This is how I interpreted it.
The patient has diastolic hypertension. This leads to activation of RAAS System. Activation of RAAS will increase Aldosterone.
Increase in Aldosterone result in increase in sodium reabsorption but the question is telling he is unlikely to get peripheral edema directing towards the " Aldosterone escape" mechanism. The mechanism is due to release of ANP/BNP.
ANP/BNP acts mainly by dilating the precapillary arterioles resulting in natriuresis and "Aldosterone escape" mechanism.
Good picture showing the anatomy of the thigh from a T2 MRI perspective.