The state column of systransactions displays information about the current state of each transaction.
At any given time, a local or external transaction may be executing a command, aborted, committed, and so forth. Additionally, distributed transactions can be in a prepared state, or can be heuristically completed or rolled back.
The connection column displays information about the state of the transaction’s connection. You can use this information to determine whether a transaction is currently attached to or detached from a process. Transactions in X/Open XA environments may become detached from their initiating process, in response to requests from the transaction manager.
See sp_transactions in the Reference Manual: Procedures for a complete list and description of possible coordinator values.