Novel echocardiographic markers for left ventricular filling pressure prediction in heart failure with preserved ejection fraction (ECHO-PREDICT): a prospective cross-sectional study

Heart failure with preserved ejection fraction is a complex clinical syndrome associated with a high level of morbidity and mortality, constituting 56% of heart failure cases and showing an increasing prevalence. The E/Ea ratio, used for echocardiographic assessment of left ventricular (LV) filling pressure, has been commonly recommended as a noninvasive measure. However, its validity lacks robust prospective validation in patients with preserved LV ejection fraction, and its accuracy has been questioned in comparison to patients with reduced LV ejection fraction. The objective of this study was to evaluate the accuracy of novel echocardiographic markers incorporating peak E velocity, left atrial volume index (LAVi), and pulmonary artery systolic pressure (PAP) for noninvasive estimation of LV end-diastolic pressure (LVEDP) against invasive measurement. In this cross-sectional study conducted at a tertiary care hospital, a sample size of 122 participants was utilized. Statistical analyses including independent samples t-test, χ2 test, and linear regression analysis were employed to explore correlations and predict outcomes. The results indicated that Group 1 (LVEDP <20 mmHg) had a mean age of 59.25 years, while Group 2 (LVEDP >20 mmHg) had a mean age of 56.93 years. Mitral E velocity positively predicted LVEDP, while Mitral E/A ratio showed a negative association. Notably, (E+PAP)/2, (E+LAVi)/2, and Mitral E exhibited good discriminative ability, with respective area under the curve values of 0.840, 0.900, and 0.854. (E+LAVi)/2 demonstrated the highest discriminatory power, with a threshold of 40.100, yielding high sensitivity (0.971) but relatively low specificity (0.302) in predicting LVEDP greater than 20. These findings emphasize the accuracy and utility of combining diastolic variables and peak E velocity as markers for left ventricular filling pressure in patients with a high burden of cardiac disease. Additionally, the study highlights the importance of these parameters in assessing cardiac abnormalities and supports the potential of novel echocardiographic parameters, particularly (E+LAVi)/2, in predicting LVEDP greater than 20. Further research is warranted to validate and explore the prognostic implications of these parameters in larger patient populations, ultimately improving the diagnosis and management of cardiac disease and enhancing clinical outcomes.

Strategic multimodal non-invasive assessment of cardiac performance in patients with heart failure

AIMS

Although various non-invasive cardiac examinations are known to be predictive of long-term outcomes in patients with heart failure (HF), combining them properly would provide synergism. We aimed to show that non-invasive cardiac assessments targeting left ventricular filling pressure (LVFP), left atrial remodelling, and exercise capacity would provide better prognostication in combination.

METHODS AND RESULTS

This prospective observational study included consecutive hospitalized stage A-C HF patients evaluated with N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiography including two-dimensional speckle tracking, and cardiopulmonary exercise testing. According to NT-proBNP and echocardiographic semi-quantitative LVFP grading (Echo-LVFP), patients were classified into three LVFP groups: normal range of both Echo-LVFP and NT-proBNP (Group 1), normal range of Echo-LVFP but elevated NT-proBNP (Group 2), and elevated Echo-LVFP and NT-proBNP (Group 3). The adverse outcome was defined as a composite of cardiovascular death, non-fatal acute coronary syndrome, acute stroke, or HF-related hospitalization. Among 224 HF patients (mean age of 63.8 ± 11.6 years, 158 men) analysed, 160 (71.4%) had ischaemic aetiology. During the follow-up of 18.6 ± 9.8 months, event-free survival in Group 2 (n = 56, age of 65.4 ± 12.4) was better than that in Group 3 (n = 45, age of 68.5 ± 11.5) but worse than that in Group 1 (n = 123, mean age of 61.4 ± 10.5) (log-rank P < 0.001). Mechanical left atrial dysfunction (peak longitudinal strain <28%) (adjusted hazard ratio 5.69, 95% confidence interval 1.06-4.48) and limited exercise capacity (peak VO₂ per +5 mL/kg/min) (adjusted hazard ratio 0.63, 95% confidence interval 0.46-0.87) were also predictable adverse outcomes. Serial addition of peak VO₂ and left atrial strain to the model incrementally enhanced the predictive power of LVFP-based risk stratification for adverse outcomes.

CONCLUSIONS

The combination of NT-proBNP and Echo-LVFP could be used to predict adverse outcomes in patients with HF of various stages. Left atrial mechanics and exercise capacity are incremental to prognostication. Non-invasive test findings could be strategically combined to provide an integrative profile of cardiac performance.

