Cp 47 Renovascular HPN Flashcards
refers to rise in arterial pressure definitely induced by reduced renal perfusion
Renovascular HPN
pressure gradient between aorta and poststenotic renal artery required before measurable renin release occurs
At least 10-20mmhg
luminal obstruction “critical” lesions before hemodynamic effects can be detected
70-80%
Hypertension not ANG II dependent
Bilateral RAS or solitary kidney
Effects of blockade of RAS in Unilateral RAS
- Reduced arterial pressure
- Enhanced lateralization of diagnostic tests
- Glomerular filtration rate (GFR) in stenotic kidney may fall
effect of bloacled of RAS in bilateral RAS
- Reduced arterial pressure only after volume depletion
- May lower GFR
Plasma renin elevated
Unilateral or bilateral RAS?
Unilateral RAS
Explain the adaptive mechanism to reduced renal perfusion
What happens to the cortical? Medulla?
Reduced blood flow —> collaterals develop
Chronic reduced BF in medulla—> activate adaptive maintenance of tissue perfusion
More severe—> oberwhelm adaptive mechanisms—> cortical hypoxia —> tubular atrophy (due to necrosis and apoptosis)
Tubular atrophy can be reversible (“hibernating state”)
Reduced blood flow a tivated numerous pathways of vascular and toasue injury including increase in?
ANG II
ET
Oxidative stress
What happens to the Nitric oxide in reduced perfusion?
How about ANG II?
Reduced perfusion leads to diminished shear stress distal to the stenosis —> decrease NO production post stenosis and inc ANG II and TXA—> intrarenal vasoconstriction
A direct consequence of reduced perfusion in the postetonic kidney (histo)
Progressive rarefaction—> tubular collapse
Late event and usually reflects severe loss of the GFR
Glomerulosclerosis
No-reflow phenomenon
Worsen during reperfusion phase
Reflect vascular damage and Acitvation of leukocytes - primed to obstruct distal capilliaries
Is a risk facor for disease progression of FMD
Smoking
What is rhe most common subtype of FMD ?
Appearance?
Medial fibroplasia
String of beads
Usually Affected arteris in FMD
Renal arteries 65-75% (bias on right renal artery)
Cerebral a. 25%
Location of FMD lesions
Location of ARAS
- Away form the origin
Midportion
First bifurcation - Near the origin
Can occur anywhere
Risk factors for ARAS
Strongly assoc with?
- Incrwasing age
- Elevated cholesterol
- Smoking
- Hypertension
- Preexisting HPN
Cardiovascular lipid risk
Diabetes
Smoking
Abnormal renal function
Syndrome associated with Renovascular HPN
1.Early or late-onset hypertension (<30 yoars or >50 yoars)
2. Acceleration of treated essential hypertension
3. Deterioration of renal function in treated
essential hypertonsion
4. Acute renal fallure during treatment of hypertension
5. Flash pulmonary edema
6. Progressive renal fallure
7. Refractory congestive cardiac failure
** symptoms 5-7 are MC In patients with BILATERAL disease
MC presentation of RAS
Progressive worsening of preexisting HPN
Strongest predictors of RAS
Other clincial predictors?
- Age and crea
Recent progression
Other vascular dss (eg claudication)
Abdominal bruit
Flash pulmonary edema arise in?
HPN with left ventricular systolic function ( preserved)
Sudden rise in arterial pressure impairs cardiac function due to rapidly developing diastolic dysfunction
Those with declining renal function have a poor survival rate regardless of intervention, the strongest predictor of which is
Low baseline GFR
Potential benefit of revascularization ia greatest when serum crea is
<3mg/dL
Provides measurements of localized velocities of blood flow and characteristics of renal tissue
Doppler
Used to monitor restejosis and target vessel patency
Doppler
Primary criteria for renal artery studies (doppler)
- Peak systolic velocity above 180cm/sec
And/or relative velocity above 3.5 as compared wirh the adjacent aortic flow
Dampening of waveforms in Doppler labeled as parvus and tardus ar signs of
Indirect sign of upstream vaacular occlusive phenomena
Resistive index of ______ was assoc with a >90% faborable BP response and stable to improved renal function
< 80
Normal study excludes rebovascular HPN
Captopril renography
Allows calculation of single kidney GFR
Nuclear imaging
Enhances the release of renin from the stenotic kidney
Measurement of captopril stimulated renin activity
Lateralization predictive of
improvement in blood pressure with revascularization
Measurement of renal vein renin activity
Measures the level of activation of the renin-angiotensin system
Measurement of peripheral plasma renin activity
Excellent accuracy for evaluation of in-stent restenosis
Computed Tomography Angiography
