Methods

The study population included all patients who had undergone transthoracic echocardiography during 2007 and met the echocardiographic criteria for severe AS, including an aortic valve area <1.0 cm ² and a mean aortic valve gradient of ≥40 mm Hg and/or an aortic jet velocity of ≥4 m/s, according to the American College of Cardiology, American Heart Association, and the American Society of Echocardiography guidelines.

The medical records were initially reviewed, and data were collected specifically for age, gender, height, weight, and the presence of co-morbidities, including hypertension, diabetes, chronic lung disease, chronic kidney disease, congestive heart failure, coronary artery disease, history of coronary revascularization, previous AVR, and active cancer of any kind. The test results for exercise stress testing were collected when performed. The clinic notes were reviewed for the presence of symptoms, including chest pain, dyspnea, heart failure, dizziness, and syncope. Documentation was noted of whether the physician attributed the symptoms to AS. A referral to surgery and the subsequent date of AVR was also recorded. The operative risk was calculated using the on-line Society of Thoracic Surgeons (STS) Risk Calculator and logistic EuroSCORE, which are validated risk assessment tools. In addition, the reasons a patient was not referred to a cardiothoracic surgeon were included.

The medical records were then repeatedly reviewed every month for >1 year for the occurrence of symptoms, symptom progression, AVR, and death. Death was confirmed by the Social Security Death index. The cause of death was collected whenever possible. The institutional review board approved the study protocol.

Results

A total of 11,000 transthoracic echocardiograms were performed in 2007. Of the patients who underwent transthoracic echocardiography, 106 met the prespecified criteria for severe AS and were included in the present study. Of the 106 patients with severe AS, 33 (31%) underwent AVR and 73 (69%) did not ( Table 1 ). Of the types of physicians taking care of these patients, cardiologists were the most likely not to refer patients with severe AS for AVR (47; 64%), followed by generalists (16; 22%) and vascular surgeons (2; 3%). The specialties of 8 physicians (11%) were unknown. All patients who were evaluated by cardiothoracic surgeons underwent AVR.

Symptoms such as chest pain, dizziness, syncope, dyspnea, and heart failure were prevalent in both the patients who underwent surgery and those who did not. Of the patients who underwent AVR, 94% were symptomatic. Of the patients who were not referred for surgery, 31 (42%) were symptomatic ( Figure 1 ). For the symptomatic patients, the most common reason for not performing AVR was that the physician caring for the patient did not attribute the patient’s symptoms to AS (9 patients; 29%). A high operative risk was the reason 5 patients (15%) were not referred for AVR, although the calculated STS risk and EuroSCORE was high in only 3 of the patients (10%). The remaining reasons included patient refusal (5 patients; 15%), AS not considered truly severe (3 patients; 11%), limited life expectancy (3 patients; 11%), advanced age (2 patients; 6%), patient transferred to another hospital (1 patient; 3%), symptoms not recognized by the physician (2 patients; 6%), and pseudo-AS (1 patient; 3%; Figure 2 ).

Number of patients with symptomatic or asymptomatic, severe AS referred to cardiothoracic surgery for AVR.

Physicians’ reasons for not performing ARV in symptomatic patients.

For the patients who were thought to be asymptomatic and accordingly were not referred for AVR, the most common reason for not undergoing AVR was the lack of symptoms (29 patients; 70%), followed by the presence of co-morbidities (3; 7%), AS not considered truly severe (2 patients; 4%), and high operative risk (1 patient; 2%; Figure 3 ). The calculated STS risk and EuroSCORE for the patients assumed to be at high operative risk was low to moderate and resulted from age only. Seven of the reasons (17%) were not specified. Only 2 (4%) of these patients had undergone exercise stress testing to determine whether the patient was objectively symptomatic. These tests were positive, and the patients underwent successful surgery.

Physicians’ reasons for not performing AVR in asymptomatic patients.

Of the 106 patients, 21 (20%) have died since their echocardiographic study. Of these 21 patients, 6 (6%) had undergone AVR and 15 (14%) had not. Of the 6 patients who had undergone AVR, 3 had died from bacteremia within 2 months of surgery. Of the 15 patients who had not undergone AVR, 10 were symptomatic and 5 were thought to be asymptomatic. Since the initial data collection, 7 more patients had undergone AVR. Of these 7 patients, 3 were symptomatic and were not initially referred for surgery because 1 was considered at high operative risk, 1 had symptoms not attributed to AS, and 1 was thought not to be truly symptomatic. The remaining patients were considered asymptomatic. All patients were alive and well at their last follow-up visit.