michigan hypertension core curriculum - State of Michigan

The kidney is both a target as well as the cause/contributor to hypertension. 13
Evaluation of kidney function in hypertensive patient has several purposes. First,
to ascertain the level of kidney function which is a key determinant in the JNC 7 risk
stratification scheme and also to define the nature and activity of nephropathy. 1
The diagnosis of renal disease can be made by multiple diagnostic tests
including the urinanalysis and calculation of an estimated glomerular filtration rate (GFR)
utilizing the MDRD equation utilizing the serum creatinine. Utilizing serum creatinine
without estimating GFR may underestimate the presence of renal insufficiency,
especially in women. 13
Chronic kidney disease is defined as GFR < 60ml/min/1.73m 2 or the presence
of albuninuria (>300mg/d or 200mg/g creatinine [spot urine albumin:crea ratio]). 9 The
urinary albumin:creatinine ratio is easily determined on random, spot urine collections
and is typically all that is need to quantify urinary protein excretion; it is rarely necessary
to order timed 24 hour urine collections. On the other hand, some practitioners will
utilize the urine protein:crea ratio at higher levels of urinary protein excretion. 9
The risk for CVD rises dramatically at incrementally lower levels of kidney
function. CKD is an independent risk factor for CVD and, persons with CKD manifest a
high prevalence of hypertension. CVD risk also exhibits a continuous relationship with
albuminuria which is at least in part a reflection of higher BP levels at higher levels of
albuminuria. 10
Peripheral artery disease (PAD)
Patients should be screened for a past history of peripheral vascular disease,
previous revascularization or signs and symptoms of PAD. Peripheral pulses should
be palpated and auscultation of carotids, abdomen and femoral artery performed
to determine the presence of bruits. 10,14,15 In patient with signs or symptoms of PAD
critical stenosis of one or both renal arteries should be suspected especially in the
setting of resistant hypertension as well as in those with hypertension plus depressed
kidney function. 1,2 The optimal treatment (medical therapy versus medical therapy plus
angioplasty/stenting)for critical renal artery stenosis has yet to be determined. 10
Retinopathy
Hypertensive retinopathy is a condition characterized by a spectrum of retinal
vascular signs in people with elevated BP. 16 Numerous studies confirm the strong
association between the presence of signs of hypertensive retinopathy and elevated BP. 5
Opthalmologic evaluation is considered standard practice in evaluating hypertensive
patients and is supported by previous and current JNC reports. 1
Hypertensive retinopathy was first described by Dr. Marcus Gunn in the late 19 th
century. In 1939 Keith Wagener and Barker showed that these signs were predictive of
death in hypertensive patients. Their report classified hypertensive retinopathy into four
groups of increasing severity. 16
Though opthalmoloscopic evaluation is a central part of the initial and ongoing
medical examination of hypertensive patients, direct opthaomoscopic examination is
highly unreliable with high variability in observed findings both within a single observer
over time as well as between observers at a given point in time. 4,5 Nevertheless, the
noted high variability does not negate performing careful opthalmoscopic evaluations
during the initial evaluation of the the hypertensive patient as well as periodically during
their ongoing care.
On the basis of photographic studies, hypertensive retinopathy is common in
people over 40 years of age, even in those without a history of hypertension; this is likely
NKFM & MDCH 159