after surgery, according to a retrospective analysis.
This is one of the few studies to have ever examined whether adenotonsillectomy for children with OSA had any effects on blood pressure (BP) and was based on “one of the largest cohorts for evaluating postoperative BP changes in nonobese children with OSA,” noted Cho-Hsueh Lee, MD, and colleagues. The report was published in JAMA Otolaryngology–Head & Neck Surgery. Among the previous studies that evaluated BP in children with OSA before and after having this surgery, the results varied, they added.
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The researchers analyzed the medical records of 240 nonobese children with clinical symptoms and polysomnography-confirmed OSA (having an apnea-hypopnea index of greater than 1) who underwent adenotonsillectomy. Prior to surgery, 169 patients (70.4%) of the patients were classified as nonhypertensive, while 71 (29.6%) were classified as hypertensive. The children had a mean age of 7.3 years, and 160 were males.
Patients participated in full-night polysomnography (PSG) before surgery and at 3-6 months after adenotonsillectomy in the National Taiwan University Hospital Sleep Center. Apnea episodes were defined as a 90% decrease in airflow for two consecutive breaths. Sleep center staff measured the study participants’ systolic and diastolic BP in a sleep center using an electronic sphygmomanometer, in the evening, prior to the PSG study, and in the morning. Pediatric hypertension was based on the nocturnal BP measurement and was defined as having mean systolic and diastolic BP greater or equal to the 95th percentile for age, sex, and height.
“Postoperatively, hypertensive children had a significant decrease in all BP measures, including nocturnal and morning [systolic] BP ... A total of 47 hypertensive patients (66.2%) became nonhypertensive after surgery,” the researchers said.
For patients who were hypertensive before surgery, the average nocturnal (before PSG) preop systolic BP was 114.3 mm Hg, versus 107.5 mm Hg after surgery. The mean nocturnal diastolic BP for this same group of patients decreased to 65.1 mm Hg from 74.3 mm Hg. Similarly, the average morning (after PSG) systolic BP and diastolic BP were 106.0 mm Hg and 64.4 mm Hg after these patients underwent adenotonsillectomy, compared with 111.8 mm Hg and 71.7 mm Hg prior to surgery, respectively.
The adenotonsillectomy didn’t improve all patients’ BP. For some who were nonhypertensive before surgery, blood pressure increased, with 36 (21.3%) of this group having become hypersensitive after surgery, the researchers acknowledged.
Overall, the cohort experienced significant improvements in several PSG measures, including the average apnea-hypopnea index, which decreased from 12.1 events per hour to 1.7. The total arousal index also declined, going from 6.1 events per hour to 4.2. In addition, the mean oxygen saturation improved from 96.8% to 97.7%.
The investigators described several limitations of the study, including their inability to collect patients’ arterial stiffness, carotid intima thickness, and other cardiovascular measures beyond BP.
They recommended a follow-up study. “Although we observed improvements in BP measures within 6 months after surgery for hypertensive children with OSA, the long-term effects of surgery on BP remain uncertain,” they explained.
The study was supported by grants from the Ministry of Science and Technology, Republic of China (Taiwan). The researchers disclosed no potential conflicts of interest.
SOURCE: Lee, C-H et al. JAMA Otolaryngol Head Neck Surg. 2018 Feb 15. doi: 10.1001/jamaoto.2017.3127.