White-Coat Effect Is Uncommon in Patients With Refractory Hypertension

Unattended versus conventional blood pressure measurements in hospitalized hypertensive patients

BACKGROUND

This study aims to compare the differences between unattended and conventional blood pressure measurements in hospitalized hypertensive patients.

METHODS

In fall of 2019, hypertensive patients at Ruijin Hospital underwent two rounds of unattended and conventional (nurse-monitored) blood pressure measurement. Both rounds used the same electronic blood pressure monitor with measurements taken three times, 30 s apart. Comparison was made using intra-class correlation coefficients, Bland-Altman plots, paired t -tests, etc.

RESULTS

Among the 92 subjects in the study, the median age was 50 years old, with women accounting for 33.7%. Among the subjects, the median duration of hypertension was 8.0 years. The prevalence of diabetes, coronary heart disease, and stroke were 26.1%, 5.4%, and 6.5%, respectively. Whether unattended or conventional measurements were taken first, the average blood pressure measured first was slightly higher than the one measured later, but the difference was within 1-2 mmHg. Except that the average DBP during the round of conventional blood pressure measurements was significantly reduced by 1.6 mmHg compared to the conventional DBP, there were no other significant differences. Subgroup analysis by age, gender, BMI, and diabetes showed no significant difference in blood pressure measurement results between unattended and conventional methods.

CONCLUSION

No significant difference was observed between unattended and conventional methods of blood pressure measurement in hospitalized hypertensive patients. Unattended blood pressure measurement can be adopted as the current standard for blood pressure management in hospitalized patients.

Target Blood Pressure Values in Ambulatory Blood Pressure Monitoring

INTRODUCTION

2018 ESC/ESH guidelines have recommended 24-h ambulatory blood pressure monitoring to assess hypotensive therapy in many circumstances. Recommended target blood pressure in office blood pressure measurements is between 120/70 and 130/80 mmHg. Such targets for 24-h ambulatory blood pressure monitoring lacks.

AIM

We aimed to define target values of blood pressure in 24-h ambulatory blood pressure monitoring in hypertensive patients.

METHODS

Office blood pressure measurements and 24-h ambulatory blood pressure monitoring data were collected from 1313 hypertensive patients and sorted following increasing systolic (SBP)/diastolic (DBP) blood pressure in office blood pressure measurements. The corresponding 24-h ambulatory blood pressure monitoring to office blood pressure measurements values were calculated.

RESULTS

Values 130/80 mmHg in office blood pressure measurements correspond in 24-h ambulatory blood pressure monitoring: night-time SBP/DBP mean: 113.74/66.95 mmHg; daytime SBP/DBP mean: 135.02/81.78 mmHg and 24-h SBP/DBP mean: 130.24/78.73 mmHg. Values 120/70 mmHg in office blood pressure measurements correspond in 24-h ambulatory blood pressure monitoring: night-time SBP/DBP mean: 109.50/63.43 mmHg; daytime SBP/DBP mean: 131.01/78.47 mmHg and 24-h SBP/DBP mean: 126.36/75.31 mmHg.

CONCLUSIONS

The proposed blood pressure target values in 24-h ambulatory blood pressure monitoring complement the therapeutic target indicated in the ESC/ESH recommendations and improves 24-h ambulatory blood pressure monitoring usefulness in clinical practice.

The Influence of Factors such as Anxiety on the White Coat Effect during the Treatment of Patients with Hypertension

Background

The white coat effect is observed in many patients with hypertension, but its mechanism is still unclear and anxiety is often thought to be a key point.

Methods

A total of 544 patients who met the inclusion criteria were recruited through outpatient clinics. Three months after systematic treatment, the office blood pressure and ambulatory blood pressure monitoring (ABPM) were examined. Patients who reached the ABPM standard were divided into white coat effect (n = 112) and control (n = 432) groups according to the results of the office blood pressure. The degree of anxiety in the two groups was evaluated using the Self-rating Anxiety Scale (SAS) and the Beck Anxiety Scale (BAI). Differences in anxiety, gender, age, number of antihypertensive drugs, cost per tablet and marital status were analyzed.

