2-Year Outcomes of an Atrial Shunt Device in HFpEF/HFmrEF: Results From REDUCE LAP-HF II.

BACKGROUND: The REDUCE LAP-HF II (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure II) trial found that, compared with a sham procedure, the Corvia Atrial Shunt did not improve outcomes in heart failure with preserved or mildly reduced ejection fraction. However, after 12-month follow-up, "responders" (peak-exercise pulmonary vascular resistance <1.74 WU and absence of a cardiac rhythm management device) were identified. OBJECTIVES: This study sought to determine: 1) the overall efficacy and safety of the atrial shunt vs sham control after 2 years of follow-up; and 2) whether the benefits of atrial shunting are sustained in responders during longer-term follow-up or are offset by adverse effects of the shunt. METHODS: The study analyzed 2-year outcomes in the overall REDUCE LAP-HF II trial, as well as in responder and nonresponder subgroups. The primary endpoint was a hierarchical composite of cardiovascular death or nonfatal ischemic/embolic stroke, total heart failure events, and change in health status. RESULTS: In 621 randomized patients, there was no difference between the shunt (n = 309) and sham (n = 312) groups in the primary endpoint (win ratio: 1.01 [95% CI: 0.82-1.24]) or its individual components at 2 years. Shunt patency at 24 months was 98% in shunt-treated patients. Cardiovascular mortality and nonfatal ischemic stroke were not different between the groups; however, major adverse cardiac events were more common in those patients assigned to the shunt compared with sham (6.9% vs 2.7%; P = 0.018). More patients randomized to the shunt had an increase in right ventricular volume of ≥30% compared with the sham control (39% vs 28%, respectively; P < 0.001), but right ventricular dysfunction was uncommon and not different between the treatment groups. In responders (n = 313), the shunt was superior to sham (win ratio: 1.36 [95% CI: 1.02-1.83]; P = 0.037, with 51% fewer HF events [incidence rate ratio: 0.49 [95% CI: 0.25-0.95]; P = 0.034]). In nonresponders (n = 265), atrial shunting was inferior to sham (win ratio: 0.73 [95% CI: 0.54-0.98]). CONCLUSIONS: At 2 years of follow-up in REDUCE LAP-HF II, there was no difference in efficacy between the atrial shunt and sham groups in the overall trial group. The potential clinical benefit identified in the responder group after 1 and 2 years of follow-up is currently being evaluated in the RESPONDER-HF (Re-Evaluation of the Corvia Atrial Shunt Device in a Precision Medicine Trial to Determine Efficacy in Mildly Reduced or Preserved Ejection Fraction Heart Failure) trial. (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure II [REDUCE LAP-HF II]; NCT03088033).

Atrial Shunt Device Effects on Cardiac Structure and Function in Heart Failure With Preserved Ejection Fraction: The REDUCE LAP-HF II Randomized Clinical Trial.

Importance: Although the results of A Study to Evaluate the Corvia Medical Inc IASD System II to Reduce Elevated Left Atrial Pressure in Patients with Heart Failure (REDUCE LAP-HF II) trial were neutral overall, atrial shunt therapy demonstrated potential efficacy in responders (no latent pulmonary vascular disease and no cardiac rhythm management device). Post hoc analyses were conducted to evaluate the effect of shunt vs sham stratified by responder status. Objective: To evaluate the effect of atrial shunt vs sham control on cardiac structure/function in the overall study and stratified by responder status. Design, Setting, and Participants: This was a sham-controlled randomized clinical trial of an atrial shunt device in heart failure with preserved ejection fraction (HFpEF)/HF with mildly reduced EF (HFmrEF). Trial participants with evaluable echocardiography scans were recruited from 89 international medical centers. Data were analyzed from April 2023 to January 2024. Interventions: Atrial shunt device or sham control. Main Outcome Measures: Changes in echocardiographic measures from baseline to 1, 6, 12, and 24 months after index procedure. Results: The modified intention-to-treat analysis of the REDUCE LAP-HF II trial included 621 randomized patients (median [IQR] age, 72.0 [66.0-77.0] years; 382 female [61.5%]; shunt arm, 309 [49.8%]; sham control arm, 312 [50.2%]). Through 24 months, 212 of 217 patients (98%) in the shunt arm with evaluable echocardiograms had patent shunts. In the overall trial population, the shunt reduced left ventricular (LV) end-diastolic volume (mean difference, -5.65 mL; P <.001), left atrial (LA) minimal volume (mean difference, -2.8 mL; P =.01), and improved LV systolic tissue Doppler velocity (mean difference, 0.69 cm/s; P <.001) and LA emptying fraction (mean difference, 1.88 percentage units; P =.02) compared with sham. Shunt treatment also increased right ventricular (RV; mean difference, 9.58 mL; P <.001) and right atrial (RA; mean difference, 9.71 mL; P <.001) volumes but had no effect on RV systolic function, pulmonary artery pressure, or RA pressure compared with sham. In the shunt arm, responders had smaller increases in RV end-diastolic volume (mean difference, 5.71 mL vs 15.18 mL; interaction P =.01), RV end-systolic volume (mean difference, 1.58 mL vs 7.89 mL; interaction P =.002), and RV/LV ratio (mean difference, 0.07 vs 0.20; interaction P <.001) and larger increases in transmitral A wave velocity (mean difference, 5.08 cm/s vs -1.97 cm/s; interaction P =.02) compared with nonresponders randomized to the shunt, suggesting greater ability to accommodate shunted blood through the pulmonary circulation enabling LA unloading. Conclusions and Relevance: In this post hoc analysis of the REDUCE LAP-HF II trial, over 2 years of follow-up, atrial shunting led to reverse remodeling of left-sided chambers and increases in volume of right-sided chambers consistent with the shunt flow but no change in RV systolic function compared with sham. Changes in cardiac structure/function were more favorable in responders compared with nonresponders treated with the shunt, supporting the previously identified responder group hypothesis and mechanism, although further evaluation with longer follow-up is needed. Trial Registration: ClinicalTrials.gov Identifier: NCT03088033.

Obesity in heart failure with preserved ejection fraction: Insights from the REDUCE LAP-HF II trial.

AIMS: Obesity is causally related to the development of heart failure with preserved ejection fraction (HFpEF) but complicates the diagnosis and treatment of this disorder. We aimed to determine the relationship between severity of obesity and clinical, echocardiographic and haemodynamic parameters in a large cohort of patients with documented HFpEF. METHODS AND RESULTS: The REDUCE LAP-HF II trial randomized 626 patients with ejection fraction ≥40% and exercise pulmonary capillary wedge pressure (PCWP) ≥25 mmHg to atrial shunt or sham procedure. We tested for associations between body mass index (BMI), clinical characteristics, cardiac structural and functional abnormalities, physical limitations, quality of life and outcomes with atrial shunt therapy. Overall, 60.9% of patients had BMI ≥30 kg/m2 . As the severity of obesity increased, symptoms (Kansas City Cardiomyopathy Questionnaire score) and 6-min walk distance worsened. More severe obesity was associated with lower natriuretic peptide levels despite more cardiac remodelling, higher cardiac filling pressures, and higher cardiac output. Lower cut points for E/e' were needed to identify elevated PCWP in more obese patients. Strain measurements in all four chambers were maintained as BMI increased. Pulmonary vascular resistance at rest and exercise decreased with higher BMI. Obesity was associated with more first and recurrent heart failure events. However, there was no significant interaction between obesity and treatment effects of the atrial shunt. CONCLUSIONS: Increasing severity of obesity was associated with greater cardiac remodelling, higher right and left ventricular filling pressures, higher cardiac output and increased subsequent heart failure events. Despite significant obesity, many HFpEF patients have preserved right heart and pulmonary vascular function and thus, may be appropriate candidates for atrial shunt therapy.

Atrial Fibrillation Burden and Atrial Shunt Therapy in Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Atrial fibrillation (AF) is a common comorbidity in patients with heart failure with preserved ejection fraction (HFpEF) and in heart failure with mildly reduced ejection fraction (HFmrEF). OBJECTIVES: This study sought to describe AF burden and its clinical impact among individuals with HFpEF and HFmrEF who participated in a randomized clinical trial of atrial shunt therapy (REDUCE LAP-HF II [A Study to Evaluate the Corvia Medical, Inc IASD System II to Reduce Elevated Left Atrial Pressure in Patients with Heart Failure]) and to evaluate the effect of atrial shunt therapy on AF burden. METHODS: Study investigators characterized AF burden among patients in the REDUCE LAP-HF II trial by using ambulatory cardiac patch monitoring at baseline (median patch wear time, 6 days) and over a 12-month follow-up (median patch wear time, 125 days). The investigators determined the association of baseline AF burden with long-term clinical events and examined the effect of atrial shunt therapy on AF burden over time. RESULTS: Among 367 patients with cardiac monitoring data at baseline and follow-up, 194 (53%) had a history of AF or atrial flutter (AFL), and median baseline AF burden was 0.012% (IQR: 0%-1.3%). After multivariable adjustment, baseline AF burden ≥0.012% was significantly associated with heart failure (HF) events (HR: 2.00; 95% CI: 1.17-3.44; P = 0.01) both with and without a history of AF or AFL (P for interaction = 0.68). Adjustment for left atrial reservoir strain attenuated the baseline AF burden-HF event association (HR: 1.71; 95% CI: 0.93-3.14; P = 0.08). Of the 367 patients, 141 (38%) had patch-detected AF during follow-up without a history of AF or AFL. Atrial shunt therapy did not change AF incidence or burden during follow-up. CONCLUSIONS: In HFpEF and HFmrEF, nearly 40% of patients have subclinical AF by 1 year. Baseline AF burden, even at low levels, is associated with HF events. Atrial shunt therapy does not affect AF incidence or burden. (A Study to Evaluate the Corvia Medical, Inc IASD System II to Reduce Elevated Left Atrial Pressure in Patients with Heart Failure [REDUCE LAP-HF II]; NCT03088033).

Exercise-Induced Left Atrial Hypertension in Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Many patients with heart failure and preserved ejection fraction have no overt volume overload and normal resting left atrial (LA) pressure. OBJECTIVES: This study sought to characterize patients with normal resting LA pressure (pulmonary capillary wedge pressure [PCWP] <15 mm Hg) but exercise-induced left atrial hypertension (EILAH). METHODS: The REDUCE LAP-HF II (A Study to Evaluate the Corvia Medical, Inc. IASD System II to Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) trial randomized 626 patients with ejection fraction ≥40% and exercise PCWP ≥25 mm Hg to atrial shunt or sham procedure. The primary trial outcome, a hierarchical composite of death, heart failure hospitalization, intensification of diuretics, and change in health status was compared between patients with EILAH and those with heart failure and resting left atrial hypertension (RELAH). RESULTS: Patients with EILAH (29%) had similar symptom severity, but lower natriuretic peptide levels, higher 6-minute walk distance, less atrial fibrillation, lower left ventricular mass, smaller LA volumes, lower E/e', and better LA strain. PCWP was lower at rest, but had a larger increase with exercise in EILAH. Neither group as a whole had a significant effect from shunt therapy vs sham. Patients with EILAH were more likely to have characteristics associated with atrial shunt responsiveness (peak exercise pulmonary vascular resistance <1.74 WU) and no pacemaker (63% vs 46%; P < 0.001). The win ratio for the primary outcome was 1.56 (P = 0.08) in patients with EILAH and 1.51 (P = 0.04) in those with RELAH when responder characteristics were present. CONCLUSIONS: Patients with EILAH had similar symptom severity but less advanced myocardial and pulmonary vascular disease. This important subgroup may be difficult to diagnose without invasive exercise hemodynamics, but it has characteristics associated with favorable response to atrial shunt therapy. (A Study to Evaluate the Corvia Medical, Inc. IASD System II to Reduce Elevated Left Atrial Pressure in Patients With Heart Failure [REDUCE LAP-HF TRIAL II]; NCT03088033).

Left atrial enlargement is associated with pulmonary vascular disease in heart failure with preserved ejection fraction.

AIMS: Elevated left atrial (LA) pressure is a pathophysiologic hallmark of heart failure with preserved ejection fraction (HFpEF). Chronically elevated LA pressure leads to LA enlargement, which may impair LA function and increase pulmonary pressures. We sought to evaluate the relationship between LA volume and pulmonary arterial haemodynamics in patients with HFpEF. METHODS AND RESULTS: Data from 85 patients (aged 69 ± 8 years) who underwent exercise right heart catheterization and echocardiography were retrospectively analysed. All had symptoms of heart failure, left ventricular ejection fraction ≥50% and haemodynamic features of HFpEF. Patients were divided into LA volume index-based tertiles (≤34 ml/m2 , >34 to ≤45 ml/m2 , >45 ml/m2 ). A subgroup analysis was performed in patients with recorded LA global reservoir strain (n = 60), with reduced strain defined as ≤24%. Age, sex, body surface area and left ventricular ejection fraction were similar between volume groups. LA volume was associated with blunted increases in cardiac output with exercise (padjusted <0.001), higher resting mean pulmonary artery pressure (padjusted  = 0.003), with similar wedge pressure (padjusted  = 1). Pulmonary vascular resistance (PVR) increased with increasing LA volume (padjusted <0.001). Larger LA volumes featured reduced LA strain (padjusted <0.001), with reduced strain associated with reduced PVR-compliance time (0.34 [0.28-0.40] vs. 0.38 [0.33-0.43], p = 0.03). CONCLUSION: Increasing LA volume may be associated with more advanced pulmonary vascular disease in HFpEF, featuring higher PVR and pulmonary pressures. Reduced LA function, worse at increasing LA volumes, is associated with a disrupted PVR-compliance relationship, further augmenting impaired pulmonary haemodynamics.

Long-term follow-up of a patient undergoing interatrial shunt device implantation for treatment of heart failure with a preserved ejection fraction.

We herein present a case study of a patient with heart failure with a preserved ejection fraction and severe symptoms who underwent interatrial shunt device implantation and follow-up at a tertiary care heart failure clinic. The interatrial shunt device implantation was successful. No adverse events occurred, and the device prevented hospitalization for heart failure during long-term follow-up.

Latent Pulmonary Vascular Disease May Alter the Response to Therapeutic Atrial Shunt Device in Heart Failure.

BACKGROUND: In REDUCE LAP-HF II (A Study to Evaluate the Corvia Medical, Inc IASD System II to Reduce Elevated Left Atrial Pressure in Patients With Heart Failure), implantation of an atrial shunt device did not provide overall clinical benefit for patients with heart failure with preserved or mildly reduced ejection fraction. However, prespecified analyses identified differences in response in subgroups defined by pulmonary artery systolic pressure during submaximal exercise, right atrial volume, and sex. Shunt implantation reduces left atrial pressures but increases pulmonary blood flow, which may be poorly tolerated in patients with pulmonary vascular disease (PVD). On the basis of these results, we hypothesized that patients with latent PVD, defined as elevated pulmonary vascular resistance during exercise, might be harmed by shunt implantation, and conversely that patients without PVD might benefit. METHODS: REDUCE LAP-HF II enrolled 626 patients with heart failure, ejection fraction ≥40%, exercise pulmonary capillary wedge pressure ≥25 mm Hg, and resting pulmonary vascular resistance <3.5 Wood units who were randomized 1:1 to atrial shunt device or sham control. The primary outcome-a hierarchical composite of cardiovascular death, nonfatal ischemic stroke, recurrent HF events, and change in health status-was analyzed using the win ratio. Latent PVD was defined as pulmonary vascular resistance ≥1.74 Wood units (highest tertile) at peak exercise, measured before randomization. RESULTS: Compared with patients without PVD (n=382), those with latent PVD (n=188) were older, had more atrial fibrillation and right heart dysfunction, and were more likely to have elevated left atrial pressure at rest. Shunt treatment was associated with worse outcomes in patients with PVD (win ratio, 0.60 [95% CI, 0.42, 0.86]; P=0.005) and signal of clinical benefit in patients without PVD (win ratio, 1.31 [95% CI, 1.02, 1.68]; P=0.038). Patients with larger right atrial volumes and men had worse outcomes with the device and both groups were more likely to have pacemakers, heart failure with mildly reduced ejection fraction, and increased left atrial volume. For patients without latent PVD or pacemaker (n=313; 50% of randomized patients), shunt treatment resulted in more robust signal of clinical benefit (win ratio, 1.51 [95% CI, 1.14, 2.00]; P=0.004). CONCLUSIONS: In patients with heart failure with preserved or mildly reduced ejection fraction, the presence of latent PVD uncovered by invasive hemodynamic exercise testing identifies patients who may worsen with atrial shunt therapy, whereas those without latent PVD may benefit.

Update on Atrial Shunt Therapy for Treatment of Heart Failure.

Heart failure with preserved ejection fraction is associated with elevated left atrial pressure during exercise. Sodium-glucose cotransporter-2 inhibitors have demonstrated the evidence of benefit in heart failure with preserved ejection fraction, but even with this treatment, heart failure hospitalizations remain high, and improvements in quality of life scores are modest. Thus, there is growing interest in nonpharmacological methods of limiting the rise in left atrial pressure during exertion. Creation of an interatrial shunt (IAS) may unload the left heart during exercise. Multiple implant or nonimplant IAS procedures are under investigation. Implantation of the most studied device results in 3 to 5 mm Hg decreases in pulmonary capillary wedge pressure during exercise, no increase in incidence of stroke, stable increases in Qp/Qs (1.2-1.3), and mild right heart enlargement without change in function out to at least a year after treatment. The findings from the first large randomized controlled trial of an atrial shunt have recently been published. For the population as a whole, implantation of the atrial shunt device appeared to be safe but did not provide clinical benefit. However, prespecified and post-hoc analyses have demonstrated that men, patients with larger right atrial volumes, and those with pulmonary artery systolic pressure >70 mm Hg at 20 W exercise had worse outcomes with IAS therapy, whereas those with peak exercise pulmonary vascular resistance <1.74 Wood units and absence of a pacemaker represented a potential responder group. Here, we summarize the results of the published data and the current IAS therapies under investigation. We also highlight unanswered questions in this field of inquiry.

Determinants and consequences of heart rate and stroke volume response to exercise in patients with heart failure and preserved ejection fraction.

AIMS: A hallmark of heart failure with preserved ejection fraction (HFpEF) is impaired exercise capacity of varying severity. The main determinant of exercise capacity is cardiac output (CO), however little information is available about the relation between the constituents of CO - heart rate and stroke volume - and exercise capacity in HFpEF. We sought to determine if a heterogeneity in heart rate and stroke volume response to exercise exists in patients with HFpEF and describe possible clinical phenotypes associated with differences in these responses. METHODS AND RESULTS: Data from two prospective trials of HFpEF (n = 108) and a study of healthy participants (n = 42) with invasive haemodynamic measurements during exercise were utilized. Differences in central haemodynamic responses were analysed with regression models. Chronotropic incompetence was present in 39-56% of patients with HFpEF and 3-56% of healthy participants depending on the definition used, but some (n = 47, 44%) had an increase in heart rate similar to that of healthy controls. Patients with HFpEF had a smaller increase in their stroke volume index (SVI) (HFpEF: +4 ± 10 mL/m2 , healthy participants: +24 ± 12 mL/m2 , P < 0.0001), indeed, SVI fell in 28% of patients at peak exercise. Higher body mass index and lower SVI at rest were associated with smaller increases in heart rate during exercise, whereas higher resting heart rate, and angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker use were associated with a greater increase in SVI in patients with HFpEF. CONCLUSION: The haemodynamic response to exercise was very heterogeneous among patients with HFpEF, with chronotropic incompetence observed in up to 56%, and 28% had impaired increase in SVI. This suggests that haemodynamic exercise testing may be useful to identify which HFpEF patients may benefit from interventions targeting stroke volume and chronotropic response.

Impact of Interatrial Shunts on Invasive Hemodynamics and Exercise Tolerance in Patients With Heart Failure.

Approximately 50% of patients with heart failure have preserved ejection fraction. Although a wide variety of conditions cause or contribute to heart failure with preserved ejection fraction, elevated left ventricular filling pressures, particularly during exercise, are common to all causes. Acute elevation in left-sided filling pressures promotes lung congestion and symptoms of dyspnea, while chronic elevations often lead to pulmonary vascular remodeling, right heart failure, and increased risk of mortality. Pharmacologic therapies, including neurohormonal modulation and drugs that modify the nitric oxide/cyclic GMP-protein kinase G pathway have thus far been limited in reducing symptoms or improving outcomes in patients with heart failure with preserved ejection fraction. Hence, alternative means of reducing the detrimental rise in left-sided heart pressures are being explored. One proposed method of achieving this is to create an interatrial shunt, thus unloading the left heart at rest and during exercise. Currently available studies have shown 3- to 5-mm Hg decreases of pulmonary capillary wedge pressure during exercise despite increased workload. The mechanisms underlying the hemodynamic changes are just starting to be understood. In this review we summarize results of recent studies aimed at elucidating the potential mechanisms of improved hemodynamics during exercise tolerance following interatrial shunt implantation and the current interatrial shunt devices under investigation.

