The effect of Killip class on the development of anxiety in intensive care unit patients with acute myocardial infarction

Nurdan Çetin; Nazire Şeker; Saime Güleç; Esin Ercanli; Gamze İğneci Ataş; Oktay Şenöz

doi:10.5606/e-cvsi.2025.1836

Abstract

Objectives

This study aims to investigate the effect of Killip class on the development of anxiety and depression in patients admitted to intensive care unit (ICU) with acute myocardial infarction (AMI) and to identify risk groups in terms of anxiety and depression.

Patients and methods

Between May 2024 and October 2024, a total of 200 patients (140 males, 60 females; mean age: 61.4±12.1 years; range, 31 to 89 years) with acute ST elevation MI (STEMI) and non-ST elevation MI (NSTEMI) were included. The Hospital Anxiety and Depression Scale (HADS) was administered within the first 24 h after the patients' treatment in the ICU was completed and the patients were transferred to ward.

Results

Anxiety was observed in 60 (30%) of the patients, while depression was observed in 93 (46.5%) of the patients. A total of 148 (74%) of the patients were Killip in Class I, while the others had a class other than Killip I. Having a class other than Killip I and prolonged ICU stay significantly increased the anxiety scores (p=0.003 and p=0.016). In the univariate and multivariate regression analysis, having a classification other than Killip I was found to be an independent predictor of ICU anxiety (odds ratio [OR]=0.456; 95% confidence interval [CI]: 0.210-0.993; p=0.048).

Conclusion

Killip classification is an independent predictor of anxiety in AMI patients. Since patients with AMI, particularly those who are in Killip Class II-IV, are in the risk group for anxiety, it is of utmost importance to evaluate the anxiety status of these patients as soon as possible and to reduce the affecting factors by identifying them.

Keywords:

Acute myocardial infarction, anxiety, depression, intensive care unit

Introduction

Cardiovascular diseases are one of the major causes of morbidity and mortality in Türkiye and in the world.[1] According to the World Health Organization (WHO) and Turkish Statistical Institute (TurkStat) data, ischemic heart disease is the leading cause of death, which reveals the importance of investigating this disease in every aspect.[1,2]

Acute myocardial infarction (AMI) not only affects the quality of life of patients, but also causes psychological problems. Anxiety is common in patients with AMI during the acute phase. One of the main causes of anxiety is the fear of death. In addition, severe angina and other symptoms experienced by patients, hospitalization and related stressors can also cause anxiety, as patients feel that their health and life goals are threatened. While anxiety is at the forefront in patients in the first days, depression is more common in the following days. Post-AMI depression may be associated with the uncertainty experienced by individuals, physical limitations, anxiety about loss of function, anxiety about not being able to continue social life, and feelings of guilt about their past life.[3-5]

While AMI can cause psychological problems, psychological comorbidities which occur in patients can adversely affect the treatment process. Intense anxiety triggers activation of the sympathetic nervous system and increases the release of hormones such as adrenaline and cortisol, causing an increase in heart rate and blood pressure and increasing the workload of the heart, which can cause a more severe course of physical disease. Additionally, anxiety and depression may cause problems in adaptation to the primary disease. Due to these effects, providing psychological support to patients with high levels of anxiety and depression may improve the prognosis and reduce the rate of rehospitalization. In addition to the physical recovery process in these patients, their psychological states should also be carefully monitored.[3,6]

Killip classification is a classification system used to clinically evaluate the hemodynamic status of patients with AMI and to identify the risk of mortality.[7] It consists of four classes. Killip Class I is the lowest class with mortality risk (6%) without signs of heart failure. In Killip Class II, ventricular gallop rhythm (S3) and wet crackles can be seen in the lung bases, while in Killip Class III, there is acute pulmonary edema and the risk of mortality is around 38% and in Killip Class IV, the mortality risk (80%) is the highest class in which cardiogenic shock is seen.[7] Considering that the level of anxiety experienced by patients will differ depending on the severity of the disease and the nature of the symptoms, it is thought that the levels of anxiety and depression experienced by patients in different classes of AMI according to the Killip classification would vary.[8]

In the present study, we aimed to investigate the effect of Killip class on the development of anxiety and depression in patients admitted to intensive care unit (ICU) with AMI and to identify risk groups in terms of anxiety and depression.

Methods

This single-center, descriptive, cross-sectional study was conducted at Bakırçay University, Faculty of Medicine, Department of Cardiology between May 2024 and October 2024. Patients with acute ST elevation MI (STEMI) and non-ST elevation MI (NSTEMI) who met the universal definition of AMI were included. Inclusion criteria were as follows: being over 18 years of age, having been hospitalized in ICU for at least 24 h, and not having a diagnosis of depression or anxiety. Patients diagnosed with any psychiatric disease, those with limited cooperation, and those who developed impaired consciousness after AMI were excluded from the study. Finally, a total of 200 patients (140 males, 60 females; mean age: 61.4±12.1 years; range, 31 to 89 years) who were hospitalized in the ICU with the diagnosis of AMI were recruited. A written informed consent was obtained from each patient. The study protocol was approved by the Bakırçay University, Faculty of Medicine, Non-Interventional Clinical Research Ethics Committee (date: 21.05.2024, no: 2024-1618).

