center in Winston-Salem, N.C., from April 2002 to November 2004, using handheld manifold injection systems, and in 377 subsequent patients using an automated contrast injection system (J Invasive Cardiol 2006;18(10):469-74). Pre-procedural hydration was used routinely, according to the study, and N-acetylcysteine and bicarbonate infusion were used on an ad hoc basis.  The incidence of CIN was 19.3 percent using a manifold injection, and 13.3 percent after using an automated contrast injection.

"[A]utomated contrast injection was associated with a reduced risk of CIN, compared with manual injection, even after adjustment for baseline clinical and procedural covariates," the authors wrote.

"Being cognizant that [CIN is] a problem, trying to minimize the volume of contrast during a procedure, making modifications during the case if necessary, while paying attention to adequate hydration status are most important," Call says.

Traditionalists may prefer the old manifold injectors, but most physicians warm up to the new technology, notes Call, who oversaw the transition at Winchester Cardiology. Of about 20 physicians, only two were averse to using the automated systems, perhaps because it's less hands-on, he says, but they eventually came around.

The bottom line

While there are upfront costs with installing automated injectors, they can eventually pay for themselves. When Call oversaw his hospital's implementation, it took roughly 34 months for the decreased use of contrast to pay for five new automated injectors.

Comparing five months in 2003 to five months in 2004, 21 cases of contrast were saved by using the automated injectors, Call reports, which is equivalent to 210 bottles of contrast that were saved over the five-month period. The cost of each machine, at the time, was about $24,000. He says the reduction saved approximately $3,400 per month, or $700 per month for each of the five machines.

Contrast is useful because it helps in the diagnosis of various diseases and conditions. Injecting less contrast saves money. But it's not as simple an equation as less contrast equals less cost, Abujudeh notes. More important is implementing procedures aimed at screening patients, identifying those at risk, managing those at risk differently and short- and long-term follow up of patients. "Those procedures come at a cost, and are hard to put a number on, however, preventing adverse outcomes, reducing CIN incidence and other contrast-related adverse events have societal savings," Adujudeh sums.