68yo male with a smouldering periprosthetic knee infection considered unsalvageable, requiring AKA.
- Large MCA stroke (likely embolic) while on rivaroxaban, since changed to warfarin. Residual hemiparesis.
- T2DM HbA1c 6.1%
- Severe AS
- Previously known to be moderate.
- Rpt TTE at anaesthetic registrar’s request while an inpatient several months ago awaiting AKA (delayed as patient was not mentally ready for the procedure).
- TTE showed severe AS.
- Patient had an aortic balloon valvuloplasty
- Was due to have AKA soon after while off his anticoagulation however COVID resurgence delayed the procedure until now.
Balloon aortic valvuloplasty
- BMJ best practice
- First line therapy for clinically unstable patients or those with severe AS who require urgent non-cardiac surgery (due to the absence of requirement for anticoagulation, in contrast to aortic valve replacement, and the short recovery time)
- Re-stenosis rates are high at 6/12
- No proven mortality advantage however patients may have significant symptomatology and haemodynamic improvements, which may offer a window for more definitive care (if appropriate)
- Mortality ~ 3% from the procedure
- This patient’s AS was reduced to ‘moderate’ severity through the procedure.
- BMJ best practice
- Grading AS
- Classical descriptions using mmHg pressure gradient across valve and valve area
- Dimensionless index useful. This is the ratio of the LV outflow tract (LVOT) time-velocity integral to that of the aortic valve jet. DI does not require the calculation of LVOT cross-sectional area, which is a cause of erroneous assessment and underestimation of AVA
- This patient’s mean gradient did not meet the severe criteria but this may be due to LV failure (itself a sign of severe AS).
- Haemodynamic mx considerations under anaesthesia
- CO is preload dependent – adequate filling P needed for non-compliant LV
- Sinus rhythm with low normal HR needed for adequate filling time and LV myocardial perfusion.
- High/normal SVR and DBP to maintain coronary perfusion.
- Beware neuraxial -> drop in SVR and preload
- Adequate analgesia to prevent catecholamine surges.
- Proceed to OT