Vol 8, No 2 (2023)
Original article
Published online: 2023-06-06

open access

Page views 1249
Article views/downloads 320
Get Citation

Connect on Social Media

Connect on Social Media

The predictive value of complete blood count-derived indices for major adverse cardiovascular events in MINOCA patients at 5-year follow-up

Patryk Buller1, Adam Kern2, Maciej Tyczyński3, Wojciech Rosiak4, Wojciech Figatowski1, Robert J. Gil5, Jacek Bil3
Medical Research Journal 2023;8(2):128-134.

Abstract

Introduction: The authors analysed the potential of red blood cell and platelet indices such as red cell distribution width (RDW), mean corpuscular volume (MCV), and mean platelet volume (MPV) as predicting factors in myocardial infarction with non-obstructive coronary arteries (MINOCA) patients of 5-year outcomes.

Material and methods: Between 2010–2015 were identified 112 patients who had final MINOCA diagnosis and available laboratory findings. The primary endpoint was the 5-year major adverse cardiovascular events rate, defined as cardiac death, myocardial infarction, or hospitalization due to angina.

Results: Only RDW had a significant impact on long-term outcomes. 93 (83%) patients had RDW ≤ 14.5 (group 1), and 19 (17%) patients had RDW > 14.5 (group 2). The mean RDW value was 13.58 ± 1.11%. In group 1 and group 2, mean RDW values were 13.18 ± 0.55%, and 15.54 ± 1.06% (p < 0.001), respectively. Patients with abnormal RDW values (group 2) characterized lower value of left ventricular eject fraction (60 ± 8% vs. 53 ± 13%, p = 0.024), and higher NT-proBNP values (3,170 ± 5,285 pg/mL vs. 6,200 ± 4,223 pg/mL, p = 0.013) as well as troponin levels (501–2500 ng/mL: 31% vs. 53%, p = 0.02). A statistically significant difference was observed only for all-cause death. All-cause death rates for no RDW ≤ 14.5% vs. RDW > 14.5% were 2.2% vs. 21.1% (HR 5.09, 95% CI 1.03–25.2, p = 0.046), respectively.

Conclusions: RDW was significantly associated with the increased risk of all-cause mortality in MINOCA patients at 5 years.

ORIGINAL ARTICLE

Medical Research Journal 2023;

Volume 8, Number 2, 128–134

10.5603/MRJ.a2023.0023

Copyright © 2023 Via Medica

ISSN 2451-2591

e-ISSN 2451-4101

The predictive value of complete blood count-derived indices for major adverse cardiovascular events in MINOCA patients at 5-year follow-up

Patryk Buller1Adam Kern2Maciej Tyczyński3Wojciech Rosiak4Włodzimierz Figatowski1Robert J. Gil5Jacek Bil3
1Department of Cardiology, Provincial Integrated Hospital, Plock, Poland
2Department of Cardiology and Internal Medicine, University of Warmia and Mazury, Olsztyn, Poland
3Department of Invasive Cardiology, Centre of Postgraduate Medical Education, Warsaw, Poland
4Department of Internal Medicine, Independent Public Complex of Healthcare Institutions, Zuromin, Poland
5Department of Cardiology, State Medical Institute of the Ministry of Interior, Warsaw, Poland

Corresponding author:

Jacek Bil, MD, PhD, FESCDepartment of Invasive Cardiology, Centre of Postgraduate Medical Education, 137 Woloska St., 02–507 Warsaw, Poland; e-mail: biljacek@gmail.com

ABSTRACT

Introduction: The authors analysed the potential of red blood cell and platelet indices such as red cell distribution width (RDW), mean corpuscular volume (MCV), and mean platelet volume (MPV) as predicting factors in myocardial infarction with non-obstructive coronary arteries (MINOCA) patients of 5-year outcomes.

Material and methods: Between 2010–2015 were identified 112 patients who had final MINOCA diagnosis and available laboratory findings. The primary endpoint was the 5-year major adverse cardiovascular events rate, defined as cardiac death, myocardial infarction, or hospitalization due to angina.

