Renovascular hypertension

Dr Saad Al Shohaib KAUH

Incidence Renovascular disease is an important

and treatable cause of hypertension and renal impairment

It accounts for less than 1% of mild and moderate hypertension but may be seen in 10 to 40% of hypertensive crises

Renal disease is the comments cause of secondary hypertension

Target population for screening Acute rise in serum creatinine shortly after ACE

inhibitor therapy or unexplained rapid deterioration in renal function with minimal proteinuria

Moderate to sever hypertension in a patient with diffuse atherosclerosis

Hypertension in a patient with a symmetric renal size or hypokalemia

Moderate to severe hypertension in patients with recurrent episodes of acute (flash) pulmonary edema or otherwise unexplained congestive heart failure

Screening tests Intravenous pyelogram – There

are two major findings on intravenous pyelography that suggest the presence of unilateral ischemia: a decrease in renal size; and delayed caliceal appearance time when compared to the contralateral kidney

Screening Plasma renin activity – The baseline

plasma renin activity is elevated in only 50 to 80 percent of patients with renovascular hypertension

. The predictive value can be increased by measuring the rise in the plasma renin activity one hour after the administration of 25 to 50 mg of captopril

screening Renogram following ACE

inhibitor the predictive value of radioisotope

scanning can be increased by enhancement with captopril.

Screening Duplex Doppler ultrasonography

has the advantage of providing both anatomic and functional assessment of the renal arteries

Time consuming Operator dependent and difficult It can be done after captopril

Recommendations In high risk patients may use subs

traction angiogram as an initial test MR angiography is a non invasive

alternative test particularly if combined with doppler

Postma CT Joosten FB etal AM J Hyper sept 1997

In one study 38 patients with hypertension were screened using MRA and subs traction angiogram

One patient was excluded 14 patients had renal artery steno sis

12 patients had more than 50% stenosis

All these stenos is were recognized by MRA

There were one false positive case by MRA

MRA has 100% sensitivity and 96% specifity

Postma CT; Joosten FB; Rosenbusch G; Thien TSO - Am J Hypertens 1997 Sep;10(9 Pt 1):957-63

Conclusion MRA has a great accuracy in

detecting clinically significant main renal artery stenos is

Significant stenosis Hem dynamically significant stenos only

should be corrected Good response to ACE inhibitors suggest the

presence of significant stenos increased Renal vein renin may suggest a

significant stenosis but this is not widely used Other tests used to screen for renovascular

hypertension would help to determine significance

CRF AND ISCHAEMIA Ischemia might be responsible for

decreased renal function in a significant number of patients with renal failure in older patients

Correction of ischemia would improve renal function

Renal insufficiency Unexplained progressive renal failure Benign urine sediment with sever renal

impairment Unilateral very small kidney with renal impairment Testing should be done with progressive renal

impairment uncontrolled pressure and recurrent pulmonary edema

Contrast may induce further renal damage

Ischemia and CRF Presence of diffuse atherosclerosis

make Reno vascular disease more likely

There is usually minimal proteinuria Uncontrolled hypertension Flash pulmonary edema Progressive renal failure with benign

urine sediment

Renovascular disease The earlier the intervention the

better the prognosis Contrast may cause further renal

damage Reversibility is more likely in

patients with rapid deterioration of renal function

Conclusion Renovascular hypertension should

be suspected in hypertensive crisis uncontrolled hypertension patients with hypokalemia and high BP

Presence of unequal kidney size or flash pulmonary edema make the diagnosis more likely

Conclusion The homodynamic effect of ِِACE

inhibitors help in the diagnosis reversibility of renal function as well as the significance of the stenosis

Uncontrolled hypertension in a patient with diffuse atherosclerosis particularly if associated with renal impairment is highly suggestive of renovascular hypertension

Conclusion MRA with Doppler ultrasound are good

screening tests Revascularization should be done in

hem dynamically significant stenosis Correction of significant bilateral

stenosis may improve renal failure and help to avoid dialysis in selected cases

Thank you