Comparison of Echocardiography and Invasive Transseptal Catheterization for Assessing Transvalvular Gradient in Patients with Surgical Aortic Valve Prostheses: Fact or Myth!

Background: Echocardiography is the primary assessment tool for follow-up in patients with aortic valve prostheses. However, there are concerns regarding the consistency between echocardiographic and invasive transvalvular gradients (TVG). This study utilized both noninvasive and invasive methods to compare the TVG in aortic valve prostheses. Methods: The study included fourteen patients who had previously undergone surgical aortic valve replacement [metallic (n=12) and bioprosthetic (n=2)]. All patients had moderate-to-severe TVGs, which were measured during follow-up echocardiography, and they underwent invasive transseptal catheterization. Invasive and echocardiographic TVGs were measured and compared. Results: The median interval between index valvular surgery and invasive TVG measurement was 6.7 (2.5-11.5) years. The median interval between echocardiographic and invasive TVG measurements was 7.2 (2-19) days. Only 12 (85.7%) patients were symptomatic during echocardiographic assessment. Maximum TVGs obtained by echocardiography were higher than invasive peak-to-peak TVGs (77.0±13.1 vs. 47.5±21.7 mmHg, p<0.05). There was a significant negative correlation between the echocardiography-based aortic valve area and the effective orifice area index with the catheter-based peak-to-peak aortic gradient (r=-0.64, p=0.014 and r=-0.63, p=0.015). Six patients (42,9%) who revealed severe catheter-based peak-to-peak aortic gradient underwent redo aortic valve surgeries. The cut-off value of EOAI of <0.50 cm2/m2 was found as the predictor of severe catheter-based peak-to-peak aortic gradient. Conclusions: In our preliminary cohort study, the TVGs of aortic valvular prostheses measured by echocardiography were significantly greater than those measured by invasive transseptal catheterization. During follow-up, invasive confirmation of echocardiographic moderate-to-severe TVG in selected patients with surgical aortic valvular prostheses may be considered.