White coat hypertension: understanding the concept and examining the significance

Because the concept of white coat hypertension is evolving, a variety of definitions appear in the literature. There has also been continuing debate as to whether white coat hypertension is a benign clinical condition or is associated with increased hypertensive complications. This paper summarizes and evaluates the literature on white coat effect/hypertension, with a focus on the following aspects of the concepts: (1) alternative definitions, (2) prevalence and predictors, (3) prognostic significance, and (4) implications for clinical practice. The evidence suggests that white coat hypertension is not a harmless phenomenon. It is frequently associated with increased target-organ damage and often coexists with other cardiovascular risk factors. The extent of the presence of other risk factors may determine the risks associated with white coat hypertension. It is important for clinicians to understand the concept, learn to diagnose it properly, and develop strategies for evaluating risk levels so that patients receive the proper treatment.     

Current options for the treatment of resistant hypertension

Patients with resistant hypertension are those who have uncontrolled blood pressure despite use of three or more antihypertensive medications, or those who require four or more medications to achieve control. When evaluating resistant hypertension it is important to rule out pseudoresistant hypertension that may result from factors including poor blood pressure measurement technique and the white coat effect. Potential contributing factors should be identified and reversed if possible, including obesity, excess alcohol intake and use of interfering medications such as NSAIDS, sympathomimetics and oral contraceptives. Modification of lifestyle factors such as weight loss, sodium restriction and physical activity is paramount for treatment success. Secondary causes of hypertension are common in this patient group and, therefore, appropriate screening tests should be carried out as necessary. Pharmacologic therapy is centered on combination therapy of medications from different mechanisms of action, especially diuretics, which are essential in maximizing antihypertensive effects. The role of mineralocorticoid antagonists is expanding, especially in patients with obstructive sleep apnea and obesity where aldosterone excess may be implicated. Finally, when appropriate, specialist referral may facilitate blood pressure reduction and the ability to meet target blood pressure goals.     

Management of difficult-to-control hypertension

Hypertension is a primary risk factor for heart disease and stroke, the first and third most common causes of death in the United States. The National Health and Nutrition Examination Survey (NHANES) revealed an increase in awareness of hypertension from 51% to 73%, and, among persons with hypertension, the treatment rate has increased from 31% to 55% (from 1976-1980 vs 1988-1991). Of importance, the rate of those achieving goal blood pressure (< 140/90 mm Hg) has only improved from 10% in NHANES-II (1976-1980) to 29% in NHANES-III (1988-1991). Thus, more than 70% of persons with hypertension in whom good blood pressure control has not been achieved are termed "difficult hypertensives." Failure to achieve treatment blood pressure goals of less than 140/90 mm Hg is usually attributed to the presence of resistant hypertension, a resistant physician, secondary causes of hypertension such as renovascular disease, medication adverse effects, or a nonadherent patient. A practical understanding of the pathophysiology of resistant hypertension, appropriate screening techniques for secondary forms of hypertension, and alternative management strategies for a chronic disease such as hypertension can result in treatment goals being achieved in most difficult hypertensives.     

运动应激试验前后血清皮质醇和IL-6水平与白大衣性高血压的关系

目的探讨运动应激试验前后血清皮质醇和IL-6水平的变化及其与白大衣性高血压的关系。方法选取2014年1月至2016年8月该院收治的白大衣性高血压患者48例作为研究组,选取同期普通高血压患者30例作为普通组和30例健康体检者作为对照组。3组均在空腹状态,在功率200 W的自行车上以蹬车2min后间歇5min再重复运动直至极度疲劳,完成运动应激试验。检测比较3组运动前、运动后即刻及运动后3h的血清皮质醇和IL-6水平及平均动脉压(MAP),分析血清皮质醇和IL-6水平对白大衣性高血压的诊断价值及其与患者MAP的关系。结果与对照组比较,研究组和普通组运动前后的血清皮质醇和IL-6水平及MAP均升高;与普通组比较,研究组运动前后的血清皮质醇和IL-6水平及MAP均升高(P0.05)。研究组运动后即刻及运动后3h的血清皮质醇和IL-6水平及MAP均较运动前升高(P0.05)。ROC曲线分析结果显示,运动应激试验前后血清皮质醇和IL-6水平对白大衣性高血压的诊断价值良好,其中以运动后即刻血清皮质醇和IL-6水平联合诊断白大衣性高血压的价值最优。Pearson线性相关分析结果显示,运动应激试验前后血清皮质醇和IL-6水平与白大衣性高血压MAP均呈正相关(r分别为0.844、0.802,P0.05)。结论运动应激试验前后血清皮质醇和IL-6水平对白大衣性高血压的诊断价值良好且与其血压水平相关,可能作为白大衣性高血压诊断和病情评估的参考指标。     

