Relation between diastolic perfusion time and coronary artery stenosis during stress-induced myocardial ischemia

Research Progress and Clinical Value of Subendocardial Viability Ratio

Cardiovascular disease remains the leading cause of morbidity and mortality worldwide, with ischemic heart disease being a major contributor, either through coronary atherosclerotic plaque-related major vascular disease or coronary microvascular dysfunction. Obstruction of coronary blood flow impairs myocardial perfusion, which may lead to acute myocardial infarction in severe cases. The subendocardial viability ratio, also known as the Buckberg index, is a valuable tool for evaluation of myocardial perfusion because it reflects the balance between myocardial oxygen supply and oxygen demand. The subendocardial viability ratio can effectively evaluate the function of the coronary microcirculation and is associated with arterial stiffness. This ratio also has potential value in predicting adverse cardiovascular events and mortality in various populations. Moreover, the subendocardial viability ratio has demonstrated clinical significance in a range of diseases, including hypertension, aortic stenosis, peripheral arterial disease, chronic kidney disease, diabetes, and rheumatoid arthritis. This review summarizes the applications of the subendocardial viability ratio, its particular progress in the relevant research, and its clinical significance in cardiovascular diseases.

Class of hemorrhagic shock is associated with progressive diastolic coronary flow reversal and diminished left ventricular function

Introduction: The relationship between coronary artery flow and left ventricular (LV) function during hemorrhagic shock remains unknown. The aim of this study was to quantify coronary artery flow directionality alongside left ventricular function through the four classes of hemorrhage shock. Methods: Following baseline data collection, swine were exsanguinated into cardiac arrest via the femoral artery using a logarithmic bleed, taking each animal through the four classes of hemorrhagic shock based on percent bleed (class I: 15%; class II: 15%-30%; class III: 30%-40%; class IV: >40%). Telemetry data, left ventricular pressure-volume loops, and left anterior descending artery flow tracings over numerous cardiac cycles were collected and analyzed for each animal throughout. Results: Five male swine (mean 72 ± 12 kg) were successfully exsanguinated into cardiac arrest. Mean left ventricular end-diastolic volume, end-diastolic pressure, and stroke work decreased as the hemorrhagic shock class progressed (p < 0.001). The proportion of diastole spent with retrograde coronary flow was also associated with class of hemorrhagic shock (mean 5.6% of diastole in baseline, to 63.9% of diastole in class IV; p < 0.0001), worsening at each class from baseline through class IV. Preload recruitable stroke work (PRSW) decreased significantly in classes II through IV (p < 0.001). Systemic Vascular Resistance (SVR) is associated with class of hemorrhage shock (p < 0.001). Conclusion: With progressive classes of hemorrhagic shock left ventricular function progressively decreased, and the coronary arteries spent a greater proportion of diastole in retrograde flow, with progressively more negative total coronary flow. Preload recruitable stroke work, a load-independent measure of inotropy, also worsened in severe hemorrhagic shock, indicating the mechanism extends beyond the drop in preload and afterload alone.

Outcomes of Hospitalizations With Septic Shock Complicated by Types 1 and 2 Myocardial Infarction

Septic shock is a life-threatening host response to infection and a significant contributor to cost burden in the United States. Furthermore, sepsis-related inflammation has been linked to myocardial infarction (MI). We sought to examine the association of type 1 and type 2 MI with outcomes in hospitalizations admitted with septic shock. The National Readmission Database 2018 was queried to identify hospitalizations with hospital discharge diagnoses of septic shock without MI, septic shock with type 1 MI, or septic shock with type 2 MI. Complex-sample multivariable logistic and linear regression models were used to determine the association of these conditions with clinical outcomes. Of 354,528 hospitalizations with septic shock, 11,519 had type 1 MI (3.2%) and 13,970 had type 2 MI (3.9%). Compared with septic shock without MI, type 1 MI was associated with higher mortality (adjusted odds ratio [OR] 1.67, 95% confidence interval [CI] 1.57 to 1.77), costs (adjusted parameter estimate $4,571, 95% CI 3,020 to 6,122), and discharge to facility (adjusted OR 1.09, 95% CI 1.01 to 1.17). In contrast, septic shock with type 2 MI was associated with similar mortality and discharge to nursing facility and higher costs (adjusted parameter estimate 1,798, 95% CI 549 to 3,047). Septic shock hospitalizations with type 1 MI had higher in-hospital mortality (adjusted OR 1.74, 95% CI 1.60 to 1.90, p <0.001) compared with type 2 MI. In conclusion, type 1 MI is associated with higher mortality and resource utilization among septic shock hospitalizations. Furthermore, type 2 MI was associated with higher resource utilization.

Challenges in Diagnosis and Functional Assessment of Coronary Artery Disease in Patients With Severe Aortic Stenosis

More than half of patients with severe aortic stenosis (AS) over 70 years old have coronary artery disease (CAD). Exertional angina is often present in AS-patients, even in the absence of significant CAD, as a result of oxygen supply/demand mismatch and exercise-induced myocardial ischemia. Moreover, persistent myocardial ischemia leads to extensive myocardial fibrosis and subsequent coronary microvascular dysfunction (CMD) which is defined as reduced coronary vasodilatory capacity below ischemic threshold. Therefore, angina, as well as noninvasive stress tests, have a low specificity and positive predictive value (PPV) for the assessment of epicardial coronary stenosis severity in AS-patients. Moreover, in symptomatic patients with severe AS exercise testing is even contraindicated. Given the limitations of noninvasive stress tests, coronary angiography remains the standard examination for determining the presence and severity of CAD in AS-patients, although angiography alone has poor accuracy in the evaluation of its functional severity. To overcome this limitation, the well-established invasive indices for the assessment of coronary stenosis severity, such as fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), are now in focus, especially in the contemporary era with the rapid increment of transcatheter aortic valve replacement (TAVR) for the treatment of AS-patients. TAVR induces an immediate decrease in hyperemic microcirculatory resistance and a concomitant increase in hyperemic flow velocity, whereas resting coronary hemodynamics remain unaltered. These findings suggest that FFR may underestimate coronary stenosis severity in AS-patients, whereas iFR as the non-hyperemic index is independent of the AS severity. However, because resting coronary hemodynamics do not improve immediately after TAVR, the coronary vasodilatory capacity in AS-patients treated by TAVR remain impaired, and thus the iFR may overestimate coronary stenosis severity in these patients. The optimal method for evaluating myocardial ischemia in patients with AS and co-existing CAD has not yet been fully established, and this important issue is under further investigation. This review is focused on challenges, limitations, and future perspectives in the functional assessment of coronary stenosis severity in these patients, bearing in mind the complexity of coronary physiology in the presence of this valvular heart disease.