Results

There was no significant difference in the degree of anxiety between the white coat and control groups, with mean SAS standard scores of 32.8 ± 8.5 vs. 31.8 ± 9.9, respectively (p = 0.170). Similarly, the mean BAI standard scores were 31.4 ± 8.3 vs. 31.2 ± 9.5, respectively (p = 0.119). Logistic regression analysis showed that the factors of female gender ( β = -1.230, p < 0.001), old age ( β = 0.216, p < 0.001), number of antihypertensive drugs ( β = 1.957, p < 0.001), and cost per tablet ( β = 1.340, p < 0.001) were significantly related to the white coat effect.

Conclusions

Anxiety was not necessary for the white coat effect in hypertension patients during treatment. Female gender, old age, number of antihypertensive drugs used and cost per tablet were related to the white coat effect in hypertension patients during treatment.

Relations between white coat effect of blood pressure and arterial stiffness

The aim of this study was to analyze the relationship between brachial-ankle pulse wave velocity (b-a PWV) and white coat effect (WCE), that is the difference between the elevated office blood pressure (BP) and the lower mean daytime pressure of ambulatory BP, in a mixed population of normotention, untreated sustained hypertension, sustained controlled hypertension, sustained uncontrolled hypertension, white coat hypertension, white coat uncontrolled hypertension. A total of 444 patients with WCE for systolic BP (54.1% female, age 61.86 ± 13.3 years) were enrolled in the study. Patients were separated into low WCE (<9.5 mm Hg) and high WCE (≥9.5 mm Hg) according to the median of WCE. The subjects with a high WCE showed a greater degree of arterial stiffness than those with a low WCE for systolic BP values (P < .05). The b-a PWV were 17.2 ± 3.3 m/s and 18.4 ± 3.4 m/s in low WCE and high WCE, respectively. The b-a PWV increased with the increase of WCE, showing a positive correlation between them (P > .05 for non-linearity). The significant association between the high WCE and the b-a PWV was confirmed by the results of multiple regression analysis after adjusting for confounding factors (β = .78, 95% Cl .25-1.31, P = . 004). Similar results were observed in subgroups. In conclusion, WCE is significantly associated with arterial stiffness. More research is needed to determine the WCE and target organ damage.

Anxiety is associated with higher blood pressure rise induced by cuff inflation

SUBJECTS

To assess whether anxiety is associated with a higher rise of blood pressure induced by cuff inflation.

METHODS

At first, intro-aortic blood pressure was continuously record before cuff inflation as baseline value in 234 patients underwent coronary angiography, then the cuff was inflated to 200 mmHg and the intro-aortic blood pressure was record again as cuff inflation blood pressure. According to anxiety score, the patients were divided into anxiety group, subanxiety group, and nonanxiety group. The difference between the baseline blood pressure and the cuff inflation blood pressure was calculated as cuff inflation-induced blood pressure elevation. When the difference ≥10 mmHg, cuff inflation-induced blood pressure elevation was diagnosed.

RESULTS

The cuff inflation systolic blood pressure (134.9 ± 22.4 versus 131.6 ± 22.3  mmHg, P < 0.01) and diastolic blood pressure (80.5 ± 11.9 versus 78.4 ± 11.6 mmHg, P < 0.01) were significantly higher than the baseline values, thus the mean cuff inflation-induced blood pressure elevation on systolic blood pressure was 3.3 ± 4.7 mmHg and that on diastolic blood pressure was 2.1 ± 4.9 mmHg. The anxiety subgroup had significantly higher percentage increase-systolic blood pressure and percentage increase-diastolic blood pressure levels (4.5 ± 3.1% and 5.6 ± 6.3%) than the nonanxiety subgroup (1.9 ± 3.3% and 2.0 ± 6.5%), meanwhile these values in the subanxiety subgroup were higher (3.2 ± 4.1% and 3.4 ± 5.7%) than the nonanxiety subgroup.

CONCLUSION

Cuff inflation can induce a transient rise of intro-aortic blood pressure. Anxiety is associated with higher cuff inflation-induced blood pressure elevation.

An Update on Refractory Hypertension

Purpose of Review

To update on definition, diagnosis, prevalence, patient characteristics, pathophysiology, and treatment of refractory hypertension (RfHTN).

