Borlaug, Barry A

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 Pulmonary regurgitation (PR) after reparative intervention for congenital heart disease has been studied extensively. However, the burden, distribution of causes, and outcome of PR in adults is unknown. The study aimed to evaluate the prevalence, types, and outcomes of moderate/severe PR in adults in the community setting. Methods and results A total of 398 adult residents of Olmsted County who had clinically indicated echocardiography 2004–2023 at Mayo Clinic, Rochester, and had moderate or severe PR were identified retrospectively. The median age was 77 years, 48% were females, and 61 (51%) had severe PR. The age- and sex-adjusted US prevalence was 0.11% (vs. 0.67% for ≥moderate tricuspid regurgitation). Moderate/severe PR was due to pulmonary hypertension in 77%, congenital/iatrogenic in 11%, primary pulmonary valve disease in 2% (88% due to carcinoid), and idiopathic isolated in 10%. In contrast, severe PR was due to congenital/iatrogenic disease in 52%, pulmonary hypertension in 39%, primary PR in 5%, and isolated idiopathic in 3%. The all-cause mortality rate per 100 person-year was 73 in primary (mostly carcinoid) PR, 16 in pulmonary hypertension–related PR (not different vs. propensity-matched patients without PR), and 6 in isolated idiopathic PR (not different vs. matched patients without PR). Conclusion Moderate or severe PR had a lower prevalence vs. TR. The most frequent cause was pulmonary hypertension for ≥moderate PR and congenital/iatrogenic for severe PR. Mortality in patients with acquired ≥moderate PR appeared to be related to the underlying cause, with no excess mortality compared with matched patients without PR. Whether specifically severe PR confers excess mortality requires future investigation.

BACKGROUND: Patients with Fontan palliation have reduced aerobic capacity because of impaired cardiac, pulmonary, and skeletal muscle function. However, the assessment of aerobic capacity in this population still relies on comparisons with people without cardiovascular disease rather than comparison with the expected aerobic capacity of other Fontan patients. The purpose of this study was to determine the expected aerobic capacity of adults with Fontan palliation. METHODS: Adults with Fontan palliation who underwent a cardiopulmonary exercise test at Mayo Clinic (2003–2023) were stratified into quartiles based on the predicted peak oxygen consumption (VO 2 ). We assessed the correlates of predicted peak VO 2 and the relationship between predicted peak VO 2 quartiles and cardiovascular outcomes (death/transplant). RESULTS: Of 323 patients (age, 29±9 years; 177 [55%] men), the median peak VO 2 was 19.1 (15.2–23.9) mL/kg per minute, and this corresponds to a predicted peak VO 2 of 51% (range, 19–88; interquartile range, 41–62). After multivariable adjustments, the correlates of predicted peak VO 2 were body mass index (β±SE, −2.61±0.95; 2.61% decrease in predicted peak VO 2 per 5 kg/m 2 increase in body mass index; P =0.009), systemic saturation (β±SE, 3.65±0.85; 3.65% increase in predicted peak VO 2 per 5% increase in oxygen saturation; P <0.001), and Fontan pressure (β±SE, −1.24±0.22; 1.24% decrease in predicted peak VO 2 per 1 mm Hg increase in Fontan pressures; P <0.001). There was a 47% increase in the risk for death/transplant from a higher predicted peak VO 2 quartile to the next lower quartile (adjusted hazard ratio, 1.47 [95% CI, 1.09–2.05]; P =0.01). CONCLUSIONS: The results of the current study would help calibrate the interpretation of exercise test data in adults with Fontan palliation and improve risk stratification in this population. It also underscores the need to maintain normal Fontan hemodynamics and body weight, which are important determinants of aerobic capacity.

