Adrian Karlsson: Endovascular treatment of ischemic stroke
Adrian Karlsson’s doctoral thesis explores how different factors throughout the chain of care influence outcomes for stroke patients treated with thrombectomy.
ADRIAN KARLSSON
Dissertation defense: 5 June 2026 (click for details)
Doctoral thesis: Endovascular treatment of stroke - Key determinants of technical and clinical outcome
Research area: Radiology and Imaging
Sahlgrenska Academy, The Institute of Clinical Sciences
Ischemic stroke occurs when a blood clot - most often an embolus - blocks one of the brain’s blood vessels, causing an acute lack of oxygen. The affected area immediately loses function, and after some time nerve cells begin to die due to oxygen deprivation. Rapid restoration of blood flow reduces the risk of permanent injury.
Today, two main treatment strategies are used: intravenous thrombolysis, where a clot-dissolving drug is administered through a peripheral vein and transported systemically to the blocked vessel in the brain, and endovascular treatment. In endovascular treatment, a catheter is inserted into a large blood vessel, usually through the groin, and navigated to the blocked artery under continuous X-ray guidance. The clot is then mechanically removed using specially designed instruments.
“There is currently a global effort underway to determine which patients truly benefit from treatment and how outcomes can be optimized for those patients, says Adrian Karlsson, resident physician in neurointervention and neuroradiology at Sahlgrenska University Hospital and doctoral student at the Institute of Clinical Sciences”.
Treatment techniques and clot composition
The thesis includes four studies investigating different factors that influence outcomes in endovascular treatment - also known as mechanical thrombectomy - for ischemic stroke.
“My research focuses on understanding how different factors throughout the chain of care affect outcomes for patients undergoing thrombectomy. We have studied factors during the patient’s journey to endovascular treatment, treatment techniques, how procedural outcomes are evaluated, and whether the histological composition of the clot influences the result”.
Two fundamentally different techniques are currently used in endovascular stroke treatment: aspiration and stent retriever thrombectomy. In stent retriever procedures, a self-expanding metal stent is placed across the clot and then withdrawn together with the clot. In aspiration treatment, a catheter is instead advanced to the clot, negative pressure is applied, and the clot is suctioned against the catheter tip before being removed.
“We demonstrated that aspiration, in a Swedish healthcare setting, leads to shorter procedure times and improved patient outcomes. The method is also less expensive”.
The researchers also analyzed how the size and composition of emboli affected treatment outcomes. The study showed that larger clots were associated with more technically complex procedures, longer procedure times, and poorer clinical outcomes. In addition, clots rich in red blood cells were linked to better functional recovery for patients.
What has been the most rewarding and challenging part of the PhD project?
“The most rewarding and challenging aspect has been trying to understand the extensive and complex network that makes up modern stroke care, and how the different parts of the healthcare chain interact to help the patient”.
Text: Susanne Lj Westergren
History – Thrombectomy, or endovascular stroke treatment, was first performed by Dr. Gunnar Wikholm at Sahlgrenska University Hospital. Large, randomized studies demonstrating major treatment benefits in large vessel occlusion were presented in 2015–2016. Since then, the field has expanded significantly, both in terms of the number of patients treated and the indications for treatment.