Diastolic function assessment with four-dimensional flow cardiovascular magnetic resonance using automatic deep learning E/A ratio analysis

BACKGROUND

Diastolic left ventricular (LV) dysfunction is a powerful contributor to the symptoms and prognosis of patients with heart failure. In patients with depressed LV systolic function, the E/A ratio, the ratio between the peak early (E) and the peak late (A) transmitral flow velocity, is the first step to defining the grade of diastolic dysfunction. Doppler echocardiography (echo) is the preferred imaging technique for diastolic function assessment, while cardiovascular magnetic resonance (CMR) is less established as a method. Previous four-dimensional (4D) Flow-based studies have looked at the E/A ratio proximal to the mitral valve, requiring manual interaction. In this study, we compare an automated, deep learning-based and two semi-automated approaches for 4D Flow CMR-based E/A ratio assessment to conventional, gold-standard echo-based methods.

METHODS

Ninety-seven subjects with chronic ischemic heart disease underwent a cardiac echo followed by CMR investigation. 4D Flow-based E/A ratio values were computed using three different approaches; two semi-automated, assessing the E/A ratio by measuring the inflow velocity (MVvel) and the inflow volume (MVflow) at the mitral valve plane, and one fully automated, creating a full LV segmentation using a deep learning-based method with which the E/A ratio could be assessed without constraint to the mitral plane (LVvel).

RESULTS

MVvel, MVflow, and LVvel E/A ratios were strongly associated with echocardiographically derived E/A ratio (R2 = 0.60, 0.58, 0.72). LVvel peak E and A showed moderate association to Echo peak E and A, while MVvel values were weakly associated. MVvel and MVflow EA ratios were very strongly associated with LVvel (R2 = 0.84, 0.86). MVvel peak E was moderately associated with LVvel, while peak A showed a strong association (R2 = 0.26, 0.57).

CONCLUSION

Peak E, peak A, and E/A ratio are integral to the assessment of diastolic dysfunction and may expand the utility of CMR studies in patients with cardiovascular disease. While underestimation of absolute peak E and A velocities was noted, the E/A ratio measured with all three 4D Flow methods was strongly associated with the gold standard Doppler echocardiography. The automatic, deep learning-based method performed best, with the most favorable runtime of ∼40 seconds. As both semi-automatic methods associated very strongly to LVvel, they could be employed as an alternative for estimation of E/A ratio.

Deployment of Point-of-Care Echocardiography to Improve Cardiac Diagnostic Access Among American Indians

BACKGROUND

American Indians face significant barriers to diagnosis and management of cardiovascular disease. We sought to develop a real-world implementation model for improving access to echocardiography within the Indian Health Service, the American Indian Structural Heart Disease Partnership.

METHODS AND RESULTS

The American Indian Structural Heart Disease Partnership was implemented and evaluated via a 4-step process of characterizing the system where it would be instituted, building point-of-care echocardiography capacity, deploying active case finding for structural heart disease, and evaluating the approach from the perspective of the clinician and patient. Data were collected and analyzed using a parallel convergent mixed methods approach. Twelve health care providers successfully completed training in point-of-care echocardiography. While there was perceived usefulness of echocardiography, providers found it difficult to integrate screening point-of-care echocardiography into their workday given competing demands. By the end of 12 months, 6 providers continued to actively utilize point-of-care echocardiography. Patients who participated in the study felt it was an acceptable and effective approach. They also identified access to transportation as a notable challenge to accessing echocardiograms. Over the 12-month period, a total of 639 patients were screened, of which 36 (5.6%) had a new clinically significant abnormal finding.

CONCLUSIONS

The American Indian Structural Heart Disease Partnership model exhibited several promising strategies to improve access to screening echocardiography for American Indian populations. However, competing priorities for Indian Health Service providers' time limited the amount of integration of screening echocardiography into outpatient practice. Future endeavors should explore community-based solutions to develop a more sustainable model with greater impact on case detection, disease management, and improved outcomes.

Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

INTRODUCTION

The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures.

METHODS

In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025.

FINDINGS

Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2-6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5-5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4-10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32-4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23-11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation.

