The Clinical Significance of Portal Hypertension After Cardiac Surgery: a Multicenter Prospective Observational Study

The Clinical Significance of Portal Hypertension After Cardiac Surgery

Portal flow pulsatility detected by Doppler ultrasound is an echographic marker of cardiogenic portal hypertension from right ventricular failure and is associated with adverse outcomes based on previous studies performed at the Montreal Heart Institute. This multicenter prospective cohort study aims to determine if portal flow pulsatility after cardiopulmonary bypass separation is associated with a longer requirement of life support after cardiac surgery.

Hypothesis: Portal flow pulsatility detected by Doppler ultrasound during cardiac surgery is an echographic marker of cardiogenic portal hypertension from right ventricular failure and is associated with adverse clinical outcomes.

Background: Peri-operative right ventricular failure is associated with a high mortality rate. In this context, organ perfusion is hampered by both the reduction of cardiac output and venous congestion from the elevation of central venous pressure. The clinician's objective is to appreciate the hemodynamic impact on end-organs in an effort to adjust the therapy accordingly since the ultimate goal is to optimize their perfusion. Based on this rationale, organ specific blood flow assessment using Doppler ultrasound could be used to personalize management. In order to non-invasively assess the presence of cardiogenic portal hypertension, Doppler ultrasound can be used to detect portal flow pulsatility, an abnormal variation in the velocity of blood flow within the main portal vein. In two single-center cohort studies, the presence of portal flow pulsatility after cardiac surgery was independently associated with post-operative complications such as major bleeding, acute kidney injury (AKI) and delirium as well as increased length of intensive care unit (ICU) stay.

Specific Objectives: This multi-center cohort study aim to determine whether the association between portal flow pulsatility and organ dysfunction seen in previous studies is present across multiple cardiac surgery centers.

Inclusion Criteria:

• Adult patients (≥18 years old) and able to give informed consent undergoing cardiac surgery with the use of CPB for whom peri-operative TEE is planned.

• High surgical risk defined as at least one of the following:

  1. Multiple surgical procedures planned
  2. EuroSCORE II ≥ 5%
  3. Known pulmonary hypertension (mPAP>25mmHg or sPAP>40mmHg).

Exclusion Criteria:

• Patient with a critical pre-operative state defined as vasopressor requirement, mechanical circulatory support, dialysis, mechanical ventilation or cardiac arrest necessitating resuscitation.
• Patient with known condition that could interfere with portal flow assessment or interpretation (liver cirrhosis, portal vein thrombosis)
• Planned cardiac transplantation
• Planned ventricular assist device implantation