An Artificial Intelligence Approach to Guiding the Management of Heart Failure Patients Using Predictive Models: A Systematic Review

Heart failure (HF) is one of the leading causes of mortality and hospitalization worldwide. The accurate prediction of mortality and readmission risk provides crucial information for guiding decision making. Unfortunately, traditional predictive models reached modest accuracy in HF populations. We therefore aimed to present predictive models based on machine learning (ML) techniques in HF patients that were externally validated. We searched four databases and the reference lists of the included papers to identify studies in which HF patient data were used to create a predictive model. Literature screening was conducted in Academic Search Ultimate, ERIC, Health Source Nursing/Academic Edition and MEDLINE. The protocol of the current systematic review was registered in the PROSPERO database with the registration number CRD42022344855. We considered all types of outcomes: mortality, rehospitalization, response to treatment and medication adherence. The area under the receiver operating characteristic curve (AUC) was used as the comparator parameter. The literature search yielded 1649 studies, of which 9 were included in the final analysis. The AUCs for the machine learning models ranged from 0.6494 to 0.913 in independent datasets, whereas the AUCs for statistical predictive scores ranged from 0.622 to 0.806. Our study showed an increasing number of ML predictive models concerning HF populations, although external validation remains infrequent. However, our findings revealed that ML approaches can outperform conventional risk scores and may play important role in HF management.

From left ventricular ejection fraction to cardiac hemodynamics: role of echocardiography in evaluating patients with heart failure

In clinical practice heart failure (HF) patients are generally classified on the basis of left ventricular (LV) ejection fraction. This approach, however, has important limitations. According to the definition of HF as a clinical syndrome that results from any impairment of LV filling or ejection of blood, a more articulated hemodynamic categorization of HF patients taking into account both LV forward flow and filling pressure would be desirable. However, the reliability of hemodynamic measures using echocardiographic techniques, which are the most used in current clinical practice for evaluation of HF patients, needs to be clarified. The aim of this article, therefore, is to verify whether echocardiography has acceptable feasibility, accuracy and reproducibility for the noninvasive evaluation of LV hemodynamics. This evaluation is necessary to progress to a hemodynamic characterization of HF patients that would ultimately overcome the HF classification based on ejection fraction.

Machine learning versus conventional clinical methods in guiding management of heart failure patients-a systematic review

Machine learning (ML) algorithms “learn” information directly from data, and their performance improves proportionally with the number of high-quality samples. The aim of our systematic review is to present the state of the art regarding the implementation of ML techniques in the management of heart failure (HF) patients. We manually searched MEDLINE and Cochrane databases as well the reference lists of the relevant review studies and included studies. Our search retrieved 122 relevant studies. These studies mainly refer to (a) the role of ML in the classification of HF patients into distinct categories which may require a different treatment strategy, (b) discrimination of HF patients from the healthy population or other diseases, (c) prediction of HF outcomes, (d) identification of HF patients from electronic records and identification of HF patients with similar characteristics who may benefit form a similar treatment strategy, (e) supporting the extraction of important data from clinical notes, and (f) prediction of outcomes in HF populations with implantable devices (left ventricular assist device, cardiac resynchronization therapy). We concluded that ML techniques may play an important role for the efficient construction of methodologies for diagnosis, management, and prediction of outcomes in HF patients.

Diagnostic value of echocardiographic markers for diastolic dysfunction and heart failure with preserved ejection fraction

This study aimed to evaluate the diagnostic performance of echocardiographic markers of heart failure with preserved ejection fraction (HFpEF) and left ventricular diastolic dysfunction (LVDD) in comparison with the gold standard of cardiac catheterization. Diagnosing HFpEF is challenging, as symptoms are non-specific and often absent at rest. A clear need exists for sensitive echocardiographic markers to diagnose HFpEF. We systematically searched for studies testing the diagnostic value of novel echocardiographic markers for HFpEF and LVDD. Two investigators independently reviewed the studies and assessed the risk of bias. Results were meta-analysed when four or more studies reported a similar diagnostic measure. Of 353 studies, 20 fulfilled the eligibility criteria. The risk of bias was high especially in the patients' selection domain. The highest diagnostic performance was demonstrated by a multivariable model combining echocardiographic, clinical and arterial function markers with an area under the curve of 0.95 (95% CI, 0.89-0.98). A meta-analysis of four studies indicated a reasonable diagnostic performance for left atrial strain with an AUC of 0.83 (0.70-0.95), a specificity of 93% (95% CI, 90-97%) and a sensitivity of 77% (95% CI, 59-96%). Moreover, the addition of exercise E/e' improved the sensitivity of HFpEF diagnostic algorithms up to 90%, compared with 60 and 34% of guidelines alone. Despite the heterogeneity of the included studies, this review supported the current multivariable-based approach for the diagnosis of HFpEF and LVDD and showed a potential diagnostic role for exercise echocardiography and left atrial strain. Larger well-designed studies are needed to evaluate the incremental value of novel diagnostic tools to current diagnostic algorithms.

