Techniques of Renal Arteriography Subhash Banerjee, MD UT Southwestern Med. Ctr & VA North Texas Health care; Dallas, TX Indications For Renal Artery Angiography & Revascularization • Persistent hematuria of unresolved cause • Detection of renal tumor vacularity, venous invasion embolization • Suspected renal artery stenosis (RAS) • Suspected transection of the renal artery (penetrating injury) • Detection of inflammatory conditions, aneurysm or AVM • Evaluation of renal vascular anatomy of prospective donors • Evaluation of postoperative renal transplantation • Diagnosis of thrombosis revealed by renal venography • Collection of a sample of blood from the renal vein Prevalence of Atherosclerotic (A)RAS at Cardiac Catheterization Study, Year n ARAS > 30% (%) ARAS > 50% (%) Bilateral (%) Vetrovec et al, 1989 116 29% 23% 29% Harding et al, 1992 1302 29% 15% 28% Jean et al, 1994 196 33% 18% - Rihal et al, 2002 297 34% 19% 19% Weber-Mzell et al, 2002 177 25% 11% 26% Routine screening for RAS during coronary angiography NOT indicated White et al. Circulation.2006; 114: 1892-1895 Objectives of Renal Arteriography • • • • • Identify main as well as accessory vesels Localize site of stenosis or disease Determine type of disease (atherosclerotic or FMD) Provide hemodynamic significance Determine likelihood of a favorable response to revascularization • Identify associated pathology (aorta, renal mass etc) • Detect restenosis after percutaneous or surgical revascularization Proposed Algorithm for Diagnosis of RAS & Renal Artery Angiography Clinical suspicion of RAS/Indication for Revascularization MRA or CTA Renal artery duplex RAS + RAS - RAS + Angiography & intervention Captopril scintigraphy RAS - + - Angiography & intervention Technically good study Technically Poor study Technically good study Technically Poor study Stop Angiography Stop Angiography Strong clinical suspicion MRA: magnetic resonance angiography; CTA: Computed tomographic angiography Adapted from Vascular Medicine by Creager et al Stop Renal Artery Angiography • Catheter-based angiography remains the standard • Digital subtraction angiography (imaging matrix 1024 x 1024; 16” image II) • Oblique views of the aorta to visualize renal artery origins • Pressure gradients should also be obtained, whenever feasible • Imaging hardware and software: – Bolus chase, rapid image acquisition – Vessel diameter analysis, regional pixel shifting, image stacking – 3D reconstruction, angioscopic representation of DSA • Low osmolar iodinated contrast, gadolinium, CO2 angiography Renal Anatomy Between transverse processes of T12L3, left kidney more superior than right, upper poles oriented medially/posteriorly Renal Artery Angiography: Technical Considerations • Access: – Groin: ideally contra-lateral, long sheaths – Brachial: caudally angulated, aorto-iliac disease • Flush aortography with multi-side hole catheter (L1-L2) • Prior to selective renal artery catheterization an aortogram must be performed • Anterio-posterior & oblique views (visualization of renal artery origins) – Right: RAO 10ο-20ο, LAO 10ο – Left: LAO 0ο-15ο • Selective angiography of renal arteries – Shaped sheaths – Guiding catheters (Soft tip Omni, Cobra 2, Simmons, RDC etc) – Support guide-wire within aorta • Trans-lesional gradient (catheter, pressure wire) Non-selective Renal Angiogram: Early Division of Right Renal Artery Renal Angiography and Intervention: Transfemoral approach Renal Artery Stenosis & Complex Aortoiliac Disease Renal Artery Angiography: Brachial Approach • • Complications lower with femoral route Left brachial approach: – – – – – – – • Acute caudal angulation Inability to engage with reverse curve catheters Aorto-iliac PAD Infrarenal abdominal aneurysm graft in the femoral region rigid (non-elastic) arteries, tight calcified stenoses dilated abdominal aorta Complications with brachial approach greater – In patients with a small or diseased brachial artery – When a 7 French or larger sheath is required • • Use of a multipurpose catheter from left brachial approach Radial artery approach might be preferable over brachial because (lower complication & higher patient satisfaction) – Long sheaths and guidewires – Problems with catheter pushability & guidewire torque control – Sheath size is usually limited to 6 French Hessel et al. Radiology 1981; 138:273-281 Scheinert et al. Catheter Cardiovasc Interv 2001; 54:442-447 Renal Artery Angiography: Translesional Gradient • • • • • • RAS less than 50% in diameter are not significant “Gray zone” (50-70% diameter stenosis) Four French (1.35mm) catheter across 4 mm renal artery Pressure guide wire system Thermodilution technique to measure flow (Angioflow) Change in SBP could be a source of uncertainty: – When gradient is small – Simultaneous recording in the renal artery & aorta is preferable • 20 mm or greater systolic gradient results from a significant stenosis • 10% peak systolic gradient or >5% difference in MAP B. De Bruyne et al. JACC, Volume 48, Issue 9, Pages 1851-1855 Renal Artery Angiography • Anatomic variations in the renal vasculature occur in approximately 2540% of patients • Accessory, renal arteries are the most common arterial variation, with most of these branches supplying the lower pole of the kidney • Kidney position in the retroperitoneum is subject to variation as well Non-selective Renal Angiogram: Aberrant Renal Artery Below Right Renal Artery Non-selective Renal Angiogram: Accessory Renal Artery Below Right Renal Artery Non-selective & Selective Renal Angiography Accessory renal artery Aberrant renal artery Renal Arteriography • Conclusions: – Careful patient selection – Careful pre-procedural preparation & planning – Start with flush aortography – Selective renal arteriography – Anticoagulation primarily with UFH – Brachial/radial arterial access for challenging anatomy – Translesional gradient assessment of intermediate stenoses (with pressure wire) Clinical Clues to the Diagnosis of Renal Artery Stenosis (RAS) • Onset of HTN <30y or severe hypertension at >55y (Class I; LOE B) • Accelerated, resistant, or malignant hypertension (Class I: LOE C) • Unexplained atrophic kidney/size discrep. >1.5 cm (Class I; LOE B) • Sudden, unexplained pulmonary edema (Class I; LOE B) • Unexplained renal dysfunction (Class IIa; LOE B) • Development of new azotemia or worsening renal function after administration of an ACE inhibitor or ARB agent (Class I; LOE B) • Multivessel CAD or PAD (Class IIb; LOE B) • Unexplained CHF or refractory angina (Class IIb; LOE C) White et al. Circulation.2006; 114: 1892-1895