Obokata, Masaru

Abstract Background and Aims Exercise stress echocardiography is recommended as an alternative to invasive testing for diagnosing heart failure with preserved ejection fraction (HFpEF), but an evidence-based operational framework guiding its application is lacking. Methods Patients with chronic unexplained dyspnoea underwent invasive haemodynamic exercise testing with simultaneous echocardiography to test the hypotheses that (i) the current diagnostic algorithms (H2FPEF, HFA-PEFF, and HFpEF-ABA scores) could be enhanced when combined with exercise echocardiography; and (ii) incorporating resting left atrial (LA) compliance (LA reservoir strain divided by E/e′) could further improve diagnostic triage, using separate cut points optimizing sensitivity and specificity. Findings were then validated in an international multicentre cohort. Results Of 482 patients, HFpEF was present in 386 and non-cardiac dyspnoea in 96. Sensitivity to detect HFpEF was only 55%–60% and accuracy 61%–67% using individual diagnostic scores with currently recommended exercise echocardiography. Addition of abnormal resting LA compliance to exercise echocardiography increased sensitivity to 84%–85% but increased the false-positive rate to 31%–43%. Applying separate cut points that optimize specificity and sensitivity (either exercise E/e′ ≥ 13.8 or resting LA compliance ≤1.6% to rule-in HFpEF; both exercise E/e′ < 7.2 and resting LA compliance >4.4% to rule-out HFpEF, remaining patients indeterminate who require invasive testing) improved sensitivity to 95%–99% among definitively classified patients and reduced the number of patients that require invasive exercise testing from ∼60% to ∼30%. Findings were replicated in a multicentre, international validation cohort of patients undergoing rest–exercise echocardiography and invasive exercise testing. Conclusions Currently used non-invasive approaches to HFpEF diagnosis have inadequate sensitivity, indicating that exercise echocardiography cannot supplant invasive testing. Addition of LA strain imaging with optimized rule-in or rule-out values improves diagnostic triage by expanding non-invasive rule-in/rule-out classifications while identifying patients who still require invasive testing in the evaluation of HFpEF.

BACKGROUND: Plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) is commonly used to diagnose heart failure with preserved ejection fraction (HFpEF), but its diagnostic performance in the ambulatory/outpatient setting is unknown because previous studies lacked objective reference standards. METHODS: Among patients with chronic dyspnea, diagnosis of HFpEF or noncardiac dyspnea was determined conclusively by exercise catheterization in a derivation cohort (n=414), multicenter validation cohort 1 (n=560), validation cohort 2 (n=207), and a nonobese Japanese validation cohort 3 (n=77). Optimal NT-proBNP cut points for HFpEF rule out (optimizing sensitivity) and rule in (optimizing specificity) were derived and tested, stratified by obesity and atrial fibrillation. Derived cut points were tested in 3 additional validation cohorts (cohorts 4–6) in whom HFpEF was diagnosed by resting catheterization only (n=260), previous hospitalization for heart failure (n=447), or exercise echocardiography (n=517), respectively. RESULTS: Current recommended rule-out NT-proBNP threshold <125 pg/mL had 82% sensitivity (95% CI, 77%–88%) with a body mass index (BMI) <35 kg/m 2 , decreasing to 67% (95% CI, 58%–77%) with a BMI ≥35 kg/m 2 . A lower rule-out NT-proBNP threshold <50 pg/mL displayed good sensitivity with a BMI <35 kg/m 2 (97% [95% CI, 95%–99%]), with a modest decline in sensitivity with a BMI ≥35 kg/m 2 (86% [95% CI, 79%–93%]); diagnostic thresholds were confirmed in validation cohorts 1 and 2 (91% [95% CI, 88%–95%] and 86% [95% CI, 80%–93%] with a BMI <35 kg/m 2 ; 80% [95% CI, 74%–87%] and 84% [95% CI, 74%–93%] with a BMI ≥35 kg/m 2 ). Current consensus age- and BMI-stratified rule-in thresholds demonstrated only 65% specificity (95% CI, 57%–72%). Rule-in NT-proBNP threshold ≥500 pg/mL had 85% specificity (95% CI, 78%–91%) with a BMI <35 kg/m 2 (87% [95% CI, 80%–94%] and 90% [95% CI, 81%–99%] in validation cohorts), with 100% specificity at a BMI ≥35 kg/m 2 (93% [95% CI, 81%–100%] and 100% in validation cohorts). With a BMI ≥35 kg/m 2 , lower rule-in thresholds (≥220 pg/mL) provided good specificity (88% [95% CI, 73%–100%]; 93% [95% CI, 81%–100%] and 100% in validation cohorts). Findings were consistent in validation cohorts 3 through 6 (sensitivity of <50 pg/mL, 93%–98%; specificity of ≥500 pg/mL, 82%–89%). NT-proBNP provided no incremental discrimination among patients with history of AF; ≥98% of patients with AF and dyspnea were found to have HFpEF in our cohorts. CONCLUSIONS: In patients with chronic unexplained dyspnea, current rule-in and rule-out NT-proBNP diagnostic thresholds lead to unacceptably high error rates, with important interactions by obesity and AF status. In our study, NT-proBNP provided little value in those with AF and dyspnea because the presence of AF is by itself a robust biomarker of HFpEF. Use of separate rule-in and rule-out diagnostic thresholds stratified by BMI reduces miscategorization and can guide more appropriate use of exercise testing for possible HFpEF.

