Calculated plasma volume status and outcomes in patients undergoing coronary bypass graft surgery

Abstract

ObjectivesCongestion is associated with worse outcomes in critically ill surgical patients but can be difficult to quantify noninvasively. We hypothesised that plasma volume status (PVS), estimated preoperatively using a validated formula that enumerates percentage change from ideal plasma volume (PV), would provide incremental prognostic utility after coronary artery bypass graft (CABG) surgery.MethodsIn this retrospective cohort study, patients who underwent CABG surgery (1999–2010) were identified from a prospectively collected database. Actual ([1-haematocrit] x [a+(b x weight [kg])]) and ideal (c x weight [kg]) PV were obtained from equations where a, b and c are sex-dependent constants. Calculated PVS was then derived (100% x [(actual−ideal)/ideal]).ResultsIn 1887 patients (mean age 67±10 years; 79% male; median European System for Cardiac Operative Risk Evaluation [EuroSCORE] 4), mean PVS was −8.2±9%. While 8% of subjects had clinical evidence of congestion, a relatively increased PV (PVS >0%) was estimated in 17% and correlated with lower serum sodium, higher EuroSCORE and a diagnosis of diabetes mellitus. A PVS≥5.6% was optimally prognostic and associated with greater mortality (HR: 2.31, p=0.009), independently of, and incremental to, EuroSCORE, New York Heart Association class and serum sodium. A PVS≥5.6% also independently predicted longer intensive care (β: 0.65, p=0.007) and hospital (β: 2.01, p=0.006) stays, and greater postoperative renal (OR: 1.61, p=0.008) and arrhythmic (OR: 1.29, p=0.03) complications.ConclusionsHigher PVS values, calculated simply from weight and haematocrit, are associated with worse inpatient outcomes after CABG. PVS could help refine risk stratification and further investigations are warranted to evaluate the potential clinical utility of PVS-guided management in patients undergoing CABG.

Impact of calculated plasma volume status on all-cause and cardiovascular mortality: 4-year nationwide community-based prospective cohort study

“…Taking these results into consideration, PVS could be a useful predictor of poor clinical outcome in patients with heart failure independently of ejection fraction. Annette et al reported that PVS greater than -5.6% is associated with adverse inpatient outcomes such as in-hospital death, postoperative complications and prolonged hospitalization in patients undergoing coronary bypass graft surgery [ 15 ]. Interestingly, their cut-off value for the absence of adverse outcomes was -5.6%.…”

“…Actual PV (aPV), ideal PV (iPV), and PVS were calculated by the following equations: aPV = (1-hematocrit)×[a+(b×weight (kg))] where hematocrit is a fraction (Men: a = 1530 and b = 41; women, a = 864 and b = 47.9); iPV = c×weight (kg) where c = 39 in men and c = 40 in women; and PVS = [(aPV-iPV)/iPV]×100% [14,15,18]. Normal range of PVS has not been defined yet.…”

“…Recently, plasma volume status (PVS), an index of the degree to which patients have deviated from their ideal plasma volume, is gaining attention in patients with heart failure. PVS is associated with cardiac events and mortality in patients with heart failure [ 13 – 15 ]. American College of Cardiology/American Herat Association guidelines have recommended volume status be assessed [ 16 ].…”

Impact of Subclinical Congestion on Outcome of Patients Undergoing Mitral Valve Surgery

“…The plasma volume status (PVS) as a surrogate parameter of congestion is known to directly correlate with increased mortality in patients with stable CHF and can be calculated using only three variables that are readily available for every patient undergoing cardiac surgery (hematocrit, bodyweight and gender) [ 6 , 7 , 8 ].…”

“…Recent literature has demonstrated that plasma volume status (PVS) can be calculated easily based on the patients’ weight, gender and hematocrit [ 7 ]. Furthermore, an elevated PVS is known to directly correlate with increased mortality in patients with stable CHF, and has been applied for risk stratification in patients undergoing coronary artery bypass graft surgery or transcatheter aortic valve replacement [ 8 , 9 ].…”