Case Presentation: A 64-year-old year old woman with no personal or family history of HTN was diagnosed with right renal angiomyolipoma incidentally on work up for latent TB and referred to interventional radiology for partial right RAE. On routine follow up one week post procedure, she was noted to be normotensive. One-month post procedure while receiving a screening mammogram, the patient was found to be hypertensive and was referred to the emergency room. On admission she was asymptomatic but found to have a systolic blood pressure in the 200s. Renal artery stenosis or dissection was ruled out via CT angiogram of the abdomen and renal angiography by interventional radiology. No end organ complication was found. Serum renin was measured at 20, five times the upper limit of normal. Her blood pressure stabilized in the 130s with the initiation of amlodipine, and she was discharged the following day.
Discussion: Renal artery embolization (RAE), used to treat a wide array of renal pathology, is a procedure that involves disrupting renal blood flow. RAE can either be partial, in cases when functional areas of the kidneys need to be spared, or total. In patients receiving total RAE, the Juxtaglomerular apparatus (JGA) will likely be ablated as well, eliminating the initial step in the the Renin-angiotensin-aldosterone system (RAAS) and leaving the remaining kidney to compensate. In fact, this method has been extensively utilized in the treatment of refractory hypertension. Existing data regarding post procedural complications of RAE fail to demonstrate an increased risk of hypertension. Despite the lack of extensive evidence of this complication, there are several case reports suggesting that severe increases in blood pressure may occur, occasionally with fatal results. This seemingly paradoxical effect following a procedure that can be used in the treatment of hypertension is thought to be related to the degree to which the blood supply to the kidney is ablated. In patients that receive only partial embolization of the renal artery, the JGA may still be viable. Rarely, the residual JGA may increase RAAS activity in the setting of lower effective arterial blood volume, ultimately leading to hypertensive urgency and emergency. This mechanism is consistent with the increased renin activity noted in our patient. This side effect can present relatively late, up to weeks post procedure and can therefore be missed on routine post procedural screening.
Conclusions: Although rare, hypertensive urgency and emergency are potentially life-threatening complications of RAE. While patients typically do not receive long term monitoring post procedure, this condition may present up to weeks following embolization as evident in this case. With this in mind, patients require frequent and long-term blood pressure monitoring following RAE, even in the absence of prior hypertension, to prevent this potentially life-threatening complication. This condition should also be included on the differential for any patient presenting with hypertension post RAE.