Results: Only RDW had a significant impact on long-term outcomes. 93 (83%) patients had RDW ≤ 14.5 (group 1), and 19 (17%) patients had RDW > 14.5 (group 2). The mean RDW value was 13.58 ± 1.11%. In group 1 and group 2, mean RDW values were 13.18 ± 0.55%, and 15.54 ± 1.06% (p < 0.001), respectively. Patients with abnormal RDW values (group 2) characterized lower value of left ventricular eject fraction (60 ± 8% vs. 53 ± 13%, p = 0.024), and higher NT-proBNP values (3,170 ± 5,285 pg/mL vs. 6,200 ± 4,223 pg/mL, p = 0.013) as well as troponin levels (501–2500 ng/mL: 31% vs. 53%, p = 0.02). A statistically significant difference was observed only for all-cause death. All-cause death rates for no RDW ≤ 14.5% vs. RDW > 14.5% were 2.2% vs. 21.1% (HR 5.09, 95% CI 1.03–25.2, p = 0.046), respectively.

Conclusions: RDW was significantly associated with the increased risk of all-cause mortality in MINOCA patients at 5 years.

Key words: acetylcholine, chronic coronary syndrome, clinical outcomes, INOCA

Med Res J 2023; 8 (2): 128–134

Introduction

Myocardial infarction with the non-obstructive coronary arteries (MINOCA) is a heterogeneous disorder [1, 2]. Recently, it has become acknowledged that MINOCA is not a rare entity, and it affects 515% of patients presenting with acute MI [1, 3–5]. However, MINOCA was deemed as a non-serious disorder with favourable outcomes; nevertheless, from very recently, it has been perceived that MINOCA is associated with a worse prognosis and higher incidence of future cardiovascular events than the general population [6–8]. For example, at 4 years, Lindahl et al. reported a major adverse cardiovascular event (MACE) rate of 23.9%, an all-cause death rate of 13.4%, MI of 7.1%, and heart failure hospitalization of 6.4% [9]. As a result, a comprehensive understanding of MINOCA-evoking factors is crucial to introduce personalized management that could decrease mortality as well as improve the quality of life [10].

In previous research studies, the red blood cell distribution width (RDW) and platelet distribution width (PDW) were reported to be independent negative predictors of many cardiovascular diseases (CVD) [11–14]. The exact underlying mechanisms still must be elucidated. However, some research papers highlighted the interaction between endothelium with impaired function, oxidative stress, and inflammatory response [1, 15, 16].

At the same time, few studies investigated the role of complete blood count-derived markers in patients with ischaemia and non-obstructive coronary arteries. Research studies were identified assessing the role of RDW in cardiac syndrome X [17], vasospastic angina [18], or slow flow phenomenon [19]. In addition, Lee et al. disclosed the positive correlation between neutrophil-to-lymphocyte ratio and index of microcirculatory resistance in ST-segment elevation MI patients undergoing primary percutaneous coronary intervention [20].

Earlier, it was shown that PDW and RDW correlated with coronary microcirculation spasms in patients undergoing provocative acetylcholine tests. The female sex (odds ratio [OR] = 1.199), PDW (OR = 2.891), and RDW (OR = 1.567) were identified as the independent risk factors for coronary microcirculation spasm diagnosis [21]. To the authors’ knowledge, there is also no data on the association between complete blood count indices and long-term outcomes in MINOCA patients. The present study analyses various red blood cell and platelet indices such as RDW, mean corpuscular volume (MCV), and mean platelet volume (MPV), assessing their potential as predicting factors in MINOCA patients at 5-year outcomes.

Material and methods

Study design and participants

It was a retrospective, non-interventional study. Initially, all patients undergoing coronary angiography due to MI were identified. Then, only patients with coronary angiography with non-obstructive coronary arteries (lesions < 50% of diameter stenosis) and with MINOCA as a final diagnosis were separated. In the final analysis, patients for whom blood count recordings were available were included.

Data collection

Demographic, clinical, periprocedural, and laboratory data from the hospital database were collected. Retrieved was information on arterial hypertension, dyslipidaemia, diabetes mellitus, peripheral artery disease, atrial fibrillation, chronic kidney disease (defined as eGFR < 60 mL/min/1.73 m2), prior percutaneous coronary intervention (PCI), prior MI, prior coronary artery bypass grafting, and clinical data associated with MI: type, disease advancement, treatment strategy, and periprocedural complications. Additionally, data on echocardiographic parameters (left ventricular ejection fraction) and laboratory findings assessed at admission were obtained. The upper reference limits were as follows: RDW 14.5%, MCV 92 fL, and MPV — 9 fL. Also, information on medications at discharge was gathered.

Study endpoints

The primary study endpoint was the 5-year rate of major cardiovascular adverse events (MACE) defined as joined rates of cardiac death, MI, and recurrent hospitalization due to angina. The secondary endpoints included all-cause death, cardiac death, MI, and recurrent hospitalization due to angina rates at 5-year follow-up.

