Simple Risk Stratification based on Killip Classification and the Six-minute Walk Test Borg Scale for Outcomes of Acute Coronary Syndrome for Papuanese People in Rural Hospital

Background: Accurate risk stratification for untoward outcomes after acute coronary syndrome patients may help clinicians guide the type and intensity of therapy. Unfortunately, most of the Papuanese people face difficulties in accessing sophisticated medical treatment. Aims: The aim of this study was to determine the simplest but most accurate risk stratification for ACS patients treated in rural hospital. Methods: This was a cross-sectional study conducted in Sele Be Solu Regional Hospital at Sorong Regency in West Papua Province. Fifteen unselected patients from September 2019 to March 2020 period with ACS were prospectively studied. All the data were collected from medical records. Results: Subject characteristics mostly were male (80%) and mean age was 54 years, (13,3%) subjects were age less than 45 years. The most diagnosed ACS type was STEMI (73,3%). Conclusion: In Papuanese patients with ACS in rural hospital, those at highest risk can be identified using Killip classification and The Six-minute Walk Test Borg Scale as short term predictor for ACS patients’ outcome. Original Research Simple Risk Stratification based on Killip Classification and the Six-minute Walk Test Borg Scale for Outcomes of Acute Coronary Syndrome for Papuanese People in Rural Hospital Ahmad Z. Alhamid1*, Herlina Yulidia1,2, Intan I. Supriatna3 1 Faculty of Medicine, Universitas Papua, Sorong, Indonesia. 2 Sele Be Solu Regional Hospital, Sorong, Indonesia. 3 Universitas Muhammadiah Sorong, Sorong, Indonesia.


Introduction
According to World Health Organization, cardiovascular diseases are the world's deadliest disease with 17, 9 million deaths annually [1] . Acute coronary syndrome (ACS) is one of cardiovascular diseases that contributed to 7 million deaths worldwide [2] . ACS is a spectrum of cardiovascular disease caused by sudden blockage or narrowing of the coronary vessels [4,5] . Atherosclerotic plaque rupture is a common mechanism underlying blockage of the coronary vessels in ACS patients [4,5] . Atherosclerosis is inflammation of the artery walls due to lipid buildup. [3,4,5] ACS spectrum including ST segment elevation myocardial infarction (STEMI), non ST segment elevation myocardial infarction (NSTEMI) and unstable angina pectoris (UAP). The most common clinical manifestation of ACS is heavy chest pain, dyspnea, decrease awareness and loss of consciousness [4,5,6] .  [5] . The un-modifiable factor is genetic. [5] The incidence of re-hospitalization and postdischarge mortality is also quite high in ACS patients in the Asia-Pacific region [3] . Most patients develop cardiac decompensation after having ACS [6] . Killip classification was invented in the mid-60s to minimize the risk of mortality for myocardial infarct (MI) patients during their hospitalization [7] . In this modern era, Killip classification is still being used to measure the clinical severity of cardiac decompensation among ACS and MI patients [7,8] .
However, many other scientists are proving the usage of Killip classification as a predictor for ACS patients' mortality and morbidity. According to Zadok et al, Killip classification has been shown to be a predictor of 1-year post-discharge cardiovascular function for ACS patients [8] . Study by Mello et al. said the 5-year prognosis for patients with myocardial infarction can be assessed by the Killip classification at the admission. [9] There is no data available that shows short term predictor factor of Killip classification for ACS patients, so this study was conducted to determine Killip classification as short term predictors of ACS patients' outcome through the six-minute walk test (6MWT) Borg scale in Sele Be Solu Regional Hospital.

Material and Methods
This cross-sectional study was based on medical records of ACS patients in Sele Be Solu Regional   [11] .
Other study by Ricci et al (2017) examined the risk of young adult women on the incidence of ACS, obtaining data from 8% of ACS subjects aged <45 years. [12] Six-minute walk test (6MWT) is a method of measuring the functional ability of a person's cardiovascular and respiration systems through walking for 6 minutes [13,14,15] . The components measured in 6MWT are distance reported in meters or feet, oxygen saturation, blood pressure, heart rate, dyspnea and the patient's fatigue level. The Borg scale is a method used to measure a person's perception of the load of his physical activity [16] . The Borg scale is a numeric range from 0 to 10, which can be interpreted as a level of physical activity from light to heavy [16] . Six-minute walk test and Borg scale measurement are included as components of pre-discharge cardiac training tests for patients with myocardial infarction, ACS, heart failure, post-invasive cardiovascular therapy, and heart or lung transplant [17] . The Borg scale was used to measure ACS patients' cardiovascular function after they did 6MWT.
Theoretically, patients who have decreased cardiorespiratory function tend to experience increased respiratory effort during normal daily physical activities that do not impose a burden on normal people [16,18] . Research by Hamilton et al (1996) proved that decreased cardiorespiratory function had an effect on increased respiratory effort and was associated with patient perceptions of the level of physical activity undertaken [18] . The increasing respiratory effort in patients with cardiorespiratory disorders was measured using the Borg scale and it was found that they tended to be in the heavy category. [18] The  [8] . However, a wide CI 95% (2,1-825,7) indicated that the results of the study were less accurate in stating the chance for ACS patients with ≥Killip II experienced worsening post-treatment cardiovascular system function.
The obstacle in this study was the time to collect data at the same time as the COVID-19 pandemic so that the medical rehabilitation clinic did not provide patient care. Thus, no more subjects could be obtained.

Conclusion
From the study we can conclude that most of our subjects were male (80%), with the most ACS type was STEMI (73,3%) and mean age were 54 years.