Capillary vascular density in the retina of hypertensive patients is associated with a non-dipping pattern independent of mean ambulatory blood pressure

Optical coherence tomography angiography in cardiovascular disease

Endothelial dysfunction and microvascular remodeling underly the development and progression of a host of cardiovascular disease (CVD). However, current methods to assess coronary epicardial microvascular function are invasive, time-intensive, and costly. Optical coherence tomography angiography (OCTA) is an established technology within ophthalmology that provides a quick, noninvasive assessment of vascular structures within the retina. As a growing body of evidence reveals strong associations between the retinal changes on OCTA and the development and progression of CVD, OCTA may indeed be a surrogate test for end-organ dysfunction. OCTA has potential to enhance diagnostic performance, refine cardiovascular risk assessment, strengthen prognostication, and ultimately, improve patient care. We explore the current literature on OCTA in cardiovascular diseases to summarize the clinical utility of retinal OCTA imaging and discuss next-generation cardiovascular applications.

Ocular biomarkers: useful incidental findings by deep learning algorithms in fundus photographs

BACKGROUND/OBJECTIVES

Artificial intelligence can assist with ocular image analysis for screening and diagnosis, but it is not yet capable of autonomous full-spectrum screening. Hypothetically, false-positive results may have unrealized screening potential arising from signals persisting despite training and/or ambiguous signals such as from biomarker overlap or high comorbidity. The study aimed to explore the potential to detect clinically useful incidental ocular biomarkers by screening fundus photographs of hypertensive adults using diabetic deep learning algorithms.

SUBJECTS/METHODS

Patients referred for treatment-resistant hypertension were imaged at a hospital unit in Perth, Australia, between 2016 and 2022. The same 45° colour fundus photograph selected for each of the 433 participants imaged was processed by three deep learning algorithms. Two expert retinal specialists graded all false-positive results for diabetic retinopathy in non-diabetic participants.

RESULTS

Of the 29 non-diabetic participants misclassified as positive for diabetic retinopathy, 28 (97%) had clinically useful retinal biomarkers. The models designed to screen for fewer diseases captured more incidental disease. All three algorithms showed a positive correlation between severity of hypertensive retinopathy and misclassified diabetic retinopathy.

CONCLUSIONS

The results suggest that diabetic deep learning models may be responsive to hypertensive and other clinically useful retinal biomarkers within an at-risk, hypertensive cohort. Observing that models trained for fewer diseases captured more incidental pathology increases confidence in signalling hypotheses aligned with using self-supervised learning to develop autonomous comprehensive screening. Meanwhile, non-referable and false-positive outputs of other deep learning screening models could be explored for immediate clinical use in other populations.

Ambulatory blood pressure after 12 weeks of quadruple combination of quarter doses of blood pressure medication vs. standard medication

BACKGROUND

A combination of four ultra-low-dose blood pressure (BP) medications lowered office BP more effectively than initial monotherapy in the QUARTET trial. The effects on average ambulatory BP changes at 12 weeks have not yet been reported in detail.

METHODS

Adults with hypertension who were untreated or on monotherapy were eligible for participation. Overall, 591 participants were randomized to either the quadpill (irbesartan 37.5 mg, amlodipine 1.25 mg, indapamide 0.625 mg, and bisoprolol 2.5 mg) or monotherapy control (irbesartan 150 mg). The difference in 24-h, daytime, and night-time systolic and diastolic ambulatory BP at 12 weeks along further metrics were predefined secondary outcomes.

RESULTS

Of 576 participants, 289 were randomized to the quadpill group and 287 to the monotherapy group. At 12 weeks, mean 24-h ambulatory SBP and DBP were 7.7 [95% confidence interval (95% CI) 9.6-5.8] and 5.3 (95% CI: 6.5-4.1) mmHg lower in the quadpill vs. monotherapy group ( P  < 0.001 for both). Similar reductions in the quadpill group were observed for daytime (8.1/5.7 mmHg lower) and night-time (6.3/4.0 mmHg lower) BP at 12 weeks (all P  < 0.001) compared to monotherapy. The rate of BP control (24-h average BP < 130/80 mmHg) at 12 weeks was higher in the quadpill group (77 vs. 50%; P  < 0.001). The reduction in BP load was also more pronounced with the quadpill.

CONCLUSION

A quadruple quarter-dose combination compared with monotherapy resulted in greater ambulatory BP lowering across the entire 24-h period with higher ambulatory BP control rates and reduced BP variability at 12 weeks. These findings further substantiate the efficacy of an ultra-low-dose quadpill-based BP lowering strategy.