Statistical methods

Initially, in the multivariable Cox regression model, it was checked if any of these values (RDW, MCV, MPV) according to the upper limit of the reference range as the threshold impacted the study endpoints. Only RDW had a significant impact, and further analyses were performed in subgroups: normal RDW (≤ 14.5%) vs. increased RDW value (> 14.5%).

Descriptive statistics were presented: mean, standard deviation, minimum, 25% centile, median, 75% centile, and maximum for continuous variables; count and per cent for categorical variables. Pearson’s Chi-squared test or Fisher’s exact test was performed to compare categorical variables between two groups (e.g., normal RDW vs. increased RDW value). Fisher’s exact test was used when at least one of the subgroups had count = 0. Wilcoxon rank sum test was performed to compare continuous variables between two groups (e.g., normal RDW vs. increased RDW value). P-value << 0.05 was statistically significant. Kaplan-Meier estimators with a 95% confidence interval (CI) were calculated to compare 5-year survival curves for various endpoints between groups (e.g., normal RDW vs. increased RDW value). If a given endpoint occurred for a particular patient more than once in a 5-year follow-up period, then survival time was assumed as the time to the first occurrence of this endpoint. Notably, in the case of MACE (a composite endpoint), survival time was assumed as the time to the first occurrence of either cardiac death, myocardial infarction, or angina pectoris hospitalization. Statistical analyses were performed using R software version 4.2.1 (2022-06--23 ucrt) “Funny-Looking Kid” Copyright (C) 2022 The R Foundation for Statistical Computing Platform: x86_64-w64-mingw32/x64 (64-bit).

Table 1. Analysis of complete blood count-derived indices (multivariable Cox regression)

Characteristic

Hazard ratio [HR]

95% Confidence interval [CI]

P-value

All-cause death

RDW

5.09

1.03–25.2

0.046

MPV

0.67

0.28–1.64

0.384

MCV

0.80

0.15–4.38

0.799

Cardiac death

RDW

0.32

0.01–10.7

0.523

MPV

0.70

0.08–5.96

0.746

MCV

0.99

0.70–1.39

0.940

Myocardial infarction

RDW

1.13

0.46–1.56

0.6

MPV

1.13

0.51–2.53

0.763

MCV

0.97

0.82–1.16

0.766

Hospitalization due to angina

RDW

1.53

0.32–7.36

0.597

MPV

1.38

0.86–2.22

0.183

MCV

0.98

0.87–1.11

0.773

MACE

RDW

1.73

0.67–4.32

0.2

MPV

1.40

0.92–2.14

0.119

MCV

0.90

0.26–3.07

0.866

Results

Between 20102015 were identified 3171 coronary angiography procedures performed due to acute coronary syndrome, from which 153 had working MINOCA diagnosis, and the final diagnosis of MINOCA was ascribed to 112 (5.8%) patients. All patients had required laboratory results available.

Figure 1. Study flowchart
ACS acute coronary syndrome; MINOCA myocardial infarction with non-obstructive coronary arteries; NSTEMI non-ST-elevation myocardial infarction; RDW red cell distribution width; STEMI ST-elevation myocardial infarction
Analysis of complete blood count-derived indices

The authors performed Cox regression analysis, checking the influence of RDW, MPV, and MCV values (Tab. 1). As a result, only RDW as having a significant impact on long-term outcomes were identified. Further, the analysis for patients with RDW14.5% (group 1) and RDW > 14.5% (group 2) was presented.

Table 2. Baseline characteristics

Parameter

Group 1

N = 93

Group 2

N = 19

P-value

Females

55 (59%)

12 (63%)

0.7

Age [years]

62 ± 14

66 ± 16

0.3

Body mass index [kg/m2]

27.5 ± 5.0

30.0 ± 8.7

0.2

Myocardial infarction type at presentation

NSTEMI

12 (13%)

5 (26%)

0.3

STEMI

80 (86%)

14 (74%)

Arterial hypertension

49 (53%)

10 (53%)

> 0.9

Diabetes type 2

12 (13%)

3 (16%)

0.7

Dyslipidaemia

27 (29%)

1 (5.3%)

0.039

Chronic kidney disease

3 (3.2%)

1 (5.3%)

0.5

Atrial fibrillation

19 (20%)

6 (32%)

0.4

Peripheral artery disease

1 (1.1%)

0

> 0.9

Smoking

10 (11%)

3 (16%)

0.5

LVEF [%]

60 ± 8

53 ± 13

0.024

Coronary lesions

No lesions

46 (49%)

5 (26%)

0.2

< 30%

31 (33%)

10 (53%)

30–50%

16 (18%)

4 (21%)

Baseline characteristics

All patients had required laboratory results available, and among them, 93 (83%) had RDW14.5 (group 1), and 19 (17%) patients had RDW > 14.5 (group 2) (Fig. 1). The mean RDW value was 13.58 ± 1.11% (min. 12.10%, max. 18.8%). In group 1 and group 2, mean RDW values were 13.18 ± 0.55% (min. 12.10%, max. 14.40), and 15.54 ± 1.06% (min. 14.70, max. 18.80; p < 0.001), respectively.

