Low Organ Perfusion Pressure Indexed to Body Surface Area is a Powerful Predictor of Poor Outcomes Even after Heart Transplantation in the Presence of High Right Atrial Pressure

Purpose High right atrial pressure (RAP) is associated with deranged renal function and mortality in patients with heart failure. We hypothesised that : 1.This effect may persist after heart transplantation 2. It is essentially mediated through a low organ perfusion pressure indexed to body surface area (OPPI). 3.That OPPI is more sensitive than organ perfusion pressure (OPP) alone in predicting survival. Methods The data from 250 patients who had a heart transplant over a 8 period from October 2012 to march 2020 was analyzed for the effect of OPPI and OPP. OPP was calculated as :Mean arterial pressure (MAP) - RAP and OPPI as (MAP-RAP)/body surface area .OPPI value of 40 and OPP of 60 mm hg were chosen for analysis as they were close to the median values. Results There was a more significant negative correlation between OPPI and creatinine (r = -0.3551,p =0.000) than OPP and creatinine (r = -0.0688,p = 0.3414).The effect of OPPI on MELD score was more pronounced than OPP.( r = -0.3580, p = 0.000 vs r = -0.1504, p = 0.062). OPPI also had a more significant effect on 90 day mortality than OPP (odds ratio 0.89, p = 0.004 vs odds ratio 1.01 ,p = 0.677). The 90 day mortality for OPPI less than and more than 40 was 23.2 % vs 7.1 %, p = 0.001.This effect of OPPI and OPP on 90 day mortality was absent if RAP was less than 15 mm hg. The effect of OPPI on survival persisted at a follow up of beyond 5 years. (72 % vs 54 % , p = 0.0124).The effect was absent if the RAP was less than 15. The effect was more pronounced for OPPI than OPP. Conclusion 90 day and 5 year survival after heart transplantation are worse in patients with low organ perfusion pressure indexed to BSA . OPPI less than 40 appears to be deleterious . Vasodilator drugs used to treat systolic left heart failure may adversely affect survival if RAP is high, to be used with caution.