Artificial intelligence-based classification of echocardiographic views.

Aims: Augmenting echocardiography with artificial intelligence would allow for automated assessment of routine parameters and identification of disease patterns not easily recognized otherwise. View classification is an essential first step before deep learning can be applied to the echocardiogram. Methods and results: We trained two- and three-dimensional convolutional neural networks (CNNs) using transthoracic echocardiographic (TTE) studies obtained from 909 patients to classify nine view categories (10 269 videos). Transthoracic echocardiographic studies from 229 patients were used in internal validation (2582 videos). Convolutional neural networks were tested on 100 patients with comprehensive TTE studies (where the two examples chosen by CNNs as most likely to represent a view were evaluated) and 408 patients with five view categories obtained via point-of-care ultrasound (POCUS). The overall accuracy of the two-dimensional CNN was 96.8%, and the averaged area under the curve (AUC) was 0.997 on the comprehensive TTE testing set; these numbers were 98.4% and 0.998, respectively, on the POCUS set. For the three-dimensional CNN, the accuracy and AUC were 96.3% and 0.998 for full TTE studies and 95.0% and 0.996 on POCUS videos, respectively. The positive predictive value, which defined correctly identified predicted views, was higher with two-dimensional rather than three-dimensional networks, exceeding 93% in apical, short-axis aortic valve, and parasternal long-axis left ventricle views. Conclusion: An automated view classifier utilizing CNNs was able to classify cardiac views obtained using TTE and POCUS with high accuracy. The view classifier will facilitate the application of deep learning to echocardiography.

New Approaches to Assessment and Management of Tricuspid Regurgitation Before Intervention.

Severe tricuspid regurgitation (TR) is a progressive condition associated with substantial morbidity, poor quality of life, and increased mortality. Patients with TR commonly have coexisting conditions including congestive heart failure, pulmonary hypertension, chronic lung disease, atrial fibrillation, and cardiovascular implantable electronic devices, which can increase the complexity of medical and surgical TR management. As such, the optimal timing of referral for isolated tricuspid valve (TV) intervention is undefined, and TV surgery has been associated with elevated risk of morbidity and mortality. More recently, an unprecedented growth in TR treatment options, namely the development of a wide range of transcatheter TV interventions (TTVI) is stimulating increased interest and referral for TV intervention across the entire medical community. However, there are no stepwise algorithms for the optimal management of symptomatic severe TR before TTVI. This article reviews the contemporary assessment and management of TR with addition of a medical framework to optimize TR before referral for TTVI.

Disproportionately High Aortic Valve Calcium Scores in Atrial Fibrillation: Implications for Transcatheter Aortic Valve Replacement.

AIMS: Doppler mean gradient (MG) can underestimate aortic stenosis (AS) severity in patients with atrial fibrillation (AF) compared to patients in sinus rhythm (SR), potentially delaying intervention in AF. This study compared outcomes in patients with AF and SR following transcatheter aortic valve replacement (TAVR) and investigated delay in TAVR based on computed tomography aortic valve calcium score (AVCS). METHODS AND RESULTS: Patients who underwent TAVR from 2013 to 2017 for native valve severe AS were identified from an institutional database. Baseline characteristics and overall survival were compared between those in SR and AF. There were 820 patients (mean age 81 years; 41.6% female) included. AF was present in 356 patients. Patients in AF were older (82.2 vs. 80.5, p = 0.003), had lower MG compared to SR patients (42.0 vs. 44.9, p = 0.002) with similar indexed aortic valve area (0.4 vs. 0.4, p = 0.17). Median AVCS was higher in AF (males: AF 2850.0 vs. SR 2561.0, p = 0.044; females: AF 1942.0 vs. SR 1610.5, p = 0.025). Projected AVCS assuming same age of diagnosis was similar between AF and SR. Median survival post-TAVR was worse in AF compared to SR (3.2 vs 5.4 years, log rank p < 0.001). AF, lower MG, higher RVSP, dialysis, diabetes, and significant TR were associated with higher mortality (p < 0.05 for all). CONCLUSION: Older age and higher AVCS in patients with AF compared to SR suggests that AS was both underestimated and more advanced at TAVR referral.

