BACKGROUND/ OBJECTIVE: Thromboembolism secondary to atrial fibrillation accounts for approximately one-fourth of all strokes. Although considerable resources have been targeted to pharmacologic prophylaxis, neither the cellular nor the biochemical composition of atrial thrombi is known. Quantitative immunohistochemistry was undertaken to define the composition of atrial thrombi and to explore morphological differences between atrial appendage thrombi and those that embolize. PATIENTS/ METHODS: Serial sections of thrombi obtained during valve replacement surgery or embolectomy from 22 patients with atrial fibrillation were stained with antibodies against fibrin, integrin beta3, or tissue factor and analyzed with NIH-image. RESULTS: Thrombi showed distinct regions staining for either fibrin or platelets and on average, the fibrin-rich regions predominated (P < 0.0001). The platelet content of embolized thrombi was nearly twice that of atrial thrombi (P = 0.02). Non-staining amorphous material comprised nearly half of atrial thrombi in situ, but was rare in embolized thrombi (P < 0.001). Tissue factor colocalized to areas rich in platelets and granulocytes. CONCLUSIONS: The abundance of fibrin relative to platelets underscores the enhanced efficacy of warfarin prophylaxis in clinical trials. The finding of tissue factor localized to platelet-leukocyte clusters suggests its blood-borne origin. Compositional differences between in situ and embolized thrombi suggest directions for investigating propensity for embolization.
BACKGROUND/ OBJECTIVE:Thromboembolism secondary to atrial fibrillation accounts for approximately one-fourth of all strokes. Although considerable resources have been targeted to pharmacologic prophylaxis, neither the cellular nor the biochemical composition of atrial thrombi is known. Quantitative immunohistochemistry was undertaken to define the composition of atrial thrombi and to explore morphological differences between atrial appendage thrombi and those that embolize. PATIENTS/ METHODS: Serial sections of thrombi obtained during valve replacement surgery or embolectomy from 22 patients with atrial fibrillation were stained with antibodies against fibrin, integrin beta3, or tissue factor and analyzed with NIH-image. RESULTS:Thrombi showed distinct regions staining for either fibrin or platelets and on average, the fibrin-rich regions predominated (P < 0.0001). The platelet content of embolized thrombi was nearly twice that of atrial thrombi (P = 0.02). Non-staining amorphous material comprised nearly half of atrial thrombi in situ, but was rare in embolized thrombi (P < 0.001). Tissue factor colocalized to areas rich in platelets and granulocytes. CONCLUSIONS: The abundance of fibrin relative to platelets underscores the enhanced efficacy of warfarin prophylaxis in clinical trials. The finding of tissue factor localized to platelet-leukocyte clusters suggests its blood-borne origin. Compositional differences between in situ and embolized thrombi suggest directions for investigating propensity for embolization.
Authors: Andreas Goette; Jonathan M Kalman; Luis Aguinaga; Joseph Akar; Jose Angel Cabrera; Shih Ann Chen; Sumeet S Chugh; Domenico Corradi; Andre D'Avila; Dobromir Dobrev; Guilherme Fenelon; Mario Gonzalez; Stephane N Hatem; Robert Helm; Gerhard Hindricks; Siew Yen Ho; Brian Hoit; Jose Jalife; Young-Hoon Kim; Gregory Y H Lip; Chang-Sheng Ma; Gregory M Marcus; Katherine Murray; Akihiko Nogami; Prashanthan Sanders; William Uribe; David R Van Wagoner; Stanley Nattel Journal: Heart Rhythm Date: 2016-06-10 Impact factor: 6.343
Authors: Benjamin A T Rodriguez; Arunoday Bhan; Andrew Beswick; Peter C Elwood; Teemu J Niiranen; Veikko Salomaa; David-Alexandre Trégouët; Pierre-Emmanuel Morange; Mete Civelek; Yoav Ben-Shlomo; Thorsten Schlaeger; Ming-Huei Chen; Andrew D Johnson Journal: Am J Hum Genet Date: 2020-07-09 Impact factor: 11.025
Authors: J M Niesten; I C van der Schaaf; G J Biessels; A E van Otterloo; T van Seeters; A D Horsch; M J A Luitse; Y van der Graaf; L J Kappelle; W P T M Mali; B K Velthuis Journal: Neuroradiology Date: 2013-06-21 Impact factor: 2.804
Authors: Matteo Nicola Dario Di Minno; Antonella Tufano; Walter Ageno; Paolo Prandoni; Giovanni Di Minno Journal: Intern Emerg Med Date: 2011-04-02 Impact factor: 3.397
Authors: W E Wysokinski; K P Cohoon; R M Melduni; M Mazur; N Ammash; T Munger; E Konik; T McLeod; Izabeal Gosk-Bierska; R D McBane Journal: Thromb Res Date: 2018-10-10 Impact factor: 3.944