Peak Oxygen Uptake Recovery Delay After Maximal Exercise in Patients With Heart Failure

PURPOSE

Peak oxygen uptake recovery delay (V˙o2peakRD), measured as the time until post-exercise oxygen uptake (V˙o2) decreases below V˙o2peak following maximal cardiopulmonary exercise testing (CPX), has been recognized as an abnormal response, associated with reduced cardiac output reserve during exercise in patients with heart failure (HF). In the current study we examined the association of V˙o2peakRD during routine CPX testing of patients with symptomatic HF across a wide range of left ventricular ejection fraction (LVEF) values with clinical biomarkers.

METHODS

In this retrospective study, 80 clinically stable symptomatic HF patients across a wide range of LVEF at our institution were evaluated that put forth a minimally acceptable effort during CPX testing (respiratory exchange ratio ≥ 1.00). The V˙o2peakRD was measured in 10-sec intervals following maximal CPX testing. Markers of elevated cardiac filling pressures (N-terminal pro-brain natriuretic peptide [NTproBNP] and echocardio-Doppler E/e') and other key CPX parameters were explored for their association with V˙o2peakRD.

RESULTS

The mean V˙o2peakRD and V˙o2peak were 10 (interquartile range 10, 40) sec and 13.9 (11.6, 16.4) mL· kg · min, respectively. V˙o2peakRD demonstrated a positive linear trend with serum NTproBNP levels and E/e' (TJT = 1239.500, z = 2.634, P < .01; TJT = 1081.000, z = 2.046, P = .04, respectively).

CONCLUSION

Prolonged V˙o2peakRD following exercise is associated with markers of greater disease severity in patients with HF.

Hemodynamic Validation of the E/e' Ratio as a Measure of Left Ventricular Filling Pressure in Patients With Non-ST Elevation Myocardial Infarction

The E/e' ratio has an established role in the assessment of left ventricular filling pressure (LVFP) in stable patients, but its accuracy in acute myocardial ischemia is less well established. The aim of this study was to validate the relation between the E/e' ratio and invasively measured LVFP in patients with non-ST elevation myocardial infarction (NSTEMI). A total of 120 unselected patients with NSTEMI underwent cardiac catheterization with measurement of left ventricular end-diastolic pressure (LVEDP; elevated ≥15 mm Hg) and Doppler echocardiography with either simultaneous (n = 30) or same-day (n = 90) measurement of E/e'. Patients were aged 64.1 ± 11.8 years, 72% were male and mean left ventricular ejection fraction was 48.0 ± 20.9%. Septal, lateral, and average E/e' ratios all showed a significant correlation with LVEDP (Pearson's r: 0.42, 0.43, 0.48, respectively [all p <0.001]). Receiver operating characteristics curves showed an area under the curve of 0.72, 0.72, and 0.75 (all p <0.001) for septal, lateral, and average E/e', respectively. The sensitivity, specificity, positive (PPV), and negative (NPV) predictive values for the guideline-recommended threshold of average E/e' >14 for elevated LVEDP was 27%, 93%, 79%, and 44%, respectively. Utilizing lower E/e' boundaries of 6, 7, and 8 for lateral, average, and medial E/e', respectively, improved the NPV to ≥80% for each parameter. In conclusion, the E/e' ratio is a robust measure of LVFP during acute NSTEMI using upper and lower thresholds to achieve a high PPV and NPV, respectively, with the use of adjunctive guideline-recommend measures required in patients with nonconclusive E/e'.

Estimation of increased pulmonary wedge pressure by an algorithm based on noninvasively measured pulmonary diastolic pressure in cardiac patients independent of left ventricular ejection fraction

AIM

Pulmonary artery diastolic pressure (PADP) correlates closely with pulmonary wedge pressure (PAWP); therefore, we sought to evaluate whether an algorithm based on PADP assessment by the Doppler pulmonary regurgitation (PR) end-diastolic gradient (PRG) may aid in estimating increased PAWP in cardiac patients with reduced or preserved left ventricular (LV) ejection fraction (EF).

METHODS AND RESULTS

Right heart catheterization, with estimation of PAWP, right atrial pressure (RAP), PADP, and Doppler echocardiography, was carried out in 183 patients with coronary artery disease (n = 63), dilated cardiomyopathy (n = 52), or aortic stenosis (n = 68). One-hundred and seventeen patients had LV EF <50%. We measured the pressure gradients across the tricuspid and pulmonary valves from tricuspid regurgitation (TRV) and PR velocities. Doppler-estimated PADP (e-PADP) was obtained by adding the estimated RAP to PRG. An algorithm based on e-PADP to predict PAWP, that included TRV, left atrial volume index, and mitral E/A, was developed and validated in derivation (n = 90) and validation (n = 93) subgroups. Both invasive PADP (r = .92, P < .001) and e-PADP (r = .72, P < .001) correlated closely with PAWP, and e-PADP predicted PAWP (AUC: 0.85, CI: 0.79-0.91) with a 94% positive predictive value (PPV) and a 55% negative predictive value (NPV), after exclusion of five patients with precapillary pulmonary hypertension. The e-PADP-based algorithm predicted PAWP with higher accuracy (PPV = 94%; NPV = 67%; accuracy = 85%; kappa: 0.65, P < .001) than the ASE-EACVI 2016 recommendations (PPV = 97%; NPV = 47%; accuracy = 68% undetermined = 18.9%; kappa: 0.15, P < .001).

