"Hypotension Probability Indicator" in TAVI/MitraClip for Hypotension Management

The perioperative period is characterized by hemodynamic instability. Intraoperative hypotension (IOH) can be caused by anesthesia drugs, surgical manipulations, hypovolemia or inhibition of the sympathetic nervous system and impairment of baroreflex regulatory mechanisms. In a retrospective analysis performed at the Cleveland Clinic, the risk for acute kidney injury(AKI) and myocardial injury (MI) increased when mean arterial pressure (MAP) was less than 55 mmHg. Further, even short durations of intraoperative hypotension were associated with AKI and MI. Salmasi and coll analyzed whether associations based on relative thresholds were stronger than those based on absolute thresholds regarding blood pressure. They found that there were no clinically important interactions between preoperative blood pressures and the relationship between hypotension and MI or AKI at intraoperative mean arterial blood pressures less than 65 mmHg. Absolute and relative thresholds had comparable ability to discriminate patients with MI or AKI from those without it. The authors concluded that anesthetic management can thus be based on intraoperative pressures without regard to preoperative pressure. In a retrospective cohort study Sun and coll conclude that an increased risk of postoperative stage I AKI occurs when intraoperative MAP was less than 60 mmHg for more than 20 min and less than 55 mmHg for more than 10 min.

Hence it is fundamental for the management of any hemodynamically unstable patient the rapid assessment of the factors that determine the cardiovascular collapse, followed by prompt treatment and, ultimately, reversal of the responsible process. Recently a Hypotension Probability Indicator (HPI) algorithm has been developed from Edwards Lifesciences using continuous invasively-measured arterial waveforms to predict hypotension with high accuracy minutes before blood pressure actually decreases. The HPI algorithm can be integrated with a goal-directed hemodynamic treatment (GDHT) to achieve hemodynamic optimization by increasing global blood flow and prevent organ failure. The HPI index, combined with a hypotension management protocol, has shown efficacy in reducing hypotension during surgical procedures. Its effectiveness has been demonstrated in ICU patients with Covid-19. Studies in cardiac surgery cases have been conducted, with ongoing research in cardiac surgery patients (HYPE2 and HPI Care Trial). Maintaining stable arterial pressure and avoiding intraoperative hypotension are crucial during TAVI or MitraClip procedures, achieved through monitored anesthesia care (MAC) or general anesthesia. Based on recent publications and Pinsky's work, a hypotension management protocol integrating GDHT with the HPI algorithm has been developed for TAVI or MitraClip patients.

Inclusion criteria

• Age >18 years
• Will be monitored intraoperatively for >1 hour or will receive general anesthesia for >1 hour
• Will undergo intraoperative monitoring with invasive arterial pressure measurement
• Mean arterial pressure (MAP) target will be ≥ 65 mmHg intraoperatively
• Will sign written informed consent preoperatively
• Will undergo TAVI or Mitral Clip under general anesthesia or monitored anesthesia care (MAC) and sedation
• American Society of Anesthesiologists (ASA) Physical Status ≤ 4

Exclusion criteria

• Target for MAP different from 65 mmHg
• Severe hypotension preoperatively MAP <65 mmHg
• Severe heart failure (e.g., Left Ventricular Ejection Fraction<20%)
• Patients needing or will need mechanical circulatory support postoperatively (e.g., intra-aortic pump)
• Urgent surgery
• Patients with severe pulmonary hypertension (preexisting or detected intraoperatively)
• Patients with hemodynamic instability requiring extracorporeal circulation support