Why Do Cardiologists Fail to Follow the Surgical Guidelines for Severe Aortic Stenosis?

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Abstract

Many patients with symptomatic severe aortic stenosis (AS) do not receive aortic valve replacement (AVR) even though the American College of Cardiology/American Heart Association/American Society of Echocardiography guidelines give a class I indication for this type of management. We determined the proportion of patients with severe AS who did not undergo AVR in a university hospital setting and identified the reasons for lack of surgical referrals despite the presence of a class I guideline indication. We studied consecutive patients with severe AS by echocardiographic criteria (aortic valve area <1.0 cm2, aortic valve gradient >40mmHg). Of the 106 patients with severe AS, 33 (31%) underwent AVR while 73 (69%) did not proceed to surgery. Of those patients without AVR, 31 (42%) were symptomatic. The most common reason patients with symptomatic severe AS did not receive AVR was that the symptoms were thought to be unrelated to AS. After 15 months, 15 patients (14%) who did not undergo AVR had died. In patients with severe AS, physicians commonly under-recognize symptoms and overestimate operative risk. As a result, many patients with a class I indication for AVR do not receive it.

Disclosure
The authors have no conflicts of interest to declare.
Correspondence
Roberto M Lang, MD, University of Chicago Medical Center, 5084-5841 S Maryland Ave, Chicago, IL 60637. E: rlang@bsd.uchicago.edu
Received date
02 July 2010
Accepted date
16 July 2010
Citation
US Cardiology - Volume 7 Issue 2;2010:7(2):42-45
Correspondence
Roberto M Lang, MD, University of Chicago Medical Center, 5084-5841 S Maryland Ave, Chicago, IL 60637. E: rlang@bsd.uchicago.edu

Pages

Aortic stenosis (AS) is the most common valvular disease in the western hemisphere. Currently, 4% of the North American population above 75 years of age has AS, and approximately 50% of patients with mild to moderate AS will progress to hemodynamically severe AS in their lifetime.1
The natural history of the disease, which is largely unchanged since its initial description by Braunwald and Ross in 1968, includes a ‘latent period’ in which progressing aortic valvular obstruction leads to myocardial pressure overload followed by an abrupt and precipitous decline in survival after the onset of symptoms is manifested.2 The classic symptoms include angina, syncope, and heart failure, which develop primarily from the inability of the cardiac output to meet peripheral demands. The severity of the valvular stenosis at which these symptoms occur varies from patient to patient.
Despite several trials examining medical therapy for these patients, the only proven and accepted therapy is surgical replacement of the aortic valve.3,4 The operative mortality rate for aortic valve replacement (AVR) is around 4%, with long-term survival of 80% at three years.5 Although the operative mortality rate is relatively low, the American College of Cardiology (ACC)/American Heart Association (AHA)/American Society of Echocardiography (ASE) guidelines provide a class I indication for AVR in patients with severe AS only after the onset of symptoms.6 This recommendation is based on observational studies that demonstrate that patients with severe AS who are truly asymptomatic have only a 1% risk for undergoing sudden death.7
In this study we sought to ascertain the reasons why patients with severe AS were not referred for AVR in a university hospital setting. The study population included all patients who received a transthoracic echocardiogram at the University of Chicago Medical Center during calendar year 2007 and who met echocardiographic criteria for severe AS. We followed the ACC/AHA/ASE criteria for classifying severe AS, including all patients with an aortic valve area <1.0cm2, an aortic valve gradient ≥40mmHg, and an aortic jet velocity ≥4m/s.

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