Using TFS API, how can I find the comments which were made on a Code Review?

We have a new requirement to pull code review comments from TFS and here is a short example of what we implemented. The workItemId has to be queried through another method. You can even look it up in Visual Studio or through a TFS query in the UI. This is a small subset of what is available and what we are using. I found this link to be helpful after digging through MSDN.

 public List<CodeReviewComment> GetCodeReviewComments(int workItemId)
 {
        List<CodeReviewComment> comments = new List<CodeReviewComment>();

        Uri uri = new Uri(URL_TO_TFS_COLLECTION);
        TeamFoundationDiscussionService service = new TeamFoundationDiscussionService();
        service.Initialize(new Microsoft.TeamFoundation.Client.TfsTeamProjectCollection(uri));
        IDiscussionManager discussionManager = service.CreateDiscussionManager();

        IAsyncResult result = discussionManager.BeginQueryByCodeReviewRequest(workItemId, QueryStoreOptions.ServerAndLocal, new AsyncCallback(CallCompletedCallback), null);
        var output = discussionManager.EndQueryByCodeReviewRequest(result);

        foreach (DiscussionThread thread in output)
        {
            if (thread.RootComment != null)
            {
                CodeReviewComment comment = new CodeReviewComment();
                comment.Author = thread.RootComment.Author.DisplayName;
                comment.Comment = thread.RootComment.Content;
                comment.PublishDate = thread.RootComment.PublishedDate.ToShortDateString();
                comment.ItemName = thread.ItemPath;
                comments.Add(comment);
            }
        }

        return comments;
    }

    static void CallCompletedCallback(IAsyncResult result)
    {
        // Handle error conditions here
    }

    public class CodeReviewComment
    {
        public string Author { get; set; }
        public string Comment { get; set; }
        public string PublishDate { get; set; }
        public string ItemName { get; set; }
    }