The Natural History of Atrial Functional Mitral Regurgitation.

BACKGROUND: The natural history of moderate/severe atrial functional mitral regurgitation (AFMR) is unknown. OBJECTIVES: The authors sought to study the incidence of left ventricular (LV) systolic dysfunction (LVSD), progression or regression of ≥mild-moderate AFMR, and impact on mortality. METHODS: Adults with left atrial (LA) volume index ≥40 mL/m2, ≥mild-moderate AFMR, and follow-up echocardiogram were followed for incident LVSD (ejection fraction <50% and ≥10% lower than baseline), progression of mild-moderate/moderate AFMR to severe, and persistent regression of AFMR to no/trivial. Relation of AFMR progression or regression as time-dependent covariates with all-cause mortality was studied. Incidence of LVSD was compared with patients with no/mild AFMR matched on age, sex, comorbidities and ejection fraction. Patients were followed until mitral intervention, myocardial infarction, or last follow-up. RESULTS: A total of 635 patients (median age 75 years, 51% female, 96% mild-moderate/moderate AFMR, 4% severe AFMR) were included. Over a median 2.2 years (Q1-Q3: 1.0-4.3 years), incidence rates per 100 person-years were 3.2 for LVSD (P = 0.52 vs patients with no/mild AFMR), 1.9 for progression of AFMR, and 3.9 for regression. Female sex and larger LA volume index were independently associated with progression, whereas younger age, male sex, absent atrial fibrillation, and higher LA emptying fraction were independently associated with regression. Neither AFMR progression nor regression was independently associated with mortality. Instead, independent risk factors for mortality included older age, concentric LV geometry, and higher estimated LV filling and pulmonary pressures. CONCLUSIONS: In patients with predominantly mild-moderate/moderate AFMR, regression of MR was more common than progression, but neither was associated with mortality. Instead, diastolic function abnormalities were more important. Over a median 2-year follow-up, LVSD risk was not increased.

Pulmonary Vein Flow Morphology After Transcatheter Mitral Valve Edge-to-Edge Repair as Predictor of Survival.

BACKGROUND: Data on the prognostic factors after mitral valve (MV) transcatheter edge-to-edge repair (TEER; MV-TEER) are limited. Pulsed-wave Doppler interrogation of pulmonary vein flow (PVF) is a convenient method to assess the hemodynamic burden of residual mitral regurgitation (MR), which could be of utility as a predictor of outcomes. METHODS: Patients that underwent MV-TEER between May 2014 and December 2021 at our institution were evaluated. Pulmonary vein flow patterns post-MV-TEER were reviewed on the procedural transesophageal echocardiogram and classified as normal (systolic dominant or codominant) or abnormal (systolic blunting or reversal). The PVF pattern was correlated with all-cause mortality at follow-up. RESULTS: Two-hundred sixty-five patients had diagnostic PVF post-MV-TEER, with 73 (27.5%) categorized as normal and 192 (72.5%) categorized as abnormal. Patients with abnormal PVF morphology were more likely to have atrial fibrillation (70% vs 42%, P < .001) and greater than moderate residual MR (16% vs 3%, P = .01) and had higher mean left atrial pressure (18.1 ± 5.0 vs 15.9 ± 4.2 mm Hg, P = .002) and left atrial V wave (26.6 ± 8.5 vs 21.4 ± 7.3 mm Hg, P < .001) postprocedure. In multivariable analysis, abnormal PVF morphology post-MV-TEER was independently associated with mortality at follow-up (hazard ratio = 1.70; 95% CI, 1.06-2.74; P = .03) after correction for end-stage renal disease, atrial fibrillation, and residual MR. Results were similar in subgroups of patients with moderate or less and those with mild or less residual MR. CONCLUSIONS: Pulmonary vein flow morphology is a simple and objective tool to assess MR severity immediately post-MV-TEER and offers important prognostic information to optimize procedural results. Additional studies are needed to determine whether patients with abnormal PVF pattern post-MV-TEER would benefit from more intensive goal-directed medical therapy postprocedure.

