Thanks sam for your quick reply. I have not tried using workitem query. But worked for me as below,

//First get the required workitems and on each workitem do some logic based on "Related artifact" link defined.
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com.ibm.team.workitem.common.query.IQueryResult<IResolvedResult<IWorkItem>> results = queryClient.getResolvedExpressionResults(projectArea, term, IWorkItem.FULL_PROFILE);

while (results.hasNext(monitor)) {
  IResolvedResult<IWorkItem> workitemResult = (IResolvedResult<IWorkItem>) results.next(monitor);
  IWorkItem workItem = workitemResult.getItem();
  ILinkManager linkManager = (ILinkManager)      teamRepository.getClientLibrary(ILinkManager.class);
  workItemReference =  linkManager.referenceFactory().createReferenceToItem(workItem);

linkQueryPage = linkManager.findLinksBySource(WorkItemLinkTypes.RELATED_ARTIFACT, workItemReference, monitor);
linkCollection = linkQueryPage.getAllLinksFromHereOn();

for (ILink l : linkCollection) {
    System.out.println("URL: " + l.getTargetRef().createURI()+ ", Comment: " + l.getTargetRef().getComment());
    if (l.getTargetRef().createURI().toString().contains("some string that you would be searching as part of URI"))
    //Once you determined that WorkItem with specific URI string
   //DO your logic
    -------
   }
}