Clinical trial NCT04811222: DOTATATE PETMRI AAA Study
Official title: Gallium-DOTATATE PET-MR Imaging to Detect Macrophages in Abdominal Aortic Aneurysms
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Abdominal Aortic Aneurysm
Lead sponsor: University Health Network, Toronto
Sponsor class: OTHER
First posted: 2021-03-23
Enrollment: 55
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Ga-DOTATATE PETMRI scan
Primary purpose: DIAGNOSTIC

Brief summary: Abdominal Aortic Aneurysm (AAA) screening and an aging population have increased the prevalence of AAA diagnoses. Small AAAs (\<5.5cm) are monitored with ultrasound. Large AAAs may rupture and this is usually fatal. Surgery is considered at a crude size threshold of 5.5cm when the annual rupture risk reaches 5%. AAA size is the only predictor of growth and rupture available but growth is non-linear and some small AAAs rupture. Thus, only 1 in 20 patients treated at 5.5cm will have benefited from rupture prevention in the year following surgery, and others may miss out on life-saving surgery. This study will develop an imaging tool PETMRI with radiotracer Ga- DOTATATE with high clinical utility, to improve prediction of aneurysm growth and risk.

Detailed description: The prevalence of abdominal aortic aneurysm (AAA) in those over 65 years is 4-8% and rising. Currently, AAA size is the only metric to determine risk of growth/rupture; we are unable to image the underlying disease process. Using size alone is problematic. For small AAAs there is no consensus between surgical societies on appropriate surveillance intervals. AAA growth is non-linear and thus some small AAAs may rupture between screening intervals.

Macrophage mediated inflammation leads to weakening of the aortic wall. Our own laboratory work indicates macrophages correlate with AAA severity in mice. In humans, activated macrophages express SomatoSTatin Receptor 2 (SSTR2). For the first time ever, using a radiotracer probe specific for SSTR 2 (gallium-dotatate), we will detect activated macrophages in AAAs using Positron Emission Tomography- Magnetic Resonance Imaging (PET-MRI). Patients attending the University Health Network (UHN) Vascular clinic undergoing ultrasound surveillance of small AAAs of differing sizes will be imaged with Ga-Dotatate PET-MRI. We will correlate aneurysm size and anatomical information with in-vivo imaging of aortic macrophages detected with Ga-Dotatate, to determine the risk of aneurysm growth.

Eligibility criteria: Inclusion Criteria:

1. Diagnosis of asymptomatic abdominal aortic aneurysm AAA \>3cm in maximum diameter;
2. Minimum 2 years prior ultrasound or CT imaging of their AAA;
3. No prior treatment for AAA;
4. Age \>50 years;
5. No contraindications to PET/MRI, such as claustrophobia;

Exclusion Criteria:

1. Pregnant females. All women of child-bearing potential must receive a negative urine pregnancy test prior to administration of 68Ga-DOTATATE;
2. Allergy and/or hypersensitivity to MRI contrast agents (gadolinium) or components of 68Ga-DOTATATE drug product (as listed in IB);
3. Presence of pacemaker or implanted cardioverter defibrillator (ICD);
4. History of alcohol or substance abuse.

Primary outcomes:
measure: 68-Ga DOTATATE uptake
timeFrame: within 6 months after obtaining consent
Secondary outcomes:
Other outcomes:
Locations:
city: Toronto
country: Canada
facility: University Health Network
state: Ontario
Study officials:
affiliation: University Health Network, Toronto
name: Patrick Veit-Haibach
role: PRINCIPAL_INVESTIGATOR
References: