Andersen, Mads Jønsson

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.

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.

Background Haemodynamic exercise testing is important for evaluating patients with dyspnoea on exertion and preserved ejection fraction. Despite very different pathologies, patients with pressure (aortic stenosis (AS)) and volume (mitral regurgitation (MR)) overload and diastolic dysfunction after recent acute myocardial infarction (AMI) reach similar filling pressure levels with exercise. The pressure–flow relationships (the association between change in cardiac output (∆CO) and change in pulmonary arterial wedge pressure (∆PAWP) may provide insight into haemodynamic adaptation to exercise in these groups. Methods and results One hundred sixty-eight subjects aged >50 years with a left ventricular ejection fraction of ≥50% underwent invasive exercise testing. They were enrolled in four different studies: AS (40 patients), AMI (52 patients), MR (43 patients) and 33 healthy subjects. Haemodynamic data were measured at rest, at 25 W, 75 W and at peak exercise. In all groups, PAWP increased with exercise. The greatest increase was observed in patients with AMI (from 12.7±3.9 mm Hg to 33.1±8.2 mm Hg, p<0.0001) and patients with AS (from 11.8±3.9 mm Hg to 31.4±6.1 mm Hg, p<0.0001), and the smallest was observed in healthy subjects (from 8.3±2.4 mm Hg to 21.1±7.5 mm Hg, p<0.0001). In all groups, the relative pressure increase was greatest at the beginning of the exercise. CO increased most in healthy patients (from 5.3±1.1 to 16.0±3.0 L/min, p<0.0001) and least in patients with AS (from 5.3±1.2 L/min to 12.4±2.6 L/min, p<0.0001). The pressure–flow relationships (∆PAWP/∆CO) and differed among groups (p = 0.02). In all groups, the pressure–flow relationship was steepest in the initial phase of the exercise test. The AMI and AS groups (2.3±1.2 mm Hg/L/min and 3.0±1.3 mm Hg/L/min, AMI and AS, respectively) had the largest overall pressure–flow relationship; the healthy group had the smallest initially and at peak exercise (1.3±1.1 mm Hg/L/min) followed by MR group (1.9±1.4 mm Hg/L/min). Conclusion The pressure–flow relationship was steepest in the initial phase of the exercise test in all groups. The pressure–flow relationship differs between groups. Trial registration numbers NCT01974557 , NCT01046838 , NCT02961647 and NCT02395107 .

Objective To assess the association between cardiac morphology and function assessed with cardiac MRI (CMRI) and haemodynamics at rest and during exercise in patients with primary mitral regurgitation (MR). Methods In an observational study, subjects with significant primary MR (N = 46) with effective regurgitant orifice ≥ 0.30 cm2 and left ventricular (LV) ejection fraction > 60% were examined with right heart catheterisation during rest and exercise and CMRI at rest. End-diastolic pressure volume relationship (EDPVR) was assessed using a single beat method using pulmonary capillary wedge pressure (PCWP) and end-diastolic volume. Patients were divided according to normal PCWP at rest (> 12 mm Hg) and with exercise (> 28 mm Hg). Results: Resting regurgitant volume correlated positively with resting PCWP, (r = 0.42, p = 0.002). However, with exercise no association between PCWP and regurgitant volume was seen (r = 0.09, p = 0.55). At rest left atrial (LA) maximal, minimal and volume index at atrial contraction correlated positively with PCWP (r = 0.60; r = 0.55; r = 0.58, all p < 0.001); in contrast none of these correlated with exercise PCWP (all p > 0.2). EDPVR in patients with high PCWP at rest was shifted towards higher volumes for the same pressures. The opposite was seen for patients with high PCWP during exercise where estimated volumes were smaller for the same pressure than patients with normal exercise PCWP. Conclusion In patients with significant MR the degree of regurgitation and LA dilatation is associated with resting PCWP. However, with exercise this association disappears. Estimation of EDPVR suggests lower LV compliance in patients where PCWP is increased with exercise. Clinical trial registration URL: https://clinicaltrials.gov/ct2/show/NCT02961647?term=HEMI&rank=1. ID: NCT02961647

Background— In severe asymptomatic primary mitral valve regurgitation without risk factors, surgery strategy is controversial. We sought to clarify whether being symptomatic corresponds to the hemodynamic burden and reduced exercise capacity. A better understanding of this may contribute to optimize timing of surgery. Methods and Results— Subjects with asymptomatic (New York Heart Association functional class I, n=29) or symptomatic (New York Heart Association functional class II and III, n=28) significant primary mitral valve regurgitation (effective regurgitant orifice, ≥0.30 cm 2 ; left ventricular ejection fraction, >60%) were included. Right heart catheterization during rest and exercise, echocardiography, magnetic resonance imaging, and peak oxygen consumption test was performed. Symptomatic subjects had significantly higher pulmonary capillary wedge pressure at rest (14±4 versus 11±3 mm Hg; P =0.003) and at maximal exercise (30±6 versus 25±7 mm Hg; P =0.02) and higher mean pulmonary artery pressure (PAP) at rest (22±7 versus 18±4 mm Hg; P =0.005) and maximal exercise (46±8 versus 39±7 mm Hg; P =0.005) than asymptomatic subjects. Among asymptomatic subjects with normal resting value, exercise testing revealed a systolic PAP >60 mm Hg in 34%. Also the reverse response with minimal increase in pulmonary capillary wedge pressure and mean PAP during exercise was seen, especially in asymptomatic subjects. Among symptomatic subjects, we found a significant inverse correlation between resting mean PAP and left ventricular ejection fraction ( r =−0.52; P =0.02) and right ventricular ejection fraction ( r =−0.67; P <0.01). Peak oxygen consumption was equal and normal in both groups and correlated with left ventricular stroke volume but not with pulmonary capillary wedge pressure. Conclusions— Symptoms in patients with severe mitral valve regurgitation relate to congestion (pulmonary capillary wedge pressure and PAP), but not to peak oxygen consumption, which is determined by forward left ventricular stroke volume. Exercise testing reveals a higher mitral valve regurgitation burden in apparently asymptomatic patients. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT02961647.

