13: Multiple Conditions - Case 2: Mina
Mina's multiple conditions
Like Sandy, Mina has a number of health conditions which impact on her heart failure. Again, these include both cardiac and non-cardiac conditions.
Aortic stenosis is a narrowing of the aortic valve opening in the heart. It becomes increasingly common with age, as the calcium deposits and scarring which occur with age damage the valve and restrict the amount of blood flowing through it. The left ventricle of the heart has to work harder to pump blood through the narrowed valve into the aorta, causing the wall of the ventricle to thicken. This thickened ventricular wall takes up more space, leaving less room to accommodate the amount of blood required to supply the body and, eventually, leading to heart failure. As the number of elderly people in the population increases, so too does the prevalence of aortic stenosis as a cause of heart failure.
Left Ventricular Systolic Dysfunction
Mina has a moderate degree of left ventricle systolic dysfuncion (LVSD), probably caused by her aortic stenosis. LVSD is where decreased contractility of the heart leads to a decrease in cardiac output. The left ventricle becomes enlarged and dilated, meaning that it is less able to contract strongly enough to pump blood out and around the body. The end result is sodium retention and fluid overload.
Mitral Valve Regurgitation
Mitral valve regurgitation (also known as incompetence) occurs when the mitral valve does not close properly. When the valve does not seal effectively, this allows blood to flow in two directions during contractions. Some blood flows through into the ventricle and some flows back into the left atrium. Increased blood volume and pressure in the left atrium can cause increased pressure in the pulmonary veins and cause pulmonary congestion. If the regurgitation is severe, it can cause the heart to enlarge in an effort to maintain forward flow of the blood, resulting in heart failure.
Pulmonary congestion leads to low oxygen levels in the alveoli of the lungs. This causes the pulmonary arteries to constrict, increasing the pressure within the vessels. If the pressure in the pulmonary arteries rises to a sufficiently high level, the result is secondary pulmonary hypertension. The right side of the heart has to work harder to push blood through the pulmonary arteries into the lungs. Over time, the right ventricle becomes thickened and enlarged, leading to a deterioration in the heart's pumping mechanism and resulting in heart failure.
Chronic Obstructive Airways Disease
Chronic Obstructive Airways Disease (COPD) is characterised by persistent respiratory symptoms and airflow limitations. These are normally due to abnormalities in the airway or the alveoli, usually caused by significant exposure to noxious particles or gases, such as those found in cigarette smoke. (Although Mina does not smoke now, she was a heavy smoker for many years.) COPD is irreversible and progressive, causing many of the same symptoms as heart failure. It is a common comorbidity with heart failure and, like heart failure, the risk of developing COPD increases with age. A survey of primary care patients in Scotland found that 23.8% of patients with heart failure also had COPD (Hawkins et al, 2010). It appears that COPD patients are at higher risk of developing heart failure and other cardiovascular conditions due to a shared pathogenic mechanism, associated with low-grade systemic inflammation.
There are known major links between cardiac disease and depression. Mina has suffered from severe depression in the past and such depression is now known to be a risk factor for cardiac disease. Depression has been associated with a four fold increase in the risk of heart disease, even when other risk factors, such as smoking, are controlled. The links between the two are bidirectional, with the impact of heart failure and the lifestyle changes it involves, frequently leading to a person becoming depressed.
In Mina's case, the presence of other conditions in addition to her heart failure makes diagnosis and treatment more difficult and complex, as her multiple conditions share many of the same signs and symptoms. The existence of multiple conditions presents challenges for management, particularly in relation to drug therapy.