Circulatory support with larger volume intra-aortic balloon pump vs. standard volume or no-balloon pump during high-risk percutaneous coronary interventions. A randomised study - Zeliaś, Aleksander; Zajdel, Wojciech; Malinowski, Krzysztof; Geremek, Jolanta; Żmudka, Krzysztof (Advances in Interventional Cardiology/Postępy w Kardiologii Interwencyjnej, 2020)