India, Nov. 4 -- In many Indian households, caregiving begins long before anyone calls it that. A daughter notices that her father no longer walks to buy milk. A spouse sees him stop midway up the stairs. A son living in another city hears the same response during their regular calls: "Tired today." Individually, these moments may seem insignificant. Over time, however, they can point to a gradual change in everyday life.

The heart has four valves that regulate blood flow. When a valve narrows or does not close properly, the heart has to work harder. Aortic stenosis, which becomes more common with age, occurs when the valve through which blood leaves the heart narrows.

Instead of describing a loved one as simply becoming slower, familie...