The study was conducted in accordance with the principles of the Declaration of Helsinki.

A data collection form including demographic and clinical characteristic data and laboratory results of the patients and the Hospital Anxiety and Depression Scale (HADS) were used. The data collection form contains a total of 27 questions and there are two sections in the form. The first section includes questions regarding sociodemographic characteristics such as age, sex, presence of hypertension, diabetes mellitus, hyperlipidemia, marital status, education, occupation, while the second section includes questions about descriptive characteristics specific to the patient's health status and ICU, such as type of admission to ICU, Killip class during admission, duration of angiography, duration of stay in ICU, status of mechanical ventilation, duration and method of mechanical ventilation, and previous stay in ICU.

The HADS scale contains 14 questions and the questions are scored on a four-point Likert scale. It has two subscales: HAD anxiety subscale (HAD-A) and HAD depression subscale (HAD-D). The HAD-A section assesses anxiety with seven questions and HAD-D section assesses depression with seven questions. Items 1, 3, 5, 6, 8, 10, 11 and 13 of the scale are for anxiety, and they gradually decrease and are scored as 3, 2, 1, 0. The other items 2, 4, 7, 9, 12 and 14 of the scale are for depression and are scored as 0, 1, 2, 3.

When the scores of items 1, 3, 5, 7, 9, 11 and 13 for the Anxiety Subscale are added. For the Depression Subscale, the scores of items 2, 4, 6, 8, 10, 12 and 14 are added. The minimum score that patients can get from both subscales is 0, and the maximum score is 21.

The cut-off points for the Turkish form of HADS were determined as 10 for the Anxiety Subscale (HAD-A) and 7 for the Depression Subscale.[9]

Statistical analysis

Statistical analysis was performed using the IBM SPSS version 25.0 software (IBM Corp., Armonk, NY, USA). Continuous data were expressed in mean ± standard deviation (SD) or median (min-max), while categorical data were expressed in number and frequency. The suitability of numerical variables for normal distribution was examined using the Kolmogorov-Smirnov test. The independent samples t-test was used to make comparisons between two groups of continuous variables. The relationship between categorical variables was examined using the Pearson chi-square or Fisher exact test. To identify independent risk factors on the development of anxiety, parameters with a p value of <0.1 were evaluated in the univariate regression analysis. Those with a p value of <0.05 were included in the multivariate regression analysis. A p value of <0.05 was considered statistically significant.

Results

Demographic and clinical characteristics of patients are summarized in Table 1. The mean anxiety score was 7.84±4.9 and the mean depression score was 7.36±4.8. Anxiety was observed in 60 (30%) of the patients, and depression was observed in 93 (46.5%).

While 148 (74%) of the patients were in Killip Class I, the others had a class other than Killip I.

Of the patients other than Killip I, 37 (71%) were in Killip II, 10 (19%) were in Killip III, and five (10%) were in Killip IV. A total of 115 (57.5%) of the patients had hypertension, 85 (42.5%) had diabetes mellitus, and 87 (43.5%) had hyperlipidemia. Of the patients, 117 (58.5%) had non-STEMI, 46 (23%) had inferior MI, 33 (16.5%) had anterior MI, and four (2%) had other MI (Table 1).

Coronary angiography was performed via radial access in 70 (35%) patients and via femoral access in 130 (65%) patients. Seventy-two (36%) patients had previous ICU hospitalization experience. The mean ICU hospitalization time was 2.1±1.7 (range, 1 to 12) days (Table 1).

Considering the factors affecting ICU anxiety, having a class other than Killip I and prolonged ICU stay significantly increased the anxiety score (p=0.003 and p=0.016, respectively). The factors which significantly increased the ICU depression score were determined as advanced age and prolonged ICU stay (p=0.043 and p=0.003, respectively). While no significant parameter affecting the anxiety score was found among the laboratory data of the patients, depression score was significantly increased by low calcium, total cholesterol, hemoglobin and hematocrit and high troponin (p=0.044, p=0.009, p=0.004, p=0.003 and p=0.01, respectively) (Table 2).

In the univariate and multivariate regression analysis performed to identify the independent predictors of ICU anxiety, having a classification other than Killip I was found to be an independent predictor (odds ratio [OR]=0.456; 95% confidence interval [CI]: 0.210-0.993; p=0.048) (Table 3).

Discussion

In the present study, we investigated the effect of Killip class on the development of anxiety and depression in patients admitted to ICU with AMI and identified risk groups in terms of anxiety and depression. Our study results showed that having a class other than Killip I was an independent risk factor for the development of ICU anxiety in patients with AMI.

