Estimation of Pulmonary Capillary Wedge Pressure from the HVAD Waveform and Its Prognostic Implications

Purpose Flow waveform visualization is a unique feature of the HVAD left ventricular assist device (LVAD) that provides graphical real-time information linking device performance with patient hemodynamics. A previous study demonstrated a good correlation between the slope of the ventricular filling phase (VFPS) and the pulmonary capillary wedge pressure (PCWP). We aimed to validate the utility of VFPS to estimate PCWP and predict clinical outcomes. Methods In this prospective blinded study, screenshots from the HVAD monitor and simultaneous invasive hemodynamic measurements were obtained. Each screenshot was digitized (IGOR Pro, WaveMetrics Inc., Oswego, OR) and the VFPS was calculated for each screenshot (Figure 1A) by two independent readers who were blinded to the hemodynamic results. VFPS and the estimated PCWP [using the previously derived equation: PCWP = 7.05 +1.38 × (VFPS)] were correlated to the measured PCWP. Association between VFPS and heart failure (HF) readmission rates was evaluated. Results 107 sets of simultaneous measurements (VFPS and PCWP) were performed (mean age 55 years, 47% male). Prospectively collected VFPS had a very strong and significant correlation with PCWP (p 2  = 0.69). The previously proposed cutoff of VFPS ≥5.8 L/min/sec predicted PCWP ≥18 mmHg with 91.5% sensitivity and 95.2% specificity. The previously derived equation had significant correlation with measured PCWP (p 2  = 0.68; Figure 1B) and acceptable agreement with the measured PCWP (Figure 1C). Patients with VFPS ≥5.8 L/min/sec had significant higher HF readmission rates than those with VFPS Conclusion VFPS of the HVAD flow waveform is a novel noninvasive parameter that can estimate PCWP and predict HF readmissions. VFPS may aid in clinical management of HVAD patients and serve as a step in the development of a smart LVAD pump.