Epidemiological studies reveal that cardiovascular disease is a leading cause of death around the world. Specifically, the prevalence of ST-segment elevation myocardial infarction (STEMI) has steadily increased in recent years.

Acute coronary syndrome (ACS), which encompasses STEMI, is one of the potential complications of sickle cell disease. It is often fatal.

Cardiovascular disease represents a huge burden of care among low-income and middle-income nations. This is because many lack sufficient healthcare infrastructure to adequately care for patients with cardiovascular disease. Countries that lack the manpower and the facilities to cope inadvertently have poorer patient outcomes. 

Sickle Cell Disease and the Heart 

Patients who have been diagnosed with both sickle cell disease and cardiovascular disease are at a higher risk of clinical deterioration. Patients with sickle cell disease often contend with painful vaso-occlusive crises. Vaso-occlusive crises can cause vaso-occlusion in the microvasculature, triggering a vicious cycle of ischemia and repercussion. The result is widespread vasculopathy and multi-organ damage, including the heart. 

These swings between tissue ischemia and infarction are a hallmark of sickle cell disease. Pain is often the result. This chronic inflammatory state and vasculopathy lead naturally to end-organ damage. 

Read more about sickle cell disease etiology

“In an autopsy study of 306 [sickle cell disease] patients, cardiac involvement was common with cardiomegaly seen in 58%, myocardial micro-infarcts in 20%, and heart failure in 10%,” Sachdev and colleagues wrote in Trends in Cardiovascular Medicine. 

Why is the heart so vulnerable to sickle cell disease pathology? Two factors play an outsized role: anemia and the effects of HbS polymerization. The decreasing capacity of the blood to carry oxygen results in an abnormally large stroke volume; this activates the renin-angiotensin-aldosterone system to retain salt and water, causing fluid overload. Fluid overload eventually dilates the cardiac chambers, increasing the stress on the cardiac walls. Eventually, heart failure occurs. 

Detecting STEMI in Sickle Cell Disease 

It is clear that the pathologies associated with sickle cell disease involve multiple organs, especially the heart. In patients with STEMI, there are a few physical telltale signs that ACS has taken place. Among them are tachycardia, hypotension, pulmonary edema, narrow pulse pressure, and inadequate perfusion. 

Certain biomarkers are useful when STEMI is suspected. For example, CK-MB is immensely useful in diagnosing STEMI. The ever-useful electrocardiogram (ECG) machine should be used to conduct an immediate ECG evaluation, which will aid diagnosis. 

“For patients who manifest ST-segment elevation diagnostic for STEMI, emergent reperfusion therapy remains the immediate priority,” Bergmark and colleagues wrote in Lancet. “The latest data continue to reinforce the association between prompt (<90 min) reperfusion and more favorable long-term clinical outcomes.”

A Variety of Treatment Strategies

Percutaneous coronary intervention should be attempted if the time to procedure is expected to be 120 minutes or less. If this is not possible, fibrinolysis should be administered, followed by invasive angiography within the next 24 hours, Bergmark et al wrote.

In the case of a patient with sickle cell disease, patients should be administered packed red blood cell transfusions. This is to increase the concentration of HbA and lower the concentration of HbS. This allows oxygen delivery to proceed and prevents further sickling and vaso-occlusion. 

In hypoxemic patients, it is vital that respiratory support is given. Noninvasive mechanical ventilation may potentially reduce the need for intubation or mechanical ventilation. Noninvasive mechanical ventilation can improve oxygenation, reduce the burden of breathing, and increase mean airway pressure. 

In addition, pain control is important in managing patients with ACS. Nonsteroidal anti-inflammatory drugs (NSAIDs) can be useful in decreasing pain and inflammation. In some cases, opioids are used as analgesia, but they must be closely monitored to prevent respiratory depression and atelectasis. 

Read more about sickle cell disease treatment 

Although fluid overload is a feature of congestive heart disease, patients with ACS are often too sick to maintain proper hydration. Hence, physicians can consider starting the patient on intravenous crystalloid infusion, with care to avoid overhydration. 

The typically prescribed treatment for ACS remains dual antiplatelet therapy. This is sometimes accompanied by prasugrel or ticagrelor in addition to low-dose aspirin. 

In many ways, the acute treatment of a patient with sickle cell disease who experiences ACS is to be treated like any acute patient who presents with ACS in an emergency setting. The key difference is that patients with sickle cell disease often have multiple comorbidities and are generally more vulnerable to severe disease compared to the general population. 

In addition, in some cases of sickle cell disease, considerable heart damage may already be present. The most important goal to achieve in an ACS setting is to save the patient’s life; once the moment of danger has passed, it is important that the attending physician understands the state of the patient’s sickle cell disease in order to better make decisions that improve quality of life. 

References

Sachdev V, Rosing DR, Thein SL. Cardiovascular complications of sickle cell diseaseTrends Cardiovasc Med. 2021;31(3):187-193. doi:10.1016/j.tcm.2020.02.002

Farooq S, Abu Omar M, Salzman GA. Acute chest syndrome in sickle cell diseaseHosp Pract (1995). 2018;46(3):144-151. doi:10.1080/21548331.2018.1464363

Koehl JL, Koyfman A, Hayes BD, Long B. High risk and low prevalence diseases: acute chest syndrome in sickle cell diseaseAm J Emerg Med. 2022;58:235-244. doi:10.1016/j.ajem.2022.06.018