Impact of aortic root size on left ventricular afterload and stroke volume

Ultrasound images of the ascending aorta of anesthetized northern fur seals and Steller sea lions confirm that the aortic bulb maintains continuous blood flow

The increased size and enhanced compliance of the aortic bulb-the enlargement of the ascending aorta-are believed to maintain blood flow in pinnipeds during extended periods of diastole induced by diving bradycardia. The aortic bulb has been described ex vivo in several species of pinnipeds, but in vivo measurements are needed to investigate the relationship between structure and function. We obtained ultrasound images using electrocardiogram-gated transesophageal echocardiography during anesthesia and after atropine administration to assess the relationship between aortic bulb anatomy and cardiac function (heart rate, stroke volume, cardiac output) in northern fur seals (Callorhinus ursinus) and Steller sea lions (Eumetopias jubatus). We observed that the aortic bulb in northern fur seals and Steller sea lions expands during systole and recoils over the entire diastolic period indicating that blood flow is maintained throughout the entire cardiac cycle as expected. The stroke volumes we measured in the fur seals and sea lions fit the values predicted based on body size in mammals and did not change with increased heart rates, suggesting that greater stroke volumes are not needed for aortic bulb function. Overall, our results suggest that peripheral vasoconstriction during diving is sufficient to modulate the volume of blood in the aortic bulb to ensure that flow lasts over the entire diastolic period. These results indicate that the shift of blood into the aortic bulb of pinnipeds is a fundamental mechanism caused by vasoconstriction while diving, highlighting the importance of this unique anatomical adaptation.

Longitudinal analysis of thoracic aortic expansion in non-syndromic real-world patients

Remodeling of the thoracic aorta is commonly seen and viewed as a precursor to an aortic aneurysm. However, while aneurysms have been shown to expand at a rate of approximately 1 mm annually, the expansion of the pre-aneurysmal aorta is poorly characterized, especially in relation to age, gender, and aortic size per se. We identified patients that had undergone echocardiography at least twice at a large university medical center. Diagnosis codes, medications, and blood test results were obtained from hospital records. Syndromic patients were excluded (e.g., Marfan's syndrome, bicuspid aortic valve). Final population comprised n = 24,928 patients (median age 61.2 years (inter-quartile range (IQR): 50.6-71.5); 55.8% males) that had undergone a median of 3 echocardiograms (2-4; range 2-27) during a median of 4.0 years (IQR: 2.3-6.2). Hypertension was present in 39.6% of patients and diabetes in 20.7%, median LV ejection fraction was 56.0% (IQR: 41.0-62.0). Aortic size measurements were analyzed in mixed models while clustering on individual patients. Mean expansion was determined for sinus of Valsalva as 1.93 (95% confidence interval; CI₉₅: 1.87-1.99) mm per decade, and for ascending aorta as 1.76 (CI₉₅: 1.70-1.82) mm per decade. Faster expansion was found in males, with larger aortic size, and younger age (p for interaction <0.05 for all). In conclusion, expansion of the thoracic aorta, in real world, non-syndromic patients, is slow and averages <2 mm per decade. This will help to inform management of this large patient group.

Cardiovascular toxicities of androgen deprivation therapy in Asian men with localized prostate cancer after curative radiotherapy: a registry-based observational study

Background

Androgen deprivation therapy (ADT) and radiotherapy (RT) are the mainstay treatment for localized prostate cancer and recurrence after surgery. Cardiovascular (CV) toxicity of ADT is increasingly recognized, and the risk relates to pre-existing risk factors and ADT modalities. Despite ethnic differences in the prevalence of CV risk factors and variations of CV mortality, data on ADT-related cardiotoxicities in the Asian population remain inconclusive. Our registry-based study investigated ADT-related major adverse cardiovascular events (MACE) after primary or salvage RT.

Methods

Our study combined two prospectively established registry databases from National Cancer Center Singapore and National Heart Center Singapore. The primary endpoint is time to first MACE after treatment. MACE is defined as myocardial infarction, stroke, unstable angina, or cardiovascular death. Two types of propensity score adjustments, including ADT propensity score as a covariate in the multivariable regression model and propensity score weighting, were applied to balance baseline features and CV risk factors between RT alone and RT + ADT groups.

