Closing the Last Mile Gap in Access to Multimodality Imaging in Rural Settings: Design of the Imaging Core of the Risk Underlying Rural Areas Longitudinal Study.

Achieving optimal cardiovascular health in rural populations can be challenging for several reasons including decreased access to care with limited availability of imaging modalities, specialist physicians, and other important health care team members. Therefore, innovative solutions are needed to optimize health care and address cardiovascular health disparities in rural areas. Mobile examination units can bring imaging technology to underserved or remote communities with limited access to health care services. Mobile examination units can be equipped with a wide array of assessment tools and multiple imaging modalities such as computed tomography scanning and echocardiography. The detailed structural assessment of cardiovascular and lung pathology, as well as the detection of extracardiac pathology afforded by computed tomography imaging combined with the functional and hemodynamic assessments acquired by echocardiography, yield deep phenotyping of heart and lung disease for populations historically underrepresented in epidemiological studies. Moreover, by bringing the mobile examination unit to local communities, innovative approaches are now possible including engagement with local professionals to perform these imaging assessments, thereby augmenting local expertise and experience. However, several challenges exist before mobile examination unit-based examinations can be effectively integrated into the rural health care setting including standardizing acquisition protocols, maintaining consistent image quality, and addressing ethical and privacy considerations. Herein, we discuss the potential importance of cardiac multimodality imaging to improve cardiovascular health in rural regions, outline the emerging experience in this field, highlight important current challenges, and offer solutions based on our experience in the RURAL (Risk Underlying Rural Areas Longitudinal) cohort study.

Percutaneous MitraClip Device or Surgical Mitral Valve Repair in Patients With Primary Mitral Regurgitation Who Are Candidates for Surgery: Design and Rationale of the REPAIR MR Trial.

Background The current standard of care for the treatment of patients with primary mitral regurgitation (MR) is surgical mitral valve repair. Transcatheter edge-to-edge repair with the MitraClip device provides a less invasive treatment option for patients with both primary and secondary MR. Worldwide, >150 000 patients have been treated with the MitraClip device. However, in the United States, MitraClip is approved for use only in primary patients with MR who are at high or prohibitive risk for mitral valve surgery. The REPAIR MR (Percutaneous MitraClip Device or Surgical Mitral Valve Repair in Patients With Primary Mitral Regurgitation Who Are Candidates for Surgery) trial is designed to compare early and late outcomes associated with transcatheter edge-to-edge repair with the MitraClip and surgical repair of primary MR in older or moderate surgical risk patients. Methods and Results The REPAIR MR trial is a prospective, randomized, parallel-controlled, open-label multicenter, noninferiority trial for the treatment of severe primary MR (verified by an independent echocardiographic core laboratory). Patients with severe MR and indications for surgery because of symptoms (New York Heart Association class II-IV), or without symptoms with left ventricular ejection fraction ≤60%, pulmonary artery systolic pressure >50 mm Hg, or left ventricular end-systolic diameter ≥40 mm are eligible for the trial provided they meet the moderate surgical risk criteria as follows: (1) ≥75 years of age, or (2) if <75 years of age, then the subject has a Society of Thoracic Surgeons Predicted Risk Of Mortality score of ≥2% for mitral repair (or Society of Thoracic Surgeons replacement score of ≥4%), or the presence of a comorbidity that may introduce a surgery-specific risk. The local surgeon must determine that the mitral valve can be surgically repaired. Additionally, an independent eligibility committee will confirm that the MR can be reduced to mild or less with both the MitraClip and surgical mitral valve repair with a high degree of certainty. A total of 500 eligible subjects will be randomized in a 1:1 ratio to receive the MitraClip device or to undergo surgical mitral valve repair (control group). There are 2 co-primary end points for the trial, both of which will be evaluated at 2 years. Each subject will be followed for 10 years after enrollment. The study has received approval from both the Food and Drug Administration and the Centers for Medicare and Medicaid Services, and enrolled its first subject in July 2020. Conclusions The REPAIR MR trial will determine the safety and effectiveness of transcatheter edge-to-edge repair with the MitraClip in patients with primary MR who are at moderate surgical risk and are candidates for surgical MV repair. The trial will generate contemporary comparative clinical evidence for the MitraClip device and surgical MV repair. Registration https://clinicaltrials.gov/ct2/show/NCT04198870; NCT04198870.