INTERPRETATION

After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Haemodynamic effects of hypertension and type 2 diabetes: Insights from a 4D flow MRI-based personalized cardiovascular mathematical model

Type 2 diabetes (T2D) and hypertension increase the risk of cardiovascular diseases mediated by whole-body changes to metabolism, cardiovascular structure and haemodynamics. The haemodynamic changes related to hypertension and T2D are complex and subject-specific, however, and not fully understood. We aimed to investigate the haemodynamic mechanisms in T2D and hypertension by comparing the haemodynamics between healthy controls and subjects with T2D, hypertension, or both. For all subjects, we combined 4D flow magnetic resonance imaging data, brachial blood pressure and a cardiovascular mathematical model to create a comprehensive subject-specific analysis of central haemodynamics. When comparing the subject-specific haemodynamic parameters between the four groups, the predominant haemodynamic difference is impaired left ventricular relaxation in subjects with both T2D and hypertension compared to subjects with only T2D, only hypertension and controls. The impaired relaxation indicates that, in this cohort, the long-term changes in haemodynamic load of co-existing T2D and hypertension cause diastolic dysfunction demonstrable at rest, whereas either disease on its own does not. However, through subject-specific predictions of impaired relaxation, we show that altered relaxation alone is not enough to explain the subject-specific and group-related differences; instead, a combination of parameters is affected in T2D and hypertension. These results confirm previous studies that reported more adverse effects from the combination of T2D and hypertension compared to either disease on its own. Furthermore, this shows the potential of personalized cardiovascular models in providing haemodynamic mechanistic insights and subject-specific predictions that could aid in the understanding and treatment planning of patients with T2D and hypertension. KEY POINTS: The combination of 4D flow magnetic resonance imaging data and a cardiovascular mathematical model allows for a comprehensive analysis of subject-specific haemodynamic parameters that otherwise cannot be derived non-invasively. Using this combination, we show that diastolic dysfunction in subjects with both type 2 diabetes (T2D) and hypertension is the main group-level difference between controls, subjects with T2D, subjects with hypertension, and subjects with both T2D and hypertension. These results suggest that, in this relatively healthy population, the additional load of both hypertension and T2D affects the haemodynamic function of the left ventricle, whereas each disease on its own is not enough to cause significant effects under resting conditions. Finally, using the subject-specific model, we show that the haemodynamic effects of diastolic dysfunction alone are not sufficient to explain all the observed haemodynamic differences. Instead, additional subject-specific variations in cardiac and vascular function combine to explain the complex haemodynamics of subjects affected by hypertension and/or T2D.

4D Flow cardiovascular magnetic resonance consensus statement: 2023 update

Hemodynamic assessment is an integral part of the diagnosis and management of cardiovascular disease. Four-dimensional cardiovascular magnetic resonance flow imaging (4D Flow CMR) allows comprehensive and accurate assessment of flow in a single acquisition. This consensus paper is an update from the 2015 '4D Flow CMR Consensus Statement'. We elaborate on 4D Flow CMR sequence options and imaging considerations. The document aims to assist centers starting out with 4D Flow CMR of the heart and great vessels with advice on acquisition parameters, post-processing workflows and integration into clinical practice. Furthermore, we define minimum quality assurance and validation standards for clinical centers. We also address the challenges faced in quality assurance and validation in the research setting. We also include a checklist for recommended publication standards, specifically for 4D Flow CMR. Finally, we discuss the current limitations and the future of 4D Flow CMR. This updated consensus paper will further facilitate widespread adoption of 4D Flow CMR in the clinical workflow across the globe and aid consistently high-quality publication standards.

Direct current cardioversion in pregnancy: a multicentre study

OBJECTIVE

Direct current cardioversion (DCCV) in pregnancy is rarely required and typically only documented in single case reports or case series. A recent UK confidential enquiry reported on several maternal deaths where appropriate DCCV appeared to have been withheld.

DESIGN

Retrospective cohort study.

SETTING

Seventeen UK and Ireland specialist maternity centres.

SAMPLE

Twenty-seven pregnant women requiring DCCV in pregnancy.

MAIN OUTCOME MEASURES

Maternal and fetal outcomes following DCCV.

