Doctoral defence: Jüri Lieberg “Results of surgical treatment and role of biomarkers in pathogenesis and risk prediction in patients with abdominal aortic aneurysm and peripheral artery disease”

On 12 December at 15:00 Jüri Lieberg will defend his doctoral thesis “Results of surgical treatment and role of biomarkers in pathogenesis and risk prediction in patients with abdominal aortic aneurysm and peripheral artery disease” for obtaining the degree of Doctor of Philosophy (in Medicine).

Supervisor:
Professor Jaak Kals, University of Tartu

Opponent:
Professor Kevin Mani, Uppsala University (Sweden)

Summary
Abdominal aortic aneurysm (AAA) is a complex pathology with a high mortality rate (around 80%) due to its complication, AAA rupture, which is why timely treatment is crucial. AAA prevalence and incidence rates have decreased over the last 20 years, the current prevalence in 65-year-old men is between 1.3% and 3.3%. Peripheral artery disease (PAD) or lower extremity arterial disease is a manifestation of systemic atherosclerosis with a prevalence of 2.7-3% in population aged 45-49 years, increasing up to 18.2 % in persons aged 60-90 years. However, PAD patients remain underdiagnosed and -treated with regard to guideline-directed medical therapy. In the present thesis, patients with elective and emergency AAA and with symptomatic PAD were studied. We aimed to evaluate the results of surgical and endovascular therapy of patients with elective AAA (eAAA) and ruptured (rAAA) and symptomatic PAD; and to determine the role of functional and biochemical markers in pathogenesis and risk prediction in these patients.

In patients with eAAA, 30-day, 90-day, and 5-year all-cause mortality rates were 0.9%, 2.6%, and 32%, respectively. In patients with rAAA, 30-day, 90-day, and 5-year all-cause mortality rates were 22.9%, 33.3%, and 55.1%, respectively. 30-day mortality, and complication and reintervention rates for endovascular aneurysm repair (EVAR) and open surgical repair in eAAA patients were similar. The EVAR procedure is an independent risk factor for 5-year mortality.
The levels of only four amino acids and four phosphatidylcholines were found to be significantly lower after adjustment for confounders among the AAA patients compared with the controls. There were no differences in the metabolites distinguishing the AAA patients with slow or fast growth from the controls, or distinguishing the patients with slow growth from those with fast growth.

The rate of operative mortality in PAD patients was 3.7%, the cumulative patency rate for all bypass operations was 82.9%, 38.7% and 21.3% at 30 days, 3 and 5 years, respectively. Small artery elasticity above the median was independently associated with decreased all-cause and cardiovascular disease mortality in PAD patients.