The emerging role of exercise testing and stress echocardiography in valvular heart disease

Prognostic impact of vasopressor test in transcatheter edge-to-edge repair of secondary mitral regurgitation: The PETIT study

BACKGROUND

Vasopressor test (VPT) might be useful in patients with functional mitral regurgitation (MR) and left ventricular dysfunction (MITRA-FR-like patients) during transcatheter edge-to-edge repair (TEER).

AIMS

We aimed to evaluate the prognostic impact of VPT.

METHODS

MR treated with TEER were included in a multicenter prospective registry. VPT was used intraprocedurally in patients with left ventricular dysfunction and/or hypotension. The 1-year echocardiographic and clinical outcomes were compared according to the use of VPT. The primary endpoint was a combination of mortality + heart failure (HF) readmission at 1-year.

RESULTS

A total of 1115 patients were included, mean age was 72.8 ± 10.5 years and 30.4% were women. VPT was performed in 128 subjects (11.5%), more often in critically ill patients with biventricular dysfunction. Postprocedurally the VPT group had greater rate of MR ≥ 2+ (46.9% vs. 31.7%, p = 0.003) despite greater number of devices (≥2 clips, 52% vs. 40.6 p = 0.008) and device repositioning or new clip in 12.5%. At 1-year, the primary endpoint occurred more often in the VPT group (27.3% vs. 16.9%, p = 0.002) as well as all-cause mortality (21.9% vs. 8.1%, p ≤ 0.001) but no differences existed in HF readmission rate (14.8% vs. 13.2%, p = 0.610), cardiovascular mortality (4.4% vs. 3.9%, p = 0.713) or residual MR ≥ 2+ (51.1% vs 51.7%, p = 0.371).

CONCLUSIONS

Dynamic evaluation of MR during TEER procedure through VPT was performed in patients with worse baseline risk who also presented higher all-cause mortality at 1-year follow-up. However, 1-year residual MR, cardiovascular mortality and HF readmission rate remained comparable suggesting that VPT might help in the management of MITRA-FR-like patients.

Changes in exercise stress echocardiographic parameters before and after transcatheter mitral valve edge-to-edge repair

The safety and feasibility are still not well known for exercise-induced mitral regurgitation (MR). This study is aimed to assess and compare the hemodynamic and symptomatic changes in patients with significant secondary MR during exercise stress echocardiography (ESE) before and after transcatheter edge-to-edge repair (TEER). The study included a total of 15 patients with secondary MR who underwent ESE before and after TEER using the MitraClip system (Abbott, Abbott Park, IL, USA). Echocardiographic data of ESE were collected both before the procedure and during the follow-up visit at 3 months. During the one-year postoperative observation period, the rate of readmission due to heart failure was 13% (n = 2), with no recorded fatalities. Although no significant differences of ESE data were observed in exercise-induced pulmonary hypertension or cardiac output before and after the repair, the severity of MR was significantly improved after the procedure, both at rest (2 [2-3] vs. 1 [1-2], p = 0.0125) and during ESE (3 [3-3] vs. 1 [1-1], p < 0.0001). Furthermore, the New York Heart Association Functional Classification was improved (3 [3-3] vs. 1 [1-1], p < 0.0001) after treatment. For a supplemental analysis, MR during ESE was significantly improved not only in cases with atrial secondary MR but also in ventricular secondary MR. Transcatheter edge-to-edge repair for exercise-induced MR resulted in a significant improvement in postoperative MR severity and subjective symptoms. These results are novel, as they have not been extensively reported previously, particularly among Japanese patients.

Stress echocardiography in valvular heart disease

Valvular heart disease (VHD) has been a significant health problem, particularly in developed countries, in relation to the aging population. Recent developments in the management of VHD require a more accurate assessment of disease severity to determine the need for transcatheter interventions or open heart surgery. Stress echocardiography is a crucial imaging modality for identifying the underlying pathology of VHD. Optimal administration of exercise or intravenous drugs may reveal hemodynamic abnormalities under stress without posing an invasive risk. Therefore, the implementation of stress echocardiography is recommended for determining interventional indications and risk stratification in mitral regurgitation and aortic stenosis. In addition, recent evidence has accumulated regarding the usefulness of stress echocardiography in various conditions including mitral stenosis, aortic regurgitation, and post-interventional VHD. Here, we summarize the current evidence and future perspectives on stress echocardiography in VHD.

ABCDEG Stress Echocardiography in Aortic Stenosis

Rest and stress echocardiography (SE) plays a pivotal role in the evaluation of valvular heart disease. The use of SE is recommended in valvular heart disease when there is a mismatch between resting transthoracic echocardiography findings and symptoms. In aortic stenosis (AS), rest echocardiographic analysis is a stepwise approach that begins with the evaluation of aortic valve morphology and proceeds to the measurement of the transvalvular aortic gradient and aortic valve area (AVA) using continuity equations or planimetry. The presence of the following three criteria suggests severe AS: AVA < 1.0 cm2, a peak velocity > 4.0 m/s, or a mean gradient > 40 mmHg. However, in approximately one in three cases, we can observe a discordant AVA < 1 cm2 with a peak velocity < 4.0 m/s or a mean gradient <40 mmHg. This is due to reduced transvalvular flow associated with LV systolic dysfunction (LVEF < 50%) defined as "classical" low-flow low-gradient (LFLG) AS or normal LVEF "paradoxical" LFLG AS. SE has an established role in evaluating LV contractile reserve (CR) patients with reduced LVEF. In classical LFLG AS, LV CR distinguished pseudo-severe AS from truly severe AS. Some observational data suggest that long-term prognosis in asymptomatic severe AS may not be as favorable as previously thought, offering a window of opportunity for intervention prior to the onset of symptoms. Therefore, guidelines recommend evaluating asymptomatic AS with exercise stress in physically active patients, particularly those younger than 70 years, and symptomatic classical LFLG severe AS with low-dose dobutamine SE. A comprehensive SE assessment includes evaluating valve function (gradients), the global systolic function of the LV, and pulmonary congestion. This assessment integrates considerations of blood pressure response, chronotropic reserve, and symptoms. StressEcho 2030 is a prospective, large-scale study that employs a comprehensive protocol (ABCDEG) to analyze the clinical and echocardiographic phenotypes of AS, capturing various vulnerability sources which support stress echo-driven treatment strategies.

Modelling blood flow in patients with heart valve disease using deep learning: A computationally efficient method to expand diagnostic capabilities in clinical routine

Introduction

The computational modelling of blood flow is known to provide vital hemodynamic parameters for diagnosis and treatment-support for patients with valvular heart disease. However, most diagnosis/treatment-support solutions based on flow modelling proposed utilize time- and resource-intensive computational fluid dynamics (CFD) and are therefore difficult to implement into clinical practice. In contrast, deep learning (DL) algorithms provide results quickly with little need for computational power. Thus, modelling blood flow with DL instead of CFD may substantially enhances the usability of flow modelling-based diagnosis/treatment support in clinical routine. In this study, we propose a DL-based approach to compute pressure and wall-shear-stress (WSS) in the aorta and aortic valve of patients with aortic stenosis (AS).

Methods

A total of 103 individual surface models of the aorta and aortic valve were constructed from computed tomography data of AS patients. Based on these surface models, a total of 267 patient-specific, steady-state CFD simulations of aortic flow under various flow rates were performed. Using this simulation data, an artificial neural network (ANN) was trained to compute spatially resolved pressure and WSS using a centerline-based representation. An unseen test subset of 23 cases was used to compare both methods.

