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Renovascular Disease: Core Curriculum

Renovascular Disease: Core Curriculum. Renal Artery Stenosis. Etiology + Pathophysiology Incidence Diagnosis Indications for Revascularization Treatment Options - Medical Therapy - PTA - Surgical Technical Considerations Complications Prognosis.

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Renovascular Disease: Core Curriculum

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  1. Renovascular Disease:Core Curriculum

  2. Renal Artery Stenosis Etiology + Pathophysiology Incidence Diagnosis Indications for Revascularization Treatment Options - Medical Therapy - PTA - Surgical Technical Considerations Complications Prognosis

  3. Causes of Ischemic Renal Disease • Atherosclerotic Renal Artery Stenosis • Fibromuscular dysplasia • Nephroangiosclerosis (HTN injury) • Diabetic nephropathy (small vessels) • Renal thromboembolic disease • Atheroembolic renal disease • Aortorenal dissection • Post renal transplant RAS • Renal artery vasculitis • Trauma • Neurofibromatosis • Thromboangiitis obliterans • Scleroderma #1 Renal Artery Stenosis #2 Fibromuscular Dysplasia

  4. Atherosclerotic Renal Artery Stenosis • Atherosclerosis accounts for approximately 90% of the cases of RAS and is the predominant lesion detected in patients >50 years of age • The presence and number of diseased coronary arteries predicts the likelihood of ARAS • RAS resulting from atherosclerotic disease is common in (18% to 20%) individuals undergoing coronary angiography 1 • RAS resulting from atherosclerotic disease is even more common (35% to 50%) in individuals undergoing peripheral vascular angiography for occlusive disease of the aorta and legs 2 1. Rihal et al Mayo Clin Proc 2002; 77: 309–316 2. Olin et al J Vasc Surg 2002; 36: 443–451

  5. Fibromuscular Dysplasia (FMD) • Unknown etiology • Second most common cause of RAS • Affects middle-aged women • More common in first-degree relatives and in the presence of the ACE-I allele. • Renal artery involvement is seen in 60% of cases - frequently bilateral compromise. • Progressive renal stenosis is seen in 37% of cases and loss of renal mass in 63% Grossmans “Catheterization” 7th Ed. pg. 562-603.

  6. Classic “string of beads” appearance of fibromuscular dysplasia. • Intravascular ultrasound (IVUS) with a 40-MHz catheter demonstrating multiple fine fibrous bands and foci of interband aneurysmal dilatation. • Translesional gradient measured between a 6Fr guide catheter placed in the aorta and a 4F glide catheter placed in the distal renal artery. A 60-mm Hg resting gradient is demonstrated. Grossmans “Catheterization” 7th Ed. pg. 562-603.

  7. Fibromuscular Dysplasia (FMD)Treatment • Balloon angioplasty alone: FMD localized within the main renal artery or its primary branches • Stenting: Reserved for failure or complications of balloon angioplasty • Surgery: FMD that involves multiple branch vessels or is associated with aneurysmal disease Grossmans “Catheterization” 7th Ed. pg. 562-603.

  8. Post-balloon angioplasty with a 4.5mm diameter balloon demonstrating improvement in the angiographic appearance. • Intravascular ultrasound (IVUS) confirms the postangioplasty improvement • Postprocedure IVUS demonstrates fracture of the fibrous bands, resulting in resolution of the gradient seen before the procedure. Grossmans “Catheterization” 7th Ed. pg. 562-603.

  9. Schematic of Pressor Mechanisms Identified in Renovascular Hypertension Garovic VD, Textor SC. Circulation 2005;112:1362-1374

  10. Renal Artery Stenosis Etiology + Pathophysiology Incidence Diagnosis Indications for Revascularization Treatment Options - Medical Therapy - PTA - Surgical Technical Considerations Complications Prognosis

  11. 70 60 50 40 30 20 10 0 Prevalence of Renal Artery StenosisMost Common Cause of 2o HTN 50-59% 30% 20% 15% 5-10% Aortography For PAD All HTN Pts >50 yrs With ESRD Pts with CAD Acc HTN Rihal et al Mayo Clin Proc 2002; 77: 309–316 Olin et al J Vasc Surg 2002; 36: 443–451

  12. Prevalence of Renal Artery Stenosis 834 patients undergoing ultrasound screening • Mean age of 77 years • Significant (>60%) RAS in 6.8% of the study cohort • 2 x as many men (9.1%) as women (5.5%, P=0.053) • RAS showed no association with ethnicity, even distribution among white (6.9%) and black (6.7%) participants • RAS was significantly and independently associated with increasing age, low high-density lipoprotein cholesterol levels, and increasing systolic blood pressure. Hansen et al J Vasc Surg 2002;36:443-51

