Characteristics and outcomes of aortic stenosis patients with and without stroke

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Sia CH was supported by the National University of Singapore Yong Loo Lin School of Medicine’s Junior Academic Faculty Scheme

Background

Aortic stenosis (AS) is related to several atherosclerosis risk factors and is associated with an increased risk of ischaemic stroke. Some reports suggest that aortic valve calcification may predispose to embolic stroke although this is not well-studied. The literature is also sparse regarding individual stroke subtypes and predictors of stroke in AS.

Purpose

We aimed to 1) Describe rates of ischaemic stroke in AS including specific stroke subtypes; 2) Compare clinical and echocardiographic characteristics of patients with AS who subsequently developed ischaemic stroke versus those who did not, and 3) Identify independent variables associated with subsequent stroke in AS.

Methods

Patients with AS were recruited from an echocardiography database from September 2011 to December 2015 at a single tertiary centre. The primary study endpoint was acute ischaemic stroke. Clinical characteristics and echocardiographic parameters were compared between patients who suffered a stroke after AS diagnosis and those who did not. Multivariable Cox regression analysis was used to identify factors associated with subsequent stroke.

Results

A total of 703 patients with AS were studied, with a median follow-up duration of 3.0 (IQR 0.5, 5.0) years. Twenty-two patients (3.1%) developed stroke following AS diagnosis (large vessel, 18.2%; cardioembolic, 50.0%; small vessel, 18.2%; other determined ischaemic stroke, 13.6%). These patients had a greater prevalence of previous stroke or transient ischaemic attack (TIA) (50.0%) compared to patients who did not develop subsequent stroke (20.9%), p<0.001. Patients with AS who developed subsequent stroke also more commonly had atrial fibrillation at the time of indexed echocardiography (40.0%) compared to their counterparts who did not develop stroke (13.5%), p=0.004 (Table 1). Other cardiovascular risk factors and traditional echocardiographic parameters of AS severity were similar between the 2 groups. Degenerative calcified aortic valve was not associated with the development of all types of ischaemic stroke or cardioembolic stroke. AS severity was also not associated with development of stroke. Multivariable Cox regression analysis found previous stroke or TIA (HR 8.00, 95% CI 2.70–23.58, p<0.001) and atrial fibrillation at time of echocardiography (HR 8.81, 95% CI 1.34–10.80, p=0.012) to be independent predictors of subsequent stroke in AS. The key findings of our study are summarised in Figure 1.

Conclusions

Cardioembolic stroke is the most common stroke subtype in patients with AS. Previous history of stroke or TIA and atrial fibrillation at time of diagnostic echocardiography are independent predictors of subsequent stroke in AS. Calcified aortic valve was not found to be a risk factor for all types of ischaemic stroke or cardioembolic stroke.

Stress hyperglycaemia is associated with poor functional outcomes in patients with acute ischaemic stroke after intravenous thrombolysis

BACKGROUND

Transient hyperglycaemia in the context of illness with or without known diabetes has been termed as 'stress hyperglycaemia'. Stress hyperglycaemia can result in poor functional outcomes in patients with acute ischaemic stroke (AIS) who underwent mechanical thrombectomy. We investigated the association between stress hyperglycaemia and clinical outcomes in AIS patients undergoing intravenous thrombolysis (IVT).

METHODS

We examined 666 consecutive patients with AIS who underwent IVT from 2006 to 2018. All patients had a glycated haemoglobin level (HbA1c) and fasting venous blood glucose measured within 24 h of admission. Stress hyperglycaemia ratio (SHR) was defined as the ratio of the fasting glucose to the HbA1c. Univariate and multivariate analyses were employed to identify predictors of poor functional outcomes (modified Rankin Scale 3-6 at 3 months) after IVT.

RESULTS

Three-hundred and sixty-one patients (54.2%) had good functional outcomes. These patients tended to be younger (60.7 ± 12.7 vs. 70 ± 14.4 years, P < 0.001), male (70.7% vs. 51.5%, P < 0.001), had lower prevalence of atrial fibrillation (13.0% vs. 20.7%, P = 0.008) and lower SHR (0.88 ± 0.20 vs. 0.99 ± 26, P < 0.001). Patients with high SHR (≥0.97) were slightly older than those with low SHR (<0.97) and were more likely to have diabetes mellitus. On multivariate analysis, higher SHR was independently associated with poor functional outcomes (adjusted odds ratio 3.85, 95% confidence interval 1.59-9.09, P = 0.003).

