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Syed Moin Hassan, MD



Research Staff




Sleep and Circadian Disorders


Syed Moin Hassan*, Wolfgang Ganglberger, Ali Azarbarzin, MaryEllen C. Antkowiak, Jessica B. Badlam, Imama Ahmad,Farbod N. Rahaghi, George R Washko, M. Brandon Westover, Susan Redline, Brian E. Cade

Principal Investigator

Brian E. Cade


Polysomnography-derived hypoxemic markers associated with pulmonary hypertension in obstructive sleep apnea


Introduction: In this retrospective cohort study, we sought to explore if polysomnographic-derived markers of hypoxemia are associated with the presence of PHTN.

Methods: This was a retrospective nested case control study done at a large tertiary care center in Boston using data derived from electronic medical records (IRB (No. 2019P001283)).

We used Research Patient Data Registry, during the initial screening, to identify 7526 patients aged 18 years or more with OSA and presence of at least 1 in-laboratory polysomnography (in-lab PSG) done at Massachusetts General Hospital between 2008 and 2020. Out of the 7526 patients, 1860 patients were excluded due to the following reasons: apnea hypopnea index (AHI) less than 5 on the in-lab PSG (n=1622), patients who had an additional diagnosis of Group 1 PHTN (n=224) and sickle cell disease (n=14). The remaining 5666 patients were divided into PHTN cases (n=578) and PHTN controls (n = 5088), using an artificial intelligence (AI) computed phenotypic algorithm (AUC: 0.789 PPV: 0.93).

We used 1:3 propensity matching using age, BMI, gender, and presence of congestive heart failure, and obstructive lung disease to match 570 PHTN cases with 1710 PHTN controls.
The oximetry signals from in-lab PSGs were extracted and processed to derive additional hypoxemic metrics including sleep apnea-specific hypoxic burden (SASHB), T90, T90desaturation (T90 desat), and T90non-specific (T90non-spec).

Results: The fifth quintile of SASHB, T90, T90 desat, and T90non-spec were statistically significant at predicting the presence of PHTN with an OR of 1.60, 1.56, 1.52, 1.62 respectively while AHI was not statistically significant with an OR of 1.26. These associations persisted after adjusting for age, gender, BMI, smoking status, presence of obstructive lung disease, interstitial lung disease, and congestive heart failure in subsequent models

Conclusion: Multiple markers of overnight hypoxemia, but not AHI, were associated with the presence of PHTN.

Clinical Implications

– A subset of patients with obstructive sleep apnea (OSA) have severe pulmonary hypertension (PHTN) and are at risk for increased mortality and decreased quality of life. – Identifying this subset of patients would be useful for treatment, surveillance & risk factor modification.
-In summary, alternative inlab-PSG derived markers are associated with PH while AHI does not show any association. This predictive ability is potentially driven by their ability to better characterize hypoxemia. These findings build on prior studies demonstrating the utility of these alternative inlab-PSG derived markers in predicting cardiovascular morbidity and mortality and may show utility in subphenotyping and prognostication in patients with obstructive sleep apnea.