Transcatheter InterAtrial Shunt Device for the treatment of heart failure: Rationale and design of the pivotal randomized trial to REDUCE Elevated Left Atrial Pressure in Patients with Heart Failure II (REDUCE LAP-HF II).

BACKGROUND: A randomized, sham-controlled trial in patients with heart failure (HF) and left ventricular ejection fraction (LVEF) ≥40% demonstrated reductions in pulmonary capillary wedge pressure (PCWP) with a novel transcatheter InterAtrial Shunt Device (IASD). Whether this hemodynamic effect will translate to an improvement in cardiovascular outcomes and symptoms requires additional study. STUDY DESIGN AND OBJECTIVES: REDUCE Elevated Left Atrial Pressure in Patients with Heart Failure II (REDUCE LAP HF-II) is a multicenter, prospective, randomized, sham-controlled, blinded trial designed to evaluate the clinical efficacy of the IASD in symptomatic HF and elevated left atrial pressures. Up to 608 HF patients age ≥ 40 years with LVEF ≥40%, PCWP ≥25 mm Hg during supine ergometer exercise, and PCWP ≥5 mm Hg higher than right atrial pressure will be randomized 1:1 to the IASD versus sham control. Key exclusion criteria include hemodynamically significant valvular disease, evidence of pulmonary arterial hypertension, and right heart dysfunction. The primary endpoint is a hierarchical composite, analyzed by the Finkelstein-Schoenfeld methodology, that includes (1) cardiovascular mortality or first nonfatal ischemic stroke through 12 months; (2) total (first plus recurrent) HF hospitalizations or healthcare facility visits for intravenous diuretics up to 24 months, analyzed when the last randomized patient completes 12 months of follow-up; and (3) change in Kansas City Cardiomyopathy Questionnaire overall summary score from baseline to 12 months. Follow-up echocardiography will be performed at 6, 12, and 24 months to evaluate shunt flow and cardiac chamber size/function. Patients will be followed for a total of 5 years after the index procedure. CONCLUSIONS: REDUCE LAP-HF II is designed to evaluate the clinical efficacy of the IASD device in patients with symptomatic HF with elevated left atrial pressure and LVEF ≥40%.

Effects of Interatrial Shunt on Pulmonary Vascular Function in Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Implantation of an interatrial shunt device (IASD) in patients with heart failure (HF) reduces left atrial hypertension by shunting oxygenated blood to the right heart and lungs. The attendant increases in pulmonary blood flow (Qp) and oxygen content may alter pulmonary vascular function, while left-to-right shunting might compromise systemic perfusion. OBJECTIVES: The authors hypothesized that IASD would improve indexes of pulmonary artery (PA) function at rest and during exercise in HF patients without reducing systemic blood flow (Qs). METHODS: This is a pooled analysis from 2 trials assessing the effects of the IASD on resting and exercise hemodynamics in HF patients (n = 79) with EF ≥40% with baseline and repeated hemodynamic evaluation between 1 and 6 months. Patients with pulmonary vascular resistance (PVR) >4 WU or right ventricular dysfunction were excluded. RESULTS: Qp and PA oxygen content increased by 27% and 7% following IASD. These changes were associated with salutary effects on pulmonary vascular function (17% reduction in PVR, 12% reduction in PA elastance [pulmonary Ea], and 24% increase in PA compliance). Qp increased during exercise to a greater extent following IASD compared with baseline, which was associated with reductions in exercise PVR and pulmonary Ea. Patients with increases in PA compliance following IASD experienced greater improvements in supine exercise duration. There was no reduction in Qs following IASD at rest or during exercise. CONCLUSIONS: Implantation of an IASD improves pulmonary vascular function at rest and during exercise in selected patients with HF and EF ≥40%, without compromising systemic perfusion. Further study is warranted to identify underlying mechanisms and long-term pulmonary hemodynamic effects of IASD. (REDUCE LAP-HF Trial [REDUCE LAP-HF]; NCT01913613; and REDUCE LAP-HF Randomized Trial I [REDUCE LAP-HF I]; NCT02600234).