Two wrongs sometimes do make a right: errors in aortic valve stenosis assessment by same-day Doppler echocardiography and 4D flow MRI.

This study aims to systematically verify if the simplified geometry and flow profile of the left ventricular outflow tract (LVOT) assumed in 2D echocardiography is appropriate while examining the utility of 4D flow MRI to assess valvular disease. This prospective study obtained same-day Doppler echocardiography and 4D flow MRI in 37 healthy volunteers (age: 51.9 ± 18.2, 20 females) and 7 aortic stenosis (AS) patients (age: 64.2 ± 9.6, 1 female). Two critical assumptions made in echocardiography for aortic valve area assessment were examined, i.e. the assumption of (1) a circular LVOT shape and (2) a flat velocity profile through the LVOT. 3D velocity and shape information obtained with 4D flow MRI was used as comparison. It was found that the LVOT area was lower (by 26.5% and 24.5%) and the velocity time integral (VTI) was higher (by 28.5% and 30.2%) with echo in the healthy and AS group, respectively. These competing errors largely cancelled out when examining individual and cohort averaged LVOT stroke volume. The LVOT area, VTI and stroke volume measured by echo and 4D flow MRI were 3.6 ± 0.7 vs. 4.9 ± 1.0 cm2 (p < 0.001), 21.2 ± 3.0 vs 15.2 ± 2.8 cm (p < 0.001), and 75.6 ± 15.6 vs 72.8 ± 14.1 ml (p = 0.3376), respectively. In the ensemble average of LVOT area and VTI, under- and over-estimation seem to compensate each other to result in a 'realistic' stroke volume. However, it is important to understand that this compensation may fail. 4D flow MRI provides a unique insight into this phenomenon.

Valvular regurgitation flow jet assessment using in vitro 4D flow MRI: Implication for mitral regurgitation.

PURPOSE: The purpose of this study was to evaluate the accuracy of four-dimensional (4D) flow MRI for direct assessment of peak velocity, flow volume, and momentum of a mitral regurgitation (MR) flow jets using an in vitro pulsatile jet flow phantom. We systematically investigated the impact of spatial resolution and quantification location along the jet on flow quantities with Doppler ultrasound as a reference for peak velocity. METHODS: Four-dimensional flow MRI data of a pulsatile jet through a circular, elliptical, and 3D-printed patient-specific MR orifice model was acquired with varying spatial resolution (1.5-5 mm isotropic voxel). Flow rate and momentum of the jet were quantified at various axial distances (x = 0-50 mm) and integrated over time to calculate Voljet and MTIjet . In vivo assessment of Voljet and MTIjet was performed on 3 MR patients. RESULTS: Peak velocities were comparable to Doppler ultrasound (3% error, 1.5 mm voxel), but underestimated with decreasing spatial resolution (-40% error, 5 mm voxel). Voljet was similar to regurgitant volume (RVol) within 5 mm, and then increased linearly with the axial distance (19%/cm) because of flow entrainment. MTIjet remained steady throughout the jet (2%/cm) as theoretically predicted. Four and 9 voxels across the jet were required to measure flow volume and momentum-time-integral within 10% error, respectively. CONCLUSION: Four-dimensional flow MRI detected accurate peak velocity, flow rate, and momentum for in vitro MR-mimicking flow jets. Spatial resolution significantly impacted flow quantitation, which otherwise followed predictions of flow entrainment and momentum conservation. This study provides important preliminary information for accurate in vivo MR assessment using 4D flow MRI.

Imaging Assessment of Tricuspid Regurgitation Severity.

