Pulmonary Artery Wedge Pressure Respiratory Variation Predicts Hemodynamic Improvement with Increased LVAD Speed

Abstract

IntroductionRespirophasic hemodynamic patterns are prognostic in the setting of heart failure (e.g. Kussmaul's sign), though the implications of hemodynamic respirophasic variation patterns in patients supported with a left ventricular assist device (LVAD) are unknown. Many LVAD patients remain poorly hemodynamically optimized, and the ability to optimize these patients with ramp speed increase is a positive prognostic marker. However, the response to ramp speed increase may be unpredictable. Alterations in hemodynamics with respiration may predict ramp speed response by reproducing pre-load alterations during respiration similar to LVAD speed manipulation.HypothesisAbsence of pulmonary artery wedge pressure (PAWP) respiratory variation in patients with LVADs is associated with an inability to reduce the PAWP with increasing pump speed. Absence of right atrial pressure (RAP) respiratory variation is a marker of right ventricular (RV) dysfunction.MethodsWe retrospectively collected data from 16 separate, consecutive hemodynamic ramp studies on 12 patients with HeartMate II LVADs (average 880 ± 483 days of LVAD support). All PAWP and RAP at inspiration and expiration were independently measured in a blinded fashion. Patient demographic and clinical data was obtained from chart review. No patient had clinically significant pulmonary disease.ResultsThe degree of respiratory variation of PAWP correlated with PAWP reduction with speed increase (R = 0.81). PAWP respiratory variation also correlated with the LV transmural pressure (PAWP - RAP) (R = 0.87) (Figure). Patients admitted for RV failure (n=6) within 60 days of the ramp study did not have significantly different RAP respiratory variation at baseline compared to those not admitted for RV failure (n=6) (27% versus 40%, p = 0.09). However, there was a difference in RAP respiratory variation at the peak speed of the ramp study (36% RAP respiratory variation in RV failure patients compared to 61% for non-RV failure patients, p = 0.045).ConclusionsThe degree of PAWP respiratory variation is correlated with the ability to unload the LV by increasing LVAD speed. PAWP respiratory variation is a marker of a favorable hemodynamic response to speed changes during ramp study. In addition, patients with reduced RAP respiratory variation were more likely to have RV failure requiring hospital admission. Right and left-sided filling pressure respiratory variation patterns can provide valuable clinical information to the treating physician regarding the LVAD patient's underlying biventricular physiology. Respirophasic hemodynamic patterns are prognostic in the setting of heart failure (e.g. Kussmaul's sign), though the implications of hemodynamic respirophasic variation patterns in patients supported with a left ventricular assist device (LVAD) are unknown. Many LVAD patients remain poorly hemodynamically optimized, and the ability to optimize these patients with ramp speed increase is a positive prognostic marker. However, the response to ramp speed increase may be unpredictable. Alterations in hemodynamics with respiration may predict ramp speed response by reproducing pre-load alterations during respiration similar to LVAD speed manipulation. Absence of pulmonary artery wedge pressure (PAWP) respiratory variation in patients with LVADs is associated with an inability to reduce the PAWP with increasing pump speed. Absence of right atrial pressure (RAP) respiratory variation is a marker of right ventricular (RV) dysfunction. We retrospectively collected data from 16 separate, consecutive hemodynamic ramp studies on 12 patients with HeartMate II LVADs (average 880 ± 483 days of LVAD support). All PAWP and RAP at inspiration and expiration were independently measured in a blinded fashion. Patient demographic and clinical data was obtained from chart review. No patient had clinically significant pulmonary disease. The degree of respiratory variation of PAWP correlated with PAWP reduction with speed increase (R = 0.81). PAWP respiratory variation also correlated with the LV transmural pressure (PAWP - RAP) (R = 0.87) (Figure). Patients admitted for RV failure (n=6) within 60 days of the ramp study did not have significantly different RAP respiratory variation at baseline compared to those not admitted for RV failure (n=6) (27% versus 40%, p = 0.09). However, there was a difference in RAP respiratory variation at the peak speed of the ramp study (36% RAP respiratory variation in RV failure patients compared to 61% for non-RV failure patients, p = 0.045). The degree of PAWP respiratory variation is correlated with the ability to unload the LV by increasing LVAD speed. PAWP respiratory variation is a marker of a favorable hemodynamic response to speed changes during ramp study. In addition, patients with reduced RAP respiratory variation were more likely to have RV failure requiring hospital admission. Right and left-sided filling pressure respiratory variation patterns can provide valuable clinical information to the treating physician regarding the LVAD patient's underlying biventricular physiology.