As Sir William Osler put it, “There is no disease more conductive to clinical humility than aneurysm of the aorta.”

To date, there's no effective treatment for abdominal aortic aneurysm, but researchers at Yale University have developed a new imaging tracer that has the potential to risk-stratify patients with AAA.

“Rupture is the main complication of abdominal aortic aneurysms and it can be fatal. Larger aneurysms are at higher risk for rupture and usually undergo surgical or endovascular repair,” Dr. Mehran M. Sadeghi of the Yale Cardiovascular Research Center, told HCB News.
Smaller aneurysms are managed by monitoring their growth, but many of them that don’t meet criteria for repair do rupture, which can be fatal. The new tracer can be used with SPECT imaging to help monitor matrix metalloproteinase (MMP) activation, which is a process that underlies aneurysm rupture.

To form the basis of the new tracer, the Yale research team created a water-soluble MMP inhibitor. The RYM1-labeled Tc-99m tracer was then compared with another MMP tracer in mouse models of aneurysm.

These studies reveal that the tracer is capable of imaging vessel wall biology with high sensitivity and specificity. Aortic tracer uptake in vivo is associated with vessel wall inflammation.

The team concluded that SPECT/CT imaging with the RYM1-labeled Tc-99m tracer is a promising tool for stratifying risk and could provide new ways to manage AAA.

“If validated in humans, this technique would help identify patients with small aneurysms that are at high risk for rupture, to refer them for aneurysm repair,” said Sadeghi. “In addition, some patients with large aneurysms may not be at high risk for rupture.”

He added that the same approach could be applied to patients with large abdominal aortic aneurysms who are at high risk for surgery, in order to gauge their risk of rupture and potentially avoid unnecessary surgery.

Since the preclinical studied yielded promising results, Sadeghi and his team now have an Investigational New Drug Application underway to use RYM1-labeled Tc-99m in early-stage human studies.

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