Assessment of Predictors of Left Atrial Volume Response to a Transcatheter InterAtrial Shunt Device (from the REDUCE LAP-HF Trial).

In patients with heart failure and preserved or mildly reduced ejection fractions (EF ≥40%), implantation of an interatrial shunt device (IASD) resulted in heterogenous changes of the left atrial (LA) volume. Baseline characteristics that correlate with a favorable decrease in LA volume are unknown. We hypothesized that a larger ratio of left to right atrial volume at baseline would correlate strongly with LA volume decongestion following IASD implantation. Reduce Elevated LA Pressure in Patients With Heart Failure was a multicenter study of the safety and feasibility of IASD implantation. Sixty-four patients with EF ≥40% underwent device implantation along with baseline conventional echocardiograms, speckle tracking echocardiography, and resting and exercise hemodynamics. Higher LA compliance (-4.2%, p = 0.048) and right atrial reservoir strain (-0.8%, p = 0.005) were independently associated with a percent decrease in the systolic LA volume index from baseline to 6-months. In conclusion, greater LA volume reduction following IASD implantation is associated with higher baseline compliance of the left atrium and higher reservoir strain of the right atrium.

Central and Peripheral Determinants of Exercise Capacity in Heart Failure Patients With Preserved Ejection Fraction.

OBJECTIVES: This study sought to discern which central (e.g., heart rate, stroke volume [SV], filling pressure) and peripheral factors (e.g., oxygen use by skeletal muscle, body mass index [BMI]) during exercise were most strongly associated with the presence of heart failure and preserved ejection fraction (HFpEF) as compared with healthy control subjects exercising at the same workload. BACKGROUND: The underlying mechanisms limiting exercise capacity in patients with HFpEF are not fully understood. METHODS: In patients with HFpEF (n = 108), the hemodynamic response at peak exercise was measured using right-sided heart catheterization and was compared with that in healthy control subjects (n = 42) at matched workloads to reveal hemodynamic differences that were not attributable to the workload performed. The patients studied were prospectively included in the REDUCE-LAP HF (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) trials and HemReX (Effect of Age on the Hemodynamic Response During Rest and Exercise in Healthy Humans) study. Univariable and multivariable logistic regression models were used to analyze variables associated with HFpEF versus control subjects. RESULTS: Compared with healthy control subjects, pulmonary capillary wedge pressure (PCWP) and SV were the only independent hemodynamic variables that were associated with HFpEF, a finding explaining 66% (p < 0.0001) of the difference between the groups. When relevant baseline characteristics were added to the base model, only BMI emerged as an additional independent variable, in total explaining of 90% of the differences between groups (p < 0.0001): PCWP (47%), BMI (31%), and SV (12%). CONCLUSIONS: The study identified 3 key variables (PCWP, BMI, and SV) that independently correlate with the presence of patients with HFpEF compared with healthy control subjects exercising at the same workload. Therapies that decrease left-sided heart filling pressures could improve exercise capacity and possibly prognosis.

Impact of Baseline Hemodynamics on the Effects of a Transcatheter Interatrial Shunt Device in Heart Failure With Preserved Ejection Fraction.

Background Interatrial shunt device (IASD) effects have been described in patients with heart failure and ejection fractions (EFs) ≥40%. However, baseline characteristics that correlate with greatest hemodynamic effects are unknown. On the basis of fundamental principles, we hypothesized that larger pressure gradients between left and right atria would yield greater shunt flow and greater hemodynamic effects. Methods and Results REDUCE LAP-HF (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) was a multicenter study that investigated IASD safety and performance. Sixty-four patients with EF ≥40% underwent device implantation followed by hemodynamic assessments at rest and exercise, including pulmonary capillary wedge pressure (PCWP, surrogate for left atrial pressure) and central venous pressure (CVP). At 6 months, IASD resulted in an average pulmonary-to-systemic blood flow ratio of 1.27 and increased exercise tolerance. The PCWP-CVP gradient (ie, the driving pressure for shunt flow) decreased at peak exercise from 16.8±6.9 to 11.4±5.5 mm Hg, because of increased CVP (17.5±5.4 to 20.3±7.9 mm Hg; P=0.04) and decreased PCWP (34.1±7.6 to 31.6±8.0 mm Hg; P=0.025). Baseline PCWP-CVP gradient during exercise correlated with changes of both PCWP-CVP and PCWP: Δ(PCWP-CVP)=10.0-0.89·(PCWP-CVP)baseline ( r2=0.56) and ΔPCWP=7.54-0.60·(PCWP-CVP)baseline ( P=0.001). Hemodynamics of patients with EF ≥50% and those with EF <50% responded similarly to IASD. Conclusions In heart failure patients with EF ≥40%, IASD significantly reduced PCWP and PCWP-CVP at peak exercise. Patients with higher baseline PCWP-CVP gradient had greater reductions in both parameters at follow-up. Results were sustained through 12 months and were independent of whether EF was ≥50% or between 40% and 49%. Additional studies will help further define the baseline hemodynamic predictors of exercise, hemodynamic, and clinical efficacy of the IASD. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT01913613.