CONCLUSIONS

An algorithm based on noninvasively e-PADP can accurately predict increased PAWP in patients with cardiac disease and reduced or preserved LV EF.

Compromised left atrial function and increased size predict raised cavity pressure: a systematic review and meta-analysis

AIM

This meta-analysis assesses left atrial (LA) cavity and myocardial function measurements that predict pulmonary capillary wedge pressure (PCWP).

METHODS

PubMed-MEDLINE, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry were searched up to December 2018 for studies on the relationship of LA diameter, LA indexed volume (LAVI max, LAVI min), peak atrial longitudinal (PALS), peak atrial contraction (PACS) strain and total emptying fraction (LAEF) with PCWP. Eighteen studies with 1343 patients were included. Summary sensitivity and specificity (with 95% CI) for evaluation of diagnostic accuracy and the best cut-off values for different LA indices in predicting raised PCWP were estimated using summary receiver operating characteristic analysis.

RESULTS

The pooled analysis showed association between PCWP and LA diameter: Cohen's d = 0·87, LAVI max: d = 0·92 and LAVI min: d = 1·0 (P<0·001 for all). A stronger correlation was found between PCWP and PALS: d = 1·26, and PACS: d = 1·62, total EF d = 1·22 (P<0·0001 for all). PALS ≤19% had a summary sensitivity of 80% (65-90) and summary specificity of 77% (52-92), positive likelihood ratio (LR+) 3·74, negative likelihood ratio (LR-) <0·25 and DOR > 15·1 whereas LAVI ≥34 ml m^-2 had summary sensitivity of 75% (55-89) and summary specificity 77% (57-90), with LR+ >3, LR- 0·32 and DOR >10·1.

CONCLUSIONS

Compromised LA myocardial function and increased size predict raised cavity pressure. These results should assist in optimum follow-up of patients with fluctuating LA pressure.

Relation of Hepatic Fibrosis in Nonalcoholic Fatty Liver Disease to Left Ventricular Diastolic Function and Exercise Tolerance

The purpose of this study was to determine the relation between liver histology, exercise tolerance, and diastolic function in patients with nonalcoholic fatty liver disease (NAFLD). Myocardial remodeling and diastolic dysfunction have been associated with NAFLD. However, its physiological impact and relationship to the histological severity of NAFLD is not known. Cardiopulmonary exercise testing and stress echocardiography was performed in subjects with biopsy-confirmed NAFLD. Maximal aerobic exercise capacity (peak oxygen consumption [VO2]) was related to diastolic function (mitral annulus Doppler velocity e' and ratio of early diastolic filling pressure [E] to e' [E/e']) at rest and peak exercise. Autonomic dysfunction was determined from heart rate recovery after exercise. Independent predictors of cardiac function and exercise capacity were identified by multivariable regression. Thirty-six subjects (nonalcoholic fatty liver [NAFL  =  15], nonalcoholic steatohepatitis [NASH  =  21]) were enrolled. NASH was associated with impaired exercise capacity compared with NAFL (median peak VO2 17.0 [15.4, 18.9] vs 19.9 [17.4, 26.0], p  =  001); pVO2 declined with increasing fibrosis (F0  =  22.5, F1  =  19.9, F2  =  19.0, F3  =  16.6 ml·kg-1·min-1; p  =  0.01). Similarly, E/e' during exercise increased progressively with increasing fibrosis (F0  =  5.6, F1  =  6.5, F2  =  8.7, F3  =  9.8; P  =  0.02). Finally, heart rate recovery, a marker of autonomic function, was blunted in those with higher fibrosis stages (F0  =  25 [20, 30], F1  =  23 [17.5, 27.0], F2  =  17 [11.8, 21.5], F3  =  11 [8.5, 18.0] beats per minute; p <0.01). Fibrosis was an independent predictor of these functional outcomes. In conclusion, NASH is associated with impaired exercise capacity and diastolic dysfunction compared with NAFL. The severity of impairment is directly related to the severity of fibrosis stage in precirrhotic stages of NAFLD.