Results

ANN and CFD-based computations agreed well with a median relative difference between both methods of 6.0% for pressure and 4.9% for wall-shear-stress. Demonstrating the ability of DL to compute clinically relevant hemodynamic parameters for AS patients, this work presents a possible solution to facilitate the introduction of modelling-based treatment support into clinical practice.

Exercise Testing in Aortic Stenosis: Safety, Tolerability, Clinical Benefits and Prognostic Value

Background: Routine exercise testing in asymptomatic patients with valvular heart disease (VHD) better classifies the hemodynamic severity of valve stenosis or regurgitation, and describes the symptomatic status and functional capacity of the patient. This is crucial for planned surveillance and optimal timing of surgery, particularly for aortic stenosis (AS), because once symptoms occur, there is a sharp increase in the risk of sudden death unless valve intervention is performed. Purpose: To conduct a focused clinical review on the benefits of exercise testing in patients with AS. Methods: The electronic database PubMed was systematically searched for relevant retrospective and prospective cohort studies reporting on the safety, feasibility and tolerability of exercise testing in VHD, with a special focus on AS. Results and conclusions: In patients with significant AS, exercise testing is safe, feasible and reveals symptoms in a significant proportion of patients. In addition, serial testing has incremental prognostic value over a baseline test alone. Exercise testing in patients with AS is underused and should be performed routinely to refine the hemodynamic severity of AS.

Exercise stress echocardiography: Where are we now?

Exercise stress echocardiography (ESE) is a widely used diagnostic test in cardiology departments. ESE is mainly used to study patients with coronary artery disease; however, it has increasingly been used in other clinical scenarios including valve pathology, congenital heart disease, hypertrophic and dilated cardiomyopathies, athlete evaluations, diastolic function evaluation, and pulmonary circulation study. In our laboratories, we use an established methodology in which cardiac function is evaluated while exercising on a treadmill. After completing the exercise regimen, patients remain in a standing position or lie down on the left lateral decubitus, depending on the clinical questions to be answered for further evaluation. This method increases the quality and quantity of information obtained. Here, we present the various methods of exercise stress echocardiography and our experience in many clinical arenas in detail. We also present alternatives to ESE that may be used and their advantages and disadvantages. We review recent advances in ESE and future directions for this established method in the study of cardiac patients and underline the advantage of using a diagnostic tool that is radiation-free.

Cardiac Complications in Pregnant Women With Isolated Mitral Stenosis and Their Association With Echocardiographic Changes During Pregnancy

In women with mitral stenosis (MS), mitral valve gradients and right ventricular systolic pressure (RVSP) can increase in response to the physiologic stress of pregnancy. The prognostic significance of these echocardiographic changes has not been well studied. Pregnancy outcomes and serial echocardiograms were collected in women with MS prospectively recruited as part of a larger study on pregnancy outcomes. Third trimester echocardiograms were compared with baseline echocardiograms. Changes in mitral valve area (MVA), transmitral mean gradient (MG), and RVSP during pregnancy and their relationship to adverse cardiac events (CE) were examined. Fifty-six pregnancies in 47 women with MS were included. The MVA did not change during pregnancy (1.6 ± 0.6 cm² at baseline vs 1.7 ± 0.6 cm² in the third trimester, p = 0.46). There was an increase in the MG (8 ± 3 vs 11 ± 6 mm Hg, p <0.001) and the RVSP (39 ± 14 vs 47 ± 20 mm Hg, p <0.001) during the third trimester. Adverse CE occurred in 45% (25/56) of pregnancies. CE were associated with baseline MG>10 mm Hg, baseline RVSP >40 mm Hg, third-trimester MG>10 mm Hg, and RVSP >40 mm Hg. Women with mitral valve MG ≤10 mm Hg who had a normal RVSP at baseline and in the third trimester were at lowest risk for CE (11%) with a negative predictive value of 89%. In conclusion, baseline echocardiographic assessment of MS severity as well as changing echocardiographic parameters during pregnancy can help identify women at risk for cardiac complications during pregnancy.

Manual zur Indikation und Durchführung spezieller echokardiographischer Anwendungen

Das zweite Manual zur Indikation und Durchführung der Echokardiographie bezieht sich auf spezifische Anwendungen der Echokardiographie und besondere Fragestellungen bei speziellen Patientengruppen. Dabei stehen v. a. praktische Aspekte im Vordergrund. Methodisch etabliert sind die transösophageale Echokardiographie, die Stressechokardiographie und die Kontrastechokardiographie. Bei nahezu allen echokardiographischen Untersuchungen spielen aktuell 3‑D-Echokardiographie und Deformationsbildgebung eine Rolle. Das gesamte Spektrum der echokardiographischen Möglichkeiten wird derzeit in Notfall- und Intensivmedizin, bei der Überwachung und Führung von Katheterinterventionen, bei strukturellen Herzerkrankungen, bei herzchirurgischen Operationen, bei der Nachsorge von kardialen Unterstützungssystemen, bei kongenitalen Vitien im Erwachsenenalter und bei der Versorgung von hochinfektiösen Patienten in Pandemiezeiten angewandt. Die diagnostischen Fortschritte der konventionellen und modernen echokardiographischen Anwendungen stehen im Fokus dieses Manuals. Die 3‑D-Echokardiographie zur Charakterisierung der kardialen Morphologie und die Deformationsbildgebung zur Objektivierung der kardialen Funktion sind bei vielen Indikationen im klinischen Alltag etabliert. Die Stressechokardiographie zur Ischämie‑, Vitalitäts- und Vitiendiagnostik, die Bestimmung der koronaren Flussreserve und die Kontrastechokardiographie bei der linksventrikulären Wandbewegungsanalyse und kardialen Tumordetektion finden zunehmend klinische Anwendung. Wie für die konventionelle Echokardiographie im ersten Manual der Echokardiographie 2009 beschrieben, erfordert der Einsatz moderner echokardiographischer Verfahren die standardisierte Dokumentation und Akquisition bestimmter Bildsequenzen bei optimierter Geräteeinstellung, da korrekte und reproduzierbare Auswertungen nur bei guter Bildqualität möglich sind.

The effect of treatment with pimobendan in dogs with preclinical mitral valve disease - a placebo-controlled double-blinded crossover study

Background

Pimobendan is a widely used medication for the treatment of dogs with congestive heart failure (CHF) and preclinical degenerative mitral valve disease (DMVD) with cardiomegaly. The benefit of a treatment in dogs with preclinical DMVD but without cardiomegaly has not yet been elucidated. Some positive effects concerning life quality and a decrease in cardiac biomarkers could be verified. This study aimed to further investigate these results using a placebo-controlled double-blinded crossover design. Out of a total of 15 dogs, eight were allocated to sequence-group AB, in which dogs received pimobendan (A) during the first treatment period and placebo (B) during the second period. Accordingly, sequence-group BA was treated first with placebo followed by pimobendan. Each treatment period lasted six months and included a baseline investigation and follow-ups after 90 and 180 days. The investigations included a questionnaire completed by the owners, echocardiographic examination, and measurements of NT-proBNP, cTnI and lactate before and after a standardised submaximal exercise test.

Results

NT-proBNP values decreased significantly during the treatment period with pimobendan, and the post-exercise increase was attenuated at day 180. No significant treatment effects could be verified for cTnI and lactate, neither pre- nor post-exercise. Left ventricular size decreased under treatment, whereas no significant changes in left atrial size were detected. The owners described their dogs under treatment with pimobendan as being more active at day 90 (11/15) and day 180 (12/15). Those animals treated with placebo were described as being more active at day 90 (2/15) and day 180 (5/15).