miR-124 promotes apoptosis and inhibits the proliferation of vessel endothelial cells through P38/MAPK and PI3K/AKT pathways, making it a potential mechanism of vessel endothelial injury in acute myocardial infarction

Due to its rapid onset and high rates of fatality, acute myocardial infarction (AMI) has long been one of the most fatal diseases among all types of heart diseases. Therefore, intensive research efforts have been focused on understanding AMI's potential pathogenesis to seek effective treatment options. In the present study, 20 peripheral blood samples were collected from patients with AMI, after which reverse transcription-quantitative PCR analysis revealed that microRNA (miR)-124 levels in the peripheral blood of patients with AMI was significantly elevated compared with that in the control group. In vitro, a model using pcDNA3.1-miR-124 transfected human umbilical vein endothelial cells (HUVECs) indicated that overexpression of miR-124 could significantly promote the apoptosis and suppress the proliferation of HUVECs using flow cytometry, TUNEL assay and Cell Counting Kit-8 assays. Based on the present findings, RNA samples of HUVECs overexpressing miR-124 was extracted and sequenced to explore the gene expression profile after miR-124 overexpression. Gene Set Enrichment Analysis (GSEA) analysis revealed that the downregulated genes were mainly enriched in signaling pathways, such as PI3K-AKT, whilst the upregulated genes were mainly enriched in metabolism-related signaling pathways, such as the metabolism of xenobiotics by cytochrome P450 pathway. Additionally, Rideogram software was used to determine the chromosomal localization of the differentially expressed genes. The results demonstrated that they were distributed on all chromosomes except for chromosome Y. In addition, characteristic profiles of the differentially expressed genes caused by miR-124 overexpression were analyzed using Connectivity Map. In total, two medicines, anisomycin and sanguinarine, which function as p38/MAPK signaling agonists that can inhibit angiogenesis, presented with the highest enrichment scores. Together with the GSEA results, which indicated that the differentially expressed genes were mainly enriched in the angiogenesis-inhibiting PI3K/AKT signaling pathway, the present study reported that high expression of miR-124 was negatively associated with patients with AMI, promoting the apoptosis and suppressing the proliferation of vessel endothelial cells.

Involvement of cardiovascular system as the critical point in coronavirus disease 2019 (COVID-19) prognosis and recovery

The novel coronavirus disease 2019 (COVID-19) pandemic has already caused more than 300,000 deaths worldwide. Several studies have elucidated the central role of cardiovascular complications in the disease course. Herein, we provide a concise review of current knowledge regarding the involvement of cardiovascular system in the pathogenesis and prognosis of COVID-19. We summarize data from 21 studies involving in total more than 21,000 patients from Asia, Europe, and the USA indicating that severe disease is associated with the presence of myocardial injury, heart failure, and arrhythmias. Additionally, we present the clinical and laboratory differences between recovered and deceased patients highlighting the importance of cardiac manifestations. For the infected patients, underlying cardiovascular comorbidities and particularly existing cardiovascular disease seem to predispose to the development of cardiovascular complications, which are in turn associated with higher mortality rates. We provide mechanistic insights into the underlying mechanisms including direct myocardial damage by the virus and the consequences of the hyperinflammatory syndrome developed later in the disease course. Finally, we summarize current knowledge on therapeutic modalities and recommendations by scientific societies and experts regarding the cardiovascular management of patients with COVID-19.

Predictors of adverse prognosis in COVID-19: A systematic review and meta-analysis

BACKGROUND

Identification of reliable outcome predictors in coronavirus disease 2019 (COVID-19) is of paramount importance for improving patient's management.

METHODS

A systematic review of literature was conducted until 24 April 2020. From 6843 articles, 49 studies were selected for a pooled assessment; cumulative statistics for age and sex were retrieved in 587 790 and 602 234 cases. Two endpoints were defined: (a) a composite outcome including death, severe presentation, hospitalization in the intensive care unit (ICU) and/or mechanical ventilation; and (b) in-hospital mortality. We extracted numeric data on patients' characteristics and cases with adverse outcomes and employed inverse variance random-effects models to derive pooled estimates.

RESULTS

We identified 18 and 12 factors associated with the composite endpoint and death, respectively. Among those, a history of CVD (odds ratio (OR) = 3.15, 95% confidence intervals (CIs) 2.26-4.41), acute cardiac (OR = 10.58, 5.00-22.40) or kidney (OR = 5.13, 1.78-14.83) injury, increased procalcitonin (OR = 4.8, 2.034-11.31) or D-dimer (OR = 3.7, 1.74-7.89), and thrombocytopenia (OR = 6.23, 1.031-37.67) conveyed the highest odds for the adverse composite endpoint. Advanced age, male sex, cardiovascular comorbidities, acute cardiac or kidney injury, lymphocytopenia and D-dimer conferred an increased risk of in-hospital death. With respect to the treatment of the acute phase, therapy with steroids was associated with the adverse composite endpoint (OR = 3.61, 95% CI 1.934-6.73), but not with mortality.

CONCLUSIONS

Advanced age, comorbidities, abnormal inflammatory and organ injury circulating biomarkers captured patients with an adverse clinical outcome. Clinical history and laboratory profile may then help identify patients with a higher risk of in-hospital mortality.

