Coronary Microvascular Dysfunction and Hypertension: A Bond More Important than We Think

The effect of renal denervation in microcirculation: focusing on coronary microvascular dysfunction

Arterial hypertension is one of the most prevalent cardiovascular pathologies worldwide. Considering the increased rates of uncontrolled hypertension and treatment non-adherence, catheter-based methods, with the most prominent being renal denervation, have been recently included in international guidelines for the management of the pathology, naming the method the third pillar in hypertension management. However, sympathetic overactivation is not only a major pathophysiologic driver in hypertension, but in other cardiovascular pathologies as well. Considering the effect of renal denervation in hypertension-mediated target organ damage, as well as the pleotropic effects of this modality, recent evidence have evaluated the modality in coronary microvascular dysfunction (CMD). Interestingly, despite preclinical data showcase a benefit of renal denervation in microcirculatory homeostasis, with enhancement of endothelial-mediated vasodilation and reduction of inflammation, these effects have failed to be translated into clinical benefit, with the limited, to date, non-interventional studies in coronary microcirculation reporting neutral effects. Therefore, this review aims to delineate the pathophysiological processes which relate microvascular dysfunction with hypertension, discuss the effect of the procedure in hypertension-mediated target organ damage, analyze preclinical and clinical data on the safety and efficacy of renal denervation in improving microcirculatory indices, as well as provide future directions for this novel field.

Cardiac intravoxel incoherent motion diffusion-weighted imaging to assess myocardial microcirculation dysfunction in hypertension

Background

Myocardial microcirculation dysfunction is the most potent predictor of adverse cardiovascular events in hypertension. The current study aimed to apply intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) to assess hypertension-related microcirculation dysfunction.

Methods

In this prospective study, 102 participants were recruited from our hospital and underwent cardiac magnetic resonance (CMR) examination on a 3T scanning system. Hypertensive patients were divided into 3 subgroups based on blood pressure (BP) types. Two experienced CMR radiologists independently analyzed all images, and Bland-Altman analysis was applied to assess intra- and inter-observer reproducibility. Cardiac function indexes and IVIM-DWI parameters were compared between the hypertension and healthy control groups, as well as among the three hypertension subgroups.

Results

Totally 62 participants with hypertension and 27 healthy controls were included. 13 participants were excluded for poor quality of IVIM-DWI images. Significantly higher maximal left ventricular wall thickness (10.3±2.0 vs. 8.6±1.4 mm, P<0.001) and left ventricular mass index (49.0±9.1 vs. 42.1±7.5 g/m2, P<0.05) were observed inhypertension group compared with healthy control group. There were significant statistical differences in pseudo diffusion (D*) between them (81.3±16.3 vs. 111.8±18.9 mm2/s, P<0.001), as well as among the three hypertension subgroups (99.4±13.9 vs. 79.7±10.6 vs. 67.1±6.6 mm2/s, P<0.001). Participants with poor quality of IVIM-DWI images had higher heart rates (72.2±10.0 vs. 62.0±8.1 bpm, P<0.001).

Conclusions

IVIM-DWI is feasible for quantitatively evaluating myocardial microcirculation dysfunction in hypertension. The D* parameter has a potential value for assessing the severity of microcirculation dysfunction in different BP categories.

Microvascular rarefaction caused by the NOTCH signaling pathway is a key cause of TKI-apatinib-induced hypertension and cardiac damage

With the advancement of tumour-targeted therapy technology, the survival of cancer patients has continued to increase, and cardiovascular events have gradually become an important cause of death in cancer patients. This phenomenon occurs due to adverse cardiovascular reactions caused by the cardiovascular toxicity of antitumour therapy. Moreover, the increase in the proportion of elderly patients with cancer and cardiovascular diseases is due to the extension of life expectancy. Hypertension is the most common cardiovascular side effect of small molecule tyrosine kinase inhibitors (TKIs). The increase in blood pressure induced by TKIs and subsequent cardiovascular complications and events affect the survival and quality of life of patients and partly offset the benefits of antitumour therapy. Many studies have confirmed that in the pathogenesis of hypertension, arterioles and capillary thinness are involved in its occurrence and development. Our previous findings showing that apatinib causes microcirculation rarefaction of the superior mesenteric artery and impaired microvascular growth may inspire new therapeutic strategies for treating hypertension. Thus, by restoring microvascular development and branching patterns, total peripheral resistance and blood pressure are reduced. Therefore, exploring the key molecular targets of TKIs that inhibit the expression of angiogenic factors and elucidating the specific molecular mechanism involved are key scientific avenues for effectively promoting endothelial cell angiogenesis and achieving accurate repair of microcirculation injury in hypertension patients.