Indications and timing of revascularization for atherosclerotic renal artery stenosis are topics of considerable controversy. Labile hypertension, progressive renal failure, and flash pulmonary edema may be strong indications for revascularization, yet revascularization may carry significant morbidity and mortality risks. Medical therapy alone, however, may also risk deterioration of renal function with worsening morbidity and mortality. We report a case of renal artery stenosis illustrating some of the complexities of decision-making, the limitations of angiography, and the importance of physiologic testing.