Baseline characteristics are presented in Table 2. Patients did not differ in terms of sex (females: group 1 vs. group 2: 59% vs. 63%, p = 0.7) or age (62 ± 14 years vs. 66 ± 16 years, p = 0.3). Patients with abnormal RDW values (group 2) characterized the statistically significant lower risk of dyslipidemia (29% vs. 5.3%, p = 0.039) and lower value of left ventricular ejection fraction (60 ± 8% vs. 53 ± 13%, p = 0.024). Table 3 presents laboratory findings at admission. Group 2 patients characterized higher NT-proBNP values (3,170 ± 5,285 pg/mL vs. 6,200 ± 4,223 pg/mL, p = 0.013) and higher troponin levels (5012500 ng/mL 31% vs. 53%, p = 0.02).

Management at discharge

All included patients were discharged. Table 4 presents medications prescribed at discharge. All patients received similar treatment.

Outcomes at five years

Survival rates at five years are presented in Table 5, and Kaplan-Meier curves for all-cause death are shown in Figure 2. A statistically significant difference was observed only for all-cause death. All-cause death rates for no RDW14.5% vs. RDW > 14.5% were 2.2% vs. 21.1% (HR 5.09, 95% CI 1.0325.2, p = 0.046), respectively.

Discussion

To the authors’ knowledge, this study is the first to verify the predictive value of complete blood count indices in MINOCA patients in the long-term follow-up. RDW was significantly associated with all-cause death at five years.

The RDW is a parameter characterizing erythrocyte volume variations (i.e., anisocytosis) and is readily available in a complete blood count result [22]. Several research papers reported that RDW was linked with CVDs and increased RDW values were predicting factors of poor outcomes not only in patients with ischaemic heart disease but also in other populations such as subjects with arterial hypertension [23], hypertrophic cardiomyopathy [24], undergoing carotid endarterectomy [25], congenital heart disease [26] or aortoiliac disease [27].

But coming back to RDW, it is definitely a predictor of poor outcomes in patients with obstructive coronary artery disease. Dai et al. showed that RDW was an independent predictor of MI type 4a [28]. Zhang et al. showed that RDW was linked with increased risk of MACE (HR 1.75), all-cause mortality (HR 1.58), and any revascularization (HR 2.10) [29] at long-term follow-up. In the research by Wu et al., RDW was an independent predictor of cardiac death (HR 1.33) but not all-cause mortality or MACE at 3 years [30]. The interesting concept was developed by Xiao et al. [31], who proposed to measure the change of RDW (RDW) before PCI and 16 weeks after PCI. The RDW showed the potential to predict MACE. The range of HR values was slightly lower than in the current study, i.e., HR 5.09 for all-cause mortality at 5 years. However, this can be explained by the fact that the authors assessed the population with MI and had the most extended follow-up. In patients undergoing PCI, also other factors had a substantial impact, such as PDW in subjects undergoing PCI within coronary bifurcation lesions [14].

Table 3. Laboratory findings at admission

Parameter

Group 1

N = 93

Group 2

N = 19

P-value

White blood cells [109/L]

9.5 ± 3.8

11.4 ± 4.9

0.063

Haemoglobin [g/dL]

13.97 ± 1.37

13.23 ± 1.81

0.12

Red blood cells [1012/L]

4.58 ± 0.45

4.38 ± 0.61

0.2

Platelets [109/L]

244 ± 65

278 ± 128

0.4

RDW [fL]

13.18 ± 0.55

15.54 ± 1.06

< 0.001

MPV [fL]

8.32 ± 1.06

8.59 ± 1.34

0.4

MCV [fL]

90.6 ± 4.7

92.0 ± 9.8

0.6

Glucose [mmol/L]

7.31 ± 2.42

8.02 ± 2.81

0.3

HbA1c [%]

5.91 ± 0.41

5.90 ± 0.28

0.8

NT-proBNP [pg/mL]