Mitral Annulus Calcium Score in Patients With Calcific Mitral Stenosis Undergoing Invasive Hemodynamic Assessment.

BACKGROUND: Aortic valve calcium score is associated with hemodynamic severity of aortic stenosis. Whether this association is present in calcific mitral stenosis remains unknown. METHODS AND RESULTS: This study was a retrospective analysis of consecutive patients with mitral stenosis secondary to mitral annular calcification (MAC) undergoing transseptal catheterization. All patients underwent invasive mitral valve assessment via direct left atrial and left ventricular pressure measurement. Computed tomography within 1 year of cardiac catheterization and with adequate visualization of the mitral annulus was included. MAC calcium score quantification by Agatston method was obtained offline using dedicated software (Aquarius, TeraRecon, V.4). Median patient age was 66.9±11.2 years, 47% of patients were women, 50% had coronary artery disease, 40% had atrial fibrillation, 47% had prior cardiac surgery, and 33% had prior chest radiation. Median diastolic mitral valve gradient was 9.4±3.4 mm Hg on echocardiography and 8.5±4 mm Hg invasively. Invasive median mitral valve area using the Gorlin formula was 1.87±0.9 cm2. Median MAC calcium score for the cohort was 7280±7937 Hounsfield units. MAC calcium score correlated with the presence of atrial fibrillation (P=0.02) but was not associated with other comorbidities. There was no correlation between MAC calcium score and mitral valve area (r=0.07; P=0.6) or mitral valve gradient (r=-0.03; P=0.8). CONCLUSIONS: MAC calcium score did not correlate with invasively measured mitral valve gradient and mitral valve area in patients with MAC-related mitral stenosis, suggesting that calcium score should not be used as a surrogate for invasive hemodynamic parameters.

Biatrial myopathy in heart failure with preserved ejection fraction.

AIM: Left atrial (LA) myopathy is increasingly recognized as an important phenotypic trait in heart failure (HF) with preserved ejection fraction (HFpEF). Right atrial (RA) remodelling and dysfunction also develop in HFpEF, but little data are available regarding the clinical characteristics and pathophysiology among patients with isolated LA, RA, or biatrial myopathy. METHODS AND RESULTS: Patients with HFpEF underwent invasive haemodynamic exercise testing, comprehensive imaging including speckle tracking strain echocardiography, and clinical follow-up at Mayo Clinic between 2006 and 2018. LA myopathy was defined as LA volume index >34 ml/m2 and/or LA reservoir strain ≤24% and RA myopathy by RA volume index >39 ml/m2 in men and >33 ml/m2 in women and/or RA reservoir strain ≤19.8%. Of 476 consecutively evaluated patients with HFpEF defined by invasive exercise testing with evaluable atrial structure/function, 125 (26%) had no atrial myopathy, 147 (31%) had isolated LA myopathy, 184 (39%) had biatrial myopathy, and 20 (4%) had isolated RA myopathy. Patients with HFpEF and biatrial myopathy had more atrial fibrillation, poorer left ventricular systolic and diastolic function, more severe pulmonary vascular disease, tricuspid regurgitation, ventricular interdependence and right ventricular dysfunction, and poorer cardiac output reserve with exercise. There were 94 patients with events over a median follow-up of 2.9 (interquartile range 1.4-4.6) years. Individuals with biatrial myopathy had an 84% higher risk of HF hospitalization or death as compared to those with isolated LA myopathy (hazard ratio 1.84; 95% confidence interval 1.16-2.92, p = 0.01). CONCLUSIONS: Biatrial myopathy identifies patients with more advanced HFpEF characterized by more severe pulmonary vascular disease, right HF, poorer cardiac reserve, and a greater risk for adverse outcomes. Further study is required to define optimal strategies to treat and prevent biatrial myopathy in HFpEF.

