Novel Insights into the Pathobiology of Pulmonary Hypertension in Heart Failure with Preserved Ejection Fraction.

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common cause of pulmonary hypertension (PH) worldwide and is strongly associated with adverse clinical outcomes. The American Heart Association recently highlighted a call to action regarding the distinct lack of evidence-based treatments for PH due to poorly understood pathophysiology of PH attributable to HFpEF (PH-HFpEF). Prior studies have described cardio-physiological mechanisms to explain the development of isolated postcapillary PH (ipc-PH); however, the consequent increased pulmonary vascular (PV) resistance (PVR) may lead to the less understood and more fatal combined pre- and postcapillary PH (cpc-PH). Metabolic disease and inflammatory dysregulation have been suggested to predispose cpc-PH, yet the molecular mechanisms are unknown. Although PH-HFpEF has been studied to partly share vasoactive neurohormonal mediators with primary pulmonary arterial hypertension (PAH), clinical trials that have targeted these pathways have been unsuccessful. The increased mortality of PH-HFpEF patients necessitates further study into viable mechanistic targets involved in disease progression. We aim to summarize the current pathophysiological and clinical understanding of PH-HFpEF, highlight the role of known molecular mechanisms in the progression of PV disease, and introduce a novel concept that lipid metabolism may be attenuating and propagating PH-HFpEF.

The Efficacy of Cardiac Myosin Inhibitors Versus Placebo in Patients With Symptomatic Hypertrophic Cardiomyopathy: A Meta-Analysis and Systematic Review.

We aimed to assess the overall clinical impact of cardiac myosin inhibitors in hypertrophic cardiomyopathy (HCM). We performed a meta-analysis of published trials assessing the effect of cardiac myosin inhibitors (mavacamten and aficamten) on resting and Valsalva left ventricular outflow tract (LVOT) gradients and functional capacity in symptomatic HCM. The co-primary outcomes were mean percent change (mean difference [MD]) from baseline in LVOT gradient at rest and Valsalva LVOT gradient and the proportion of patients achieving New York Heart Association class improvement ≥1. The secondary outcomes included the mean percent change from baseline N-terminal pro-B-type natriuretic peptide, troponin I, and left ventricular ejection fraction (LVEF). A total of 4 studies (all randomized controlled trials, including 3 mavacamten-focused and 1 aficamten-focused trials) involving 463 patients were included in the meta-analysis. Compared with placebo, the cardiac myosin inhibitor group demonstrated statistically significant differences in the baseline percent change in mean LVOT gradient at rest (MD -62.48, confidence interval [CI] -65.44 to -59.51, p <0.00001) and Valsalva LVOT gradient (MD -54.21, CI -66.05 to -42.36, p <0.00001) and the proportion of patients achieving New York Heart Association class improvement ≥1 (odds ratio 3.43, CI 1.90 to 6.20, p <0.0001). Regarding the secondary outcomes, the intervention group demonstrated statistically significant reductions in mean percent change from baseline in N-terminal pro-B-type natriuretic peptide (MD -69.41, CI -87.06 to -51.75, p <0.00001), troponin I (MD, -44.19, CI -50.59 to -37.78, p <0.00001), and LVEF (MD -6.31, CI -10.35, -2.27, p = 0.002). In conclusion, cardiac myosin inhibitors may confer clinical and symptomatic benefits in symptomatic HCM at the possible expense of LVEF. Further trials with large sample sizes are needed to confirm our findings.

A profile on the CardioMEMS HF system in the management of patients with early stages of heart failure: an update.

INTRODUCTION: Over the past decade, there have been noteworthy advances in the evaluation and treatment of heart failure (HF). Despite an improved understanding of this chronic disease, HF is still one of the leading causes of morbidity and mortality in the United States and worldwide. Decompensation and rehospitalization of HF patients remain an integral problem in disease management, with significant economic implications. Remote monitoring systems have been developed to detect HF decompensation early and address it before hospitalization. The CardioMEMS HF system is a wireless pulmonary artery (PA) monitoring system that detects changes in PA pressure and transmits data to the healthcare provider. As changes in PA pressures occur early during HF decompensation, the CardioMEMS HF system allows providers to institute timely changes in HF medical therapies to alter the course of the decompensation. The use of the CardioMEMS HF system has been shown to reduce HF hospitalization and improve quality of life. AREAS COVERED: This review will focus on the available data supporting the expanded utilization of the CardioMEMS system in patients with HF. EXPERT OPINION: The CardioMEMS HF system is a relatively safe and cost-effective device that reduces the incidence of HF hospitalization and qualifies as intermediate-to-high value medical care.