Recent Findings

Refractory hypertension (RfHTN) is defined as blood pressure (BP) that is uncontrolled despite using ≥ 5 antihypertensive medications of different classes, including a long-acting thiazide diuretic and a mineralocorticoid receptor antagonist (MRA) at maximal or maximally tolerated doses. This new phenotype is different from resistant hypertension (RHTN), defined as BP that is uncontrolled despite using ≥ 3 medications, commonly a long-acting calcium channel blocker (CCB), a blocker of the renin-angiotensin system (angiotensin-converting enzyme [ACE] inhibitor or angiotensin receptor blocker [ARB]), and a diuretic. The RHTN phenotype includes controlled RHTN, BP that is controlled on 4 or more medications. RfHTN is largely attributable to increased sympathetic activity, unlike RHTN, which is mainly due to increased intravascular fluid volume frequently caused by hyperaldosteronism and chronic excessive sodium ingestion. Compared to those with controlled RHTN, patients with RfHTN have a higher prevalence of target organ damage and do not have elevated aldosterone levels. Ongoing clinical trials are assessing the safety and efficacy of using devices to aid with BP control in patients with RfHTN.

Summary

RfHTN is a separate entity from RHTN and is generally attributable to increased sympathetic activity.

Refractory Hypertension: a Narrative Systematic Review with Emphasis on Prognosis

PURPOSE OF REVIEW

To perform a narrative systematic review on refractory hypertension (RfHT) with particular emphasis on prognosis.

RECENT FINDINGS

There were 37 articles on RfHT, 13 non-systematic reviews, and 24 original studies. RfHT, a recently described extreme phenotype of anti-hypertensive treatment failure, shall be defined as uncontrolled out-of-office blood pressure (BP) levels despite the use of at least 5 anti-hypertensive drugs, including a long-acting diuretic and a mineraloreceptor antagonist. Its prevalence ranges from 0.5 to 4.3% of general treated hypertensives and between 3.6 and 51.4% of patients with resistant hypertension (RHT). RfHT is associated with younger age, African ancestry, obesity, hypertension-mediated organ damage and clinical cardiovascular diseases, and with some comorbidities, such as diabetes and obstructive sleep apnea. Its physiopathological mechanisms probably involve sympathetic overactivity and not volume overload. Patients with RfHT have a worse prognosis than non-refractory RHT individuals, with higher risks of adverse cardiovascular and renal outcomes and of mortality. RfHT represents a rare but true extreme phenotype of anti-hypertensive treatment failure distinct from RHT and with a significantly worse prognosis. Identifying such individuals is important to tailor specific interventions.

[Refractory and resistant hypertension in patients with type 2 diabetes mellitus: differences in metabolic profile and endothelial function]

AIM

To determine the prevalence of refractory hypertension (RfH) in patients with and without type 2 diabetes mellitus (DM), as well as to evaluate whether diabetic patients with RfH significant differ from those with uncontrolled resistant hypertension (RH) in clinical phenotype, metabolic profile and endothelial function.

MATERIALS AND METHODS

The study included 193 patients with RH: RH 74 patients with diabetes and 119 patients without DM. Uncontrolled RH and RfH were defined by the presence of uncontrolled blood pressure BP (140 and/or 90 mm Hg) despite the use of 3 but 5 antihypertensive drugs (for RH) and 5 antihypertensive drugs, including a mineralocorticoid receptor antagonist (for RfH). Clinical examination, lab tests were performed. Flow-mediated dilation (FMD) and vasoreactivity of middle cerebral artery (MCA) using both breath-holding and hyperventilation test were measured by high-resolution ultrasound.

RESULTS

The prevalence of refractory hypertension in patients with and without DM was similar (30% vs 28%, respectively). No differences in BP levels, data of echocardiography and clinical phenotype were found between the diabetic groups, but value of HOMA index, plasma resistin level and postprandial glycaemia were higher in patients with RfH. FMD and MCA reactivity to the breath-holding test were worse in patients with RfH, and they had a more pronounced vasoconstrictor response of MCA to the hyperventilation test compared to patients with RH.

CONCLUSION

The prevalence of RfH is the same in patients with and without diabetes. Diabetic patients with refractory hypertension have a more unfavorable metabolic profile and greater impairment of endothelial function than patients with uncontrolled resistant hypertension.