Cardiovascular Manifestations of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the cause of COVID-19, was first reported in Wuhan, China. SARS-CoV-2 especially involves alveolar epithelial cells, which results in respiratory symptoms more severe in patients with cardiovascular disease (CVD) probably linked with increased secretion of angiotensin-converting enzyme 2 in these patients compared with healthy individuals. Cardiac manifestations may contribute to overall mortality and even be the primary cause of death in many of these patients. A higher prevalence of hypertension (HTN) followed by diabetes mellitus and CVD was observed in COVID-19 patients. A higher case-fatality rate was seen among patients with pre-existing comorbid conditions, such as diabetes, chronic respiratory disease, HTN, and cancer, compared to a lesser rate in the entire population. Cardiovascular (CV) manifestations of COVID-19 encompass a wide spectrum, including myocardial injury, infarction, myocarditis-simulating ST-segment elevation myocardial infarction, nonischemic cardiomyopathy, coronary vasospasm, pericarditis, or stress (takotsubo) cardiomyopathy. This review is intended to summarize our current understanding of the CV manifestations of COVID-19 and also to study the relationship between SARS-CoV-2 and CVDs and discuss possible mechanisms of action behind SARS-CoV-2 infection-induced damage to the CV system.

Changes of the coronary arteries and cardiac microvasculature with aging: Implications for translational research and clinical practice

Aging results in functional and structural changes in the cardiovascular system, translating into a progressive increase of mechanical vessel stiffness, due to a combination of changes in micro-RNA expression patterns, autophagy, arterial calcification, smooth muscle cell migration and proliferation. The two pivotal mechanisms of aging-related endothelial dysfunction are oxidative stress and inflammation, even in the absence of clinical disease. A comprehensive understanding of the aging process is emerging as a primary concern in literature, as vascular aging has recently become a target for prevention and treatment of cardiovascular disease. Change of life-style, diet, antioxidant regimens, anti-inflammatory treatments, senolytic drugs counteract the pro-aging pathways or target senescent cells modulating their detrimental effects. Such therapies aim to reduce the ineluctable burden of age and contrast aging-associated cardiovascular dysfunction. This narrative review intends to summarize the macrovascular and microvascular changes related with aging, as a better understanding of the pathways leading to arterial aging may contribute to design new mechanism-based therapeutic approaches to attenuate the features of vascular senescence and its clinical impact on the cardiovascular system.

Reintroducing Heart Sounds for Early Detection of Acute Myocardial Ischemia in a Porcine Model - Correlation of Acoustic Cardiography With Gold Standard of Pressure-Volume Analysis

Background

Acoustic cardiography is a hybrid technique that couples heart sounds recording with ECG providing insights into electrical-mechanical activity of the heart in an unsupervised, non-invasive and inexpensive manner. During myocardial ischemia hemodynamic abnormalities appear in the first minutes and we hypothesize a putative diagnostic role of acoustic cardiography for prompt detection of cardiac dysfunction for future patient management improvement.

Methods and Results

Ten female Swiss large white pigs underwent permanent distal coronary occlusion as a model of acute myocardial ischemia. Acoustic cardiography analyses were performed prior, during and after coronary occlusion. Pressure-volume analysis was conducted in parallel as an invasive method of hemodynamic assessment for comparison. Similar systolic and diastolic intervals obtained with the two techniques were significantly correlated [Q to min dP/dt vs. Q to second heart sound (r² = 0.9583, p < 0.0001), PV diastolic filling time vs. AC perfusion time (r² = 0.9686, p < 0.0001)]. Indexes of systolic and diastolic impairment correlated with quantifiable features of heart sounds [Tau vs. fourth heart sound Display Value (r² = 0.2721, p < 0.0001) cardiac output vs. third heart sound Display Value (r² = 0.0791 p = 0.0023)]. Additionally, acoustic cardiography diastolic time (AUC 0.675, p = 0.008), perfusion time (AUC 0.649, p = 0.024) and third heart sound Display Value (AUC 0.654, p = 0.019) emerged as possible indicators of coronary occlusion. Finally, these three parameters, when joined with heart rate into a composite joint-index, represent the best model in our experience for ischemia detection (AUC 0.770, p < 0.001).

Conclusion

In the rapidly evolving setting of acute myocardial ischemia, acoustic cardiography provided meaningful insights of mechanical dysfunction in a prompt and non-invasive manner. These findings should propel interest in resurrecting this technique for future translational studies as well as reconsidering its reintroduction in the clinical setting.

Arterial aging: pathophysiological principles

In the nineteenth century, prior to the introduction of the cuff sphygmomanometer, arteriosclerosis (stiffening of arteries) was recognized by clinicians and by life insurance companies as an indicator of vascular aging and cardiovascular risk, even in asymptomatic individuals. Through the twentieth century, views on aging came to focus on values of systolic and diastolic pressure and on obstructive atherosclerotic disease. Such focus deflected attention from the primary aging change which occurs in all societies, and is represented by stiffening and dilation of the proximal aorta. This review emphasizes the cushioning function of elastic arteries — principally the aorta — and how in youth this results in optimal interaction with the heart, and optimal steady flow through peripheral resistance vessels. Aortic stiffening with age is principally due to fatigue and fracture of elastin lamellae, with transfer of stress to stiffer collagenous components. Stiffening increases left ventricular load and myocardial blood requirement, but limits the capacity for blood supply during diastole. Consequences are cardiac failure and predisposition to ischaemia. The second, under-appreciated effect of aortic stiffening is transmission of flow pulsations downstream into vasodilated organs, principally brain and kidney, where pulsatile energy is dissipated and fragile microvessels are damaged. This accounts for micro infarcts and microhaemorrhages, with specialized cell damage, cognitive decline and renal failure. The aging process can be best monitored by change in the arterial pressure wave rather than by reliance on the cuff sphygmomanometer. This reintroduces the approaches by clinicians and life insurance examiners of the nineteenth century, endorses modern treatments for established disease, and holds the promise of detecting premature arterial degeneration, and better applying lifestyle measures and vasoactive medications to modify the aging process.

Baseline subendocardial viability ratio influences left ventricular systolic improvement with cardiac rehabilitation

OBJECTIVE

Subendocardial viability ratio (SEVR), defined as diastolic to systolic pressure-time integral ratio, is a useful tool reflecting the balance between coronary perfusion and arterial load. Suboptimal SEVR creating a supply-demand imbalance may limit favorable cardiac response to cardiac rehabilitation (CR). To explore this hypothesis, we designed a study to analyze the relationship between baseline SEVR and response to CR in patients with coronary artery disease (CAD).

