Untitled

Noninterventional
and Medical Management
Hypertension
Management in
PAD Patients
BY JAMES A.M. SMITH, DO
Hypertension (HTN) can be defined as persistent hypertrophy and mitral regurgitation) is easily assessed by elevation in blood pressure exceeding the ideal this noninvasive test, it is a very compelling argument that of 130/90 mm Hg (130/85 in diabetics). There patients require more aggressive treatment of their BP.
are, however, many scenarios in which it is less When coronary artery disease, PAD, or bruits are discovered than clear whether a patient with HTN needs to be treated.
or identified in any vascular territory, the issue of BP must Each of us has encountered the patient who says, “My pres- be addressed because HTN accelerates the atherosclerotic sure is always high when I come to the doctor’s office. At home, my pressure is fine.” That person requires evaluation Although secondary causes of HTN are present in <10% and follow-up to determine if there is a blood pressure (BP) of patients, the first step in treating essential HTN has been the restriction of dietary sodium because excess salt results HTN is one of the major risk factors for cardiovascular in volume retention, which may exacerbate HTN in many disease and poses a risk in other vascular territories; there- individuals. This requires considerable education regarding fore, it is critical to evaluate the patient from a broad per- dietary sodium because the diet in Western societies is very spective regarding cardiovascular risk. Genetic predisposi- high in sodium content, much of which is “hidden” and tion to vascular disease is especially important when com- unknown to the consumer. It is well known that canned pounded with other risk factors: HTN, smoking, elevated soups and fast food (increasingly consumed by the older lipids, insulin resistance, sedentary behavior, or previous vas- population), as well as many restaurant meals, snack foods, cular territory insult, such as myocardial infarction (MI), and luncheon meats, are very heavily salted, yet few of our congestive heart failure (CHF), stroke, hypertensive patients take time to analyze what they eat on a daily basis.
retinopathy, left ventricular hypertrophy, and peripheral Diastolic HTN frequently occurs in the obese population artery disease (PAD). It should be emphasized that BP con- and is multifactor, including high sodium consumption, vol- trol is a key element in minimizing the likelihood of cardio- ume expansion, diastolic cardiac dysfunction in insulin vascular death and morbidity in these patients. Interestingly, resistance syndrome, and sedentary behavior. This group Wong et al reported that 75% of patients with systolic HTN also includes individuals with obstructive sleep apnea, an had inadequate control. More importantly, although 89% of ever-increasing number in Western society. These people patients with strokes were treated for HTN, only 35% of may present with systolic HTN, diastolic HTN, or they may those patients had their BP controlled to adequate levels be in “sympathetic overdrive,” which is HTN with resting (≤140/90 mm Hg), and subsequently, there was a one in six Systolic HTN is prevalent in older populations due to a decrease in large vessel compliance, salt and fluid retention, H T N A N D I T S C AU S E S
and left ventricular dysfunction. In certain individuals, sym- In patients who insist that their BP is never high unless pathetic overdrive—resting tachycardia with increased sys- they are in the doctor’s office, an echocardiogram is very temic vascular resistance—can result in HTN, which acceler- useful to predict target-organ effects of sustained HTN.
ates the potential for cardiovascular morbidity, especially Because negative remodeling of the heart (ie, left ventricular 52 I ENDOVASCULAR TODAY I APRIL 2008
HTN in patients with cardiac or renal disease invariably Frequently lacking in these medical regimens are patients has a combination of risk factors. Idiopathic (essential) HTN taking ownership of their condition. They often fail to make is by far the common denominator in the population at risk adequate lifestyle modifications to help control their disease for cardiovascular disease. However, these patients may process. As many of these patients are >50 years old, their progress to require the addition of multiple medications for lifestyles are ingrained such that they find it nearly impossi- BP control. When this happens, a physician may suspect ble to exercise, lose weight, eat a healthy diet, and favorably that other factors, such as renal artery stenosis (RAS) or influence their disease. A common argument is genetics, decreased large-vessel compliance, may be contributing.