Conclusions

Pimobendan had reducing effects on the concentrations of pre- and post-exercise cardiac biomarkers and the size of the left ventricle in dogs with DMVD ACVIM B1. Exercise testing in addition to an assessment of cardiac biomarkers might improve the decision when to initiate pimobendan treatment in dogs with DMVD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03014-5.

Higher rate of aortic stenosis progression in patients with bicuspid versus tricuspid aortic valve - A single center experience

PURPOSE

We sought to investigate aortic stenosis (AS) progression rate (pr) with the comparison between bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV) morphology.

MATERIALS AND METHODS

We compared ASpr in patients with BAV and TAV examined by transthoracic echocardiography (TTE) in the years 2004-2019.

RESULTS

Data from 363 TTEs in 161 AS patients (median age 70 [61-77] years; 63% men; 25% with BAV; 20% with severe AS) performed at different time points (median time interval 10 months) was analyzed. We assessed changes of AS severity with peak velocity through aortic valve (Vmax), mean/peak pressure gradients (MG/PG), aortic valve area by planimetry and continuity equation (AVAce). We compared pr (defined as parameter change per year) between the BAV and the TAV groups. BAV patients showed faster ASpr with odds ratio 3.467 and 95% confidence intervals 1.36 to 8.86, moreover, expressed as a quicker AVAce decrease 0 (-0.4-0.0) in the BAV vs. 0 (-0.15 - 0.0) cm²/year in the TAV group, p ​= ​0.02. Furthermore, in BAV, female sex was associated with lower ASpr (p ​= ​0.01), and in the whole group a larger aortic diameter was a predictor of faster progression (p ​< ​0.001).

CONCLUSION

The ASpr, expressed as a decrease in the AVAce, was faster in BAV. Moreover, ASpr depends on both: valve morphology being faster in BAV and Vmax increase. Furthermore, the female sex was related to slower pace of AVA reduction in BAV subgroup whereas the larger baseline aortic diameter associated to faster AS progression in the whole studied group.

Updated knowledge and practical implementations of stress echocardiography in ischemic and non-ischemic cardiac diseases: an expert consensus of the Working Group of Echocardiography of the Hellenic Society of Cardiology

Stress echocardiography (SE) is a well-established and valid technique, widely-used for the diagnostic evaluation of patients with ischemic and non-ischemic cardiac diseases. This statement of the Echocardiography Working Group of the Hellenic Society of Cardiology summarizes the consensus of the writing group regarding the applications of SE, based on the expertise of their members and on a critical review of current medical literature. The main objectives of the consensus document include a comprehensive review of SE methodology and training, focusing on the preparation, the protocols used and the analysis of the SE images and an updated, evidence-based knowledge about SE applications on ischemic and non-ischemic heart diseases, such as in cardiomyopathies, heart failure and valvular heart disease.

Global longitudinal strain to determine optimal timing for surgery in primary mitral regurgitation: A systematic review

BACKGROUND

Primary mitral regurgitation (PMR) results in adverse remodeling changes and left ventricular (LV) dysfunction. Assessing LV function has prognostic value in predicting morbidity and mortality. Indications for surgery include parameters such as LV ejection fraction (LVEF) and systolic dimensions. Current guidelines are limited in identifying patients at optimal time for surgery. Impaired postoperative LVEF indicates poor prognostic outcomes and subsequent heart failure. Global longitudinal strain (GLS) via speckle tracking echocardiography (STE) presents as a promising parameter to detect subclinical dysfunction in asymptomatic patients.

METHODS

Following PRISMA guidelines, a literature search was conducted with Cochrane Library, PudMed, SCOPUS, and Web of Science. Key MeSH terms included "mitral regurgitation," "mitral valve insufficiency," "global longitudinal strain," "deformation," "LV-GLS," and "GLS." Inclusion criteria included (1) patients with severe PMR, (2) mixed population of symptomatic and asymptomatic patients, (3) standardized methods in assessing LV systolic function using 2D-STE, (4) valve repair or replacement surgery, and (5) patient outcomes measured after surgery. Search returned 234 papers, 12 of which met the inclusion criteria and were subsequently reviewed.

RESULTS

Baseline GLS is an independent predictor of postoperative outcomes, ranging from -17.9 to -21.7% GLS. A significant negative correlation was observed between preoperative GLS and postoperative LVEF. Impaired baseline GLS was associated with higher mortality rates. Better long-term survival rates were seen in patients who underwent early surgery.

CONCLUSION

GLS shows sensitivity in predicting long-term postoperative outcomes. Further analysis is required to determine preoperative GLS threshold to identify asymptomatic patients at the optimal time for mitral valve surgery.

Selection of the Optimal Candidate to MitraClip for Secondary Mitral Regurgitation: Beyond Mitral Valve Morphology

Secondary mitral regurgitation (MR) occurs despite structurally normal valve apparatus due to an underlying disease of the myocardium leading to disruption of the balance between tethering and closing forces with ensuing failure of leaflet coaptation. In patients with heart failure (HF) and left ventricular dysfunction, secondary MR is independently associated with poor outcome, yet prognostic benefits related to the correction of MR have remained elusive. Surgery is not recommended for the correction of secondary MR outside coronary artery bypass grafting. Percutaneous mitral valve repair (PMVR) with MitraClip implantation has recently evolved as a new transcatheter treatment option of inoperable or high-risk patients with severe MR, with promising results supporting the extension of guideline recommendations. MitraClip is highly effective in reducing secondary MR in HF patients. However, the derived clinical benefit is still controversial as two randomized trials directly comparing PMVR vs. optimal medical therapy in severe secondary MR yielded virtually opposite conclusions. We reviewed current evidence to identify predictors of PMVR-related outcomes in secondary MR useful to improve the timing and the selection of patients who would derive maximal benefit from MitraClip intervention. Beyond mitral valve anatomy, optimal candidate selection should rely on a comprehensive diagnostic workup and a fine-tuned risk stratification process aimed at (i) recognizing the substantial heterogeneity of secondary MR and its complex interaction with the myocardium, (ii) foreseeing hemodynamic consequences of PMVR, (iii) anticipating futility and (iv) improving symptoms, quality of life and overall survival.

Dynamic handgrip exercise for the evaluation of mitral valve regurgitation: an echocardiographic study to identify exertion induced severe mitral regurgitation

Handgrip exercise (HG) has been occasionally used as a stress test in echocardiography. The effect of HG on mitral regurgitation (MR) is not well known. This study aims to evaluate this effect and the possible role of HG in the echocardiographic evaluation of MR. 722 patients with MR were included (18% primary, 82% secondary disease). We calculated effective regurgitant orifice area (EROA) and regurgitant volume (RVOL) at rest and during dynamic HG. Increase in MR was defined as any increase in EROA or RVOL. We analyzed the data to identify possible associations between clinical or echocardiographic parameters and the effect of HG on MR. MR increased during dynamic HG in 390 of 722 patients (54%) (∆EROA = 25%, ∆RVOL = 27%). Increase of regurgitation occurred in 66 of 132 patients with primary MR (50%) and in 324 of 580 patients with secondary MR (55%). This increase was associated with larger baseline EROA and RVOL, but it was independent from other clinical or echocardiographic parameters. In secondary MR, dynamic HG led to a reclassification of regurgitation severity from non-severe at rest to severe MR during HG in 104 of 375 patients (28%). There was a significant association between this upgrade in MR classification and higher New York Heart Association (NYHA) class (OR 1.486, 95%-CI 1.138-1.940, p = 0.004). Dynamic HG exercise increases MR in about half of patients independent of the etiology. Dynamic HG may be used to identify symptomatic patients with non-severe secondary MR at rest but severe MR during exercise.