Paraoxonases at the Heart of Neurological Disorders.

Paraoxonase enzymes serve as an important physiological redox system that participates in the protection against cellular injury caused by oxidative stress. The PON enzymes family consists of three members (PON-1, PON-2, and PON-3) that share a similar structure and location as a cluster on human chromosome 7. These enzymes exhibit anti-inflammatory and antioxidant properties with well-described roles in preventing cardiovascular disease. Perturbations in PON enzyme levels and their activity have also been linked with the development and progression of many neurological disorders and neurodegenerative diseases. The current review summarizes the available evidence on the role of PONs in these diseases and their ability to modify risk factors for neurological disorders. We present the current findings on the role of PONs in Alzheimer's disease, Parkinson's disease, and other neurodegenerative and neurological diseases.

The Behavioral and Social Dimension of the Public Health System of European Countries: Descriptive, Canonical, and Factor Analysis.

BACKGROUND: The state and prospects of the healthcare industry of a country are among its top priorities because the quality of life and health of its citizens are indicators of its success and competitiveness. The aim of this study is to conduct a theoretical analysis and qualitative and quantitative assessments of indicators by developing an integral indicator in the context of behavioral, social, demographic, and economic factors that characterize the level of healthcare system development in European countries using multivariate statistical modeling methods. METHODS: The study was implemented using Statistica 10 and Statistica Portable statistical packages. The statistical base of the study was formed using descriptive analysis; a group of 10 European countries was identified using a cluster analysis based on the application of an iterative divisive k-means method. The degree and significance of the interrelations between the components characterizing the studied groups of indicators were determined using canonical correlations by conducting a canonical analysis. Factor modeling is conducted by applying the analysis of the main components to determine the relevant indicators for assessing the level of healthcare system development to build integral indicators of the level of healthcare system development in European countries. RESULTS: The need to improve the level of healthcare system development in European countries was confirmed. Shortcomings and possible reserves for potential improvement of the healthcare system were identified. CONCLUSIONS: The results can help public authorities, officials and employees of the healthcare sector organize and conduct effective, timely, high-quality regulation and adjustment of the regulatory and legislative framework to improve healthcare system development.

Brain-type natriuretic peptide levels and invasive hemodynamic parameters in dialysis dependent patients.

BACKGROUND: Pulmonary hypertension (PH) is associated with increased mortality in patients with end-stage renal disease (ESRD). The prevalence of PH within ESRD as measured by right heart catheterization (RHC) is poorly described, and the correlation of BNP to pulmonary artery pressure (PAP) is unknown. METHODS: The renal transplant database at our center was used to identify adult ESRD patients from July 2013 to July 2015 who had a plasma BNP level measurement and invasive hemodynamic assessment by RHC within a 1-month period. Pulmonary hypertension was defined as a mean pulmonary artery pressure (PAP) ≥ 25 mmHg. Multivariate linear regression analysis was used to identify correlations between BNP and RHC parameters. To estimate the utility of BNP in the screening of PH, a receiver-operating characteristic (ROC) curve was generated. RESULTS: Eighty-eight patients were included in the study of which 43 had PH. Compared to patients without PH, BNP was significantly higher within the PH cohort (1619 ± 2602 pg/ml vs. 352 ± 491 pg/ml). A statistically significant association (r [86] = 0.60, p<0.001) between plasma BNP and mean PAP was identified. ROC curve indicated an acceptable predictive value of BNP in PH with a c-statistic of 0.800 (95% CI 0.708 - 0.892). CONCLUSIONS: In ESRD patients being considered for renal transplantation, PH is highly prevalent and BNP levels are elevated and significantly correlated with higher PAP. BNP may be a useful non-invasive marker of PH in these patients.

