M.D. Iisa Lindström studies in her doctoral dissertation the reliability and suitability of muscle parameters measured from pre- and postoperative computed tomography images, in addition to examining the independent predictive impact of muscle size and density on mortality after open vascular surgical and endovascular interventions.
Historically, the estimation of physiological reserves with different scoring methods has been utilized in the optimization of patient selection, especially in the case of surgery for elderly patients, but sarcopenia has not been included in these predictive models. The identification of sarcopenia is complicated by a lack of feasible, cost-effective, accurate, and reproducible diagnostic tools to be used in clinical work. Currently, it is evaluated using questionnaires and functional tests.
Early recognition of sarcopenia may also enable preoperative interventions, such as physical exercise, to improve the condition of the patient and thereby also the results of surgery. Open and endovascular procedures to treat AAA and acute stroke patients are high-risk interventions, and these patients could benefit from the assessment of muscle parameters as markers of sarcopenia.
The included patients were treated at the Centre for Vascular Surgery and Interventional Radiology at Tampere University Hospital between 2001 and 2018. The data was collected retrospectively from the Tampere University Hospital vascular register and patient record database, and from the Fimlab Laboratoriot Oy Ltd database. A total of 301 patients undergoing surgery for an abdominal aortic aneurysm and 242 for an internal carotid stenosis, as well as 312 patients who had suffered a sudden cerebral infarction caused by a blockage of the anterior circulation and were treated with mechanical blood clot removal, i.e. mechanical thrombectomy, were included.
The present thesis aimed to identify muscle parameters that independently predict mortality after the vascular or endovascular intervention from pre-procedural and control computed tomography studies. In four studies, the association of muscle area, density and lean area with short- and long-term survival was studied. The end point was long-term mortality in the abdominal aortic aneurysm and endarterectomy studies, and 3-month postinterventional mortality in the anterior ischaemic stroke study. In addition, changes in the psoas muscle area and density during follow-up were studied in endovascularly treated abdominal aortic aneurysm patients.
Psoas and masseter muscle measurements from computed tomography studies proved to be reliable and repeatable between clinicians. In study I, the density of the psoas muscles, as well as their lean area, at the L2–L3-level axial slices were found to be independent predictors of mortality in patients treated for an abdominal aortic aneurysm. In study II, the relative psoas muscle area change during follow-up was found to be a stronger independent risk factor for mortality than the follow-up psoas muscle area in patients treated by means of endovascular aneurysm repair.
In study III, the masseter muscle area was a significant long-term prognostic factor for carotid stenosis patients subjected to endarterectomy. Furthermore, in study IV, in patients with an acute proximal anterior occlusion, the size and density of the masseter muscle were independently associated with the three-month survival after anterior mechanical thrombectomy.
The results of the present thesis, therefore, suggest that muscle parameters may reflect sarcopenia and that they can be used in the prediction of survival in vascular patients. Muscle parameters are reliable, feasible and readily available for clinical work.
The doctoral dissertation of M.D. Iisa Lindström in the field of vascular surgery titled Sarcopenia As a Predictor of Survival in Vascular Patients will be publicly examined at the Faculty of Medicine and Health Technology of Tampere University at 12 o'clock on Friday 20 August, 2021. The venue is Arvo building Jarmo Visakorpi Auditorium, address: Arvo Ylpön katu 34. Docent Pirkka Vikatmaa from University of Helsinki will be the opponent while Professor Niku Oksala will act as the custos.
Because of COVID-19, Tampere University’s doctoral dissertation defences are not organised as regular events. Iisa Lindström’s dissertation defence is open to 50 participants in the Jarmo Visakorpi hall of the Arvo building. Those attending are asked to register for the event by 18 August with an email sent to iisa.lindstrom [at] tuni.fi.
The event can be followed via remote connection.
The dissertation is available online at
http://urn.fi/URN:ISBN:978-952-03-2018-8