Influence of anesthesia on hemodynamic assessment of mitral stenosis severity

Background: The treatment of choice for severe rheumatic mitral stenosis (MS) is balloon mitral valvuloplasty (BMV). Assessment of MS severity is usually performed by echocardiography. Before performing BMV, invasive hemodynamic assessment is also performed. The effect of anesthesia on the invasive assessment of MS severity has not been studied. The purpose of the present study was to assess changes in invasive hemodynamic measurement of MS severity before and after induction of general anesthesia. Methods: The medical files of 22 patients who underwent BMV between 2014 and 2020 were reviewed. Medical history, laboratory, echocardiographic and invasive measurements were collected. Anesthesia induction was performed with etomidate or propofol. Pre-procedural echocardiographic measurements of valve area using pressure half time, and continuity correlated well with invasive measurements using the Gorlin formula. Results: After induction of anesthesia the mean mitral valve gradient dropped by 2.4 mmHg (p = 0.153) and calculated mitral valve area (MVA) increased by 0.2 cm² (p = 0.011). A wide variability in individual response was observed. While a drop in gradient was noted in 14 patients, it increased in 7. Gorlin derived MVA rose in most patients but dropped in 4. Assuming a calculated MVA of 1.5 cm² and below to define clinically significant MS, 4 patients with pre-induction MVA of 1.5 cm² or below had calculated MVA above 1.5 cm² after induction. Conclusions: The impact of general anesthesia on the hemodynamic assessment of MS is heterogeneous and may lead to misclassification of MS severity.