There are a number of ways to get issues from IswIssueObjRefs. This article describes the simplest way to get all issues with a reference to an item, and get an attribute of an issue using the SystemWeaver API.
Example
private static void GetIssueFromIssueReference(IswItem item)
{
//Get all issues that has a reference to the item
IswIssueObjRefs issueObjRefs = item.GetAllIssueRefs();
//Getting the first issue in the list
IswIssue issue = issueObjRefs[0].Issue;
//Getting the attribute with SID = "AT_SID"
IswAttribute attribute = issue.Attribute("AT_SID");
}