Biomarker of breathing control abnormality associated with hypertension and stroke

July 01, 2009

Westchester, Ill. --A study in the July 1 issue of the journal SLEEP identified a distinct ECG-derived spectrographic phenotype, designated as narrow-band elevated low frequency coupling (e-LFCNB), that is associated with prevalent hypertension, stroke, greater severity of sleep disordered breathing and sleep fragmentation in patients suffering from obstructive sleep apnea (OSA).

Results indicate that the odds ratio for prevalent stroke was 1.65 [CI: 1.19𔃀.29] in those with versus without the presence of e-LFCNB. The biomarker was detected in 1,233 participants (23.5 percent), with statistically significant differences between those with and without it. Patients with the biomarker tended to be older (average 64.7 years versus 61.4 years), male (63.3 percent versus 45.1 percent), slightly heavier (average body mass index 29.3 versus 28.6) and sleepier (according to the Epworth Sleepiness Score test results). Sleep apnea severity and use of diuretics, calcium blockers, and B-blockers were associated with increased e-LFCNB. After adjustment for age, sex, body mass index, hypertension, and diabetes, only prevalent stroke remained associated with both categorical and continuous measures of e-LFCNB, while treated and total hypertension were associated only with the ECG biomarker as continuous measure.

According to lead author Robert J. Thomas, MD, assistant professor of medicine at the Beth Israel Deaconess Medical Center & Harvard Medical School in Boston, Mass., the electrocardiogram (ECG)-based technique allows the tracking of interactions ("coupling") of breathing amplitude and heart-beat rate changes, which are both influenced by sleep, thus providing a 'map' of sleep behaviors. Use of this technique allows physicians to assign patients with sleep apnea into groups who have or do not have breathing control abnormalities.

"Central sleep apnea is precisely timed, meaning that breathing stops and starts with near identical timing from event-to-event," said Thomas. This type of timing abnormality results in the narrow-band pattern, even if by usual scoring methods the respiratory abnormality looks obstructive." We found that having the pattern suggesting a central or breathing control abnormality was associated with worse sleep, more severe sleep apnea, high blood pressure and an increased risk of prevalent strokes. Therefore, OSA patients who are at increased risk for high blood pressure may be at even greater risk if they also have a control abnormality."

The cross-sectional retrospective study obtained polysomnographic and clinical data from 5,247 patients (of the original 6,441) who were included in the baseline examination of the Sleep Heart Health Study (SHHS), a multi-center longitudinal study of participants over the age of 40, designed to determine the cardiovascular consequences of sleep apnea at a population level. Associations were estimated with use of various drugs and pathologies including prevalent hypertension and cardiovascular and cerebrovascular disease.

According to the study, the ECG-derived spectrogram's detection of periodic breathing-type respiratory oscillations exceeds that identified by visual detection of periodic breathing. Conventional scoring may be biased toward the scoring of obstructive hypopneas during periods of periodic breathing, and measurement of the biomarker could bring attention to parts of the polysomnogram where the probability of periodic breathing or central apneas is high. The spectrogram is automated, objective, and capable of mapping the spectral dispersion of low-frequency, coupled cardiopulmonary oscillations; therefore, it could be a more accurate marker of periodic breathing and could provide insights into sleep physiology and pathology.

The authors claim that there is an increased prevalence of periodic breathing following ischemic cerebrovascular disease, which is one way by which strokes may cause an increase in the biomarker. Hypertension may be the cause of undiagnosed cardiac dysfunction, which may also lead to an increase in the presence of e-LFCNB.
-end-
According to the American Academy of Sleep Medicine, OSA is a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe. It occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing that can produce abrupt reductions in blood oxygen saturation. Brief arousals from sleep restore normal breathing but can cause a fragmented quality of sleep. Most people with sleep apnea snore loudly and frequently, and they often experience excessive daytime sleepiness.More information about OSA is available from the AASM at http://www.sleepeducation.com/Disorder.aspx?id=7.

SLEEP is the official journal of the Associated Professional Sleep Societies, LLC (APSS), a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society. The APSS publishes original findings in areas pertaining to sleep and circadian rhythms. SLEEP, a peer-reviewed scientific and medical journal, publishes 12 regular issues and 1 issue comprised of the abstracts presented at the SLEEP Meeting of the APSS.

For a copy of the study, "Prevalent Hypertension and Stroke in the Sleep Heart Health Study: Association with an ECG-derived Spectrographic Marker of Cardiopulmonary Coupling," or to arrange an interview with the study's author, please contact Kelly Wagner, AASM public relations coordinator, at (708) 492-0930, ext. 9331, or kwagner@aasmnet.org.

AASM is a professional membership organization dedicated to the advancement of sleep medicine and sleep-related research. As the national accrediting body for sleep disorders centers and laboratories for sleep related breathing disorders, the AASM promotes the highest standards of patient care. The organization serves its members and advances the field of sleep health care by setting the clinical standards for the field of sleep medicine, advocating for recognition, diagnosis and treatment of sleep disorders, educating professionals dedicated to providing optimal sleep health care and fostering the development and application of scientific knowledge.

American Academy of Sleep Medicine

Related Stroke Articles from Brightsurf:

Stroke alarm clock may streamline and accelerate time-sensitive acute stroke care
An interactive, digital alarm clock may speed emergency stroke care, starting at hospital arrival and through each step of the time-sensitive treatment process.

Stroke patients with COVID-19 have increased inflammation, stroke severity and death
Stroke patients who also have COVID-19 showed increased systemic inflammation, a more serious stroke severity and a much higher rate of death, compared to stroke patients who did not have COVID-19, according a retrospective, observational, cross-sectional study of 60 ischemic stroke patients admitted to UAB Hospital between late March and early May 2020.

'Time is vision' after a stroke
University of Rochester researchers studied stroke patients who experienced vision loss and found that the patients retained some visual abilities immediately after the stroke but these abilities diminished gradually and eventually disappeared permanently after approximately six months.

More stroke awareness, better eating habits may help reduce stroke risk for young adult African-Americans
Young African-Americans are experiencing higher rates of stroke because of health conditions such as high blood pressure, diabetes and obesity, yet their perception of their stroke risk is low.

How to help patients recover after a stroke
The existing approach to brain stimulation for rehabilitation after a stroke does not take into account the diversity of lesions and the individual characteristics of patients' brains.

Kids with headache after stroke might be at risk for another stroke
A new study has found a high incidence of headaches in pediatric stroke survivors and identified a possible association between post-stroke headache and stroke recurrence.

High stroke impact in low- and middle-income countries examined at 11th World Stroke Congress
Less wealthy countries struggle to meet greater need with far fewer resources.

Marijuana use might lead to higher risk of stroke, World Stroke Congress to be told
A five-year study of hospital statistics from the United States shows that the incidence of stroke has risen steadily among marijuana users even though the overall rate of stroke remained constant over the same period.

We need to talk about sexuality after stroke
Stroke survivors and their partners are not adequately supported to deal with changes to their relationships, self-identity, gender roles and intimacy following stroke, according to new research from the University of Sydney.

Standardized stroke protocol can ensure ELVO stroke patients are treated within 60 minutes
A new study shows that developing a standardized stroke protocol of having neurointerventional teams meet suspected emergent large vessel occlusion (ELVO) stroke patients upon their arrival at the hospital achieves a median door-to-recanalization time of less than 60 minutes.

Read More: Stroke News and Stroke Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.