Characteristics That Affect the Long-term Clinical Outcome and Stroke Recurrence in Ischaemic Stroke Patients With Basilar Artery Atherosclerosis

doi:10.21203/rs.3.rs-3867836/v1

İntroduction: Posterior circulation stroke differs from anterior circulation stroke in etiopathogenesis. Studies have shown that the most common stroke aetiology in posterior circulation stroke is ischemic stroke due to large vessel atherosclerosis. However, even under aggressive medical treatment, the risk of recurrent ischemic stroke in ischemic stroke due to intracranial atherosclerotic stenosis remains high. This study aims to obtain the rate of atherosclerotic disease of the BA in our ischemic stroke population, to determine its symptomatology, and to determine the factors affecting clinical outcome and ischaemic stroke recurrence in the symptomatic group.

Material method: we included 107 patients who were diagnosed with acute ischemic stroke with basilar artery stenosis.

Results

According to the results of our study, the degree of stenosis in atherosclerotic stenosis of the symptomatic BA was found to be an independent risk factor for stroke recurrence. Independent risk factors for unfavourable clinical outcomes in these patients were determined as female gender, stenosis being in the proximal segment, stroke mechanism being from artery to artery embolism, and congestive heart failure.

Discussion

The most striking result of our study is that clinical outcome was found to be closely related to the female gender, the stroke mechanism being artery-to-artery embolism, and the stenosis is in the proximal segment. If stroke mechanisms were evaluated more clearly, it would likely help provide individualized treatments.

Health sciences/Neurology/Neurological disorders/Stroke

Health sciences/Risk factors

Health sciences/Neurology/Neurological disorders/Cerebrovascular disorders/Stroke

intracranial atherosclerotic disease

basilar artery infarction

basilar artery stenting

acute ischaemic stroke

Posterior circulation stroke affects the vertebrobasilar artery system and constitutes 20–25% of all ischaemic stroke (IS) cases [1]. It differs from anterior circulation stroke in etiopathogenesis. Studies have shown that the most common stroke aetiology in posterior circulation stroke is IS due to large artery atherosclerosis [2, 3]. The basilar artery (BA) is the major artery of the posterior circulation and provides the main blood supply to this vascular region [4]. The incidence of BA occlusion isn’t known exactly, but it is estimated to account for 1% of all stroke cases [5]. Although atherosclerotic disease of the BA is rare, it is characterised by high mortality and stroke recurrence [6]. Atherosclerotic disease of the BA can have varied presentations and is asymptomatic in some patients. The clinical spectrum in symptomatic patients includes heterogeneous features that can range from minor deficits to coma and death [7, 8]. New endovascular treatment options, which are increasingly available, have expanded the treatment options for these patients. On the basis of the data from the Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis (SAMMPRIS) trial, BA stenting is recommended for patients with recurrent IS with symptomatic BA atherosclerotic stenosis who are undergoing aggressive medical treatment [9, 10]. However, even under aggressive medical treatment, the risk of recurrent IS due to intracranial atherosclerotic stenosis remains high. IS is a heterogeneous group of diseases precipitated by many complicated mechanisms [11]. This study aimed to determine the incidence rate and symptoms of atherosclerotic disease of the BA in an IS population and the factors that affect the clinical outcomes and IS recurrence in symptomatic patients.

In this study, 107 IS patients with atherosclerotic stenosis in the BA who were followed up in our tertiary center between 1 January 2019 and 1 January 2022, were included in the study.

The Clinical Research Ethics Committee of the Bursa Uludag

University, Faculty of Medicine approved the study (26 September 2023;2023-18/24). Need for informed consent was waived by The Clinical Research Ethics Committee of the Bursa Uludag University, Faculty of Medicine. This study was carried out in accordance with the guidelines in the Declaration of Helsinki.

The inclusion criteria for the study were patients diagnosed with IS with clear aetiology and atherosclerotic stenosis in the BA in the emergency who were regularly examined at the neurology outpatient clinic.

The exclusion criteria were failure to clarify the stroke aetiology, BA occlusion, and non-atherosclerotic stenosis (dissection, moyamoya disease) in the BA, being vertebral artery or posterior cerebral artery has more than 50 percent atherosclerotic stenosis.