Clinical implications of exercise-induced regional wall motion abnormalities in significant aortic regurgitation

BACKGROUND

Significant aortic regurgitation (AR) is sometimes accompanied by regional wall motion abnormalities (RWMA) during exercise stress echocardiography. The aim of this study was to estimate the association between RWMA after exercise and in the presence of significant AR in patients with coronary artery disease (CAD) or volume overload and to predict the eventual need for aortic valve replacement (AVR).

METHODS AND RESULTS

We retrospectively reviewed 182 patients with significant AR who underwent exercise echocardiography. In addition, we investigated patients with AR who underwent coronary angiography (CAG) or coronary computed tomography angiography (CCTA) and were diagnosed with CAD. The presence of RWMA after exercise was defined as newly developed RWMA after exercise and included all changes in wall motion. Patients were divided into two groups according to the presence of RWMA after exercise: the RWMA group (n = 42) and non-RWMA group (n = 140). In the RWMA group, 31 patients (73.8%) underwent coronary artery evaluation by CAG or CCTA. Only two patients in the RWMA group were diagnosed with current CAD and underwent percutaneous coronary intervention. Patients with RWMA were older (61.6 ± 10.8 vs 52.0 ± 13.7 years, P < .001), had more severe AR (54.8% vs 32.9%), and underwent AVR more frequently (40.5% vs 14.3%, P = .001) than patients without RWMA. METs (odds ratio [OR], 0.796; P = .019), difference between rest and postexercise left ventricular end-diastolic volume (OR, 0.967; P = .001), and the difference between pre- and postexercise left ventricular end-systolic volume (OR, 1.113; P < .001) were identified as independent factors associated with RWMA after exercise according to multivariable logistic regression analysis. The majority of wall motion changes were seen in the lateral and inferior segments, and the locations of wall motion changes were relatively consistent with the direction of the AR jet. The relationship between RWMA after exercise and time to AVR was investigated by simple linear regression (hazard ratio [HR], 3.402; P < .001). After adjusting for baseline parameters of diastolic blood pressure, left ventricular end-systolic dimension (LVESD), aorta size, deceleration time, and METs, the presence of RWMA after exercise was not predictive of time to AVR (HR, 1.106; P = .81). On the other hand, without forcible entry of RWMA after exercise, LVESD (HR, 1.119; P < .001) and METs (HR, 0.828; P = .006) independently predicted the eventual need for AVR as an outcome.

CONCLUSION

The degree of change in wall motion from rest to exercise in those with significant AR was not correlated with CAD, but was correlated with the severity of volume overload and exercise-induced preload changes, as well as the direction of the AR jet. In addition, RWMA after exercise had no role in predicting the need for AVR.

Timing of intervention in asymptomatic patients with valvular heart disease

Current management of valvular heart disease (VHD) seeks to optimize long-term outcome by timely intervention. Recommendations for treatment of patients with symptoms due to severe valvular disease are based on a foundation of solid evidence. However, when to intervene in asymptomatic patients remains controversial and decision requires careful individual weighing of the potential benefits against the risk of intervention and its long-term consequences. The primary rationale for earlier intervention is prevention of irreversible left ventricular (LV) myocardial changes that might result in later clinical symptoms and adverse cardiac events. A number of outcome predictors have been identified that facilitate decision-making. This review summarizes current recommendations and discusses recently published data that challenge them suggesting even earlier intervention. In adults with asymptomatic aortic stenosis (AS), emerging risk markers include very severe valve obstruction, elevated serum natriuretic peptide levels, and imaging evidence of myocardial fibrosis or increased extracellular myocardial volume. Currently, transcatheter aortic valve implantation (TAVI) is not recommended for treatment of asymptomatic severe AS although this may change in the future. In patients with aortic regurgitation (AR), the potential benefit of early intervention in preventing LV dilation and dysfunction must be balanced against the long-term risk of a prosthetic valve, a particular concern because severe AR often occurs in younger patients with a congenital bicuspid valve. In patients with mitral stenosis, the option of transcatheter mitral balloon valvotomy tilts the balance towards earlier intervention to prevent atrial fibrillation, embolic events, and pulmonary hypertension. When chronic severe mitral regurgitation is due to mitral valve prolapse, anatomic features consistent with a high likelihood of a successful and durable valve repair favour early intervention. The optimal timing of intervention in adults with VHD is a constantly changing threshold that depends not only on the severity of valve disease but also on the safety, efficacy, and long-term durability of our treatment options.

Discordant Echocardiographic Grading in Low Gradient Aortic Stenosis (DEGAS Study) From the Italian Society of Echocardiography and Cardiovascular Imaging Research Network: Rationale and Study Design

Background

Low-gradient aortic stenosis (LG-AS) is characterized by the combination of an aortic valve area compatible with severe stenosis and a low transvalvular mean gradient with low-flow state (i.e., indexed stroke volume <35 mL/m²) in the presence of reduced (classical low-flow AS) or preserved (paradoxical low-flow AS) ejection fraction. Furthermore, the occurrence of a normal-flow LG-AS is still advocated by many authors. Within this diagnostic complexity, the diagnosis of severe AS remains challenging.

Objective

The general objective of the Discordant Echocardiographic Grading in Low-gradient AS (DEGAS Study) study will be to assess the prevalence of true severe AS in this population and validate new parameters to improve the assessment and the clinical decision-making in patients with LG-AS.

Methods and Analyses

The DEGAS Study of the Italian Society of Echocardiography and Cardiovascular Imaging is a prospective, multicenter, observational diagnostic study that will enroll consecutively adult patients with LG-AS over 2 years. AS severity will be ideally confirmed by a multimodality approach, but only the quantification of calcium score by multidetector computed tomography will be mandatory. The primary clinical outcome variable will be 12-month all-cause mortality. The secondary outcome variables will be (i) 30-day mortality (for patients treated by Surgical aortic valve replacement or TAVR); (ii) 12-month cardiovascular mortality; (iii) 12-month new major cardiovascular events such as myocardial infarction, stroke, vascular complications, and rehospitalization for heart failure; and (iv) composite endpoint of cardiovascular mortality and hospitalization for heart failure. Data collection will take place through a web platform (REDCap), absolutely secure based on current standards concerning the ethical requirements and data integrity.

Exercise echocardiography in aortic stenosis with preserved ejection fraction

The appropriate timing of intervention and follow-up in asymptomatic patients with aortic stenosis remains controversial. Risk stratification is a key, especially with the use of a multimodality imaging approach, including exercise stress echocardiography. This review focuses on the use of exercise echocardiography in asymptomatic patients with moderate and severe aortic stenosis with preserved left ventricular ejection fraction. It describes the exercise echocardiography protocol, parameters to be evaluated, and its role in guiding the timing of intervention and follow-up in these patients.