Echo- and B-Type Natriuretic Peptide-Guided Follow-Up versus Symptom-Guided Follow-Up: Comparison of the Outcome in Ambulatory Heart Failure Patients

Recent European Society of Cardiology and American Heart Association/American College of Cardiology Guidelines did not recommend biomarker-guided therapy in the management of heart failure (HF) patients. Combination of echo- and B-type natriuretic peptide (BNP) may be an alternative approach in guiding ambulatory HF management. Our aim was to determine whether a therapy guided by echo markers of left ventricular filling pressure (LVFP), lung ultrasound (LUS) assessment of B-lines, and BNP improves outcomes of HF patients. Consecutive outpatients with LV ejection fraction (EF) ≤ 50% have been prospectively enrolled. In Group I (n=224), follow-up was guided by echo and BNP with the goal of achieving E-wave deceleration time (EDT) ≥ 150 ms, tissue Doppler index E/e' < 13, B-line numbers < 15, and BNP ≤ 125 pg/ml or decrease >30%; in Group II (n=293), follow-up was clinically guided, while the remaining 277 patients (Group III) did not receive any dedicated follow-up. At 60 months, survival was 88% in Group I compared to 75% in Group II and 54% in Group III (χ ² 53.5; p < 0.0001). Survival curves exhibited statistically significant differences using Mantel-Cox analysis. The number needed to treat to spare one death was 7.9 (Group I versus Group II) and 3.8 (Group I versus Group III). At multivariate Cox regression analyses, major predictors of all-cause mortality were follow-up E/e' (HR: 1.05; p=0.0038) and BNP >125 pg/ml or decrease ≤30% (HR: 4.90; p=0.0054), while BNP > 125 pg/ml or decrease ≤30% and B-line numbers ≥15 were associated with the combined end point of death and HF hospitalization. Evidence-based HF treatment guided by serum biomarkers and ultrasound with the goal of reducing elevated BNP and LVFP, and resolving pulmonary congestion was associated with better clinical outcomes and can be valuable in guiding ambulatory HF management.

Optimizing Management of Heart Failure by Using Echo and Natriuretic Peptides in the Outpatient Unit

Chronic heart failure (HF) is an important public health problem and is associated with high morbidity, high mortality, and considerable healthcare costs. More than 90% of hospitalizations due to worsening HF result from elevations of left ventricular (LV) filling pressures and fluid overload, which are often accompanied by the increased synthesis and secretion of natriuretic peptides (NPs). Furthermore, persistently abnormal LV filling pressures and a rise in NP circulating levels are well known indicators of poor prognosis. Frequent office visits with the resulting evaluation and management are most often needed. The growing pressure from hospital readmissions in HF patients is shifting the focus of interest from traditionally symptom-guided care to a more specific patient-centered follow-up care based on clinical findings, BNP and echo. Recent studies supported the value of serial NP measurements and Doppler echocardiographic biomarkers of elevated LV filling pressures as tools to scrutinize patients with impending clinically overt HF. Therefore, combination of echo and pulsed-wave blood-flow and tissue Doppler with NPs appears valuable in guiding ambulatory HF management, since they are potentially useful to distinguish stable patients from those at high risk of decompensation.

Combining echo and natriuretic peptides to guide heart failure care in the outpatient setting: A position paper

BACKGROUND

Chronic heart failure (HF) is a relevant and growing public health problem. Although the prognosis has recently improved, it remains a lethal disease, with a mortality that equals or exceeds that of many malignancies. Furthermore, chronic HF is costly, representing a large and growing drain on healthcare resources.

METHODS

This narrative review is based on the material searched for and obtained via PubMed up to May 2017. The search terms we used were as follows: "heart failure, echocardiography, natriuretic peptides" in combination with "treatment, biomarkers, guidelines."

RESULTS

Recent studies have supported the value of natriuretic peptides (NPs) and Doppler echocardiographic biomarkers of increased left ventricular (LV) filling pressures or pulmonary congestion as tools to scrutinize patients with impending clinically overt HF. Therefore, combination of pulsed-wave tissue and blood flow Doppler with NPs appears valuable in guiding HF management in the outpatient setting. In as much as both the echo and the plasma levels of NPs may reflect the presence of fluid overload and elevations of LV filling pressures, integrating NP and echocardiographic biomarkers with clinical findings may help the cardiologist to identify high-risk patients, that is to recognize whether a patient is stable or the condition is likely to evolve into decompensated HF, to optimize treatment, to improve the prognosis and to reduce rehospitalization.

CONCLUSION

We discussed the rationale and the clinical significance of combining follow-up echo and NP assessment to guide management of ambulatory patients with chronic HF.

Severely Impaired Cardiorespiratory Fitness in Patients With Recently Decompensated Systolic Heart Failure

Hospital admission for decompensated heart failure marks a critical inflection point in a patient's health. Despite the improvement in signs or symptoms during hospitalization, patients have a high likelihood of readmission, reflecting a lack of resolution of the underlying condition. Surprisingly, no studies have characterized the cardiorespiratory fitness of such patients. Fifty-two patients (38 [73%] male, age 57 [52 to 65] years, left ventricular ejection fraction 31% [24 to 38]) underwent cardiopulmonary exercise testing 4 (1 to 10) days after hospital discharge, when stable and without overt signs of volume overload. Transthoracic Doppler echocardiography, measurement of N-terminal pro-B-natriuretic peptide, and quality of life were also assessed. Aerobic exercise capacity was severely reduced: peak oxygen consumption (pVO₂) was 14.1 (11.2 to 16.3) ml/kg/min. Ventilatory inefficiency as indicated by the minute ventilation carbon dioxide production relation (VE/VCO₂ slope) >30 and oxygen uptake efficiency slope <2.0 was noted in 41 (77%) and 39 (75%) patients, respectively. Forty-five (87%) patients had 1 of 2 high-risk features (pVO₂ < 14 ml/kg/min or VE/VCO₂ >30). Perceived functional capacity, measured by the Duke Activity Status Index, was also severely reduced and correlated with pVO2. N-terminal pro-B-natriuretic peptide levels and early transmitral velocity/early mitral annulus velocity (E/e') ratio at echocardiography showed a modest correlation with lower pVO₂. In conclusion, patients with recently decompensated systolic heart failure demonstrate severe impairment in cardiorespiratory fitness, severely limiting quality of life.