Internet Addiction, Symptoms of Anxiety, Depressive Symptoms, Stress Among Higher Education Students During the COVID-19 Pandemic.

Poor mental health is a growing concern among young people during the coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to assess the associations of Internet addiction with depressive symptoms, anxiety symptoms, and stress in higher education students during the COVID-19 pandemic, as well as to examine these mental health problems in the context of study-related characteristics. The research sample consisted of 3,099 participants from the Czech Republic (CZ: 1,422) and Slovak Republic (SK: 1,677). The Internet Addiction Test (IAT), the Generalized Anxiety Disorder (GAD-7) scale, the Patient Health Questionnaire for depressive symptoms (PHQ-9), and the Perceived Stress Scale (PSS) were used to measure mental health problems. The analyses also included demographic data (gender and age) and study-related characteristics (form of study, degree of study, field of study, distance between college and home, and housing during the semester). Based on the results of frequency and descriptive analyses, the prevalence of mental health problems was high. The most serious levels of Internet addiction (IAT cut-off point ≥ 50), to which attention should be paid, were found in 3.5% of Czech and 6.2% of Slovak students. Using the standard cut-off point of GAD-7 ≥ 10, 14.1% of Czech and 11.6% of Slovak students were identified with anxiety symptoms. Regarding the PHQ-9 with the cut-off point ≥ 10, 23.4% of Czech and 19.1% of Slovak students had depressive symptoms, which should be addressed. Using the PSS cut-off point ≥ 27, 12.9% of Czech students and 9.1% of Slovak students perceived high stress. The quantile regression analysis showed that Internet addiction was positively associated with anxiety symptoms, depressive symptoms, and stress in all of the analyzed cases (p-value < 0.001). In terms of study-related characteristics, the binomial logistic regression analysis revealed that risk factors for mental health problems in Czech and Slovak students were mainly full-time form of study and living away from home during the semester. Internet addiction, anxiety symptoms, depressive symptoms, and stress are issues that require increased attention, and professionals and policy-makers should implement interventions to effectively prevent and help students with psychological problems.

Understanding the relationships between health spending, treatable mortality and economic productivity in OECD countries.

Introduction: Population health is one of the highest priorities for countries, which can translate into increased economic prosperity. This encourages research on health in an economic context. Methods: The objective was to assess the relationships between health spending, treatable respiratory mortality, and gross domestic product (GDP) in countries of the Organization for Economic Co-operation and Development (OECD). The research was conducted with respect to health systems (tax-based, insurance-based) and gender differentiation of the productive population (aged 25-64 years). Descriptive analysis, regression analysis, and cluster analysis were used to achieve the main objective. The data covered the period from 1994 to 2016. Results: The results of the regression analysis revealed negative relationships between health spending and treatable respiratory mortality in countries with a tax-based health system for male and female working-age populations, as well as in countries with an insurance-based health system for male population. This means that higher health spending was associated with lower treatable respiratory mortality. Also, lower treatable mortality was associated with higher GDP, especially in the male productive population from countries with an insurance-based health system. In this study, countries with a tax-based health system were characterized by higher health spending, lower rates of treatable mortality from respiratory system diseases, and higher GDP compared to countries with an insurance-based health system. Males reported a higher mortality rate than females. Among the countries with a tax-based health system, the United Kingdom and Latvia showed less positive outcomes, while Italy and Iceland were the countries with the most positive outcomes. Among the countries with an insurance-based health system, Hungary and Slovakia reported poor outcomes, while France, Switzerland and Luxembourg were characterized by very positive outcomes. The United States showed a high mortality rate despite its high economic outcomes, i.e., health spending and GDP. Discussion: Health care financing in particular is one of the instruments of health policy. It seems that the leaders of countries should ensure a sufficient level of health financing, as higher health spending can contribute to lower mortality rates in a country. This may translate into higher productivity. Especially countries with underfunded health systems should increase their health spending.

Examining the Economic Perspective of Treatable Mortality: The Role of Health Care Financing and the Importance for Economic Prosperity.

