{"id":6476,"date":"2026-10-19T09:48:57","date_gmt":"2026-10-19T09:48:57","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-laeknavisindum-alexandra-aldis-heimisdottir\/"},"modified":"2026-10-19T09:48:57","modified_gmt":"2026-10-19T09:48:57","slug":"doktorsvorn-i-laeknavisindum-alexandra-aldis-heimisdottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-laeknavisindum-alexandra-aldis-heimisdottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00e6knav\u00edsindum – Alexandra Ald\u00eds Heimisd\u00f3ttir"},"content":{"rendered":"
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F\u00f6studaginn 12. j\u00fan\u00ed ver Alexandra Ald\u00eds Heimisd\u00f3ttir doktorsritger\u00f0 s\u00edna \u00ed l\u00e6knav\u00edsindum vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: Bl\u00e6\u00f0ingar eftir hjartaa\u00f0ger\u00f0ir: T\u00ed\u00f0ni, \u00e1h\u00e6ttu\u00fe\u00e6ttir, fylgikvillar og horfur. Bleeding following cardiac surgery: Incidence, risk factors, complications and outcomes.<\/p>\n

Andm\u00e6lendur eru dr. Lars Erik S\u00f6ren Berg, pr\u00f3fessor og yfirl\u00e6knir vi\u00f0 H\u00e1sk\u00f3lasj\u00fakrah\u00fasi\u00f0 \u00ed Link\u00f6ping, og dr. John-Peder Escobar Kvitting, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lasj\u00fakrah\u00fasi\u00f0 og H\u00e1sk\u00f3lann \u00ed Osl\u00f3.<\/p>\n

Umsj\u00f3narkennari og lei\u00f0beinandi hefur veri\u00f0 T\u00f3mas Gu\u00f0bjartsson, pr\u00f3fessor en vegna veikindaleyfis er umsj\u00f3narkennari P\u00e1ll Helgi M\u00f6ller, pr\u00f3fessor, sem einnig er n\u00faverandi forst\u00f6\u00f0uma\u00f0ur fr\u00e6\u00f0asvi\u00f0s \u00ed skur\u00f0l\u00e6knisfr\u00e6\u00f0i. \u00cd doktorsnefnd s\u00e1tu Anders Jeppsson, pr\u00f3fessor, Karl K. Andersen, pr\u00f3fessor og Sigurbergur K\u00e1rason, pr\u00f3fessor.<\/p>\n

S\u00e6d\u00eds S\u00e6varsd\u00f3ttir, pr\u00f3fessor og deildarforseti L\u00e6knadeildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 09:00.<\/p>\n

\u00c1grip<\/strong><\/p>\n

Bl\u00e6\u00f0ingar eftir hjartaa\u00f0ger\u00f0ir eru algengur og kl\u00edn\u00edskt mikilv\u00e6gur fylgikvilli sem tengist aukinni sj\u00fakd\u00f3msbyr\u00f0i, d\u00e1nart\u00ed\u00f0ni, lengri sj\u00fakrah\u00fasdv\u00f6l og h\u00e6rri kostna\u00f0i fyrir heilbrig\u00f0iskerfi\u00f0. \u00der\u00e1tt fyrir a\u00f0 \u00fdmsar skammt\u00edmaaflei\u00f0ingar mikilla bl\u00e6\u00f0inga og endura\u00f0ger\u00f0a vegna bl\u00e6\u00f0ingar s\u00e9u vel \u00feekktar, er minna vita\u00f0 um langt\u00edmahorfur \u00feessara sj\u00faklinga og ni\u00f0urst\u00f6\u00f0ur ranns\u00f3kna \u00e1 \u00e1kve\u00f0num \u00e1h\u00e6ttu\u00fe\u00e1ttum hafa veri\u00f0 misv\u00edsandi. Markmi\u00f0 \u00feessarar ritger\u00f0ar var a\u00f0 rannsaka bl\u00e6\u00f0ingafylgikvilla eftir hjartaa\u00f0ger\u00f0ir, me\u00f0 s\u00e9rstakri \u00e1herslu \u00e1 krans\u00e6\u00f0ahj\u00e1veitua\u00f0ger\u00f0ir, \u00e1h\u00e6ttu\u00fe\u00e6tti mikilla bl\u00e6\u00f0inga og afdrif sj\u00faklinga til skamms og langs t\u00edma.<\/p>\n

