Impact of atrial fibrillation in clinical outcomes of low gradient aortic stenosis

Introduction

Aortic stenosis (AS) is the most common significant valvular heart disease in developed countries. A significant portion of the AS populations have low-gradient AS (LGAS), defined as aortic valve area ≤1.0 cm2 and a trans-aortic mean systolic gradient and peak velocity <40 mmHg and <4 m/s, respectively. LGAS has been shown previously to have worse mortality compared to high-gradient AS (HGAS). Atrial fibrillation (AF) is associated with LGAS and AF has been associated with worse outcomes compared to sinus rhythm (SR) in HGAS. The prognostic impact of AF in LGAS is not well described in previous literature.

Hypothesis

AF will be associated with worse clinical outcomes compared to SR in patients with LGAS.

Methods

3400 patients diagnosed with LGAS from 2010–2020 were retrospectively identified and analyzed. Their electrical rhythm was analyzed at the time of their echocardiographic diagnosis of LGAS and patients were split into 3 separate groups: SR (n=2036), SR with history of AF (n=519), and AF (n=845). After adjustment for age, sex, and Charlson Comorbidity Index (CCI), primary endpoints of overall mortality and cardiac mortality were assessed for patients.

Results

Compared to those with SR, patients with AF and history of AF had significantly higher overall mortality (HR 1.52, p<0.0001 and HR 1.22, p=0.004, respectively) and cardiac mortality (HR 2.05, p<0.0001 and HR 1.37, p=0.03, respectfully) (Figure 1). On further sub group analysis, AF seemed to be most importantly associated with mortality and cardiac mortality in patients with preserved ejection fraction (EF >50%, normal flow LGAS) compared to those patients with reduced EF (classical low-flow LGAS), where there was no statistically significant difference in outcomes between AF and SR (Figure 2).

Conclusions

Atrial fibrillation, compared to sinus rhythm, is associated with worse overall mortality and cardiac mortality in patients with LGAS and preserved EF. Specifically, this association was strongest in patients with preserved EF >50%. Given these findings, the presence of AF should be factored into clinical decision making regarding LGAS management given the higher risk of age, sex, and CCI adjusted overall and cardiac mortality. Further research needs to be done to see if earlier aortic valve intervention in these patients would improve mortality compared to their SR counterparts.

Funding Acknowledgement

Type of funding sources: None.

Glucocorticoid therapy rather than the inflammatory state is associated with pulmonary embolism and deep vein thrombosis in cardiac sarcoid

Background

Sarcoidosis is an infiltrative inflammatory condition affecting multiple organs, with cardiac involvement designated as cardiac sarcoidosis (CS). It has been proposed that inflammatory conditions like sarcoid increase the risk of venous thromboembolism (VTE), defined as pulmonary embolism (PE) and deep vein thrombosis (DVT) due to the hypercoagulable environment created by inflammation.

Purpose

Although previous studies have demonstrated an association with sarcoidosis and VTE, these studies failed to account for steroid use (crucial for sarcoid treatment) as an important confounder. Also, no major studies have been done previously assessing the risk of VTE in CS specifically. The objective of this investigation is to determine the association between CS, steroid treatment for CS, and VTE.

Methods

Patients referred to our institution with concern for sarcoid/CS were retrospectively assessed. Specific variables of interest including general baseline characteristics and those specific to CS were analyzed for their association with VTE development.

Results

Using Heart Rhythm Society guidelines, 649 patients were split into three categories: 235 with no sarcoid (NS), 91 with extra-cardiac sarcoid (ECS) only, and 323 with CS. In univariate analysis, 39 (12%) CS patients developed a PE vs 9 (4%) NS patients (OR 3.44, p=0.0003) and 44 (14%) CS patients developed DVT vs 18 (8%) NS patients (OR 1.90, p=0.02). In multivariate regression analysis however, neither CS nor ECS was an independent risk factor for VTE (p>0.05) but steroid use was a strong predictor of VTE (HR 3.12, p=0.007 for PE, HR 6.17, p<0.0001 for DVT). Also, steroid dose was found to be an independent predictor for both PE (p=0.001) and DVT (p=0.007) in a Cox proportionate hazards model (significance appeared at >17.5 mg daily on a receiver operating characteristic curve).

Conclusion

Contrary to previous studies, the current study found that neither sarcoidosis nor CS is an independent risk factor for VTE. Rather, steroid therapy for CS treatment leads to an increased prevalence of VTE, specifically at a dose above 17.5 mg daily. More research is required to clarify this relationship and assess the importance of steroid-sparing immunosuppressive therapy and potentially VTE prophylaxis in CS management.

Steroid use and time to PE/DVT

Funding Acknowledgement

Type of funding source: None

P1805Troponin-T, NT-proBNP and creatinine at presentation predict outcomes in patients with cardiac sarcoidosis

Background

Cardiac sarcoidosis (CS) is an infiltrative inflammatory condition defined by infiltration of noncaseating granulomas into the heart. Based on the location of sarcoid lesion involvement, patients can present with symptoms of congestive heart failure, arrhythmias, and even sudden cardiac death.

Purpose

Diagnosis of CS has been somewhat challenging, with the Heart Rhythm Society (HRS) and Japanese Ministry of Health and Welfare (JMHW) being the 2 widely accepted diagnostic guidelines. Endomyocardial biopsy is the gold standard to prove definite CS but has a low sensitivity. Imaging studies have been helpful as non-invasive methods to diagnose probable CS but these can be logistically difficult and expensive. Thus, investigating for laboratory biomarkers that can act as both diagnostic and prognostic can be crucial in how we diagnose and manage CS in the future.