Improving patient outcomes with ambulatory blood pressure monitoring in elderly with hypertension

PURPOSE: The purpose of this article is to review the current knowledge regarding ambulatory blood pressure monitoring (ABPM) use in clinical practice and to provide example cases for its use in a hypertension (HTN) specialty clinic. DATA SOURCES: Published research trials, medical literature, and cases from the Center for Senior Hypertension. CONCLUSIONS: The knowledge of ABPM benefits to using ABPM are substantial and improves the care and management of many conditions, including white coat HTN, white coat normotension, resistant, borderline, episodic, paroxysmal HTN, and finally orthostatic hypotension. Third-party payers only cover ABPM for "white coat" HTN. IMPLICATIONS FOR PRACTICE: This article reviews previous studies and explains the benefit to changing our current practice to match the knowledge we have gained through research through case studies.     

Treatment resistant hypertension

Treatment resistant hypertension is defined as a blood pressure not achieving a goal blood pressure (<140/90 mm Hg) with a combination of three or more antihypertensive drugs. There are several causes for patients not responding to antihypertensive medication. One of the major reasons is noncompliance to the treatment, often because of real or perceived side effects or because of a great number of medications and frequent dosing. Exogenous substances, most frequently nonsteroidal anti-inflammatory drugs, and, often not recognized, over-the-counter medications containing ephedrine or pseudo-ephedrine, can reduce the effect of antihypertensive drugs. Obesity and obstructive sleep apnea oppose antihypertensive drug effects by several mechanisms but predominantly by an increase in the activity of the sympathetic and renin-angiotensin-aldosterone systems. White coat hypertension as a cause of treatment resistance is suspected if there is no target organ damage or if the patients complain of symptoms of hypotension during antihypertensive treatment. Secondary forms of hypertension, although comprising only approximately 5% of patients with treatment resistant hypertension, are important to identify because they may represent a curable form of hypertension.     

Hypertension

The current JNC-VI criteria for diagnosis and classification of hypertension are discussed. The laboratory evaluation of both essential and secondary hypertension is examined, and recommendations are made in this regard. Finally, the complications and treatment of essential hypertension and the causes and management of resistant hypertension are discussed.     

Management of hypertension in children and adolescents

Secondary causes of hypertension are more frequent in children than in adults; however, essential hypertension does occur in the young. The decision to search for secondary causes rests on the age of the child, the severity of hypertension, the presence of clues in the history or physical examination, and the family history. If nonpharmacologic measures fail to control hypertension and if acute hypertension is not present, a stepped-care approach is suggested.     

Clinical applications of ambulatory blood pressure monitoring: the white coat syndrome

The estimation of an individual's true blood pressure by conventional clinical measurement is subject to a number of errors, stemming partly from the inherent variability of blood pressure, and also from the white coat syndrome, which is an elevation of blood pressure limited to the clinic setting. This may occur in about 20% of patients with mild hypertension, and is hypothesized to be a learned or conditioned response. Ambulatory monitoring may help to identify such patients. Other potential clinical applications of the technique include evaluation of patients with resistant hypertension, with excessively labile blood pressure, or with autonomic insufficiency, which may be characterized not only by hypotensive episodes, but also by hypertensive episodes during the night. An unresolved question is the definition of the upper limit of normal ambulatory pressure, which is required before ambulatory monitoring finds wide clinical acceptance.     

