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.

Characteristics and usefulness of unintended premature ventricular contraction during invasive assessment of aortic stenosis.

BACKGROUND: Postextrasystolic potentiation (PESP)-associated augmentation in left ventricular-aorta pressure gradient (LVAoG) observed after incidental premature ventricular contraction (PVC) during resting echocardiography is similar to dobutamine stress echocardiography (DSE)-associated augmentation in LVAoG in patients with low-flow, low-gradient (LF-LG) aortic stenosis (AS). What is not known is whether a similar relationship exists when unintended PVC causes PESP during cardiac catheterization in patients with AS. METHODS: We retrospectively reviewed all catheterizations performed for patients with at least moderate AS who had LVAoG assessment. Univariate and multivariate analyses were conducted to determine the predictors of pre- and post-PVC mean LVAoG ≥ 40 mmHg. RESULTS: Between September 2015 to September 2017, of 140 individuals undergoing cardiac catheterization, 34 met study criteria. Mean pre-PVC gradient was 38.9 ± 22.8 mmHg. All patients exhibited PESP-associated augmentation of LVAoG by an average of 28 ± 12%. In multivariate analysis, the only significant predictor of post-PVC mean LVAoG ≥ 40 mmHg was preserved LV function (OR 6.81; 95% CI 1.41-32.82, p = 0.02). Inability to generate ≥ 40 mmHg of mean LVAoG post-PVC had 100% specificity for nonsevere AS in our observational cohort. CONCLUSIONS: Unintended but interpretable PVCs occurred in one in four patients with AS undergoing cardiac catheterization with measurable hemodynamics. All of our patients with PVCs, regardless of underlying LVEF, exhibited PESP-associated augmentation of LVAoG. Our exploratory analysis suggests that inability to generate ≥40 mmHg of mean LVAoG post-PVC is highly specific for nonsevere AS.