Pathophysiology: STEMI

Assessment One: Short answer questions on a case study

Length: 750 words

Weighting: 30%

Due: Week 5, Monday 22nd August 2022 at 12 midnight

Aim of the assessment

The purpose of this assessment is to enable you to:

1. Explain the underlying pathophysiology related to the clinical manifestations of ST elevation myocardial infarction (STEMI)
2. Discuss the importance of reperfusion in the management of a patient presenting with STEMI
3. Identify evidence-based strategies when caring for a patient presenting with STEMI

Case Study

Introduction:

• Mr Raj Kumar is a 64-year-old male with no known allergies (NKA)

Situation:

• Mr Raj Kumar arrived at the Emergency Department (ED) at 1130 hrs with central crushing chest pain radiating to his jaw since 1100 hrs.
• Findings from the 12 lead ECG recorded by paramedics showed ST elevation in leads V2, V3, V4.
• 300mg Aspirin administered en route to hospital.

Background:

• Hypertension (Captopril 12.5mg bd)
• Hyperlipidaemia (Simvastatin 40mg nocte).
• Type 2 Diabetes Mellitus (DM) (diet controlled)
• Weight 88kg

Assessment:

• Airway: Patent
• Breathing: Respiratory rate 18, bilateral air entry, breath sounds clear.  SpO₂ on room air 95%
• Circulation: Sinus Tachycardia 102bpm. BP 140/90. Diaphoretic and peripherally cool. Central crushing chest pain radiating to the jaw.

COLDSPA:

Character: crushing chest pain

Onset: 11am

Location: Central, radiating to jaw

Duration: ongoing

Severity: 7/10

Pattern: at rest, not relieved by SL Anginine Spray

Associated symptoms: diaphoresis

• Disability: Alert & oriented. Pupils equal and reacting to light (PEARL). Pain score 7/10. Equal strength in all four limbs.
• Exposure: IVC Left cubital fossa.
• Fluid: NBM. NO IVF

Results:

• Elevated Troponin 35ng/L troponin
• 12 lead ECG: ST elevation (>2mm) V2, V3, V4
• A diagnosis of acute anterior STEMI is made

Recommendations:

Plan: 

• Supplemental oxygen if SpO2 < 93%
• Continuous cardiac ECG monitoring
• 12-lead ECG now, then every 30 minutes
• Keep in resuscitation bay (Triage category 2)

Blood tests:

• Troponin now, then again in 2 hours

Medications:

• Morphine 2.5mg IVI 2/24 (PRN maximum dose 10mg)
• Nitro-glycerine 600mcg SL (PRN maximum 3 doses);  if pain persists, consider IV Glyceryl Trinitrate infusion
• Clopidogrel 300mg PO STAT
• Heparin 5000IU IV STAT

As per STEMI reperfusion flowchart:

• Transfer to Cardiac Cath Lab for urgent primary PCI when ready (<90mins).
• If PCI delayed, give Tenecteplase 45mg IV as per PACSA  @ 1230pm

 

Guided Questions:

Question 1: (250 words)

Pick one (1) clinical manifestation and discuss the related pathogenesis:

1. Central crushing chest pain with radiation to the jaw or;
2. ST elevation or;
3. elevated Troponin (35ng/L)

 

Question 2: (500 words)

Pick one (1) intervention from each of the three (3) categories below.

For each intervention chosen, Provide one rationale for interventions selected form each category.

Use evidence and/or pathophysiology to support your answer.

 

Category 1 Non-pharmacological interventions	Category 2 Pharmacological interventions	Category 3 Reperfusion interventions
· Supplemental oxygen if SpO2<93% · 12 lead ECG within 10 minutes of arrival and then every 30 minutes · Troponin at 0 and 2 hours	· Morphine 2.5mg IV · Nitro-glycerine 600mcg SL · Aspirin 300mg · Heparin 5000iu IV · Clopidogrel 300mg	· Tenecteplase 45mg IV · Primary Percutaneous Coronary Intervention

Pathophysiology: STEMI

Student’s Name

Institutional Affiliations

Pathophysiology: STEMI

Question 1: Pathogenesis of Clinical Manifestations

ST-elevation myocardial infarction (STEMI) is a cardiovascular disease commonly diagnosed in adults and the elderly. The case study describes Mr. Raj Kumar, a 64-year-old male who has arrived in the emergency department complaining of crushing chest pain. Diagnostic information indicates that Mr. Raj has acute anterior STEMI.  The healthcare provider has confirmed the presence of three primary symptoms associated with STEMI namely; central crushing chest pain with radiation to the jaw, ST elevation, and elevated Troponin (35ng/L) (Wanamaker et al., 2019). The pathophysiology of elevated Troponin is linked with myocardial damage (Chaulin, 2021).  An abnormal level of troponin in the blood is used as a diagnostic and confirmatory measure for STEMI.