METHODS

In this prospectively study, after baseline arterial tonometry, echocardiography, and cardiopulmonary exercise tests (CPETs), patients undergone 20 sessions of CR. Post-CR echocardiographic and CPET measurements were obtained for comparison.

RESULTS

Final study population was comprised of fifty subjects. Study population was divided into two subgroups by median SEVR value (1.45, interquartile range 0.38). Although both groups showed significant improvements in peak VO2, significant improvements in oxygen pulse (πO2) (from 16.1±3.4 to 19.1±4.8 mL O2.kg-1.beat-1; p<0.001) and stroke volume index (from 31±5 to 35±6 mL; p=0.008) were observed in only the patients in the above-median subgroup. The change in πO2 was also significantly higher in the above-median SEVR subgroup (2.9±3.3 vs. 0.5±2.4; p=0.007).

CONCLUSION

Our study shows that baseline supply-demand imbalance may limit systolic improvement response to CR in patients with CAD.

Association of aortic stiffness and wave reflections with coronary flow reserve in women without obstructive coronary artery disease: An ancillary study from the National Heart, Lung, and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

Increased aortic stiffness and reduced coronary flow reserve (CFR) independently predict adverse outcomes. But information about relationships between arterial properties and CFR in subjects without obstructive coronary artery disease (CAD) is limited.

METHODS

CFR was measured (Doppler flow wire and intracoronary adenosine) in 50 women (age 53 ± 11 years) with symptoms and signs of myocardial ischemia without obstructive CAD. Aortic pulse wave velocity (aPWV), a measure of aortic stiffness, was obtained via catheter pullback; radial artery pressure waves were measured by applanation tonometry and central aortic pressure synthesized.

RESULTS

Overall, CFR (mean 2.61 ± 0.47) was significantly correlated with aPWV (r = -0.51), pulse wave amplification (r = 0.45), augmented pressure (r = -0.48), augmentation index (AIx, r = -0.44), aortic systolic pressure (r = -0.49), left ventricular wasted energy (LVEw, r = -0.47) (all P < .001), systolic pressure time index (r = -0.37, P < .008), and rate pressure product (r = -0.29, P < .04). In the multiple regression model including aPWV, CFR was still significantly correlated with aPWV (P < .008) and aortic systolic pressure (P < .01). No other measures contributed significant additional information. Women with CFR ≤2.5 versus those with CFR >2.5 had greater aPWV (894 ± 117 vs 747 ± 93 cm/s, P < .001), augmented pressure (14 ± 4.9 vs 11 ± 4.1 mmHg, P < .008), AIx (32 ± 6.6 vs 27 ± 6.6%, P < .003), LVEw (30 ± 12 vs 21 ± 10 dyne-s/cm(2) × 10(2), P < .02) and reduced pulse pressure amplification (1.20 ± .07 vs 1.26 ± .10, P < .008) and pressure wave travel time (133 ± 7.3 vs 138 ± 6.9 milliseconds, P < .04).

CONCLUSIONS

Among symptomatic women without obstructive CAD, CFR was inversely related to aortic systolic pressure and indices of aortic stiffness. These changes in arterial properties increase left ventricular afterload requiring the ventricle to generate additional, but wasted, energy that increases indices of myocardial oxygen demand, reduces CFR and increases vulnerability to ischemia.

Cardiac and Hemodynamic Benefits: Mode of Action of Ivabradine in Heart Failure

Heart failure has seen a number of therapeutic advances in recent years. Despite this, heart failure is still related to increasing rates of morbidity, repeated hospitalizations, and mortality. Ivabradine is a recent treatment option for heart failure. It has a mode of action that includes reduction in heart rate, and leads to improvement in outcomes related to heart failure mortality and morbidity, as demonstrated by the results of the SHIFT trial in patients with systolic heart failure, functional classes II and III on the New York Heart Association classification, and left ventricular ejection fraction ≤ 35%. These results are intriguing since many heart failure drugs reduce heart rate without such benefits, or with quite different effects, making it more difficult to understand the novelty of ivabradine in this setting. Many of the drugs used in heart failure modify heart rate, but most have other pathophysiological effects beyond their chronotropic action, which affect their efficacy in preventing morbidity and mortality outcomes. For instance, heart rate reduction at rest or exercise with ivabradine prolongs diastolic perfusion time, improves coronary blood flow, and increases exercise capacity. Another major difference is the increase in stroke volume observed with ivabradine, which may underlie its beneficial cardiac effects. Finally, there is mounting evidence from both preclinical and clinical studies that ivabradine has an anti-remodeling effect, improving left ventricular structures and functions. All together, these mechanisms have a positive impact on the prognosis of ivabradine-treated patients with heart failure, making a compelling argument for use of ivabradine in combination with other treatments.

High Order Statistics and Time-Frequency Domain to Classify Heart Sounds for Subjects under Cardiac Stress Test

This paper considers the problem of classification of the first and the second heart sounds (S1 and S2) under cardiac stress test. The main objective is to classify these sounds without electrocardiogram (ECG) reference and without taking into consideration the systolic and the diastolic time intervals criterion which can become problematic and useless in several real life settings as severe tachycardia and tachyarrhythmia or in the case of subjects being under cardiac stress activity. First, the heart sounds are segmented by using a modified time-frequency based envelope. Then, to distinguish between the first and the second heart sounds, new features, named α_opt, β, and γ, based on high order statistics and energy concentration measures of the Stockwell transform (S-transform) are proposed in this study. A study of the variation of the high frequency content of S1 and S2 over the HR (heart rate) is also discussed. The proposed features are validated on a database that contains 2636 S1 and S2 sounds corresponding to 62 heart signals and 8 subjects under cardiac stress test collected from healthy subjects. Results and comparisons with existing methods in the literature show a large superiority for our proposed features.