Prevalence and clinical profile of refractory hypertension in a large cohort of patients with resistant hypertension

Refractory hypertension (RfHT) is an extreme phenotype of resistant hypertension (RHT) and is considered uncontrolled blood pressure (BP) despite the use of five or more antihypertensives. The objective of this study was to characterize the prevalence and clinical profile of RfHT patients in a historical cohort of patients with RHT at two different times: before and after the introduction of spironolactone. First, this cross-sectional study evaluated 1048 RHT patients (72.3% females, mean [SD] age: 61.2 [11.3] years) referred to a hypertension clinic (prespironolactone period). All patients were submitted to a standard protocol including clinical and complementary exams. Second, the analysis evaluated patients after the introduction of spironolactone (postspironolactone period). Statistical analysis included bivariate comparisons between patients with RHT and patients with RfHT and logistic regressions to assess the independent correlations of RfHT. A total of 146 patients (13.9%) remained refractory despite the use of at least five antihypertensives (prespironolactone period). After the introduction of spironolactone, the prevalence increased to 17.6%. For any criterion, RfHT patients were younger and more obese. In the initial period, current smoking and left ventricular hypertrophy were independently correlated with RfHT. Furthermore, after spironolactone use, RfHT patients had lower aortic stiffness and peripheral artery disease (PAD), pointing to a lower cardiovascular risk despite the lack of BP control. Younger age and lower prevalence of PAD correlated independently with RfHT. In conclusion, there was a high prevalence of RfHT, especially in younger and obese patients, and spironolactone use seemed to reduce cardiovascular risk despite the lack of BP control.

Refractory Hypertension and Risks of Adverse Cardiovascular Events and Mortality in Patients With Resistant Hypertension: A Prospective Cohort Study

Background The long-term prognosis of refractory hypertension (RfHT), defined as failure to control blood pressure (BP) levels despite an antihypertensive treatment with ≥5 medications including a diuretic and mineraloreceptor antagonist, has never been evaluated. Methods and Results In a prospective cohort study with 1576 patients with resistant hypertension, patients were classified as refractory or nonrefractory based on uncontrolled clinic (or office) and ambulatory BPs during the first 2 years of follow-up. Multivariate Cox analyses examined the associations between the diagnosis of RfHT and the occurrence of total cardiovascular events (CVEs), major adverse CVEs, and cardiovascular and all-cause mortality, after adjustments for other risk factors. In total, 135 patients (8.6%) had RfHT by uncontrolled ambulatory BPs and 167 (10.6%) by uncontrolled clinic BPs. Over a median Follow-Up of 8.9 years, 338 total CVEs occurred (288 major adverse CVEs, including 124 myocardial infarctions, and 96 strokes), and 331 patients died, 196 from cardiovascular causes. The diagnosis of RfHT, using either classification by clinic or ambulatory BPs, was associated with significantly higher risks of major adverse CVEs, cardiovascular mortality, and stroke incidence, with hazard ratios varying from 1.54 to 2.14 in relation to patients with resistant nonrefractory hypertension; however, the classification based on ambulatory BPs was better in identifying higher risk patients than the classification based on clinic BP levels. Conclusions Patients with RfHT, particularly when defined by uncontrolled ambulatory BP levels, had higher risks of major adverse CVEs and mortality in relation to patients with resistant but nonrefractory hypertension, supporting the concept of refractory hypertension as a true extreme phenotype of antihypertensive treatment failure.

Reserpine Substantially Lowers Blood Pressure in Patients With Refractory Hypertension: A Proof-of-Concept Study

BACKGROUND

Refractory hypertension (RfHTN), a phenotype of antihypertensive treatment failure, is defined as uncontrolled automated office blood pressure (AOBP) ≥130/80 mm Hg and awake ambulatory blood pressure (ABP) ≥130/80 mm Hg on ≥5 antihypertensive medications, including chlorthalidone and a mineralocorticoid receptor antagonist. Previous studies suggest that RfHTN is attributable to heightened sympathetic tone. The current study tested whether reserpine, a potent sympatholytic agent, lowers blood pressure (BP) in patients with RfHTN.

METHODS

Twenty-one out of 45 consecutive patients with suspected RfHTN were determined to be fully adherent with their antihypertensive regimen. Seven patients agreed to participate in the current clinical trial with reserpine and 6 patients completed the study. Other sympatholytic medications, such as clonidine or guanfacine, were tapered and discontinued before starting reserpine. Reserpine 0.1 mg daily was administered in an open-label fashion for 4 weeks. All patients were evaluated by AOBP and 24-hour ABP at baseline and after 4 weeks of treatment.

