The Effect of Right Ventricular Arterial Uncoupling on Mortality in Cardiogenic Shock

Purpose The resistance compliance (RC) time describes the relationship between the pulmonary vascular resistance (PVR) and the pulmonary artery compliance (PAC) reflecting right ventricular (RV) afterload. Increased left atrial pressure shifts this relationship, lowering PAC for any given PVR leading to ventricular-arterial uncoupling and increased RV afterload. We hypothesize that decreased RC time is associated with increased in-hospital mortality due to poor right heart compensation in acute shock. Methods Admission right heart catheterization (RHC) data were analyzed in consecutive patients from 2014 to 2016 with cardiogenic shock as defined by a cardiac index Results We studied 235 patients with 265 unique encounters, where 15.3% died during the hospitalization. The mean RC time in our study sample was 0.33 (SD ±0.21). The hazard ratio (HR) for in-hospital mortality risk with the RC time was 0.161 (p-value = 0.07). Compared to the highest tertile, the lowest tertile of RC time was associated with increased mortality (HR 0.323, p-value = 0.045). The mortality risk persisted when adjusted for the RAP (HR 0.344, p-value = 0.056). The mean PAPi was 3.08 (SD ±3.79). The HR of in-hospital mortality with the PAPi was 0.806 (p-value = 0.166). Compared to the highest tertile, the lowest tertile of PAPi was associated with an increased mortality (HR 0.382, p-value = 0.045). This association was non-significant when adjusted for the RAP (HR 0.461, p-value = 0.202). Conclusion We demonstrate that a low RC time and increased RV afterload is associated with increased mortality in patients admitted with cardiogenic shock. In contrast to the PAPi, this association is independent of right atrial pressure, suggesting that the RC time may be a better marker of outcomes independent of central venous pressure. Further studies are needed to evaluate the role of these markers in cardiogenic shock.