PURPOSE: To evaluate the relevance of different hemodynamic parameters in the etiology of Pulmonary Hypertension(PH)in patients with Obstructive Sleep Apnea(SA).
METHODS: More than 3300 consecutive polysomnograms(PSG) performed over a two year period at a large tertiary care facility were screened for OSA defined as Apnea-Hypopnea index(AHI)>5. Patients so identified (N=1900) were cross-matched with the transthoracic echocardiogram (TTE) and right heart catheterization (RHC) databases. PH on TTE was defined as right ventricular systolic pressure (RVSP) >40 mmHg and on RHC as mean pulmonary arterial pressure (mPAP) >25 mmHg.
RESULTS: A total of 373 patients underwent TTE of which 162 had PH by TTE criteria. The prevalence of PH in the overall OSA population was 8.5% and 43.4% among those who underwent TTE. Of this cohort, 59 patients underwent RHC and 40(67%) had PH. Mean mPAP was 33.7 mmHg, mean pulmonary vascular resistance (PVR) was 3.8 woods units, and mean PCWP was 16.6 mmHg. 32(80%) of the RHC patients had PCWP >15 mmHg and 22(56%) had PVR>3 woods units. Of the latter group 15 patients also had PCWP >15 mmHg. Mean PAP was associated with mPVR (r=0.35; p <0.0001) and mPCWP(r=0.17; p<0.0005). Among these 40 patients, RVSP was not reported in 8 patients and only 19(47.5%) had RVSP>40. Among the PSG variables, nocturnal desaturation (33% in PH vs 11% in patients without PH) was the only significant factor predicting PH. Other PSG variables including AHI were not significantly different.
CONCLUSION: Elevated PCWP and PVR appear to be significant contributors to the etiology of PH in patients with OSA.
CLINICAL IMPLICATIONS: In patients with OSA and left ventricular dysfunction, underlying PH should be carefully evaluated. Earlier and better intervention for OSA may delay the onset and course of PH.
DISCLOSURE: Roop Kaw, No Financial Disclosure Information; No Product/Research Disclosure Information