Absence of platelet TSSC6 results in secondary instability in platelet thrombi formed in vivo. (A) Thrombus formation in vivo was monitored on mesenteric arterioles after topical application in 7.5% FeCl3. Time to artery congestion and primary clot formation in seconds after injury. Each symbol represents 1 monitored arteriole for each wild-type versus TSSC6–/– mouse. Wild-type: 773.4 ± 40.2 seconds; TSSC6–/–: 885.7 ± 36.3 seconds. P < .05; n = 30. (B) Time of clot stability in seconds after injury and occlusion of vessel. Each symbol represents 1 monitored arteriole for each wild-type versus TSSC6–/– mouse. Wild type: 314.4 ± 47.9 seconds; TSSC6–/–: 186.7 ± 38.4 seconds. P < .05; n = 11. (C) Number of thrombi embolizing more than 20 μm in diameter formed during the 30- to 45-minute observation period. Each symbol represents 1 monitored arteriole for each wild-type versus TSSC6–/– mouse. Wild-type: 4.0 ± 1.3 emboli; TSSC6–/–: 9.0 ± 1.9 emboli. P < .05; n = 23.