Results

From 2000 to 2019, 1940 patients received either RT alone (n = 494) or RT + ADT (n = 1446) were included. After a median follow-up of 10 years (RT) and 7.2 years (RT+ ADT), the cumulative incidence of MACE at 1, 3 and 9 years was 1.2, 5 and 16.2% in RT group, and 1.1, 5.2 and 17.6% in RT + ADT group, respectively. There were no differences in the incidence of MACE between 2 groups (HR 1.01, 95% CI 0.78–1.30, p = 0.969). Pre-treatment CV risk factors were common (80%), and CV disease (15.9%) was the second leading cause of death after prostate cancer (21.1%). On univariate analysis, older age, Indians and Malays, pre-existing CV risk factors, and history of MACE were associated with higher MACE risk. After propensity score adjustments, there remained no significant differences in MACE risk between RT + ADT and RT group on multivariable analysis.

Conclusions

In our registry-based study, ADT is not associated with increased risk of major cardiovascular events among Southeast Asian men with prostate cancer after curative radiotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40959-022-00131-4.

Gender discrepancy in the predictive effect of aortic root diameter on incidence of cardiovascular events among rural Northeast Chinese

OBJECTIVES

The possible predictive effect of echocardiographic aortic root diameter (ARD) on the incidence of cardiovascular events (CVEs) in a large, general population is limited. In addition, there is a lack of data about rural participants. We intend to figure out the possible relationship between ARD and the incidence of CVEs among the general population from rural China.

DESIGN

Population-based cohort study.

SETTING

Rural areas in Liaoning Province, Northeast China.

PARTICIPANTS

At baseline, 9810 participants (mean age 53±10, 49.1% male) were enrolled in the Northeast China Rural Cardiovascular Health Study between 2012 and 2017.

MAIN OUTCOME MEASURES

Cardiac ultrasonography, lifestyle, medical history, laboratory testing, blood pressure, weight and height. ARD measurement was conducted at the level of the sinuses of Valsalva. Furthermore, the ARD was indexed to height or body surface area.

RESULTS

During a median follow-up of 4.66 years, 550 non-fatal or fatal CVEs were recorded. Adjusting for blood pressure, age, total cholesterol, fasting blood glucose, estimated glomerular filtration rate, current smoking and drinking, previous cardiovascular diseases and antihypertensive treatment; ARD/height (HR per 1-unit increase=1.781, 95% CI: 1.160 to 2.736, p=0.008) was associated with an increased risk of CVEs in men only. The combination of left ventricular hypertrophy (LVH) and aortic dilation was an independent and powerful predictor for cardiovascular prognosis compared with aortic dilation alone in men but not in women.

CONCLUSIONS

Our study enrols a large sample of rural Chinese residents, and first confirms that ARD/height has a predictive effect on the incidence of CVEs among rural Chinese residents. The combination of LVH and aortic dilation is synergistic, which increases its predictive effect on CVEs in men only, suggesting that aortic dilatation predicts cardiovascular prognosis better than LVH does in men but not in women.

A Rare Case Report of Endovascular Therapy for Basilar Artery Occlusion in a Young Adult with Marfan Syndrome

Basilar artery occlusion (BAO) is one of the most devastating types of ischaemic stroke and is identified by using computed tomography (CT) angiography. Marfan syndrome is an autosomal dominant disorder involving multisystem connective tissue, and the neurological complications are relatively rare. In this article, we report a case of a young Marfan syndrome patient complicated with BAO ischaemic stroke. The patient was an 18-year-old man with right hemiparesis, aphasia and impaired consciousness. CT angiography of the brain showed an occlusion distal to the basilar artery. Endovascular therapy including intravenous thrombolysis and mechanical thrombectomy (MT) was administered to this patient inside the therapeutic window. The patient had a favourable clinical outcome after endovascular therapy. Marfan syndrome may be a rare cause of ischaemic stroke with BAO. In addition, our report provides some evidence that can be used as a reference when planning therapeutic strategies for BAO patients with Marfan syndrome.

Predicting premature termination of exercise during Bruce protocol stress echocardiography

AIMS

Clinical guidelines recommend that the exercise protocol of a stress echocardiogram is selected to induce volitional exhaustion after a target duration of at least 8 minutes. While the Bruce protocol is very commonly used for clinical stress tests, it is known to be "steep", and many patients therefore fail to reach 8 minutes. We studied predictors of failure and developed a method for identifying patients not suitable for Bruce protocol which was accurate and yet simple enough to be used as a point-of-care decision support tool.

