Surgery for heart failure: Treatment options and implications

In Vitro Pressure Measurements Across an Interatrial Shunt for HFpEF Treatment

PURPOSE

Preserved ejection fraction heart failure (HFpEF) can be treated by installing a shunt in the interatrial septum, which relieves excess pressure in the left atrium by allowing blood to flow from left to right. This technique has proven effective in clinical trials, but the details of the flow through the shunted heart are not well understood. The current study aims to collect quantitative data on the relationship between pressure and flow rate in such shunts.

METHODS

An in vitro, shunted double atrium flow phantom was fabricated and used to investigate the relationship between pressure drop and flow across an interatrial shunt. Flow rate was controlled and the resulting pressure drop across the shunt was measured for a variety of flow cases, including steady and pulsatile flow, flow rate waveforms typical of healthy and failing hearts, and low and high heart rates.

RESULTS

The results show a positive relationship between shunt flow rate and pressure drop which is more pronounced in steady flow than in pulsatile flow. Increasing heart rate increases the time-averaged pressure drop across the shunt but not the maximum pressure drop. For steady-flow cases, large changes in pressure drop resulting from moderate changes in flow rate suggest a flow regime transition during parts of the cardiac cycle. Comparison of time-averaged pulsatile flow pressure measurements with steady-flow measurements and two analytical plate-orifice models suggests that none approximate pulsatile flow accurately.

CONCLUSIONS

The flow rate/pressure drop relationship across an in vitro model of an interatrial shunt has been measured for a variety of physiologically relevant cases. Among other things, the results suggest that steady flow approximations to the heart's pulsatile flow should be used with caution and simplified theoretical models do not approximate the flow rate/pressure drop relationship accurately.

Postdischarge Functional Capacity, Health-Related Quality of Life, Depression, Anxiety, and Post-traumatic Stress Disorder in Patients Receiving a Long-term Left Ventricular Assist Device

BACKGROUND

There is a paucity of data on depression, anxiety and post-traumatic stress disorder after left ventricular assist device (LVAD) implantation. We designed an observational study to integrate these with functional capacity and health-related quality of life (HR-QOL) in surviving LVAD patients.

METHODS AND RESULTS

Consenting patients between 1 month and 9 years after LVAD implantation (n = 121) were screened for functional capacity (World Health Organization Disability Assessment Schedule 2.0 [WHODAS 2.0)]); HR-QOL (European Quality of Life [EQ-5D] and Visual Assessment Scales [EQ-VAS]), depression (Patient Health Questionnaire [PHQ-9], anxiety (Generalized Anxiety Disorder Scale [GAD-7]) and post-traumatic stress disorder (Impact of Event Scale Revised [IES-R]). Of the 94% of patients who consented, 34.7% reported impaired functional capacity (WHODAS 2.0 score of ≥25%), 23.1%-34.7% HR-QOL problems (domain EQ-5D of ≥3), 10.7% "poor health" (EQ-VAS of ≤40), 14.9% depression (PHQ-9 of >14), 11.7% suicidal ideation and 17.5% anxiety (GAD-7 of >10). Among these patients, 23.5% had a positive screen for post-traumatic stress disorder (IES-R of ≥24). An EQ-VAS of 80 or greater predicted good functional capacity (P < .001).

CONCLUSIONS

One-third of discharged LVAD patients reported impaired function, HR-QOL, and psychological issues. A standardized evaluation before and after LVAD implantation could facilitate psychologic prehabilitation, inform decision-making, and identify indications for mental health intervention.