Using Real-World Data to Understand Who Has Cardiovascular Benefits from Continuous Positive Airway Pressure: The Importance of Male Sex, Excessive Sleepiness, and Primary Prevention

OSA symptom subtypes and hypoxic burden independently predict distinct cardiovascular outcomes

Study objectives

Studies on obstructive sleep apnoea (OSA) have identified clinically relevant symptom-based subtypes and novel OSA-specific nocturnal hypoxic measures. Both traits are individually associated with cardiovascular outcomes, but evidence about their independent or shared effects is unknown. This study investigated the simultaneous contributions of OSA symptom subtypes and hypoxic burden (HB) on incident cardiovascular outcomes.

Methods

Sleep Heart Health Study participants with high-quality oxygen saturation, apnoea-hypopnea index (AHI) and symptom data were included. Participants with OSA (AHI ≥5 events·h-1) were grouped into symptom subtypes. HB was calculated from respiratory event-related hypoxia. Cox proportional hazards models assessed whether symptom subtypes and/or HB were independently associated with cardiovascular mortality and major adverse cardiovascular events (MACE).

Results

4396 participants free of cardiovascular disease were analysed, with median follow-up >11 years. Higher HB was associated with worse cardiovascular mortality (HR (95% CI): 1.63 (1.13-2.35); p=0.009) independently of symptom subtypes. Compared to those without OSA, the excessively sleepy OSA subtype had higher risk of incident MACE (1.62 (1.23-2.15); p<0.001), independently of HB. Among participants with moderate-severe OSA (AHI ≥15 events·h-1), excessively sleepy participants had higher risk of cardiovascular end-points compared to other subtypes, but HB was not associated with cardiovascular mortality or MACE risk.

Conclusion

OSA symptom subtypes and HB are independently associated with MACE and cardiovascular mortality, respectively. Thus, both are important for understanding OSA-related cardiovascular risk. Future studies using clinical samples including OSA therapy information that incorporate symptom subtypes and novel biomarkers, such as HB, could improve predictive models for cardiovascular disease risk.

The Effect of Surgical Therapy for Obstructive Sleep Apnea on Blood Pressure and Peripheral Arterial Tonometry

OBJECTIVE

To determine the effect of upper airway surgery on cardiovascular function in patients with obstructive sleep apnea (OSA).

STUDY DESIGN

A prospective, self-controlled study from 2018 to 2023.

SETTING

Two academic medical centers.

METHODS

Seventy-four patients underwent surgery for OSA, including: tonsillectomy, adenoidectomy, epiglottidectomy, modified uvulopalatopharyngoplasty, maxillary expansion, and maxillomandibular advancement. Twenty-four-hour ambulatory blood pressure (BP), peripheral arterial tonometry (PAT)-based home sleep study, and sleep-related patient-reported outcomes (PROs) were captured preoperatively and at 6 months postoperatively. Paired T-tests evaluated changes in outcomes after surgery.

RESULTS

Forty-one patients successfully completed preoperative and postoperative assessments. Patients were generally middle-aged (43.8 ± 12.5 years), obese (BMI 33.0 ± 5.8 kg/m2), male (68%), White (71%), and had severe OSA (apnea-hypopnea index [AHI] 33.9 ± 29.5 events/h). The 4% oxygen desaturation index (ODI) decreased from 30.7 ± 27.1 to 12.2 ± 13.6 events/h (P < .01) after surgery. There was no significant difference in 24-h BP following surgery, though clinically meaningful reductions in nocturnal systolic (-1.95 [-5.34, 1.45] mmHg) and nocturnal diastolic (-2.30 [-5.11, 0.52] mmHg) blood pressure were observed. Stratified analysis showed patients undergoing skeletal surgery (n = 17) demonstrated larger average reductions compared to those undergoing soft tissue surgery in nocturnal systolic (-4.12 [-7.72, -0.51] vs -0.10 [-5.78, 5.58] mmHg) and nocturnal diastolic (-3.94 [-7.90, 0.01] vs -0.90 [-5.11, 3.31] mmHg) pressures. No meaningful changes were observed in PAT Autonomic Index (PAI) measurements.

CONCLUSION

Surgical therapy for OSA did not demonstrate statistically significant improvements in 24-h BP. However, clinically meaningful reductions in nocturnal BP were observed, particularly in skeletal surgery patients, supporting the need for larger studies of cardiovascular outcomes following OSA surgery.