Assessing the severity of tricuspid regurgitation remains a challenging task, and although echocardiography is the test of choice, significant limitations of the current recommendations exist. Newer methods have been used in current trials of transcatheter devices and may improve our understanding of the disease process. Cardiac magnetic resonance imaging and computed tomography angiography may play significant roles as adjunctive imaging modalities. This paper reviews the imaging modalities currently used to quantify tricuspid regurgitation severity.

Myocardial Strain in the Assessment of Patients With Heart Failure: A Review.

Importance: The cornerstones of imaging in heart failure (HF) are the measurement of systolic and diastolic function and left ventricular (LV) filling pressure. Observations: Ejection fraction and the assessment of LV filling pressure and diastolic dysfunction using the ratio of early transmitral flow and LV relaxation (E/e') are conventional imaging markers of LV function. Despite their extensive use in HF guidelines, both have significant detractions, especially in an era when HF with preserved ejection fraction is becoming the dominant presentation. In contrast, strain imaging has provided a new window into myocardial mechanics. Myocardial strain is now well validated, robust, and can easily be performed on most modern echocardiography machines. This Review summarizes the evidence in 9 situations across the stages of HF where LV global longitudinal strain and other strain parameters may provide information on risk prediction, diagnosis, assessment of treatment response, and follow-up. Conclusions and Relevance: The evolution of myocardial deformation imaging from research tool to clinical practice will provide clinicians with a useful additional imaging parameter to facilitate the assessment and risk evaluation of patients with HF.

A Prospective Pilot Study of Pocket-Carried Ultrasound Pre- and Postdischarge Inferior Vena Cava Assessment for Prediction of Heart Failure Rehospitalization.

BACKGROUND: Rehospitalization for heart failure (HF) is common, and subclinical congestion may be present at discharge. Larger inferior vena cava (IVC) size and lower collapsibility at discharge assessed via bedside ultrasound are predictive of rehospitalization; however, the utility of IVC assessment with the use of pocket-carried ultrasound (PCUS) during the transition from discharge to the posthospitalization follow-up visit (FU) has not been investigated. METHODS AND RESULTS: IVCmax and IVCmin were measured with the use of PCUS, and the collapsibility index (IVCCI = [IVCmax - IVCmin]/IVCmax) was determined. The primary outcome was 90-day rehospitalization or death. We prospectively enrolled 49 adults (71 ± 13 years of age, 51% male, 47% black, 43% preserved ejection fraction) hospitalized for HF. Nineteen patients (39%) experienced the outcome. Within the rehospitalized group, discharge and FU mean IVCmax were both >2.1 cm (2.2 ± 0.5 and 2.2 ± 0.7) and IVCCIs <50% (44 ± 20% and 45 ± 24%). Within those not rehospitalized, FU IVCmax was ≤2.1 cm (2.1 ± 0.6 and 1.9 ± 0.6; P = .038) and IVCCI >50% at both time points (55 ± 25% and 62 ± 19%; P = NS). FU IVCCI below an optimal cutoff of 42% had modest discrimination alone (c-statistic = 0.73). FU IVCCI <42% was associated with a greater hazard of the outcome independent of admission log B-type natriuretic peptide (adjusted hazard ratio = 6.8; 95% confidence interval 2.4-19.0; P < .001). CONCLUSIONS: Posthospitalization IVCCI assessment with PCUS predicts HF rehospitalization and may identify patients in need of intervention.

Erratum: Relationship between Right Ventricular Longitudinal Strain, Invasive Hemodynamics, and Functional Assessment in Pulmonary Arterial Hypertension.

[This corrects the article on p. 398 in vol. 45, PMID: 26413108.].

Relationship between Right Ventricular Longitudinal Strain, Invasive Hemodynamics, and Functional Assessment in Pulmonary Arterial Hypertension.