Abstract Aims The diagnosis of heart failure with preserved ejection fraction (HFpEF) remains challenging based on resting assessments. Exercise echocardiography is often used to unmask abnormalities that develop during exercise, but the diagnostic criteria have not been standardized. This study aimed to elucidate how cardiologists utilize exercise echocardiography to diagnose HFpEF in real-world practice. Methods and results An international web-based survey involving 87 cardiologists was performed. We also performed a retrospective cross-sectional study to investigate the impact of different exercise echocardiographic diagnostic criteria in 652 dyspnoeic patients who underwent exercise echocardiography. The HFA-PEFF algorithm was the most commonly used exercise echocardiography criterion for HFpEF diagnoses (48%), followed by the ASE/EACVI criteria (24%) and other combinations of multiple parameters (22%). Among 652 patients, the proportion of HFpEF diagnosis varied substantially according to the criteria used ranging from 20.1% (ASE/EACVI criteria) to 44.3% (HFA-PEFF algorithm). Many cases (49.4–70.5%) remained indeterminate after exercise echocardiography, but only 41% of surveyed cardiologists would utilize exercise right heart catheterization to resolve an indeterminate result. Despite these diagnostic uncertainties, 54% of surveyed cardiologists would utilize exercise echocardiography results to initiate sodium–glucose co-transporter 2 inhibitors. Conclusion In real-world practice, exercise echocardiographic criteria utilized across cardiologists vary, which meaningfully impacts the frequency of HFpEF diagnoses, with indeterminate results being common. Despite these diagnostic uncertainties, many cardiologists initiate pharmacotherapy based on exercise echocardiography. The lack of consensus on universal diagnostic criteria for exercise echocardiography and approaches to indeterminate results may limit the delivery of evidence-based treatment for HFpEF.

Abstract Obesity and heart failure with preserved ejection fraction (HFpEF) represent two intermingling epidemics driving perhaps the greatest unmet health problem in cardiovascular medicine in the 21st century. Many patients with HFpEF are either overweight or obese, and recent data have shown that increased body fat and its attendant metabolic sequelae have widespread, protean effects systemically and on the cardiovascular system leading to symptomatic HFpEF. The paucity of effective therapies in HFpEF underscores the importance of understanding the distinct pathophysiological mechanisms of obese HFpEF to develop novel therapies. In this review, we summarize the current understanding of the cardiovascular and non-cardiovascular features of the obese phenotype of HFpEF, how increased adiposity might pathophysiologically contribute to the phenotype, and how these processes might be targeted therapeutically.