The myocardium tissue is made of cardiomyocytes which contain the Troponin-tropomyosin complex (TTC): troponin T, troponin C, troponin I, and tropomyosin. STEMI causes myocardial necrosis or apoptosis eventually leading to the breakdown of the TTC (Chauni, 2021). In patients with STEMI, the initial phase of cardiomyocyte necrosis triggers caspase enzymes and proteinases in the myocardium. These enzymes and proteinases break down the DNA and protein structures of the cells. The disintegration of the cells leads to the release of Troponin in the blood (Chaulin, 2021). The release of Troponin from cardiomyocytes causes predictable kinetics which guides healthcare providers to measure the blood levels of troponin to establish the severity of STEMI. According to Cediel et al. (2017), any pathological condition that causes damage to cardiomyocytes causes excessive release of troponin in the blood. When establishing STEMI diagnosis and assessing disease prognosis, healthcare providers usually monitor changes in the blood levels of troponin over time.

 

 

 

Question Two: Evidence-Based Interventions

Non-pharmacological Interventions Category: Troponin at 0 and 2 hours

Non-pharmacological interventions have proven effective in improving STEMI symptoms among patients. The chosen non-pharmacological approach for Mr. Raj is conducting a blood test to assess the blood troponin levels now and 2 hours later. The rationale for testing blood troponin levels is to observe how its levels are changing. A reduction in blood troponin levels in Mr. Raj’s case will be a sign of reduced myocardial damage (Ndrepepa et al., 2018). The types of blood tests that are commonly conducted to assess the blood level of troponin in patients with cardiovascular problems are high-sensitivity troponin assays. High-sensitivity troponin assay should be initiated at 0/1 hours. Chew et al. (2019) conducted a study to examine the effectiveness of a 0/1 hour troponin test in monitoring blood troponin levels of patients. Findings from the study reveal that measuring blood troponin within 0/1 hours promoted effective monitoring of patients leading to speedy discharge. Similar findings are supported by Papendick et al. (2017). Troponin test conducted within 0/1 hours enables the healthcare provider to predict the possible direction that a patient’s prognosis might take.

Pharmacological Interventions Category: Clopidogrel 300 mg

Clopidogrel is an evidence-based pharmacological intervention for treating STEMI. The rationale for choosing the intervention is supported by its efficacy in preventing ischemic attacks in patients with STEMI. Additionally, Clopidogrel administered at a dose of 300 mg has been found to be effective and safe in improving STEMI symptoms (Cakal et al., 2021; Tran et al., 2019). As Tran et al. (2019) explain, Clopidogrel is often used together with Aspirin to help reduce complications from myocardial infarction. The authors further assert that STEMI patients who are treated with Clopidogrel are less likely to develop ischemic events. Drug efficacy, safety, and cost are key factors to consider when selecting medications for patients. Cakal et al. (2021) explain that Clopidogrel is a safe drug with high efficacy levels. Besides, the drug is less expensive when compared with other STEMI medications. It is important to maintain the dose at 300mg unless the patient has developed complications or is not responding to the regimen.

Reperfusion Interventions Category: Tenecteplase 45 mg IV

Reperfusion interventions are commonly administered to patients with STEMI to prevent cardiovascular complications and improve outcomes. The chosen reperfusion intervention for Mr. Raj is Tenecteplase 45 mg IV. According to Li et al. (2022), Tenecteplase produces promising outcomes when used as a reperfusion therapy in patients with ischemia. The authors indicate that it takes about 4.5 hours to generate an improvement in disease symptoms. Warach et al. (2020) indicate that Tenecteplase is an evidence-based fibrinolytic medication that helps to improve symptoms of STEMI. Patients who are treated with the drug have a significantly reduced risk of developing systemic hemorrhages and ischemic events. Implementing the three categories of interventions with Mr. Raj will enhance disease management and promote the realization of positive health outcomes. Precisely, the healthcare provider should test troponin at 0 and 2 hours, prescribe Clopidogrel 300 mg, and recommend Tenecteplase 45 mg IV. Published evidence supports the safe use of these interventions in STEMI patients.

