Subtypes of masked hypertension and target organ damage in untreated outpatients

Vascular phenotypes in early hypertension

The study characterises vascular phenotypes of hypertensive patients utilising machine learning approaches. Newly diagnosed and treatment-naïve primary hypertensive patients without co-morbidities (aged 18-55, n = 73), and matched normotensive controls (n = 79) were recruited (NCT04015635). Blood pressure (BP) and BP variability were determined using 24 h ambulatory monitoring. Vascular phenotyping included SphygmoCor® measurement of pulse wave velocity (PWV), pulse wave analysis-derived augmentation index (PWA-AIx), and central BP; EndoPAT™-2000® provided reactive hyperaemia index (LnRHI) and augmentation index adjusted to heart rate of 75bpm. Ultrasound was used to analyse flow mediated dilatation and carotid intima-media thickness (CIMT). In addition to standard statistical methods to compare normotensive and hypertensive groups, machine learning techniques including biclustering explored hypertensive phenotypic subgroups. We report that arterial stiffness (PWV, PWA-AIx, EndoPAT-2000-derived AI@75) and central pressures were greater in incident hypertension than normotension. Endothelial function, percent nocturnal dip, and CIMT did not differ between groups. The vascular phenotype of white-coat hypertension imitated sustained hypertension with elevated arterial stiffness and central pressure; masked hypertension demonstrating values similar to normotension. Machine learning revealed three distinct hypertension clusters, representing 'arterially stiffened', 'vaso-protected', and 'non-dipper' patients. Key clustering features were nocturnal- and central-BP, percent dipping, and arterial stiffness measures. We conclude that untreated patients with primary hypertension demonstrate early arterial stiffening rather than endothelial dysfunction or CIMT alterations. Phenotypic heterogeneity in nocturnal and central BP, percent dipping, and arterial stiffness observed early in the course of disease may have implications for risk stratification.

Isolated nocturnal hypertension in relation to host and environmental factors and clock genes

Isolated nocturnal hypertension (INH) is a special type of out-of-office hypertension. Its determinants and pathophysiology remain unclear. In a nested case-control study, we intend to investigate the host, environmental, and genetic factors in relation to INH. Among 2030 outpatients screened from December 2008 till June 2015, 128 patients with INH were identified, and then 128 normotensives were matched according to sex and age. INH was an elevated nocturnal blood pressure (BP ≥120/70 mmHg) in the presence of a normal daytime BP (< 135/85 mmHg). Host factors included age, sex, body mass index, smoking and drinking, sleep time and duration, heart rate, serum lipids, and serum creatinine. Environmental cues encompassed season, ambient temperature, atmospheric pressure, humidity, and wind speed, and genetic cues 29 single-nucleotide polymorphisms (SNPs) in 12 clock genes. Daytime and nighttime BPs averaged 124.9/80.7  and 114.5/73.7 mmHg, respectively, in the INH patients and 121.0/76.5 and 101.8/63.3 mmHg in the normotensive controls. Stepwise logistic regression analyses revealed that INH was associated with nighttime heart rate (P = .0018), sleep duration (P = .0499), and relative humidity (P = .0747). The odds ratios (95% CI) for each 10 beats/min faster nighttime heart rate and 10% lower relative humidity were 1.82 (1.25-2.65) and 0.82 (0.67-1.00), respectively. Irrespective of the genetic models, no significant association was observed between INH and the SNPs (P ≥ .054). In conclusion, INH was associated with host and environmental factors rather than genetic markers.

Association of Nighttime Masked Uncontrolled Hypertension With Left Ventricular Hypertrophy and Kidney Function Among Patients with Chronic Kidney Disease Not Receiving Dialysis

IMPORTANCE

Nighttime hypertension is prevalent and associated with adverse outcomes in patients with chronic kidney disease (CKD), but nighttime hypertension, a subtype of masked uncontrolled hypertension (MUCH), is often undetected among patients with controlled office blood pressure. Little attention has been paid to patients with CKD and nighttime MUCH.

OBJECTIVE

To investigate the prevalence of nighttime MUCH and its associations with cardiovascular and kidney outcomes in patients with CKD who were not receiving dialysis.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included patients with nondialysis CKD and hypertension, enrolled in Shanghai, China, from July 2012 through November 2020 and followed up for a median of 39 months.

EXPOSURES

Participants were classified as having controlled hypertension, sustained hypertension, and MUCH, which was further divided into isolated nighttime MUCH and day-night MUCH, assessed by office and ambulatory blood pressure monitoring.

MAIN OUTCOMES AND MEASURES

Left ventricular hypertrophy (LVH) was determined by echocardiography. The composite kidney outcome consisted of end-stage kidney diseases (ESKD) and a reduction of estimated glomerular filtration rate (eGFR) by 50% or more. Logistic and Cox regression assessed the associations of hypertension subtypes with LVH and kidney outcomes.