BACKGROUND AND OBJECTIVES: Right ventricular longitudinal strain (RVLS) is a new parameter of RV function. We evaluated the relationship of RVLS by speckle-tracking echocardiography with functional and invasive parameters in pulmonary arterial hypertension (PAH) patients. SUBJECTS AND METHODS: Thirty four patients with World Health Organization group 1 PAH (29 females, mean age 45±13 years old). RVLS were analyzed with velocity vector imaging. RESULTS: Patients with advanced symptoms {New York Heart Association (NYHA) functional class III/IV} had impaired RVLS in global RV (RVLSglobal, -17±5 vs. -12±3%, p<0.01) and RV free wall (RVLSFW, -19±5 vs. -14±4%, p<0.01 to NYHA class I/II). Baseline RVLSglobal and RVLSFW showed significant correlation with 6-minute walking distance (r=-0.54 and r=-0.57, p<0.01 respectively) and logarithmic transformation of brain natriuretic peptide concentration (r=0.65 and r=0.65, p<0.01, respectively). These revealed significant correlations with cardiac index (r=-0.50 and r=-0.47, p<0.01, respectively) and pulmonary vascular resistance (PVR, r=0.45 and r=0.45, p=0.01, respectively). During a median follow-up of 33 months, 25 patients (74%) had follow-up examinations. Mean pulmonary arterial pressure (mPAP, 54±13 to 46±16 mmHg, p=0.03) and PVR (11±5 to 6±2 wood units, p<0.01) were significantly decreased with pulmonary vasodilator treatment. RVLSglobal (-12±5 to -16±5%, p<0.01) and RVLSFW (-14±5 to -18±5%, p<0.01) were significantly improved. The decrease of mPAP was significantly correlated with improvement of RVLSglobal (r=0.45, p<0.01) and RVLSFW (r=0.43, p<0.01). The PVR change demonstrated significant correlation with improvement of RVLSglobal (r=0.40, p<0.01). CONCLUSION: RVLS correlates with functional and invasive hemodynamic parameters in PAH patients. Decrease of mPAP and PVR as a result of treatment was associated with improvement of RVLS.

Perioperative assessment of myocardial deformation.

Evaluation of left ventricular performance improves risk assessment and guides anesthetic decisions. However, the most common echocardiographic measure of myocardial function, the left ventricular ejection fraction (LVEF), has important limitations. LVEF is limited by subjective interpretation that reduces accuracy and reproducibility, and LVEF assesses global function without characterizing regional myocardial abnormalities. An alternative objective echocardiographic measure of myocardial function is thus needed. Myocardial deformation analysis, which performs quantitative assessment of global and regional myocardial function, may be useful for perioperative care of surgical patients. Myocardial deformation analysis evaluates left ventricular mechanics by quantifying strain and strain rate. Strain describes percent change in myocardial length in the longitudinal (from base to apex) and circumferential (encircling the short-axis of the ventricle) direction and change in thickness in the radial direction. Segmental strain describes regional myocardial function. Strain is a negative number when the ventricle shortens longitudinally or circumferentially and is positive with radial thickening. Reference values for normal longitudinal strain from a recent meta-analysis by using transthoracic echocardiography are (mean ± SD) -19.7% ± 0.4%, while radial and circumferential strain are 47.3% ± 1.9% and -23.3% ± 0.7%, respectively. The speed of myocardial deformation is also important and is characterized by strain rate. Longitudinal systolic strain rate in healthy subjects averages -1.10 ± 0.16 s. Assessment of myocardial deformation requires consideration of both strain (change in deformation), which correlates with LVEF, and strain rate (speed of deformation), which correlates with rate of rise of left ventricular pressure (dP/dt). Myocardial deformation analysis also evaluates ventricular relaxation, twist, and untwist, providing new and noninvasive methods to assess components of myocardial systolic and diastolic function. Myocardial deformation analysis is based on either Doppler or a non-Doppler technique, called speckle-tracking echocardiography. Myocardial deformation analysis provides quantitative measures of global and regional myocardial function for use in the perioperative care of the surgical patient. For example, coronary graft occlusion after coronary artery bypass grafting is detected by an acute reduction in strain in the affected coronary artery territory. In addition, assessment of left ventricular mechanics detects underlying myocardial pathology before abnormalities become apparent on conventional echocardiography. Certainly, patients with aortic regurgitation demonstrate reduced longitudinal strain before reduction in LVEF occurs, which allows detection of subclinical left ventricular dysfunction and predicts increased risk for heart failure and impaired myocardial function after surgical repair. In this review, we describe the principles, techniques, and clinical application of myocardial deformation analysis.