Secondary mitral regurgitation: pathophysiology, proportionality and prognosis

Secondary mitral regurgitation (SMR) occurs as a result of multifactorial left atrioventricular dysfunction and maleficent remodelling. It is the most common and undertreated form of mitral regurgitation (MR) and is associated with a very poor prognosis. Whether SMR is a bystander reflecting the severity of the cardiomyopathy disease process has long been the subject of debate. Studies suggest that SMR is an independent driver of prognosis in patients with an intermediate heart failure (HF) phenotype and not those with advanced HF. There is also no universal agreement regarding the quantitative thresholds defining severe SMR and indeed there are challenges with echocardiographic quantification. Until recently, no surgical or transcatheter intervention for SMR had demonstrated prognostic benefit, in contrast with HF medical therapy and cardiac resynchronisation therapy. In 2018, the first two randomised controlled trials (RCTs) of edge-to-edge transcatheter mitral valve repair versus guideline-directed medical therapy in HF (Percutaneous Repair with the MitraClip Device for Severe (MITRA-FR), Transcather mitral valve repair in patients with heart failure (COAPT)) reported contrasting yet complimentary results. Unlike in MITRA-FR, COAPT demonstrated significant prognostic benefit, largely attributed to the selection of patients with disproportionately severe MR relative to their HF phenotype. Consequently, quantifying the degree of SMR in relation to left ventricular volume may be a useful discriminator in predicting the success of transcatheter intervention. The challenge going forward is the identification and validation of such parameters while in parallel maintaining a heart-team guided holistic approach.

Functional Mitral Regurgitation in Heart Failure

Functional mitral regurgitation (FMR) in the setting of left ventricular (LV) dysfunction and heart failure portends a poor prognosis. Guideline-directed medical therapy remains the cornerstone of initial treatment, with emphasis placed on treatment of the underlying LV dysfunction, as FMR is a secondary phenomenon and a disease due to LV remodeling. Surgical correction of FMR is controversial because it typically does not address the underlying mechanism and etiology of the condition. However, new, minimally invasive transcatheter therapies, in particular the MitraClip system, have shown promise in the treatment of FMR in selected patients. This review will summarize the pathophysiology underlying FMR, the prognosis of patients with heart failure and FMR, and the various medical and procedural treatment options currently available and under investigation.

Hemodynamic Characteristics in Significant Symptomatic and Asymptomatic Primary Mitral Valve Regurgitation at Rest and During Exercise

BACKGROUND

In severe asymptomatic primary mitral valve regurgitation without risk factors, surgery strategy is controversial. We sought to clarify whether being symptomatic corresponds to the hemodynamic burden and reduced exercise capacity. A better understanding of this may contribute to optimize timing of surgery.

METHODS AND RESULTS

Subjects with asymptomatic (New York Heart Association functional class I, n=29) or symptomatic (New York Heart Association functional class II and III, n=28) significant primary mitral valve regurgitation (effective regurgitant orifice, ≥0.30 cm²; left ventricular ejection fraction, >60%) were included. Right heart catheterization during rest and exercise, echocardiography, magnetic resonance imaging, and peak oxygen consumption test was performed. Symptomatic subjects had significantly higher pulmonary capillary wedge pressure at rest (14±4 versus 11±3 mm Hg; P=0.003) and at maximal exercise (30±6 versus 25±7 mm Hg; P=0.02) and higher mean pulmonary artery pressure (PAP) at rest (22±7 versus 18±4 mm Hg; P=0.005) and maximal exercise (46±8 versus 39±7 mm Hg; P=0.005) than asymptomatic subjects. Among asymptomatic subjects with normal resting value, exercise testing revealed a systolic PAP >60 mm Hg in 34%. Also the reverse response with minimal increase in pulmonary capillary wedge pressure and mean PAP during exercise was seen, especially in asymptomatic subjects. Among symptomatic subjects, we found a significant inverse correlation between resting mean PAP and left ventricular ejection fraction (r=-0.52; P=0.02) and right ventricular ejection fraction (r=-0.67; P<0.01). Peak oxygen consumption was equal and normal in both groups and correlated with left ventricular stroke volume but not with pulmonary capillary wedge pressure.

CONCLUSIONS

Symptoms in patients with severe mitral valve regurgitation relate to congestion (pulmonary capillary wedge pressure and PAP), but not to peak oxygen consumption, which is determined by forward left ventricular stroke volume. Exercise testing reveals a higher mitral valve regurgitation burden in apparently asymptomatic patients.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02961647.

Hemodynamic Changes During Physiological and Pharmacological Stress Testing in Healthy Subjects, Aortic Stenosis and Aortic Coarctation Patients-A Systematic Review and Meta-Analysis

Introduction: Exercise testing has become a diagnostic standard in the evaluation and management of heart disease. While different methods of exercise and pharmacological stress testing exist, only little is known about their comparability. We aimed to assess hemodynamic changes during dynamic exercise, isometric exercise, and dobutamine stress testing at different stress intensities in healthy subjects and patients with aortic stenosis (AS) and aortic coarctation (CoA).

Methods: A systematic literature search (PROSPERO 2017:CRD42017078608) in MEDLINE of interventional trials was conducted to identify eligible studies providing evidence of changes in hemodynamic parameters under different stress conditions acquired by MRI or echocardiography. A random effects model was used to estimate pooled mean changes in hemodynamics.

Results: One hundred and twenty-eight study arms with a total of 3,139 stress-examinations were included. In healthy subjects/(where available) in AS, pooled mean changes (95% CIs) during light dynamic stress were 31.78 (27.82–35.74) bpm in heart rate (HR) and 6.59 (2.58–10.61) ml in stroke volume (SV). Changes during light pharmacological stress were 13.71 (7.87–19.56)/14.0 (9.82–18.18) bpm in HR, and 5.47 (0.3–10.63)/8.0 (3.82–12.18) ml in SV. Changes during light isometric stress were 18.44 (10.74–26.14)/5.0 (−1.17–11.17) bpm in HR and −4.17 (−14.37–6.03)/−4.0 (−16.43–8.43) ml in SV. Changes during moderate dynamic stress were 49.57 (40.03–59.1)/46.45 (42.63–50.27) bpm in HR and 11.64 (5.87–17.42) ml in SV. During moderate pharmacological stress, changes in HR were 42.83 (36.94–48.72)/18.66 (2.38–34.93) bpm and in SV 6.29 (−2.0–14.58)/13.11 (7.99–18.23) ml. During high intensity dynamic stress changes in HR were 89.31 (81.46–97.17)/55.32 (47.31–63.33) bpm and in SV 21.31 (13.42–29.21)/−0.96 (−5.27–3.35) ml. During high pharmacological stress, changes in HR were 53.58 (36.53–70.64)/42.52 (32.77–52.28) bpm, and in SV 0.98 (−9.32–11.27)/14.06 (−1.62–29.74) ml. HR increase and age were inversely correlated at high stress intensities. In CoA, evidence was limited to single studies.

Conclusion: This systematic review and meta-analysis presents pooled hemodynamic changes under light, moderate and high intensity exercise and pharmacological stress, while considering the potential influence of age. Despite limited availability of comparative studies, the reference values presented in this review allow estimation of the expected individual range of a circulatory response in healthy individuals and patients with AS and may contribute to future study planning and patient-specific models even when stress testing is contraindicated.

Rheumatic Mitral Valve Stenosis: Diagnosis and Treatment Options

PURPOSE OF REVIEW

This review provides an update on rheumatic mitral stenosis. Acute rheumatic fever (RF), the sequela of group A β-hemolytic streptococcal infection, is the major etiology for mitral stenosis (MS).