RESULTS

The 675 patients (425 [63.0%] men; mean [SD] age, 50.8 [15.9] years; mean [SD] eGFR, 61.6 [29.4] mL/min/1.73 m2) included 125 (19.3%) with controlled hypertension, 244 (37.6%) with MUCH, and 280 (43.1%) sustained hypertension. Among patients with MUCH, 2 (0.8%) had isolated daytime MUCH, 154 (63.1%) had isolated nighttime MUCH, and 88 (36.1%) had day-night MUCH. During a median (IQR) follow-up of 39 (19-64) months, 130 composite kidney events, including 97 ESKD events, occurred. Compared with controlled hypertension, MUCH and sustained hypertension were associated with LVH (eg, MUCH: odds ratio [OR], 2.94; 95% CI, 1.18-7.34; P = .02) and the composite kidney outcome (eg, MUCH: hazard ratio [HR], 4.12; 95% CI, 1.75-9.73; P = .001) after adjustment for age, sex, proteinuria, eGFR, and other baseline risk factors. Multivariate-adjusted associations were also significant between day-night MUCH and LVH (OR, 3.26; 95% CI, 1.15-9.25) and between isolated nighttime MUCH and the composite kidney outcome (HR, 4.27; 95% CI, 1.69-10.77).

CONCLUSIONS AND RELEVANCE

In this cohort study, nighttime MUCH was common and associated with LVH and poor kidney outcomes among patients with hypertension and nondialysis CKD. These findings suggest that ambulatory blood pressure monitoring was inadequately used in patients with CKD and hypertension, calling for more widespread use, even in patients with controlled office hypertension.

Ambulatory blood pressure monitoring for the management of hypertension

ABSTRACT

Ambulatory blood pressure monitoring (ABPM) has become indispensable in the current management of hypertension. ABPM is particularly useful in the accurate diagnosis of hypertension. Its diagnostic thresholds had been recently established based on hard clinical outcomes. Cross-classification of patients according to office and ambulatory blood pressure identifies white-coat, masked, and sustained hypertension. ABPM is also useful in cardiovascular (CV) risk assessment. It provides information on daytime and nighttime blood pressure and circadian rhythm, particularly nighttime blood pressure dipping. Nighttime blood pressure is predictive of CV risk independent of office and daytime blood pressure. Isolated nocturnal hypertension is a special form of masked hypertension, with normal daytime but elevated nocturnal blood pressure. It also helps in the evaluation of blood pressure fluctuation and variation, such as morning blood pressure surge and reading-to-reading blood pressure variability. ABPM may derive several other indexes, such as ambulatory blood pressure index and salt sensitivity index, which may be useful in CV evaluations.

Aortic arch calcification: a novel parameter for prediction of masked hypertension

BACKGROUND

Masked hypertension is directly related to increased cardiovascular morbidity and mortality but remains underdiagnosed in clinical practice. The aim of the study was to search the role of aortic arch calcification (AAC) in the diagnosis of masked hypertension.

METHODS AND RESULTS

Among the patients who underwent ambulatory blood pressure monitoring (ABPM) in our clinic, those with office blood pressure (OBP) <140/90 mmHg were included in the study population. According to OBP, they were divided into two groups as normal (<130/85 mmHg) and high normal (130-139/85-89 mmHg) OBP groups. Subjects were also investigated for the presence of masked hypertension with ABPM and searched in masked hypertension and control groups. Masked hypertension was defined as in the latest 2017 ACC/AHA Hypertension guideline and was diagnosed as the daytime BP ≥ 135/85 mmHg and nighttime BP ≥ 120/70 mmHg. AAC was evaluated on direct X-ray telecardiography. Diagnosis of masked hypertension was searched depending on the presence of AAC and OBP measurements as well. A total of 216 volunteers were involved in the study [mean age 45.2 ± 12.2 years; female gender 120 (55.5%)]. One hundred ten volunteers (50.9%) had masked hypertension according to the ABPM. AAC was significantly more common in the masked hypertension group (44.5% vs. 26.4%) (P = 0.005). AAC had a positive predictive value of 79% in those with high normal OBP in the diagnosis of masked hypertension, and also AAC had a negative predictive value of 74% in those with normal OBP.

CONCLUSION

AAC can be used as a reliable diagnostic tool to exclude and predict masked hypertension during office examination.

Which is responsible for target organ damage in masked hypertension? Is it an increase in blood pressure or a disruption of the circadian rhythm?

OBJECTIVE

Masked hypertension (MH) and non-dipping pattern are conditions associated with target organ damage and cardiovascular risk, which are frequently observed together. We aimed to show the relationship between the target organ damage observed in MH and the deterioration in the dipping pattern.

METHODS

Patients who underwent ambulatory blood pressure monitoring (ABPM) and office blood pressure (BP) <140/90 mmHg were retrospectively screened. In ABPM data, those with daytime BP ≥135/85 mmHg and night BP ≥120/70 mmHg were included in the MH group, while the others were included in the normotensive group. The patients were grouped as dipper, non-dipper and reverse-dipper according to ABPM results. Left ventricular mass index (LVMI), glomerular filtration rate (GFR) and serum creatinine levels were used to determine target organ damage.

RESULTS

289 patients [mean age 46.6 ± 12.4 years, 136 (47.1%) males], 154 (53.3%) of whom had MH were included in our study. GFR value was found to be significantly lower, serum creatinine levels and LVMI were significantly higher in patients with MH compared to normotensives (p < .05, for all). When the subgroups were examined, it was found that this difference was associated with the disruption in the dipping pattern. In patients with MH, dipping pattern disruption without change in systolic BP was independently associated with an increase in LVMI (p < .05, for both).

CONCLUSION

Target organ damage seen in MH may be due to the deterioration of the dipping pattern.