  13. Severe Renal Artery Stenosis Multivariate Associations 837 patients undergoing screening angiography Buller CE et al JACC 2004: 43:1606

  14. Incidence of Renal Artery Stenosis at Cardiac Catheterization White, C. J. Circulation. 2006;113:1464-1473

  15. Approximately 50% of renal artery stenoses progress over time

  16. 141 ± 114 μmol/L 97 ± 44 μmol/L 97 ± 44 μmol/L Progression Of RASDisease progression is associated with a decline in renal function Patients with normal renal arteries at baseline Crowley JJ et al Am Heart Journal 1998;136:913

  17. Progression of Renovascular Disease Results in Renal Atrophy • 204 kidneys in 122 patients with RAS • 6 monthly serial duplex scanning • Defined as > 1cm reduction in length 2 year incidence of renal atrophy: Normal RA 5.5% < 60 % stenosis 11.7% > 60 % stenosis 20.8% Risk of atrophy increased by systolic hypertension (> 180mm Hg) and a high peak systolic velocity Caps et al, Kidney International, 1998

  18. 4 Year Mortality 1235 cath lab patients screened for RAS > 50% Multivariable Predictors Age Gender GFR (per 5 ml/min) SBP (per 5 mmHg) Abdominal or LE Disease Carotid Disease P Value 0.004 0.029 0.004 0.005 0.037 0.0007 OR 1.72 1.91 0.86 1.08 2.06 3.13 Conlon PJ et al, J Am Soc Nephrol 9:252;1998

  19. Renal Artery Stenosis Etiology + Pathophysiology Incidence Diagnosis Indications for Revascularization Treatment Options - Medical Therapy - PTA - Surgical Technical Considerations Complications Prognosis

  20. Garovic VD, Textor SCCirculation. 2005;112:1362-1374

  21. Renal Artery ObstructionThe Dilemma of Diagnosis Atherosclerosis, hypertension and renal insufficiency exist and co-exist commonly. When there is renal artery stenosis: • Is it the cause of hypertension? • Is it the cause of renal insufficiency? • Will treatment improve either? • Will treatment prevent deterioration?

  22. www.Cardiosource .com. ACC/AHA Guidelines

  23. www.Cardiosource .com. ACC/AHA Guidelines

  24. Noninvasive diagnostic modalities Renal Artery Ultrasound • Body habitus dependent • Operator dependent • May miss accessory arteries • No additional anatomical information • Physiological information • Allows post intervention surveillance

  25. 74 y/o man with difficult to control HTN

  26. Duplex Assessment of RAS

  27. Power Doppler image of a stenosis of right RA. The arrows indicate the stenosis. Manganaro et al. Cardiovascular Ultrasound 2004 2:1

  28. Noninvasive diagnostic modalitiesDigital Subtraction Angiography 40 y/o woman with well controlled HTN

  29. Noninvasive diagnosis: MRA • Identifies accessory renal arteries • Provides additional anatomical information • No radiation • No nephrotoxic contrast • Allows 3-D reconstruction • May “overcall” lesions • Looses accuracy in distal segments (FMD) Mild (30%) left RAS and severe (90%) right RAS in 70-year-old man Fenchel, M. et al. Radiology 2006;238:1013-1021

  30. Normal renal arteries in a 61 y/o man Severe stenosis of left renal artery in a 72 y/o man Herborn, C. U. et al. Radiology 2006;239:263-268

  31. 40 y/o woman with well controlled HTN

  32. 74 y/o man with difficult to control HTN Motion artifact

  33. Renal Artery Stenosis Etiology + Pathophysiology Incidence Diagnosis Indications for Revascularization Treatment Options - Medical Therapy - PTA - Surgical Technical Considerations Complications Prognosis

  34. Reasons to Revascularize Atherosclerotic Renovascular Disease • Treat Symptoms • Prevent Future Illness • Lower BP • Preserve Renal Function • “Bystander” Effects • - Prevent Death • - Prevent MI • - Prevent CHF • - Prevent CVA

  35. Indications for Revascularization of RAS • 1. Resistant hypertension • Failure of medical therapy despite full doses of 3 drugs, including diuretic • - Compelling need for ACE inhibition/angiotensin blockade with angiotensin-dependent GFR • 2. Progressive renal insufficiency with salvagable kidneys • Recent rise in serum creatinine • Loss of GFR during antihypertensive therapy (e.g., ACEI) • Evidence of preserved diastolic blood flow (low resistive index) • 3. Circulatory congestion, recurrent “flash” pulmonary edema • 4. Refractory congestive heart failure with bilateral renal artery stenosis Circulation 2005;112:1362-1374.

