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Heart failure with preserved ejection fraction (HFpEF) is a condition with increasing incidence, leading to a health care problem of epidemic proportions for which no curative treatments exist. Consequently, an urge exists to better understand the pathophysiology of HFpEF. Accumulating evidence suggests a key pathophysiological role for coronary microvascular dysfunction (MVD), with an underlying mechanism of low-grade pro-inflammatory state caused by systemic comorbidities.
Study Design | HFpEF Population | Control Population | Method (Measurement) | Stimulus | Microvascular Function Assessed | Outcome (SD/IQR) |
---|---|---|---|---|---|---|
Skin-finger | ||||||
Prospective [22] | n = 321 | Controls without HF, matched for age, sex, HT, and DM (n = 173) | Peripheral arterial tonometry (endoPAT): (RHI) | Ischemia | Hyperaemia | Log RHI: 0.53 ± 0.20 vs. 0.64 ± 0.20, p < 0.001 |
Prospective [10] | n = 202 | No controls | endoPAT (RHI) | Ischemia | Hyperaemia | Log RHI: no absolute values reported. Correlation with CFR of R 0.21, p = 0.004 |
Retrospective [23] | n = 159 | No controls | endoPAT (RHI) | Ischemia | Hyperaemia | Log RHI: 0.50 ± 0.09. Event free 0.52 ± 0.09 vs. Events 0.46 ± 0.08, p < 0.001 |
Prospective (cross-sectional) [24] | n = 62 | Controls matched for age, sex, HT, DM, dyslipidaemia and CAD (n = 64) | endoPAT (RHI) | Ischemia | Hyperaemia | RHI: 2.01 [1.64–2.42] vs. 1.70 [1.55–1.88], p < 0.001 |
Prospective [25] | n = 42 | HFrEF (n = 46) | endoPAT (RHI) | Ischemia | Hyperaemia | RHI: 1.77 [1.67–2.16] vs. 1.53 [1.42–1.94], p = 0.014. |
Prospective [26] | n = 26 | Healthy controls, matched for age and sex (n = 26) | endoPAT (RHI) | Ischemia | Hyperaemia | RHI interpretation from boxplots: 1.9 [1.6–2.9] vs. 1.8 [2.0–3.3], p = 0.036. No effect of exercise |
Prospective [27] | n = 21 | HT controls without HF (n = 19) Healthy controls (n = 10) |
endoPAT (RHI) | Ischemia | Hyperaemia | Log RHI: 0.85 ± 0.42 vs. 0.92 ± 0.38 vs. 1.33 ± 0.34, p = n.s. between HFpEF and HT controls |
Skin-arm | ||||||
Prospective [28] | n = 45 | HT controls, matched for age, sex and diabetic status (n = 45) | Laser Doppler flowmetry (LDF), power spectral density (PSD) of the LDF signal | None, ischemia | Vasomotion, hyperaemia | LDF PSD: lower in HFpEF, no absolute numbers reported, p < 0.05. Peak blood flow (PU): 135 [104–206] vs. 177 [139–216], p = 0.03 |
Prospective [11] | HFpEF with CAD n = 12 | HFrEF with CAD (n = 12) CAD without HF (n = 12) |
Laser Doppler imaging (LDI) coupled with transcutaneous iontophoresis of vasodilators | acetylcholine, sodium nitroprusside | Hyperaemia | Vasodilation due to Acth: No absolute values reported. p = 0.00099 (HF vs. controls). Vasodilation due to nitroprusside: p = 0.006 (HF vs. controls) |
Muscle-leg | ||||||
Prospective [16] | n = 22 | Healthy controls, age-matched (n = 43). | Histology (skeletal muscle biopsy of thigh) | Capillary density | Capillary-to-fibre ratio: 1.35 ± 0.32 vs. 2.53 ± 1.37, p = 0.006 | |
Prospective [29] | n = 7 | No controls. | Near-infrared spectroscopy: index for skeletal muscle haemoglobin oxygenation of thigh | Diffusion | Muscle deoxygenation overshoot was decreased after priming exercise, p = 0.041 |
Study Design | Study Population | Method (Measurement) | Stimulus | Microvascular Function Assessed | Outcome (SD/IQR) | Outcome Adjusted for Confounders |
---|---|---|---|---|---|---|
Heart-autopsy | ||||||
Retrospective [12] | Deceased: HFpEF (n = 124); Controls (no HF) (n = 104) |
