Clinical value of stress transaortic flow rate during dobutamine echocardiography in low-gradient aortic stenosis

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND/INTRODUCTION

The clinical value of rest transaortic flow rate (FR) has been shown previously in low-gradient aortic stenosis (LGAS) for the prediction of outcome. However limited data exists on the prognostic value of stress FR in LGAS following low-dose dobutamine stress echocardiography (LDDSE).

PURPOSE

We aimed to assess the value of stress FR in patients with LGAS in the diagnosis of AS severity and the prediction of mortality.

METHODS

This is a multi-centre cohort study of patients with low left ventricular ejection fraction (LVEF) and LGAS (aortic valve area –AVA <1cm²) who underwent LDDSE.

RESULTS

Of the 287 patients (mean age:  75.1 ±10 years, males: 71%) over the mean follow-up of 24 ±30 months there were 127 (44.3%) deaths and 147 (51.2%) patients underwent aortic valve intervention. Lower stress FR was independently associated with increased risk of mortality (HR= 0.99, 95%CI= 0.99-0.999, p= 0.02) after adjusting for age, chronic kidney disease, presence of symptoms (NYHA II-IV), aortic valve intervention, rest LVEF and guideline-defined severe AS (AV mean gradient- AVMG ≥40mmHg with AVA <1cm² at peak stress).  The minimum cut-off for prediction of mortality was stress FR 210ml/sec. Among the different criteria of AS severity during stress, i.e. guideline-defined criterion, or stress AVMG ≥40mmHg, or stress AVA <1cm² at stress FR ≥210ml/s, only the latter was independently associated with mortality (HR= 1.81, 95%CI= 1.04-3.2, p= 0.04) (Table 1) and was the parameter of AS severity that predicted improved outcome following aortic valve intervention (p <0.005) (Figure 1). Guideline-defined stroke volume flow reserve did not predict mortality.

CONCLUSIONS

Assessment of stress FR during LDDSE is important for the detection of both AS severity and flow reserve.

Table 1 Multivariable analysis for prediction of all-cause mortality (N = 287) for the different criteria of aortic stenosis HR 95%CI p Age 1 0.98-1.03 0.84 Chronic kidney disease 1..84 1.13-2.99 0.01 Aortic valve intervention 0.37 0.22-0.61 <0.005 Presence of symptoms (NYHA II-IV) 1.87 0.66-5.31 0.24 Rest LVEF (by 1%) increase 0.97 0.95-1 0.06 Stress AVA < 1cm² with stress AVMG≥40mmHg 1.02 0.31-3.34 0.97 Stress AVMG≥40mmHg 0.57 0.2-1.59 0.28 Stress AVA < 1cm² at stress FR≥210mmHg 1.81 1.04-3.2 0.04 Abstract Figure 1

Coronary computed tomography versus stress echocardiography-guided management of stable chest pain patients: a propensity matched analysis

Background

Recent recommendations by national and international societies advocate the use of coronary computed tomography (CCT) as the first-line test for the assessment of low-risk patients with suspected stable angina. However limited real-life data exist regarding its relative clinical value versus stress echocardiography (SE)-guided management.

Purpose

We aimed to assess in a real-life setting the clinical value of stress echocardiography (SE)-guided versus CCT-guided management in patients presenting with stable chest pain and no prior history of coronary artery disease (CAD).

Methods

We compared the relative feasibility, efficacy and the proportion of patients undergoing downstream testing including revascularisation and their impact on outcome (mortality and myocardial infarction) when CCT versus SE were used as the first line test for the assessment of stable chest pain.

Of the patients who underwent CCT (N=2192) or SE (N=2081) between October 2013 and October 2014 only those with suspected stable angina and without previous CAD were selected. The population was propensity-matched (total 1980 patients-990 patients each group) to account for differences in the baseline cardiovascular risk factors.

Results

The mean age of the population was 59±13.2 years and 949 (47.9%) patients were male. Inconclusive tests were 6% versus 3% (p<0.005) in CCT versus SE. Severe (>70%) luminal stenosis on CCT and inducible ischemia on SE detected obstructive CAD by invasive coronary angiography in 63% versus 57% patients (p=0.33). Over the entire follow-up period (median 717 (IQR 93–1069) days) significantly more patients underwent invasive coronary angiography (21.5% versus 7.3%, p<0.005) and revascularisation (33.5% versus 3.5%, p<0.005) respectively in the CCT versus the SE group. Following their initial assessment 336 (33.9%) patients in the CCT and 86 (8.7%) in the SE group underwent further functional testing (SE, stress cardiac MRI, exercise electrocardiography) (p<0.005) (Figure 1A). There was no difference in all-cause mortality (p=0.26) or death and myocardial infarction (p=0.16) between the two groups (Figure 1B).

Conclusions

SE when used for the assessment of patients with stable angina and no prior CAD resulted in more conclusive tests, similar detection of obstructive CAD, less overall invasive coronary angiography and revascularization and less subsequent functional tests compared with CCT.

Figure 1

Funding Acknowledgement

Type of funding source: None

Demographic characteristics, aortic valve intervention rates and all-cause mortality in 4 flow-gradient sub-types of severe aortic stenosis

Introduction

Severe aortic stenosis (AS), defined as aortic valve area (AVA) <1.0 cm2, can be divided into 4 categories based on flow status and mean gradient. Stroke volume index <35 ml/m2 has classically been used to define low flow, but recent data suggest that flow rate (FR) <200ml/sec may be a more accurate and robust marker of low flow.

Methods

We prospectively collected demographic, echocardiographic, aortic valve intervention (AVI) and all-cause mortality data on 1562 patients with symptomatic severe AS from 2010 to 2017 with a mean follow up period of 35±22 months. Patients were divided into 4 flow-gradient sub-groups based on a FR threshold of 200ml/s and mean pressure gradient of 40mmHg. Comparative analyses were performed among the 4 groups using analysis of variance.

Results

The prevalence of normal flow high gradient (NFHG) severe AS was 30%, NF low gradient (NFLG) 21%, low flow HG (LFHG) 18% and LFLG 31% (Table). Across these 4 sub-groups, there was a graded reduction in LVEF and FR, and an increase in age and all–cause mortality.

Conclusions

Classification of aortic stenosis based on flow-gradient patterns, shows important differences in the demographic profile and clinical outcome among the 4 groups. Classical NFHG AS was associated with the highest rate of AVI and lowest all-cause mortality compared to the 3 discordant flow-gradient subtypes. The LFLG group had the lowest AVI rates and worst outcome.

Funding Acknowledgement

Type of funding source: None

A patient with pleuritic chest pain and abnormal blood clotting tests

We present the case of a 58 year old man who developed pleuritic chest while an in-patient; investigations revealed pulmonary embolism, despite a significantly raised Activated Partial Thromboplastin Time (APTT), which was subsequently attributed to Antiphospholipid syndrome (APS). The diagnosis and initial management of APS in the acute setting is discussed.