Alpha-1 antitrypsin deficiency, COPD and the heart – comorbidities in COPD

Lecture by Prof. Dr. Peter Alter on the occasion of the Alpha1 Information Day 2017

Almost every person with chronic obstructive pulmonary disease (COPD) also has a co-existing condition affecting another organ system. Doctors refer to these as comorbidities. In COPD, co-existing conditions affecting the heart and blood vessels or other risk factors are particularly common. A Dutch study showed that more than half of COPD patients have atherosclerosis or high blood pressure. Approximately 9% of patients suffered a heart attack. Other common co-existing conditions included disorders of glucose metabolism (54%, diabetes) or lipid metabolism with elevated cholesterol levels (36%). At least 98% of COPD patients had at least one co-existing condition, and more than half had four or more different co-existing conditions.

Heart disease in COPD

Heart disease is associated with reduced life expectancy in people with COPD. This was the finding of a study from Copenhagen: More than 16,000 people over the age of 40 from the general population were followed for 35 years. During this period, 11,000 deaths occurred; COPD patients had a significantly lower life expectancy than people without COPD. Life expectancy decreased with increasing severity of the lung disease, expressed by the so-called GOLD stage (I to IV). Importantly, heart rate was also associated with life expectancy: the higher the resting rate, the lower the life expectancy. For example, comparing heart rates above 85 beats per minute with rates below 65 beats per minute revealed a difference in life expectancy of up to almost 10 years, and this difference depended on the GOLD stage of COPD (I-IV). This does not mean that a faster heartbeat in itself is the cause of a shorter life expectancy; it can also be an expression of other changes that themselves constitute the actual cause.

”Cigarette smoking promotes both the development and worsening of COPD, and the development and worsening of cardiovascular diseases.

COPD increases the risk of heart attack

Having COPD increases the risk of hospitalization due to a heart attack or stroke. This was the finding of an analysis of 1.2 million medical records from the United Kingdom. Within three years, individuals with COPD had a ten times higher risk of a heart attack and a three times higher risk of a stroke. However, it's important to consider that these conditions can also be caused by shared risk factors without being directly related. A key example is cigarette smoking, which not only promotes the development and worsening of COPD but also the development and worsening of cardiovascular diseases. Approximately one-third of all patients with COPD also have cardiovascular disease. Conversely, about one-third of all patients with cardiovascular disease have lung disease. There is therefore a significant overlap between the two areas.

COPD and heart failure

English researchers also investigated the influence of COPD on heart failure. Nearly 10,000 patients admitted to the hospital with acute heart failure were followed up for up to ten years. Of these, roughly a third also had COPD. The study revealed that many people with COPD had not been prescribed the necessary heart medications. One reason for this could be the long-standing concern about prescribing beta-blockers, which are important for heart health, to COPD patients, based on the assumption that they could cause bronchoconstriction. However, this concern is unfounded, and beta-blockers are also beneficial for patients with COPD. In the study, patients also took other heart medications less frequently, particularly ACE inhibitors or angiotensin II receptor blockers. The researchers then examined how many patients were still alive after one and five years. The results showed that individuals with heart failure but without COPD lived longer than those with additional COPD. The severity of the COPD also played a role. Five years after acute heart failure, a larger proportion of patients with mild COPD were still alive than those with severe COPD. The lung function test FEV1 (the maximum volume achievable in the first second of a forceful exhalation) proved to be a very informative indicator of the disease progression.

”New imaging techniques allow researchers to directly visualize how the heart and lungs work together.

Magnetresonanztomografie (MRT) des Brustkorbs

Influence of the lungs on heart function

New imaging techniques allow researchers to directly visualize how the heart and lungs work together. They use a special magnetic resonance imaging (MRI) scan of the chest, combined with complex computer calculations. The examination is time-consuming and takes about 20-30 minutes. In patients with COPD, various changes in the heart have been observed using MRI. The right ventricle, which pumps blood to the lungs, was bulging in some patients. This can be explained by the fact that the pressure in the right ventricle was increased due to the narrowed pulmonary vessels, causing the heart muscle to bulge outwards. Other individuals showed a thickened muscle wall of the right ventricle.

During breathing, the pressure conditions in the chest cavity change significantly. In healthy individuals, the diaphragm has the shape of a double dome, which moves downwards during inhalation and upwards during exhalation. Patients with pulmonary emphysema exhibit what is known as lung hyperinflation because they have difficulty exhaling the inhaled air. This enlarged lung is accompanied by a flattened and low-lying diaphragm, whose mobility is significantly restricted. When one takes particularly deep breaths, increased pressures arise in the chest cavity, which are apparently also transmitted to the heart and blood vessels. In patients with COPD, these pressure conditions are altered. Here, the narrowed airways and their increased resistance, the hyperinflation of the lungs, and the relatively immobile diaphragm all play a role. As a result, the tension in the heart muscle wall increases.

COSYCONET research network

As part of the COSYCONET study, which included 2741 patients, data on cardiac function are also collected regularly. Echocardiograms from visit 1 are available for approximately 2400 patients. The next ultrasound examination was performed at visit 3, approximately 18 months later. Even during this short period, minor changes were already visible. The muscle mass of the left ventricle decreased slightly. At the same time, the size of the left ventricle and the wall tension increased slightly. These changes suggest that the ventricle will continue to change over time. To investigate this further, another echocardiogram was performed at visit 4. One of the reasons why patients with COPD are more likely to develop heart disease could be the increased wall tension of the left ventricle. This tension is higher the worse the lung function. This not only has a mechanical effect but also influences the electrical processes in the heart that regulate its beat. Normally, each heart muscle cell is electrically excited via a specific conduction system. When muscles are stretched more than normal, this changes the cells' ability to respond, and this can cause cardiac arrhythmias.

During upcoming visits of the COSYCONET study, cardiac findings will also be collected using echocardiography (ECG) and electrocardiogram (ECG). The researchers hope to gain new insights into the interaction between COPD and cardiac function, which are important for treatment and monitoring the course of the disease.