To prevent ischemic heart diseases, which are the leading causes of death worldwide, all risk factors in the individual must be evaluated together. Previous studies have shown that the main independent risk factors for coronary artery disease (CAD) are being ≥45 years of age for men, being ≥55 years of age for women, being a smoker and having a chronic disease such as diabetes, hypertension and hypercholesterolemia.[10] In our study, the presence of these risk factors was observed in the majority of patients. The mean age of the patients was 61.4±12.1 years, 57.5% had hypertension, 42.5% had diabetes, 43.5% had hyperlipidemia and 55.5% were smokers, consistent with the literature.[10]

In the current study, 70% (n=140) of the patients were male patients. Similar to our study, in the studies conducted by Özer et al.[11] and Demirbaş and Kaya[3] examining anxiety and depression in patients diagnosed with MI, most of the participants were male. According to the Cardiovascular Risk Factors in Turkish Adults (TEKHARF) study, coronary heart disease was more common in men and the incidence of coronary-related mortality was 5.7 per thousand in men and 3.6 per thousand in women.[12]

Anxiety and depression are the most common psychological problems in patients with MI. In our study, according to the HADS questionnaire, the mean anxiety score of the patients was 7.84±4.9 and the mean depression score was 7.36±4.8. Sixty (30%) patients had high anxiety and 93 (46.5%) patients had high depression scores. Among similar studies in the literature, Semiz et al.'s[13] study of patients with AMI found anxiety in 24% of the patients and depression in 30%. In the study conducted by Kutlu et al.[14] including patients in ICU, the highest rates of anxiety (37%) and depression (36.5%) were seen in MI among all diagnoses. In their study, Dias et al.[15] found the rate of depression after AMI to be 41.6%. The results of some studies have shown that the rates of anxiety and depression are higher than our study. In their study with CAD patients, Ekici[16] reported anxiety in 72.4% of the patients, while Özer et al.[11] found anxiety in 100% of the patients and depression in 91.1% of AMI patients.

In the present study, while there was no significant difference in anxiety and depression scores according to sociodemographic characteristics such as sex, education and marital status, there was a significant difference between age and depression scores, and as age increased, depression scores increased. In their study, Aydemir et al.[5] found that depression increased with age. Akkaya et al.[17] in their study, age was found to be an independent variable for depression in the multivariate regression analysis. It is thought that reasons such as decreasing expectations from life with age, increase in chronic diseases and their adverse effects on daily life, increase in uncertainties and losses would cause the level of depression to increase.

Being in the ICU is a stressful experience for patients. Psychological well-being is affected due to many factors such as the criticality of the patient's life, painful invasive interventions, inactivity, lack of privacy, disruption of sleep patterns, separation from loved ones and lack of adequate information.

It is expected that patients' anxiety and depression levels would increase depending on the duration and frequency of exposure to these factors in ICU.

In our study, a significant increase was observed in the patients' anxiety and depression scores as the length of stay in the ICU increased. Additionally, in the univariate regression analysis performed to identify independent predictors of ICU anxiety, the duration of ICU stay was found to be an independent predictor of anxiety. Similarly, in the study conducted by Eryiğit and Aydın,[18] depression levels of patients increased, as the duration of stay in the ICU increased. The study by Bryant et al.[19] showed that depression had a positive relationship with a longer stay in the ICU.

The symptoms experienced by AMI patients depending on their hemodynamic status and respiratory distress due to lung congestion in patients other than Killip Class I may cause fear of death and increase the development of anxiety in these patients. In particular, in patients with Killip Class III-IV, respiratory support and hemodynamic support may be required, and these factors may also predispose to the development of anxiety. In our study, with the influence of these possible factors, anxiety development was found to be significantly higher in patients other than Killip Class I. Additionally, being in Killip Class II-IV was found to be an independent predictor for anxiety by univariate and multivariate regression analysis.

There is no study in the literature on the effect of the Killip class on the development of anxiety. Ekici[16] investigated the relationship between CAD severity and anxiety levels and found that as the severity of CAD determined by Gensini and SYNTAX scores increased, anxiety scores as determined by HADS increased. However, Makca[20] found no significant difference in anxiety and depression scores between patients with non-critical coronary artery stenosis and critical coronary artery stenosis as evidenced by angiography findings.

In our study, we observed a negative significant relationship between the patients' calcium, total cholesterol, hemoglobin and hematocrit values and their depression scores, while there was a positive significant relationship between the troponin level and the depression scores. Ekici[16] also found that there was a significant negative relationship between hemoglobin and hematocrit values and the HADS depression scale.

The main limitation to the present study is that the total number of patients and the number of those in Killip Class II-IV are relatively low. To support our study results, further larger-scale, prospective studies are needed regarding the predictive value of the Killip class in the development of anxiety in AMI patients.

In conclusion, Killip classification is an independent predictor of anxiety in AMI patients.

Since patients with AMI, particularly those who are in Killip Class II-IV, are in the risk group for anxiety, it is of utmost importance to evaluate the anxiety status of these patients as soon as possible and to identify and reduce the affecting factors in order to facilitate adaptation to the disease and positively affect the treatment process.

Data Sharing Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Author Contributions: Idea, design, data collection and writing the article: N.Ç.; Data analysis and literature review: N.Ş.; Design and data collection: S.G.; Data analysis and data collection: E.E.; Design,data collection and control: G.İ.A.; Idea, supervision and critical review: O.Ş.

Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding: The authors received no financial support for the research and/or authorship of this article.

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