Histology: microvessels/mm2 (microvascular density) | Rarefaction | Microvascular density: 961 (800–1370) vs. 1316 (1148–1467), p < 0.0001 | Not performed, unmatched population | |
Invasive coronary function assessment | ||||||
Retrospective [14] | CAG after positive stress test: HFpEF > 65 (n = 32); HFpEF < 65 (n = 24); Controls (n = 31) |
Invasive CFR and IMR | Adenosine | Hyperaemia | CFR: 1.94 ± 0.28 vs. 1.83 ± 0.32 vs. 3.24 ± 1.11, p ≤ 0.04 IMR: 39.2 ± 6.8 vs. 27.2 ± 6.4 vs. 18.3 ± 4.4, p ≤ 0.03 |
Age, sex, HT, DM, CKD, AF, BMI, LVMI. Unmatched controls |
Retrospective [9] | HFpEF (n = 162) | Invasive CFR and coronary blood flow (CBF) | Adenosine, acetylcholine | Hyperaemia | No absolute values reported. Mortality is increased in coronary MVD (HR 2.8–3.5). | Age, sex, BMI, DM, HT, hyperlipidaemia, smoking, Hb, creatinine, uric acid |
Retrospective [30] | HFpEF (n = 22); no HFpEF (n = 29) |
Invasive CFR and CBF | Adenosine, acetylcholine | Hyperaemia | CFR: 2.5 ± 0.6 vs. 3.2 ± 0.7, p = 0.0003 Median CBF % increase: 1 (−35;34) vs. 64 (−4;133), p = 0.002 |
Age, sex |
Prospective [31] | HFpEF with obstructive epicardial CAD (n = 38); HFpEF without epicardial CAD (n = 37) | CAG (CFR, coronary reactivity, IMR) and MRI | Adenosine, acetylcholine | Hyperaemia | CFR: 2.0(1.2–2.4) vs. 2.4(1.5–3.1), p = 0.06. IMR: 18(12–26) vs. 27(19–43), p = 0.02. 24% microvascular spasm due to Acth. | Clinical characteristics are compared between groups based on coronary results. |
Prospective (cross-sectional) [13] | Clinical indication for CAG: HFpEF (n = 30); Controls (n = 14) |
Invasive CFR and IMR | Adenosine | Hyperaemia | CFR: 2.55 ± 1.60 vs. 3.84 ± 1.89, p = 0.024 IMR: 26.7 ± 10.3 vs. 19.7 ± 9.7, p = 0.037 |
Exploratory analysis on age, BMI, GFR, BNP, echocardiographic data, hemodynamic data. Unmatched controls |
Retrospective [32] | Patients with angina presented to the ER: HFpEF (n = 155); Controls (n = 135) | Total myocardial blush grade score (TMBGS) | None, nitroglycerin | Blood flow | TMBGS: 5.6 ± 1.22 vs. 6.1 ± 1.26, p = 0.02 | Not performed, unmatched population |
Non-invasive coronary assessment | ||||||
Prospective [33] | HFpEF (n = 19); Matched healthy controls (n = 19) |
PET (C-acetate-11): myocardial blood flow (MBF) and myocardial oxygen consumption (MVO2) | Dobutamine | Blood flow, hyperaemia, diffusion | MBF increase: 78% vs. 151%, p = 0.0480 MVO2 increase: 59% vs. 86%, p = 0.0079 Absolute values during stress test not significantly different. |
LVH, Hb. Healthy controls were matched for age and sex. |
Retrospective [34] | Indication for cardiac PET: HFpEF (n = 78); HT without HF (n = 112); No HF no HT (n = 186) | PET (Rb-82): global myocardial flow reserve (MFR) | Dipyridamole | Hyperaemia | MFR: 2.16 ± 0.69 vs. 2.54 ± 0.80 vs. 2.89 ± 0.70, p ≤ 0.001 | Age, sex, BMI, smoking, DM, HT, hyperlipidaemia, HT, AF, statin use. Controls matched for HT. |
Retrospective [35] | Suspected CAD: Cohort without HF (n = 201) | PET (Rb-82): (CFR) | Regadenoson or dipyridamole | Hyperaemia | 18% of the patients had a HFpEF event during follow-up. Independent HR with CFR <2.0 of 2.47 (1.09–5.62) | In entire cohort: AF, CKD, troponin, LVEF, CFR, E/e’ septal |
Prospective [36] | HFpEF (n = 25); LVH (n = 13); Controls (n = 18) |
MRI (CFR) | Adenosine | Hyperaemia | CFR: 2.21 ± 0.55 vs. 3.05 ± 0.74 vs. 3.83 ± 0.73, p ≤ 0.002 | BNP, LVEF, E/e’, LA dimension |
Retrospective [37] | HFpEF without events (n = 137), with events (n = 26) | MRI (CFR) | Adenosine | Hyperaemia | CFR: 2.67 ± 0.64 vs. 1.93 ± 0.38 | Not performed |