“My dad was big, my uncles, aunts, and mother had dia- RAS is predominantly due to atherosclerotic (macro- betes, etc.” Thus, the patient has the foregone conclusion arterial) disease, although in younger individuals (<35 years), that, “There is nothing I can do about the cards I was dealt.” a separate etiology, fibromuscular dysplasia of the renal This attitude permeates our society, and unless we as physi- arteries, should be considered. The groups of patients with cians intervene earlier, the idea of inevitability continues to intrinsic renal disease, glomerulonephritis, interstitial nephri- become an insurmountable obstacle resulting in cardiovas- tis, and vasculitis represent a smaller proportion of the hypertensive population. Because these hypertensive One startling trend in the US is the ever-increasing preva- patients are less common, this discussion focuses primarily lence of diabetes, which correlates with obesity in our popu- on individuals in the risk pool for systemic atherosclerosis, lation.4 Patients who claim that, “My HgA1c is good” tend patients >50 years with multiple cardiovascular risk factors. to ignore the fact that any diagnosis of insulin resistance(prediabetes, type II diabetes) correlates with the presence H T N T R E ATM E N T I N T H E PAD PAT I E N T
of cardiovascular disease. Thus, cardiovascular disease can PAD represents atherosclerosis of the lower extremities, manifest as a macroarterial insult (MI, stroke, symptomatic and HTN is often a common denominator in these patients.
PAD, RAS with renal insufficiency, HTN) or as a microvascu- Because HTN is a risk factor for MI, stroke, limb claudica- lar complication, such as retinopathy, nephropathy, diastolic tion, and renal failure, treatment of HTN is an essential ele- dysfunction, peripheral neuropathy, lacunar stroke, claudica- ment for treating any of these conditions. tion, and potential limb loss. Diabetes accelerates vascular Current therapy in patients with a history of MI includes disease, and once the diagnosis is made, the patient must beta blockade, angiotensin receptor blockade with or with- understand the seriousness of potential cardiovascular com- out angiotensin-converting enzyme inhibition, diuretics, and antiplatelet regimens. Calcium channel blockers have bothantiarrhythmic and antihypertensive effects as well, and the Factors to Consider When Selecting a Treatment Plan
majority of these patients are on some combination of Key points in the assessment of HTN are the presence of these medications. Central alpha-adrenergic inhibitors may target organ damage, such as left ventricular hypertrophy, also be used. Thus, we treat these patients with volume stroke, and proteinuria. Any finding that suggests the pres- (sodium) depletion, diuretics, renin inhibition, sympathetic ence of PAD, such as claudication and carotid or abdominal inhibition, and calcium blockade while attempting to slow bruits, should heighten the acuity of the clinician’s need to the progression of their cardiovascular disease.
treat the patient’s HTN and other risk factors. Pohl et al In patients with resistant HTN who do not have RAS, found that atherosclerotic renal artery disease progressed in hyperaldosteronism is recognized as the most common eti- 44% (37/85) of patients; 16% (14/85) of patients progressed ology. In this setting, a plasma aldosterone-to-renin ratio should be measured even if the serum potassium level is We see patients over a wide spectrum of disease process- normal. A ratio >20 has sufficient sensitivity and specificity es. One patient may present with an acute MI as the first to serve as an effective screening test for hyperaldostero- symptom of cardiovascular disease, whereas another indi- nism. Confirmation with a 24-hour urine test for aldos- vidual who had an MI 4 years before is seen for a routine terone excretion confirms the diagnosis. Values of urinary physical. The common denominator is systemic atheroscle- aldosterone exceeding 12 mg/24 hours with urinary sodium rosis, and we as clinicians know that there are factors that >200 mEq/24 hours reflect primary aldosteronism.2 favor progression and others that tend to slow the progres- Medical therapy with mineralocorticoid receptor antago- sion of the disease process. Although we physicians are not nists, such as spironolactone and eplerenone, offers a first always model patients ourselves, it behooves us to set a line of therapy in these patients, especially when they are good example by our lifestyles, appropriate exercise, and not good surgical candidates. Laparoscopic adrenalectomy dietary behavior with judicious counseling. It is also critical should be considered in patients with a unilateral adenoma that we use the resources available to us and provide this whose BP cannot be controlled adequately.3 information to our patients to permit them to make APRIL 2008 I ENDOVASCULAR TODAY I 53
Potential Reasons for Nonreferral
First, some nephrologists may not believe that percuta- neous transluminal angioplasty with or without stents hasbeen beneficial. The indications for percutaneous translu-minal angioplasty with stenting have not been welldefined. Current indications include difficult-to-controlBP in patients with >70% unilateral or bilateral stenosis,azotemia caused by significant RAS, uncompensated CHFor flash pulmonary edema in patients with bilateral RAS,or decreasing renal mass (atrophy) caused by unilateral orbilateral RAS that has been assessed by serial imaging. In the DRASTIC study, Van Jaasveld et al studied 106 patients with RAS exceeding 50% and a serum creatininelevel of 2.3 micrograms per deciliter or less. These patients Figure 1. This 79-year-old patient with bilateral RAS had a
were also required to have a diastolic BP of ≥95 mm Hg hostile aorta and severe multidrug-resistant HTN. Because of
despite treatment with two antihypertensive medications insulin-dependent diabetes mellitus and severe CAD, she was
or a serum creatinine level increase of >0.2 micrograms not a candidate for surgical revascularization. She had two
per deciliter during treatment with an angiotensin-con- hospitalizations for “flash” pulmonary edema in the preced-
verting enzyme (ACE) inhibitor. The patients were moni- ing 3 months and ultimately underwent bilateral renal artery
tored for 12 months, and the investigators found no sig- percutaneous transluminal angioplasty with stents. She lived
nificant differences in systolic and diastolic BP, daily drug 4 additional years with no subsequent admissions for CHF
doses, or renal function between the angioplasty without and did not require dialysis.
