algo como isso deve funcionar
Sub Initialize
Dim s As New NotesSession
Dim db As NotesDatabase
Dim view As NotesView
Dim doc As NotesDocument
Dim nextdoc As NotesDocument
Dim lastmodifieddate As New NotesDateTime("")
Dim modifieddate As Variant
Dim days As Integer
Dim checkdate as Variant
Set db = s.CurrentDatabase
Set view = db.GetView("$Sent")
Set doc = view.GetFirstDocument
checkdate = DateNumber(2018, 02, 25)
While Not ( doc Is Nothing )
Set nextdoc = view.getnextdocument(doc)
modifieddate=Evaluate("@Modified", doc)
If modifieddate < checkdate Then
Call doc.Remove(True)
'In Notes 6.0 and later you can use the below instead of the above
'if you want to hard delete the document
'Call doc.RemovePermanently(True)
End If
Set doc = nextdoc
Wend
End Sub