Nitrates in Heart Failure with Preserved Ejection Fraction

Cardiorespiratory fitness and risk of heart failure with preserved ejection fraction

AIMS

Preventive strategies for heart failure with preserved ejection fraction (HFpEF) include pharmacotherapies and lifestyle modifications. However, the association between cardiorespiratory fitness (CRF) assessed objectively by a standardized exercise treadmill test (ETT) and the risk of HFpEF has not been evaluated. Thus, we evaluated the association between CRF and HFpEF incidence.

METHODS AND RESULTS

We assessed CRF in US Veterans (624 551 men; mean age 61.2 ± 9.7 years and 43 179 women; mean age 55.0 ± 8.9 years) by a standardized ETT performed between 1999 and 2020 across US Veterans Affairs Medical Centers. All had no evidence of heart failure or myocardial infarction prior to completion of the ETT. We assigned participants to one of five age- and gender-specific CRF categories (quintiles) based on peak metabolic equivalents (METs) achieved during the ETT and four categories based on CRF changes in those with two ETT evaluations (n = 139 434) ≥1.0 year apart. During a median follow-up of 10.1 years (interquartile range 6.0-14.3 years), providing 6 879 229 person-years, there were 16 493 HFpEF events with an average annual rate of 2.4 events per 1000 person-years. The adjusted risk of HFpEF decreased across CRF categories as CRF increased, independent of comorbidities. For fit individuals (≥10.5 METs) the hazard ratio (HR) was 0.48 (95% confidence interval [CI] 0.46-0.51) compared with least fit (≤4.9 METs; referent). Being unfit carried the highest risk (HR 2.88, 95% CI 2.67-3.11) of any other comorbidity. The risk of unfit individuals who became fit was 37% lower (HR 0.63, 95% CI 0.57-0.71), compared to those who remained unfit.

CONCLUSIONS

Higher CRF levels are independently associated with lower HFpEF in a dose-response manner. Changes in CRF reflected proportional changes in HFpEF risk, suggesting that the HFpEF risk was modulated by CRF.

Pulmonary Capillary Wedge Pressure Patterns During Exercise Predict Exercise Capacity and Incident Heart Failure

BACKGROUND

Single measurements of left ventricular filling pressure at rest lack sensitivity for identifying heart failure with preserved ejection fraction (HFpEF) in patients with dyspnea on exertion. We hypothesized that exercise hemodynamic measurements (ie, changes in pulmonary capillary wedge pressure [PCWP] indexed to cardiac output [CO]) may more sensitively differentiate HFpEF and non-HFpEF disease states, reflect aerobic capacity, and forecast heart failure outcomes in individuals with normal PCWP at rest.

METHODS AND RESULTS

We studied 175 patients referred for cardiopulmonary exercise testing with hemodynamic monitoring: controls (n=33), HFpEF with resting PCWP≥15 mm Hg (n=32), and patients with dyspnea on exertion with normal resting PCWP and left ventricular ejection fraction (DOE-nlrW; n=110). Across 1835 paired PCWP-CO measurements throughout exercise, we used regression techniques to define normative bounds of "PCWP/CO slope" in controls and tested the association of PCWP/CO slope with exercise capacity and composite cardiac outcomes (defined as cardiac death, incident resting PCWP elevation, or heart failure hospitalization) in the DOE-nlrW group. Relative to controls (PCWP/CO slope, 1.2±0.4 mm Hg/L/min), patients with HFpEF had a PCWP/CO slope of 3.4±1.9 mm Hg/L/min. We used a threshold (2 SD above the mean in controls) of 2 mm Hg/L/min to define abnormal. PCWP/CO slope >2 in DOE-nlrW patients was common (n=45/110) and was associated with reduced peak Vo₂ (P<0.001) and adverse cardiac outcomes after adjustment for age, sex, and body mass index (hazard ratio, 3.47; P=0.03) at a median 5.3-year follow-up.

CONCLUSIONS

Elevated PCWP/CO slope during exercise (>2 mm Hg/L/min) is common in DOE-nlrW and predicts exercise capacity and heart failure outcomes. These findings suggest that current definitions of HFpEF based on single measures during rest are insufficient and that assessment of exercise PCWP/CO slope may refine early HFpEF diagnosis.

Isosorbide Dinitrate, With or Without Hydralazine, Does Not Reduce Wave Reflections, Left Ventricular Hypertrophy, or Myocardial Fibrosis in Patients With Heart Failure With Preserved Ejection Fraction

Background

Wave reflections, which are increased in patients with heart failure with preserved ejection fraction, impair diastolic function and promote pathologic myocardial remodeling. Organic nitrates reduce wave reflections acutely, but whether this is sustained chronically or affected by hydralazine coadministration is unknown.

Methods and Results

We randomized 44 patients with heart failure with preserved ejection fraction in a double‐blinded fashion to isosorbide dinitrate (ISDN; n=13), ISDN+hydralazine (ISDN+hydral; n=15), or placebo (n=16) for 6 months. The primary end point was the change in reflection magnitude (RM; assessed with arterial tonometry and Doppler echocardiography). Secondary end points included change in left ventricular mass and fibrosis, measured with cardiac magnetic resonance imaging, and the 6‐minute walk distance. ISDN reduced aortic characteristic impedance (mean baseline=0.15 [95% CI, 0.14–0.17], 3 months=0.11 [95% CI, 0.10–0.13], 6 months=0.10 [95% CI, 0.08–0.12] mm Hg/mL per second; P=0.003) and forward wave amplitude (P_f, mean baseline=54.8 [95% CI, 47.6–62.0], 3 months=42.2 [95% CI, 33.2–51.3]; 6 months=37.0 [95% CI, 27.2–46.8] mm Hg, P=0.04), but had no effect on RM (P=0.64), left ventricular mass (P=0.33), or fibrosis (P=0.63). ISDN+hydral increased RM (mean baseline=0.39 [95% CI, 0.35–0.43]; 3 months=0.31 [95% CI, 0.25–0.36]; 6 months=0.44 [95% CI, 0.37–0.51], P=0.03), reduced 6‐minute walk distance (mean baseline=343.3 [95% CI, 319.2–367.4]; 6 months=277.0 [95% CI, 242.7–311.4] meters, P=0.022), and increased native myocardial T1 (mean baseline=1016.2 [95% CI, 1002.7–1029.7]; 6 months=1054.5 [95% CI, 1036.5–1072.3], P=0.021). A high proportion of patients experienced adverse events with active therapy (ISDN=61.5%, ISDN+hydral=60.0%; placebo=12.5%; P=0.007).

Conclusions

ISDN, with or without hydralazine, does not exert beneficial effects on RM, left ventricular remodeling, or submaximal exercise and is poorly tolerated. ISDN+hydral appears to have deleterious effects on RM, myocardial remodeling, and submaximal exercise. Our findings do not support the routine use of these vasodilators in patients with heart failure with preserved ejection fraction.

Clinical Trial Registration

URL: www.clinicaltrials.gov. Unique identifier: NCT01516346.