Aortic stenosis (AS) is a progressive heart condition where the aortic valve, the main outflow valve of the heart, becomes narrowed and stiff. This narrowing restricts the flow of oxygen-rich blood from the heart’s main pumping chamber, the left ventricle, into the aorta and the rest of the body. To compensate, the heart must work harder, which leads to thickening of the heart muscle over time. Life expectancy with AS is highly variable, depending on the disease stage, severity, and whether the patient receives appropriate treatment.
The Natural Course of Untreated Aortic Stenosis
Aortic stenosis can remain asymptomatic for many years, but once the valve narrowing becomes severe and symptoms begin to appear, the prognosis without intervention rapidly deteriorates. The onset of symptoms is the traditional benchmark for estimating survival in untreated patients. Without valve replacement, the annual mortality rate for a person with severe AS is roughly 25%.
Life expectancy is directly tied to the specific symptom that first manifests. Patients who experience angina (chest pain) have an average survival of approximately three years without intervention. This chest pain signals that the heart muscle is not receiving enough blood supply to meet the increased demand from pumping against the narrowed valve.
Similarly, the onset of syncope (fainting episodes) also results in an average survival of about three years without treatment. Fainting often occurs during physical exertion because the heart cannot increase blood flow sufficiently to the brain. The most concerning symptom is the development of congestive heart failure, typically marked by shortness of breath or fatigue. Once heart failure symptoms appear, the average untreated survival time drops to 1.5 to 2 years. Intervention is strongly recommended immediately upon symptom development in severe cases due to this severe prognosis.
Assessing Severity and Individual Risk Factors
The severity of aortic stenosis is classified using imaging tests, primarily echocardiography, even before symptoms appear. Severe AS is defined by an Aortic Valve Area (AVA) of 1.0 square centimeter or less, and a Mean Gradient (MG)—the average pressure difference across the valve—of 40 millimeters of mercury (mmHg) or greater. The disease progresses through stages: “at-risk” (Stage A), progressive (Stage B), asymptomatic severe (Stage C), and finally, symptomatic severe disease (Stage D).
Individual patient risk factors significantly modify the overall outlook. Non-cardiac comorbidities, such as chronic kidney disease, coronary artery disease, and lung disease, negatively impact a patient’s prognosis. Advanced age is also a risk factor, as older patients naturally have a shorter life expectancy that must be factored into the survival estimate.
Furthermore, some patients present with “discordant grading,” where the AVA suggests severe disease but the pressure gradient is low. In these cases, physicians must use other tools, such as a CT scan to measure the aortic valve calcium score, to confirm the true severity and prognosis. Patients with these complex, low-flow patterns often have a worse prognosis than those with classic severe AS.
How Intervention Alters Life Expectancy
Aortic valve replacement (AVR), whether performed surgically (SAVR) or through a catheter-based procedure (TAVR), dramatically improves life expectancy. Successful treatment essentially removes the terminal prognosis associated with untreated severe AS. Survival then becomes dictated primarily by the patient’s age and co-existing medical conditions. Studies have shown that long-term survival following surgical AVR in elderly patients can be comparable to that of a matched general population for up to eight years post-procedure.
Specific data illustrates this improvement, with median survival times for patients undergoing SAVR varying significantly by age bracket:
- Patients aged 65 to 69 years have a median survival of approximately 15.1 years.
- Those aged 70 to 79 have a median survival of 10.6 years.
- Patients 80 years and older have a median survival of 6.3 years.
These figures demonstrate that successful intervention restores a significant number of life years compared to the untreated course. The long-term outlook is also influenced by the type of replacement valve chosen.
Mechanical Valves
Mechanical valves are known for their exceptional durability, often lasting the patient’s lifetime, but they require lifelong blood-thinning medication.
Bioprosthetic (Tissue) Valves
Bioprosthetic (tissue) valves, made from animal tissue, do not require continuous anticoagulation but have a limited lifespan, typically averaging around 15 years. Because tissue valves can deteriorate faster in younger patients, the need for a re-intervention later in life is a consideration for long-term life expectancy.