RESULTS

Reserpine lowered mean systolic and diastolic AOBP by 29.3 ± 22.2 and 22.0 ± 15.8 mm Hg, respectively. Mean 24-hour systolic and diastolic ABPs were reduced by 21.8 ± 13.4 and 15.3 ± 9.6 mm Hg, mean awake systolic and diastolic ABPs by 23.8 ± 11.8 and 17.8 ± 9.2 mm Hg, and mean asleep systolic and diastolic ABPs by 21.5 ± 11.4 and 13.7 ± 6.4 mm Hg, respectively.

CONCLUSIONS

Reserpine, a potent sympatholytic agent, lowers BP in patients whose BP remained uncontrolled on maximal antihypertensive therapy, lending support to the hypothesis that excess sympathetic output contributes importantly to the development of RfHTN.

Antihypertensive Medication Adherence and Confirmation of True Refractory Hypertension

Refractory hypertension (RfHTN) is a phenotype of antihypertensive treatment failure defined as uncontrolled BP despite the use of effective doses of ≥5 antihypertensive medications including a long-acting thiazide-like diuretic (chlorthalidone) and a mineralocorticoid receptor antagonist. The degree of medication nonadherence is unknown among patients with RfHTN. In this prospective evaluation, 54 patients with apparent RfHTN were recruited from the University of Alabama at Birmingham Hypertension Clinic after having uncontrolled BP at 3 or more clinic visits. All patients' BP was evaluated by automated office BP and 24-hour ambulatory BP monitoring (n=49). Antihypertensive medication adherence was determined by measuring 24-hour urine specimens for antihypertensive medications and their metabolites by high-performance liquid chromatography-tandem mass spectrometry (n=45). Of the 45 patients who completed 24-hour ambulatory BP monitoring, 40 (88.9%) had confirmed RfHTN based on an elevated automated office BP (≥130/80 mm Hg), mean 24-hour ABP (≥125/75 mm Hg), and mean awake (day-time) ABP (≥130/80 mm Hg). Out of the 40 fully evaluated patients with RfHTN, 16 (40.0%) were fully adherent with all prescribed medications. Eighteen (45.0%) patients were partially adherent and 6 (15.0%) had none of the prescribed agents detected in their urine. Of 18 patients who were partially adherent, 5 (12.5%) were adherent with at least 5 medications, including chlorthalidone and the mineralocorticoid receptor antagonist, consistent with true RfHTN. Of patients identified as having apparent RfHTN, 52.5% were adherent with at least 5 antihypertensive medications, including chlorthalidone and a mineralocorticoid receptor antagonist, confirming true RfTHN. These findings validate RfHTN as a rare, but true phenotype of antihypertensive treatment failure.

Clinic Versus Ambulatory Blood Pressure in Resistant Hypertension: Impact of Antihypertensive Medication Nonadherence

Clinic-ambulatory blood pressure (BP) difference is influenced by patients- and device-related factors and inadequate clinic-BP measurement. We investigated whether nonadherence to antihypertensive medications may also influence this difference in a post hoc analysis of the DENERHTN trial (Renal Denervation for Hypertension). We pooled the data of 77 out of 106 evaluable patients with apparent resistant hypertension who received a standardized antihypertensive treatment and had both ambulatory BP and drug-screening results available at baseline after 1 month of standardized triple therapy and at 6 months on a median of 5 antihypertensive drugs. After drug assay samplings on study visits, patients took their antihypertensive treatment under supervision immediately after the start of the ambulatory BP recording, and supine clinic BP was measured 24 hours post-dosing; both allowed to calculate the clinic minus daytime ambulatory systolic BP (SBP) difference (clinic-SBP–day-SBP). A total of 29 (37.7%) were found nonadherent to medications at baseline and 38 (49.4%) at 6 months. At baseline, the mean clinic-SBP–day-SBP difference in the nonadherent group was 12.7 mm Hg (95% CI, 7.8–17.7 mm Hg, P <0.001). In contrast, clinic SBP was almost identical to day-SBP in the adherent group (clinic-SBP–day-SBP difference, 0.1 mm Hg; 95% CI, −3.3 to 3.5 mm Hg; P =0.947). Similar observations were made at 6 months. Using receiver operating characteristics curves, we found that a 6 mm Hg cutoff of clinic-SBP–day-SBP difference had 67% sensitivity and 69% specificity to predict nonadherence to the triple therapy at baseline. In conclusion, a large clinic-SBP–day-SBP difference may help discriminating between adherence and nonadherence to treatment in patients with resistant hypertension.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01570777.