3.170 ± 5.285

6.200 ± 4.223

0.013

C-reactive protein

1.9 ± 2.8

10.3 ± 20.5

0.7

AST [U/L]

40 (29–59)

49 (31–56)

0.8

ALT [U/L]

32 (26–50)

27 (15–68)

0.7

Total cholesterol [mmol/L]

4.78 ± 1.14

4.81 ± 0.88

0.9

HDL [mmol/L]

1.55 ± 0.55

1.81 ± 1.12

0.9

LDL [mmol/L]

2.62 ± 1.05

2.36 ± 0.99

0.4

Triglycerides [mmol/L]

1.37 ± 0.58

1.40 ± 0.72

0.8

Creatine [µmol/L]

84 ± 24

97 ± 55

0.8

TSH [µU/mL]

1.49 ± 1.13

1.96 ± 2.40

0.7

Maximal troponin T [ng/mL]

0–500

59 (63%)

8 (42%)

0.02

501–2500

29 (31%)

10 (53%)

2501–10000

5 (5.4%)

1 (5.3%)

10000+

0 (0%)

0 (0%)

Some studies also showed that patients with increased RDW value characterized unfavourable prognosis after acute MI (OR 2.2 for MACE) [32]. This was also confirmed in other studies [33–35]. In one of these studies, similar to the current one, the association between increased RDW value and increased NT-proBNP was confirmed [33]. Interestingly, subanalysis from the ODYSSEY OUTCOMES study showed that despite heavy treatment of dyslipidaemia with alirocumab, RDW remained an independent predictor of MACE after acute coronary syndrome [36].

Table 4. Medications at discharge

Parameter

Group 1

N = 93

Group 2

N = 19

P-value

ASA

87 (93.5%)

18 (94.7%)

> 0.9

Clopidogrel

68 (73.1%)

13 (68.4%)

0.6

Beta-blocker

73 (78.5%)

15 (78.9%)

> 0.9

Ca-blocker

22 (23.6%)

6 (31.6%)

0.6

ACE inhibitor

66 (70.9%)

15 (78.9%)

0.5

Angiotensin receptor blocker

5 (5.3%)

0

0.6

Diuretic

19 (20.4%)

6 (31.6%)

0.4

Trimetazidine

2 (2.2%)

0

> 0.9

Nitrates

50 (53.7%)

11 (57.9%)

0.8

Vitamin K antagonist

10 (10.8%)

3 (15.8%)

0.7

Novel oral anticoagulant

3 (3.3%)

1 (5.3%)

0.5

Statin

84 (90.3%)

17 (89.5%)

0.7

The RDW threshold differed in various studies for outcomes in patients with ischaemic heart disease and/or hypertension. It ranged from 12.6% to 14.8% [23, 28, 30, 34, 35]. In the present study, the authors applied the threshold of 14.5% as this was the upper reference limit in the laboratory. However, when the authors also applied the median (13.2%) as the threshold, it did not impact long-term outcomes (data not shown).

Figure 2. Kaplan-Meier curves for all-cause death at 5 years for MINOCA patients with RDW14.5% and RDW > 14.5%; RDW red blood cell distribution width

In coronary microcirculation dysfunction, often is observed coronary slow flow (CSF) phenomenon, defined as a delayed distal coronary artery opacification without significant stenosis on coronary angiography. The CSF mechanism remains somewhat unclear, although an inflammatory state, endothelial dysfunction, or hampered rheological blood properties play an essential part [37]. In a large patient population of 17,315 cases, Akpinar et al. [19] reported that increased RDW and PDW values correlated with microvascular blood flow resistance. Nevertheless, in the authors’ previous research, it was not observed that CSF had a negative impact on outcomes in MINOCA patients at 5 years [38].

Ultimately, the white blood cell count issue should be raised in our population. In group 2 with RDW > 14.5%, was observed an increased white blood cell value above the upper reference level. This observation and an elevated RDW value might suggest that a subclinical inflammatory condition may be one of the potential underlying mechanisms of poor outcomes and may predict ischaemic events in the coronary microcirculation. As a consequence, in the follow-up, one can observe a relatively benign situation as recurrent chest pain diminishing quality of life. Nevertheless, acute coronary syndromes or malignant ventricular arrhythmias can also be observed and be responsible for death cases in MINOCA patients at long-term follow-up.

