Background

Cardiac health conditions are becoming an increasing burden on the healthcare system globally. STEMIs, also commonly known as heart attacks, are prevalent in adults and the elderly, and their symptoms are frequently recognizable to the general public. However, despite the awareness of most individuals regarding the symptoms of a heart attack, more research needs to be conducted about how these cardiac conditions and the subsequent likelihood of readmission differ across groups. Racial and ethnic groups have shown major differences in their risk factor and prognoses of ACS. Christopher S.G Murray and his colleague conducted a study comparing the differences in STEMI management and post-hospitalization outcomes in non-Hispanic Blacks (NHB), non-Hispanic Whites (NHW), and Hispanic/Latinos (H/L) [7]. By understanding these differences, the healthcare system can work to spread awareness on improving cardiac health as well as mitigating complications and readmissions post-hospitalization.

Methods

The study used a registry of patients hospitalized for STEMIs in the Montefiore Health System, a collection of hospitals across New York, from May 2008 – December 2014. Individuals had just been diagnosed with STEMIs and were about to undergo primary revascularization. Racial and ethnic backgrounds were self-identified by the participants.

The heart can be analyzed through an electrocardiogram (ECG). A normal rhythm is shown on the left side of Figure 3, where the ST segment is at its baseline. On the right side of Figure 3, the ST-segment is more elevated than it normally should be, which can indicate abnormalities in the heart, such as heart attacks or a temporary lack of oxygen. As shown in Figure 4, there are 12 different sections, or leads,that look at different parts of the heart in an ECG.

 In order to be involved in the study, participants had to have experienced a lack of oxygen to the heart that lasted over 20 minutes. Each waveform represents a full cardiac cycle (x-axis), and each small box represents 1 mm, in which elevation is measured on the y-axis. ST-elevation had to be ≥ 2 small boxes in men or 1.5 small boxes in women in the V2-V3 leads, which look at the front (septal and anterior regions) of the heart; alternatively, ST-elevation had to be ≥ 1 small box in any 2 other leads that look at the same region of the heart for both sexes. Additionally, increases in the Troponin protein, which are elevated in the blood if there is damage to the heart were also analyzed. If any of the following medical conditions were present, participants were not included in the study: pregnancy, diabetic ketoacidosis. end-stage renal disease on hemodialysis, and shock cases during the 2008-2009 years.

The study measured death post-hospitalization, general readmissions, cardiovascular disease (CVD) associated readmissions, and heart failure (HF) associated readmissions.

Figure 3. A depiction of the difference between a normal waveform and a waveform demonstrating ST-elevation on an ECG. [2]

Figure 4. A sample 12-lead and the region of the heart that each section analyzes. Each lead is listed on the left side of each section [3]

Results

The study found that the types of coronary vessel damaged and type of intervention did not vary across race. Similarly, the severity of the STEMI did not vary across races as evidenced by similar Troponin levels, which indicate damage to the heart. H/L patients had the lowest socioeconomic status (SES) of all 3 groups with 70% of participants having existing hypertension (HTN). Overall, H/L and NHBs had higher incidences of HTN, diabetes mellitus (DM), and dyslipidemia, as shown in Table 1. The study also found that more NHB and H/L were prescribed Renin-Angiotensin-Aldosterone-System (RAAS) antagonists, which regulate blood pressure, and hypoglycemic meds, which work to bring down blood glucose levels, compared to NHW at discharge. Lastly, the study also found that re-hospitalizations (across all categories) for NHB and H/L were greater than NHW, and there were no significant differences in mortality across the groups as shown in Table 2.

Table 1. The number of participants with pre-existing medical conditions, such as hypertension, diabetes mellitus, and dyslipidemia.

	HTN	DM	Dyslipidemia
H/L	314	192	249
NHB	187	93	136
NHW	163	46	137

Table 2. The types of readmissions (general, cardiovascular disease, and heart failure) or deaths post-STEMI treatment.

	General Readmission	CVD Readmission	HF Readmission	Deaths
H/L	238	125	49	75
NHB	142	66	28	50
NHW	134	57	15	51