Resistant hypertension: diagnosis and management

The incidence of resistant hypertension, the failure to reduce blood pressure below 140/90 mm Hg, despite the use of 3 antihypertensive medications at optimal doses including a diuretic, is estimated to be less than 5% of the hypertensive population. Resistant hypertension increases the risk of stroke, myocardial infarction, congestive heart failure, and renal failure. Evaluation of the patient with resistant hypertension should include 24-hour ambulatory blood pressure monitoring or home measurements and a limited search for secondary causes. Treatment should focus on optimizing the drug regimen in a logical way, based on the patient's comorbidities and tolerability. Long-acting, well-tolerated once-daily medications are preferred, and the regimen should include in sequence a diuretic, beta-blocker, angiotensin-converting enzyme/angiotensin receptor-blocker inhibitors, and a calcium-channel blocker. This article reviews the definitions and causes and provides specific recommendations for the evaluation and management of patients with this life-threatening condition.     

Evaluation and pharmacologic approach to patients with resistant hypertension

Patients are diagnosed as having resistant hypertension when they have blood pressure readings that remain above goal despite the concomitant use of 3 optimally dosed antihypertensive agents from different classes, with 1 of the agents being a diuretic. Prior to diagnosing a patient as having resistant hypertension, it is important to document adherence and exclude white-coat hypertension, inaccurate measurement of blood pressure, and secondary causes of hypertension (eg, aldosterone excess). After determining resistance, optimization of the medication regimen is essential. Combination strategies, which might include dual renin-angiotensin-aldosterone blockade with spironolactone as 1 agent, have been proven successful. This article focuses on the safety and efficacy of spironolactone when added to an optimized 3-drug regimen. Additionally, the use of spironolactone in chronic kidney disease and obstructive sleep apnea complicated by resistant hypertension is discussed. These 2 clinical entities are frequently accompanied by resistant hypertension and are indications for the use of spironolactone as well.     

Doctors in a white coat--what do patients think and what do doctors do?

Patients and general practitioners in northern Norway were asked their opinion on the doctors' use of a white coat in the consultation. 51.9% of the patients wanted their doctor not to wear a white coat, whereas 11.7% of the doctors never wore one. 5.7% of the doctors' staff members never wore a white coat. The patients' preferences were to some extent related to their own doctors' use of a white coat, and there was a significant increase in the demand for a white coat with increasing age of the patients.     

Pheochromocytoma and fibromuscular hyperplasia

We have described a case which documents two possible surgical correctable causes for hypertension in a 55-year-old white man. Preoperative renal arteriograms and renal vein renin determinations suggested the possibility of renal artery stenosis due to fibromuscular hyperplasia. At operation, a pheochromocytoma was found in the left suprarenal area. The presence of two unusual causes for hypertension in a single patient suggests that more than one remediable cause of hypertension should at least be considered in a given hypertensive patient.     

"White coat" hypertension

The literature concerning the problem of "white coat" hypertension is reviewed. The diagnosis of such hypertension is important for valid treatment policy in hypertensive patients. This diagnosis is based primarily on the data of 24-h blood pressure monitoring.     

Initial evaluation of patients with hypertension: an office procedure

Traditionally the initial evaluation of a patient with high blood pressure has focused on exluding secondary correctable causes of hypertension. Such all-inclusive evaluations are expensive, time-consuming, and expose the patient to some risk. A complete history, physical examination, and relatively simple laboratory procedures such as CBC, urinalysis, SMA-6 and 12, and ECG yield sufficient information to detect damage to target organs caused by elevated blood pressure and to exclude the presence of secondary causes fairly adequately. In that small number of patients in whom clues for correctable causes of hypertension are uncovered, or if patients fail to respond to appropriate treatment for essential hypertension, a more extensive evaluation can be undertaken.     

