{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T00:44:21Z","timestamp":1787013861361,"version":"build-2736575974"},"reference-count":13,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2018,1,17]],"date-time":"2018-01-17T00:00:00Z","timestamp":1516147200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/501100003006","name":"Eidgen\u00f6ssische Technische Hochschule Z\u00fcrich","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100003006","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Artificial Organs"],"published-print":{"date-parts":[[2018,5]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The HeartWare HVAD is a radial rotary blood pump with a combination of passive magnetic and hydrodynamic bearings to levitate the impeller. The axial gap size between impeller and housing in this bearing and its sensitivity to speed, flow, and pressure difference is difficult to assess. Shear stresses are exceptionally high in this tiny gap making it important for blood damage and related adverse events. Therefore, the aim of this study was to measure the axial gap clearance in the HVAD at different operating conditions employing radiography. To quantify the gap size in the HVAD, the pump was positioned 30 mm in front of the X\u2010ray source employing a microfocus X\u2010ray tube with an acceleration voltage up to 300 kV. Beams were detected on a flat panel detector (Perkin Elmer XRD 1611\u2010CP3). The pump was connected to a tubing circuit with a throttle to adjust flow (0, 5, 10 L\/min) and a water glycerol mixture to set the desired viscosity (1, 4, 8 mPas). Rotational speed was varied between 1800 and 3600 rpm. In this study, for clinically relevant conditions at 5 L\/min and 2700 rpm, the axial gap was 22 \u00b5m. The gap size increased with rotational speeds dependent on the viscosity (2.8, 6.9, and 9.4 \u00b5m\/1000 rpm for 1, 4, and 8 mPas, respectively), but was independent from the volume flow and the pressure head at constant speeds. In summary, using X\u2010ray radiographic imaging small gaps in a rotary blood pump during operation can be measured in a nondestructive contact\u2010free way. The axial hydrodynamic bearing gap in the HVAD pump was determined to be in the range of about three times the diameter of a red blood cell. Its dependence on operating volume flow and generated pressure head across the pump is not pronounced.<\/jats:p>","DOI":"10.1111\/aor.13074","type":"journal-article","created":{"date-parts":[[2018,1,17]],"date-time":"2018-01-17T01:42:55Z","timestamp":1516153375000},"page":"510-515","source":"Crossref","is-referenced-by-count":24,"title":["Investigation of the Axial Gap Clearance in a Hydrodynamic\u2010Passive Magnetically Levitated Rotary Blood Pump Using X\u2010Ray Radiography"],"prefix":"10.1111","volume":"42","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1300-7637","authenticated-orcid":false,"given":"Bente","family":"Thamsen","sequence":"first","affiliation":[{"name":"pd|z Product Development Group Zurich, Department of Mechanical and Process Engineering ETH Zurich Zurich Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mathieu","family":"Plamondon","sequence":"additional","affiliation":[{"name":"Empa, Swiss Federal Laboratories for Material Science and Technology, Center for X\u2010ray Analytics D\u00fcbendorf Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1425-1236","authenticated-orcid":false,"given":"Marcus","family":"Granegger","sequence":"additional","affiliation":[{"name":"Pediatric Heart Center University Children's Hospital, University of Zurich Zurich Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marianne","family":"Schmid Daners","sequence":"additional","affiliation":[{"name":"pd|z Product Development Group Zurich, Department of Mechanical and Process Engineering ETH Zurich Zurich Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rolf","family":"Kaufmann","sequence":"additional","affiliation":[{"name":"Empa, Swiss Federal Laboratories for Material Science and Technology, Center for X\u2010ray Analytics D\u00fcbendorf Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonia","family":"Neels","sequence":"additional","affiliation":[{"name":"Empa, Swiss Federal Laboratories for Material Science and Technology, Center for X\u2010ray Analytics D\u00fcbendorf Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mirko","family":"Meboldt","sequence":"additional","affiliation":[{"name":"pd|z Product Development Group Zurich, Department of Mechanical and Process Engineering ETH Zurich Zurich Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2018,1,17]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1093\/eurheartj\/ehs104"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa1602954"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.healun.2012.10.001"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1097\/MAT.0b013e3182768cfb"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1097\/MAT.0b013e3181dfbab5"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1109\/TMAG.1981.1061166"},{"key":"e_1_2_8_8_1","volume-title":"Str\u00f6mungslehre f\u00fcr den Maschinenbau\u2014Technik und Beispiele","author":"Siekmann HE","year":"2009"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.cirp.2014.05.011"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.csndt.2016.07.001"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/aor.12542"},{"key":"e_1_2_8_12_1","volume-title":"Guyton and Hall Textbook of Medical Physiology","author":"Hall JE.","year":"2016"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1243\/09544119JEIM352"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1046\/j.1525-1594.2003.07188.x"}],"container-title":["Artificial Organs"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1111%2Faor.13074","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/aor.13074","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,23]],"date-time":"2023-09-23T09:19:17Z","timestamp":1695460757000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/aor.13074"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,1,17]]},"references-count":13,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2018,5]]}},"alternative-id":["10.1111\/aor.13074"],"URL":"https:\/\/doi.org\/10.1111\/aor.13074","archive":["Portico"],"relation":{},"ISSN":["0160-564X","1525-1594"],"issn-type":[{"value":"0160-564X","type":"print"},{"value":"1525-1594","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,1,17]]}}}