Between 1 January 2018 and 1 January 2022, 3214 patients were followed up, and 107 patients were included in the study according to the inclusion and exclusion criteria. All patients diagnosed with IS in the emergency department were admitted to the neurology service for further examination and treatment.

All patients underwent brain and neck computed tomographic (CT) angiography, cranial magnetic resonance imaging (MRI), transthoracic echocardiography, and 24-hour rhythm Holter monitoring. In the epicrisis, their medical histories were recorded, including previous diseases, smoking habits, coronary artery disease (CAD), congestive heart failure, hypertension (HT), and diabetes mellitus (DM). The patients' hemogram, biochemistry results, low-density-lipoprotein (mg/dL), (LDL) levels, and HbA1c (%) values were evaluated during their hospitalisation in the neurology ward.

During clinical follow-up, the aim was to keep the LDL level < 100 mg/dL, and medical treatment was started for all the patients.

The patients with HbA1c levels > 7% were evaluated on the basis of endocrinology findings, and HbA1c and LDL values were checked every 3 months. The patients' brain and neck CT angiograms were evaluated by a radiologist (B.H.) with 23 years of neuroradiology experience who was blinded to the clinical findings. The degree of stenosis was determined using the NASCET method.

The posterior cerebral collateral score was determined by evaluating the posterior communicating arteries (PCOMs). All patients were evaluated for the presence and diameter of both PCOMs, according to the following scores: dominant PCOM, 2 points; hypoplastic PCOM, 1 point; and no PCOMs, 0 points. The total scores ranged from 0 to 4. Scores from 0 to 1 were considered bad collateral scores, and scores from 2 to 4 were good collateral scores.

The patients' stroke aetiologies were determined using the TOAST (trial of ORG 10172 in acute stroke treatment) classification [12]. A BA stenosis causing an IS was considered symptomatic. Whether the BA was symptomatic or not was decided by a stroke neurologist. The BA was evaluated in 3 segments: proximal, middle, and distal (Fig. 1).

The stroke mechanisms were evaluated by dividing them into 4 types: artery-to-artery embolism, perforatory stroke, haemodynamic stroke, and IS due to BA occlusion (Fig. 2) [13].

In the 3rd month, the patients' clinical outcomes were determined using the modified Rankin scale (0–2, favourable outcomes and 3–6, unfavourable clinical outcomes).

All the patients underwent regular checkups at the neurology outpatient clinic, where any stroke recurrence was recorded. The patients were followed in accordance with the American Heart Association guidelines. BA stenting was performed in patients with recurrent IS who were undergoing aggressive medical treatment.

Statistical analysis

The patients with atherosclerotic stenosis of the BA were categorised as either symptomatic or non-symptomatic. Receiver-operating characteristic (ROC) analysis was performed to determine the cut-off value of the degree of stenosis. The patients with symptomatic BA stenosis were then categorised according to whether they had stroke recurrence or not and their clinical outcomes.

The clinical properties of the patients in both groups were analysed and compared. A statistical analysis was implemented using the IBM SPSS Statistics 25.0 package (IBM Corp., Armonk, NY). The Shapiro-Wilk test was used to determine the normality of the data distribution. Mean ± SD values were determined for the normally distributed variables, and median (Q1–Q3) values were determined for the non-normally distributed variables. An independent sample T test was performed to analyze the normally distributed variables between the two independent groups, and the Whitney U test was performed for the non-normally distributed variables.

Frequencies and percentages were determined for the categorical variables. The Pearson chi-square test or Fisher exact test was performed to analyse the categorical variables for comparison between the groups. The binary logistic regression model included the variables found to be significant in the univariate analyses. Differences with p values > 0.05 were recognised as statistically significant.

A total of 3285 patients with acute IS were followed up between January 2018 and January 2022 at the Department of Neurology of the Uludag University Faculty of Medicine. A total of 107 patients with atherosclerotic stenosis in the BA who met the inclusion criteria were included in the study. Of these patients, 39 were female, and 68 were male. The mean age was 67.98 ± 9.33 years for all the patients, 67.08 ± 9.51 years for the male patients, and 69.53 ± 8.90 years for the female patients, indicating statistically similar mean ages between the male and female patients (p > 0.05). When the patients' risk factors were evaluated, 88 patients had HT, 64 had diabetes mellitus (DM), 59 were smokers, 31 had congestive heart failure, 45 had CAD, and 15 had atrial fibrillation (AF).