stents group and the drug therapy group. They concludedthat in the treatment of patients with HTN and RAS healthy decisions. The psychology of medicine is an enor- >50%, angioplasty had little advantage over antihyperten- mous part of our daily practice, and our relationship with sive therapy. Patients were excluded from the DRASTIC patients is critical to modifying the natural history of sys- study if they had proven secondary HTN from other caus- temic atherosclerosis. We are fortunate to have excellent es (cancer, CHF, unstable CAD). Only two patients in the pharmacology available, with the potential for even better angioplasty group received renal artery stents, while two drugs on the horizon.6 However, unless we can convince additional patients underwent surgical revascularization patients to take ownership of their disease, make changes in for failed angioplasty and in one patient whose HTN per- lifestyles, and reinforce good behavior, we will continue to sisted (diastolic BP ≥95 mm) after 3 months. At 12 expend a very large amount of our health care resources on months, 48% (23/48) of the angioplasty patients had at putting out fires and crisis intervention in cardiovascular least 50% stenosis of the treated artery, but none had care. Of those issues that may be successfully treated, our total occlusion. In the drug therapy randomized group, justification may be for the prevention of stroke, MI, renal 86% (43/50) underwent angiography at 12 months.
failure, or lowered mortality rates. The prevention of renal Seventy-two percent (31/43) of these patients had steno- failure usually is accomplished by interventional means in sis ≥50%, and the stenosis had progressed to total occlu- patients with severe bilateral RAS or unilateral disease to a sion in 9% (4/43). This study raised even more questions regarding the treatment of RAS, and the data were signifi-cantly flawed by the fact that stents (the current standard H OW O F T E N D O N E P H RO LO G I S T S R E F E R
of care) were not used. The patients who underwent sur- R A S PAT I ENTS ?
gical revascularization confound not only the data but On a monthly basis, I teach a course on angiography and also suggest that the premise of endovascular therapy for peripheral vascular intervention. The students include cardi- preservation of renal size (mass) is correct. Although there ologists, radiologists, vascular specialists, and, increasingly, was no significant benefit in BP control between the two cardiovascular surgeons and general surgeons who are learn- groups, a selection bias against patients with CHF who ing peripheral vascular intervention techniques. I ask them, were not included in the study may have actually favored “Do nephrologists refer patients for RAS?” Invariably, the intervention with angioplasty and stents had they been answer is either “never” or “very seldom.” These responses raise the question as to why this is the case. As I see it, there Second, some nephrologists may not pursue the diag- nosis with fervor. Some HTN experts may claim that the 54 I ENDOVASCULAR TODAY I APRIL 2008
gold standard, the renal duplex scan, is “not that accurate” C O N C L U S I O N S A N D P R O V O C AT I O N S
or is “technically difficult.” Although it is true that the The treatment of HTN in the cardiovascular patient technical difficulty is an issue in large patients and some- population remains a significant clinical challenge. In times requires a bowel preparation, it is widely viewed as fact, it needs to be one of the highest priorities in pre- the most accurate test with absolutely no potentially venting the progression of cardiovascular disease in pre- adverse biologic effects. In the proper hands, it is the gold viously diagnosed target organs or undiagnosed other standard (short of angiography) in diagnosing RAS. The vascular territories. Because the treatment of HTN often duplex scan combines real-time imaging of the kidney requires a multidrug regimen, the physician must factor with pulsed Doppler interrogation of the renal arteries.