Prognostic Significance of Elevated Left Ventricular Filling Pressures with Exercise: Insights from a Cohort of 14,338 Patients.

BACKGROUND: Exercise echocardiography can assess for cardiovascular causes of dyspnea other than coronary artery disease. However, the prevalence and prognostic significance of elevated left ventricular (LV) filling pressures with exercise is understudied. METHODS: We evaluated 14,338 patients referred for maximal symptom-limited treadmill echocardiography. In addition to assessment of LV regional wall motion abnormalities (RWMAs), we measured patients' early diastolic mitral inflow (E), septal mitral annulus relaxation (e'), and peak tricuspid regurgitation velocity before and immediately after exercise. RESULTS: Over a mean follow-up of 3.3 ± 3.4 years, patients with E/e' ≥15 with exercise (n = 1,323; 9.2%) had lower exercise capacity (7.3 ± 2.1 vs 9.1 ± 2.4 metabolic equivalents, P < .0001) and were more likely to have resting or inducible RWMAs (38% vs 18%, P < .0001). Approximately 6% (n = 837) had elevated LV filling pressures without RWMAs. Patients with a poststress E/e' ≥15 had a 2.71-fold increased mortality rate (2.28-3.21, P < .0001) compared with those with poststress E/e' ≤ 8. Those with an E/e' of 9 to 14, while at lower risk than the E/e' ≥15 cohort (hazard ratio [HR] = 0.58 [0.48-0.69]; P < .0001), had higher risk than if E/e' ≤8 (HR = 1.56 [1.37-1.78], P < .0001). On multivariable analysis, adjusting for age, sex, exercise capacity, LV ejection fraction, and presence of pulmonary hypertension with stress, patients with E/e' ≥15 had a 1.39-fold (95% CI, 1.18-1.65, P < .0001) increased risk of all-cause mortality compared with patients without elevated LV filling pressures. Compared with patients with E/e' ≤ 15 after exercise, patients with E/e' ≤15 at rest but elevated after exercise had a higher risk of cardiovascular death (HR = 8.99 [4.7-17.3], P < .0001). CONCLUSION: Patients with elevated LV filling pressures are at increased risk of death, irrespective of myocardial ischemia or LV systolic dysfunction. These findings support the routine incorporation of LV filling pressure assessment, both before and immediately following stress, into the evaluation of patients referred for exercise echocardiography.

Impact on Kidney Function and Medium-Term Outcomes of Transcatheter Aortic Valve Replacement in Patients With Chronic Kidney Disease.

Transcatheter aortic valve replacement (TAVR) is now widely approved for the treatment of aortic stenosis, regardless of the patients' surgical risk. However, the outcomes of TAVR and their determinants in patients with chronic kidney disease (CKD) beyond 1 year of follow-up are unknown. We aimed to assess the medium-term outcomes of TAVR in CKD, develop a risk score to estimate the 2-year mortality in patients with CKD, and evaluate the changes in kidney function at discharge after TAVR. Adults who underwent TAVR were retrospectively identified. The CKD stage was determined using the Chronic Kidney Disease Epidemiology 2021 creatinine formula. Improved kidney function was defined as post-TAVR creatinine ≤50% of pre-TAVR creatinine or decrease in creatinine of ≥0.3 mg/100 ml compared with pre-TAVR creatinine. Overall, 1,523 patients (median age 82 years; 59% men; 735 with CKD stage II or less, 661 with CKD III, 83 with CKD IV, and 44 with CKD V [of whom 40 were on dialysis]) were included. The all-cause mortality was higher in CKD stages IV and V on the multivariable analysis (p <0.001) at median follow-up of 2.9 (interquartile range 2.0 to 4.2) years. Moderate or severe tricuspid regurgitation, anemia, right ventricular systolic pressure >40 mm Hg and CKD stages IV and V were independent predictors of 2-year mortality and were used to develop a risk score. At hospital discharge, persisting acute kidney injury after TAVR occurred in 88 of 1,466 patients (6%), whereas improved kidney function occurred in 170 of 1,466 patients (12%). In conclusion, CKD stage was an independent determinant of mortality beyond 2 years after TAVR. Kidney function was more likely to improve than worsen at the time of hospital discharge after TAVR.

