Procalcitonin and Heart Attack

Introduction
Heart disease is essentially one of the significant causes of death in many countries, including India. A sedimentary and unhealthy shift in the lifestyle provokes such conditions. Health issues related to the heart, if left undiagnosed and not treated in time, then it could even be life-threatening. Many pathological tools have been determined to detect a particular heart condition to save a being from facing the worst. Troponin T, Troponin I, Lipid profile, Phosphokinase, Creatinine, and Myoglobin, are the various blood tests that could help a practitioner diagnose if a person has some abnormalities associated with the heart.

Can procalcitonin too contribute towards the diagnosis of a heart attack? Please keep reading to know it better.

Let us first understand what exactly procalcitonin is?
It is a peptide precursor of the hormone calcitonin that maintains the blood’s optimal calcium and phosphorus levels. In an average individual, the levels of procalcitonin in the blood are expected to be minimal as most of this precursor would soon convert into calcitonin. Therefore, biologically there is no appropriate use of procalcitonin to the human body; however, it could stand as a potential diagnostic marker.

Uses of procalcitonin as a diagnostic marker

Over the years, procalcitonin has evolved as an excellent diagnostic marker that could help make differential diagnoses between the infectious and the noninfectious inflammatory responses of the body. Also, it’s a fine line that differentiates between viral infection and bacterial infection.

This 116 amino acid precursor of calcitonin is amplified when the body is under some inflammatory condition. During inflammation, numerous metabolites are released on the active site that elevates procalcitonin levels in the blood. In addition, inflammation caused by a bacterial origin could be directly related to the high procalcitonin levels. For example, studies have found that patients suffering from sepsis, bacterial meningitis, and septic shocks featured high procalcitonin levels in the blood. This signifies that procalcitonin is a better diagnostic marker for detecting bacterial infections as the specificity is higher when compared with CRP (C- Reactive Protein) or other immunological indices.
Also, there have been queries related to procalcitonin’s connection with heart diseases. Well, first, we must analyze the below points.

What exactly happens during a heart attack?

Due to the fat built up, excess cholesterol, and other substances accumulating at a spot in the artery, plaque is created. This plaque, in turn, breaks into blood clots, restricting the supply of oxygen-rich blood to the heart. The heart muscles starve for oxygen and nutrients in this condition, resulting in a heart attack. So, a cardiac arrest or heart attack is nothing but an injury to the tissues of the heart.

This injury initiates the release of several systemic components as an immune response. For example, CRP or C- Reactive Protein, WBCs (White Blood Cells), and other heart biomarkers surge into the bloodstream, indicating a severe trauma to the myocardial tissues.

Connection of procalcitonin with heart diseases

A study supported by the Australian Society of Cardiology was conducted to determine the relationship of high procalcitonin levels with acute STEMI (ST-Elevation Myocardial Infarction) accompanied by a bacterial infection. Also, many other studies have been conducted to understand the connection of Procalcitonin with heart diseases. Below mentioned are some valid causes explaining why blood procalcitonin levels could increase during a heart disease?

• Patients under emergency medicine suffer from severe health conditions such as acute heart failure. Most of the time, patients admitted to the emergency department suffer from more than one disease, worsening their state of health. Thus, any other inflammatory disease accompanying the heart could stand as one of the reasons why there is a noticeable elevation in the levels of procalcitonin.
• Dyspnea is a symptom rather than a disease seen in health adversities such as acute heart failure, respiratory disorders, and other diseases. It is a medical condition where the patient struggles to breathe. Dyspnea is probably one of the primary reasons for the mortality of the patients admitted to the emergency department. However, it has been found that there was an increase in procalcitonin levels in patients suffering from dyspnea.
• An article mentioned in the John Wiley & Sons Ltd suggests a close relation of worst phase heart failure with the systemic inflammatory conditions. This implies that patients with severe heart disease feature inflammation, activating the metabolites such as endotoxins and cytokines that generate more production of procalcitonin. In addition, it has been investigated that there was a marked rise in the levels of procalcitonin in the bloodstream during the edematous state of acute heart failure.
• As per one hypothesis stated in the National Library of Medicine literature, mesenteric congestion during acute heart failure could be a potential cause of increased procalcitonin levels. For example, the bacteria residing in the intestine could translocate into the bloodstream, resulting in endotoxemia, i.e., a kind of immune activation that could boost procalcitonin.
• An apparent reason why procalcitonin levels suddenly spike is the bacterial infection. Researchers have observed that patients suffering from acute heart failure with concomitant bacterial infection showed a significant rise in the blood procalcitonin levels.

Uses of procalcitonin during heart diseases

Procalcitonin might not stay sufficient while diagnosing heart disease, but it could suggest the treatments before it takes a fatal turn. Have a look at the ways procalcitonin could help:

• Suggesting concomitant bacterial infection
  Patients in the critical care or emergency department often have an infection associated with heart disease. However, when procalcitonin levels are higher during acute heart failure, it could indicate the possibility that the patient has a bacterial infection. This, in a way, helps at curbing the nasty side of the heart disease aggravated by the underlying bacterial infection.
• Assisting in antibiotic therapy
  Continual monitoring of the procalcitonin levels during the concomitant bacterial infection of the acute heart failure could help decide the antibiotic therapy and alter the doses (if required). For example, one study reveals that patients in the emergency department showed a significant reduction in the procalcitonin levels of the blood when administered with antibiotics.

Closing Remarks
There is no doubt that procalcitonin is an excellent biomarker to help diagnose the presence and progression of a bacterial infection. Unfortunately, despite numerous studies establishing the relation between high procalcitonin and heart attack, no precise data infers procalcitonin as a cardiac marker. However, this peptide precursor of calcitonin guides an appropriate antibiotic therapy during the concomitant bacterial infection with acute heart failure.

References:

1. Banach J, Wołowiec Ł, Rogowicz D, Gackowska L, Kubiszewska I, Gilewski W, et al. Procalcitonin (PCT) predicts worse outcome in patients with chronic heart failure with reduced ejection fraction (HFrEF). Dis Markers [Internet]. 2018 [cited 2022 Feb 10];2018:9542784. Available from: https://www.hindawi.com/journals/dm/2018/9542784/
2. Wang W, Zhang X, Ge N, Liu J, Yuan H, Zhang P, et al. Procalcitonin testing for diagnosis and short-term prognosis in bacterial infection complicated by congestive heart failure: a multicenter analysis of 4,698 cases. Crit Care [Internet]. 2014;18(1):R4. Available from: http://dx.doi.org/10.1186/cc13181
3. Reindl M, Tiller C, Holzknecht M, Lechner I, Henninger B, Mayr A, et al. Association of myocardial injury with serum procalcitonin levels in patients with ST-elevation myocardial infarction. JAMA Netw Open [Internet]. 2020 [cited 2022 Feb 10];3(6):e207030. Available from: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2767137
4. Heart attack [Internet]. Mayo Clinic. [cited 2022 Feb 10]. Available from: https://www.mayoclinic.org/diseases-conditions/heart-attack/symptoms-causes/syc-20373106
5. Möckel M, Searle J, Maisel A. The role of procalcitonin in acute heart failure patients. ESC Heart Fail [Internet]. 2017;4(3):203–8. Available from: http://dx.doi.org/10.1002/ehf2.12189