RESULTS

Twenty-seven women had a total of 29 DCCVs in pregnancy. Of these, 19 (70%) initial presentations were to Emergency Departments and eight (30%) to maternity settings. There were no maternal deaths. Seventeen of the women (63%) had a prior history of heart disease. Median gestation at DCCV was 28 weeks, median gestation at delivery was 35 weeks, with a live birth in all cases. The abnormal heart rhythms documented at the first cardioversion were atrial fibrillation in 12/27 (44%) cases, atrial flutter in 8/27 (30%), supraventricular tachycardia in 5/27 (19%) and atrial tachycardia in 2/27 (7%). Fetal monitoring was undertaken following DCCV on 14/29 (48%) occasions (10 of 19 (53%) at ≥26 weeks) and on 2/29 (7%) occasions, urgent delivery was required post DCCV.

CONCLUSIONS

Direct current cardioversion in pregnancy is rarely required but should be undertaken when clinically indicated according to standard algorithms to optimise maternal wellbeing. Once the woman is stable post DCCV, gestation-relevant fetal monitoring should be undertaken. Maternity units should develop multidisciplinary processes to ensure pregnant women receive the same standard of care as their non-pregnant counterparts.

Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Impact of prosthetic mitral valve orientation on the ventricular flow field: Comparison using patient-specific computational fluid dynamics

Significant mitral valve regurgitation creates progressive adverse remodeling of the left ventricle (LV). Replacement of the failing valve with a prosthesis generally improves patient outcomes but leaves the patient with non-physiological intracardiac flow patterns that might contribute to their future risk of thrombus formation and embolism. It has been suggested that the angular orientation of the implanted valve might modify the postoperative distortion of the intraventricular flow field. In this study, we investigated the effect of prosthetic valve orientation on LV flow patterns by using heart geometry from a patient with LV dysfunction and a competent native mitral valve to calculate intracardiac flow fields with computational fluid dynamics (CFD). Results were validated using in vivo 4D Flow MRI. The computed flow fields were compared to calculations following virtual implantation of a mechanical heart valve oriented in four different angles to assess the effect of leaflet position. Flow patterns were visualized in long- and short-axes and quantified with flow component analysis. In comparison to a native valve, valve implantation increased the proportion of the mitral inflow remaining in the basal region and further increased the residual volume in the apical area. Only slight changes due to valve orientation were observed. Using our numerical framework, we demonstrated quantitative changes in left ventricular blood flow due to prosthetic mitral replacement. This framework may be used to improve design of prosthetic heart valves and implantation procedures to minimize the potential for apical flow stasis, and potentially assist personalized treatment planning.

Extending Cardiac Functional Assessment with Respiratory-Resolved 3D Cine MRI

This study aimed to develop a cardiorespiratory-resolved 3D magnetic resonance imaging (5D MRI: x-y-z-cardiac-respiratory) approach based on 3D motion tracking for investigating the influence of respiration on cardiac ventricular function. A highly-accelerated 2.5-minute sparse MR protocol was developed for a continuous acquisition of cardiac images through multiple cardiac and respiratory cycles. The heart displacement along respiration was extracted using a 3D image deformation algorithm, and this information was used to cluster the acquired data into multiple respiratory phases. The proposed approach was tested in 15 healthy volunteers (7 females). Cardiac function parameters, including the end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF), were measured for the left and right ventricle in both end-expiration and end-inspiration. Although with the proposed 5D cardiac MRI, there were no significant differences (p > 0.05, t-test) between end-expiration and end-inspiration measurements of the cardiac function in volunteers, incremental respiratory motion parameters that were derived from 3D motion tracking, such as the depth, expiration and inspiration distribution, correlated (p < 0.05, correlation coefficient, Mann-Whitney) with those volume-based parameters of cardiac function and varied between genders. The obtained initial results suggested that this new approach allows evaluation of cardiac function during specific respiratory phases. Thus, it can enable investigation of effects related to respiratory variability and better assessment of cardiac function for studying respiratory and/or cardiac dysfunction.

