Prognostic Usefulness of Cardiopulmonary Exercise Testing for Managing Patients With Severe Aortic Stenosis

Abstract

The approach to managing asymptomatic or questionably symptomatic patients for aortic stenosis is difficult. We aimed to determine whether cardiopulmonary exercise testing (CPET) is prognostically useful in such patients. Patients judged asymptomatic or questionably symptomatic for aortic stenosis with aortic valve area index <0.6 cm/m and left ventricular ejection fraction ≥0.50 were managed conservatively provided they had either (group 1) normal peak oxygen consumption and peak oxygen pulse (>83% and >95% of the predicted values, respectively) or (group 2) subnormal peak oxygen consumption or peak oxygen pulse but with CPET data pointing to pathologies other than hemodynamic compromise from aortic stenosis. Increase in systolic blood pressure <20 mm Hg, ST depression ≥2 mm, or symptoms during the exercise test were allowed. Unexpected events included cardiac death or hospitalization with heart failure in patients who had not been recommended valve replacement. The median age of the study population (n = 101) was 75 years (interquartile range 65 to 79 years), and 67% were judged questionably symptomatic. During a follow-up at 24 ± 6 months, the rate of unexpected cardiac death and unexpected hospitalization with heart failure was 0% and 6.0%, respectively. All-cause mortality was 4.0% compared with 8.0% in the age- and gender-matched population. For group 1, 26 of 70 (37.1%) succumbed to cardiac death, or were hospitalized because of heart failure, or underwent valve replacement, and for group 2 this was 12 of 31 (38.7%). In conclusion, if CPET does not indicate a significant hemodynamic compromise because of aortic stenosis, an initially conservative strategy results in a good prognosis and an acceptable event rate.

The Physiological Burden of the 6-Minute Walk Test Compared With Cardiopulmonary Exercise Stress Test in Patients With Severe Aortic Stenosis

“…Maximal exercise tests are generally restricted to asymptomatic AS patients since maximal effort in truly symptomatic patients with AS is considered an absolute contraindication 1,2 . Strict "contraindication" to exercise testing becomes ambiguous in patients who are sedentary since pertinent symptoms may only become apparent during exercise provocation 1 as one-third of patients claiming to be asymptomatic may develop symptoms during exercise [3][4][5][6] . Given such a fine line between being symptomatic vs. asymptomatic, it is important to emphasize that a meta-analysis concluded that symptom-limited stress testing is safe and has an important prognostic value in patients with severe AS 7 .…”

Improved Exercise Tolerance, Oxygen Delivery, and Oxygen Utilization After Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis

“…In the early seventies, Lee et al reported similar systemic hemodynamic improvements with reduced ventricular preload that closely matched the exercise-induced increase in oxygen consumption in 12 patients, 3 to 6 months following surgical aortic valve replacement. 11 As a maximal cardiopulmonary exercise test was deemed inappropriate and potentially dangerous in elderly patients with severe symptomatic AS, 12 we performed a submaximal bicycle exercise test that was safely conducted in all patients. As it integrates cardiopulmonary and musculoskeletal systems functioning, this test appears suitable for baseline screening, follow-up assessment, and research purposes, particularly among frail subjects.…”

Non-Invasive Cardiac Output Measurement Using Inert Gas Rebreathing Method during Cardiopulmonary Exercise Testing—A Systematic Review

“…The researchers conducting the studies included in this systematic review conducted CPET-IGR using varied testing protocols. Most of these were tests involving a progressive work rate [31,[59][60][61]63,[65][66][67][68][69][70][72][73][74][75][76][77][78][79][80]82,83,85,[93][94][95][96][97][98]101,102], while a few studies used constant load protocols in addition to progressive work rate tests [71,81,92,99,100].…”

“…Firstly, some of the studies included in this review were based on small patient groups [31,51,59,66,76,79], and most of the studies focused on patients with either healthy conditions or heart failure. There were few studies available that focused on other disease entities [85,89,[95][96][97][98][99]. Additionally, not all the required values could be obtained from the studies because they were not described.…”