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Coronary microvascular rarefaction and myocardial fibrosis in heart failure with preserved ejection fraction.

ABSTRACT: Characterization of myocardial structural changes in heart failure with preserved ejection fraction (HFpEF) has been hindered by the limited availability of human cardiac tissue. Cardiac hypertrophy, coronary artery disease (CAD), coronary microvascular rarefaction, and myocardial fibrosis may contribute to HFpEF pathophysiology.We identified HFpEF patients (n=124) and age-appropriate control subjects (noncardiac death, no heart failure diagnosis; n=104) who underwent autopsy. Heart weight and CAD severity were obtained from the autopsy reports. With the use of whole-field digital microscopy and automated analysis algorithms in full-thickness left ventricular sections, microvascular density (MVD), myocardial fibrosis, and their relationship were quantified. Subjects with HFpEF had heavier hearts (median, 538 g; 169% of age-, sex-, and body size-expected heart weight versus 335 g; 112% in controls), more severe CAD (65% with ?1 vessel with >50% diameter stenosis in HFpEF versus 13% in controls), more left ventricular fibrosis (median % area fibrosis, 9.6 versus 7.1) and lower MVD (median 961 versus 1316 vessels/mm(2)) than control (P<0.0001 for all). Myocardial fibrosis increased with decreasing MVD in controls (r=-0.28, P=0.004) and HFpEF (r=-0.26, P=0.004). Adjusting for MVD attenuated the group differences in fibrosis. Heart weight, fibrosis, and MVD were similar in HFpEF patients with CAD versus without CAD.In this study, patients with HFpEF had more cardiac hypertrophy, epicardial CAD, coronary microvascular rarefaction, and myocardial fibrosis than controls. Each of these findings may contribute to the left ventricular diastolic dysfunction and cardiac reserve function impairment characteristic of HFpEF.

SUBMITTER: Mohammed SF

PROVIDER: S-EPMC4324362 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature

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Coronary microvascular rarefaction and myocardial fibrosis in heart failure with preserved ejection fraction.

Mohammed Selma F SF Hussain Saad S Mirzoyev Sultan A SA Edwards William D WD Maleszewski Joseph J JJ Redfield Margaret M MM

Circulation 20141231 6

<h4>Background</h4>Characterization of myocardial structural changes in heart failure with preserved ejection fraction (HFpEF) has been hindered by the limited availability of human cardiac tissue. Cardiac hypertrophy, coronary artery disease (CAD), coronary microvascular rarefaction, and myocardial fibrosis may contribute to HFpEF pathophysiology.<h4>Methods and results</h4>We identified HFpEF patients (n=124) and age-appropriate control subjects (noncardiac death, no heart failure diagnosis; n ...[more]

PMID: 25552356

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Project description:Heart failure with preserved ejection fraction (HFpEF) is an increasingly studied entity accounting for 50% of all diagnosed heart failure and that has claimed its own dignity being markedly different from heart failure with reduced EF in terms of etiology and natural history (Graziani et al., 2018). Recently, a growing body of evidence points the finger toward microvascular dysfunction as the major determinant of the pathological cascade that justifies clinical manifestations (Crea et al., 2017). The high burden of comorbidities such as metabolic syndrome, hypertension, atrial fibrillation, chronic kidney disease, obstructive sleep apnea, and similar, could lead to a systemic inflammatory state that impacts the physiology of the endothelium and the perivascular environment, engaging complex molecular pathways that ultimately converge to myocardial fibrosis, stiffening, and dysfunction (Paulus and Tschope, 2013). These changes could even self-perpetrate with a positive feedback where hypoxia and locally released inflammatory cytokines trigger interstitial fibrosis and hypertrophy (Ohanyan et al., 2018). Identifying microvascular dysfunction both as the cause and the maintenance mechanism of this condition has opened the field to explore specific pharmacological targets like nitric oxide (NO) pathway, sarcomeric titin, transforming growth factor beta (TGF-β) pathway, immunomodulators or adenosine receptors, trying to tackle the endothelial impairment that lies in the background of this syndrome (Graziani et al., 2018;Lam et al., 2018). Yet, many questions remain, and the new data collected still lack a translation to improved treatment strategies. To further elaborate on this tangled and exponentially growing topic, we will review the evidence favoring a microvasculature-driven etiology of this condition, its clinical correlations, the proposed diagnostic workup, and the available/hypothesized therapeutic options to address microvascular dysfunction in the failing heart.