Post-cardioversion Improvement in LV Function Defined by 4D Flow Patterns and Energetics in Patients With Atrial Fibrillation

Background

Atrial fibrillation (AF) is a prevalent cause of cardiovascular morbidity, including thromboembolism and heart failure. Left ventricular dysfunction (LVD) detected in AF patients may be either precursor or consequence of the arrythmia. Successful cardioversion of chronic AF is often followed by a transient period of left atrial (LA) stunning, where depressed mechanical atrial contraction persists despite reinstitution of sinus rhythm. To determine if AF-associated LVD would improve with resolution of LA dysfunction, AF patients were examined immediately and 4 weeks after cardioversion to sinus rhythm. 4D flow cardiovascular magnetic resonance (CMR) assesses ventricular function according to the volumes and energetics of functional components of the LV volume. Previously, described 4D CMR markers of LVD include decreased volume and end-diastolic kinetic energy (KE) of the Direct flow, which is the portion of LV volume that passes directly from inflow to outflow in a single cycle. We hypothesize that impaired LV flow patterns and energetics will be found immediately after cardioversion during atrial stunning, and that those parameters will improve as atrial function returns.

Methods

Ten patients with a history of AF underwent CMR 2-3 h (Time-1) and 4 weeks (Time-2), following electrical cardioversion to sinus rhythm. 4D phase-contrast velocity data and morphological images were acquired at a 3T CMR system. Using a previously evaluated method, pathlines were emitted from the LV end diastolic volume (LVEDV) and traced forward and backward in time until end-systole. The LVEDV was automatically separated into four functional flow components whose volume and KE were calculated.

Results

Left atrial fractional area change increased over the follow-up period (P = 0.001), indicating recovery of LA mechanical function. LVEF increased between Time-1 and Time-2 (P = 0.003); LVEDVI did not change (P = 0.319). Over that interval, the ratios of Direct flow/LVEDV volume and KE increased (P = 0.001 and P = 0.003, respectively), while the ratios of Residual volume/LVEDV volume and KE decreased (P = 0.001 and P = 0.005, respectively).

Conclusion

Post-cardioversion recovery of LA function was associated with improvements in conventional and 4D CMR markers of LV function. Flow-specific measures demonstrate the negative but potentially reversible impact of LA dysfunction on volume and energetic aspects of LV function.

Maternal and fetal outcomes in pregnancies complicated by the inherited aortopathy Loeys-Dietz syndrome

OBJECTIVE

Pregnancies in women with Loeys-Dietz syndrome (LDS) are rare and are typically documented in case reports only. Early reports suggested high rates of maternal complications during pregnancy and the puerperium, including aortic dissection and uterine rupture, but information on fetal outcomes was very limited.

DESIGN

A retrospective cohort study.

SETTING

Eight specialist UK centres.

SAMPLE

Pregnant women with LDS.

METHODS

Data was collated on cardiac, obstetric, and neonatal outcomes.

MAIN OUTCOME MEASURES

Maternal and perinatal outcomes in pregnancies complicated by LDS.

RESULTS

Twenty pregnancies in 13 women with LDS were identified. There was one miscarriage, one termination of pregnancy, and 18 livebirths. In eight women the diagnosis was known prior to pregnancy but only one woman had preconception counselling. In four women the diagnosis was made during pregnancy through positive genotyping, and the other was diagnosed following delivery. Five women had a family history of aortic dissection. There were no aortic dissections in our cohort during pregnancy or postpartum. Obstetric complications were common, including postpartum haemorrhage (33%) and preterm delivery (50%). In all, 14/18 (78%) of deliveries were by elective caesarean section, at a median gestational age at delivery of 37 weeks. Over half the infants (56%) were admitted to the neonatal unit following delivery.

CONCLUSION

Women with LDS require multidisciplinary specialist management throughout pregnancy. Women should be referred for preconception counselling to make informed decisions around pregnancy risk and outcomes. Early elective preterm delivery needs to be balanced against a high infant admission rate to the neonatal unit.

TWEETABLE ABSTRACT

Pregnancy outcomes in women with Loeys-Dietz syndrome.

Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group

BACKGROUND

The purpose of this statement is to update the recommendations by the American Heart Association (AHA) for the prevention of infective endocarditis, which were last published in 1997.

