Twenty-four-hour blood pressure profile, orthostatic hypotension, and cardiac dysautonomia in elderly type 2 diabetic hypertensive patients

Orthostatic Hypotension in Adults With Hypertension: A Scientific Statement From the American Heart Association

Although orthostatic hypotension (OH) has long been recognized as a manifestation of autonomic dysfunction, a growing body of literature has identified OH as a common comorbidity of hypertension. This connection is complex, related to pathophysiology in blood pressure regulation and the manner by which OH is derived as the difference between 2 blood pressure measurements. While traditional therapeutic approaches to OH among patients with neurodegenerative disorders focus on increasing upright blood pressure to prevent cerebral hypoperfusion, the management of OH among patients with hypertension is more nuanced; resting hypertension is itself associated with adverse outcomes among these patients. Although there is substantial evidence that intensive blood pressure treatment does not cause OH in the majority of patients with essential hypertension, some classes of antihypertensive agents may unmask OH in patients with an underlying autonomic impairment. Practical steps to manage OH among adults with hypertension start with (1) a thorough characterization of its patterns, triggers, and cause; (2) review and removal of aggravating factors (often pharmacological agents not related to hypertension treatment); (3) optimization of an antihypertensive regimen; and (4) adoption of a tailored treatment strategy that avoids exacerbating hypertension. These strategies include countermaneuvers and short-acting vasoactive agents (midodrine, droxidopa). Ultimately, further research is needed on the epidemiology of OH, the impact of hypertension treatment on OH, approaches to the screening and diagnosis of OH, and OH treatment among adults with hypertension to improve the care of these patients and their complex blood pressure pathophysiology.

"Arterial stiffness is not associated with changes in the circadian pattern of blood pressure in patients with type 1 diabetes mellitus and cardiovascular autonomic dysfunction"

INTRODUCTION

Cardiovascular autonomic neuropathy (CAN) associates an abnormal circadian pattern in blood pressure (BP) regulation that might be aggravated by the coexistence of arterial stiffness. We aimed to evaluate the effect of arterial stiffness in the circadian rhythm of BP in patients with type 1 diabetes and CAN.

METHODS

Cross-sectional study including 56 consecutive patients with type 1 diabetes and CAN, with (n = 28) or without (n = 24) arterial stiffness as defined by an ankle-brachial index above 1.2. CAN was diagnosed by BP and heart rate responses to active standing and cardiovascular autonomic reflex tests. Absence of nocturnal decrease in BP-"non-dipping" pattern- was defined by a daytime to nighttime decrease in mean BP smaller than 10%.

RESULTS

The study's subjects mean age was 40 ± 11 years-old, their mean duration of diabetes was 22 ± 10 years, and their mean A_1c was 7.9 ± 1.5%. A "non-dipping" pattern was observed in 28 patients (54%) regardless of the presence or absence of arterial stiffness. Age, waist circumference, body mass index, and A_1c, were introduced as independent variables into a multiple regression analysis. The stepwise model (R²: 0.113, p = 0.016) retained only A_1c levels (β: ‒ 0.333, 95% confidence interval [CI]: -3.10 to -0.33) as significant predictor of the percentage of nighttime decrease in mean BP.

CONCLUSIONS

A non-dipping pattern in BP is very common in patients with type 1 diabetes presenting with subclinical CAN and is associated with a poorer metabolic control. On the contrary, coexistence of arterial stiffness is not associated with abnormalities in circadian BP regulation.

Preferential impairment of parasympathetic autonomic function in type 2 diabetes

OBJECTIVE

Cardiovascular autonomic neuropathy is a known complication in type 2 diabetes (T2D). However, the extent of sympathetic dysfunction and its relation to blood pressure (BP) dysregulation is insufficiently studied. We therefore assessed the cardiovascular sympathetic function using a standardized autonomic test-battery.

RESEARCH DESIGN AND METHODS

Forty T2D patients (mean age and duration of diabetes ±SD, 65.5 ± 7.3 and 9.5 ± 4.2 years) and 40 age- and gender-matched controls were examined through autonomic testing, assessing cardiovascular responses to deep breathing, Valsalva maneuver and tilt-table testing. Additionally, 24-hour oscillometric BP and self-reported autonomic symptoms on COMPASS-31 questionnaire was recorded.

RESULTS

Patients with T2D had reduced parasympathetic activity with reduced deep breathing inspiratory:expiratory-ratio (median [IQR] T2D 1.11 [1.08-1.18] vs. controls 1.18 [1.11-1.25] (p = 0.01)), and reduced heart rate variability (p < 0.05). We found no differences in cardiovascular sympathetic function measured through BP responses during the Valsalva maneuver (p > 0.05). 24-hour-BP detected reduced night-time systolic BP drop in T2D (9.8 % ± 8.8 vs. controls 15.8 % ± 7.7 (p < 0.01)) with more patients having reverse dipping. Patients with T2D reported more symptoms of orthostatic intolerance on the COMPASS-31 (p = 0.04).

CONCLUSIONS

Patients with T2D showed reduced parasympathetic activity but preserved short-term cardiovascular sympathetic function, compared to controls, indicating autonomic dysfunction with predominantly parasympathetic impairment. Despite this, T2D patients reported more symptoms of orthostatic intolerance in COMPASS-31 and had reduced nocturnal BP dipping, indicating that these are not a consequence of cardiovascular sympathetic dysfunction.

