Hyponatremia accompanying volatile hypertension caused by baroreflex failure after neck surgery: case report and literature review

Ambulatory central BP and arterial stiffness in patients with and without intradialytic hypertension

BACKGROUND

Increased arterial stiffness is suggested to be involved in the pathogenesis of intradialytic-hypertension (IDH). Ambulatory pulse-wave-velocity (PWV) is an independent predictor for all-cause-mortality in haemodialysis and its prognostic power is better than office PWV. This is the first study examining ambulatory central blood pressure (BP) and arterial stiffness parameters in patients with and without IDH.

METHODS

This study examined 45 patients with IDH (SBP rise ≥10 mmHg from pre- to post-dialysis and post-dialysis SBP ≥150 mmHg) in comparison with 197 patients without IDH. All participants underwent 48-h ABPM with Mobil-O-Graph-NG; parameters of central haemodynamics, wave reflection and PWV were estimated.

RESULTS

Age, dialysis vintage and interdialytic weight gain did not differ between-groups. IDH patients had higher 48-h cSBP (131.7 ± 16.2 vs. 119.2 ± 15.2 mmHg, p < 0.001), 48-h cDBP (86.7 ± 12.7 vs. 79.6 ± 11.5 mmHg, p < 0.001) and 48-h cPP (45.5 ± 10.4 vs. 39.8 ± 10.0 mmHg, p = 0.001) compared to patients without IDH. Similarly, during day- and nighttime periods, cSBP/cDBP and cPP levels were higher in IDH-patients compared to non-IDH. Forty-eight-hour augmentation pressure and index, but not AIx(75) were higher in IDH patients; 48-h PWV (10.0 ± 2.0 vs. 9.2 ± 2.1 m/s, p = 0.017) was significantly higher in patients with IDH. The two study groups displayed different trajectories in central BP and PWV over the course of the recording; IDH patients had steadily high values of the above variables during the 2 days of the interdialytic-interval, whereas non-IDH patients showed a gradual elevation, with significant increases from the 1st to 2nd 24 h.

CONCLUSIONS

IDH patients have significantly higher levels of ambulatory central BP and arterial stiffness parameters and a different course over the 48-h period compared with non-IDH patients. Increased arterial stiffness could be a prominent factor associated with the high burden of cardiovascular disease in this population.

Impaired vagal adaptation to an exercise task in women with gestational diabetes mellitus versus women with uncomplicated pregnancies

PURPOSE

Gestational diabetes mellitus (GDM) is associated with an increased risk for maternal and fetal complications. Patients with GDM have an increased cardiovascular risk in later life. The aim of this study was to investigate cardiac autonomic nervous system (ANS) function at rest and during exercise in women with GDM vs. women with uncomplicated pregnancies.

METHODS

Thirty-six normotensive pregnant women (21 with GDM and 15 age- and parity-matched women with an uncomplicated pregnancy) were enrolled in this case-control study. Continuous beat-by-beat blood pressure (BP) measurements were recorded during rest, intermittent handgrip exercise, and recovery (via photoplethysmography, Finapres®). Heart rate variability (HRV) (Kubios®) was used for the assessment of autonomic nervous system function.

RESULTS

The groups were similar in age, gestational week, and handgrip strength. At rest, no differences in HRV indices [root mean square of successive differences (RMSSD), standard deviation Poincaré plot 1, and 2 (SD1, SD2), SD2/SD1 ratio] were detected between women with GDM and women with an uncomplicated pregnancy. However, during exercise, a different pattern in the HRV responses was detected: in the control group, RMSSD and SD1 (indices of parasympathetic function) significantly decreased (p < 0.001) during handgrip exercise and returned to baseline during recovery. In contrast, in GDM, the above HRV indices remained unaltered throughout the protocol.

CONCLUSION

Normotensive women with GDM present impaired parasympathetic system ability to adapt to an exercise stimulus, as suggested by the blunted sensitivity in RMSSD and SD1. This finding suggests early alterations in ANS may exist in women with GDM, even when no differences are detected in resting conditions.

Natural History of Afferent Baroreflex Failure in Adults

OBJECTIVE

To describe the natural history of afferent baroreflex failure (ABF) based on systematic review of clinical and laboratory data in patients with a diagnosis of ABF at Mayo Clinic Rochester.

METHODS

We performed a retrospective chart review of all patients who underwent standardized autonomic reflex testing between 2000 and 2020 and had confirmation of the diagnosis of ABF by an autonomic disorders specialist. Patients were identified using a data repository of medical records. Variables included demographic, all-cause mortality, medications, ABF manifestations, comorbidities, and laboratory (autonomic testing, blood pressure monitoring, echocardiogram, brain imaging, plasma catecholamines, serum sodium level, and kidney function tests).

RESULTS

A total of 104 patients with ABF were identified. Head and neck radiation was the most common etiology (86.5%), followed by neck surgery (5.8%) and other causes (7.7%). The most common findings were hypertension (87.5%), fluctuating blood pressure (78.8%), orthostatic hypotension (91.3%), syncope (58.6%), headache (22.1%), and tachycardia (20.2%). Patients commonly received antihypertensives (66.3%), pressor agents (41.3%), or a combination of both (19.2%). The median latency from completion of radiation to ABF was longer compared to the latency in the surgery group (p < 0.0001). Comorbidities, including complications from neck radiation, were frequently seen and all-cause mortality was 39.4% over a 20-year period.

CONCLUSIONS

ABF should be suspected in patients with prior head and neck cancer treated by radiation or surgery who present with labile hypertension and orthostatic hypotension. Management may require both antihypertensive and pressor medications. The morbidity and mortality in ABF are high.