  36. Who Will Benefit: Renal Resistive Index • Reflection of intrarenal vascular surface area and resistance • Calculated using Doppler U/S • Resistive Index • [1-(EDV/PSV)]x100 • 4950 patients underwent U/S calculation of renal resistive index • 138 RAS patients treated • Followed for improvement in BP and Cr Radermacher et al NEJM. 2001;344:2244-49

  37. Outcomes Predicted By RRI Radermacher et al NEJM. 2001;344:2244-49

  38. Renal Revascularization • Useful when: • Renal artery stenosis is SEVERE, and... • Renal function is “salvageable” • Preserved size • Preserved intrinsic vasculature (“low” RI) • Not useful when: • Renal artery stenosis is not severe • Renal function is “unsalvageable” • Unknown: • Prophylactic use • Value of screening • Role of atheroembolization / Protection

  39. Renal Artery Stenosis Etiology + Pathophysiology Incidence Diagnosis Indications for Revascularization Treatment Options - Medical Therapy - PTA - Surgical Technical Considerations Complications Prognosis

  40. Goals Of Renal Artery Revascularization • Improve control of hypertension • Preserve or restore renal function • Treat other potential adverse physiologic effects of severe renal artery stenosis (congestive heart failure, recurrent flash pulmonary edema, and angina)

  41. I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III Pharmacological Treatment of Renal Artery Stenosis • ACE inhibitors are effective medications for treatment of hypertension associated with RAS. • Calcium-channel blockers are effective medications for treatment of hypertension associated with unilateral RAS. • Beta-blockers are effective medications for treatment of hypertension associated with RAS. • Angiotensin receptor blockers are effective medications for treatment of hypertension associated with unilateral RAS. ACC/AHA Guidelines

  42. Renal stent placement is indicated for ostial atheroesclerosic RAS lesions that meet the clinical crietria for intervention. Balloon angioplasty with “bail-out” stent placement if necessary is recommended for fibromuscular dysplasia lesions. I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III Catheter- Based Interventions for RAS ACC/AHA Guidelines

  43. Renal Artery Stent Placement Ostial atheroma 2 mm into aorta Stent with protrusion into aortic lumen Zeller T. Journal of Interv Card 18 (6), 497-506.

  44. 1188 patients, mean follow up 16 months Hypertension cured 20% Hypertension improved 49% Renal function improved 30% Renal function stabilized 38% 69% 78% Renal Artery Stenting: Results Published series before 1998 Leertouwer et al Radiology 2000, 216 78-85

  45. Renal Artery Stenting Studies • Meta-analysis of 349 pts in 8 clinical series - Hypertension improved in 56%; cured in 10% - Renal artery function improved in 27%; stabilized in 38% - Restenosis occurred in 16% - Major complications in 4.9 Palmaz JC et al J Vasc Intervent Radiol 1998;9:539-43 • DRASTIC Trial - 106 patients treated with PTA or medical therapy - Although no difference in outcomes, stenting reserved for “bailout”, 44% of medical therapy crossed over to PTA due to HTN, occlusion seen in 16% of medical treated patients Van Jaarsveld BC et al. N Engl J Med 2000; 342: 1007-1014

  46. Percent Procedure Success Restenosis Superiority of renal artery stent compared with balloon angioplasty for procedure success and restenosis rates White CJ Circulation 2006;113:1464-1473

  47. Surgery for Renal Artery Stenosis • Endarterectomy • Aortorenal bypass • Extra-anatomic bypass using hepatorenal, splenorenal, ileorenal, or superior mesenteric artery – renal anastomosis.

  48. Atherosclerotic RAS in combination with pararenal aortic reconstructions (in treatment of aortic aneurysms or severe aortoiliac occlusive diseease. Fibromuscular dysplastic RAS with clinical indications, especially those exhibiting complex disease that extends into the segmental arteries and those having macroaneurysms. Atheroeclerotic RAS and clinical indications for intervention, especially those with multiple small renal arteries or early primary branching of the main renal artery. I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III I I I IIa IIa IIa IIa IIb IIb IIb IIb III III III III Surgery for Renal Artery Stenosis ACC/AHA Guidelines

  49. Renal Artery Stenosis Etiology + Pathophysiology Incidence Diagnosis Indications for Revascularization Treatment Options - Medical Therapy - PTA - Surgical Technical Considerations Complications Prognosis

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