Aris Lacis, cardiac surgeon, professor, MD, PhD graduated Riga Medical Institute in 1961. General and thoracic surgeon in P. Stradina University Hospital in Riga (1964–1969). Thoracic and cardiac surgeon in the Latvian Centre for Cardiovascular Surgery (1969–1994). Since 1994 until 2012 – the head of Pediatric Cardiology and Cardiac Surgery Clinic in University Children’s Hospital, Riga; since 2012 – a consulting professor of this Clinic. President of Latvian Association for Pediatric Cardiologists. Author of 395 scientific publications, 3 monographs and 13 patents. Investigator in more than 10 clinical trials including cardiosurgical procedures performed under deep hypothermia, hybrid procedures etc. In may 2009 at first in the world have been used transcutan intramyocardial delivery autologous bone morrow derived progenitor stem cells for 3 months aged patient suffering from idiopathic dilated cardiomyopathy.In November 2010 the first patient with end stage pulmonary hypertension received intrapulmonary implantation autologous stem cells.