For those who have been affected by a stroke, night apnea syndrome may be a risk factor for a new ischemic event. The data provided by a stroke research project (BASIC-Brain Attack Surveillance in Corpus Christi) from the University of Michigan (USA) gives new indications in this respect. Nighttime apnea has been associated with an increased risk of a second stroke and increased mortality. The conclusions of the research, a preliminary study, were presented at the International Congress on stroke of the American Stroke Association. We talk about this topic with Dr. Simona Marcheselli, Head of the Operating Unit for Emergency Neurology and Stroke Unit at the Humanitas Hospital.
The research was carried out on 842 individuals with an average age of 65 years, 47% of whom were women who had previously suffered an ischemic stroke, thus caused by a reduced inflow of blood. The nocturnal respiration of these patients was monitored with portable devices that detected an average of fourteen total or partial pauses in breathing per hour of sleep. 63% of participants were identified as a sleep apnea patient (at least ten breathing pauses per hour).
The population was followed on average for 584 days. At the end of the research, it was found that 10.7% of participants had suffered a second stroke, and just fewer than 15% had a fatal outcome. In addition, an association has also emerged between each additional pause in breathing per hour of sleep and a higher risk of 9% of a second stroke or mortality.
A little less than 60% of the individuals involved were of Mexican origin (the BASIC project focuses in particular on this group of individuals, the largest segment of the U. S. Hispanic-American population). For these subjects, the risk of second stroke or mortality was greater than 1.7 times.
Night apnea and cardiovascular risk
Night apnea syndrome is a sleep breathing disorder characterized by interrupted breathing for a few seconds, several times every hour of sleep, due to partial or total obstruction of the upper airways. Several scientific evidence have associated this syndrome with a cardio-cerebrovascular risk profile: “There is a long known, strong correlation between sleep apnea and hypertension and above all cardiac arrhythmia, two important risk factors for stroke,” Dr. Marcheselli recalls. That’s why nighttime apnea syndrome can also have a negative impact on post-stroke recovery, aggravate the damage caused by stroke itself and increase the risk of recurrence.
In terms of recurrence, the prevention of a second stroke is done by avoiding or correcting all cardio-cerebrovascular risk factors such as cigarette smoking, hypertension, hypercholesterolemia, excess body weight, diabetes, and atrial fibrillation. Some of these are the elements that make up the framework of the metabolic syndrome that is often associated with night apnea syndrome and must be controlled. In the event of a new ischemic event or if an adequate prevention has not been made on this front, there may have been a different cause also linked to the therapy defined after the first stroke”, concludes Dr. Marcheselli.