Vascular and central hemodynamic changes following exercise-induced heat stress

This study examined the effects of moderate exercise-induced heat stress (EIHS) on vascular function, central hemodynamic load and indices of coronary perfusion. Vascular-hemodynamic measures were collected in 12 healthy men (aged 22±3 years) pre and post 100 minutes of moderate, intermittent exercise in two randomized conditions: heat stress (HS; wearing firefighter personal protective equipment (PPE)), and no heat stress (NHS; wearing a cooling shirt and equivalent PPE weight). Aortic blood pressure, reflected wave pressure (Pb), systolic (SPTI) and diastolic pressure time-integral (DPTI), and aortic stiffness were assessed before and after each condition. SPTI was significantly greater, and DPTI and Pb were significantly lower for HS-post compared to NHS-post (p<0.05). Pulse wave velocity was not different between conditions. In conclusion, EIHS does not affect aortic stiffness, but increases indices of myocardial work and reduces indices of coronary perfusion which may be related to chronotropic responses to EIHS. The mismatch between oxygen demand and oxygen supply may increase cardiac vulnerability to ischemia during strenuous work in the heat.

Walking speed and high blood pressure mortality risk in a Spanish elderly population

This study analyzed the relationship between blood pressure and all-cause mortality according to objectively measured walking speed in a Mediterranean population-based sample of older persons. We used data from the longitudinal 'Peñagrande' Cohort Study, initiated in 2008 in a sex- and age-stratified random sample of 1250 people aged ⩾65 years living in Madrid (Spain). A total of 814 individuals participated in the first study wave. The average of two standardized blood pressure readings was used. Walking speed was measured over a 3-m walk and classified as faster (⩾0.8 m s(-1)) or slower. A total of 314 individuals were slower walkers, 475 were faster walkers and 25 did not complete the walk test. Cox proportional hazards models stratified by walking speed were used to assess the association between blood pressure and all-cause death. Non-linear relationship between BP and mortality was explored by a restricted cubic spline analysis. There were 171 deaths from study entry through 31 March 2013. Systolic blood pressure <140 mm Hg and diastolic blood pressure <90 mmHg were associated with higher mortality than blood pressure values above 140 and 90 mm Hg, respectively, but this association reached statistical significance only for systolic blood pressure and only in the slower walkers. In conclusion, systolic blood pressure levels <140 mm Hg were found associated with higher risk of total mortality among slower walkers in an old Spaniard population cohort.

Effect of CPAP on arterial stiffness in severely obese patients with obstructive sleep apnoea

BACKGROUND

Obstructive sleep apnoea (OSA) may independently increase cardiovascular risk in obesity. Although there is evidence that arterial stiffness is altered in OSA, knowledge of these effects with continuous positive airway pressure (CPAP) in severe obesity (body mass index (BMI) ≥ 35 kg/m(2)) is limited. This study aimed to explore how arterial stiffness, as measured by the augmentation index (Aix), changed in severely obese patients with OSA who were treated with CPAP and in patients without OSA.

METHODS

Forty-two patients with severe obesity-22 with OSA, 20 without OSA-were recruited at baseline and followed-up after a median of 13.5 months. Pulse wave analysis (PWA) was performed using applanation tonometry at the radial artery to measure augmentation index (Aix), augmentation pressure (AP) and subendocardial viability ratio (SEVR). Cardiovascular parameters and body composition were also measured.

RESULTS

There were significant improvements in Aix, AP (both P < 0.001) and SEVR (P = 0.021) in OSA patients on CPAP compared with subjects without OSA. Epworth scores (P < 0.001), systolic (P < 0.001) and mean arterial pressures (P = 0.002) improved with CPAP. Regression showed that CPAP was significantly associated with change in arterial stiffness from baseline. However, patients with OSA on CPAP continued to have increased arterial stiffness (Aix) (P < 0.001), AP (P = 0.028) and reduced SEVR (P = 0.002) relative to non-OSA patients.

CONCLUSION

Although sleepiness and blood pressure improve with CPAP in severe obesity, CPAP alone is not sufficient to modify PWA measures to levels comparable with non-OSA patients. This supports a need for a multifaceted approach when managing cardiovascular risk in patients with severe obesity and obstructive sleep apnoea receiving CPAP therapy.

The instantaneous wave-free ratio (iFR) for evaluation of non-culprit lesions in patients with acute coronary syndrome and multivessel disease

BACKGROUND

Adenosine administration is currently required for evaluation of stenosis severity with fractional flow reserve (FFR). The instantaneous wave-free ratio (iFR) was recently introduced as an adenosine-free alternative in patients with stable CAD. The aim of the present study was to replicate the findings of previous iFR studies using an independent calculation algorithm and to evaluate the iFR for the assessment of non-culprit vessels in patients with acute coronary syndrome (ACS).

METHODS AND RESULTS

53 patients with ACS (65%) and at least one non-culprit intermediate lesion and 29 (35%) with stable CAD were included. A total of 123 stenoses were evaluated with both FFR and iFR. Classification match of iFR in ACS was not inferior to stable CAD (79.5% in ACS and 84.4% in CAD; p=0.497). Accordingly, no difference was observed in iFR/FFR correlation between ACS and stable CAD (r=0.66 in ACS vs. r=0.69 in CAD). Overall, a significant correlation was found between iFR and FFR (r=0.68; p<0.001) with a good diagnostic efficiency at ROC analysis (area under the curve: 0.87). In addition, neither the localization of the stenosis within the coronary tree (p=0.147) nor the time interval from the acute event (p=0.550) significantly influenced the concordance of iFR with FFR.

CONCLUSIONS

The iFR is a promising method for the assessment of non-culprit lesion severity in patients with acute coronary syndrome.

Effect of the arteriovenous access for hemodialysis on subendocardial viability ratio, pulse pressure and hospitalizations

BACKGROUND

In some patients the potential benefits of the arteriovenous (AV) access over catheter for hemodialysis seem to be outweighed by global cardiovascular status deterioration.

METHODS

We prospectively evaluated 44 pre-dialysis chronic kidney disease patients submitted to vascular access creation during a follow-up of 25 ± 9 months. We performed pulse wave analysis and biochemical assessment before and 2 months after AV access construction, and we registered premature vascular access thrombosis, and all-cause and cardiovascular hospitalizations throughout follow-up.