Table 5. Study population 5-year outcomes

Parameter

Group 1

N = 93

Group 2

N = 19

HR

95% CI

P-value

All-cause death

2 (2.2%)

4 (21.1%)

5.09

1.03–25.2

0.046

Cardiac death

1 (1.1%)

0

0.32

0.01–10.7

0.523

Myocardial infarction

3 (3.2%)

1 (5.3%)

1.13

0.46–1.56

0.6

Percutaneous intervention

1 (1.1%)

1 (5.3%)

1.23

0.84–2.34

0.4

Hospitalization due to angina

6 (6.5%)

3 (15.8%)

1.53

0.32–7.36

0.597

MACE

9 (9.7%)

4 (21.1%)

1.73

0.67–4.32

0.2

Study limitations

This study has several limitations. Firstly, this is a single-centre retrospective study with a relatively small size, and the number of some outcomes is small. Secondly, the indices taken into consideration were somewhat limited, with only three. Finally, all indices were measured only at one point, not repeated during the hospital or the follow-up period. Therefore, this study’s findings require confirmation in a multicentre, prospective, large sample size study with more inflammatory biomarkers and dynamic markers changes to validate these findings and elucidate more comprehensively the role of inflammatory response in MACE predicting.

Conclusions

To the best of the authors’ knowledge, this study is the first to investigate the predictive value of complete blood count indices in MINOCA patients in long-term follow-up. RDW was significantly associated with all-cause death at five years.

Conflict of interest: None.
Funding: None.
Ethical approval: The study protocol was reviewed and approved by the Institutional Review Board (or Ethics Committee) of the District Physician Chamber in Plock (No 1/2020 of 20.11.2020). Patient consent was waived due to the retrospective nature of the study.