Clinical use of laboratory tests for the identification of secondary forms of arterial hypertension

The prevalence of secondary hypertension can be underestimated if appropriate tests are not performed. The importance of selecting patients with a high pre-test probability of secondary forms of hypertension is first discussed. The laboratory tests currently used for seeking a cause of hypertension are critically reviewed, with emphasis on their operative features and limitations. Strategies to identify primary aldosteronism, the most frequent form of secondary hypertension, and to determine its unilateral or bilateral causes are described. Treatment entails adrenalectomy in unilateral forms, and mineralocorticoid receptor blockade in bilateral forms. Renovascular hypertension is also a common, curable form of hypertension, that should be identified as early as possible to avoid the onset of cardiovascular target organ damage. The tests for its confirmation or exclusion are discussed. The various tests available for the diagnosis of pheochromocytoma, which is much rarer than the above but extremely important to identify, are also described, with emphasis on recent developments in genetic testing. Finally, the tests for diagnosing some rarer monogenic forms and other renal and endocrine causes of arterial hypertension are explored.     

Pediatric ophthalmology attire: should we wear a white coat?

The purpose of this study was to determine if patients and their families in a pediatric ophthalmology and adult strabismus clinic have a preference regarding physician and staffattire. Patients and/or parents were invited to complete a three-question survey. Respondents were queried based on three types of attire preference: white coat, professional clothing without white coat, or casual attire without white coat. Two hundred twenty-seven patients participated. Of the patients queried, no preference for any one style of physician attire was found. These results do not support previous studies indicating significant preference for white coats.     

EVALUATING THE USE OF A SEMIAUTOMATED CUFF-OSCILLOMETRIC SPHYGMOMANOMETER IN THE HYPERTENSION CLINIC

SUMMARY Measuring blood pressure in the clinic setting is confounded by ‘white coat’ hypertension, observer bias and digit preference. In this study a semiautomatic blood pressure measuring device (the UA-751) was tested for its use as a reliable assessment of blood pressure and improved patient management in the hypertension clinic. Blood pressures were recorded in 156 patients and compared with physicians' readings measured using a standard mercury sphygmomanometer. The mean blood pressure differences between the two methods showed that the device gave consistently higher readings for both systolic (1.4-3.6 mmHg) and diastolic (3.6-3.8 mmHg) pressure, whether it was used before or after physician consultation. No reduction in ‘white coat’ hypertension was thus apparent. There was considerable variability between recordings made by the two methods on the same individual. Digit preference was apparent with physician readings, with zero recorded in 57.8% of systolic readings compared with 12.2% using the machine. Different management decisions would have been taken in 20 (13.6%) patients had the UA-751 recordings been used. The device is thus of no value in patient management in the setting of the hypertension clinic.     

Secondary causes of hypertension

Secondary hypertension is the presence of a specific condition known to cause hypertension, which may be the primary cause or a contributing factor in a patient who already has primary hypertension. Although uncommon, it may cause major morbidity for a subset of patients. This article provides an overview of the range of secondary causes, including key clinical features and appropriate diagnostic and treatment options. Selection of patients for testing should incorporate historical and clinical clues, previous treatment course, and comorbidities. Decisions regarding the extent of secondary evaluation require consideration of the likelihood of diagnosis, the patient's overall health status and prognosis, and balancing the risks of intervention against the risks of missing a diagnosis. Referral is advised when these risks seem prohibitive or if there are questions regarding the selection of the most optimal studies or the extent of intervention to pursue when blood pressure remains uncontrolled.     

Renovascular hypertension: a rare cardiovascular manifestation of the Ehlers-Danlos syndrome

The association of the Ehlers-Danlos syndrome with many cardiovascular abnormalities is well known. To our knowledge, however, renovascular hypertension due to renal arterial aneurysms has not previously been reported in patients with this disease. We describe a patient with type IV Ehlers-Danlos syndrome who had multiple systemic and bilateral renal arterial aneurysms and hypertension. The hypertension could have been related to compression of renal tissue or arteries (or both) by the large aneurysms, associated stenoses, or small peripheral renal infarctions. A review of all patients in whom the Ehlers-Danlos syndrome had been diagnosed at our institution between 1967 and 1985 revealed that 4 of the 200 patients had hypertension. Three of these patients, and probably all four, had secondary causes of hypertension: Cushing's syndrome, renal insufficiency, or renovascular hypertension (in the present case). We conclude that hypertension is rare in patients with the Ehlers-Danlos syndrome and that, if present, it most likely is secondary hypertension. A thorough search for secondary causes of hypertension should be undertaken in these patients.