METHODS AND RESULTS

A writing group appointed by the AHA for their expertise in prevention and treatment of infective endocarditis (IE) with liaison members representing the American Dental Association, the Infectious Diseases Society of America and the American Academy of Pediatrics. The writing group reviewed input from national and international experts on IE. The recommendations in this document reflect analyses of relevant literature regarding procedure-related bacteremia and IE; in vitro susceptibility data of the most common microorganisms, which cause IE; results of prophylactic studies in animal models of experimental endocarditis; and retrospective and prospective studies of prevention of IE. MEDLINE database searches from 1950 through 2006 were done for English language articles using the following search terms: endocarditis, infective endocarditis, prophylaxis, prevention, antibiotic, antimicrobial, pathogens, organisms, dental, gastrointestinal, genitourinary, streptococcus, enterococcus, staphylococcus, respiratory, dental surgery, pathogenesis, vaccine, immunization and bacteremia. The reference lists of the identified articles were also searched. The writing group also searched the AHA online library. The American College of Cardiology/AHA classification of recommendations and levels of evidence for practice guidelines were used. The article subsequently was reviewed by outside experts not affiliated with the writing group and by the AHA Science Advisory and Coordinating Committee.

CONCLUSIONS

The major changes in the updated recommendations include the following. (1) The committee concluded that only an extremely small number of cases of IE might be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100 percent effective. (2) IE prophylaxis for dental procedures should be recommended only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from IE. (3) For patients with these underlying cardiac conditions, prophylaxis is recommended for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. (4) Prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of IE. (5) Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure. These changes are intended to define more clearly when IE prophylaxis is or is not recommended and to provide more uniform and consistent global recommendations.

Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group

BACKGROUND

The purpose of this statement is to update the recommendations by the American Heart Association (AHA) for the prevention of infective endocarditis that were last published in 1997.

METHODS AND RESULTS

A writing group was appointed by the AHA for their expertise in prevention and treatment of infective endocarditis, with liaison members representing the American Dental Association, the Infectious Diseases Society of America, and the American Academy of Pediatrics. The writing group reviewed input from national and international experts on infective endocarditis. The recommendations in this document reflect analyses of relevant literature regarding procedure-related bacteremia and infective endocarditis, in vitro susceptibility data of the most common microorganisms that cause infective endocarditis, results of prophylactic studies in animal models of experimental endocarditis, and retrospective and prospective studies of prevention of infective endocarditis. MEDLINE database searches from 1950 to 2006 were done for English-language papers using the following search terms: endocarditis, infective endocarditis, prophylaxis, prevention, antibiotic, antimicrobial, pathogens, organisms, dental, gastrointestinal, genitourinary, streptococcus, enterococcus, staphylococcus, respiratory, dental surgery, pathogenesis, vaccine, immunization, and bacteremia. The reference lists of the identified papers were also searched. We also searched the AHA online library. The American College of Cardiology/AHA classification of recommendations and levels of evidence for practice guidelines were used. The paper was subsequently reviewed by outside experts not affiliated with the writing group and by the AHA Science Advisory and Coordinating Committee.

CONCLUSIONS

The major changes in the updated recommendations include the following: (1) The Committee concluded that only an extremely small number of cases of infective endocarditis might be prevented by antibiotic prophylaxis for dental procedures even if such prophylactic therapy were 100% effective. (2) Infective endocarditis prophylaxis for dental procedures is reasonable only for patients with underlying cardiac conditions associated with the highest risk of adverse outcome from infective endocarditis. (3) For patients with these underlying cardiac conditions, prophylaxis is reasonable for all dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. (4) Prophylaxis is not recommended based solely on an increased lifetime risk of acquisition of infective endocarditis. (5) Administration of antibiotics solely to prevent endocarditis is not recommended for patients who undergo a genitourinary or gastrointestinal tract procedure. These changes are intended to define more clearly when infective endocarditis prophylaxis is or is not recommended and to provide more uniform and consistent global recommendations.

Effect of heel elevation on forelimb conformation in horses

OBJECTIVE

To determine the conformational changes in the distal forelimb of horses following heel elevation of 15 degrees and greater. An experimental study with repeated, within-horse measurements.

PROCEDURE

Five clinically normal, mixed-breed horses were used to determine distal forelimb conformation following heel elevation from 0 to 45 degrees in 15 degree increments. Data were also compared to conformation of the limb in a Kimzey splint. Conformation was determined using lateral to medial radiographic projections. Conformation parameters assessed included measurement of apparent lengths of digital flexor tendons from the origin of their accessory ligaments to the points of insertion, and the joint angles of the distal limb.