According to stroke aetiology, 77 patients had an IS due to large artery atherosclerosis, 15 had an IS due to cardioembolism, 8 had an IS due to small vessel disease, 1 had an IS due to other causes, and 6 had an IS due to undetermined causes.

When the location of the BA stenosis was examined, atherosclerotic stenosis was detected in the proximal basilar segment in 56 patients, in the mid-basilar segment in 59, and in the distal basilar segment in 7. The BA atherosclerotic stenosis was multisegmented in 13 patients and symptomatic in 69 patients. BA stenting was performed in 29 patients.

As shown in Table 1, the BA atherosclerotic stenosis was symptomatic in 32 of the 56 patients with atherosclerotic stenosis in the proximal segment of the BA. A ROC analysis was performed to evaluate the level of stenosis in the patients with atherosclerotic stenosis in the proximal BA and to differentiate the symptomatic and non-symptomatic patients. The area under the ROC was 0.784 (p < 0.001). The cut-off value was >70%, and the sensitivity and specificity corresponding to this cut-off value were 54.55% and 95.83%, respectively (Figure 3). Of the patients with symptomatic proximal BA atherosclerosis, 24 had an unfavourable clinical outcome, and 8 had a favourable clinical outcome. IS recurrence was observed in 15 patients with symptomatic proximal artery stenosis. When the stroke mechanisms were evaluated, artery-to-artery embolism occurred in 19 patients; penetrating artery infarction, in 18; haemodynamic stroke, in 6; and BA occlusion, in 4. The stroke in 13 patients occurred with a mixed mechanism.

The BA atherosclerotic stenosis was symptomatic in 42 of the 59 patients with atherosclerotic stenosis in the mid-basilar segment. A ROC analysis was performed to evaluate the level of stenosis in the patients with atherosclerotic stenosis in the mid-basilar segment and to differentiate between the symptomatic and non-symptomatic patients. The area under the ROC was 0.718 (p < 0.001). The cut-off value was >70%, and the sensitivity and specificity corresponding to this cut-off value were 52.38% and 88.24%, respectively (Figure 4). Of the patients with symptomatic mid-basilar atherosclerosis, 30 had a favourable clinical outcome, and 12 had an unfavourable clinical outcome. IS recurrence was observed in 15 patients with symptomatic mid-basilary stenosis. When the stroke mechanisms were evaluated, artery-to-artery embolism occurred in 15 patients; IS due to penetrating artery infarction, in 31; IS with a mixed mechanism, in 7; and BA occlusion, in 5. IS occurred with a mixed mechanism in 15 patients.

When the demographic, clinical, and radiological properties of the IS patients with symptomatic BA stenosis and stroke recurrence were examined, the significant variables were artery-to-artery embolism (p = 0.027), BA occlusion (p < 0.001), or a mixed mechanism as the stroke mechanism (p < 0.001); haemoglobin level (p = 0.030); and degree of stenosis (p < 0.001; Table 2).

However, no significant statistical relationship was found between stroke recurrence in the patients with symptomatic BA stenosis and age; sex; the presence of DM, HT, smoking, AF, congestive heart failure, or CAD; clinical outcomes; haemodynamic infarction or perforatory stroke as the stroke mechanism; and stenotic segments of the BA (p > 0.05; Table 2).

Among the variables with a statistically significant relationship with symptomatic BA atherosclerotic stenosis and stroke recurrence that were evaluated using binary logistic regression, the most significant was the degree of stenosis (p < 0.001; odds ratio [OR], 1.074; Table 3).

When the demographic, clinical, and radiological properties of the IS patients with symptomatic BA stenosis and clinical outcomes were examined, the significant variables were sex (p = 0.033), congestive heart failure (p = 0.050); artery-to-artery embolism (p = 0.008), BA occlusion (p < 0.001), or mixed mechanism as the stroke mechanism (p = 0.050); stenosis in the proximal basilary segments (p = 0.007); and stenosis in the mid-basilary segments (p = 0.020; Table 4).

However, no significant statistical relationships were found between the clinical outcomes of the patients with symptomatic BA stenosis and age; the presence of HT, DM, smoking, AF, or congestive heart failure; perforatory stroke, haemodynamic stroke, or BA occlusion as the stroke mechanism; stenosis in the distal basilar segment; multi-segment stenosis; stroke recurrence; degree of stenosis; and BA stenting procedure (p > 0.05; Table 4).

