REN and cystic kidney disease: Through mass effect, cyst compression of renal vasculature or parenchyma can reduce renal perfusion, leading to a resultant activation of the renin-angiotensin-aldosterone system (RAAS) [5]. In a cross-sectional study by Lee et al., subjects with simple renal cysts had a higher risk of prehypertension and hypertension independent of cardiovascular and metabolic risk factors.