BACKGROUND: Patients with heart failure with preserved ejection fraction and obesity have significant disability and frequent exacerbations of heart failure. We hypothesized that tirzepatide, a long-acting agonist of glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors, would improve a comprehensive suite of clinical end points, including measures of health status, functional capacity, quality of life, exercise tolerance, patient well-being, and medication burden, in these patients. METHODS: We randomized (double-blind) 731 patients with class II to IV heart failure, ejection fraction ≥50%, and body mass index ≥30 kg/m 2 to tirzepatide (titrated up to 15 mg SC weekly; n=364) or placebo (n=367) added to background therapy for a median of 104 weeks (quartile 1, 66; quartile 3, 126 weeks). The primary end points were whether tirzepatide reduced the combined risk of cardiovascular death or worsening heart failure and improved Kansas City Cardiomyopathy Questionnaire Clinical Summary Score. The current expanded analysis included sensitivity analyses of the primary end points, 6-minute walk distance, EQ-5D-5L health state index, Patient Global Impression of Severity Overall Health score, New York Heart Association class, use of heart failure medications, and a hierarchical composite based on all-cause death, worsening heart failure, and 52-week changes in Kansas City Cardiomyopathy Questionnaire Clinical Summary Score and 6-minute walk distance. RESULTS: Patients were 65.2±10.7 years of age; 53.8% (n=393) were female; body mass index was 38.2±6.7 kg/m 2 ; Kansas City Cardiomyopathy Questionnaire Clinical Summary Score was 53.5±18.5; 6-minute walk distance was 302.8±81.7 m; and 53% (n=388) had a worsening heart failure event in the previous 12 months. Compared with placebo, tirzepatide produced a consistent beneficial effect across all composites of death and worsening heart failure events, analyzed as time to first event (hazard ratios, 0.41–0.67). At 52 weeks, tirzepatide increased the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score by 6.9 points (95% CI, 3.3–10.6; P <0.001), 6-minute walk distance 18.3 meters (95% CI, 9.9–26.7; P <0.001), and EQ-5D-5L 0.06 (95% CI, 0.03–0.09; P <0.001). The tirzepatide group shifted to a more favorable Patient Global Impression of Severity Overall Health score (proportional odds ratio, 1.99 [95% CI, 1.44–2.76]) and New York Heart Association class (proportional odds ratio, 2.26 [95% CI, 1.54–3.31]; both P <0.001) and required fewer heart failure medications ( P =0.015). The broad spectrum of effects was reflected in benefits on the hierarchical composite (win ratio, 1.63 [95% CI, 1.17–2.28]; P =0.004). CONCLUSIONS: Tirzepatide produced a comprehensive, meaningful improvement in heart failure across multiple complementary domains; enhanced health status, quality of life, functional capacity, exercise tolerance, and well-being; and reduced symptoms and medication burden in patients with heart failure with preserved ejection fraction and obesity. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04847557.

BACKGROUND: Mechanisms of benefit with SGLT2is (sodium-glucose cotransporter-2 inhibitors) in heart failure (HF) remain incompletely characterized. Dapagliflozin alters ketone and fatty acid metabolism in HF with reduced ejection fraction though similar effects have not been observed in HF with preserved ejection fraction. We explore whether metabolic effects of SGLT2is vary across the left ventricular ejection fraction spectrum and their relationship with cardiometabolic end points in 2 randomized trials of dapagliflozin in HF. METHODS: Metabolomic profiling of 61 metabolites was performed in 527 participants from DEFINE-HF (Dapagliflozin Effects on Biomarkers, Symptoms and Functional Status in Patients With HF With Reduced Ejection Fraction) and PRESERVED-HF (Dapagliflozin in PRESERVED Ejection Fraction HF; 12-week, placebo-controlled trials of dapagliflozin in HF with reduced ejection fraction and HF with preserved ejection fraction, respectively). Linear regression was used to assess changes in principal components analysis–defined metabolite factors with treatment from baseline to 12 weeks, as well as the relationship between changes in metabolite clusters and HF-related end points. RESULTS: The mean age was 66±11 years, 43% were female, and 33% were self-identified as Black. Two principal components analysis–derived metabolite factors (which were comprised of ketone and short-/medium-chain acylcarnitines) increased with dapagliflozin compared with placebo. Ketosis (defined as 3-hydroxybutyrate >500 μM) was achieved in 4.5% with dapagliflozin versus 1.2% with placebo ( P =0.03). There were no appreciable treatment effects on amino acids, including branched-chain amino acids. Increases in several acylcarnitines were consistent across LVEF ( P interaction >0.10), whereas the ketogenic effect diminished at higher LVEF ( P interaction =0.01 for 3-hydroxybutyrate). Increases in metabolites reflecting mitochondrial dysfunction (particularly long-chain acylcarnitines) and aromatic amino acids and decreases in branched-chain amino acids were associated with worse HF-related outcomes in the overall cohort, with consistency across treatment and LVEF. CONCLUSIONS: SGLT2is demonstrate common (fatty acid) and distinct (ketogenic) metabolic signatures across the LVEF spectrum. Changes in key pathways related to fatty acid and amino acid metabolism are associated with HF-related end points and may serve as therapeutic targets across HF subtypes. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique Identifiers: NCT03030235 and NCT02653482.