Among the variables with a statistically significant relationship with symptomatic BA atherosclerotic stenosis and unfavourable clinical outcomes that were evaluated using binary logistic regression, the most significant were sex (p = 0.06; OR, 9.776), congestive heart failure (p = 0.013; OR, 10.133), artery-to-artery embolism as the stroke mechanism (p = 0.042; OR, 3.874), atherosclerotic stenosis in the proximal BA (p = 0.022; OR, 4.716; Table 5).

According to the results of this study, the degree of atherosclerotic stenosis in symptomatic BA was an independent risk factor of stroke recurrence. The independent risk factors of unfavourable clinical outcomes in these patients were female sex, stenosis in the proximal segment, artery-to-artery embolism as the stroke mechanism, and congestive heart failure. The incidence of intracranial atherosclerotic disease is increasing with the ageing of society. A recent study reported that intracranial atherosclerotic stenosis most frequently occurs in the BA in IS patients [14]. In patients with IS due to intracranial atherosclerotic disease, stenting is recommended in the presence of recurrent IS under aggressive medical treatment. This recommendation is based on data from the SAMMPRIS trial [9, 10]. However, even under aggressive medical treatment, the risk of recurrent IS due to intracranial atherosclerotic stenosis remains high.

In our study, atherosclerotic stenosis of the BA was detected in 107 patients, of whom 69 (64.48%) were symptomatic. The mean follow-up period of the asymptomatic patients was 28.00 ± 18.034 months. None of the patients in the asymptomatic group had IS under aggressive medical treatment. The mean follow-up period in the symptomatic group was 25.53 ± 17.842 months. Of the 69 symptomatic patients, 30 (43.47%) had recurrent IS during the follow-up period. As this incidence rate was based on real-life data, it is much higher than those reported in randomised studies [10].

In our study, stenosis was detected in the proximal BA in 32 patients, in the mid-basilar segment in 42, and in the distal BA in 6. The stenosis was multisegmented in 13 patients. According to the findings of this study, atherosclerotic stenosis was most frequent in the mid-basilar segment but was rare in the distal BA. Similar incidence rates were obtained from the data reported by Edgar et al. [6].

The degree of stenosis was established to be an independent risk factor of stroke recurrence in patients with symptomatic BA stenosis. According to the data from the Comparison of Warfarin and Aspirin for Symptomatic Intracranial Arterial Stenosis (WASID) trial, the degree of stenosis is related to stroke recurrence [15]. In our study, the independent risk factor of unfavourable clinical outcomes was female sex. The relationships between sex and IS and atherosclerosis are complex. Atherosclerosis has a different course in women and men. Atherosclerotic lesions progress slowly starting from the fourth and fifth decades in men and progress rapidly in women, starting from the sixth decade [16–18]. Studies have indicated that stroke has a worse clinical outcome in women [19]. To our knowledge, no studies have reported the relationship between sex and IS due to BA atherosclerosis. Data from randomised studies that evaluated symptomatic intracranial atherosclerotic stenosis have indicated that while no sex-related difference was found in the Chinese Intracranial Atherosclerosis (CICAS) trial, female sex was found to be a poor prognostic factor in the WASID trial [15, 20].

The most common stroke mechanism in patients with symptomatic BA atherosclerosis is perforatory stroke. MRI studies have shown that BA plaques have a long distribution and affect the ventral, dorsal, and lateral walls equally. These plaques do not have the same characteristics as those in the coronary and middle cerebral arteries. In addition, plaques in the BA tend to settle adjacent to the orifices of the penetrating arteries [21]. This can explain why the most common stroke mechanism is perforatory stroke.

Arterial-to-artery stroke mechanism is an independent risk factor of unfavourable clinical outcomes. A recent study found a correlation between the morphological features of plaques and IS mechanism due to symptomatic posterior intracranial atherosclerosis. The authors found that unstable plaques with a higher plaque burden and irregular surfaces were symptomatic of artery-to-artery embolism [22]. In intracranial atherosclerotic disease, IS due to an artery-to-artery embolic stroke mechanism is a poor prognostic factor [6, 13].

