Literature Review
Physicians always encounter innumerable number of patients with chest pains every day. The cause of these chest pains cannot always be pinpointed to a single health factor. However, veritably a good percentage of these chest pain cases are traced to a wide range of heart diseases. Acute Coronary Syndrome is one such heart disease that has been found to be a possible causation of the chest pains that are incessantly encountered by physicians. Commonly abbreviated as ACS, Acute Coronary Syndrome results in the blockage of some parts or the heart’s entire coronary arteries.
Definition
Acute Coronary Syndrome (ACS) is a cardiac condition with an unpredictable pattern of presentation that occurs when there is an impairment or complete interruption of flow of blood in the coronary arteries (Mulryan, 2010) leading to a condition that is conventionally known as myocardial ischemia (Overbaugh, 2009). Crawford (2003) describes ACS as the symptoms resulting from a lack of balance between oxygen supply and demand to the cardiac cells(as noted by Wang and Magee, 2005). Myocardial ischemia is a condition in which the heart is deprived of oxygen and other nutrients that are essential for its myogenic activities (Overbaugh, 2009). Normally, the heart, as a large muscle, is served with the responsibility of pumping blood to parts of the body. In doing this, the heart supplies oxygen and other all-important nutrients to the body cells also removing the harmful by-products produced by these cells and hence an ineffective (or interrupted) supply of blood to the cells coupled with a pile up of uncollected by-products of metabolism is overly harmful to the cells (Mulryan, 2010). The heart is made up of cells which are also dependent on oxygen and nutrients contained in the blood pumped by the heart through the coronary arteries hence a blockage of a portion of the coronary arteries due to the formation of a blood clot or a thrombus may result in the death of part of the heart muscle (Mulryan, 2010).
Prevalence
A plethora of literatures point to the fact the ACS is increasingly becoming prevalent globally. Overbaugh (2009), in her article reports that by 2006 close to 1.5 million cases of primary and secondary diagnosis of ACS were recorded in America. Squizzato, Romualdi, Dentali, & Ageno (2011) echo Goldstein (2006) contention that Transient ischemic attack (a colloquial name for ACS), which according to Gaziano (2007) causes twice as many deaths as HIV, Tuberculosis and malaria combined yearly (as cited in Taylor et al., 2012) and is the third leading cause of fatalities in industrialized countries. As Taylor et al., 2012 further reports, starting from 1990, the number of incidences of Ischaemic heart diseases is expected to have increased by close to 30% in men and almost 50% in women by the year 2020. The estimates further point to the fact that men in developed countries are expected to record the highest increase in Ischaemic heart disease case (127%) compared to their female counterparts who are expected to experience a 120% increase.
Pathophysiology of Acute Coronary Syndrome
The causation of ACS is attributed to aggregation of platelets as well as the formation of thrombus as a result of disruption of the atherosclerotic plaque that is most commonly triggered by hypertension, smoking, diabetes or hyperlipidaemia (Marshall, 2011; Overbaugh, 2009). Other activities that are known to increase sympathetic stimulation and vasoconstriction are also potential causes of plaque disruption and coronary thrombosis. Additionally, clotting of blood in the coronary artery may be occasioned by hypercoagulability of the blood as well as the hyperreactivity of the platelets (Marshall, 2011). Notably, ACS can also be caused by causation factors that are by all means not atherosclerotic. Non- atherosclerotic etiology of ACS might include; congenital abnormality or complication of the cardiac muscles (Marshall, 2011). Overbaugh (2011) purports that, researchers initially believed that it is the growing plaque that would reach a point of blocking the coronary arteries, a notion that has been overruled after empirical researches shown that it is the rupture of a plaque that result in the occlusion. A rupture on the surface of an existing plaque causes blood clotting facilitated by the release of chemicals that favor blood clotting. The clot has the potential of growing to the extent of blocking blood flow (occlusion). In other instances, a small sized clot particle can be detached from a larger clot and carried by the flowing blood to a smaller vessel where it then occludes blood flow.
