Respiratory and Haemodynamic Effects of Conscious Sedation With Dexmedetomidine for a TAVI Procedure

Summary

Transcatheter aortic valve implantation (TAVI) is now the standard procedure for elderly patients with severe aortic stenosis. This patient group is characterised by increased frailty, multiple comorbidities and limited physiological reserve, exposing them to an increased risk of intraoperative complications.

The majority of TAVI procedures are now performed under conscious sedation, in order to limit the risks associated with general anaesthesia and to promote a faster recovery. However, this strategy carries a risk of intraoperative respiratory events, notably bradypnoea, oxygen desaturation and airway obstruction, particularly in elderly patients with comorbidities.

The anaesthetic strategy, and in particular the type of sedation used, is likely to influence intraoperative respiratory and haemodynamic tolerance. Traditionally used agents, such as propofol combined with opioids, can induce dose-dependent respiratory depression. Conversely, dexmedetomidine, an α2-adrenergic receptor agonist, has a distinct pharmacological profile, characterised by sedation with a theoretically limited respiratory impact.

However, comparative data regarding the impact of different sedation strategies on intraoperative respiratory tolerance during TAVI remain limited, justifying the conduct of this study.

Dexmedetomidine is a selective α2-adrenergic receptor agonist, used in anaesthesia and intensive care for its sedative and anxiolytic properties. It induces what is known as 'cooperative' sedation, characterised by the maintenance of relative alertness, the possibility of interacting with the patient and, above all, a limited impact on spontaneous breathing.

Physiologically, dexmedetomidine differs from conventional sedatives, such as propofol and opioids, in causing less respiratory depression, making it a particularly attractive option for conscious sedation. This property is essential in elderly and comorbid patients, particularly during procedures such as TAVI, where maintaining spontaneous ventilation is a major concern.

Several clinical studies, particularly in procedural sedation and interventional cardiology, suggest that the use of dexmedetomidine is associated with better respiratory tolerance, with a reduction in episodes of desaturation, bradypnoea and the need for airway interventions, compared with strategies based on propofol and opioids.

However, data specific to the context of TAVI under conscious sedation remain limited, particularly regarding the prospective and standardised assessment of intraoperative respiratory events.

This study therefore aims to address this knowledge gap by assessing the effect of dexmedetomidine, compared with standard sedation using propofol-remifentanil, on intraoperative respiratory tolerance in patients undergoing TAVI under conscious sedation.

Conditions

• TAVI(Transcatheter Aortic Valve Implantation)

Interventions

DRUG

Sedation with dexmedetomidine

Loading dose (optional depending on tolerance): 0.5 µg/kg administered as a slow infusion over 10 minutes (no direct bolus to avoid bradycardia). Maintenance infusion: 0.2 to 0.7 µg/kg/h. Start at 0.4 µg/kg/h. Adjust in increments of 0.1-0.2 µg/kg/h depending on the level of sedation observed. Target: RASS -2 to 0 (patient calm, arable to verbal stimulation). Adjustment of sedation: If agitation/discomfort: * Increase Dexdor by 0.1 µg/kg/h. * If persistent: sufentanil bolus 2.5-5 µg. If significant drowsiness/bradycardia: * Reduce by 0.1 µg/kg/h. * If bradycardia \< 45 bpm: Pacemaker in place by surgical team If hypotension (SBP \< 90 mmHg): → Reduce flow rate and administer crystalloids ± vasopressor (noradrenaline)

DRUG

sedation propofol and remifentanil

Propofol and remifentanil will be administered via target-controlled infusion (TCI) pumps in accordance with standard pharmacokinetic models: Sedation will be titrated to maintain a RASS score between -2 and 0 (patient calm, arousable to verbal stimulation). Start the infusion at the lower target (propofol 0.5 µg/mL; remifentanil 1.0 ng/mL). Gradually adjust every 2-3 minutes based on RASS, signs of discomfort or pain, and haemodynamic and respiratory stability. If agitation/discomfort: Increase Propofol by 0.2 µg/ml and Remifentanil by 0.3 ng/ml If hypoventilation (EtCO₂ \> 50 or FR \< 8) : Reduce Propofol by 0.2 µg/ml or Remifentanil by 0.3 ng/ml. If bradycardia \< 45 bpm: Pacing If hypotension (SBP \< 90 mmHg): Reduce the infusion rate and administer crystalloids ± a vasopressor (noradrenaline) Maximum remifentanil dose: 2.5 ng/mL Maximum propofol dose: 1.5 µg/mL

Sponsors & Collaborators

• Erasme University Hospital

  lead OTHER

Principal Investigators

• celine Boudart · HUB - Erasme

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

60 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-04-22

Primary Completion

2027-05-30

Completion

2027-06-30

Countries

• Belgium

Study Locations