Methods

Patients meeting HRS for CS were evaluated at a single institution (n=217). Biomarkers of interest included angiotensin-converting enzyme (ACE), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), N-terminal pro B-type natriuretic peptide (NT-proBNP), troponin-T, 1,25 dihydroxyvitamin D (1,25-OHVit-D), and creatinine. Biomarkers were stratified by clinical variables of interest and their association with prognosis was examined. The primary endpoint was LVAD implantation, transplantation, or death.

Results

Mean values on presentation were: ACE 32.9±28, ESR 12±13, CRP 7.4±19, NT-proBNP 1630±2923, Troponin-T 0.03±0.1, 1,25-OHVit-D 55.5±20, and creatinine 1.12±0.3. None of the biomarkers differed by sex, definite or probable CS, or a history of immunosuppression. ACE levels were associated with the presence of cardiac fibrosis on cardiac MRI (mean difference 14.7, p=0.032). Troponin-T (p=0.006; HR 1.06 per 0.01 ng/mL), NT-proBNP (p=0.0003; HR 1.31 per 1,000 pg/mL), and creatinine (p=0.01; HR 4.02 per mg/dL) were each associated with the primary endpoint (52/217 patients).

Biomarkers associated with long term outcomes in patients with cardiac sarcoidosis Biomarker Hazard ratio P value Troponin-T 1.06 (1.02–1.11)* 0.006 NT-pro BNP 1.31 (1.15–1.48)** 0.0003 Creatinine 4.02 (1.41–9.94)*** 0.01 *Per 0.01 ng/mL change; 99th percentile upper reference limit <0.01 ng/mL; **per 1,000 pg/mL change; ***per 1 mg/dL change.

Conclusion

Troponin-T, NT-proBNP, and creatinine at presentation predict outcomes in patients with CS. Further investigation on the utility of biomarkers for assessment of disease activity and treatment response is warranted.

5879Coronary microvascular dysfunction is associated with poor glycemic control in women with diabetes presenting with chest pain and non-obstructive coronary artery disease

Background

Patients with type 2 diabetes are at an increased risk of cardiovascular events compared to individuals without diabetes. The role glycemic control plays in reducing cardiovascular risk remains uncertain. Coronary microvascular dysfunction (CMD) is more frequent in women compared to men, is prevalent in patients with type 2 diabetes and is linked to adverse cardiovascular events. We compared the association between CMD and glycemic control across sexes in patients with chest pain and non-obstructive coronary artery disease (CAD).

Methods

Patients with chest pain who were found to have non-obstructive CAD (stenosis <40%) at angiography underwent an invasive assessment of endothelial-independent and endothelial–dependent coronary microvascular function. Using a Doppler guidewire, endothelial-independent microvascular function was assessed by measuring the coronary flow velocity in response to intracoronary adenosine and comparing this to baseline to calculate the coronary flow reserve ratio (CFRAdn). A CFRAdn ≤2.5 was considered abnormal. Endothelial-dependent microvascular function was assessed by measuring the percent change in coronary blood flow in response to intracoronary infusions of acetylcholine (%ΔCBFAch), with a %ΔCBFAch ≤50% considered abnormal. Patients were classified as having normal versus abnormal CFRAdn and %ΔCBFAch. Measurements of HbA1c and fasting serum glucose were obtained at the time of catheterization and compared between groups after stratification by sex.

Results

Between 1993 and 2012, 1,469 patients (mean age 50.4 years, 35% male) underwent coronary angiography and invasive testing for CMD, of which 129 (8.8%) had type 2 diabetes. Fifty one (39.5%) had an abnormal %ΔCBFAch and 49 (38.0%) had an abnormal CFRAdn. Conventional cardiovascular risk factors did not vary significantly between groups. Females with an abnormal CFRAdn or abnormal %ΔCBFAch had a significantly higher HbA1c compared to those with a normal CFRAdn or %ΔCBFAch respectively: HbA1c % (standard deviation) 7.4 (2.1) vs. 6.5 (1.1), p=0.035 and 7.3 (1.9) vs. 6.4 (1.2), p=0.022, respectively. Females with an abnormal CFRAdn had significantly higher fasting serum glucose concentrations compared to those with a normal CFRAdn: fasting serum glucose mg/dL (standard deviation) 144.4 (55.6) vs. 121.9 (28.1), p=0.035. These effects were not observed in men. Amongst female diabetics, a higher HbA1c was significantly associated with any CMD after adjusting for covariates: odds ratio (95% confidence interval) 1.69 (1.01 – 2.86) p=0.049; and a fasting serum glucose >140 mg/dL was significantly associated with an abnormal CFRAdn, 4.28 (1.43–12.81).

Conclusion

Poor glycemic control is associated with CMD in females with diabete who present with chest pain and non-obstructive CAD. These findings highlight the importance of sex-specific risk stratification models and treatment strategies when managing cardiovascular risk in diabetics.

Acknowledgement/Funding

Mayo Foundation

Towards lab-on-a-chip diagnostics for malaria elimination

Malaria continues to be one of the most devastating diseases impacting global health. Although there have been significant reductions in global malaria incidence and mortality rates over the past 17 years, the disease remains endemic throughout the world, especially in low- and middle-income countries. The World Health Organization has put forth ambitious milestones moving toward a world free of malaria as part of the United Nations Millennium Goals. Mass screening and treatment of symptomatic and asymptomatic malaria infections in endemic regions is integral to these goals and requires diagnostics that are both sensitive and affordable. Lab-on-a-chip technologies provide a path toward sensitive, portable, and affordable diagnostic platforms. Here, we review and compare currently-available and emerging lab-on-a-chip diagnostic approaches in three categories: (1) protein-based tests, (2) nucleic acid tests, and (3) cell-based detection. For each category, we highlight the opportunities and challenges in diagnostics development for malaria elimination, and comment on their applicability to different phases of elimination strategies.