METHODS AND RESULTS

We studied data out-patients undergoing Bruce protocol stress echocardiograms (n = 11 086) and analyzed predictors of inappropriate early termination (defined as test duration < 8 min as per current practice guidelines) using logistic regression. A prediction model was constructed as follows: .5 points were given for each of hypertension, diabetes, smoking, and E/e' > 7.9 in the resting echocardiogram; .1 point was added for each 1-unit increment in body mass index; 1 point was added for patient age by decade; 2.0 points were subtracted for male sex (p for all < 0.001). In tests on held-out validation data, the model was well calibrated (in plots of predicted vs actual risk) and discriminated failure versus non-failure well (C-statistic .86 for a score of 6.0 points; p < 0.001).

CONCLUSION

These data may help to standardize protocol selection in stress echocardiography, by identifying patients pre-hoc where Bruce protocol will be inappropriately steep.

Noninvasive Cardiac Output and Central Systolic Pressure From Cuff-Pressure and Pulse Wave Velocity

GOAL

We introduce a novel approach to estimate cardiac output (CO) and central systolic blood pressure (cSBP) from noninvasive measurements of peripheral cuff-pressure and carotid-to-femoral pulse wave velocity (cf-PWV).

METHODS

The adjustment of a previously validated one-dimensional arterial tree model is achieved via an optimization process. In the optimization loop, compliance and resistance of the generic arterial tree model as well as aortic flow are adjusted so that simulated brachial systolic and diastolic pressures and cf-PWV converge towards the measured brachial systolic and diastolic pressures and cf-PWV. The process is repeated until full convergence in terms of both brachial pressures and cf-PWV is reached. To assess the accuracy of the proposed framework, we implemented the algorithm on in vivo anonymized data from 20 subjects and compared the method-derived estimates of CO and cSBP to patient-specific measurements obtained with Mobil-O-Graph apparatus (central pressure) and two-dimensional transthoracic echocardiography (aortic blood flow).

RESULTS

Both CO and cSBP estimates were found to be in good agreement with the reference values achieving an RMSE of 0.36 L/min and 2.46 mmHg, respectively. Low biases were reported, namely -0.04 ± 0.36 L/min for CO predictions and -0.27 ± 2.51 mmHg for cSBP predictions.

SIGNIFICANCE

Our one-dimensional model can be successfully "tuned" to partially patient-specific standards by using noninvasive, easily obtained peripheral measurement data. The in vivo evaluation demonstrated that this method can potentially be used to obtain central aortic hemodynamic parameters in a noninvasive and accurate way.

Allometric Relationships for Cardiac Size and Longitudinal Function in Healthy Chinese Adults - Normal Ranges and Clinical Correlates

BACKGROUND

Cardiac size measurements require indexing to body size. Allometric indexing has been investigated in Caucasian populations but a range of different values for the so-called allometric power exponent (b) have been proposed, with uncertainty as to whether allometry offers clinical utility above body surface area (BSA)-based indexing. We derived optimal values for b in normal echocardiograms and validated them externally in cardiac patients.

METHODS AND RESULTS

Values for b were derived in healthy adult Chinese males (n=1,541), with optimal b for left ventricular mass (LVM) of 1.66 (95% confidence interval 1.41-1.92). LV hypertrophy (LVH) defined as indexed LVM >75 g/m^1.66 was associated with adverse outcomes in an external validation cohort (n=738) of patients with acute coronary syndrome (odds ratio for reinfarction: 2.4 (1.1-5.4)). In contrast, LVH defined by BSA-based indexing or allometry using exponent 2.7 exhibited no significant association with outcomes (P=NS for both). Cardiac longitudinal function also varied with body size: septal and RV free wall s', TAPSE and lateral e' all scaled allometrically (b=0.3-0.9).

CONCLUSIONS

An optimal b of 1.66 for LVM in healthy Chinese was found to validate well, with superior clinical utility both to that of BSA-based indexing and to b=2.7. The effect of allometric indexing of cardiac function requires further study.

The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

The mitochondrial calcium uniporter (MCU)-a calcium uniporter on the inner membrane of mitochondria-controls the mitochondrial calcium uptake in normal and abnormal situations. Mitochondrial calcium is essential for the production of adenosine triphosphate (ATP); however, excessive calcium will induce mitochondrial dysfunction. Calcium homeostasis disruption and mitochondrial dysfunction is observed in many neurodegenerative disorders. However, the role and regulatory mechanism of the MCU in the development of these diseases are obscure. In this review, we summarize the role of the MCU in controlling oxidative stress-elevated mitochondrial calcium and its function in neurodegenerative disorders. Inhibition of the MCU signaling pathway might be a new target for the treatment of neurodegenerative disorders.