RESULTS

We found a statistically significant decrease in the subendocardial viability ratio (SEVR) and pulse pressure (PP) parameters after AV access creation while brain natriuretic peptide significantly increased. Receiver operating characteristic curve analysis identified SEVR ≤113 % evaluated 2 months after vascular access construction as the best cutoff value for predicting all-cause and cardiovascular hospitalizations. Kaplan-Meier analysis showed that a SEVR ≤113 % was associated with all-cause (p = 0.010) and cardiovascular (p = 0.029) hospitalizations; Cox regression analysis verified a 4.9-fold higher risk of all-cause hospitalization in patients with SEVR ≤113 % (p = 0.005).

CONCLUSION

To our best knowledge, this report indicates, for the first time, that despite the decrease in PP parameters, the creation of a vascular access for hemodialysis was also associated with a reduction of SEVR which predicted a worse clinical outcome. We argue that the decrease of pulse pressure after arteriovenous construction may reflect a new hemodynamic set-point after vascular access creation and may not indicate a protective cardiovascular effect.

Increased wave reflection and ejection duration in women with chest pain and nonobstructive coronary artery disease: ancillary study from the Women's Ischemia Syndrome Evaluation

OBJECTIVE

Wave reflections augment central aortic SBP and increase systolic pressure time integral (SPTI) thereby increasing left ventricular (LV) afterload and myocardial oxygen (MVO2) demand. When increased, such changes may contribute to myocardial ischemia and angina pectoris, especially when aortic diastolic time is decreased and myocardial perfusion pressure jeopardized. Accordingly, we examined pulse wave reflection characteristics and diastolic timing in a subgroup of women with chest pain (Women's Ischemia Syndrome Evaluation, WISE) and no obstructive coronary artery disease (CAD).

METHODS

Radial artery BP waveforms were recorded by applanation tonometry, and aortic BP waveforms derived. Data from WISE participants were compared with data from asymptomatic women (reference group) without chest pain matched for age, height, BMI, mean arterial BP, and heart rate.

RESULTS

Compared with the reference group, WISE participants had higher aortic SBP and pulse BP and ejection duration. These differences were associated with increased augmentation index and reflected pressure wave systolic duration. These modifications in wave reflection characteristics were associated with increased SPTI and wasted LV energy (Ew) and a decrease in pulse pressure amplification, myocardial viability ratio, and diastolic pressure time fraction.

CONCLUSION

WISE participants with no obstructive CAD have changes in systolic wave reflections and diastolic timing that increase LV afterload, MVO2 demand, and Ew with the potential to reduce coronary artery perfusion. These alterations in cardiovascular function contribute to an undesirable mismatch in the MVO2 supply/demand that promotes ischemia and chest pain and may contribute to, or increase the severity of, future adverse cardiovascular events.

Myocardial perfusion and the J curve association between diastolic blood pressure and mortality

BACKGROUND

The J-curve relationship between brachial diastolic blood pressure (DBP) and mortality is believed to be mediated through reduced myocardial perfusion. This study aimed to determine the relationship between DBP and subendocardial perfusion in patients with and without coronary artery disease (CAD) and to examine central hemodynamic variables that may explain the risk associated with low DBP (aortic stiffness, central pulse pressure, and augmentation index).

METHODS

Brachial DBP and radial tonometry were measured in 134 patients with CAD (aged 76±7years; 69% male), 134 individuals without a prior cardiovascular event (control subjects) (aged 77±2years; 69% male) and 47 patients (aged 63±10years) during dobutamine stress echocardiography. Central hemodynamics and subendocardial viability ratio (SEVR), a marker of subendocardial perfusion, were recorded by tonometry.

RESULTS

There was no difference in DBP or SEVR between control subjects and CAD patients (P > 0.05), nor was there a difference in SEVR across quartiles of DBP in CAD patients (P = 0.07) or control subjects (P = 0.14). After adjustment for age and height, associations between DBP and SEVR in control subjects (r = 0.185; P = 0.03) and CAD patients (r = 0.204; P = 0.02) were attenuated (P = 0.07 and P = 0.11, respectively). There were no significant relationships between DBP and central hemodynamics (P > 0.05 for all). At peak dobutamine stress, SEVR was significantly reduced in patients with inducible ischemia vs. those with nonischemic response (84±17 vs. 101±22%; P = 0.01). However, DBP was not significantly different (65±14 vs. 67±15mm Hg; P = 0.32).

CONCLUSIONS

Brachial DBP is a poor marker of subendocardial perfusion. The J-curve relationship between DBP and mortality is unlikely attributable to reduced myocardial perfusion or adverse central hemodynamics.

Association between blood pressure and mortality in a Spanish cohort of persons aged 65 years or over: a dynamic model

INTRODUCTION AND OBJECTIVES

Few studies have used time-dependent correction to analyze the relationship between blood pressure and all-cause mortality, and to our knowledge none has been performed in older people from the Mediterranean area. This study aimed to estimate the relationship between baseline blood pressure and blood pressure as a time-dependent covariate with the risk of all-cause mortality in a population cohort of persons aged 65 or older in Spain.

METHODS

Data were taken from the population-based study "Aging in Leganés" with 17 years of follow-up, launched in 1993 in a random sample (n=1560) of persons aged ≥65 years. Mortality was assessed in 2010. Cox proportional hazards models were fitted to examine the effects on mortality of blood pressure at baseline and of blood pressure as a time-dependent covariate.

RESULTS

The lowest mortality was observed at baseline systolic blood pressure of 136 mmHg and time-dependent covariate value of 147 mmHg. The highest risk of mortality for time-dependent covariates occurred with systolic blood pressure <115 mmHg and >93 mmHg and diastolic blood pressure <80 mmHg. Diastolic blood pressure over 85 mmHg did not increase the risk of death.

CONCLUSIONS

Based on the dynamic association between blood pressure and mortality, a U-shaped relationship was found for systolic blood pressure and a negative relationship for diastolic blood pressure and all-cause mortality. The lowest mortality corresponded to a systolic blood pressure level slightly over the diagnostic hypertension value and suggests that a value of 140 mmHg is not adequate as a diagnostic and therapeutic threshold in an elderly population.