Abstract Aims Pulmonary hypertension (PH) and pulmonary vascular disease (PVD) are common and associated with adverse outcomes in left heart disease (LHD). This study sought to characterize the pathophysiology of PVD across the spectrum of PH in LHD. Methods and results Patients with PH-LHD [mean pulmonary artery (PA) pressure &gt;20 mmHg and PA wedge pressure (PAWP) ≥15 mmHg] and controls free of PH or LHD underwent invasive haemodynamic exercise testing with simultaneous echocardiography, expired air and blood gas analysis, and lung ultrasound in a prospective study. Patients with PH-LHD were divided into isolated post-capillary PH (IpcPH) and PVD [combined post- and pre-capillary PH (CpcPH)] based upon pulmonary vascular resistance (PVR &lt;3.0 or ≥3.0 WU). As compared with controls (n = 69) and IpcPH-LHD (n = 55), participants with CpcPH-LHD (n = 40) displayed poorer left atrial function and more severe right ventricular (RV) dysfunction at rest. With exercise, patients with CpcPH-LHD displayed similar PAWP to IpcPH-LHD, but more severe RV–PA uncoupling, greater ventricular interaction, and more severe impairments in cardiac output, O2 delivery, and peak O2 consumption. Despite higher PVR, participants with CpcPH developed more severe lung congestion compared with both IpcPH-LHD and controls, which was associated lower arterial O2 tension, reduced alveolar ventilation, decreased pulmonary O2 diffusion, and greater ventilation-perfusion mismatch. Conclusions Pulmonary vascular disease in LHD is associated with a distinct pathophysiologic signature marked by greater exercise-induced lung congestion, arterial hypoxaemia, RV–PA uncoupling, ventricular interdependence, and impairment in O2 delivery, impairing aerobic capacity. Further study is required to identify novel treatments targeting the pulmonary vasculature in PH-LHD.

Abstract Background A substantial proportion of patients with heart failure (HF) with preserved ejection fraction (HFpEF) present with normal natriuretic peptide (NP) levels. The pathophysiology and natural history for this phenotype remain unclear. Methods and results Consecutive subjects undergoing invasive cardiopulmonary exercise testing for unexplained dyspnoea at Mayo Clinic in 2006–18 were studied. Heart failure with preserved ejection fraction was defined as a pulmonary arterial wedge pressure (PAWP) ≥15 mmHg (rest) or ≥25 mmHg (exercise). Patients with HFpEF and normal NP [N-terminal of the pro-hormone B-type natriuretic peptide (NT-proBNP) &lt; 125 ng/L] were compared with HFpEF with high NP (NT-proBNP ≥ 125 ng/L) and controls with normal haemodynamics. Patients with HFpEF and normal (n = 157) vs. high NP (n = 263) were younger, yet older than controls (n = 161), with an intermediate comorbidity profile. Normal NP HFpEF was associated with more left ventricular hypertrophy and worse diastolic function compared with controls, but better diastolic function, lower left atrial volumes, superior right ventricular function, and less mitral/tricuspid regurgitation compared with high NP HFpEF. Cardiac output (CO) reserve with exercise was preserved in normal NP HFpEF [101% predicted, interquartile range (IQR): 75–124%], but this was achieved only at the cost of higher left ventricular transmural pressure (LVTMP) (14 ± 6 mmHg vs. 7 ± 4 mmHg in controls, P &lt; 0.001). In contrast, CO reserve was decreased in high NP HFpEF (85% predicted, IQR: 59–109%), with lower LVTMP (10 ± 8 mmHg) compared with normal NP HFpEF (P &lt; 0.001), despite similar PAWP. Patients with high NP HFpEF displayed the highest event rates, but normal NP HFpEF still had 2.7-fold higher risk for mortality or HF readmissions compared with controls (hazard ratio: 2.74, 95% confidence interval: 1.02–7.32) after adjusting for age, sex, and body mass index. Conclusion Patients with HFpEF and normal NP display mild diastolic dysfunction and preserved CO reserve during exercise, despite marked elevation in filling pressures. While clinical outcomes are not as poor compared with patients with high NP, patients with normal NP HFpEF exhibit increased risk of death or HF readmissions compared with patients without HF, emphasizing the importance of this phenotype.

Abstract Aims Central obesity is a major risk factor for heart failure with preserved ejection fraction (HFpEF), particularly in women, but the mechanisms remain unclear. We hypothesized that sex-specific differences in visceral adipose tissue (VAT) content would differentially relate to haemodynamic severity of HFpEF in women and men. Methods and results Abdominal computed tomography (CT) and invasive haemodynamic exercise testing were performed in 105 subjects with HFpEF (63 women) and 105 age-, sex-, and body mass index-matched controls. Visceral adipose tissue area was quantified by CT. As compared with control women, VAT area was 34% higher in women with HFpEF (186 ± 112 vs. 139 ± 72 cm2, P = 0.006), while VAT area was not significantly different in men with or without HFpEF (294 ± 158 vs. 252 ± 92 cm2, P = 0.1). During exercise, pulmonary capillary wedge pressure (PCWP) increased markedly and to similar extent in both men and women with HFpEF. Women with increased VAT area displayed 33% higher PCWP during exercise compared with women with normal VAT area (28 ± 10 vs. 21 ± 10 mmHg, P = 0.001), whereas exercise PCWP was similar in men with or without excess VAT (24 ± 9 vs. 25 ± 6, P = 0.89). In women, each 100 cm2 increase in VAT area was associated with a 4.0 mmHg higher PCWP (95% CI 2.1, 6.0 mmHg; P &lt; 0.0001), but there was no such relationship in men (interaction P = 0.009). Conclusions These data suggest that accumulation of excess VAT plays a distinct and important role in the pathophysiology of HFpEF preferentially in women. Further research is needed to better understand the mechanisms and treatment implications for visceral fat in HFpEF.