References

  1. Bil J, Pietraszek N, Pawlowski T, et al. Advances in mechanisms and treatment options of MINOCA caused by vasospasm or microcirculation dysfunction. Curr Pharm Des. 2018; 24(4): 517531, doi: 10.2174/1381612824666180108121253, indexed in Pubmed: 29308736.
  2. Yildiz M, Ashokprabhu N, Shewale A, et al. Myocardial infarction with non-obstructive coronary arteries (MINOCA). Front Cardiovasc Med. 2022; 9: 1032436, doi: 10.3389/fcvm.2022.1032436, indexed in Pubmed: 36457805.
  3. Bossard M, Gao P, Boden W, et al. Antiplatelet therapy in patients with myocardial infarction without obstructive coronary artery disease. Heart. 2021; 107(21): 17391747, doi: 10.1136/heartjnl-2020-318045, indexed in Pubmed: 33504513.
  4. Schmitz K, Groth N, Mullvain R, et al. Prevalence, clinical factors, and outcomes associated with myocardial infarction with nonobstructive coronary artery. Crit Pathw Cardiol. 2021; 20(2): 108113, doi: 10.1097/HPC.0000000000000249, indexed in Pubmed: 33337728.
  5. Gasior P, Desperak A, Gierlotka M, et al. Clinical characteristics, treatments, and outcomes of patients with myocardial infarction with non-obstructive coronary arteries (MINOCA): results from a multicenter national registry. J Clin Med. 2020; 9(9), doi: 10.3390/jcm9092779, indexed in Pubmed: 32867273.
  6. Bil J, Kern A, Bujak K, et al. Clinical characteristics and 12-month outcomes in MINOCA patients before and during the COVID-19 pandemic. Pol Arch Intern Med. 2023 [Epub ahead of print], doi: 10.20452/pamw.16405, indexed in Pubmed: 36602860.
  7. Bil J, MoŻeŃska O, Segiet-ŚwiĘcicka A, et al. Revisiting the use of the provocative acetylcholine test in patients with chest pain and nonobstructive coronary arteries: A five-year follow-up of the AChPOL registry, with special focus on patients with MINOCA. Transl Res. 2021; 231: 6475, doi: 10.1016/j.trsl.2020.11.009, indexed in Pubmed: 33232803.
  8. Dreyer RP, Tavella R, Curtis JP, et al. Myocardial infarction with non-obstructive coronary arteries as compared with myocardial infarction and obstructive coronary disease: outcomes in a Medicare population. Eur Heart J. 2020; 41(7): 870878, doi: 10.1093/eurheartj/ehz403, indexed in Pubmed: 31222249.
  9. Lindahl B, Baron T, Erlinge D, et al. Medical therapy for secondary prevention and long-term outcome in patients with myocardial infarction with nonobstructive coronary artery disease. Circulation. 2017; 135(16): 14811489, doi: 10.1161/CIRCULATIONAHA.116.026336, indexed in Pubmed: 28179398.
  10. Gulati M, Khan N, George M, et al. Ischemia with no obstructive coronary artery disease (INOCA): A patient self-report quality of life survey from INOCA international. Int J Cardiol. 2023; 371: 2839, doi: 10.1016/j.ijcard.2022.09.047, indexed in Pubmed: 36162521.
  11. Arbel Y, Shacham Y, Finkelstein A, et al. Red blood cell distribution width (RDW) and long-term survival in patients with ST elevation myocardial infarction. Thromb Res. 2014; 134(5): 976979, doi: 10.1016/j.thromres.2014.08.016, indexed in Pubmed: 25213710.
  12. Hou H, Sun T, Li C, et al. An overall and dose-response meta-analysis of red blood cell distribution width and CVD outcomes. Sci Rep. 2017; 7: 43420, doi: 10.1038/srep43420 , indexed in Pubmed: 28233844.
  13. Su C, Liao LZ, Song Y, et al. The role of red blood cell distribution width in mortality and cardiovascular risk among patients with coronary artery diseases: a systematic review and meta-analysis. J Thorac Dis. 2014; 6(10): 14291440, doi: 10.3978/j.issn.2072-1439.2014.09.10, indexed in Pubmed: 25364520.
  14. Kern A, Gil RJ, Bojko K, et al. Platelet distribution width as the prognostic marker in coronary bifurcation treatment. Eur J Clin Invest. 2017; 47(7): 524530, doi: 10.1111/eci.12773, indexed in Pubmed: 28555728.
  15. Sabe SA, Feng J, Sellke FW, et al. Mechanisms and clinical implications of endothelium-dependent vasomotor dysfunction in coronary microvasculature. Am J Physiol Heart Circ Physiol. 2022; 322(5): H819H841, doi: 10.1152/ajpheart.00603.2021, indexed in Pubmed: 35333122.
  16. Sucato V, Corrado E, Manno G, et al. Biomarkers of coronary microvascular dysfunction in patients with microvascular angina: a narrative review. Angiology. 2022; 73(5): 395406, doi: 10.1177/00033197211034267, indexed in Pubmed: 34338554.
  17. Demirkol S, Balta S, Celik T, et al. Assessment of the relationship between red cell distribution width and cardiac syndrome X. Kardiol Pol. 2013; 71(5): 480484, doi: 10.5603/KP.2013.0094, indexed in Pubmed: 23788088.
  18. Jung MH, Shin DIl, Choi IkJ, et al. Association between the red cell distribution width and vasospastic angina in Korean patients. Yonsei Med J. 2016; 57(3): 614620, doi: 10.3349/ymj.2016.57.3.614, indexed in Pubmed: 26996559.
  19. Akpinar I, Sayin MR, Gursoy YC, et al. Plateletcrit and red cell distribution width are independent predictors of the slow coronary flow phenomenon. J Cardiol. 2014; 63(2): 112118, doi: 10.1016/j.jjcc.2013.07.010, indexed in Pubmed: 24012331.
  20. Lee MJ, Park SD, Kwon SW, et al. Relation between neutrophil-to-lymphocyte ratio and index of microcirculatory resistance in patients with st-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. Am J Cardiol. 2016; 118(9): 13231328, doi: 10.1016/j.amjcard.2016.07.072, indexed in Pubmed: 27600462.