A New Statistical Method to Determine the Degree of Validity of Health Economic Model Outcomes against Empirical Data

BACKGROUND

The validation of health economic (HE) model outcomes against empirical data is of key importance. Although statistical testing seems applicable, guidelines for the validation of HE models lack guidance on statistical validation, and actual validation efforts often present subjective judgment of graphs and point estimates.

OBJECTIVES

To discuss the applicability of existing validation techniques and to present a new method for quantifying the degrees of validity statistically, which is useful for decision makers.

METHODS

A new Bayesian method is proposed to determine how well HE model outcomes compare with empirical data. Validity is based on a pre-established accuracy interval in which the model outcomes should fall. The method uses the outcomes of a probabilistic sensitivity analysis and results in a posterior distribution around the probability that HE model outcomes can be regarded as valid.

RESULTS

We use a published diabetes model (Modelling Integrated Care for Diabetes based on Observational data) to validate the outcome "number of patients who are on dialysis or with end-stage renal disease." Results indicate that a high probability of a valid outcome is associated with relatively wide accuracy intervals. In particular, 25% deviation from the observed outcome implied approximately 60% expected validity.

CONCLUSIONS

Current practice in HE model validation can be improved by using an alternative method based on assessing whether the model outcomes fit to empirical data at a predefined level of accuracy. This method has the advantage of assessing both model bias and parameter uncertainty and resulting in a quantitative measure of the degree of validity that penalizes models predicting the mean of an outcome correctly but with overly wide credible intervals.

Reliability of updated left ventricular diastolic function recommendations in predicting elevated left ventricular filling pressure and prognosis

An updated 2016 echocardiographic algorithm for diagnosing left ventricular (LV) diastolic dysfunction (DD) was recently proposed. We aimed to assess the reliability of the 2016 echocardiographic LVDD grading algorithm in predicting elevated LV filling pressure and clinical outcomes compared to the 2009 version.

METHODS

We retrospectively identified 460 consecutive patients without atrial fibrillation or significant mitral valve disease who underwent transthoracic echocardiography within 24 hours of elective heart catheterization. LV end-diastolic pressure (LVEDP) and the time constant of isovolumic pressure decay (Tau) were determined. The association between DD grading by 2009 LVDD Recommendations and 2016 Recommendations with hemodynamic parameters and all-cause mortality were compared.

RESULTS

The 2009 LVDD Recommendations classified 55 patients (12%) as having normal, 132 (29%) as grade 1, 156 (34%) as grade 2, and 117 (25%) as grade 3 DD. Based on 2016 Recommendations, 177 patients (38%) were normal, 50 (11%) were indeterminate, 124 (27%) patients were grade 1, 75 (16%) were grade 2, 26 (6%) were grade 3 DD, and 8 (2%) were cannot determine. The 2016 Recommendations had superior discriminatory accuracy in predicting LVEDP (P<.001) but were not superior in predicting Tau. During median follow-up of 416 days (interquartile range: 5 to 2004 days), 54 patients (12%) died. Significant DD by 2016 Recommendations was associated with higher risk of mortality (P=.039, subdistribution HR1.85 [95% CI, 1.03-3.33]) in multivariable competing risk regression.

CONCLUSIONS

The grading algorithm proposed by the 2016 LV diastolic dysfunction Recommendations detects elevated LVEDP and poor prognosis better than the 2009 Recommendations.

Diagnostic Accuracy of Tissue Doppler Index E/e' for Evaluating Left Ventricular Filling Pressure and Diastolic Dysfunction/Heart Failure With Preserved Ejection Fraction: A Systematic Review and Meta-Analysis

Background

Tissue Doppler index E/è is used clinically and in multidisciplinary research for estimation of left ventricular filling pressure (LVFP) and diastolic dysfunction (DD)/heart failure with preserved ejection fraction (HFpEF). Its diagnostic accuracy is not well studied.