Ritger\u00f0in er bygg\u00f0 \u00e1 fimm afturskyggnum h\u00f3pranns\u00f3knum sem n\u00e1\u00f0u til heillar \u00fej\u00f3\u00f0ar. Ranns\u00f3kn I bygg\u00f0ist \u00e1 g\u00f6gnum r\u00famlega 48 \u00fe\u00fasund sj\u00faklinga \u00far SWEDEHEART-gagnagrunninum sem gengust undir krans\u00e6\u00f0ahj\u00e1veitu og\/e\u00f0a hjartalokuskiptaa\u00f0ger\u00f0 \u00ed Sv\u00ed\u00fej\u00f3\u00f0 \u00e1 \u00e1runum 2006\u20132015, en ranns\u00f3knir II\u2013V n\u00e1\u00f0u til allra sj\u00faklinga sem gengust undir krans\u00e6\u00f0ahj\u00e1veitua\u00f0ger\u00f0 \u00e1 \u00cdslandi \u00e1 \u00e1runum 2001\u20132022. Ranns\u00f3knir I og II s\u00fdndu a\u00f0 endura\u00f0ger\u00f0 vegna bl\u00e6\u00f0ingar tengdist markt\u00e6kt aukinni 30 og 90 daga d\u00e1nart\u00ed\u00f0ni, h\u00e6rri t\u00ed\u00f0ni heilabl\u00f3\u00f0falls, br\u00e1\u00f0s n\u00fdrnaska\u00f0a og lengri sj\u00fakrah\u00fasdv\u00f6l. Hins vegar tengdist endura\u00f0ger\u00f0 ekki aukinni langt\u00edmad\u00e1nart\u00ed\u00f0ni me\u00f0al \u00feeirra sj\u00faklinga sem lif\u00f0u af fyrsta t\u00edmabili\u00f0 eftir a\u00f0ger\u00f0. Ranns\u00f3kn III s\u00fdndi a\u00f0 h\u00e6kku\u00f0 dreifibreidd rau\u00f0ra bl\u00f3\u00f0korna (RDW) fyrir a\u00f0ger\u00f0 tengdist sj\u00e1lfst\u00e6tt auknum bl\u00e6\u00f0ingum eftir a\u00f0ger\u00f0, meiri \u00fe\u00f6rf fyrir bl\u00f3\u00f0hlutagjafir, t\u00ed\u00f0ari endura\u00f0ger\u00f0um vegna bl\u00e6\u00f0ingar og fleiri fylgikvillum, en ekki aukinni 30 daga d\u00e1nart\u00ed\u00f0ni. Ranns\u00f3kn IV s\u00fdndi a\u00f0 notkun SSRI\/SNRI lyfja fyrir a\u00f0ger\u00f0 tengdist hvorki aukinni bl\u00e6\u00f0ingu, bl\u00f3\u00f0hlutagj\u00f6fum, fylgikvillum n\u00e9 d\u00e1nart\u00ed\u00f0ni eftir krans\u00e6\u00f0ahj\u00e1veitua\u00f0ger\u00f0. A\u00f0 lokum s\u00fdndi ranns\u00f3kn V fram \u00e1 verulega l\u00e6kkun \u00ed t\u00ed\u00f0ni bl\u00f3\u00f0hlutagjafa \u00e1 18 \u00e1ra t\u00edmabili, sem l\u00edklega endurspeglar framfarir \u00ed skur\u00f0t\u00e6kni, bl\u00f3\u00f0sparandi a\u00f0fer\u00f0um og me\u00f0fer\u00f0 bl\u00e6\u00f0inga og bl\u00f3\u00f0hlutagjafa. Kvenkyn, l\u00e1gur l\u00edkams\u00feyngdarstu\u00f0ull, notkun bl\u00f3\u00f0fl\u00f6guhemjandi lyfja og skert n\u00fdrnastarfsemi reyndust mikilv\u00e6gir \u00e1h\u00e6ttu\u00fe\u00e6ttir mikilla bl\u00e6\u00f0inga.<\/p>\n

Ni\u00f0urst\u00f6\u00f0urnar veita n\u00fdja inns\u00fdn \u00ed bl\u00e6\u00f0ingafylgikvilla eftir hjartaa\u00f0ger\u00f0ir og undirstrika mikilv\u00e6gi \u00e1h\u00e6ttumats fyrir a\u00f0ger\u00f0, snemmb\u00e6rrar \u00edhlutunar og n\u00fat\u00edmalegrar bl\u00f3\u00f0stj\u00f3rnunar til a\u00f0 b\u00e6ta horfur sj\u00faklinga.<\/p>\n