Project description:BACKGROUND:The role of coronary microvascular disease and its impact on functional and energetic reserve in heart failure with preserved ejection fraction (HFpEF) remains unclear. We hypothesized that in response to submaximal pharmacologic stress (dobutamine), patients with HFpEF have impairment in left ventricular (LV) myocardial mechanical (external work [EW]), energetic (myocardial O2 consumption [MVO2]), and myocardial blood flow (MBF) reserve. We further assessed whether coupling of MBF to EW is impaired in HFpEF and associated with compensatory increases or pathological decreases in myocardial O2 extraction. Lastly, we assessed whether coupling of MVO2 to EW (mechanical efficiency) was impaired in HFpEF. METHODS AND RESULTS:In prospectively enrolled patients with HFpEF (n=19) and age/sex-matched healthy controls (n=19), we performed 11C-acetate positron emission tomography assessing MVO2 and MBF at rest and during dobutamine infusion. EW was calculated as stroke volume (echo)×end-systolic pressure×heart rate. At rest, compared with controls, patients with HFpEF had higher LV EW, MVO2, and MBF. With dobutamine, LV EW, MVO2, and MBF increased in both HFpEF and controls; however, the magnitude of increases was significantly smaller in HFpEF. In both groups, MBF increased in relation to EW, but in HFpEF, the slope of the relationship was significantly smaller than in controls. Myocardial O2 extraction was increased in HFpEF. Mechanical efficiency was similar in HFpEF and controls. In a post hoc analysis, HFpEF patients with LV hypertrophy (n=10) had significant reductions in LV mechanical efficiency relative to controls. CONCLUSIONS:In HFpEF during submaximal dobutamine stress, there is myocardial mechanical-, energetic- and flow-reserve dysfunction with impaired coupling of blood flow to demand and slight increases in myocardial O2 extraction. These findings provide evidence that coronary microvascular dysfunction is present in HFpEF, limits O2 supply relative to demand, and is associated with reserve dysfunction.

Project description:ImportanceCoronary artery disease (CAD) and coronary microvascular dysfunction (CMD) may contribute to the pathophysiologic characteristics of heart failure with preserved ejection fraction (HFpEF). However, the prevalence of CAD and CMD have not been systematically studied.ObjectiveTo examine the prevalence of CAD and CMD in hospitalized patients with HFpEF.Design, setting, and participantsA total of 106 consecutive patients hospitalized with HFpEF were evaluated in this prospective, multicenter, cohort study conducted between January 2, 2017, and August 1, 2018; data analysis was performed from March 4 to September 6, 2019. Participants underwent coronary angiography with guidewire-based assessment of coronary flow reserve, index of microvascular resistance, and fractional flow reserve, followed by coronary vasoreactivity testing. Cardiac magnetic resonance imaging was performed with late gadolinium enhancement and assessment of extracellular volume. Myocardial perfusion was assessed qualitatively and semiquantitatively using the myocardial-perfusion reserve index.Main outcomes and measuresThe prevalence of obstructive epicardial CAD, CMD, and myocardial ischemia, infarction, and fibrosis.ResultsOf 106 participants enrolled (53 [50%] women; mean [SD] age, 72 [9] years), 75 had coronary angiography, 62 had assessment of coronary microvascular function, 41 underwent coronary vasoreactivity testing, and 52 received cardiac magnetic resonance imaging. Obstructive epicardial CAD was present in 38 of 75 participants (51%, 95% CI, 39%-62%); 19 of 38 (50%; 95% CI, 34%-66%) had no history of CAD. Endothelium-independent CMD (ie, coronary flow reserve <2.0 and/or index of microvascular resistance ≥25) was identified in 41 of 62 participants (66%; 95% CI, 53%-77%). Endothelium-dependent CMD (ie, abnormal coronary vasoreactivity) was identified in 10 of 41 participants (24%; 95% CI, 13%-40%). Overall, 45 of 53 participants (85%; 95% CI, 72%-92%) had evidence of CMD and 29 of 36 (81%; 95% CI, 64%-91%) of those without obstructive epicardial CAD had CMD. Cardiac magnetic resonance imaging findings included myocardial-perfusion reserve index less than or equal to 1.84 (ie, impaired global myocardial perfusion) in 29 of 41 patients (71%; 95% CI, 54%-83%), visual perfusion defect in 14 of 46 patients (30%; 95% CI, 19%-46%), ischemic late gadolinium enhancement (ie, myocardial infarction) in 14 of 52 patients (27%; 95% CI, 16%-41%), and extracellular volume greater than 30% (ie, diffuse myocardial fibrosis) in 20 of 48 patients (42%; 95% CI, 28%-56%). Patients with obstructive CAD had more adverse events during follow-up (28 [74%]) than those without obstructive CAD (17 [46%]).Conclusions and relevanceIn this cohort study, 91% of patients with HFpEF had evidence of epicardial CAD, CMD, or both. Of those without obstructive CAD, 81% had CMD. Obstructive epicardial CAD and CMD appear to be common and often unrecognized in hospitalized patients with HFpEF and may be therapeutic targets.

Dataset Information

Coronary microvascular rarefaction and myocardial fibrosis in heart failure with preserved ejection fraction.

Publications

Coronary microvascular rarefaction and myocardial fibrosis in heart failure with preserved ejection fraction.

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