Quantitative assessment of mitral regurgitation: how best to do it.

Decisions regarding surgery for mitral regurgitation (MR) are predicated on the accurate quantification of MR severity. Quantitative parameters, including vena contracta width, regurgitant volume and fraction, and effective regurgitant orifice area have prognostic significance and are recommended to be obtained from patients with more than mild MR. New tools for MR quantification have been provided by 3-dimensional echocardiography, cardiac magnetic resonance, and cardiac computed tomography, but limited guidance on appropriate image acquisition and post-processing techniques has hindered their clinical application and reproducibility. This review describes optimal image acquisition and post-processing methods for quantification of MR.

Two-dimensional longitudinal strain assessment in the presence of myocardial contrast agents is only feasible with speckle-tracking after microbubble destruction.

BACKGROUND: Longitudinal strain (LS) imaging is an important tool for the quantification of left ventricular function and deformation, but its assessment is challenging in the presence of echocardiographic contrast agents (CAs). The aim of this study was to test the hypothesis that destruction of microbubbles using high mechanical index (MI) could allow the measurement of LS. METHODS: LS was measured using speckle strain (speckle-tracking LS [STLS]) and Velocity Vector Imaging (VVI) before and after CA administration in 30 consecutive patients. Low MI was used for left ventricular opacification and three-dimensional high MI for microbubble destruction. Four different settings were tested over 60 sec: (1) baseline LS without contrast, (2) LS after CA administration with low MI (0.3), (3) LS after CA administration with high MI (0.9), and (4) LS after microbubble destruction with high MI and three-dimensional imaging. RESULTS: Baseline feasibility of LS assessment (99.3% and 98.2% with STLS and VVI, respectively) was reduced after CA administration using STLS at low (69%, P < .0001) and high (95.4%, P = .0002) MI as well as with VVI (93.8%, P = .004, and 84.7%, P < .0001, respectively). STLS assessment was feasible with high MI after microbubble destruction (1.7% of uninterpretable segments vs 0.7%, P = .26) but not using VVI (7.2% vs 1.8%, P < .001). Regardless of which microbubbles or image settings were used, VVI was associated with significant variability and overestimation of global LS (for low MI, +4.7%, P < .01; for high MI, +3.3%, P < .001; for high MI after microbubble destruction, +1.3%, P = .04). CONCLUSIONS: LS assessment is most feasible without contrast. If a CA is necessary, the calculation of LS is feasible using the speckle-tracking method, if three-dimensional imaging is used as a tool for microbubble destruction 1 min after CA administration.

Quantitative assessment of mitral regurgitation: validation of new methods.

Accurate assessment of mitral regurgitation (MR) severity is important for clinical decision making, prognostication, and decisions regarding timing of surgical intervention. The most common method for noninvasive assessment of MR has been with 2-dimensional transthoracic echocardiography, which is often used as a qualitative tool. Several newer noninvasive modalities including 3-dimensional echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography have also become available for this purpose; however, their role in routine clinical practice is not clearly defined. In this review, we provide an overview of these newer modalities for quantitative assessment of MR severity.

Impact of progression of diastolic dysfunction on mortality in patients with normal ejection fraction.

