Preoperative screening for obstructive sleep apnea in cardiovascular patients – How useful is STOP-BANG questionnaire in the Indian context?

BACKGROUND: Obstructive sleep apnea (OSA) is reported in a high proportion of cardiac surgical patients, up to 73%. STOP-BANG is a validated questionnaire for screening of outpatients for OSA with high sensitivity. There is sparse literature from India regarding the prevalence of OSA in preoperative cardiovascular patients and the utility of screening tools. AIMS: We sought to study the utility of the STOP-BANG questionnaire as a screening tool for OSA in cardiovascular patients validating it with ambulatory level 3 polysomnography. MATERIALS AND METHODS: It was a prospective study where consecutive patients getting admitted for coronary artery bypass surgery (CABG) from August 2017–February 2019 were recruited. All the patients were screened with the STOP-BANG questionnaire. 53 patients underwent overnight level 3 polysomnography using Apnea-Link. Correlations were made between clinical symptoms, STOP-BANG score, and OSA severity, measured using Apnea hypopnea index (AHI). RESULTS: We had 120 patients(103 males) with a mean age 60 years. Snoring was the most common sleep complaint. Our cohort had a high prevalence of vascular risk factors (DM 72.3%, hypertension 59.2%, dyslipidemia 60%) and 11.7% were obese (BMI >30). The median STOP-BANG score was 3 (IQR 2) with 83 having scores ≥3. Median AHI was 5.6 with AHI ≥5 in 28 patients and AHI 15 or above in 14 patients. Among the clinical parameters, arousals with respiratory difficulty at night, higher neck circumference, and tonsillar hypertrophy showed a significant association with PSG-proven OSA.STOP-BANG scores 3 or above had a sensitivity of 75% in predicting OSA. CONCLUSIONS: Our study shows that in cardiovascular patients less symptomatic for sleep complaints, the STOP-BANG questionnaire is a useful screening tool for OSA in outpatient settings. Among clinical parameters, airway narrowing and neck circumference can predict OSA.