Unfavourable clinical outcome is another independent risk factor. Congestive heart failure is quite common in the stroke population. It is also an important risk factor of IS in the normal population [23–26]. Morbidity and mortality rates were found to be higher in IS patients with congestive heart failure [27]. This relationship may be the result of the close relationship between heart failure and atherosclerotic vascular disease.

Limitations of the study

The major limitation of this study is due to its retrospective nature and data from a single centre. More accurate information can be obtained through multi-centre prospective studies.

The most remarkable result of our study is that clinical outcomes were closely related to the female sex, artery-to-artery embolism as the stroke mechanism, and stenosis in the proximal segment. In patients with symptomatic BA stenosis, studies are needed to examine the effects of IS mechanisms and plaque morphologies on long-term stroke recurrence and clinical outcomes. Stroke mechanisms must be evaluated more clearly so that individualised treatments can be provided to these patients.

Author Contribution

Author Contribution:Concepts: YDDesign: YDDefinition Of İntellectual Content:MB, YDLiterature Search:YD, GM, FH, EOA, FSClinical Studies: YD, GM, FH, EOA, FSExperimental Studies:-Data Acquisition:YD, GM, FH, EOA, FSData Analysis: DS, YD, RO, GM, FH, SGStatistical Analysis: DS, YDManuscript Preparation:YD, EOA, FSManuscript Editing: MB, BHManuscript Review: MB, BHGuarantor: YDCorresponding Author: YD

Data availability:

All authors accept to share data if it is necessary

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Table 1: Clinical properties of proxymal and mid-basilar artery stenosis

Properties	Symptomatic proximal basilar artery stenosis n=56	Symptomatic mid-basilar stenosis n=59
Symptomatic basilar artery stenosis	32(57.14%)	42(71.18%)
Stroke recurrence due to basilary artery stenosis	15(26.78%)	15(25.42%)
Stroke mechanism
artery-to-artery embolism due to basilary artery stenosis	19(33.92%)	15(25.42%)
Perforators stroke due to basilary artery stenosis	18(32.14%)	31(52.54%)
Hemodynamic stoke due to basilary artery stenosis	6(10.71%)	7(11.86%)
Stroke due to basilar artery occlusion	4(7.14%)	5(8.47%)
Mix mechanism	13(23.21%)	15(25.42%)
Favorable clinical outcome	8(14.28%)	30(50.84%)
Unfavorable clinical outcome	24(42.85%)	12(20.33%)
Follow-up perıod of patıents (Month)	23.50 ±17.63	29.93 ±17.78

Table 2. Evaluation of variables affecting stroke recurrence in acute ischemic stroke patients with atherosclerotic stenosis in the symptomatic basilar artery

Variables	Ischemic Stroke Due to Symptomatic Basilar Artery Atherosclerotic stenosis with Stroke Recurrence (n=30)	Ischemic Stroke Due to Symptomatic Basilar Artery Atherosclerotic stenosis without Stroke Recurrence (n=39)	p-value
Age*	66.50±7.97	67.64±10.15		0.614
Sex** (male gender)	19(63.33%)	19(48.71%)		0.226
Diabetes**	19(63.33%)	26(66.66%)		0.773
Hypertension**	26(86.66%)	31(79.48%)		0.435
Smoker**	16(53.33%)	20(51.28%)		0.886
Atrial fibrilation**	16(53.33%)	20(51.28%)		0.646
Congestive heart failure**	4(13.33%)	10(25.64%)		0.208
Coroner artery disease**	10(33.33%)	15(38.46%)		0.660
Hemoglobin(g/dL)*	13.25(11.85,14.00)	13.80(12.58,14.70)		0.030
LDL(mg/dL)*	151.50(100.00,185.00)	138.50(112.25,174.75)		0.607
Stroke mechanism
Artery-to-artery embolism **	18(60%)	10(25.64%)		0.027
Perforators infarction**	16(48.48%)	28(71.79%)		0.114
Hemodynamic infarction	7(23.23%)	5(12.82%)		0.253
Basilar artery occlusion	9(30%)	0(0%)		<0.001
Mix mechanism	18(60%)	8(20.51%)		<0.001
Stenotic segment of the basilar artery
Proximal segment**	15(50%)	17(43.58%)		0.506
Middle segment**	15(50%)	27(69.23%)		0.105
Distal segment**	3(10%)	3(7.69%)		1.000
Multisegment stenosis**	3(10%)	6(15.28%)		0.722
Stenosis degree(%)	66,28±20.70	85.50±10.77		<0.001
Clinical outcome** Unfavorable clinical outcome	11(%36.66)	11(%28.20)		0.455
Posterior collateral scores (poor collateral scores)	13(43.33)	14(35.89)		0.530

Significant variables are shown in bold. *Mann-Witney U test, **Pearson chi-square test/continuity correction test/Fisher Exact test.Abbreviations: LDL, Low-Density Lipoprotein.

