Masked Hypertension as an Unrecognized Destructive Condition

To the Editor:

We have read the article “Masked Hypertension Defined by Home Blood Pressure Monitoring Is Associated With Impaired Flow‐Mediated Vasodilatation in Patients With Cardiovascular Risk Factors” written by Kabutoya and colleagues1 with great interest. They speculated that home blood pressure (BP) and masked hypertension defined by home BP would be associated with integrated flow‐mediated dilatation (FMD) response in patients with a cardiovascular risk factor. The study concluded that home systolic BP was associated with a decrease in FMD. This finding may likely contribute to an increased incidence of cardiovascular events in this group. The subject is important in terms of daily practice and the study justifies emphasis with its successful design and documentation.

Ambulatory and home BP measurement have been shown to be superior to conventional measurement of BP in terms of reproducibility, relationship to the impact of high BP on target organs, and the prediction of cardiovascular events.2 Masked hypertension is defined as a clinical condition in which a patient's office BP is <140/90 mm Hg and home BP is ≥135 mm Hg and/or 85 mm Hg.3 Reactivity to daily life stressors and behavioral factors such as smoking, alcohol use, contraceptive use in women, and sedentary habits can influence masked hypertension. Masked hypertension should also be investigated in individuals who are at increased risk for cardiovascular complications, including patients with kidney disease.4 Masked hypertension defined by 24‐hour ambulatory BP is associated with an increased serum glucose level and urinary albumin‐creatinine ratio.5 For this reason, if the authors gave information about kidney function tests and lifestyle of patients, the results of the present study may be useful and different.

Patients with masked hypertension have been demonstrated to have a greater‐than‐normal prevalence of organ damage, particularly with higher prevalence of metabolic risk factors, left ventricular mass index, carotid intima‐media thickness, and impaired large artery distensibility compared with patients with a truly normal BP level. Masked hypertension is a predictor of cardiovascular disease, and FMD may measure the endothelial dysfunction and accelerated atherogenesis associated with masked hypertension. FMD measurement is a gold standard method for endothelial function; however, it may be associated with many conditions that are related to inflammation or endothelial impairment. Therefore, researchers who use this method should pay attention to inflammatory diseases or related conditions. Obstructive sleep apnea syndrome (OSAS) and nonalcoholic fatty liver disease (NAFLD) are common in clinical practice. Cardiovascular complications, which are also common in patients with OSAS, have been linked to morbidity and mortality in these patients based on endothelial dysfunction. In addition, the presence and degree of NAFLD are associated with higher inflammatory parameters. Additionally, common pathways involved in the pathogenesis of NAFLD include hepatic insulin resistance, subclinical inflammation, and atherosclerosis.6 Because NAFLD and OSAS are associated with inflammatory status and insulin resistance, if the authors had mentioned these factors, it would be stronger. Inflammatory status can also be affected by many conditions including inflammatory disease such as psoriasis,7 cardiac syndrome X, and infection.8 In the present study, the authors did not mention some of these possible contributing factors. It would have been better if the authors gave information about these factors.

In conclusion, FMD itself without other inflammatory indicators may not provide information to clinicians about masked hypertension. For this reason, we think that it should be evaluated together with other serum inflammatory markers in routine clinical practice.9 We believe that these findings will act as a guide for further studies that will assess inflammatory status as a surrogate marker of endothelial dysfunction and its relationship with masked hypertension.

Conflict of interests

There are no conflict of interests.