Unattended versus attended automated office blood pressure: Systematic review and meta-analysis of studies using the same methodology for both methods

There is increasing interest in unattended automated office blood pressure (OBP) measurement, which gives lower blood pressure values than the conventional auscultatory OBP. Whether unattended automated OBP differs from standardized attended automated OBP performed using the same device and measurement protocol remains uncertain. A systematic review and meta-analysis of studies (aggregate data) comparing unattended vs attended automated OBP using the same device and measurement protocol (conditions, number of measurements, visits) was performed. Ten eligible studies (n = 1004, weighted age 60.8 ± 4.2 [SD] years, 55% males) were analyzed. Unattended OBP (pooled systolic/diastolic 133.9 [95% CI: 129.7, 138]/80.6 [95% CI: 77, 84.2] mm Hg) did not differ from attended OBP (135.3 [95% CI: 130.9, 139.6]/81 [95% CI: 77.6, 84.3] mm Hg); pooled systolic OBP difference -1.3, 95% CI: -4.3, 1.7 mm Hg and diastolic -0.4, 95% CI: -1.2, 0.3 mm Hg. Nine of ten studies achieved high quality score and no publication bias was identified. Meta-regression analysis did not reveal any effect of age, gender, or attended systolic OBP on the unattended-attended systolic OBP difference (P = NS for all). However, there was a trend toward higher attended than unattended OBP at higher OBP levels. These data suggest that, when the same device and measurement protocol are used, attended automated OBP provides similar blood pressure values as unattended automated OBP. Although unattended automated OBP is theoretically advantageous as it ensures that standardized conditions and measurement protocol are used, attended automated OBP, if carefully performed, appears to be a reasonable and practical alternative.

Resistant and refractory hypertension: two sides of the same disease?

Refractory hypertension (RfH) is an extreme phenotype of resistant hypertension (RH), being considered an uncontrolled blood pressure besides the use of 5 or more antihypertensive medications, including a long-acting thiazide diuretic and a mineralocorticoid antagonist. RH is common, with 10-20% of the general hypertensives, and its associated with renin angiotensin aldosterone system hyperactivity and excess fluid retention. RfH comprises 5-8% of the RH and seems to be influenced by increased sympathetic activity. RH patients are older and more obese than general hypertensives. It is strongly associated with diabetes, obstructive sleep apnea, and hyperaldosteronism status. RfH is more frequent in women, younger patients and Afro-americans compared to RFs. Both are associated with increased albuminuria, left ventricular hypertrophy, chronic kidney diseases, stroke, and cardiovascular diseases. The magnitude of the white-coat effect seems to be higher among RH patients. Intensification of diuretic therapy is indicated in RH, while in RfH, therapy failure imposes new treatment alternatives such as the use of sympatholytic therapies. In conclusion, both RH and RfH constitute challenges in clinical practice and should be addressed as distinct clinical entities by trained professionals who are capable to identify comorbidities and provide specific, diversified, and individualized treatment.

Refractory Hypertension Is not Attributable to Intravascular Fluid Retention as Determined by Intracardiac Volumes