  21. Bil J, Pietraszek N, Gil RJ, et al. Complete blood count-derived indices as prognostic factors of 5-year outcomes in patients with confirmed coronary microvascular spasm. Front Cardiovasc Med. 2022; 9: 933374, doi: 10.3389/fcvm.2022.933374, indexed in Pubmed: 35845050.
  22. Karakas MS, Korucuk N, Tosun V, et al. Red cell distribution width and neutrophil-to-lymphocyte ratio predict left ventricular dysfunction in acute anterior ST-segment elevation myocardial infarction. J Saudi Heart Assoc. 2016; 28(3): 152158, doi: 10.1016/j.jsha.2015.07.001, indexed in Pubmed: 27358532.
  23. Uzun F, Guner A, Pusuroglu H, et al. Association of red blood cell distribution width, systemic-immune-inflammation index and poor cardiovascular outcomes in patients with newly diagnosed hypertension. Clin Exp Hypertens. 2022; 44(6): 530538, doi: 10.1080/10641963.2022.2079668, indexed in Pubmed: 35642501.
  24. Li J, Gao W, Liu J, et al. Red blood cell distribution width and maximum left ventricular wall thickness predict poor outcomes in patients with hypertrophic cardiomyopathy. Echocardiography. 2022; 39(2): 278285, doi: 10.1111/echo.15303, indexed in Pubmed: 35066909.
  25. Duarte-Gamas L, Pereira-Neves A, Jácome F, et al. Red blood cell distribution width as a 5-year prognostic marker in patients submitted to carotid endarterectomy. Cerebrovasc Dis Extra. 2020 [Epub ahead of print]; 10(3): 181192, doi: 10.1159/000512587, indexed in Pubmed: 33326971.
  26. Martínez-Quintana E, Estupiñán-León H, Riaño-Ruiz M, et al. Red blood cell distribution width in addition to N-terminal prohormone of B-type natriuretic peptide concentration improves assessment of risk of cardiovascular events in adult patients with congenital heart disease. Arch Cardiovasc Dis. 2020; 113(10): 607616, doi: 10.1016/j.acvd.2020.05.019, indexed in Pubmed: 33039325.
  27. Vieira-Cardoso N, Pereira-Neves A, Fragão-Marques M, et al. Red blood cell distribution width as a predictor of cardiovascular outcomes in extensive aortoiliac disease. J Cardiovasc Surg (Torino). 2023; 64(1): 4857, doi: 10.23736/S0021-9509.22.12210-X, indexed in Pubmed: 36168948.
  28. Dai C, Chen Z, Qian J, et al. Red cell distribution width as a marker of periprocedural myocardial infarction in patients with elective percutaneous coronary intervention. J Cardiovasc Transl Res. 2021; 14(3): 449456, doi: 10.1007/s12265-020-10073-w, indexed in Pubmed: 33029742.
  29. Zhang B, Xu Y, Huang X, et al. Red blood cell distribution width: a risk factor for prognosis in patients with ischemic cardiomyopathy after percutaneous coronary intervention. J Clin Med. 2023; 12(4), doi: 10.3390/jcm12041584, indexed in Pubmed: 36836116.
  30. Wu TT, Zheng YY, Hou XG, et al. Red blood cell distribution width as long-term prognostic markers in patients with coronary artery disease undergoing percutaneous coronary intervention. Lipids Health Dis. 2019; 18(1): 140, doi: 10.1186/s12944-019-1082-8, indexed in Pubmed: 31186012.
  31. Xiao Q, Yan D, Qin J, et al. Dynamic changes in red cell distribution width can predict major adverse cardiovascular events after PCI in patients with unstable angina pectoris: a retrospective cohort study. Dis Markers. 2022; 2022: 2735717, doi: 10.1155/2022/2735717, indexed in Pubmed: 35722627.
  32. Markovic Bo, Brizic I, Mikulic I. The significance of red cell distribution width and homocysteine values in STEMI patients undergoing PCI in the population of Bosnia and Herzegovina. Eur Rev Med Pharmacol Sci. 2021; 25(10): 37913797, doi: 10.26355/eurrev_202105_25946, indexed in Pubmed: 34109587.
  33. Pan R. Relationship of red cell volume distribution width and n-terminal pro-brain natriuretic peptide with severity and prognosis of patients with acute coronary syndrome receiving percutaneous coronary intervention. Clin Lab. 2020; 66(4), doi: 10.7754/Clin.Lab.2019.190513, indexed in Pubmed: 32255302.
  34. Machado GP, de Araujo GN, Carpes CK, et al. Long-term pattern of red cell distribution width in patients with st-elevation myocardial infarction undergoing primary percutaneous coronary intervention. Crit Pathw Cardiol. 2020; 19(1): 4348, doi: 10.1097/HPC.0000000000000196, indexed in Pubmed: 31478946.
  35. Turcato G, Serafini V, Dilda A, et al. Red blood cell distribution width independently predicts medium-term mortality and major adverse cardiac events after an acute coronary syndrome. Ann Transl Med. 2016; 4(13): 254, doi: 10.21037/atm.2016.06.35, indexed in Pubmed: 27500155.
  36. Moriarty PM, Steg PG, McGinniss J, et al. ODYSSEY OUTCOMES Investigators. Relation of red blood cell distribution width to risk of major adverse cardiovascular events, death, and effect of alirocumab after acute coronary syndromes. J Clin Lipidol. 2022; 16: 747756.
  37. Yucel H, Ozaydin M, Dogan A, et al. Evaluation of plasma oxidative status in patients with slow coronary flow. Kardiol Pol. 2013; 71(6): 588594, doi: 10.5603/KP.2013.0122, indexed in Pubmed: 23797431.
  38. Buller P, Kern A, Tyczynski M, et al. Coronary slow flow is not an adverse prognostic factor in MINOCA patients in the 5-year follow-up. Med Res J (in press). 2023.