Orthostatic hypertension: recognizing an underappreciated clinical condition

Transient Orthostatic Hypertension During Head-Up Tilt Test in Young Adults: A Phenotype of Blood Pressure Variability

PURPOSE

The mechanisms underlying orthostatic hypertension (OHT) remain poorly understood. The authors evaluated the cardiovascular, cerebrovascular dynamics, and autonomic response to head-up tilt test (HUTT) in young adults with symptoms of orthostatic intolerance and transient OHT.

METHODS

Forty-four female subjects were included (34 ± 13 years old) and categorized in three groups after a 30-minute 70° passive HUTT: symptomatic patients with OHT (surge of systolic blood pressure ≥20 mm Hg for at least 5 minutes at any given time during HUTT), orthostatic intolerance (symptomatic patients without orthostatic blood pressure changes), and healthy asymptomatic control subjects.

RESULTS

At baseline, OHT patients had lower systolic blood pressure than orthostatic intolerance patients (103 ± 8 vs. 116 ± 10 mm Hg, p < 0.01) and lower baroreflex sensitivity than control subjects (15.8 ± 8.3 vs. 27.1 ± 11.7 ms/mm Hg, p = 0.01). On tilt, cardiac output decreased in OHT patients from 6.1 ± 1.4 L/minute during baseline to 5.2 ± 0.8 L/minute after 10 minutes of HUTT (p = 0.01). In OHT patients at 30 minutes of HUTT, sympathetic efferent heart activity was higher (77.4 ± 14.9 normalized units or nu) than orthostatic intolerant patients (63.5 ± 11.8 nu, p = 0.02) and control subjects (65.8 ± 11.2 nu, p = 0.05). Cerebrovascular resistance in OHT was higher than control subjects after 30 minutes (2.2 ± 0.8 vs. 1.6 ± 0.3 cm/second, respectively, p = 0.02).

CONCLUSIONS

This study demonstrates that transient OHT can occur at any given time during HUTT. These patients exhibit a decrease in cardiac output and a hyperadrenergic response to tilt.

Too much of a good thing: a case report of traumatic drop attacks and syncope due to orthostatic hypertension

Background

Orthostatic hypertension (OHT) is the clinical opposite to orthostatic hypotension and is an under-recognized and poorly understood clinical phenomenon. Patients may experience disabling symptoms such as dizziness, chest pain, and shortness of breath. In addition, OHT is associated with important clinical outcomes such as silent cerebral infarcts and cognitive decline.

Case summary

We present the case of a 67-year-old female who experienced frequent drop attacks with and without transient loss of consciousness causing various injuries. A range of standard diagnostic procedures did not yield an explanation for her symptoms but head-up tilt (HUT) testing showed OHT and induced most of her symptoms. Upon initiation of doxazosin, an alpha-blocking drug, she was free of symptoms and blood pressure response was normal on the repeat HUT test.

Discussion

To our knowledge, this is the first report of syncope due to OHT. Orthostatic hypertension is a heterogeneous condition and may occur in young, otherwise healthy individuals but also in older patients with cardiovascular comorbidities. It is thought that symptoms occur because of excessive venous pooling (causing a drop in cardiac output) or adrenergic hypersensitivity (resulting in cerebral vasoconstriction or acute rise in cardiac afterload). Since our patient had a marked response to an alpha-blocking agent, we think baroreflex hypersensitivity is the most likely cause of her complaints. Though syncope is probably rare, OHT should be regarded as a possible explanation of orthostatic symptoms.

Orthostatic hypertension: From pathophysiology to clinical applications and therapeutic considerations

Orthostatic hypertension (OHT), that is, sustained increase in blood pressure after standing, is an increasingly recognized cardiovascular disorder having been examined in much fewer studies compared with orthostatic hypotension (OH). However, in both OHT and OH, dysfunction of the autonomous nervous system is considered to be the primary pathophysiological disturbance, while significant associations with essential hypertension have been observed. Although in many studies OHT has been related to subclinical or clinical target organ damage, there is also evidence denying such an association. Because OHT is defined variably across different studies, the comparison of relevant outcomes is at least problematic. Since evidence about OHT treatment is exclusively based on limited non-randomized studies, no specific recommendations have been developed. Therefore, both the prognostic role and the clinical significance of OHT remain largely undefined. The aim of the present review is to summarize the available evidence regarding the definition, diagnosis, pathophysiology, prognostic role and treatment of OHT and highlight potential clinical implications of this underestimated condition.

Labile hypertension: a new disease or a variability phenomenon?

Blood pressure (BP) is a physiological parameter with short- and long-term variability caused by complex interactions between intrinsic cardiovascular (CV) mechanisms and extrinsic environmental and behavioral factors. Available evidence suggests that not only mean BP values are important, but also BP variability (BPV) might contribute to CV events. Labile hypertension (HTN) is referred to sudden rises in BP and it seems to be linked with unfavorable outcomes. The aim of this article was to review and summarize recent evidence on BPV phenomenon, unraveling the labile HTN concept along with the prognostic value of these conditions.

Diastolic orthostatic hypertension and cardiovascular prognosis in type 2 diabetes: a prospective cohort study

BACKGROUND

In patients with type 2 diabetes, the prognostic impact of an orthostatic rise in blood pressure is not known. Therefore, the aim of this study was to determine the prognostic implications of the diastolic orthostatic blood pressure response in a cohort of patients with type 2 diabetes. We also evaluated associations between different orthostatic blood pressure responses and markers of subclinical cardiovascular organ damage.

METHODS

Office blood pressures were measured in the sitting and in the standing position in 749 patients with type 2 diabetes who participated in the CARDIPP study (Cardiovascular Risk factors in Patients with Diabetes-a Prospective study in Primary care). Diastolic orthostatic hypertension was defined as a rise of diastolic blood pressure ≥10 mmHg and diastolic orthostatic hypotension was defined as a drop of diastolic blood pressure ≥10 mmHg. Recruitment took place between the years 2005-2008, and patients were followed until any of the primary outcome events (cardiovascular death or hospitalization for either myocardial infarction or stroke) occurred or until December 31st, 2014. Measurements of aortic pulse wave velocity and of carotid intima-media thickness were performed at base-line.

RESULTS

Diastolic orthostatic hypertension was found in 140 patients (18.7 %) and was associated with significantly lower risk of cardiovascular events (crude hazard ratio compared with patients with normal systolic and diastolic orthostatic blood pressure response: 0.450, 95 % C.I. 0.206-0.987, P = 0.046). Diastolic orthostatic hypotension was found in 31 patients (4.1 %) and was associated with higher values for aortic pulse wave velocity and carotid intima-media thickness, compared with patients with normal systolic and diastolic orthostatic blood pressure response.

CONCLUSIONS

Diastolic orthostatic hypertension is common in patients with type 2 diabetes, and may be a novel marker for decreased cardiovascular risk in these patients.