Methods and Results

From the PubMed, Scopus, Embase, and Cochrane databases, we identified 24 studies reporting E/è and invasive LVFP in preserved EF (≥50%). In random‐effects models, E/è had poor to mediocre linear correlation with LVFP. Summary sensitivity and specificity (with 95% CIs) for the American Society of Echocardiography–recommended E/è cutoffs (lateral, mean, and septal, respectively) to identify elevated LVFP was estimated by using hierarchical summary receiver operating characteristic analysis. Summary sensitivity was 30% (9–48%), 37% (13–61%), and 24% (6–46%), and summary specificity was 92% (82–100%), 91% (80–99%), and 98% (92–100%). Positive likelihood ratio (LR+) was <5 for lateral and mean E/è. LR+ was slightly >10 for septal E/è obtained from 4 studies (cumulative sample size <220). For excluding elevated LVFP, summary sensitivity for E/è (lateral, mean, and septal, respectively) was 64% (38–86%), 36% (3–74%), and 50% (14–81%), while summary specificity was 73% (54–89%), 83% (49–100%), and 89% (66–100%). Because of data set limitations, meaningful inference for identifying HFpEF by using E/è could not be drawn. With the use of quality assessment tool for diagnostic accuracy studies (Quality Assessment of Diagnostic Accuracy Studies questionnaire), we found substantial risks of bias and/or applicability.

Conclusions

There is insufficient evidence to support that E/è can reliably estimate LVFP in preserved EF. The diagnostic accuracy of E/è to identify/exclude elevated LVFP and DD/HFpEF is limited and requires further validation in a well‐designed prospective clinical trial.

"Left ventricular filling pressure(s)" - Ambiguous and misleading terminology, best abandoned

The use of the terms "left ventricular filling pressure" and "left ventricular filling pressures" is widespread in the cardiology literature, but the meanings ascribed to these terms have not been consistent. Left ventricular end-diastolic pressure (LVEDP) and mean left atrial pressure (LAP) cannot be used interchangeably as they will often differ in magnitude in the presence of cardiac disease and they also have different clinical significance. LVEDP is the best pressure to use when considering left ventricular function, whereas mean LAP is the most relevant pressure when considering the tendency to pulmonary congestion. The mean LAP is also the most relevant pressure for determining whether pulmonary hypertension has a left heart (post-capillary) component. If only a left ventricular pressure tracing is available then a technique to measure the mean left ventricular diastolic pressure is the best option for estimating the mean LAP. If only right heart pressures are available then the pulmonary artery end-diastolic pressure will provide a reasonable estimate of LVEDP, but only when the heart and pulmonary circulation are normal. If there is mitral valve disease, left ventricular disease or pulmonary hypertension the LVEDP cannot be estimated from right heart pressures. The problem of the ambiguity of "filling pressure (s)" is readily solved by the abandonment of this term and the use of either LVEDP or mean LAP as appropriate.

Interatrial septum motion but not Doppler assessment predicts elevated pulmonary capillary wedge pressure in patients undergoing cardiac surgery

BACKGROUND

Left atrial pressure and its surrogate, pulmonary capillary wedge pressure (PCWP), are important for determining diastolic function. The role of transthoracic echocardiography (TTE) in assessing diastolic function is well established in awake subjects. The objective was to assess the accuracy of predicting PCWP by TTE and transesophageal echocardiography (TEE) during coronary artery surgery.

METHODS

In 27 adult patients undergoing on-pump coronary artery surgery, simultaneous echocardiographic and hemodynamic measurements were obtained immediately before anesthesia (TTE), after anesthesia and mechanical ventilation (TTE and TEE), during conduit harvest (TEE), and after separation from cardiopulmonary bypass (TEE).

RESULTS

Twenty patients had an ejection fraction (EF) of 0.5 or greater. With the exception of E/e' and S/D ratios, echocardiographic values changed over the echocardiographic studies. In patients with low EF, E velocity, deceleration time, pulmonary vein D, S/D, and E/e' ratios correlated well with PCWP before anesthesia. After induction of anesthesia using TTE or TEE, correlations were poor. In normal EF patients, correlations were poor for both TEE and TTE at all five stages. The sensitivity and specificity of echocardiographic values were not high enough to predict raised PCWP except for a fixed curve pattern of interatrial septum (area under the curve 0.89 for PCWP ≥ 17, and 0.98 for ≥ 18 mmHg) and S/D less than 1 (area under the curve 0.74 for PCWP ≥ 17, and 0.78 for ≥ 18 mmHg).

CONCLUSION

Doppler assessment of PCWP was neither sensitive nor specific enough to be clinically useful in anesthetized patients with mechanical ventilation. The fixed curve pattern of the interatrial septum was the best predictor of raised PCWP.