Prospective [38] | HFpEF (n = 6); Post MI (n = 6); Healthy controls (n = 20) | MRI: intravascular volume of basal septum (IVV) | Gadofosveset | Permeability | IVV: 0.155 ± 0.033 vs. 0.146 ± 0.038 vs. 0.135 ± 0.018, p = 0.413 | Not performed, unmatched controls |
Prospective [10] | HFpEF (n = 202) | Echocardiography (CFR) | Adenosine | Hyperaemia | CFR: 2.13 ± 0.51 | Age, sex, BMI, AF, DM, CAD, smoking, LV mass, 6MWT, KCCQ, urinary albumin-creatinine ratio. No controls. |
Prospective [39] | HFpEF (n = 77); Healthy controls (n = 30) |
Echocardiography (CFR) | Adenosine | Hyperaemia | CFR: 1.7 ± 0.2 (with MVD) vs. 3.1 ± 0.4 (no MVD) vs. 3.4 ± 0.3 (control) | Age, LAVI, LVMI, LVEF, E/e’, 6MWT distance |
Clinical Factor | Measurement Method | Microvascular Bed Assessed | Effect on Microvascular Function |
---|---|---|---|
Age [34][69][72][73][74] | Skin, eye, skeletal muscle, heart | Function decreases by increasing age | |
Hormonal status [75][76][77][78] | Oestrogen levels, together with oestrogen receptor activity, are most accurate. Menopausal status and oral contraceptive therapy use are alternative surrogate markers. | Skin, skeletal muscle, heart | Function decreases with lower oestrogen activity |
Hypercholesterolemia [70][79][80] | Serum cholesterol panel | Skin, eye, heart | Function decreases with higher serum low-density lipoprotein cholesterol levels |
Hyperglycaemia [81][82] | Glucose tolerance test, fasting glucose, HbA1c | Skin, eye, heart | Function decreases with higher plasma glucose levels |
Hypertension [34][36][69][83][84] | 24-h systolic blood pressure shows the highest correlation | Skin, eye, skeletal muscle, heart | Function decreases with higher systolic blood pressure and by duration of hypertension |
Dietary intake [85] | Caffeine | Skin | Function is temporarily increased |
Dietary intake [86][87] | High-fat diet | Skin, heart | Function is temporarily decreased |
Physical inactivity [29][88][89][90] | 24-h accelerometer, physical activity questionnaire | Skin, eye, skeletal muscle | Function decreases with more physical inactivity. |
Obesity [8][69][91][92] | Waist circumference is more correlated than BMI or BSA. | Skin, eye, skeletal muscle, heart | Function decreases with increasing level of obesity |
Sex [93][94] | Skin, eye, skeletal muscle, heart | Effect on function depends on other confounders. | |
Smoking [74][95] | Self-reported use | Skin, eye, heart | Function decreases with smoking and more pack years. |
Systemic MVD is present in HFpEF, based on interpretation of abundant data from many correlational studies that show impairments in microvascular function, both endothelium-dependent and endothelium-independent, in different vascular beds. MVD should be seen as a continuum between function and dysfunction, which can influence HFpEF and comorbidity progression, and vice versa. Hitherto, due to a lack of clear causative evidence, it remains unknown how systemic MVD could drive HFpEF.
Furthermore, HFpEF patients unequally show different elements of MVD, which might reflect different underlying mechanisms and therapeutic targets. Future research on MVD and HFpEF is, therefore, needed to uncover the true diagnostic and therapeutic value of microvascular assessments. This will require more uniformity and confounder considerations in study design, analyses, and reporting. However, the incorporation of peripheral microvascular assessments is feasible and should be considered in clinical HFpEF trials.