My initial approach to a double valve was through a 3rd-4th interspace incision above the nipple. This is a very acceptable approach, although it does make visualization of the mitral valve challenging at times. To overcome this, I have decided to approach the  double valves via a mitral valve incision without rib transection.  It is also important to place the arm over the head on an orthopedic sling.  The incision should be aligned with the middle of the sternum. This allows better visualization of the mitral valve.  The aortic valve may appear a bit further away but is very accessible.  Care must be taken in performing the aortotomy and directing the incision into the non coronary sinus.  Another benefit is that the risk of damaging the right mammary with the atrial lift post is much less.

I have enclosed a picture of an AVR + MVR on a patient with large breast implants (another benefit of this approach).  I have even performed double valves along with replacing the ascending aorta.

double valve approach with arm on sling