RESULTS

For angles of heel elevation from 15 to 45 degrees, the degree of joint angulation increased (increasing flexion) with heel elevation for the metacarpophalangeal, and proximal and distal interphalangeal joints. Conversely, the measured apparent lengths of the digital flexor tendons in the distal limb, decreased.

CONCLUSION

The data supports the practice of elevating the heel (greater than 15 degrees) for conditions in which decreased fetlock extension may be desired such as with laceration or injury to the digital flexor tendons. Further study is required to determine whether heel elevation greater than 15 degrees reduces in vivo digital flexor tendon tension and also to ensure that the marked flexion of the distal interphalangeal joint with greater heel elevation is not detrimental over a prolonged period that may be required for the rehabilitation of flexor tendon injuries in the horse.

Characterization of an acute inpatient hospice palliative care unit in a U.S. teaching hospital

An existing hospice palliative care inpatient unit was studied from September 1993 to November 1993 to characterize it for two qualities: demographics of admitted patients and family satisfaction after discharge. The purpose of this study was to identify current uses of the unit and determine whether the high level of satisfaction among family members, as perceived by the staff, was accurate. To characterize demographics, 100 consecutive admissions to the unit were assessed prospectively beginning in September 1993. To characterize family satisfaction, a survey was sent to the families of 240 patients who had been cared for on the inpatient unit. Since this study, it has been identified that care on the hospice palliative care unit is provided at a 50% reduction in daily hospital charges. The hospital has benefited from establishing and maintaining an acute care inpatient hospice palliative care unit. Other academic medical centers in the United States should consider a designated unit for symptom management and terminal care as part of their comprehensive range of healthcare services.

Incidence of transcranial Doppler-detected cerebral microemboli in patients referred for echocardiography

BACKGROUND AND PURPOSE

Transcranial Doppler can detect cerebral microemboli. These emboli may be a risk factor for embolic stroke. We studied the prevalence of microemboli in patients referred for echocardiography.

METHODS

Forty-two patients were evaluated. Patients were studied with continuous monitoring over one middle cerebral artery for 30 minutes, and the number of microemboli was recorded. Patients were divided into three groups, those with prosthetic heart valves (group A, n = 15), atrial fibrillation (group B, n = 14), and no major cardiac risk factor (group C, n = 14).

RESULTS

Seventeen percent (7 of 42) of all patients had microemboli. In group A, 5 of 15 (33%) had microemboli. In group B, 2 of 13 (15%) patients had microemboli. Twenty-five percent (7 of 28) of patients in groups A and B combined (A+B) had microemboli. No patients (0 of 14) in group C had microemboli. Groups A and A+B had significantly more emboli than group C (P < .05). Prosthetic heart valve patients with emboli more commonly had a history of prior stroke than valve patients without emboli (3 of 5 versus 2 of 10). The number of emboli seen per 30-minute monitoring session was greater in patients with a prior history of stroke than in patients without (10 microemboli versus 3).

CONCLUSIONS

Microemboli can be found in a significant percentage of selected patients referred for echocardiography. The prevalence of microembolism is greater in patients with a known high risk of embolization (eg, prosthetic valves) and less in patients with a lower risk of embolization (eg, atrial fibrillation). These microemboli may be associated with an increased prevalence of previous stroke in patients with prosthetic valves.

Transesophageal echocardiographic findings in stroke subtypes

BACKGROUND AND PURPOSE

Transesophageal echocardiography has a high yield for detecting potential cardiac sources of embolism in patients with clinical risk factors for cardioembolism or unexplained stroke. The yield in other stroke subtypes is unknown.

METHODS

We classified 145 consecutively admitted patients into stroke subtypes based on clinical findings, brain imaging, and carotid ultrasound. Both transesophageal and transthoracic echocardiography were performed to detect left atrial thrombi, spontaneous echo contrast, atrial septal aneurysm, interatrial shunts, ventricular thrombus or aneurysm, and myxomatous mitral valve.

