Ischemic nephropathy

1. Ischemic nephropathy Presenter : DR. Kushal. D. P

2. Synonyms “Azotemic renovascular disease” or or ischemic renal disease (IRD)

3. Definition The term “ischemic nephropathy” (IN) means impairment of renal function beyond occlusive disease of the main renal arteries Azotemic renovascular disease” is other term coined by some authors suggesting that loss of renal viability may not directly be associated with impairment in oxygenation of renal tissue as less than 10% of the blood is needed to fulfill the metabolic requirement

4. Renovascular hypertension is defined as a syndrome of elevated BP (systolic and/or diastolic) produced by any condition that interferes with arterial circulation to the kidneys. Of the conditions that may produce the syndrome of RVH, main vessel RA stenosis is by far the most common. The two major causes of main renal artery disease are fibromuscular dysplasia (FMD) and atherosclerotic renal vascular disease (ASRVD).

5. Epidemiology M ean age of patients with IN to be 68.7 years of which 97.4% were hypertensive, 69.8% smokers and 62.95% having hypercholesterolemia, evidences of atherosclerosis at other vascular beds in 82% of these patients, 65% showing peripheral a r teriopathy. The prevalence of IN has been found to be increasing with age and was found to be responsible for 5%-22% cases of renal dysfunction in patients above 50 years. 12% progressing to ESRD with an average decline in GFR of 8 mL/min

6. In patients undergoing angiography of the peripheral or coronary circulation, ASRVD is found in 11% to 42%. One population-based study of 870 patients older than 65 screened with RA duplex ultrasound found a 6.8% prevalence of ASRVD, defined as greater than 60% stenosis. Autopsy series report an overall prevalence of 4% to 20%, with progressively higher rates for those older than 60 years (25% to 30%) and 75 years (40% to 60%).

7. RA stenosis from ASRVD contribute s to the decline in renal function in 15% to 22% of patients reaching ESRD. The prevalence of clinically apparent renovascular FMD is estimated at 4 in 1000 , with a lower prevalence of cerebrovascular involvement of 1 in 1000. S creening angiography in potential kidney donors suggest that FMD observed in 3% to 6% of individuals. FMD has a female predilection( 90%). FMD is common er in whites than in blacks. T he mean age of onset of hypertension 43 years . Familial FMD occurs in approximately 10% of patients and autosomal dominant inheritanc e

8. Etiology & pathogenesis

9. Clinical features When to suspect? Onset of hypertension at >55 years of age Accelerated, treatment resistant or malignant hypertension Unexplained difference in kidney size >1.5 cm Recurrent unexplained pulmonary edema Worsening renal function after ACE inhibitor treatment Unexplained renal dysfunction Evidence of peripheral artery disease or CAD

10. ASRVD ( atherosclerotic renal vascular disease ) Atherosclerotic plaque often arises in the first or second centimeter of the renal artery or may extend from the aorta into the renal ostium. Predictors of ASRVD include a history of hypertension, presence of renal functional impairment . coexisting vascular or coronary artery disease, the presence of abdominal bruits, and a history of smoking. RA lesions are bilateral in 20% to 40% of such patients.

11. Fibromuscular dysplasia (FMD) Fibromuscular dysplasia (FMD) is a noninflammatory, nonatherosclerotic arteriopathy and the second most common cause of RVH. It usually involves the middle to distal renal artery or branches. The vascular distribution of FMD involves primarily the renal and cerebral arteries. Renal arteries are involved with FMD in 65% to 70% of cases. Bilateral RA disease is seen in 25% to 35% of adult cases.

12. NATURAL HISTORY ASRVD typically progresses over 2 to 5 years. Over 4 to 5 years, 6% to 16% of stenoses advance to occlusion. Progression is most likely in patients with more than 60% stenosis. Follow-up studies of patients with incidentally detected, highgrade RA stenosis (>70%) treated medically indicate that fewer than 10% required later revascularization for intractable hypertension. Another report noted that few patients with incidental RA stenosis progressed to ESRD over follow-up of 8 to 9 years.

13. Retrospective analyses report 3-year to 5-year mortality rates of 30% to 35% in patients with RA stenosis, largely caused by cardiovascular events or cerebrovascular accident. In follow-up of more than 1200 patients who underwent coronary and renal angiography, patients with RA stenosis had a 65% 4-year survival versus 85% for those without RA stenosis at catheterization. The 5- and 10-year survival rates for patients reaching ESRD caused by IRD are as low as 18% and 5%, respectively

14. It appears that up to 27% of patients may demonstrate angiographic progression of FMD when serial studies are undertaken. This appears to be limited to younger patients, with few patients developing new or progressive lesions after age 50 years. FMD rarely causes ESRD unless hypertension remains uncontrolled or thrombosis or dissection of the renal vessel results in renal infarction. Renal cortical atrophy has been reported in more than half ofpatients with untreated FMD

15. DIAGNOSIS

16. DOPPLER USG PSV > 180: >60 % STENOSIS EDV > 150: > 80 % STENOSIS ACCELERATION TIME : > 0.08-0.1 RESISTIVE INDEX

17. TREATMENT The main aim of treatment is to reduce cardiovascular mortality, to improve or stabilize renal function and blood pressure control. Treatment options include medication, surgical reconstruction and transluminal angioplasty with or without stenting.

18. Medication having proven role in preventing cardiovascular mortality including statins, renin angiotensin antagonists, and low dose aspirin are also effective in secondary prevention of IN patients who received reninangiotensin antagonists had a lower incidence of death and cardiovascular events, a higher incidence of AKI and a lower incidence of long-term dialysis than patients who did not receive such treatment

19. R evascularization should be considered in RAS with rapid worsening of renal function or resistant HTN (4 or more antiHTNsive agents especially in the setting of CHF or recurrent flash pulmonary edema). When the kidney size is <8.0 cm long or the RI is >0.80, there is little chance of BP improvement or recovery of GFR.

20. A ngioplasty has a better blood pressure outcome and is thus more strongly indicated in fibromuscular dysplasia than in atherosclerotic RAS. The standard procedure for revascularization involves balloon angioplasty, and, if necessary, stent placement. For patients with a macroaneurysm (an aneurysm larger than 2 cm in diameter) or with complex lesions that affect segmental arteries,surgical reconstruction is indicated

21. Recent studies

22. The study c onclu ded that revascularization may be of benefit in patients with anatomically significant RAS who present with rapidly deteriorating renal function, especially in the presence of severe bilateral ARVD or <1 g/day proteinuria.

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