Angiotensin-converting Enzyme Inhibitor Radionuclide Renogram – A Non-invasive Tool to Suspect Renovascular Hypertension

A 42-year-old male who is a known smoker and alcoholic presented to the vascular surgery department with complaints of gripping pain in both lower limbs over the past 6 months. He is undergoing treatment for refractory hypertension (BP 200/130 mmHg) despite optimum medication comprising calcium channel blocker, beta-blocker, and diuretics over 6 years. His serum creatinine was 1.6 mg/dl while the blood sugar, electrolytes, cholesterol, and liver function tests were within normal limits. He is also being treated for chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR] = 27 ml/min/1.73m2 at diagnosis) and possible bilateral renal artery stenosis (RAS) was considered. Contrast-enhanced computed tomography showed complete occlusion of the right renal artery with contracted right kidney and 70–80% occlusion at the origin of the left renal artery [Figure 1a and b]. Pan angiogram showed a significant peripheral vascular disease of both iliac arteries while the subclavian, carotid, and upper limb vessels were normal. He was treated for one episode of flash pulmonary edema 9 months ago. At that time, his echocardiography showed concentric LVH and global LVEF of 58%. There was no regional wall motion abnormality. ECG showed ST depression in II, III, and aVF, and therefore, he was started on statins also, along with aspirin. At the time of referral to our institution, his global LVEF was 43%. We received him in our department to study the functional significance of RAS with 99mTechnetium-DTPA renogram with angiotensin-converting enzyme inhibitors (ACEIs). The patient was prepared as per the Society of Nuclear Medicine and Molecular Imaging guidelines for baseline and ACEI renogram (2 days protocol).[1] He was allowed to continue his medication during the study period. On day 1, baseline renogram was performed by giving intravenous injection of 100 MBq of 99mTc-DTPA in 1.0 ml saline through an intravenous cannula. Sequential dynamic and periodic static images of the abdomen Abstract