in a number of concerns—such as the frequency of dose Thus, it provides information about kidney size, contour, administration, cost, and side effects—that weigh heavi- and drainage, while also providing physiologic data about ly on the clinical decision-making process. In addition, and perhaps just as important, is the fact that the This raises other questions: “With an exam such as the patient has systemic atherosclerosis, a potentially termi- renal duplex scan available, why is it not more widely nal disease, and medication is only a part of the overall available, and why do not vascular specialists, and espe- management of this condition. The patient must take cially nephrologists, insist upon excellence when providing ownership of his condition while the physician provides this test?” The fact remains that the renal duplex scan, counseling, encouragement, and the psychological sup- when performed by a registered vascular technologist, is port necessary to help him make significant lifestyle the most specific, cost-effective test available to our patients with HTN who are in a high-risk category for ath- Whether we are doing a good job in treating HTN erosclerotic disease. Otherwise, the clinician is forced to remains in question, and recent data suggest that we can rely on contrast imaging with computed tomography or do much better.1 Various types of physicians treat car- magnetic resonance angiography, or a standard contrast diovascular patients, and it is important to use the avail- angiogram. Knowing the value of this completely nonin- able resources to aggressively pursue a target BP of vasive test, it behooves all vascular laboratory directors to <140/90 mm Hg and to monitor disease progression. In insist that their registered vascular technologists are profi- some cases, endovascular intervention provides at least cient in performing a renal duplex scan. a palliative solution, but results need to be monitored.
Third, nephrologists believe that medical therapy is just This includes monitoring of the BP and patient lifestyle, as good or better than intervention. This argument may periodic assessment of glomerular filtration rate and reflect local expertise or lack thereof or the false assump- serum creatinine, renal duplex surveillance after an inter- tion that we are doing a better job of controlling HTN vention, and even more proactive evaluations of hyper- than we actually are. (See the National Health and tensive patients with this highly effective technology. ■ Furthermore, if the only alternative were progression to James A.M. Smith, DO, is the Founder and Director of the need for dialysis, why would one not aggressively find the River City Cardiac and Vascular Institute, in Wichita, and treat these patients with percutaneous transluminal Kansas. He is board certified by the American Board of angioplasty and stents? One might draw the conclusion Vascular Medicine, Intervention. Dr. Smith may be reached on the behalf of the patient that a dialysis lifestyle is toler- at (316) 462-1070; [email protected]. able. However, the time commitment, comorbidities, costof transportation, inconvenience to family members and 1. Wong N, Lopez V, L’Italien G, et al. Inadequate control of hypertension in US adults with patients, and burden of chronic illness must be consid- cardiovascular disease comorbidities in 2003-2004. Arch Intern Med. 2007;167:2431-2436.
2. Nishizaka MK, Pratt-Ubunama M, Zaman MA, et al. Validity of plasma aldosterone-to- ered. No one wants to be on dialysis unless every poten- renin activity ratio in African American and white subjects with resistant hypertension. Am J Fourth, nephrologists may be afraid of losing control of 3. Pimenta E, Gaddam KK, Oparil S. Mechanisms and treatment of resistant hypertension. J their patients after referral to the vascular specialist. This Clin Hypertens. 2008;10:239-244.
4. Celik T, Iyisoy A, Kursaklioglu H, et al. Comparative effects of nebivolol and metoprolol on argument is sound in that most of us as physicians believe oxidative stress, insulin resistance, plasma adiponectin and soluble P-selectin levels in that we can do as good a job at treating BP as another hypertensive patients. J Hypertens. 2006;24:591-596.
specialist or even the primary care physician. In fact, the 5. Pohl MA, Novick AC. Natural history of atherosclerotic and fibrous renal artery disease: National Health and Nutrition Exam Survey suggests that clinical implications. Am J Kidney Dis. 1985;4:A120-130.
6. Weber MA, Bakris GL, Giles TD, et al. Beta-blockers in the treatment of hypertension: new this mentality may have credibility because only 35% of data, new directions. J Clin Hypertens. 2008;10:234-238.
patients who had strokes were subsequently treated with 7. Van Jaarsveld BC, Krijinen P, Pieterman H, et al. The effect of balloon angioplasty on hypertension in atherosclerotic renal artery stenosis. NEJM. 2000;342:1007-1014.
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