Masashi Tanaka1, Koji Kawahito, Hideo Adachi, Takashi Ino. 1. Department of Cardiovascular Surgery, Omiya Medical Center, Jichi Medical School, 1-847 Amanuma, Saitama 330-0834, Japan. masashi@omiya.jichi.ac.jp
Abstract
OBJECTIVES: Platelet dysfunction contributes to bleeding tendency in acute type A aortic dissection. Particle counting by new laser light-scattering methods more accurately quantifies changes in the number of different-sized platelet aggregates than do conventional optical density methods. We studied platelet aggregation kinetics and patterns of aggregation deficiency in acute-phase aortic dissection with laser light scattering. METHODS: Blood from 20 acute type A aortic dissection patients undergoing surgery was sampled during acute (9.1 +/- 6.8 hours from onset) and chronic (postoperative day 20, control) phases of aortic dissection. Platelet count and aggregability were assessed by optical density and laser light-scattering methods after aggregation was induced (addition of 2.0 microg/mL collagen to samples). RESULTS: Optical density showed significant reduction in acute-phase platelet aggregation (acute vs chronic: 65 +/- 27% vs 77 +/- 17%, P <.03). Laser light scattering showed significant reduction in medium (25-50 microm) and large (50-70 microm) but not small aggregate (9-25 microm) generation (acute vs chronic: small, 1.2 +/- 0.6 x 10(7) vs 1.5 +/- 1.0 x 10(7), NS; medium, 0.6 +/- 0.3 x 10(7) vs 1.1 +/- 0.5 x 10(7), P <.001; large, 1.4 +/- 1.2 x 10(7) vs 2.6 +/- 1.7 x 10(7), P <.001). Acute- versus chronic-phase platelet counts were significantly decreased (1.7 +/- 0.1 x 10(5)/microL vs 3.6 +/- 0.3 x 10(5)/microL, P <.001). CONCLUSIONS: Platelet aggregation is suppressed in acute-phase aortic dissection. This suppression does not occur in the initial phase of small aggregate formation; rather, it occurs during the conglomeration of small aggregates into larger aggregates.
OBJECTIVES: Platelet dysfunction contributes to bleeding tendency in acute type A aortic dissection. Particle counting by new laser light-scattering methods more accurately quantifies changes in the number of different-sized platelet aggregates than do conventional optical density methods. We studied platelet aggregation kinetics and patterns of aggregation deficiency in acute-phase aortic dissection with laser light scattering. METHODS: Blood from 20 acute type A aortic dissection patients undergoing surgery was sampled during acute (9.1 +/- 6.8 hours from onset) and chronic (postoperative day 20, control) phases of aortic dissection. Platelet count and aggregability were assessed by optical density and laser light-scattering methods after aggregation was induced (addition of 2.0 microg/mL collagen to samples). RESULTS: Optical density showed significant reduction in acute-phase platelet aggregation (acute vs chronic: 65 +/- 27% vs 77 +/- 17%, P <.03). Laser light scattering showed significant reduction in medium (25-50 microm) and large (50-70 microm) but not small aggregate (9-25 microm) generation (acute vs chronic: small, 1.2 +/- 0.6 x 10(7) vs 1.5 +/- 1.0 x 10(7), NS; medium, 0.6 +/- 0.3 x 10(7) vs 1.1 +/- 0.5 x 10(7), P <.001; large, 1.4 +/- 1.2 x 10(7) vs 2.6 +/- 1.7 x 10(7), P <.001). Acute- versus chronic-phase platelet counts were significantly decreased (1.7 +/- 0.1 x 10(5)/microL vs 3.6 +/- 0.3 x 10(5)/microL, P <.001). CONCLUSIONS:Platelet aggregation is suppressed in acute-phase aortic dissection. This suppression does not occur in the initial phase of small aggregate formation; rather, it occurs during the conglomeration of small aggregates into larger aggregates.
Authors: Bruno Botelho Pinheiro; Walter V Fagundes; Luís F F Muniz; Mats Dreifaldt; Mikael Arbeus; Domingos S R Souza Journal: Braz J Cardiovasc Surg Date: 2016-04