Machine learning facilitates the prediction of long-term mortality in patients with tricuspid regurgitation.

OBJECTIVE: Tricuspid regurgitation (TR) is a prevalent valve disease associated with significant morbidity and mortality. We aimed to apply machine learning (ML) to assess risk stratification in patients with ≥moderate TR. METHODS: Patients with ≥moderate TR on echocardiogram between January 2005 and December 2016 were retrospectively included. We used 70% of data to train ML-based survival models including 27 clinical and echocardiographic features to predict mortality over a 3-year period on an independent test set (30%). To account for differences in baseline comorbidities, prediction was performed in groups stratified by increasing Charlson Comorbidity Index (CCI). Permutation feature importance was calculated using the best-performing model separately in these groups. RESULTS: Of 13 312 patients, mean age 72 ± 13 years and 7406 (55%) women, 7409 (56%) had moderate, 2646 (20%) had moderate-severe and 3257 (24%) had severe TR. The overall performance for 1-year mortality by 3 ML models was good, c-statistic 0.74-0.75. Interestingly, performance varied between CCI groups, (c-statistic = 0.774 in lowest CCI group and 0.661 in highest CCI group). The performance decreased over 3-year follow-up (average c-index 0.78). Furthermore, the top 10 features contributing to these predictions varied slightly with the CCI group, the top features included heart rate, right ventricular systolic pressure, blood pressure, diuretic use and age. CONCLUSIONS: Machine learning of common clinical and echocardiographic features can evaluate mortality risk in patients with TR. Further refinement of models and validation in prospective studies are needed before incorporation into the clinical practice.

Bicuspid aortic valve: long-term morbidity and mortality.

BACKGROUND AND AIMS: Bicuspid aortic valve (BAV) is the most common congenital heart anomaly. Lifetime morbidity and whether long-term survival varies according to BAV patient-sub-groups are unknown. This study aimed to assess lifetime morbidity and long-term survival in BAV patients in the community. METHODS: The authors retrospectively identified all Olmsted County (Minnesota) residents with an echocardiographic diagnosis of BAV from 1 January 1980 to 31 December 2009, including patients with typical valvulo-aortopathy (BAV without accelerated valvulo-aortopathy or associated disorders), and those with complex valvulo-aortopathy (BAV with accelerated valvulo-aortopathy or associated disorders). RESULTS: 652 consecutive diagnosed BAV patients [median (IQR) age 37 (22-53) years; 525 (81%) adult and 127 (19%) paediatric] were followed for a median (IQR) of 19.1 (12.9-25.8) years. The total cumulative lifetime morbidity burden (from birth to age 90) was 86% (95% CI 82.5-89.7); cumulative lifetime progression to ≥ moderate aortic stenosis or regurgitation, aortic valve surgery, aortic aneurysm ≥45 mm or z-score ≥3, aorta surgery, infective endocarditis and aortic dissection was 80.3%, 68.5%, 75.4%, 27%, 6% and 1.6%, respectively. Survival of patients with typical valvulo-aortopathy [562 (86%), age 40 (28-55) years, 86% adults] was similar to age-sex-matched Minnesota population (P = .12). Conversely, survival of patients with complex valvulo-aortopathy [90 (14%), age 14 (3-26) years, 57% paediatric] was lower than expected, with a relative excess mortality risk of 2.25 (95% CI 1.21-4.19) (P = .01). CONCLUSION: The BAV condition exhibits a high lifetime morbidity burden where valvulo-aortopathy is close to unavoidable by age 90. The lifetime incidence of infective endocarditis is higher than that of aortic dissection. The most common BAV clinical presentation is the typical valvulo-aortopathy with preserved expected long-term survival, while the complex valvulo-aortopathy presentation incurs higher mortality.