BACKGROUND: Diastolic dysfunction is an independent predictor of mortality in patients with normal left ventricular ejection fraction. There are limited data, however, on whether worsening of diastolic function is associated with worse prognosis. METHODS AND RESULTS: We reviewed clinical records and echocardiograms of consecutive patients who had baseline echocardiograms between January 1, 2005, and December 31, 2009, that showed left ventricular ejection fraction ≥55% and who subsequently had a follow-up echocardiogram within 6 to 24 months. Diastolic function was labeled as normal, mild, moderate, or severe dysfunction. All-cause mortality was determined by use of the Social Security Death Index. Kaplan-Meier survival analysis and Cox regression analysis with a proportional hazard model were performed to assess outcomes. A total of 1065 outpatients were identified (mean±SD age, 67.9±13.9 years; 58% male). Baseline diastolic dysfunction was present in 770 patients (72.3%), with mild being the most prevalent. On follow-up testing (mean±SD, 1.1±0.4 years), 783 patients (73%) had stable, 168 (16%) had worsening, and 114 (11%) had improved baseline diastolic function. Eighty-eight patients (8.3%) had a decrease in left ventricular ejection fraction to <55% and were more likely to have advanced diastolic dysfunction (P=0.002). After a mean±SD follow-up (from the second study) of 1.6±0.8 years, 142 patients (13%) died. On multivariate analysis, a decrease in left ventricular ejection fraction to <55% and any worsening of diastolic function were independently associated with increased risk of mortality (hazard ratio, 1.78; 95% confidence interval, 1.10-2.85; P=0.02; and hazard ratio, 1.78; 95% confidence interval, 1.21-2.59; P=0.003, respectively). CONCLUSION: In patients with normal baseline left ventricular ejection fraction, worsening of diastolic function is an independent predictor of mortality.

Process evaluation of a cluster randomised controlled trial of a school-based fruit and vegetable intervention: Project Tomato.

OBJECTIVE: The present analysis evaluates the overall appreciation and implementation of an intervention, Project Tomato, designed to maintain fruit and vegetable intake in children aged 8-9 years. DESIGN: A random sample of fifty-four English primary schools (658 children) were randomised to either the intervention group or the control. The intervention group received a multi-component programme delivered in school by teachers and items sent home for parents/children. Dietary measurements were collected at baseline and follow-up. The intervention participants completed questionnaires on the intervention materials, to identify implementation and appreciation of the intervention, and other environmental mechanisms. SETTING: Fifty-four primary schools were randomly selected, with twenty-seven schools allocated to the intervention group. SUBJECTS: A total of 311 children received the intervention. RESULTS: Implementation of the intervention was low, 21·3 % of school items and 56·0 % of home items were implemented. The intervention materials were well received by teachers, parents and children. Other mechanisms that may affect fruit and vegetable intake were explored. Children who ate their main meal with their parents 3-7 nights/week on average consumed 37·6 (95 % CI 9·8, 65·4) g more fruit and vegetables than children who ate with their parents 0-2 times/week. CONCLUSIONS: Implementation of the trial components was poor. However, the results identified the importance of parental environment and mealtime structure on children's fruit and vegetable intake.

Non-invasive assessment of left ventricular relaxation during atrial fibrillation using mitral flow propagation velocity.

AIMS: To elucidate the usefulness of the early diastolic mitral flow propagation velocity (V(p)) obtained from colour M-mode Doppler for non-invasively assessing left-ventricular (LV) relaxation during atrial fibrillation (AF). METHODS AND RESULTS: Ten healthy adult dogs were studied to correlate V(p) with the invasive minimum value of the first derivative of LV pressure decay (dP/dt(min)) and the time constant of isovolumic LV pressure decay (tau) at baseline, during rapid and slow AF, and during AF after inducing myocardial infarction. There were significant positive and negative curvilinear relationships between V(p) and dP/dt(min) and tau, respectively, during rapid AF. After slowing the ventricular rate, the average value of V(p) increased, while dP/dt(min) increased and tau decreased. After inducing myocardial infarction, the average value of V(p) decreased, while dP/dt(min) decreased and tau increased. CONCLUSION: The non-invasively obtained V(p) evaluates LV relaxation even during AF regardless of ventricular rhythm or the presence of pathological changes.