Untreated aortic stenosis is deadly, here’s what GPs need to know.
“Fifty percent of people with untreated aortic stenosis will die within two years of getting symptoms.”
So says Sydney cardiologist, Professor Andrew Sindone, who points out this is a significantly worse prognosis than most cancers.
And before you start thinking aortic stenosis is a rare valvular condition, on a recent Healthed podcast, Professor Sindone also explains that research suggests as many as one in eight Australians over the age of 75 has aortic stenosis.
Of course, not all these people will have a stenosis severe enough to cause symptoms. But Professor Sindone says symptoms are often non-specific and can develop insidiously, so people may be symptomatic and not even realise it. Often, common symptoms such as shortness of breath or feeling faint on exertion or fatigue are not initially attributed to a valvular issue.
Diagnosing aortic stenosis
That’s why it’s important to think of and look for the condition in order to diagnose it. As Professor Sindone says – “suspect, listen and refer.”
In most people, the characteristic systolic murmur of aortic stenosis is quite apparent on auscultation. Given the prevalence of aortic stenosis, Professor Sindone recommends GPs routinely listen to patients’ hearts, especially in older patients.
And while there are a few indices that might help determine how severe the stenosis is – such as the presence of a thrill, a fourth heart sound or a narrow pulse pressure –- the reality is, the patient needs to be referred regardless of these indices—either for an echocardiograph and then a cardiologist or directly to a cardiologist.
Echocardiography is still the ‘gold standard’ investigation to diagnose aortic stenosis, and indeed any valvular disorder. It can detect anatomical abnormalities as well assess any functional deficit.
As for the treatment of aortic stenosis, Professor Sindone says this is where ‘there has been a huge revolution in the last eight to 10 years.’
TAVI: ‘Life-changing’ procedure
TAVI or transcutaneous aortic valve implantation is rapidly superseding the traditional surgical aortic valve replacement, which is a far more invasive and risky operation only available to those people who are well enough to withstand such a major surgery.
The TAVI involves the insertion of a catheter into the femoral artery and feeding it through the vascular system to the aortic valve. The artificial valve is then expanded via the catheter over the previously dysfunctional valve, expanding the aperture and implanting the new device.
Many more people can access definitive treatment now
The TAVI is relatively non-invasive (compared to having to have a chest ‘cracked open’), takes only about an hour or less to do and has an instant effect and rapid recovery time. This has meant many more patients with aortic stenosis can now access definitive treatment.
Improved outcomes and fewer complications
Professor Sindone said the original studies were done on patients who were deemed not suitable for open heart surgery. Researchers found significant improvements in survival rates among those who had a TAVI compared to people who did not have surgery. They then looked at people who were eligible for surgical aortic valve replacement but were high risk. The studies showed that the high-risk patients who had a TAVI did much better in terms of health outcomes and fewer complications that those people who underwent the open heart surgery. There is now increasing evidence that TAVI is an effective and safer option for people considered at just moderate risk of surgery.
But unlike in a surgical aortic valve replacement, the valve inserted in a TAVI procedure is not metal and is not guaranteed to last as long as a metal valve. Therefore, it may not be the best option for patients aged under55.
Fortunately, these days, most patients diagnosed with aortic stenosis will be referred to a ‘heart team’ which will generally consist of a cardiac surgeon, an interventional cardiologist and a geriatrician, who will advise the patient on the best option for treatment.
Access issues
While the TAVI procedure is described as a ‘game-changer’ by Professor Sindone, there are still some issues with access access, particularly for those in the public system. The government has placed limitations on the number of procedures that can be done by a centre, and, as yet, not all hospitals have the TAVI-option available.
Risks to be aware of with TAVI
In addition, Professor Sindone said it was also important to note the relatively high risk of developing an arrhythmia after a TAVI.
With any cardiac surgery there is a 30% risk of developing atrial fibrillation, and after valvular surgery this rises to 50%, however this is usually temporary.
Because of the proximity of the artificial valve to the A-V node, there is also a significant risk of complete heart block.
Evidence to date shows that about one third of patients undergoing a TAVI will need a pacemaker, and patients always need to be made aware of this risk.
Other consequences include the ongoing need to have endocarditis prophylaxis for future at-risk procedures such as dental surgery.
Anticoagulants need to be taken post-procedure, but generally only for a period of one to three months. After that, the recommendation is simply ongoing low-dose aspirin.
As Professor Sindone says, it is now more important than ever that aortic stenosis is recognised and diagnosed as we are now aware of the significant morbidity and mortality associated with the condition if left untreated, and we now can often offer patients this ‘nothing-short-of revolutionary treatment’.