Abstract<\/strong><\/p>\n

Bleeding following cardiac surgery is a common and clinically important complication associated with increased morbidity, mortality, prolonged hospital stay, and higher healthcare costs. Although several short-term consequences of excessive bleeding and re-exploration are well recognised, less is known about long-term outcomes, and findings regarding certain proposed risk factors have been conflicting. This thesis investigates bleeding complications after cardiac surgery, with particular emphasis on coronary artery bypass grafting (CABG), risk factors for excessive bleeding, and both short- and long-term patient outcomes.<\/p>\n

The thesis is based on five retrospective nationwide cohort studies. Study I included over 48,000 patients from the SWEDEHEART registry who underwent CABG and\/or valve replacement surgery in Sweden between 2006 and 2015, while Studies II\u2013V included all patients undergoing CABG in Iceland between 2001 and 2022. Papers I and II showed that re-exploration for bleeding was associated with significantly increased 30- and 90-day mortality, higher rates of stroke, acute kidney injury, and prolonged hospital stay. However, re-exploration was not associated with increased long-term mortality among patients surviving the early postoperative period. Paper III showed that elevated preoperative red cell distribution width (RDW) was independently associated with increased postoperative bleeding, transfusion requirements, re-exploration for bleeding, and perioperative complications, but not with increased 30-day mortality. Paper IV demonstrated that preoperative SSRI\/SNRI therapy was not associated with increased bleeding, transfusion requirements, perioperative complications, or mortality after CABG. Finally, Paper V showed a substantial decline in perioperative transfusion rates over an 18-year period, likely reflecting improvements in surgical techniques, blood conservation strategies, and perioperative transfusion management. Female sex, low body mass index, antiplatelet therapy, and impaired renal function were identified as important predictors of excessive bleeding.<\/p>\n

Overall, the findings provide new insights into bleeding complications after cardiac surgery and highlight the importance of preoperative risk stratification, timely intervention, and modern blood management strategies to improve patient outcomes.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Alexandra Ald\u00eds Heimisd\u00f3ttir er f\u00e6dd \u00e1ri\u00f0 1994 \u00ed Reykjav\u00edk. H\u00fan lauk st\u00fadentspr\u00f3fi af n\u00e1tt\u00farufr\u00e6\u00f0ibraut Menntask\u00f3lans vi\u00f0 Hamrahl\u00ed\u00f0 \u00e1ri\u00f0 2014 og l\u00e6knapr\u00f3fi fr\u00e1 l\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2021. A\u00f0 loknu s\u00e9rn\u00e1msgrunns\u00e1ri starfa\u00f0i Alexandra sem s\u00e9rn\u00e1msl\u00e6knir vi\u00f0 meinafr\u00e6\u00f0ideild Landsp\u00edtala. \u00c1ri\u00f0 2025 flutti h\u00fan til Bergen \u00ed Noregi \u00fear sem h\u00fan h\u00f3f framhaldsn\u00e1m \u00ed meinafr\u00e6\u00f0i vi\u00f0 Patologiavdelingen \u00e1 Haukeland-h\u00e1sk\u00f3lasj\u00fakrah\u00fasinu. Samhli\u00f0a n\u00e1mi og kl\u00edn\u00edskum st\u00f6rfum hefur h\u00fan sinnt kl\u00edn\u00edskum ranns\u00f3knum fr\u00e1 \u00f6\u00f0ru \u00e1ri \u00ed l\u00e6knan\u00e1mi.<\/p>\n

Foreldrar Alexandru eru Heimir Karlsson, \u00fatvarps- og sj\u00f3nvarpsma\u00f0ur \u00e1 Bylgjunni, og R\u00fana Hjaltested Gu\u00f0mundsd\u00f3ttir, kennari, s\u00e9rfr\u00e6\u00f0ingur \u00ed s\u00f6gu l\u00e6knisfr\u00e6\u00f0innar og fornleifa- og listfr\u00e6\u00f0ingur. Samb\u00fdlisma\u00f0ur Alexandru er Hilmar \u00d3marsson t\u00f6lvunarfr\u00e6\u00f0ingur. D\u00f3ttir \u00feeirra er Emil\u00eda Eldey.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5897,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2026-06-12T09:00:00+00:00","_phd_date_end":"2026-06-12T12:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"Bl\u00e6\u00f0ingar eftir hjartaa\u00f0ger\u00f0ir: T\u00ed\u00f0ni, \u00e1h\u00e6ttu\u00fe\u00e6ttir, fylgikvillar og horfur. 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