CONCLUSION

SHR appears to be an important predictor of functional outcomes in patients with AIS undergoing IVT. This may have important implications on the role of glycaemic control in the acute management of ischaemic stroke.

Fever as a predictor of adverse outcomes in COVID-19

BACKGROUND/INTRODUCTION

There are little data on outcomes of COVID-19 patients with the presence of fever compared to the presence of symptoms.

AIM

We examined the associations between symptomology, presence of fever and outcomes of a COVID-19 cohort.

DESIGN AND METHODS

Between 23 January and 30 April 2020, 554 COVID-19 patients were admitted to a tertiary hospital in Singapore. They were allocated into four groups based on symptomology and fever-Group 1: asymptomatic and afebrile, Group 2: symptomatic but afebrile, Group 3: febrile but asymptomatic and Group 4: symptomatic and febrile. The primary outcomes were intensive care unit (ICU) admissions and mortality. The composite end-point included ICU admissions, mortality or any COVID-19 related end-organ involvement.

RESULTS

There were differences in ferritin (P=0.003), C-reactive protein (CRP) levels (P<0.001) and lymphopenia (P=0.033) across all groups, with the most favourable biochemical profile in Group 1, and the least in Group 4. Symptomatic groups (Groups 2 and 4) had higher ICU admissions (1.9% and 6.0%, respectively, P=0.003) than asymptomatic groups (Groups 1 and 3). Composite end-point was highest in Group 4 (24.0%), followed by Group 3 (8.6%), Group 2 (4.8%) and Group 1 (2.4%) (P<0.001). The presence of fever (OR 4.096, 95% CI 1.737-9.656, P=0.001) was associated with the composite end-point after adjusting for age, pulse rate, comorbidities, lymphocyte, ferritin and CRP. Presence of symptoms was not associated with the composite end-point.

DISCUSSION/CONCLUSION

In this COVID-19 cohort, presence of fever was a predictor of adverse outcomes. This has implications on the management of febrile but asymptomatic COVID-19 patients.

Low Relative Valve Load is Associated With Paradoxical Low-Flow Aortic Stenosis Despite Preserved Left Ventricular Ejection Fraction and Adverse Clinical Outcomes

BACKGROUND

Paradoxical low-flow (LF) severe aortic stenosis (AS) despite preserved left ventricular (LV) ejection fraction (LVEF) has been shown to be distinct from normal-flow (NF) AS, with a poorer prognosis. Relative valve load (RVL) is a novel echocardiographic haemodynamic index based on the ratio of transaortic mean pressure gradient to the global valvulo-arterial impedance (Zva) in order to estimate the contribution of the valvular afterload to the global LV load. We aimed to determine the usefulness of RVL in LF AS versus NF AS.

METHOD

A total of 450 consecutive patients with medically managed severe AS (aortic valve area <1.0 cm²) with preserved LVEF (>50%) were studied. Patients were divided into LF (stroke volume index <35 mL/m²) or NF, and high RVL or low RVL. Baseline clinical and echocardiographic profiles, as well as clinical outcomes, were compared.

RESULTS

There were 149 (33.1%) patients with LF. Despite higher global impedance in LF (Zva 6.3±2.4 vs 3.9±0.9 mmHg/mL/m²; p<0.001) compared with NF, the RVL in LF AS was significantly lower (5.4±2.7 vs 9.8±5.1 mL/m²; p<0.001). On multivariable analysis, low RVL (≤7.51) remained independently associated with poor clinical outcomes on Cox regression (hazard ratio, 1.31; 95% confidence interval, 1.03-1.68), with 53.2% sensitivity and 70.3% specificity. This was comparable to other prognostic indices in AS. Kaplan-Meier curves demonstrated that low RVL was associated with increased mortality.

CONCLUSIONS

Increased systemic arterial afterload may be important in the pathophysiology of LF AS. Low RVL was an independent predictor of poor clinical outcomes in medically managed severe AS. There may be a greater role in the attenuation of systemic arterial afterload in AS to improve outcomes.