Changes in subendocardial viability ratio with acute high-altitude exposure and protective role of acetazolamide

High-altitude tourism is increasingly frequent, involving also subjects with manifest or subclinical coronary artery disease. Little is known, however, on the effects of altitude exposure on factors affecting coronary perfusion. The aim of our study was to assess myocardial oxygen supply/demand ratio in healthy subjects during acute exposure at high altitude and to evaluate the effect of acetazolamide on this parameter. Forty-four subjects (21 men, age range: 24-59 years) were randomized to double-blind acetazolamide 250 mg bid or placebo. Subendocardial viability ratio and oxygen supply/demand ratio were estimated on carotid artery by means of a validated PulsePen tonometer, at sea level, before and after treatment, and after acute and more prolonged exposure to high altitude (4559 m). On arrival at high altitude, subendocardial viability ratio was reduced in both placebo (from 1.63±0.15 to 1.18±0.17; P<0.001) and acetazolamide (from 1.68±0.25 to 1.35±0.18; P<0.001) groups. Subendocardial viability ratio returned to sea level values (1.65±0.24) after 3 days at high altitude under acetazolamide but remained lower than at sea level under placebo (1.42±0.22; P<0.005 versus baseline). At high altitude, oxygen supply/demand ratio fell both under placebo (from 29.6±4.0 to 17.3±3.0; P<0.001) and acetazolamide (from 32.1±7.0 to 22.3±4.6; P<0.001), its values remaining always higher (P<0.001) on acetazolamide. Administration of acetazolamide may, thus, antagonize the reduction in subendocardial oxygen supply triggered by exposure to hypobaric hypoxia. Further studies involving also subjects with known or subclinical coronary artery disease are needed to confirm a protective action of acetazolamide on myocardial viability under high-altitude exposure.

The role of inflammation, the autonomic nervous system and classical cardiovascular disease risk factors on subendocardial viability ratio in patients with RA: a cross-sectional and longitudinal study

INTRODUCTION

Evidence indicates that rheumatoid arthritis (RA) patients have increased susceptibility to myocardial ischaemia that contributes to myocardial infarction. The subendocardial viability ratio (SEVR) can be measured using pulse wave analysis and reflects myocardial oxygen supply and demand. The objective of the present study was to examine specific predictors of SEVR in RA patients, with a specific focus on inflammation and classical cardiovascular disease (CVD) risk factors.

METHODS

Two patient cohorts were included in the study; a primary cohort consisting of 220 RA patients and a validation cohort of 127 RA patients. All patients underwent assessment of SEVR using pulse wave analysis. Thirty-one patients from the primary cohort who were about to start anti-inflammatory treatment were prospectively examined for SEVR at pretreatment baseline and 2 weeks, 3 months and 1 year following treatment. Systemic markers of disease activity and classical CVD risk factors were assessed in all patients.

RESULTS

The SEVR (mean ± standard deviation) for RA in the primary cohort was 148 ± 27 and in the validation cohort was 142 ± 25. Regression analyses revealed that all parameters of RA disease activity were associated with SEVR, along with gender, blood pressure and heart rate. These findings were the same in the validation cohort. Analysis of longitudinal data showed that C-reactive protein (P < 0.001), erythrocyte sedimentation rate (P < 0.005), Disease Activity Score in 28 joints (P < 0.001), mean blood pressure (P < 0.005) and augmentation index (P < 0.001) were significantly reduced after commencing anti-TNFα treatment. Increasing C-reactive protein was found to be associated with a reduction in SEVR (P = 0.02) and an increase in augmentation index (P = 0.001).

CONCLUSION

The present findings reveal that the SEVR is associated with markers of disease activity as well as highly prevalent classical CVD risk factors in RA, such as high blood pressure and diabetes. Further prospective studies are required to determine whether the SEVR predicts future cardiac events in RA.

Cardiac complications in patients with community-acquired pneumonia: incidence, timing, risk factors, and association with short-term mortality

BACKGROUND

Community-acquired pneumonia (CAP) affects >5 million adults each year in the United States. Although incident cardiac complications occur in patients with community-acquired pneumonia, their incidence, timing, risk factors, and associations with short-term mortality are not well understood.

METHODS AND RESULTS

A total of 1343 inpatients and 944 outpatients with community-acquired pneumonia were followed up prospectively for 30 days after presentation. Incident cardiac complications (new or worsening heart failure, new or worsening arrhythmias, or myocardial infarction) were diagnosed in 358 inpatients (26.7%) and 20 outpatients (2.1%). Although most events (89.1% in inpatients, 75% in outpatients) were diagnosed within the first week, more than half of them were recognized in the first 24 hours. Factors associated with their diagnosis included older age (odds ratio [OR]=1.03; 95% confidence interval [CI], 1.02-1.04), nursing home residence (OR, 1.8; 95% CI, 1.2-2.9), history of heart failure (OR, 4.3; 95% CI, 3.0-6.3), prior cardiac arrhythmias (OR, 1.8; 95% CI, 1.2-2.7), previously diagnosed coronary artery disease (OR, 1.5; 95% CI, 1.04-2.0), arterial hypertension (OR, 1.5; 95% CI, 1.1-2.1), respiratory rate ≥30 breaths per minute (OR, 1.6; 95% CI, 1.1-2.3), blood pH <7.35 (OR, 3.2; 95% CI, 1.8-5.7), blood urea nitrogen ≥30 mg/dL (OR, 1.5; 95% CI, 1.1-2.2), serum sodium <130 mmol/L (OR, 1.8; 95% CI, 1.02-3.1), hematocrit <30% (OR, 2.0; 95% CI, 1.3-3.2), pleural effusion on presenting chest x-ray (OR, 1.6; 95% CI, 1.1-2.4), and inpatient care (OR, 4.8; 95% CI, 2.8-8.3). Incident cardiac complications were associated with increased risk of death at 30 days after adjustment for baseline Pneumonia Severity Index score (OR, 1.6; 95% CI, 1.04-2.5).