RECENT FINDINGS

While the incidence of acute RF in the Western world had substantially declined over the past five decades, this trend is reversing due to immigration from non-industrialized countries where rheumatic heart disease (RHD) is higher. Pre-procedural evaluation for treatment of MS using a multimodality approach with 2D and 3D transthoracic and transesophageal echo, stress echo, cardiac CT scanning, and cardiac MRI as well as hemodynamic assessment by cardiac catheterization is discussed. The current methods of percutaneous mitral balloon commissurotomy (PMBC) and surgery are also discussed. New data on long-term follow-up after PMBC is also presented. For severe rheumatic MS, medical therapy is ineffective and definitive therapy entails PMBC in patients with suitable morphological mitral valve (MV) characteristics, or surgery. As procedural outcomes depend heavily on appropriate case selection, definitive imaging and interpretation are crucial. It is also important to understand the indications as well as morphological MV characteristics to identify the appropriate treatment with PMBC or surgery.

Quest for cardiovascular interventions: precise modeling and 3D printing of heart valves

Digitalization of health care practices is substantially manifesting itself as an effective tool to diagnose and rectify complex cardiovascular abnormalities. For cardiovascular abnormalities, precise non-invasive imaging interventions are being used to develop patient specific diagnosis and surgical planning. Concurrently, pre surgical 3D simulation and computational modeling are aiding in the effective surgery and understanding of valve biomechanics, respectively. Consequently, 3D printing of patient specific valves that can mimic the original one will become an effective outbreak for valvular problems. Printing of these patient-specific tissues or organ components is becoming a viable option owing to the advances in biomaterials and additive manufacturing techniques. These additive manufacturing techniques are receiving a full-fledged support from burgeoning field of computational fluid dynamics, digital image processing, artificial intelligence, and continuum mechanics during their optimization and implementation. Further, studies at cellular and molecular biomechanics have enriched our understanding of biomechanical factors resulting in valvular heart diseases. Hence, the knowledge generated can guide us during the design and synthesis of biomaterials to develop superior extra cellular matrix, mimicking materials that can be used as a bioink for 3D printing of organs and tissues. With this notion, we have reviewed current opportunities and challenges in the diagnosis and treatment of heart valve abnormalities through patient-specific valve design via tissue engineering and 3D bioprinting. These valves can replace diseased valves by preserving homogeneity and individuality of the patients.

Use of echocardiograms in the Medicare population: a diagnostic tool in the fight against severe aortic stenosis

AIM

To estimate undiagnosed aortic stenosis (AS) in the Medicare population.

METHODS

Patients enrolled (2011-2014) were eligible. After criteria were applied, time zero was the first record of an echocardiogram (ECHO) for the ECHO-AS cohort and randomly assigned for the no-ECHO cohort. The ECHO-AS cohort was propensity matched to patients in the no-ECHO cohort, and survival analysis was performed.

RESULTS

Of the 854,493 (25%) patients who received an ECHO, 1 in 4 were diagnosed with AS. After propensity matching, the no-ECHO cohort who died, almost half (49%) had a record of a cardiovascular event prior to their death. The no-ECHO cohort had statistically significant (p = 0.003) higher risk of death than their ECHO-AS counterparts.

CONCLUSION

In the Medicare population, patients aged 65 years or older, with increased risk factors for and symptoms common in AS patients, should be considered for diagnostic ECHOs.

Contemporaneous management of valvular heart disease and aortopathy in aircrew

Valvular heart disease (VHD) is highly relevant in the aircrew population as it may limit appropriate augmentation of cardiac output in high-performance flying and predispose to arrhythmia. Aircrew with VHD require careful long-term follow-up to ensure that they can fly if it is safe and appropriate for them to do so. Anything greater than mild stenotic valve disease and/or moderate or greater regurgitation is usually associated with flight restrictions. Associated features of arrhythmia, systolic dysfunction, thromboembolism and chamber dilatation indicate additional risk and will usually require more stringent restrictions. The use of appropriate cardiac imaging, along with routine ambulatory cardiac monitoring, is mandatory in aircrew with VHD.Aortopathy in aircrew may be found in isolation or, more commonly, associated with bicuspid aortic valve disease. Progression rates are unpredictable, but as the diameter of the vessel increases, the associated risk of dissection also increases. Restrictions on aircrew duties, particularly in the context of high-performance or solo flying, are usually required in those with progressive dilation of the aorta.

MRI assessment of aortic flow in patients with pulmonary arterial hypertension in response to exercise

Background

While primarily a right heart disease, pulmonary arterial hypertension (PAH) can impact left heart function and aortic flow through a shifted interventricular septum from right ventricular pressure overload and reduced left ventricular preload, among other mechanisms. In this study, we used phase contrast (PC) MRI and a modest exercise challenge to examine the effects of PAH on systemic circulation. While exercise challenges are typically performed with ultrasound in the clinic, MRI exercise studies allow for more reproducible image alignment, more accurate flow quantification, and improved tissue contrast.

Methods

Six PAH patients and fifteen healthy controls (8 older age-matched, 7 younger) exercised in the magnet bore with an MRI-compatible exercise device that allowed for scanning immediately following cessation of exercise. PC scans were performed in the ascending aorta during a breath hold immediately after modest exercise to non-invasively measure stroke volume (SV), cardiac output (CO), aortic peak systolic flow (PSF), and aortic wall stiffness via relative area change (RAC).

Results

Images following exercise showed mild blurring, but were high enough quality to allow for segmentation of the aorta. While SV was approximately 30% lower in PAH patients (SV_PAH,rest = 67 ± 16 mL; SV_PAH,stress = 90 ± 42 mL) than age-matched controls (SV_,older,rest = 93 ± 16 mL; SV_older,stress = 133 ± 40 mL) at both rest and following exercise, CO was similar for both groups following exercise (CO_PAH,stress = 10.8 ± 5.7 L/min; CO_older,stress = 11.8 ± 5.0 L/min). This was achieved through a compensatory increase in heart rate in the PAH subjects (74% increase as compared to 29% in age-matched controls). The PAH subjects also demonstrated reduced aortic peak systolic flow relative to the healthy controls (PSF_PAH,_rest = 309 ± 52 mL/s; PSF_older,_rest = 416 ± 114 mL/s; PSF_PAH,_stress = 388 ± 113 mL/s; PSF_older,_stress = 462 ± 176 mL/s). PAH patients and older controls demonstrated stiffer aortic walls when compared to younger controls (RAC_PAH,rest = 0.15 ± 0.05; RAC_older,rest = 0.17 ± 0.05; RAC_young,rest = 0.28 ± 0.08).

Conclusions

PC MRI following a modest exercise challenge was capable of detecting differences in left heart dynamics likely induced from PAH. These results demonstrated that PAH can have a significant influence on systemic flow, even when the patient has no prior left heart disease. Image quantification following exercise could likely be improved in future studies through the implementation of free-breathing or real-time MRI acquisitions.

Trial registration

Retrospectively registered on 02/26/2018 (TRN:NCT03523910).

Timing and mode of intervention for patients with left sided valvular heart disease: an individualized approach

Left sided valvular heart disease poses major impact on life and lifestyle. Medical therapy merely palliates chronic severe valve disease and once symptoms or haemodynamic sequelae appear, life expectancy is markedly truncated. In this article, we review the mechanisms of valve pathology, latest evidence in the quest for pharmacological options, means by which to predict deterioration, and standard and novel treatment options.

Directional Doppler in Cardiology: A 50-Year Journey

In 1968, while cardiologists were focused on cardiac structures imaged by ultrasound, Daniel Kalmanson in Paris, France, devised a new ultrasonic modality, directional continuous-wave Doppler, enabling him to record instantaneous cardiovascular blood flow velocities with recognition of their direction (relative to the transducer) in vessels. An innovative presentation of Doppler data also made velocity traces physiologically understandable. Following the noninvasive study of the arterial and venous beds, flow velocity in the right (1969) and left (1970) cardiac chambers was studied by means of a directional Doppler catheter. The curtain was then raised for the renewal of our pathophysiologic understanding of cardiac dynamics and the adoption of a new methodology. Technological evolution paved the way for clever researchers to pioneer important advances, diversifying the technique. Guided by the early principles, which are still valid in 2018, directional Doppler finally gained acceptance from the entire scientific community.