Just like all the other body cells, the cells of the heart muscle also require oxygen in order to maintain their “contractility and electrical stability” essential for their normal functioning (Overbaugh, 2009). In the event that they are deprived of oxygen, the cells gradually resort to anaerobic respiration, which leads to the production of limited amounts of energy. Inherently, acidosis results because of the accumulation of sodium ion in the cells as well as hydrogen ion and lactate. According to Overbaugh (2009) this occurs in two phases starting with the ischemic phase during which the cell respire both aerobically and anaerobically followed by the injury phase when the cells respire only anaerobically are as a result of continued deprivation of oxygen. About 20 minutes into the injury phase if the supply of oxygen is not restored, a myocardial necrosis as a result of the myocardial infarction (ST elevation Myocardial infarction ad non ST elevation myocardial infarction) becomes inevitable; ST elevation Myocardial infarction (STEMI) occurs when there is complete occlusion of blood flow in the coronary artery while non-ST elevation Myocardial infarction (NSTEMI) occurs when there is partial occlusion of flow of blood in the coronary artery. The result is a decreased cardiac output with the supplied of blood only maintained to major organs and peripheral tissues of the body, (Hoenig, Aroney, 2010).
Signs and Symptoms of ACS
Symptomatically, the expression of ACS is overly dependent on the extent of occlusion. With chest pain being perhaps the most common symptom of ACS, the duration of the chest pain varies with the type of myocardial infarction; patients with NSTEMI experience the longest duration of chest pains unlike their counterparts experiencing STEMI. Other symptoms that point to the possibility of ACS include; breathing problems, lightheadedness, hypo and hypertension as well as an abnormal cardiac rhythm. Canto, Canto, Goldberg & Hand (2009) uphold that ACS patients, particularly female patients, frequently suffer from indigestion, nausea, vomiting, diaphoresis, faintness or dizziness, and fatigue. The patients additionally experience pericardial chest discomfort that radiate to the arm, shoulder and possibly to the neck. ACS can also be expressed in the form of cardiac arrest or stoke like symptoms.
Assessment and Diagnosis of ACS
Physical assessment stands out as one of the most effective assessment tools for ACS. During physical assessment, the physician seeks information about the blood flow of the patient while also looking for cues that might give insight to the possibility of pulmonary edema or a cardiogenic shock. Additionally, physical assessment can reveal crackles in the base of the lung in most patients experiencing ST E Myocardial Infarction and abnormal jugular venous pressure. Physical assessment is also utile in helping the physician rule out the possibility of other ACS somewhat related complications such as pulmonary embolism and pericarditis (Bassand et al., 2007 as cited in Marshall, 2011)
Several tests exist to help on the diagnosis of ACS by physicians. Physicians after carrying out preliminary physical assessment often conduct an Electrocardiogram (ECG) in a bid to diagnose a heart attack to patients presenting chest pains; unlike a normal heart, a heart experiencing occlusion-related effects will not conduct electric impulses as expected during ECG giving insight to the possibility of a heart attack. As Marshall (2009) averts, a “1mm in at least two contiguous limb leads or 2mm in two contiguous chest leads” is a clear indicant of an acute STEMI. Such a discovery prompts the physician to begin a reperfusion therapy aimed at unblocking the occluded coronary arteries. ACS can also be diagnosed through conducting blood tests. This assertion underscores the fact that certain enzymes always leak into the heart in the event that the heart is damaged following a heart attack. Echocardiogram, Echocardiogram, Chest X-ray, Nuclear scan, Computerized tomography (CT) angiogram, and Coronary angiogram (cardiac catheterization) are set of descriptively more invasive diagnostic tools used for the detection of ACS.
Appropriate Nursing Interventions
There are multiple interventions that have been developed which are currently considered very utile in the managements of Acute Coronary Syndrome. The main methods are the use of medication, surgical interventions and the use of special equipment inserted into the patient’s vessels to limit obstruction. Hoenig, Aroney and Scott (2010) argue that, the routine invasive strategy and the conservative strategy are the two main interventions used in the management of Acute Coronary Syndrome. The Invasive strategy is an approach where a catheter is inserted to image the patient’s coronary artery , and if atherosclerotic narrowing is found, then it is dilated through a balloon catheter, (Hoenig, Aroney and Scott 2010). The conservative strategy uses drugs in the treatment, nonetheless, if pain and other related symptoms persist, then other approaches such as noninvasive tests, imaging, coronary angiography and revascularization may be carried out.
