Gadolinium can be used as substitute for iodine contrast in some interventional imaging procedures
Gadolinium might be an alternative, stop-gap solution for the current iodine imaging contrast shortage in interventional procedures. Hospitals are looking for alternatives to scarce iodine contrast agents and experts say magnetic resonance imaging (MRI) gadolinium contrast agents can be used as a substitute in some cases. Experts say MRI contrast may be able to help specifically in interventional and peripheral vascular applications
Gadolinium has about one-third the opacity of iodine contrast agents under X-ray imaging modalities, including computed tomography (CT), radiographic fluoroscopy (R/F) and both fixed and mobile angiography systems used in operating rooms (ORs) and cath labs. Since it has a lower opacity, it has limited applications. At centers were contrast is not available, they are sending patients for alternative imaging exams, including MRI, PET-CT or contrast ultrasound. But if these solutions will not suffice, gadolinium can be used in some situations.
"What we are trying do to in situations that can use less dense contrast, we employed gadolinium," explained Alan H. Matsumoto, MD, FSIR, FACR, FAHA, professor of radiology, chair of the Department of Radiology at the University of Virginia, vice chair of the American College of Radiology (ACR) Board of Chancellors, and the chairman of the ACR Commission on Interventional and Cardiovascular Radiology. "Most of these are in the gastro-intestinal (GI) tract to look at the bile duct, pancreatic ducts or the ureter and bladder. We also will try to use it in rare instances intravascularly for studying vessels, such as those in the leg or kidney."
Matsumoto said when using gadolinium in X-ray modalities, the optimal kVp is around 95-96. At the University of Virginia, he said gadolinium is being used during the shortage for endoscopic retrograde cholangiopancreatography (ERCP), retrograde urography and in some peripheral procedures.
Gadolinium contrast can be used for cath lab angiography
Matsumoto said use of gadolinium as an intravascular contrast agent for X-ray angiography is nothing new, with a lot of research being done on this topic in the late 1990s and early 2000s. There was a movement in interventional cardiology and interventional radiology at that time looking at gadolinium for use in renal insufficiency patients to prevent kidney damage. He said the substitution was made in patients with an estimated glomerular filtration rate (eGFR) of less than 30. He cited a study his own center had published on this topic in the journal Radiology.[1]
"We have had preliminary conversations at our hospital about the use of gadolinium, and there are formulations of gadolinium that are safe for inter vascular use," explained Kirk Garratt, MD, MSc, MSCAI, medical director of the Center for Heart and Vascular Health, the John H. Ammon Chair of Cardiology at ChristianaCare, and a past president of the Society of Cardiovascular Angiography and Interventions (SCAI). "The K-edge of gadolinium is a little different, so the images are not quite as good, and of course the cost is significantly higher."
If gadolinium were to be used as a substitute in the cath lab, he said there is a need for verification of the safety profile before using it in patients. "I have not thought about use of gadolinium in the cath lab in a long time, so I want to be sure we know everything about its use first before moving forward, especially in the elective procedure population," Garratt said.
"We thought at one time that gadolinium would be an excellent product to use in patients with renal insufficiency, but subsequently we learned that there is a subset of patients in that population that is at elevated risk of a systemic sclerotic response that can be unexpected and quite serious," Garratt explained.
Matsumoto said interventional cardiology colleagues at the University of Virginia who had used gadolinium for coronary artery procedures in the cath lab said the lower opacity makes it more difficult to see the vessels.
Garratt said there has been a lot of waste of iodine contrast agent in cath labs because of the way it comes packaged and the unused amounts from cases has just been disposed. He said some cardiology departments are now trying to conserve any remaining contrast from cases to reuse in other cases. Some hospitals are also working with their pharmacy departments to breakdown the larger packages of contrast they do have into smaller dose syringes. Ideally, Garratt said this needs to be done in a clean room in the pharmacy department.
How serious is the contrast shortage impacting patient care?
The contrast shortage is supposed to be resolved by the end of June or beginning of July, but there are concerns this duration will lead to deferring procedures and imaging exams unless the patient is facing severe injury, death or loss of limbs. Matsumoto said his hospital already has instituted a triage system where only critical patients will be given contrast imaging exams or interventional procedures.
In vascular surgery, he said they have delayed non-essential endovascular stent graft procedures because of the contrast shortage. For patients who do not want to wait, they are being offered open surgical repair procedures, setting the clock back on advances in minimally invasive endovascular aortic repair (EVAR) 10-20 years.
Garratt has very serious concerns that hospitals may soon begin postponing non-critical and elective patient procedures just because they lack the contrast agent to be able to navigate catheters and devices inside the blood vessels. He has already heard of three hospital systems that are now doing this.
What caused the iodine contrast shortage?
GE Healthcare, which supplied more than 50% of the iodine contrast on the U.S. market, had its Shanghai, China, manufacturing facility shout down for several weeks due to local COVID-19 policies. China has shut down several cities recently in attempts to contain the spread of an outbreaks there. The vendor said they recently were able to reopen the factory, but it has only been operating at about 50% capacity.
"We are working to return to full capacity as soon as local authorities allow," a GE spokesman said last week. "Our priority is delivering for our customers and their patients, and we are working around the clock to expand capacity of our iodinated contrast media products."
This effort includes boosting production at GE's Cork, Ireland, manufacturing plant. It is now operating 24/7 to try to fill the contrast shortage gap. GE also is working with Shanghai authorities to enable increasing the numbers of workers back to the plant so production can be increased. Shipments of contrast from China also were converted from container ships to air shipments to expedite arrival. The vendor also optimized production to focus on three main product variations rather than multiple variants, which has helped increase production.
GE hopes to have the supply of contrast normalized again by late June or early July. However, Matsumoto said many physicians he has spoken with have concerns that if COVID numbers spike again in China, there could be further shutdowns of contrast production.
Related Imaging Contrast Agent Shortage News:
VIDEO: Gadolinium being substituted for iodine contrast in some procedures due to shortage — Interview with Alan H. Matsumoto, MD
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VIDEO: How the iodine contrast shortage is impacting interventional cath labs — Interview with Kirk Garratt, MD
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VIDEO: Imaging contrast shortage is delaying procedures and causing rationing — Interview with Alan H. Matsumoto, MD
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Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com