The Association of Orthostatic Hypotension With Ambulatory Blood Pressure Phenotypes in SPRINT

BACKGROUND

Clinic blood pressure (BP) when measured in the seated position, can miss meaningful BP phenotypes, including low ambulatory BP (white coat effects [WCE]) or high supine BP (nocturnal non-dipping). Orthostatic hypotension (OH) measured using both seated (or supine) and standing BP, could identify phenotypes poorly captured by seated clinic BP alone.

METHODS

We examined the association of OH with WCE and night-to-daytime systolic BP (SBP) in a subpopulation of SPRINT, a randomized trial testing the effects of intensive or standard (<120 vs. <140 mm Hg) SBP treatment strategies in adults at increased risk of cardiovascular disease. OH was assessed during follow-up (6, 12, and 24 months) and defined as a decrease in mean seated SBP ≥20 or diastolic BP ≥10 mm Hg after 1 min of standing. WCE, based on 24-hour ambulatory BP monitoring performed at 27 months, was defined as the difference between 27-month seated clinic and daytime ambulatory BP ≥20/≥10 mm Hg. Reverse dipping was defined as a ratio of night-to-daytime SBP >1.

RESULTS

Of 897 adults (mean age 71.5±9.5 years, 29% female, 28% black), 128 had OH at least once. Among those with OH, 15% had WCE (vs. 7% without OH). Moreover, 25% of those with OH demonstrated a non-dipping pattern (vs. 14% without OH). OH was positively associated with both WCE (OR=2.24; 95%CI: 1.28, 4.27) and reverse dipping (OR=2.29; 95% CI: 1.31, 3.99).

CONCLUSIONS

The identification of OH in clinic was associated with two BP phenotypes often missed with traditional seated BP assessments. Further studies on mechanisms of these relationships are needed.

CLINICAL TRIALS REGISTRATION

Trial Number NCT03569020.

Blood Pressure Variability and Autonomic Dysfunction

PURPOSE OF REVIEW

This review considers the relationship between abnormal blood pressure (BP) variability and autonomic dysfunction through an attempt to answer questions about its clinical relevance and pertinence to diabetes and cardiovascular autonomic neuropathy (CAN) and which therapeutic measures can lessen its cardiovascular impact.

RECENT FINDINGS

Office, ambulatory, and home BP monitoring identify posture-related, circadian, short-term, and long-term BP variabilities. Abnormal BP variability is a risk marker for organ damage, mortality, and cardiovascular events. Moreover, BP variability changes are common in diabetes and associated with CAN and possibly exacerbated by comorbidities like nephropathy, obstructive sleep apnoea syndrome, and chronic pain. The prognostic role of nondipping and reverse dipping is well documented in diabetes. Some findings suggest the possibility of restoring dipping with the dosage time of antihypertensive agents. Diabetes is a favorable scenario for altered BP variability, which might mediate the harmful effects of CAN. Preliminary data suggest the protective effect of targeting BP variability. However, further longitudinal outcome studies are needed. In the meantime, BP variability measures and practical expedients in antihypertensive treatment should be implemented in diabetes.

Orthostatic heart rate changes in patients with autonomic failure caused by neurodegenerative synucleinopathies

OBJECTIVE

Blunted tachycardia during hypotension is a characteristic feature of patients with autonomic failure, but the range has not been defined. This study reports the range of orthostatic heart rate (HR) changes in patients with autonomic failure caused by neurodegenerative synucleinopathies.

METHODS

Patients evaluated at sites of the U.S. Autonomic Consortium (NCT01799915) underwent standardized autonomic function tests and full neurological evaluation.

RESULTS

We identified 402 patients with orthostatic hypotension (OH) who had normal sinus rhythm. Of these, 378 had impaired sympathetic activation (ie, neurogenic OH) and based on their neurological examination were diagnosed with Parkinson disease, dementia with Lewy bodies, pure autonomic failure, or multiple system atrophy. The remaining 24 patients had preserved sympathetic activation and their OH was classified as nonneurogenic, due to volume depletion, anemia, or polypharmacy. Patients with neurogenic OH had twice the fall in systolic blood pressure (SBP; -44 ± 25 vs -21 ± 14 mmHg [mean ± standard deviation], p < 0.0001) but only one-third of the increase in HR of those with nonneurogenic OH (8 ± 8 vs 25 ± 11 beats per minute [bpm], p < 0.0001). A ΔHR/ΔSBP ratio of 0.492 bpm/mmHg had excellent sensitivity (91.3%) and specificity (88.4%) to distinguish between patients with neurogenic from nonneurogenic OH (area under the curve = 0.96, p < 0.0001). Within patients with neurogenic OH, HR increased more in those with multiple system atrophy (p = 0.0003), but there was considerable overlap with patients with Lewy body disorders.

INTERPRETATION

A blunted HR increase during hypotension suggests a neurogenic cause. A ΔHR/ΔSBP ratio < 0.5 bpm/mmHg is diagnostic of neurogenic OH. Ann Neurol 2018;83:522-531.