Discussion

As seen in Table 1, there were higher incidences seen in NHB and H/L with regards to HTN, DM, and dyslipidemia. These numbers show that there are differences in pre-existing conditions across these ethnic groups, which may be due to genetic differences, cultural factors, such as diet, or socioeconomic differences. In DM, consistently high glucose levels can damage blood vessels, which can further lead to conditions such as HTN or CVD, and poorer cardiac health. Dyslipidemia is a condition characterized by increased lipid, or fat, levels in the bloodstream. Long-term build-up of lipids in the blood vessels can begin to block arteries as shown in Figure 1. In this manner, it is expected that these two groups have higher prescriptions of RAAS antagonists and hypoglycemic medications post-hospitalization as they have greater incidences present upon admission. H/L were found to have the lowest SES, which may explain the increased incidences of pre-existing medical conditions, as finances and distance to grocery stores may negatively impact the type of food these populations consume [6]. In this manner, socioeconomic factors may impact the care that H/L and NHBs can receive post-hospitalization, such as health insurance, as well as medication costs as these communities may not be able to afford certain types of therapeutic drugs. Consequently, adherence also becomes an issue due to the cumulative amount of money that may get spent in the long-term. Thus, these factors may influence the higher readmission rates seen in Table 2 [6]. However, it is interesting to note the similar mortality rates across all races post-hospitalization, which may suggest better education on dealing with these medical conditions, improved compliance to medications, and better eating habits. It may be beneficial to study the impact of this finding in future studies. Overall, the study by Murray et al. shows that pre-existing medical conditions and post-STEMI re-hospitalizations may be impacted by SES and ethnicity, and it is important to consider these factors when coming up with post-STEMI treatment plans that benefit and support the patient’s health in the long-term.

Limitations

This study utilized data from an inner-city, which may limit its generalizability to other population sizes and types. The study also did not delve deeper into different SES factors such as education level and how that may impact the health conditions upon initial hospitalization. Similarly, the study did not have more in-depth ethnic information on the participants and thus, could not investigate different Hispanic subgroups further. Furthermore, the study used the Montefiore Health System with additional data from the North Bronx Health Network, where individuals without health insurance were more likely to frequent, which may explain the low-SES rates seen in the study groups.

Conclusion

By addressing disparities in how the healthcare system manages STEMIs, we can mitigate the risk factors. These findings may be indicative of re-hospitalization in certain ethnic groups and can provide both researchers and hospitals better information on how to prevent these future complications as well. Overall, this study underscores the importance of representation in research and making sure that all ethnic, racial, and class groups are considered when designing healthcare systems that impact these corresponding populations.

Definitions

Acute Coronary Syndrome (ACS) – a group of medical conditions that result in decreased blood flow and oxygen to the heart [8].

Ischemia – a lack of oxygen to the tissue.

ST-elevation myocardial infarction (STEMI) – a medical condition characterized by a blockage in the coronary arteries, which supply blood to the heart, resulting in a lack of oxygen to cardiac tissues and consequent tissue damage as shown in Figure 1 [4].

Primary revascularization – restoring blood flow to the heart after partial/complete blockages. This procedure can be done in multiple ways and is case-dependent as shown in Figure 2.

Figure 1. A comparison between a healthy coronary artery and a coronary artery with plaque buildup that can impede proper blood flow.  [1]

Figure 2. The types of primary vascularization. [5].

Reference

1. Coronary artery disease (atherosclerosis). University of Ottawa Heart Institute. (2024, October 21). https://www.ottawaheart.ca/heart-condition/coronary-artery-disease-atherosclerosis
2. Deshpande, A. (2014). St-segment elevation: Distinguishing st elevation myocardial infarction from st elevation secondary to nonischemic etiologies. World Journal of Cardiology, 6(10). https://doi.org/10.4330/wjc.v6.i10.1067
3. E C G leads. Natalie’s Casebook. (n.d.). https://www.nataliescasebook.com/tag/e-c-g-leads
4. Elendu, C., Amaechi, D. C., Elendu, T. C., Omeludike, E. K., Alakwe-Ojimba, C. E., Obidigbo, B., Akpovona, O. L., Oros Sucari, Y. P., Saggi, S. K., Dang, K., & Chinedu, C. P. (2023). Comprehensive review of st-segment elevation myocardial infarction: Understanding pathophysiology, diagnostic strategies, and current treatment approaches. Medicine, 102(43). https://doi.org/10.1097/md.0000000000035687
5. Goodney, P. P., Dzebisashvili, N., & Goodman, D. C. (2014). Diabetes and peripheral arterial disease: Putting patients at high risk for amputation. Variation in the Care of Surgical Conditions: Diabetes and Peripheral Arterial Disease: A Dartmouth Atlas of Health Care Series [Internet].
6. Havranek, E. P., Mujahid, M. S., Barr, D. A., Blair, I. V., Cohen, M. S., Cruz-Flores, S., Davey-Smith, G., Dennison-Himmelfarb, C. R., Lauer, M. S., Lockwood, D. W., Rosal, M., & Yancy, C. W. (2015). Social determinants of risk and outcomes for cardiovascular disease. Circulation, 132(9), 873–898. https://doi.org/10.1161/cir.0000000000000228
7. Murray, C. S., Zamora, C., Shitole, S. G., Christa, P., Lee, U. J., Bortnick, A. E., Kizer, J. R., & Rodriguez, C. J. (2022). Race-ethnic differences of st -elevation myocardial infarction: Findings from a New York Health System Registry. Ethnicity & Disease, 32(3), 193–202. https://doi.org/10.18865/ed.32.3.193
8. Singh, A., Grossman, S. A., & Museedi, A. S. (2023, July 10). Acute coronary syndrome. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK459157/

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