As we approach Valentine’s Day for another year, thoughts understandably turn to overcrowded restaurants, last-minute gifts, and extravagant shows of affection. However, when it comes to important matters of the heart, we might do better to pay closer attention each year to September 29th, also known as World Heart Day.
Launched in 2000 by the World Heart Foundation (WHF), World Heart Day is designed to raise awareness of the dangers of cardiovascular disease (CVD), the leading cause of death globally (accounting for around a third of all deaths). CVD claims over 18 million lives a year, with one third of these deaths occurring in people under 70 years of age.
What is cardiovascular disease?
CVDs are a group of disorders of the heart and blood vessels, and include coronary heart disease (e.g. heart attacks) and cerebrovascular diseases (e.g. strokes), which account for around 85% of all CVD deaths. Many of these are related to lifestyle factors such as smoking, an unhealthy diet or high blood pressure, with the WHF estimating that as many as 80% of all CVD deaths are avoidable.
However, the heart can also become weakened by pre-existing heart conditions or in some cases, with the deterioration in heart function due to age. Of these age-related conditions, one of the most prevalent is aortic stenosis (AS).
What is AS?
AS is a condition where calcium builds up in the aortic valve. As a healthy heart contracts, freshly oxygenated blood is pumped out of the left ventricle through the aortic valve, into the aorta and out into the body (see image to left). However, in a patient with AS, a build-up of calcium narrows the aortic valve, restricting blood flow into the aorta. This causes the heart to work harder to generate blood flow around the body, and eventually it can lead to heart failure. Patients with AS are typically symptomless for several years, but once heart failure symptoms appear, life expectancy can be as little as two years if left untreated.
Andrew Duncan
Senior Equity Analyst
Severe AS is the most common reason for heart valve surgery in developed countries. However, due to its largely asymptomatic nature, diagnosis rates are low. Furthermore, even if a diagnosis is made, for several reasons treatment has remained stubbornly low. Put together, today it is estimated that overall treatment rates for patients with moderate or severe AS is around 15% (in the US). This percentage is lower worldwide.
AS is predominantly a disease of ageing, affecting as many as one in eight people over 75 globally. With the United Nations estimating that the number of people over 65 will more than double between 2019 and 2050, from c.700 million to c.1.5 billion, AS cases could create a significant burden on healthcare budgets and societies over the coming decades.
What are the treatment options?
Initially, surgeons had to reopen narrow aortic valves using a scalpel. This was followed by the introduction of artificial valves in the 1960s that delivered vastly superior outcomes. Importantly, both procedures required open heart surgery, which requires a lengthy hospital stay and recovery times. More recently, however, minimally invasive replacement aortic valves (known as TAVR) have been introduced. These valves are carried via a catheter placed in a small incision in the leg or chest, travelling inside the body to the heart, where the valve is expanded via balloon inside the existing valve with no need for open heart surgery. Patients treated with TAVR today face much shorter hospital stays and recovery periods, which is better for the patient and the payer – a recent study showed that TAVR procedures saved between $10k and $29k per patient compared to surgical aortic valve replacement (SAVR).