RESULTS

Transesophageal echocardiography documented at least one of these findings in 46% of the patients compared with an 8% yield on the transthoracic study (P = .002). The yield of transesophageal echocardiography was substantial in all stroke subgroups. Patients with clinical risk factors for cardiac embolism had the highest frequency of spontaneous echo contrast (P = .001). Atrial septal aneurysms were most frequent in patients with lacunar syndromes (P = .012), and interatrial shunts were common in all stroke subtypes.

CONCLUSIONS

Transesophageal echocardiographic findings vary considerably between stroke subgroups.

Tricuspid valve repair. Operative and follow-up evaluation by Doppler color flow mapping

Severe tricuspid regurgitation may produce significant morbidity and mortality if not corrected, but commonly used methods of intraoperative assessment may be unreliable. Tricuspid regurgitation was evaluated by a new intraoperative technique, Doppler color flow mapping, in 85 patients before and after cardiopulmonary bypass. Regurgitation grade by intraoperative color Doppler mapping correlated well with right ventricular angiography (kappa value = 0.92, p less than 0.01; n = 8) and with preoperative color Doppler studies (kappa = 0.71, p less than 0.05; n = 51). The right atrial V wave correlated poorly with the severity of tricuspid regurgitation intraoperatively, both before (r = 0.30) and after (r = -0.05, p = no significant difference) cardiopulmonary bypass. Advanced (3+ or 4+) tricuspid regurgitation was found in 40% (21) of 52 patients requiring mitral valve repair or replacement. Tricuspid annuloplasty with a prosthetic ring provided a significant (greater than or equal to 2 grade) reduction in regurgitation severity in 94% (17/18; p less than 0.05). Without repair, tricuspid regurgitation decreased to a similar degree after mitral valve operations in 14% (5/36); only one of the five patients had advanced tricuspid regurgitation prepump. Fluid filling of the arrested right ventricle after the surgical procedure did not predict regurgitation severity (false negative rate 50%, 2/4; false positive rate 22%, 2/9). Regurgitation grade remained unchanged after the initial postpump study, up to 60 weeks postoperatively. In conclusion, color Doppler flow mapping provides more accurate intraoperative assessment of tricuspid regurgitation than the right atrial V wave or fluid filling of the right ventricle. This semiquantitative technique aids in the selection of patients appropriate for surgical repair of the tricuspid valve and is useful in judging the adequacy of tricuspid valve repair before chest closure. Advanced (3+ or 4+) tricuspid regurgitation is a common occurrence in patients undergoing mitral valve repair or replacement and rarely responds to conservative (nonoperative) management. Ring annuloplasty provides a highly effective and durable reduction in tricuspid regurgitation.

Transesophageal two-dimensional echocardiography and color Doppler flow velocity mapping in the evaluation of cardiac valve prostheses

To determine the value of transesophageal ultrasound in the assessment of cardiac valve prostheses, 14 patients with clinically suspected mitral prosthesis malfunction were studied by transthoracic and transesophageal two-dimensional imaging as well as by color Doppler flow velocity mapping (color Doppler). Patients underwent left ventricular angiography (n = 13), surgery (n = 11), or both angiography and surgery (n = 10). Nine patients had only mitral valve replacement, four patients had both mitral and aortic valve replacement, and one patient had mitral, aortic, and tricuspid valve replacement. There were 16 biological and four mechanical prostheses. The degree of mitral regurgitation was graded by both transthoracic and transesophageal color Doppler according to the area of the regurgitant jet visualized and was compared with a three-point classification of mitral regurgitation by left ventricular angiography judged by observers blinded to the echocardiographic results. All transesophageal studies were performed without complication and were well tolerated. The pathological morphology of the mitral prosthesis was additionally or more clearly visualized by transesophageal two-dimensional imaging and subsequently proven at surgery in three patients with flail leaflets and one patient with a vegetation compared with images obtained by the transthoracic approach. Valvular regurgitation was graded by the transthoracic approach as absent in four patients, mild in two patients, moderate in five patients, and severe in only three patients. The transesophageal assessment showed absence of mitral regurgitation in two patients, moderate regurgitation in two patients, and severe regurgitation in 10 patients.(ABSTRACT TRUNCATED AT 250 WORDS)