Table 3. Significant variables of stroke recurrence in acute ischaemic stroke patients with atherosclerotic stenosis in the symptomatic basilar artery

	p-value	Odds ratio	lower	upper
	p-value	Odds ratio	%95 C.I
Stroke mechanism being artery to artery embolism Ref: Absent vs present	0.151	2.315	0.736	7.283
Stenosis degree	<0.001	1.074	1.029	1.119
Heamoglobin(g/dL)	0.393	0.986	0.899	1.043

Significance of the model p<.001. Significant variables are shown in bold. Ref = references, vs = versus.

Table 4: Table 2. Evaluation of variables affecting clinical outcomes in acute ischemic stroke patients with atherosclerotic stenosis in the symptomatic basilar artery

Variables	Patients with acute stroke due to basilar artery stenosis with unfavorable clinical outcome n=22	Patients with acute stroke due to basilar artery stenosis with favorable clinical outcome n=47	p-value
Age	70.00±7.91	65.80±9.55		0.078
Sex (male gender)	8(%36.36)	30(%52.63)		0.033
Hypertension	18(%81.81)	39(%68.42)		1.000
Diyabetes mellitus	16(%72.72)	29(%61.70)		0.370
Smoker	9(%40.90)	27(%57.44)		0.200
Atrial fibrilation	1(%4.54)	4(%8.51)		1.000
Congestive heart failure	8(%36.36)	6(%17.76)		0.050
Coroner artery disease	9(%40.90)	16(%34.04)		0.580
Stroke mechanism
Artery-to-artery embolism	15(%68.18)	16(%34.04)		0.008
Perforators stroke	11(%50.00)	33(%70.21)		0.104
Hemodynamic stroke	4(%18.18)	8(%17.02)		1.000
Basilar artery occlusion	5(%22.72)	4(%8.51)		0.132
Mix mechanism	12(%54.54)	14(%29.78)		0.050
Segment of basilary artery
Proximal segment	15(%68.18)	17(%36.17)		0.007
Mid-basilar segment	9(%40.90)	33(%70.21)		0.020
Distal segment	3(%13.63)	3(%6.38)		0.375
Multi-segment stenosis	4(%18.18)	5(%10.63)		0.452
Stroke recurrence	11(%50.00)	19(%40.42)		0.455
Degree of stenosis	74.00(57.50,95,00)	80.00(60.00,90.00)		0.891
Basilar artery stenting	6(%27.27)	21(%44.68)		0.167
Posterior collateral scores (poor collateral scores)	8(%36.66)	19(%40.42)		0.747

Significant variables are shown in bold. *Mann-Witney U test, **Pearson chi-square test/continuity correction test/Fisher Exact test.

Table 5. Significant variables of clinical outcome in acute ischaemic stroke patients with atherosclerotic stenosis in the symptomatic basilar artery

	p-value	Odds ratio	lower	Upper
	p-value	Odds ratio	%95 C.I
Sex Ref: female gender	0.006	9.776	1.049	14.285
Congestive heart failure Ref: present vs absent	0.013	10.133	1.625	63.181
Stroke mechanism being artery-to-artery embolism Ref: present vs absent	0.042	3.874	1.049	14.285
Atherosclerotic stenosis in the proximal basilar artery Ref: present vs absent	0.022	4.716	1.245	17.868

Significance of the model < 0.001. Significant variables are shown in bold. Ref = references, vs = versus.

No competing interests reported.

Characteristics That Affect the Long-term Clinical Outcome and Stroke Recurrence in Ischaemic Stroke Patients With Basilar Artery Atherosclerosis

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Abstract

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INTRODUCTION

MATERIALS AND METHODS

Statistical analysis

RESULTS

DISCUSSION

Limitations of the study

Conclusion

Declarations

Author Contribution

Data availability:

References

Tables

Additional Declarations

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