The main issue that needs to be ensured is that the aortic valve replacement
and pressures are working appropiately; if the valve is not working right then you can see a drop in blood pressure and "narrowing" of the difference between systolic and diastolic BP. A good echocardiogram can sort this out; sometimes though, a transesophageal echocardiogram
is needed to look well at the aortic valve.
Dr Brenes-Salazar MD
Mayo Clinic MN