Sebastian Ewen asks questions to Christian Ott, first author of " Ruling out secondary causes of hypertension " article published in EuroIntervention Journal Supplement on Resistant Hypertension Treatments, May 2013.
In the majority of hypertensive patients, no particular cause for abnormal blood pressure is evident (primary or essential hypertension). In contrast, in the minority of patients with secondary hypertension a specific underlying cause is responsible for the elevated blood pressure. The prevalence of secondary hypertension is higher in patients with resistant hypertension than in the general hypertensive population and increases with age. The list of secondary forms of hypertension is long and prevalence of the individual causes of secondary hypertension varies. Hence, this review divides them into two categories: common causes and rare causes. If appropriately diagnosed and treated, patients with a secondary form of hypertension might be cured, or at least show an improvement in their blood pressure control. Consequently, screening for secondary causes of hypertension plays an essential part in the care of patients with arterial hypertension. If the basal work-up raises the suspicion of a secondary cause of hypertension, specific diagnostic procedures become necessary, some of which can be performed by primary care physicians, while others require specialist input.
Sebastian Ewen: Do you screen every patient with elevated blood pressure for hypertension of secondary causes?
Christian Ott: An extensive work-up of all patients with hypertension is not necessary and would require immense human and technical resources. However, all patients should undergo initial baseline screening for secondary causes of hypertension. This screening can be based on medical history, clinical features, a physical examination, and distinct routine blood and urine tests (see for example 2013 European Society of Hypertension / European Society of Cardiology (ESC/ESH) guidelines 1 ). In contrast, hypertension of secondary cause can be indicated in treatment resistant hypertension, early or late onset as well as sudden onset or worsening of hypertension and in patients with disproportional organ damage to the supposed duration of hypertension. If the basal work-up raised the suspicion of a secondary cause of hypertension, specific diagnostic procedures become necessary.
Sebastian Ewen: Is a screening for conn´s syndrome (hyperaldosteronism) valid under a hypertensive therapy including interfering drugs of the renin-angiotensin-system?
Christian Ott: This topic has a long history of debate. For safety reasons (all) interfering antihypertensive medication can´t be removed in patients with treatment resistant hypertension. Complex tables were published showing the different effects of antihypertensive drugs on aldosterone and/or renin levels, resulting in a confounding shift of the aldosterone-renin ratio (ARR). However, with the exception of aldosterone antagonists and/or a direct renin inhibitor, which has to be stopped in any case, the potentially effect is within the range of maximal 15 – 20%, meaning that nevertheless in many cases aldosterone level and ARR are far away from pre-specified commonly used thresholds for biochemical evidence of hyperaldosteronism. Only in these cases, where ARR and aldosterone are nearby the thresholds, confirmatory test has to be performed.
To improve in general the sensitivity of ARR testing conditions should be optimized (i.e. collection in the morning after patients have been out of bed for at least 2 hours in seating position for at least 5 – 15 min). Moreover, patients should have unrestricted dietary salt intake, and hypokalemia should be ideally corrected 2 .
Sebastian Ewen: Do you perform a polysomnography in every patient who fulfilled the criteria of resistant hypertension and describes a daytime lack of energy?
Christian Ott: According to the 2013 ESC/ESH guidelines 1 it remains an unanswered question whether patients with treatment resistant hypertension should be systematically screened. However, in the joint recommendations by the ESH, by the Euopean Respiratory Society (ERS) and by the members of European COST ACTION B26 on obstructive sleep apnea (OSA) 3 it is proposed that if in addition to objective findings (e.g. treatment resistant hypertension), clinical symptoms (not only, but including increased daytime sleepiness or daytime fatigue) are apparent, at least overnight polygraphy should be recorded.
Although the BP reduction may be very modest due to nasal continuous positive airway pressure (nCPAP), it should be kept in mind that untreated (severe) OSA is proposed as an additional and independent risk factor, for cardiovascular diseases.
Sebastian Ewen: What is a therapeutic alternative for non-steroidal anti-inflammatory drugs (NSAID) to avoid drug-related hypertension?
Christian Ott: Acetaminophen can be an effective oral analgesic drug for mild to moderate pain. The use of weaker opioids (e.g. tramadol) can be considered for treatment in refractory pain. In patients with chronic inflammatory diseases (e.g. rheumatoid arthritis) anti-inflammatory agents may more effective in pain relief. Therefore, where NSAIDs are still necessary, an effective low as possible dose should be prescribed, since a dose-related effect on blood pressure is assumed. Moreover, if a swift to non-NSAIDs was not successful, administration of low dose glucocorticoids may be considered for a limited time in order to cope the pain and inflammation. Preferentially, underlying disease modifying therapy should be initiated or intensified.
Moreover, it should clearly be outlined that pain management is a multimodal approach. For example, the Osteoarthritis Research Society International (OARSI) recommendations for the management of hip and knee osteoarthritis point out that optimal management of OA requires a combination of non-pharmacological and pharmacological modalities 4 .
1 Mancia G, Fagard R, Narkiewicz K, Redon J, Zanchetti A, Bohm M, Christiaens T, Cifkova R, De Backer G, Dominiczak A, Galderisi M, Grobbee DE, Jaarsma T, Kirchhof P, Kjeldsen SE, Laurent S, Manolis AJ, Nilsson PM, Ruilope LM, Schmieder RE, Sirnes PA, Sleight P, Viigimaa M, Waeber B, Zannad F. 2013 esh/esc guidelines for the management of arterial hypertension: The task force for the management of arterial hypertension of the european society of hypertension (esh) and of the european society of cardiology (esc). J Hypertens . 2013;31:1281-1357
2 Funder JW, Carey RM, Fardella C, Gomez-Sanchez CE, Mantero F, Stowasser M, Young WF, Jr., Montori VM. Case detection, diagnosis, and treatment of patients with primary aldosteronism: An endocrine society clinical practice guideline. J Clin Endocrinol Metab . 2008;93:3266-3281
3 Parati G, Lombardi C, Hedner J, Bonsignore MR, Grote L, Tkacova R, Levy P, Riha R, Bassetti C, Narkiewicz K, Mancia G, McNicholas WT. Position paper on the management of patients with obstructive sleep apnea and hypertension: Joint recommendations by the european society of hypertension, by the european respiratory society and by the members of european cost (cooperation in scientific and technological research) action b26 on obstructive sleep apnea. J Hypertens . 2012;30:633-646
4 Zhang W, Moskowitz RW, Nuki G, Abramson S, Altman RD, Arden N, Bierma-Zeinstra S, Brandt KD, Croft P, Doherty M, Dougados M, Hochberg M, Hunter DJ, Kwoh K, Lohmander LS, Tugwell P. Oarsi recommendations for the management of hip and knee osteoarthritis, part ii: Oarsi evidence-based, expert consensus guidelines. Osteoarthritis Cartilage . 2008;16:137-162
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