Experimental, animal and human studies have shown that the use of ionic contrast media compared with nonionic agents during PCI leads to fewer episodes of thrombus formation, according to two reviews in the March supplement of the Journal of Invasive Cardiology.
In the first review, Mark Fisch, MD, and Frederick Feit, MD, from New York University School of Medicine in New York City, concluded that substantial in vitro evidence exists that shows significant differential effects “of various contrast media on the propagation, mitigation and dissolution of thrombus...These studies have consistently demonstrated that ionic contrast media create a more favorable antithrombotic rather than prothrombotic environment than do the nonionic agents.”
The authors noted that the ionic dimer agent ioxaglate (Hexabrix; Guerbet) had demonstrated the greatest antithrombotic properties compared to its nonionic dimer counterpart, iodixanol (Visipaque; GE Healthcare).
Researchers also cited several clinical studies that were favorable to ionic contrast media. In a retrospective analysis, Gasperetti et al in 1991 found that patients receiving the ionic monomer diatrizoate (Hypaque, GE Healthcare) were significantly less likely to develop thrombus during percutanueous transluminal coronary angioplasty than the group receiving the nonionic monomer iopamidol (IsoVue; Bracco Diagnostics).
Also in 1991, Esplugas et al published the first double-blind, randomized trial results of the effects of contrast media on thrombus formation. They found a significant difference in favor of the ionic dimer ioxaglate versus the nonionic monomer iohexal (Omnipaque; GE Healthcare).
More recently, Le Feuvre et al in 2006 found that the ionic ioxaglate was significantly associated with fewer thrombus formations than the nonionic iodixanol.
“Whether these differences will be meaningful in the current interventional era, with the early administration of clopidogrel, increased usage of prasugrel and better and safer antithrombin agents, will be determined by future clinical trials,” the authors concluded.
In the second review, Steven V. Manoukian, MD, director of cardiovascular research at the Sarah Cannon Research Institute and an interventional cardiologist at Centennial Heart Center, Nashville, Tenn., also concluded that the growing body of experimental and clinical evidence supports ionic low-osmolar contrast media such as ioxaglate as having a more pronounced beneficial antithrombotic effect than nonionic contrast media.
Since virtually all available contrast agents are effective opacifiers, “many clinicians do not explore the other unique characteristics of contrast media, leading to a lack of active decision-making regarding contrast media for an individual patient, contrary to most clinical decisions,” Manoukian wrote.
He said that other properties of contrast media to consider are their osmolality, viscosity, structure, ionicity and thrombogenicity.
Regarding the beneficial thrombogenic properties of ionic contrast material, Manoukian said that if these can be achieved “without the cost, complexity and bleeding complications related to more potent PCI anticoagulation regimens, the overall efficacy and safety balance of PCI will be further shifted toward optimal outcomes.”
He concurred with Fisch and Feit, concluding that further studies need to be conducted testing these agents alongside contemporary PCI techniques and antithrombotic pharmacotherapy.