Table 2. Drugs against AAA tested in clinical trials.

Drugs	Evidence from preclinical studies	Evidence from clinical studies	New clinical trials
Statins	Might limit AAA development through its anti-inflammatory and antioxidant properties [12].	Decrease in vascular MMP9 [13]. Inconsistent data regarding AAA progression [16–18]. Statins improve survival after AAA repair [16,19,20].	Prospective and multicentre rigorous trials are needed to clarify the impact of statins on AAA growth.
Antihypertensive drugs	Antihypertensive drugs ameliorate AAA formation [21–28].	Propranolol, telmisartan and ACEi failed to reduce AAA formation and growth [29,30]. Risk of faster AAA growth with ACEi [37].	Prospective trials in patients with small AAA will be required in view of reduced PWS and PWRI.
Doxycycline	Reduction of incidence of AAA, preserving elastin integrity and attenuating gelatinolytic activity [40–43].	Doxycycline suppressed aortic expression of MMP [44–45]. Reduction in serum C-reactive levels [48–50]. Doxycycline does not attenuate aneurysm growth [50].	Clinical trials with longer follow-up.
Anti-platelet and anti-thrombotic therapy	Limitation of aortic rupture. Reduction of aneurysm diameter [52–54].	Inconsistent data regarding aneurysm growth [56–57]. Increased risk of bleeding in the event of AAA rupture [56]. Risk of type II endoleaks in patients subjected to EVAR [61–62].	New and high-quality clinical trials are essential.
Other drugs with anti-inflammatory properties	Cyclosporin A reduces aneurysm expansion [97].	Pemirolast does not significantly affect AAA growth [95]. Lack of efficacy of canakinumab on AAA size [96].	Ongoing clinical trial testing cyclosporine A.
Metformin	Attenuation of vascular inflammation, ROS production, signalling and neovascularization [78–81].	Observational studies support the ability of metformin to ameliorate AAA progression and aneurysm-related events [75–81].	Randomised controlled clinical trials are needed to clarify this conclusion.
Stem cells	Lack of consistency among studies regarding cell types, sources, doses, and routes of administration [82].	The VIVAAA trial was prematurely interrupted. ARREST trial interim results: suppression of inflammation and reduced aortic diameter growth [90].	New clinical trials with a longer follow up.

AAA, abdominal aortic aneurysm; ACEi, angiotensin-converting enzyme inhibitors; EVAR, endovascular aneurysm repair; MMP, matrix metalloproteinase; PWRI, aortic peak wall rupture index; PWS, aortic peak wall stress; ROS, reactive oxygen species.