I assume that you want the angle base and angle direction to be North and Clockwise, which may or may not be the same as AutoCAD is set up in its current session, WHEN your code runs. AFTER your code runs, you want AutoCAD keeps its original angle base and direction. Not surprising at all, you use system variable "ANGBASE" and "ANGDIR" to do it.
You would have code like
Dim aBase As Double
Dim aDir As Integer
''Save variables' current value
aBase=ThisDrawing.GetSysVariable("ANGBASE")
aDir=ThisDrawing.GetSysVariable("ANGDIR")
'' Set variables as needed
ThisDrawing.SetSysVariable("ANGBASE", 3.1415926/2)
ThisDrawing.SetSysVariable("ANGDIR", 1)
On Error Resume Next
DoWork
If err.Number<>0 Then
'' handle possible error
End If
'' Restore the variables back to their original value
ThisDrawing.SetSysVariable("ANGBASE", aBase)
ThisDrawing.SetSysVariable("ANGDIR", aDir)
Private Sub DoWork()
'' Do whatever
End Sub