Early Left Ventricular Dysfunction and Non-Dipping: When Ejection Fraction is Not Enough. A Meta-Analysis of Speckle tracking Echocardiography Studies

BACKGROUND

There is evidence that a reduced nocturnal fall in blood pressure (BP) entails an increased risk of hypertensive-mediated organ damage (HMOD) and cardiovascular events. Most studies focusing on left ventricular (LV) systolic function, assessed by conventional LV ejection fraction (LVEF) in non-dippers compared to dippers failed to detect significant differences. To provide a new piece of information on LV systolic dysfunction in the non-dipping setting, we performed a meta-analysis of speckle tracking echocardiography (STE) studies investigating LV global longitudinal strain (GLS), a more sensitive index of LV systolic function.

METHODS

A computerized search was performed using PubMed, OVID, EMBASE, and Cochrane library databases from inception until 31 July, 2022. Full articles reporting data on LV GLS and LVEF in non-dippers and dippers were considered suitable.

RESULTS

A total of 648 non-dipper and 530 dipper individuals were included in 9 studies. LV GLS was worse in non-dipper than in their dipper counterparts (-18.4 ± 0.30 vs. -20.1 ± 0.23%, standard means difference [SMD]: 0.73 ± 0.14, confidence interval [CI]: 0.46/1.00, P < 0.0001) whereas this was not the case for LVEF (61.4 ± 0.8 and 62.0 ± 0.8%, respectively), SMD: --0.15 ± 0.09, CI: -0.32/0.03, P = 1.01). A meta-regression analysis between nighttime systolic BP and myocardial GLS showed a significant, relationship between these variables (coefficient 0.085, P < 0.0001).

CONCLUSIONS

Our findings suggest that early changes in LV systolic function not detectable by conventional echocardiography in the non-dipping setting can be unmasked by STE; implementation of STE in current practice may improve the detection of HMOD of adverse prognostic significance in individuals with altered circadian BP rhythm.

Evaluation of Circulating Platelet Extracellular Vesicles and Hypertension Mediated Organ Damage

Elevated circulating platelet-derived extracellular vesicles (pEVs) have been associated with arterial hypertension. The role of hypertension-mediated organ damage (HMOD) to induce EV release is still unknown. We studied the micro- and macro-vascular changes (retinal vascular density and pulse wave velocity), endothelial function (flow-mediated vasodilation of brachial artery and finger plethysmography), and assessed the psychosocial status (anxiety and depression) in hypertensive patients to determine their relationship with EV release. Pulse wave velocity showed a significant positive correlation with pEVs (r = 0.33; p = 0.01). Systolic blood pressure (SBP) negatively correlated with retinal vascularity. The superficial retinal vascular plexus density in the whole image showed a significant negative correlation with 24 h SBP (r = −0.38, p < 0.01), day-SBP (r = −0.35, p = 0.01), and night-SBP (r = −0.27, p = 0.04). pEVs did not show significant associations with microvascular damage (retinal vascular density), endothelial function (flow-mediated vasodilation of brachial artery and finger plethysmography), or psychosocial status (anxiety and depression). Our results indicate that the pEV levels were associated with macrovascular damage measured by PWV, whereas no significant association between pEVs and microvascular damage, endothelial function, or emotional status could be detected. The potential utility of pEV in clinical practice in the context of HMOD may be limited to macrovascular changes.

Impact of various night-time period definitions on nocturnal ambulatory blood pressure

BACKGROUND

Several definitions of night-time BP exist for the calculation of nocturnal blood pressure (BP) based on 24-h BP measurements. How much these methods differ regarding the resulting nocturnal blood pressure values, under which circumstances these differences become clinically meaningful, and under which circumstances diary-adjusted measurements should be used preferentially remains uncertain.

METHODS

Data of 512 24-h BP recordings were analysed regarding differences in nocturnal BP based on three alternative definitions of night-time: 2300-0700 h, 0100-0500 h, and diary-adjusted measures.

RESULTS

Mean systolic nocturnal BP between 2300-0700 h was 2.5 mmHg higher than between 0100 and 0500 h and 1.6 mmHg higher than diary adjusted estimates. Up to 38.3% of individuals showed BP differences of more than 5 mmHg when comparing temporal definitions of night-time, resulting in significant proportions of individuals being re-classified as hypertensive. When diary-derived sleeping patterns differed by less than 2 h from the 2300 to 0700 h fixed time definition, mean BP discrepancies remained below 3 mmHg. Absolute time discrepancies between diary and 2300-0700 h fixed time definition of 2-4, 4-8 or at least 8 h led to SBP/DBP differences of 4.1/3.1, 6.8/6.1, and 14.5/9.1mmHg, respectively.