Abstract Aims Lung congestion in patients with heart failure (HF) has traditionally been treated using interventions that reduce pulmonary capillary hydrostatic pressure. The transient receptor potential vanilloid 4 (TRPV4) channel regulates fluid transit across the pulmonary capillary-interface, and represents a novel target to reduce lung water, independent of pulmonary capillary hypertension. This pilot study examined the safety and potential efficacy of TRPV4 blockade as a novel treatment for HF. Methods and results In this randomized, double-blind, placebo-controlled crossover pilot trial, 11 subjects with chronic, compensated HF were treated with a novel TRPV4 antagonist (GSK2798745) or placebo. The primary endpoint was lung diffusing capacity for carbon monoxide (DLCO) after 7 days of treatment with GSK2798745 as compared to placebo. Secondary endpoints included additional diffusion parameters, spirometry and safety assessments. Compared to placebo, treatment with GSK2798745 resulted in a trend to improvement in DLCO (placebo: −0.336 mL/mmHg/min; GSK2798745: +0.458 mL/mmHg/min; treatment difference: +0.793 mL/mmHg/min; 95% confidence interval: −0.925 to 2.512) that was not statistically significant. GSK2798745 was well-tolerated with no serious adverse events. Conclusion In this pilot trial, GSK2798745 was found to be safe and well-tolerated, with a trend toward improved gas transfer. Further investigation is warranted in larger studies to determine whether treatment with TRPV4 antagonists or alternative treatments targeting capillary permeability might be effective to improve lung congestion, pulmonary gas transfer and clinical status in patients with acute or chronic HF.

Abstract Aims Patient-reported quality of life (QOL) is a highly prognostic and clinically relevant endpoint in patients with heart failure (HF) with preserved ejection fraction (HFpEF). The relationships between QOL and different markers of HF severity remain unclear, particularly as they relate to functional capacity and directly measured activity levels. We hypothesized that QOL would demonstrate a stronger relationship with measures of exercise capacity and adiposity compared to other disease measures. Methods and results This is a secondary analysis of the National Heart, Lung, and Blood Institute-sponsored RELAX, NEAT-HFpEF and INDIE-HFpEF trials to determine the relationships between QOL (assessed by the Kansas City Cardiomyopathy Questionnaire and Minnesota Living with Heart Failure Questionnaire) and different domains reflecting HF severity, including maximal aerobic capacity (peak oxygen consumption), submaximal exercise capacity (6-min walk distance), volume of daily activity (accelerometry), physician-estimated functional class, resting echocardiography, and plasma natriuretic peptide levels. A total of 408 unique patients with chronic HFpEF were split into tertiles of QOL scores defined as QOLworst, QOLintermediate, QOLbest. The QOLworst HFpEF group was youngest, with a higher body mass index, greater prevalence of class II obesity and diabetes, and the lowest N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. After adjustment for age, sex and body mass index, poorer QOL was associated with worse physical capacity and activity levels, assessed by peak oxygen consumption, 6-min walk distance and actigraphy, but was not associated with NT-proBNP or indices from resting echocardiography. QOL was similarly reduced in patients with and without prior HF hospitalization. Conclusions Quality of life in HFpEF is poorest in patients who are young, obese and have diabetes, and is more robustly tied to measures reflecting functional capacity and daily activity levels rather than elevations in NT-proBNP or prior HF hospitalization. These findings have major implications for the understanding of QOL in HFpEF and for the design of future clinical trials targeting symptom improvement in HFpEF. Clinical Trial Registration: RELAX, NCT00763867; NEAT-HFpEF, NCT02053493; INDIE-HFpEF, NCT02742129.