 

 

 

 

 

 

 

 

 

 

References

Cakal, S., Cakal, B., Güven, Z., Tosu, A. R., Kalyoncuoglu, M., Biter, H. I., Apaydın, Z., Karaca, I. O., Belen, E., & Can, M. M. (2021). Switching Ticagrelor to 600 mg or 300 mg Clopidogrel loading bridge in patients with unstable asngina. Journal of Clinical Medicine, 10(11), 2463. https://doi.org/10.3390/jcm10112463

Cediel, G., Rueda, F., García, C., Oliveras, T., Labata, C., Serra, J., Núñez, J., Bodí, V., Ferrer, M., Lupón, J., & Bayes-Genis, A. (2017). Prognostic Value of New-Generation Troponins in ST-Segment-Elevation Myocardial Infarction in the Modern Era: The RUTI-STEMI Study. Journal of the American Heart Association, 6(12), e007252. https://doi.org/10.1161/JAHA.117.007252

Chauin A. (2021). The main causes and mechanisms of increase in cardiac troponin concentrations other than acute myocardial infarction (part 1): physical exertion, inflammatory heart disease, pulmonary embolism, renal failure, sepsis. Vascular Health and Risk Management, 17, 601–617. https://doi.org/10.2147/VHRM.S327661

Chaulin A. M. (2021). Cardiac Troponins Metabolism: From Biochemical Mechanisms to Clinical Practice (Literature Review). International Journal of Molecular Sciences, 22(20), 10928. https://doi.org/10.3390/ijms222010928

Chew, D. P., Lambrakis, K., Blyth, A., Seshadri, A., Edmonds, M., Briffa, T., Cullen, L. A., Quinn, S., Karnon, J., Chuang, A., Nelson, A. J., Wright, D., Horsfall, M., Morton, E., French, J. K., & Papendick, C. (2019). A randomized trial of a 1-hour troponin T protocol in suspected acute coronary syndromes: the rapid assessment of possible acute coronary syndrome in the emergency department with high-sensitivity troponin T study (RAPID-TnT). Circulation, 140(19), 1543–1556. https://doi.org/10.1161/CIRCULATIONAHA.119.042891

Li, S., Campbell, B., Schwamm, L. H., Fisher, M., Parsons, M., Li, H., Pan, Y., Wang, Y., & TRACE II investigators (2022). Tenecteplase reperfusion therapy in acute ischaemic cerebrovascular events-II (TRACE II): rationale and design. Stroke and Vascular Neurology, 7(1), 71–76. https://doi.org/10.1136/svn-2021-001074

Ndrepepa, G., Kufner, S., Hoyos, M., Harada, Y., Xhepa, E., Hieber, J., Cassese, S., Fusaro, M., Laugwitz, K. L., Schunkert, H., & Kastrati, A. (2018). High-sensitivity cardiac troponin T and prognosis in patients with ST-segment elevation myocardial infarction. Journal of Cardiology, 72(3), 220–226. https://doi.org/10.1016/j.jjcc.2018.02.014

Papendick, C., Blyth, A., Seshadri, A., Edmonds, M., Briffa, T., Cullen, L., Quinn, S., Karnon, J., Chuang, A., Nelson, A. J., Horsfall, M., Morton, E., & Chew, D. P. (2017). A randomized trial of a 1-hour troponin T protocol in suspected acute coronary syndromes: Design of the Rapid Assessment of Possible ACS In the emergency Department with high sensitivity Troponin T (RAPID-TnT) study. American Heart Journal, 190, 25–33. https://doi.org/10.1016/j.ahj.2017.05.004

Tran, H., Mehta, S. R., & Eikelboom, J. W. (2019). Clinical update on the therapeutic use of clopidogrel: treatment of acute ST-segment elevation myocardial infarction (STEMI). Vascular Health and Risk Management, 2(4), 379–387. https://doi.org/10.2147/vhrm.2006.2.4.379

Wanamaker, B. L., Seth, M. M., Sukul, D., Dixon, S. R., Bhatt, D. L., Madder, R. D., Rumsfeld, J. S., & Gurm, H. S. (2019). Relationship between troponin on presentation and in-hospital mortality in patients With ST-Segment-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention. Journal of the American Heart Association, 8(19), e013551. https://doi.org/10.1161/JAHA.119.013551

Warach, S. J., Dula, A. N., & Milling, T. J., Jr (2020). Tenecteplase thrombolysis for acute ischemic stroke. Stroke, 51(11), 3440–3451. https://doi.org/10.1161/STROKEAHA.120.029749