Can stress echocardiography identify patients who will benefit from percutaneous mitral valve repair?

The aim of the current study was to investigate whether stress echocardiography improves selection of patients who might have clinical benefit from percutaneous mitral valve repair with the MitraClip. In total, 39 patients selected for MitraClip implantation underwent preprocedural low-dose stress (dobutamine or handgrip) echocardiography from which stroke volume, ejection fraction and MR grade were measured. Outcome after MitraClip implantation was determined by New York Heart Association classification and Quality of Life questionnaires. Clinical benefit from MitraClip treatment was defined as survival and NYHA class I–II at 6 months follow-up. In total, 36 patients with a technically successful procedure were included in the analysis (mean age 79 ± 8 years, 47% male, 50% functional MR). Clinical benefit was achieved in 18 patients. All seven patients with MR decreasing during stress remained in NYHA III–IV or died within 6 months, while 62% (18 out of 29) of the patients with stable or increased MR during stress had clinical benefit (p = 0.008). Significant increase in Quality of Life on 4/8 subscales of the RAND Short Form-36 questionnaire was observed: Physical Functioning (p < 0.001), Social Functioning (p < 0.001), Mental Health (p = 0.022) and Vitality (p = 0.026) was seen in patients with an increase in stroke volume during stress echocardiography. Patients with a decreased MR during preprocedural stress echocardiography remained more symptomatic than patients with a stable or increased MR during stress. Stress echocardiography may support patient selection for percutaneous mitral valve repair.

The new clinical standard of integrated quadruple stress echocardiography with ABCD protocol

BACKGROUND

The detection of regional wall motion abnormalities is the cornerstone of stress echocardiography. Today, stress echo shows increasing trends of utilization due to growing concerns for radiation risk, higher cost and stronger environmental impact of competing techniques. However, it has also limitations: underused ability to identify factors of clinical vulnerability outside coronary artery stenosis; operator-dependence; low positivity rate in contemporary populations; intermediate risk associated with a negative test; limited value of wall motion beyond coronary artery disease. Nevertheless, stress echo has potential to adapt to a changing environment and overcome its current limitations.

INTEGRATED-QUADRUPLE STRESS-ECHO

Four parameters now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-stress echo. They are: 1- regional wall motion abnormalities; 2-B-lines measured by lung ultrasound; 3-left ventricular contractile reserve assessed as the stress/rest ratio of force (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D); 4- coronary flow velocity reserve on left anterior descending coronary artery (with color-Doppler guided pulsed wave Doppler). IQ-Stress echo allows a synoptic functional assessment of epicardial coronary artery stenosis (wall motion), lung water (B-lines), myocardial function (left ventricular contractile reserve) and coronary small vessels (coronary flow velocity reserve in mid or distal left anterior descending artery). In "ABCD" protocol, A stands for Asynergy (ischemic vs non-ischemic heart); B for B-lines (wet vs dry lung); C for Contractile reserve (weak vs strong heart); D for Doppler flowmetry (warm vs cold heart, since the hyperemic blood flow increases the local temperature of the myocardium). From the technical (acquisition/analysis) viewpoint and required training, B-lines are the kindergarten, left ventricular contractile reserve the primary (for acquisition) and secondary (for analysis) school, wall motion the university, and coronary flow velocity reserve the PhD program of stress echo.

CONCLUSION

Stress echo is changing. As an old landline telephone with only one function, yesterday stress echo used one sign (regional wall motion abnormalities) for one patient with coronary artery disease. As a versatile smart-phone with multiple applications, stress echo today uses many signs for different pathophysiological and clinical targets. Large scale effectiveness studies are now in progress in the Stress Echo2020 project with the omnivorous "ABCD" protocol.

Safety and efficacy of physiologist-led dobutamine stress echocardiography: experience from a tertiary cardiac centre

Background

Dobutamine stress echocardiography (DSE) services have traditionally been medically led. In some UK institutions, DSE lists are led by physiologists with medical support. In our tertiary cardiac centre at New Cross Hospital (NCH), the DSE service was established by a consultant echocardiographer. Following intensive training and assessment, the Trust approved drug administration by named senior cardiac physiologists. We believe this is the first report of a cardiac physiologist-managed DSE service, including physiologist drug administration. We have assessed the feasibility, safety and validity of this physiologist-led DSE service.

Methods

Retrospective analysis of 333 patients undergoing stress echocardiogram for inducible reversible ischaemia, myocardial viability and valvular heart disease over 6 months. Patients’ case notes review after 18–24 months.

Results

Overall, 92% of all cases (306) were performed by physiologists. In 300 studies, dobutamine was administered. The majority of the referrals were for coronary artery disease (CAD) assessment (281). In 235 cases, the study was uncomplicated. Sixty-seven patients developed dobutamine-related side effects. In 16 cases, complications led to early termination of the study. In two cases, urgent medical review was needed. Of the 281 studies for CAD assessment, 239 were negative for ischaemia, 28 were positive and 14 inconclusive. In 5 out of 28 cases with echocardiogram, evidence of inducible ischaemia, coronary angiography revealed unobstructed coronary arteries.

Conclusion

This study demonstrates the safety and effectiveness of this practice and provides potential for the expansion of the physiologists’ role and physiologist-led DSE services in other hospitals.

Exercise cardiac magnetic resonance imaging: a feasibility study and meta-analysis

Cardiac stress testing improves detection and risk assessment of heart disease. Magnetic resonance imaging (MRI) is the clinical gold-standard for assessing cardiac morphology and function at rest; however, exercise MRI has not been widely adapted for cardiac assessment because of imaging and device limitations. Commercially available magnetic resonance ergometers, together with improved imaging sequences, have overcome many previous limitations, making cardiac stress MRI more feasible. Here, we aimed to demonstrate clinical feasibility and establish the normative, healthy response to supine exercise MRI. Eight young, healthy subjects underwent rest and exercise cinematic imaging to measure left ventricular volumes and ejection fraction. To establish the normative, healthy response to exercise MRI we performed a comprehensive literature review and meta-analysis of existing exercise cardiac MRI studies. Results were pooled using a random effects model to define the left ventricular ejection fraction, end-diastolic, end-systolic, and stroke volume responses. Our proof-of-concept data showed a marked increase in cardiac index with exercise, secondary to an increase in both heart rate and stroke volume. The change in stroke volume was driven by a reduction in end-systolic volume, with no change in end-diastolic volume. These findings were entirely consistent with 17 previous exercise MRI studies (226 individual records), despite differences in imaging approach, ergometer, or exercise type. Taken together, the data herein demonstrate that exercise cardiac MRI is clinically feasible, using commercially available exercise equipment and vendor-provided product sequences and establish the normative, healthy response to exercise MRI.