Resting and exercise haemodynamics in relation to six-minute walk test in patients with heart failure and preserved ejection fraction.

AIMS: Patients with heart failure and preserved ejection fraction (HFpEF) are characterized by functional impairment and an abnormal haemodynamic response to exercise. The six-minute walk test (6MWT) serves as a standardized test for functional capacity quantification in heart failure patients, and is associated with cardiovascular outcomes. However, as the association between 6MWT and haemodynamic parameters during rest and exercise in HFpEF patients is unknown, we sought to elucidate this relationship. METHODS AND RESULTS: Overall, 64 patients enrolled in the REDUCE LAP-HF trial completed a 6MWT at baseline. Univariate and multivariable linear regression models were used to assess the associations between 6MWT and measured or derived haemodynamic variables at baseline, during light/moderate exercise (20 W), and at peak supine exercise. The average 6MWT distance was 318 ± 106 m. At rest, in a multivariable model, only pulmonary capillary wedge pressure (PCWP) was significantly associated with 6MWT [coefficient: -5.4, 95% confidence interval (CI) -10.4, -0.5, P = 0.033]. During light/moderate exercise, mean pulmonary artery pressure was associated with 6MWT in a multivariable model (coefficient: -3.5, 95% CI -6.8, -0.3, P = 0.033). During peak exercise, central venous pressure, cardiac index (CI), and PCWP/CI correlated with 6MWT; however, workload corrected PCWP was the only variable independently associated with 6MWT (coefficient: -0.8, 95% CI -1.3, -0.4, P < 0.001). The variance in 6MWT was modestly explained by measured or derived haemodynamic variables at rest or at any stage of exercise (r2 = 7-17%). CONCLUSION: Workload corrected PCWP correlated best with 6MWT performance in HFpEF patients. Baseline haemodynamic variables were modestly correlated with 6MWT, suggesting that 6MWT performance in HFpEF patients may be significantly influenced by extra-cardiac factors.

Impact of atrial fibrillation on rest and exercise haemodynamics in heart failure with mid-range and preserved ejection fraction.

AIMS: Heart failure with preserved (HFpEF) and mid-range ejection fraction (HFmrEF) are becoming the most prevalent forms of heart failure. Patients with HFpEF/HFmrEF in atrial fibrillation (AF) have poorer survival and quality of life, but the mechanism underpinning this is unknown. We sought to investigate the influence of AF on the haemodynamic profile of HFpEF/HFmrEF patients at rest and during exercise. METHODS AND RESULTS: We invasively measured central haemodynamics at rest and during symptom-limited supine bicycle exercise in HFpEF/HFmrEF patients, 35 in sinus rhythm and 20 in AF with matched left ventricular ejection fraction. At rest, AF patients had significantly increased pulmonary capillary wedge pressure, lower cardiac index and reduced left ventricular stroke work index, despite similar resting heart rate. Under resting conditions, calculated oxygen consumption and systemic arteriovenous oxygen gradient were not different between the two groups. During supine cycling at similar levels of workload, AF patients exhibited a reduced capacity to increase their oxygen consumption and this was accompanied by a persistently impaired cardiac index and left ventricular stroke work index. CONCLUSIONS: The adverse interaction of AF and HFpEF/HFmrEF may be accounted for by an adverse impact on left ventricular systolic function and peripheral oxygen kinetics.