Incidence, risk factors, and outcomes of atrial functional mitral regurgitation in patients with atrial fibrillation or sinus rhythm.

AIMS: Atrial functional mitral regurgitation (AFMR) has been associated with atrial fibrillation (AF) and heart failure with preserved ejection fraction. However, data on incident AFMR are scarce. We aimed to study the incidence, risk factors, and clinical significance of AFMR in AF or sinus rhythm (SR). METHODS AND RESULTS: Adults with new diagnosis of AF and adults in SR were identified. Patients with >mild MR at baseline, primary mitral disease, cardiomyopathy, left-sided valve disease, previous cardiac surgery, or with no follow-up echocardiogram were excluded. Diastolic dysfunction (DD) was indicated by ≥2/4 abnormal diastolic function parameters [mitral medial e', mitral medial E/e', tricuspid regurgitation velocity, left atrial volume index (LAVI)]. Overall, 1747 patients with AF and 29 623 in SR were included. Incidence rate of >mild AFMR was 2.6 per 100 person-year in new-onset AF and 0.7 per 100 person-year in SR, P < 0.001. AF remained associated with AFMR in a propensity score-matched analysis based on age, sex, and comorbidities between AF and SR [hazard ratio: 3.80 (95% confidence interval 3.04-4.76)]. Independent risk factors associated with incident AFMR were age ≥65 years, female sex, LAVI, and DD in both AF and SR, in addition to rate (vs. rhythm) control in AF. Incident AFMR was independently associated with all-cause death in both groups (both P < 0.001). CONCLUSIONS: AF conferred a three-fold increase in the risk of incident AFMR. DD, older age, left atrial size, and female sex were independent risk factors in both SR and AF, while rhythm control was protective. AFMR was universally associated with worse mortality.

Fate of concomitant tricuspid regurgitation in patients undergoing coronary artery bypass grafting.

OBJECTIVE: Owing to a lack of supportive data, tricuspid regurgitation (TR) is usually not addressed in patients undergoing coronary artery bypass grafting (CABG). Here we evaluated changes in TR degrees over time and its impact on survival in patients undergoing CABG. METHODS: We reviewed the data of 9726 patients who underwent isolated CABG between January 2000 and January 2021. According to preoperative TR severity, patients were stratified into nonsignificant (none to trivial, mild) and significant (moderate to severe) TR groups. We excluded patients who had undergone previous tricuspid valve surgery, pacemaker placement, and concomitant valve or ablative surgery. Propensity score matching and Cox proportional hazards models were used to identify associations between TR grade and the primary outcome of all-cause mortality. The secondary outcome was change in TR severity on the last echocardiogram. RESULTS: After propensity score matching, 380 patients in each group were identified. At baseline, 359 patients had moderate TR (94.5%) and 21 (5.5%) had severe TR. On the last follow-up echocardiogram, TR had improved in 40.5% of the patients in the significant TR group. Kaplan-Meier survival curves showed significantly lower survival in patients with significant preoperative TR compared to those with nonsignificant TR (P < .001). After adjusting for other confounders, survival was no worse in the patients with significant TR group (hazard ratio, 1.05; 95% confidence interval, 0.80-1.38; P = .70). CONCLUSIONS: Significant preoperative TR improved in 40.5% of patients after isolated CABG. After adjusting for other factors, significant TR did not affect long-term survival.