Abstract Aims The effects of obesity on Fontan haemodynamics are poorly understood. Accordingly, we assessed its impact on exercise invasive haemodynamics and exercise capacity. Methods and results Seventy-seven adults post-Fontan undergoing exercise cardiac catheterization (supine cycle protocol) were retrospectively identified using an institutional database and categorized according to the presence of obesity [body mass index (BMI) &gt; 30 kg/m2] and overweight/normal BMI (BMI ≤ 30 kg/m2). There were 18 individuals with obesity (BMI 36.4 ± 3 kg/m2) and 59 with overweight/normal BMI (BMI 24.1 ± 3.6 kg/m2). Peak oxygen consumption (VO2) on non-invasive cardiopulmonary exercise testing was lower in patients with obesity (15.6 ± 3.5 vs. 19.6 ± 5.8 mL/kg/min, P = 0.04). At rest, systemic flow (Qs) [7.0 (4.8; 8.3) vs. 4.8 (3.9; 5.8) L/min, P = 0.001], pulmonary artery (PA) pressure (16.3 ± 3.5 vs. 13.1 ± 3.5 mmHg, P = 0.002), and PA wedge pressure (PAWP) (11.7 ± 4.4 vs. 8.9 ± 3.1 mmHg, P = 0.01) were higher, while arterial O2 saturation was lower [89.5% (86.5; 92.3) vs. 93% (90; 95)] in obesity compared with overweight/normal BMI. Similarly, patients with obesity had higher exercise PA pressure (29.7 ± 6.5 vs. 24.7 ± 6.8 mmHg, P = 0.01) and PAWP (23.0 ± 6.5 vs. 19.8 ± 7.3 mmHg, P = 0.047), but lower arterial O2 saturation [82.4 ± 7.0% vs. 89% (85; 92), P = 0.003]. Conclusion Adults post-Fontan with obesity have worse aerobic capacity, increased Qs, higher filling pressures, and decreased arterial O2 saturation compared with those with overweight/normal BMI, both at rest and during exercise, mirroring the findings observed in the obesity phenotype of heart failure with preserved ejection fraction. Whether treating obesity and its cardiometabolic sequelae in Fontan patients will improve haemodynamics and outcomes requires further study.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) is a major cause of morbidity and mortality in patients with type 2 diabetes (T2D). Acute increases in circulating levels of ketone body 3-hydroxybutyrate have beneficial acute hemodynamic effects in patients without T2D with chronic heart failure with reduced ejection fraction. However, the cardiovascular effects of prolonged oral ketone ester (KE) treatment in patients with T2D and HFpEF remain unknown. METHODS: A total of 24 patients with T2D and HFpEF completed a 6-week randomized, double-blind crossover study. All patients received 2 weeks of KE treatment (25 g D-ß-hydroxybutyrate-(R)-1,3-butanediol × 4 daily) and isocaloric and isovolumic placebo, separated by a 2-week washout period. At the end of each treatment period, patients underwent right heart catheterization, echocardiography, and blood samples at trough levels of intervention, and then during a 4-hour resting period after a single dose. A subsequent second dose was administered, followed by an exercise test. The primary end point was cardiac output during the 4-hour rest period. RESULTS: During the 4-hour resting period, circulating 3-hydroxybutyrate levels were 10-fold higher after KE treatment (1010±56 µmol/L; P <0.001) compared with placebo (91±55 µmol/L). Compared with placebo, KE treatment increased cardiac output by 0.2 L/min (95% CI, 0.1 to 0.3) during the 4-hour period and decreased pulmonary capillary wedge pressure at rest by 1 mm Hg (95% CI, –2 to 0) and at peak exercise by 5 mm Hg (95% CI, –9 to –1). KE treatment decreased the pressure-flow relationship (∆ pulmonary capillary wedge pressure/∆ cardiac output) significantly during exercise ( P <0.001) and increased stroke volume by 10 mL (95% CI, 0 to 20) at peak exercise. KE right-shifted the left ventricular end-diastolic pressure-volume relationship, suggestive of reduced left ventricular stiffness and improved compliance. Favorable hemodynamic responses of KE treatment were also observed in patients treated with sodium-glucose transporter-2 inhibitors and glucagon-like peptide-1 analogs. CONCLUSIONS: In patients with T2D and HFpEF, a 2-week oral KE treatment increased cardiac output and reduced cardiac filling pressures and ventricular stiffness. At peak exercise, KE treatment markedly decreased pulmonary capillary wedge pressure and improved pressure-flow relationship. Modulation of circulating ketone levels is a potential new treatment modality for patients with T2D and HFpEF. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique Identifier: NCT05236335.