Using the reservoir-wave approach (RWA) we previously characterized pulmonary vasculature mechanics in a normal canine model. We found reflected backward-traveling waves that decrease pressure and increase flow in the proximal pulmonary artery (PA). These waves decrease right ventricular (RV) afterload and facilitate RV ejection. With pathological alterations to the pulmonary vasculature, these waves may change and impact RV performance. Our objective in this study was to characterize PA wave reflection and the alterations in RV performance in cardiac patients, using the RWA. PA pressure, Doppler-flow velocity, and pulmonary arterial wedge pressure were measured in 11 patients with exertional dyspnea. The RWA was employed to analyze PA pressure and flow; wave intensity analysis characterized PA waves. Wave-related pressure was partitioned into two components: pressures due to forward-traveling and to backward-traveling waves. RV performance was assessed by examining the work done in raising reservoir pressure and that associated with the wave components of systolic PA pressure. Wave-related work, the mostly nonrecoverable energy expended by the RV to eject blood, tended to vary directly with mean PA pressure. Where PA pressures were lower, there were pressure-decreasing/flow-increasing backward waves that aided RV ejection. Where PA pressures were higher, there were pressure-increasing/flow-decreasing backward waves that impeded RV ejection. Pressure-increasing/flow-decreasing backward waves were responsible for systolic notches in the Doppler flow velocity profiles in patients with the highest PA pressure. Pulmonary hypertension is characterized by reflected waves that impede RV ejection and an increase in wave-related work. The RWA may facilitate the development of therapeutic strategies.

Background— Pulmonary hypertension and right ventricular (RV) dysfunction are common in patients with advanced heart failure with preserved ejection fraction (HFpEF), yet their underlying mechanisms remain poorly understood. We sought to examine RV–pulmonary artery (PA) functional reserve responses and RV–PA coupling at rest and during β-adrenergic stimulation in subjects with earlier stage HFpEF. Methods and Results— In a prospective trial, subjects with HFpEF (n=39) and controls (n=18) underwent comprehensive invasive and noninvasive hemodynamic assessment using high fidelity micromanometer catheters, echocardiography, and expired gas analysis at rest and during dobutamine infusion. HFpEF subjects displayed similar RV structure but significantly impaired RV systolic (lower RV d P /d t max /IP and s′) and diastolic function (higher RV τ) coupled with more severe pulmonary vascular disease, manifest by higher PA pressures, higher PA resistance, and lower PA compliance compared with controls. Dobutamine infusion caused greater pulmonary vasodilation in HFpEF compared with controls, with enhanced reductions in PA resistance, greater increase in PA compliance, and a more negative slope in the PA pressure–flow relationship when compared with controls (all P <0.001). RV–PA coupling analysis revealed that dobutamine improved RV ejection in HFpEF subjects through afterload reduction alone, rather than through enhanced contractility, indicating RV systolic reserve dysfunction. Conclusions— Pulmonary hypertension in early stage HFpEF is related to partially reversible pulmonary vasoconstriction coupled with RV systolic and diastolic dysfunction, even in the absence of RV structural remodeling. Pulmonary vascular tone is more favorably responsive to β-adrenergic stimulation in HFpEF than controls, suggesting a potential role for β-agonists in the treatment of patients with HFpEF and pulmonary hypertension. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01418248.

Background— Invasive hemodynamic exercise testing is commonly used in the evaluation of patients with suspected heart failure with preserved ejection fraction (HFpEF) or pulmonary hypertension. Saline loading has been suggested as an alternative provocative maneuver, but the hemodynamic changes induced by the 2 stresses have not been compared. Methods and Results— Twenty-six subjects (aged, 67±10 years; n=14 HFpEF; n=12 control) underwent right heart catheterization at rest, during supine exercise, and with acute saline loading in a prospective study. Exercise and saline each increased cardiac output and pressures in the right atrium, pulmonary artery, and pulmonary capillary wedge positions. Changes in heart rate, blood pressure, rate–pressure product, and cardiac output were greater with exercise compared with saline. In controls subjects, right atrial pressure, pulmonary arterial pressure, and pulmonary capillary wedge pressure increased similarly with saline and exercise, whereas in HFpEF subjects, exercise led to ≈2-fold greater increases in right atrial pressure (10±4 versus 6±3 mm Hg; P =0.02), pulmonary arterial pressure (22±8 versus 11±4 mm Hg; P =0.0001), and pulmonary capillary wedge pressure (18±5 versus 10±4 mm Hg; P <0.0001) compared with saline. Systolic reserve assessed by stroke work and cardiac power output was lower in HFpEF subjects with both exercise and saline. Systemic and pulmonary arterial compliances were enhanced with saline but reduced with exercise. Conclusions— Exercise elicits greater pulmonary capillary wedge pressure elevation compared with saline in HFpEF but not controls, suggesting that hemodynamic stresses beyond passive stiffness and increased venous return explain the development of pulmonary venous hypertension in HFpEF. Exercise testing is more sensitive than saline loading to detect hemodynamic derangements indicative of HFpEF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01418248.