Implementation strategies of Systems Medicine in clinical research and home care for cardiovascular disease patients

Insights from the "-omics" science have recently emphasized the need to implement an overall strategy in medical research. Here, the development of Systems Medicine has been indicated as a potential tool for clinical translation of basic research discoveries. Systems Medicine also gives the opportunity of improving different steps in medical practice, from diagnosis to healthcare management, including clinical research. The development of Systems Medicine is still hampered however by several challenges, the main one being the development of computational tools adequate to record, analyze and share a large amount of disparate data. In addition, available informatics tools appear not yet fully suitable for the challenge because they are not standardized, not universally available, or with ethical/legal concerns. Cardiovascular diseases (CVD) are a very promising area for translating Systems Medicine into clinical practice. By developing clinically applied technologies, the collection and analysis of data may improve CV risk stratification and prediction. Standardized models for data recording and analysis can also greatly broaden data exchange, thus promoting a uniform management of CVD patients also useful for clinical research. This advance however requires a great organizational effort by both physicians and health institutions, as well as the overcoming of ethical problems. This narrative review aims at providing an update on the state-of-art knowledge in the area of Systems Medicine as applied to CVD, focusing on current critical issues, providing a road map for its practical implementation.

Left atrial size, chemosensitivity, and central sleep apnea in heart failure

BACKGROUND

Central sleep apnea (CSA) is common among patients with heart failure (HF) and is promoted by elevated CO2 chemosensitivity. Left atrial size is a marker of the hemodynamic severity of HF. The aim of this study was to determine if left atrial size predicts chemosensitivity to CO2 and CSA in patients with HF.

METHODS

Patients with HF with left ventricular ejection fraction ≤ 35% underwent polysomnography for detection of CSA, echocardiography, and measurement of CO2 chemosensitivity. CSA was defined as an apnea-hypopnea index (AHI) ≥ 15/h with ≥ 50% central apneic events. The relation of clinical and echocardiographic parameters to chemosensitivity and CSA were evaluated by linear regression, estimation of ORs, and receiver operator characteristics.

RESULTS

Of 46 subjects without OSA who had complete data for analysis, 25 had CSA. The only parameter that significantly correlated with chemosensitivity was left atrial volume index (LAVI) (r = 0.40, P < .01). LAVI was greater in those with CSA than those without CSA (59.2 mL/m2 vs 36.4 mL/m2, P < .001) and significantly correlated with log-transformed AHI (r = 0.46, P = .001). LAVI was the best predictor of CSA (area under the curve = 0.83). A LAVI ≤ 33 mL/m2 was associated with 22% risk for CSA, while LAVI ≥ 53 mL/m2 was associated with 92% risk for CSA.

CONCLUSIONS

Increased LAVI is associated with heightened CO2 chemosensitivity and greater frequency of CSA. LAVI may be useful to guide referral for polysomnography for detection of CSA in patients with HF.

Transthoracic echocardiographic parameters in the estimation of pulmonary capillary wedge pressure in patients with present or previous heart failure

Multiple echocardiographic criteria are routinely used for the estimation of left heart filling pressures. We assessed the predictive value of various echocardiographic parameters to estimate the left heart filling pressure and proposed a simplified approach for its evaluation. We collected the clinical, echocardiographic, and invasive hemodynamic data from 93 patients with heart failure who underwent right-sided heart catheterization and transthoracic echocardiography within a 24-hour period. Of these 93 patients, 57% had a left ventricular ejection fraction <50% and 69% had an elevated mean pulmonary capillary wedge pressure of ≥ 15 mm Hg. A mitral E/E' of ≥ 15 had a sensitivity of 55% but a specificity of 96%. A left atrial area of ≥ 20 cm(2) had a sensitivity of 66% and specificity of 89%. A deceleration time <140 ms had a sensitivity of 51% and specificity of 93% to predict a pulmonary capillary wedge pressure of ≥ 15 mm Hg. The combination of E/E' ≥ 15 ± left atrial area of ≥ 20 cm(2) ± deceleration time <140 ms provided a sensitivity of 92% and specificity of 85%. On multivariate analysis, the combination of E/E' ≥ 15, left atrial area of ≥ 20 cm(2), and deceleration time <140 ms was the most significant predictor of a pulmonary capillary wedge pressure of ≥ 15 mm Hg (odds ratio 48, 95% confidence interval 10 to 289, p <0.001). In conclusion, this simplified approach using 3 echocardiographic parameters provides an accurate and a practical approach for the routine estimation of the elevated left heart filling pressure.

[State of the art: new developments in cardiac imaging]

Cardiac imaging continues to reveal new anatomical and functional insights into heart disease. In echocardiography, both transesophageal and transthoracic three-dimensional imaging have been fully developed and optimized, and the value of the techniques that have increased our understanding of cardiac mechanics and ventricular function is well established. At the same time, the healthcare industry has released new devices onto the market which, although they are easier to use, have limitations that restrict their use for routine assessment. Tomography's diagnostic and prognostic value in coronary artery disease continues to increase while radiation exposure becomes progressively lower. With cardiac magnetic resonance imaging, myocardial injury and recovery in ischemic heart disease and following acute coronary syndrome can be monitored in exquisite detail. The emergence of new combined tomographic and gamma camera techniques, exclusively developed for nuclear cardiology, have improved the quality of investigations and reduced radiation exposure. The hybrid or fusion images produced by combining different techniques, such as nuclear cardiology techniques and tomography, promise an exciting future.