Coronary Microvascular Dysfunction and Heart Failure with Preserved Ejection Fraction - implications for Chronic Inflammatory Mechanisms

The prevalence of coronary microvascular dysfunction (CMD) in heart failure with preserved ejection fraction (HFpEF): a systematic review and meta-analysis

To date, studies on the prevalence of coronary microvascular dysfunction (CMD) in heart failure with preserved ejection fraction (HFpEF) have not been summarized and analyzed as a whole. We conducted this systematic review and meta-analysis to assess the prevalence of CMD in patients with HFpEF. The PubMed, Cochrane, and Embase databases were searched from dates of inception until May 1, 2023. The primary outcome was the prevalence of CMD in patients with HFpEF, and values of CMD prevalence were pooled using a random-effects model. In total, 10 studies involving 1267 patients, including 822 with HFpEF and 445 without HFpEF, were included. The pooled prevalence of CMD in patients with HFpEF was 71% (95% CI, 0.63-0.79). In the subgroup analysis, the prevalence of CMD was 79% (95% CI, 0.71-0.87) by invasive measurement and 66% (95% CI, 0.54-0.77) by noninvasive measurement and 67% (95% CI, 0.52-0.82) with CFR < 2.0 and 75.0% (95% CI, 0.71-0.79) with CFR < 2.5. The prevalence of endothelium-independent CMD and endothelium-dependent CMD was 62% (95% CI, 0.53-0.72) and 50% (95% CI, 0.19-0.81), respectively. The prevalence of CMD was 74% (95% CI = 0.69-0.79) and 66% (95% CI = 0.41-0.90) in prospective and retrospective studies, respectively. Compared with the control group, patients with HFpEF had a significantly lower CFR (MD =  - 1.28, 95% CI =  - 1.82 to - 0.74, P < 0.01) and a higher prevalence of CMD (RR = 2.21, 95% CI = 1.52 to 3.20, P < 0.01). Qualitative analysis demonstrated that CMD might be associated with poor clinical outcomes in patients with HFpEF. In conclusion, this is the first systematic review and meta-analysis of all studies reporting the prevalence of CMD in patients with HFpEF. Our study demonstrates that CMD is common in patients with HFpEF and might be associated with poor clinical outcomes in these patients. Clinicians should attach importance to CMD in the diagnosis and treatment of HFpEF. The number of studies in this field is relatively small. Therefore, more high-quality studies are needed to explore the diagnostic and prognostic value of CMD and the potential role of CMD as a therapeutic target in patients with HFpEF.

Endothelial Dysfunction and Heart Failure with Preserved Ejection Fraction-An Updated Review of the Literature

Heart failure (HF) is a clinical syndrome consisting of typical symptoms and signs due to structural and/or functional abnormalities of the heart, resulting in elevated intracardiac pressures and/or inadequate cardiac output. The vascular system plays a crucial role in the development and progression of HF regardless of ejection fraction, with endothelial dysfunction (ED) as one of the principal features of HF. The main ED manifestations (i.e., impaired endothelium-dependent vasodilation, increased oxidative stress, chronic inflammation, leukocyte adhesion, and endothelial cell senescence) affect the systemic and pulmonary haemodynamic and the renal and coronary circulation. The present review is aimed to discuss the contribution of ED to HF pathophysiology-in particular, HF with preserved ejection fraction-ED role in HF patients, and the possible effects of pharmacological and non-pharmacological approaches. For this purpose, relevant data from a literature search (PubMed, Scopus, EMBASE, and Medline) were reviewed. As a result, ED, assessed via venous occlusion plethysmography or flow-mediated dilation, was shown to be independently associated with poor outcomes in HF patients (e.g., mortality, cardiovascular events, and hospitalization due to worsening HF). In addition, SGLT2 inhibitors, endothelin antagonists, endothelial nitric oxide synthase cofactors, antioxidants, and exercise training were shown to positively modulate ED in HF. Despite the need for future research to better clarify the role of the vascular endothelium in HF, ED represents an interesting and promising potential therapeutic target.

Pathophysiology and Outcomes of Endothelium Function in Coronary Microvascular Diseases: A Systematic Review of Randomized Controlled Trials and Multicenter Study

BACKGROUND

Coronary macrovascular disease is a concept that has been well-studied within the literature and has long been the subject of debates surrounding coronary artery bypass grafting (CABG) vs. Percutaneous Coronary Intervention (PCI). ISCHEMIA trial reported no statistical difference in the primary clinical endpoint between initial invasive management and initial conservative management, while in the ORBITA trial PCI did not improve angina frequency score significantly more than placebo, albeit PCI resulted in more patient-reported freedom from angina than placebo. However, these results did not prove the superiority of the PCI against OMT, therefore do not indicate the benefit of PCI vs. the OMT. Please rephrase the sentence. We reviewed the role of different factors responsible for endothelial dysfunction from recent randomized clinical trials (RCTs) and multicentre studies.

METHODS

A detailed search strategy was performed using a dataset that has previously been published. Data of pooled analysis include research articles (human and animal models), CABG, and PCI randomized controlled trials (RCTs). Details of the search strategy and the methods used for data pooling have been published previously and registered with Open-Source Framework.

RESULTS

The roles of nitric oxide (NO), endothelium-derived contracting factors (EDCFs), and vasodilator prostaglandins (e.g., prostacyclin), as well as endothelium-dependent hyperpolarization (EDH) factors, are crucial for the maintenance of vasomotor tone within the coronary vasculature. These homeostatic mechanisms are affected by sheer forces and other several factors that are currently being studied, such as vaping. The role of intracoronary testing is crucial when determining the effects of therapeutic medications with further studies on the horizon.

CONCLUSION

The true impact of coronary microvascular dysfunction (CMD) is perhaps underappreciated, which supports the role of medical therapy in determining outcomes. Ongoing trials are underway to further investigate the role of therapeutic agents in secondary prevention.