title: Renal frame count: a measure of renal flow that predicts success of renal artery stenting in hypertensive patients.
abstract: OBJECTIVE
  Renal artery (RA) stenting can improve control of hypertension yet predicting clinical response remains difficult. We sought to determine the role of the renal frame count (RFC) (number of angiographic frames for contrast to reach distal renal parenchyma after initial RA opacification) as a predictor of improvement in blood pressure (BP) after RA stenting.
  
  
  METHODS
  Renal flow was quantified in 68 consecutive patients (age 72.5 ± 9.1 years, 72% male) undergoing RA stenting for refractory hypertension (BP ≥ 140/90 mm Hg despite treatment with two or more antihypertensive medications) by measuring RFC pre-RA stenting. Significant renal artery stenosis (RAS) was defined as a stenosis ≥ 70% by visual estimation on angiography. Baseline and 6-month follow-up BP was recorded. Clinical response was defined by a drop in systolic blood pressure (SBP) >10 mm Hg on the same or fewer number of anti-hypertensive medications.
  
  
  RESULTS
  Patients with RFC > 30 had SBP reduction (43.2 ± 25.7 mm Hg vs. 30.1 ± 31.3 mm Hg, P = 0.067), diastolic blood pressure reduction (9.1 ± 19.0 vs. -0.2 ± 13.4 mm Hg, P = 0.02), and mean arterial pressure reduction (23.8 ± 19.4 vs. 11.8 ± 16.1 mm Hg, P < 0.001) compared to patients with RFC ≤ 30. Furthermore, baseline RFC >30 was associated with a higher rate of clinical response to RA stenting (93.5% vs. 73%, P = 0.027).
  
  
  CONCLUSIONS
  RFC can be used as a clinical predictor of response to RA stenting. RFC > 30 was associated with reduction in BP after RA stenting and was predictive of clinical response. RFC provides a useful intraprocedural tool in assessing the severity of RAS and predicts the likelihood of clinical response following RA stenting.
authors.affiliation: Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California, San Diego, California.
authors.forename: Jesse
authors.initials: J
authors.lastname: Naghi
authors.affiliation: Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California, San Diego, California.
authors.forename: Samhita
authors.initials: S
authors.lastname: Palakodeti
authors.affiliation: Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California, San Diego, California.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Ang
authors.affiliation: Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California, San Diego, California.
authors.forename: Ryan
authors.initials: R
authors.lastname: Reeves
authors.affiliation: Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California, San Diego, California.
authors.forename: Mitul
authors.initials: M
authors.lastname: Patel
authors.affiliation: Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California, San Diego, California.
authors.forename: Ehtisham
authors.initials: E
authors.lastname: Mahmud
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001783:Blood Flow Velocity; D001794:Blood Pressure / Q000187:drug effects; D003287:Contrast Media / Q000008:administration & dosage; D004359:Drug Therapy, Combination; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D005260:Female; D006801:Humans; D006978:Hypertension, Renovascular / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D012079:Renal Circulation; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015607:Stents; D016896:Treatment Outcome
chemical_list: D000959:Antihypertensive Agents; D003287:Contrast Media
keywords: hypertension; peripheral artery disease; renal artery stenosis; renal artery stenting; renal frame count