Clinical use of submaximal treadmill exercise testing and assessments of cardiac biomarkers NT-proBNP and cTnI in dogs with presymptomatic mitral regurgitation

Exercise intolerance is the first symptom of heart disease. Yet an objective and standardised method in canine cardiology to assess exercise capacity in a clinical setting is lacking. In contrast, exercise testing is a powerful diagnostic tool in humans, providing valuable information on prognosis and impact of therapeutic intervention. To investigate whether an exercise test reveals differences between dogs with early stage mitral regurgitation (MR) and dogs without cardiac disease, 12 healthy beagles (healthy group, HG) and 12 dogs with presymptomatic MR (CHIEF B1 / B2, patient group, PG) underwent a six-stage submaximal exercise test (ET) on a motorised treadmill. They trotted in their individual comfort speed for three minutes per stage, first without incline, afterwards increasing it by 4% for every subsequent stage. Blood samples were taken at rest and during two 3-minute breaks in the course of the test. Further samples were taken after the completion of the exercise test and again after a 3-hour recovery period. Measured parameters included heart rate, lactate and the cardiac biomarkers N-terminal pro-B-Type natriuretic peptide and cardiac Troponin I. The test was performed again under the same conditions in the same dogs three weeks after the first trial to evaluate individual repeatability. Cardiac biomarkers increased significantly in both HG and PG in the course of the test. The increase was more pronounced in CHIEF B1 / B2 dogs than in the HG. N-terminal pro-B-Type natriuretic peptide increased from 435 ± 195 to 523 ± 239 pmol/L (HG) and from 690 to 815 pmol/L (PG). cTnI increased from 0.020 to 0.024 ng/mL (HG) and from 0.06 to 0.08 ng/ml (PG). The present study provides a method to assess exercise-induced changes in cardiac biomarkers under clinical conditions. The increase of NT-proBNP and cTnI is more pronounced in dogs with early-stage MR than in healthy dogs. Results indicate that measuring the parameters before and after exercise is adequate and taking blood samples between the different stages of the ET does not provide additional information. Also, stress echocardiography was inconclusive. It can be concluded that exercise testing, especially in combination with measuring cardiac biomarkers, could be a helpful diagnostic tool in canine cardiology.

Multimodality imaging for the quantitative assessment of mitral regurgitation

The natural history of mitral regurgitation (MR) results in significant morbidity and mortality. Innovations in non-invasive imaging have provided new insights into the pathophysiology and quantification of MR, in addition to early detection of left ventricular (LV) dysfunction and prognostic assessment in asymptomatic patients. Transthoracic (TTE) and transesophageal (TOE) echocardiography are the mainstay for diagnosis, assessment and serial surveillance. However, the advance from 2D to 3D imaging leads to improved assessment and characterization of mitral valve (MV) disease. Cardiovascular magnetic resonance (CMR) is increasingly used for MR quantitation and can provide an alternative imaging method if echocardiography is suboptimal or inconclusive. Other techniques such as exercise echocardiography, tissue Doppler imaging and speckle-tracking echocardiography can further offer complementary information on prognosis. This review summarises the current evidence for state-of-the-art cardiovascular imaging for the investigation of MR. Whilst advanced echocardiographic techniques are superior in the evaluation of complex MV anatomy, CMR appears the most accurate technique for the quantification of MR severity. Integration of multimodality imaging for the assessment of MR utilises the advantages of each imaging technique and offers the most comprehensive assessment of MR.

Accuracy of speckle tracking in the context of stress echocardiography in short axis view: An in vitro validation study

Aim

This study aimed to test the accuracy of a speckle tracking algorithm to assess myocardial deformation in a large range of heart rates and strain magnitudes compared to sonomicrometry.

Methods and results

Using a tissue-mimicking phantom with cyclic radial deformation, radial strain derived from speckle tracking (RS-SpT) of the upper segment was assessed in short axis view by conventional echocardiography (Vivid q, GE) and post-processed with clinical software (EchoPAC, GE). RS-SpT was compared with radial strain measured simultaneously by sonomicrometers (RS-SN). Radial strain was assessed with increasing deformation rates (60 to 160 beats/min) and increasing pulsed volumes (50 to 100 ml/beat) to simulate physiological changes occurring during stress echocardiography. There was a significant correlation (R² = 0.978, P <0.001) and a close agreement (bias ± 2SD, 0.39 ± 1.5%) between RS-SpT and RS-SN. For low strain values (<15%), speckle tracking showed a small but significant overestimation of radial strain compared to sonomicrometers. Two-way analysis of variance did not show any significant effect of the deformation rate. For RS-SpT, the feasibility was excellent and the intra- and inter-observer variability were low (the intraclass correlation coefficients were 0.96 and 0.97, respectively).

Conclusions

Speckle tracking demonstrated a good correlation with sonomicrometry for the assessment of radial strain independently of the heart rate and strain magnitude in a physiological range of values. Though speckle tracking seems to be a reliable and reproducible technique to assess myocardial deformation variations during stress echocardiography, further studies are mandated to analyze the impact of angulated and artefactual out-of-plane motions and inter-vendor variability.

Stressing the Cardiopulmonary Vascular System: The Role of Echocardiography

The cardiopulmonary vascular system represents a key determinant of prognosis in several cardiorespiratory diseases. Although right heart catheterization is considered the gold standard for assessing pulmonary hemodynamics, a comprehensive noninvasive evaluation including left and right ventricular reserve and function and cardiopulmonary interactions remains highly attractive. Stress echocardiography is crucial in the evaluation of many cardiac conditions, typically coronary artery disease but also heart failure and valvular heart disease. In stress echocardiographic applications beyond coronary artery disease, the assessment of the cardiopulmonary vascular system is a cornerstone. The possibility of coupling the left and right ventricles with the pulmonary circuit during stress can provide significant insight into cardiopulmonary physiology in healthy and diseased subjects, can support the diagnosis of the etiology of pulmonary hypertension and other conditions, and can offer valuable prognostic information. In this state-of-the-art document, the topic of stress echocardiography applied to the cardiopulmonary vascular system is thoroughly addressed, from pathophysiology to different stress modalities and echocardiographic parameters, from clinical applications to limitations and future directions.

Reference Values for Physical Stress Echocardiography in Asymptomatic Patients after Mitral Valve Repair

Background

Clinical decision-making in symptomatic patients after mitral valve (MV) repair remains challenging as echocardiographic reference values are lacking. In native MV disease intervention is recommended for mean transmitral pressure gradient (TPG) >15 mmHg or systolic pulmonary artery pressure (SPAP) >60 mmHg at peak exercise. Insight into standard stress echo parameters after MV repair may therefore aid to clinical decision-making during follow-up.

Hypothesis

Stress echocardiography derived parameters in asymptomatic patients after successful MV repair differ from current guidelines for native valves.

Material and methods

In 25 patients (NYHA I) after MV repair stress echocardiography was performed on a semi-supine bicycle. Doppler flow records and MV related hemodynamics at rest and peak were obtained. Linear regression analysis was performed for mean TPG and SPAP at peak, using predetermined variables and confounders.

Results

Mean TPG at rest (3.2 ± 1.4 mmHg) significantly increased at peak (15.0 ± 3.4 mmHg) but was always <25 mmHg. Mean SPAP at rest (21.4 ± 3.8 mmHg) significantly increased at peak (41.8 ± 8.9 mmHg) but was never >57 mmHg. Only the indexed MV ring diameter was inversely correlated to mean TPG at peak in a multivariable model.

Conclusion

In contrast to current recommendations in native MV disease, our data indicate that the standard value for mean TPG during stress echocardiography in asymptomatic patients after successful MV repair was above the guideline threshold of 15 mmHg in >50%, but always <25 mmHg. For SPAP, patients never reached the guideline cutoff (60 mmHg). Long-term follow-up data are needed to provide insight in clinical consequences. Baseline stress echocardiography may indicate individual reference values to compare with during follow-up.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT02371863?term=chamuleau+AND+Mitral&rank=1.