Refractory hypertension (RfHTN) is an extreme phenotype of antihypertensive treatment failure defined as lack of blood pressure control with ≥5 medications, including a long-acting thiazide and a mineralocorticoid receptor antagonist. RfHTN is a subgroup of resistant hypertension (RHTN), which is defined as blood pressure >135/85 mm Hg with ≥3 antihypertensive medications, including a diuretic. RHTN is generally attributed to persistent intravascular fluid retention. It is unknown whether alternative mechanisms are operative in RfHTN. Our objective was to determine whether RfHTN is characterized by persistent fluid retention, indexed by greater intracardiac volumes determined by cardiac magnetic resonance when compared with controlled RHTN patients. Consecutive patients evaluated in our institution with RfHTN and controlled RHTN were prospectively enrolled. Exclusion criteria included advanced chronic kidney disease and masked or white coat hypertension. All enrolled patients underwent biochemical testing and cardiac magnetic resonance. The RfHTN group (n=24) was younger (mean age, 51.7±8.9 versus 60.6±11.5 years; P=0.003) and had a greater proportion of women (75.0% versus 43%; P=0.02) compared with the controlled RHTN group (n=30). RfHTN patients had a greater left ventricular mass index (88.3±35.0 versus 54.6±12.5 g/m²; P<0.001), posterior wall thickness (10.1±3.1 versus 7.7±1.5 mm; P=0.001), and septal wall thickness (14.5±3.8 versus 10.0±2.2 mm; P<0.001). There was no difference in B-type natriuretic peptide levels and left atrial or ventricular volumes. Diastolic dysfunction was noted in RfHTN. Our findings demonstrate greater left ventricular hypertrophy without chamber enlargement in RfHTN, suggesting that antihypertensive treatment failure is not attributable to intravascular volume retention.

Prevalence and Clinical Characteristics of Refractory Hypertension

Background

We aimed to estimate the prevalence of refractory hypertension (RfH) and to determine the clinical differences between these patients and resistant hypertensives (RH). Secondly, we assessed the prevalence of white‐coat RfH and clinical differences between true‐ and white‐coat RfH patients.

Methods and Results

The present analysis was conducted on the Spanish Ambulatory Blood Pressure Monitoring Registry database containing 70 997 treated hypertensive patients. RH and RfH were defined by the presence of elevated office blood pressure (≥140 and/or 90 mm Hg) in patients treated with at least 3 (RH) and 5 (RfH) antihypertensive drugs. White‐coat RfH was defined by RfH with normal (<130/80 mm Hg) 24‐hour blood pressure. A total of 11.972 (16.9%) patients fulfilled the standard criteria of RH, and 955 (1.4%) were considered as having RfH. Compared with RH patients, those with RfH were younger, more frequently male, and after adjusting for age and sex, had increased prevalence of target organ damage, and previous cardiovascular disease. The prevalence of white coat RfH was lower than white‐coat RH (26.7% versus 37.1%, P<0.001). White‐coat RfH, in comparison with those with true RfH, showed a lower prevalence of both left ventricular hypertrophy (22% versus 29.7%; P=0.018) and microalbuminuria (28.3% versus 42.9%; P=0.047).

Conclusions

The prevalence of RfH was low and these patients had a greater cardiovascular risk profile compared with RH. One out of 4 patients with RfH have normal 24‐hour blood pressure and less target organ damage, thus indicating the important role of ambulatory blood pressure monitoring in guiding antihypertensive therapy in difficult‐to‐treat patients.

Refractory versus resistant hypertension: Novel distinctive phenotypes

Resistant hypertension (RHTN) is relatively common with an estimated prevalence of 10-20% of treated hypertensive patients. It is defined as blood pressure (BP) >140/90 mmHg treated with ≥3 antihypertensive medications, including a diuretic, if tolerated. Refractory hypertension is a novel phenotype of severe antihypertensive treatment failure. The proposed definition for refractory hypertension, i.e. BP >140/90 mmHg with use of ≥5 different antihypertensive medications, including a diuretic and a mineralocorticoid receptor antagonist (MRA) has been applied inconsistently. In comparison to RHTN, refractory hypertension seems to be less prevalent than RHTN. This review focuses on current knowledge about this novel phenotype compared with RHTN including definition, prevalence, mechanisms, characteristics and comorbidities, including cardiovascular risk. In patients with RHTN excess fluid retention is thought to be a common mechanism for the development of RHTN. Recently, evidence has emerged suggesting that refractory hypertension may be more of neurogenic etiology due to increased sympathetic activity as opposed to excess fluid retention. Treatment recommendations for RHTN are generally based on use and intensification of diuretic therapy, especially with the combination of a long-acting thiazide-like diuretic and an MRA. Based on findings from available studies, such an approach does not seem to be a successful strategy to control BP in patients with refractory hypertension and effective sympathetic inhibition in such patients, either with medications and/or device based approaches may be needed.