CONCLUSIONS

Incident cardiac complications are common in patients with community-acquired pneumonia and are associated with increased short-term mortality. Older age, nursing home residence, preexisting cardiovascular disease, and pneumonia severity are associated with their occurrence. Further studies are required to test risk stratification and prevention and treatment strategies for cardiac complications in this population.

Altered coronary vascular control during cold stress in healthy older adults

Cardiovascular-related mortality increases in the cold winter months, particularly in older adults. Previously, we reported that determinants of myocardial O(2) demand, such as the rate-pressure product, increase more in older adults compared with young adults during cold stress. The aim of the present study was to determine if aging influences the coronary hemodynamic response to cold stress in humans. Transthoracic Doppler echocardiography was used to noninvasively measure peak coronary blood velocity in the left anterior descending artery before and during acute (20 min) whole body cold stress in 10 young adults (25 ± 1 yr) and 11 older healthy adults (65 ± 2 yr). Coronary vascular resistance (diastolic blood pressure/peak coronary blood velocity), coronary perfusion time fraction (coronary perfusion time/R-R interval), and left ventricular wall stress were calculated. We found that cooling (via a water-perfused suit) increased left ventricular wall stress, a primary determinant of myocardial O(2) consumption, in both young and older adults, although the magnitude of this increase was nearly twofold greater in older adults (change of 9.1 ± 3.5% vs. 17.6 ± 3.2%, P < 0.05, change from baseline in young and older adults and young vs. older adults). Despite the increased myocardial O(2) demand during cooling, coronary vasodilation (decreased coronary vascular resistance) occurred only in young adults (3.22 ± 0.23 to 2.85 ± 0.18 mmHg·cm(-1)·s(-1), P < 0.05) and not older adults (3.97 ± 0.24 to 3.79 ± 0.27 mmHg·cm(-1)·s(-1), P > 0.05). Consistent with a blunted coronary vascular response, absolute coronary perfusion time tended to decrease (P = 0.13) and coronary perfusion time fraction decreased (P < 0.05) during cooling in older adults but not young adults. Collectively, these data suggest that older adults demonstrate an altered coronary hemodynamic response to acute cold stress.

Cardiac complications in patients with community-acquired pneumonia: a systematic review and meta-analysis of observational studies

BACKGROUND

Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality. CAP can trigger acute cardiac events. We sought to determine the incidence of major cardiac complications in CAP patients to characterize the magnitude of this problem.

METHODS AND FINDINGS

Two investigators searched MEDLINE, Scopus, and EMBASE for observational studies of immunocompetent adults with clinical and radiological evidence of CAP that reported any of the following: overall cardiac complications, incident heart failure, acute coronary syndromes (ACS), or incident cardiac arrhythmias occurring within 30 days of CAP diagnosis. At a minimum, studies had to establish enrolment procedures and inclusion and exclusion criteria, enroll their patients sequentially, and report the incidence of cardiac complications as a function of their entire cohorts. Studies with focus on nosocomial or health care-associated pneumonia were not included. Review of 2,176 citations yielded 25 articles that met eligibility and minimum quality criteria. Seventeen articles (68%) reported cohorts of CAP inpatients. In this group, the pooled incidence rates for overall cardiac complications (six cohorts, 2,119 patients), incident heart failure (eight cohorts, 4,215 patients), acute coronary syndromes (six cohorts, 2,657 patients), and incident cardiac arrhythmias (six cohorts, 2,596 patients), were 17.7% (confidence interval [CI] 13.9-22.2), 14.1% (9.3-20.6), 5.3% (3.2-8.6), and 4.7% (2.4-8.9), respectively. One article reported cardiac complications in CAP outpatients, four in low-risk (not severely ill) inpatients, and three in high-risk inpatients. The incidences for all outcomes except overall cardiac complications were lower in the two former groups and higher in the latter. One additional study reported on CAP outpatients and low-risk inpatients without discriminating between these groups. Twelve studies (48%) asserted the evaluation of cardiac complications in their methods but only six (24%) provided a definition for them. Only three studies, all examining ACS, carried out risk factor analysis for these events. No study analyzed the association between cardiac complications and other medical complications or their impact on other CAP outcomes.

CONCLUSIONS

Major cardiac complications occur in a substantial proportion of patients with CAP. Physicians and patients need to appreciate the significance of this association for timely recognition and management of these events. Strategies aimed at preventing pneumonia (i.e., influenza and pneumococcal vaccination) in high-risk populations need to be optimized. Further research is needed to understand the mechanisms underlying this association, measure the impact of cardiac complications on other CAP outcomes, identify those patients with CAP at high risk of developing cardiac complications, and design strategies to prevent their occurrence in this population.

Influence of aortic pressure wave components determined noninvasively on myocardial oxygen demand in men and women

Myocardial oxygen consumption is increased by arterial stiffening. It is not known precisely how. This study aimed to evaluate the role of the incident and reflected pressure wave in raising myocardial oxygen demand. Central (aortic) pressure waveforms were generated from radial waveforms using a generalized transfer function in 1628 cardiology outpatients (1038 males and 590 females). Aortic waveforms were used to derive measures of incident and reflected waves, as well as to measure mean central systolic pressure (an indicator of systolic ventricular load), left ventricular ejection duration, and tension time index (a surrogate of myocardial oxygen demand) using validated techniques. Incident and reflected waves were measured using the conventional and an alternative method (aortic flow triangulation). Relationships were tested before and after correction for age, height, weight, heart rate, and mean arterial pressure using simple and multivariate linear regression models. Analyses were conducted separately by gender. In both genders (according to conventional or alternative methods of wave measurement), both the incident and reflected wave were strong predictors of tension time index (P<0.001). Both pressure waves raised the mean central systolic pressure (P<0.001). The reflected wave (P<0.001), unlike the incident wave (P>0.05), was also associated with a longer cardiac ejection duration. Tension time index (P<0.0001), mean central systolic pressure (P<0.001), and ejection duration (P<0.0001) were greater in women. Changes in arterial properties alter the nature of pressure wave propagation and predispose to cardiac ischemia (especially in women).