The most basic approach towards the management of ACS is the combined treatment of oxygen, aspirin and beta blockers coupled with immediate recanulisation therapy, (Wang and Magee, 2011 and Magee, Campbell, Moher and Rowe, 2010). Since ACS is caused by the constriction of the arteries mainly from blood clots, drugs such as aspirin prevents the formation of clots while others such as heparin thins the blood hence in cases of attack, the drugs can relieve the problem. Megee, Sevcik, Moher and Rowe (2010) contend that there are two types of heparin; Unfractionated heparin (UHF) and Low molecular weight Heparin with trials indicating that both are equally effective in preventing death. Nonetheless, UFH has been found to cause serious but rare adverse side effects although it thins the blood. There are other pharmacological intervention strategies proposed by researchers such as the one described by Marti-Carvajal, Sola, Lathyris and Salanti (2009), which uses a series of B-complex vitamins; folic acid (B9), Pyridoxine (B6) and Cyanocobalamin (B12). The rationale behind the intervention is that, B-complex vitamins transform and excrete tHcy metabolism pathways thereby reducing their high levels which are directly linked with increased Acute Coronary Syndrome.
According to Greenhalgh et al (2011), another strategy of controlling ACS by restoring blood supply in the heart is through Transluminal Coronary Angioplasty (PTCA) an intervention in which a small inflated elongated balloon is attached to the site of the plaque compacting the materials against the vessel wall as well as increasing blood flow. The devices are expendable and only serve as temporary measures to relieve coronary obstructions, besides; high success rates are associated with their use. The devices are of two categories, the Bare Metal Stents (BMS) and the Drug-eluting Stenets (DES). The former are specialized metallic devices inserted into the vassell and are noted for their high success and low complications rate although there is a likelihood of re-narrowing of the treated vessel. DES on the other hand, in addition to narrowing the constricted vessel, releases an antiproliferative agent which limits cell growth thereby limiting constriction.
Invasive, Conservative, Anti-hypersensitive and the Exercise approach
Researchers have debated on the better strategy between the invasive and the conservative approaches. The invasive strategy has been found to reduce further hospitalizations or incidences of pain. Long term followups have indicated that it slims the chances of suffering a heart attack within five years following the procedure by 22%. The downside of the invasive strategy is that it increases the bleeding risk and may lead to procedure related heart attack, (Hoenig, Aroney and Scott, 2010). Another approach is the use of antihypertensive or blood pressure lowering drugs which lower the blood pressure when administered hence reducing the chances of a heart attack for individuals suffering from Acute Coronary Syndrome, (Perez, Musini and Wright 2010).
The inclusion of exercise coupled with education and psychological support has also been used as an intervention strategy for acute coronary syndrome. A review by Heran et. al (2011) defines exercise-based cardiac rehabilitation as a strategy that aims to restore people with Coronary Heart Diseases to health by using a combination of regular exercise, education and psychological support. The intervention is comprehensive; defined as coordinated sum of interventions which incorporate the best physical, psychological and social conditions so that patients with acute cardiovascular disease may through their effort be able to resume optimal functioning and be able through consistent effort to reverse the effect of the disease, (Heran et. al 2012). The intervention is quite complex as it takes into considerations a number of factors which include; behavior change, psychological support, strategies that target and avert risk factors of cardiovascular disease, exercise, a variety of therapy and risk factor education. The strategy works as exercise directly benefits the heart and ‘coronary vasculature’ inclusive of autonomic tone, coagulation and clotting factors, development of coronary collateral vessels, and increases myocardial oxygen demand thereby leading to a healthier heart. (Heran et. al 2012).
Conclusion
Acute Coronary Syndrome remains a common hospital presentation with a significant mortality and risk of recurrence. A review of aspects such as prevalence, pathophysiology, signs and symptoms, assessment and diagnosis and the appropriate nursing interventions is imperative as the findings are relevant to physicians, health systems, health providers and patients. The review is also critical as it helps in determining various clinical interventions and their impact following acute cardiovascular event. ACS, which results from a myocardial oxygen demand and supply imbalance is quite prevalent causing close to 1.5 million deaths in 2004. Individuals should practice healthy lifestyles, since ACS’s origin is attributed to lifestyle habits and diseases such as hypertension, diabetes, and hyperlipidaemia. Signs such as lightheadedness, breathing problems, hypertension and abnormal cardiac rhythm should prompt a clinical assessment on the sufferer since, ACS may at times be difficult to detect. It is imperative to note that there are multiple interventions key among them being; the combined use of oxygen, aspirin and beta blocker, restoration of the heart’s blood supply through the use of Transluminal Coronary Angioplasty, the use of antihypertensive lowering drugs, and the use of exercises all of which have varied outcomes dependent on the patient.
References
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