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Abstract

We wanted to thank Dr. Kanchi for his interest in our manuscript, “Grading Aortic Stenosis With Mean Gradient and Aortic Valve Area: A Comparison Between Preoperative Transthoracic and Precardiopulmonary Bypass Transesophageal Echocardiography.”1Whitener G. Sivak J. Akushevich I. et al.Grading aortic stenosis with mean gradient and aortic valve area: A comparison between preoperative transthoracic and precardiopulmonary bypass transesophageal echocardiography.J Cardiothorac Vasc Anesth. 2016; 30: 1254-1259Abstract Full Text Full Text PDF PubMed Scopus (14) Google Scholar Dr. Kanchi raises a salient point regarding the differential changes in intrathoracic pressure and left ventricular loading conditions during spontaneous versus positive-pressure controlled ventilation. Physiologic differences, precisely like the one he mentions, further highlight the need for a set of Doppler acquisition rules and/or grading guidelines tailored to the precardiopulmonary bypass (pre-CPB) environment, because it is different from the preoperative one. Simply applying valve guideline grading cutoffs developed from different imaging modalities (transthoracic echocardiography and catheterization) and a disparate clinical context is crude and, as our work has shown, fraught with inaccuracies. One way to minimize the effect of positive-pressure ventilation would be to hold respiration while performing Doppler acquisition of velocities and gradients. However, this would not mimic spontaneous breathing, nor would it eliminate the effects of general anesthesia. To Dr. Kanchi’s point, a dimensionless index (DI) becomes an excellent candidate for grading aortic stenosis (AS) under general endotracheal anesthesia precisely because it should compensate for changes in loading conditions. In the outpatient setting, a dimensionless index, at least at the severe AS level (DI<0.25), already has good validation for predicting outcome.2Rusinaru D. Malaquin D. Marechaux S. et al.Relation of dimensionless index to long-term outcome in aortic stenosis with preserved LVEF.JACC Cardiovasc Imaging. 2015; 8: 767-775Crossref Scopus (39) Google Scholar My current group has project(s) underway to evaluate whether the dimensionless index correlates across clinical contexts and imaging modalities among patients with varying degrees of AS. Validation of the DI during pre-CPB transesophageal echocardiography (TEE) would be a step forward for standardizing accurate AS assessment. We would invite others to validate pre-CPB TEE use of DI, as well as investigation of other load-independent ways to grade AS, so that we can develop “the best” way to grade AS during pre-CPB TEE. Grading Aortic Stenosis With Mean Gradient and Aortic Valve Area: A Comparison Between Preoperative Transthoracic and Precardiopulmonary Bypass Transesophageal EchocardiographyJournal of Cardiothoracic and Vascular AnesthesiaVol. 31Issue 2PreviewI was interested to read the article Grading Aortic Stenosis With Mean Gradient and Aortic Valve Area: A Comparison Between Preoperative Transthoracic and Precardiopulmonary Bypass Transesophageal Echocardiography published in a recent issue of the Journal.1 The American Heart Association/American College of Cardiology has published guidelines for decision-making on aortic valve replacement in patients with aortic stenosis (AS); these guidelines rely on symptoms, left ventricular (LV) function, mean pressure gradient (PGm), aortic valve area (AVA), and LV ejection fraction. Full-Text PDF