Catheter-induced postextrasystolic potentiation in the assessment of severity of low-gradient aortic valve stenosis

Background: Deciphering which patients with low-gradient aortic valve disease have severe stenosis can be difficult. We aimed to correlate the postextrasystolic potentiation (PESP) with dobutamine stress echocardiography and multidetector computed tomography in patients with low-gradient aortic valve stenosis. Methods: Patients with an aortic valve area ≤1 cm2 and a mean gradient <40 mm Hg were included. Aortic valve stenosis severity was assessed by a core lab with dobutamine stress echocardiography, followed by a multidetector computed tomography aortic valve score if indeterminate. A premature ventricular contraction was induced by intentional catheter contact with the myocardium within the left ventricle. PESP was calculated as a percent change of pre-to-post mean gradient. Multidetector computed tomography was used to measure the aortic valve calcification score, and subsequently, aortic valve calcification density. Results: Twenty-eight patients (age, 77±10 years; 19 female) were included. Dobutamine stress echocardiography increased mean gradient from baseline of 25±7 mm Hg to 36±11 mm Hg; pre-premature ventricular contraction mean gradient was 25±7 mm Hg and increased to post-premature ventricular contraction mean gradient of 32±10 mm Hg, representing a PESP of 24±11%. A ≥20% in PESP resulted in 100% sensitivity, 77% specificity, 83% positive predictive value, and 100% negative predictive value for diagnosing severe aortic valve stenosis. There was a significant correlation between PESP and projected aortic valve area and aortic valve calcification density (R=−0.64, P=0.0003; R=0.057, P=0.014, respectively). Conclusions: In patients with low-gradient aortic valve stenosis, catheter-induced premature ventricular contractions during cardiac catheterization causing ≥20% PESP has a 100% sensitivity for severe aortic valve stenosis. Validation of this 20% cutoff in larger groups with correlation to clinical end points is required.