SESSION TYPE: DVT/PE/Pulmonary Hypertension Posters II
PRESENTED ON: Wednesday, October 24, 2012 at 01:30 PM - 02:30 PM
PURPOSE: The mean arterial pressure is a time-weighted average of pressure values in large systemic arteries during the cardiac cycle. Normally diastolic phase contributes more to the mean and augmentation is minimal in pulmonary circulation. However,as elastance increases, augmentation index (measure of resistance vessel stiffness) increases leading to larger contribution of systolic phase. Practical indicators of increased augmentation index may help to select a subgroup responsive to vasodilator therapy within WHO group 2,3 in which elevated PA pressures may be contributed by other factors than resistance vessel pathology such as venous hypertension and extrinsic compression of vasculature. We hypothesize that difference between computer derived mean PA pressure in time domain and calculated mean PA pressure using ( DPAP+1/3X SPAP-DPAP )formula ,here stated as, Δ mean PA may be a such indicator and predict the response to vasodilator therapy.
METHODS: 15 WHO group 2 or 3, class 3 to 4 PAH patients initiated on vasodilator therapy were reassessed in 12 weeks with 6 MWT ,functional reclassification and repeat RHC. Response was defined as >=30 m improvement or 1 functional class improvement. 11 vs 4 were responders .Baseline Δ mean PA of responders and nonresponders were compared using t-Test and correlation between baselineΔ mean PA and baseline PVR (dyne*sec/cm5) and 12 weeks % Δ in PVR were studied using pearson CQ .
RESULTS: The Δ mean PA was 4.5 mmHg among responders,whereas it was only 1.5mmHg among nonresponders.(p=0.002).The correlation between Δ mean PA and baseline PVR was weak, R=0.1 whereas correlation between Δ mean PA and 12 weeks % Δ in PVR was significant R=0.58.
CONCLUSIONS: The difference between computer derived mean PA pressure and calculated mean PA pressure using ( DPAP+1/3X SPAP-DPAP )formula ,Δ mean PA ,may be a practical surrogate of augmentation index in pulmonary arterial tree and may predict the response to PAH specific therapy
CLINICAL IMPLICATIONS: Analytic use of PA pressure data of cardiac cycle rather than subject to variation snopshot measurements may be useful in decision making for PAH management.
DISCLOSURE: Demir Baykal: Consultant fee, speaker bureau, advisory committee, etc.: speaker fee
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