CONCLUSION

Average differences of nocturnal BP between varying definitions in study/cohort data are small and would be of limited relevance in many settings. However, substantial differences can be observed in individual cases, which may affect clinical decision-making in specific patients. In patients whose sleeping patterns differs by more than 2 h from defined fixed night-times, diaries should be used for adjustment.

Circulating platelet-derived extracellular vesicles correlate with night-time blood pressure and vascular organ damage and may represent an integrative biomarker of vascular health

Elevated office blood pressure (BP) has previously been associated with increased levels of circulating extracellular vesicles (EVs). The present study aimed to assess the relationship between levels of platelet derived EVs, ambulatory BP parameters, and pulse wave velocity as a marker of macrovascular organ damage. A total of 96 participants were included in the study. Platelet-derived extracellular vesicles (pEVs) were evaluated by flow cytometry (CD41+/Annexin v+). BP evaluation included unobserved automated office BP and ambulatory BP monitoring. Carotid-femoral pulse wave velocity (PWV) was measured as a marker of macrovascular damage. pEVs correlated with nocturnal systolic BP (r = 0.31; p = .003) and nocturnal dipping (r = -0.29; p = .01) in univariable analysis. Multivariable regression models confirmed robustness of the association of EVs and nocturnal blood pressure (p = .02). In contrast, systolic office, 24h- and daytime-BP did not show significant associations with pEVs. No correlations were found with diastolic BP. Circulating pEVs correlated with pulse wave velocity (r = 0.25; p = .02). When comparing different hypertensive phenotypes, higher levels of EVs and PWV were evident in patients with sustained hypertension compared to patients with white coat HTN and healthy persons. Circulating platelet derived EVs were associated with nocturnal BP, dipping, and PWV. Given that average nocturnal BP is the strongest predictor of CV events, platelet derived EVs may serve as an integrative marker of vascular health, a proposition that requires testing in prospective clinical trials.

New Noninvasive Methods to Evaluate Microvascular Structure and Function

The structural and functional alterations of microvessels are detected because of physiological aging and in several cardiometabolic diseases, including hypertension, diabetes, and obesity. The small resistance arteries of these patients show an increase in the media or total wall thickness to internal lumen diameter ratio (MLR or WLR), often accompanied by endothelial dysfunction. For decades, micromyography has been considered as a gold standard method for evaluating microvascular structural alterations through the measurement of MLR or WLR of subcutaneous small vessels dissected from tissue biopsies. Micromyography is the most common and reliable method for assessing microcirculatory endothelial function ex vivo, while strain-gauge venous plethysmography is considered the reference technique for in vivo studies. Recently, several noninvasive methods have been proposed to extend the microvasculature evaluation to a broader range of patients and clinical settings. Scanning laser Doppler flowmetry and adaptive optics are increasingly used to estimate the WLR of retinal arterioles. Microvascular endothelial function may be evaluated in the retina by flicker light stimulus, in the finger by tonometric approaches, or in the cutaneous or sublingual tissues by laser Doppler flowmetry or intravital microscopy. The main limitation of these techniques is the lack of robust evidence on their prognostic value, which currently reduces their widespread use in daily clinical practice. Ongoing and future studies will overcome this issue, hopefully moving the noninvasive assessment of the microvascular function and structure from bench to bedside.

Automatic data extraction from 24 hour blood pressure measurement reports of a large multicenter clinical trial

BACKGROUND AND OBJECTIVES

Ambulatory blood pressure monitoring (ABPM) is usually reported in descriptive values such as circadian averages and standard deviations. Making use of the original, individual blood pressure measurements may be advantageous, particularly for research purposes, as this increases the flexibility of the analytical process, enables alternative statistical analyses and provide novel insights. Here we describe the development of a new multistep, hierarchical data extraction algorithm to collect raw data from .pdf reports and text files as part of a large multi-center clinical study.

METHODS

Original reports were saved in a nested file system, from which they were automatically extracted, read and saved into databases with custom made programs written in Python 3. Data were further processed, cleaned and relevant descriptive statistics such as averages and standard deviations calculated according to a variety of definitions of day- and night-time. Additionally, data control mechanisms for manual review of the data and programmatic auto-detection of extraction errors was implemented as part of the project.

RESULTS

The developed algorithm extracted 97% of the data automatically, the missing data consisted mostly of reports that were saved incorrectly or not formatted in the specified way. Manual checks comparing samples of the extracted data to original reports indicated a high level of accuracy of the extracted data, no errors introduced due to flaws in the extraction software were detected in the extracted dataset.

CONCLUSIONS

The developed multistep, hierarchical data extraction algorithm facilitated collection from different file formats and paired with database cleaning and data processing steps led to an effective and accurate assembly of raw ABPM data for further and adjustable analyses. Manual work was minimized while data quality was ensured with standardized, reproducible procedures.