Health is an essential element of economic life and is therefore considered a source of comparative economic development of countries. The aim of the study was to examine the associations between health care financing, specific treatable mortality of males and females of working age, and economic prosperity, taking into account to the classification of health systems applied in the countries of the Organization for Economic Co-operation and Development (OECD). An insurance-based health system and a tax-based health system were identified in these countries, and data were collected for the period 1994-2016. Descriptive analysis, panel regression analysis and cluster analysis were used to achieve the aim. The analytical process included economic indicators [health expenditure, gross domestic product (GDP)] and health indicators (treatable mortality from circulatory system diseases and endocrine, nutritional and metabolic diseases). The results revealed significant negative associations of health care financing with treatable mortality from circulatory system diseases and endocrine, nutritional, and metabolic diseases in both health systems and both gender categories. There were also negative associations between treatable mortality in both diagnosis groups and economic prosperity. These results have shown that health care financing is linked to economic prosperity also through health variability in the working age population. In terms of assessing economic and health outcomes, less positive and more positive countries were identified using cluster analysis. Countries such as Latvia with a tax-based health system and Hungary, Lithuania, Estonia with an insurance-based health system were characterized by great potential for improvements. Although reducing treatable mortality is a great motivation for public health leaders to increase health care financing, the importance for economic prosperity may be a more compelling argument. Effective interventions should be considered in the light of their regional, social and economic contexts.

Right Ventricular Dysfunction and Short-Term Outcomes Following Left-Sided Valvular Surgery: An Echocardiographic Study.

Background The prognostic value of echocardiographic evaluation of right ventricular (RV) function in patients undergoing left-sided valvular surgery has not been well described. The objective of this study is to determine the role of broad echocardiographic assessment of RV function in predicting short-term outcomes after valvular surgery. Methods and Results Preoperative echocardiographic data, perioperative adverse outcomes, and 30-day mortality were analyzed in patients who underwent left-sided valvular surgery from 2006 to 2014. Echocardiographic parameters used to evaluate RV function include RV fractional area change, tricuspid annular plane systolic excursion, systolic movement of the RV lateral wall using tissue Doppler imaging (S'), RV myocardial performance index, and RV dP/dt. Subjects with at least 3 abnormal parameters out of the 5 aforementioned indices were defined as having significant RV dysfunction. The study included 269 patients with valvular surgery (average age: 67±15, 60.6% male, 148 aortic, and 121 mitral). RV dysfunction was found in 53 (19.7%) patients; 30-day mortality occurred in 20 patients (7.5%). Compared with normal RV function, patients with RV dysfunction had higher 30-day mortality (22.6% versus 3.8%; P=0.01) and were at risk for developing multisystem failure/shock (13.2% versus 3.2%; P=0.01). Multivariate analyses showed that preexisting RV dysfunction was the strongest predictor of increased 30-day mortality (odds ratio: 3.5; 95% CI, 1.1-11.1; P<0.05). Conclusions Preoperative RV dysfunction identified by comprehensive echocardiographic assessment is a strong predictor of adverse outcomes following left-sided valvular surgery.

Changes in Alcohol Consumption and Determinants of Excessive Drinking During the COVID-19 Lockdown in the Slovak Republic.

As a result of the coronavirus disease 2019 (COVID-19) pandemic, countries have been forced to adopt strong restrictions, such as lockdown, which can lead to serious consequences for public health, including the problematic use of addictive substances. The aim of this cross-sectional study was to examine changes in alcohol consumption and to identify determinants against the background of excessive drinking during the COVID-19 lockdown in the Slovak Republic. The research included 445 respondents (33% males and 67% females), and the data collection through the questionnaire took place from April 29, 2020 to July 1, 2020. Measures such as drinking frequency, amount of alcohol and excessive drinking were used to examine alcohol consumption. Descriptive analysis and binary logistic regression were used to meet the main aim. The findings provide a closer look at the situation in the Slovak Republic and contribute to comprehensive international knowledge. The frequency of excessive drinking did not change in about half of respondents (53% of males and 69% of females). More respondents decreased their excessive drinking than increased, both among males (31 and 16%, respectively) and females (25 and 6%, respectively). Similar results were found for drinking frequency and amount of alcohol. Amongst Slovak respondents, an increase in excessive drinking was more common among males, younger people, smokers, and smokers who increased smoking during the lockdown. Especially in the case of vulnerable populations, public policies should consider a response to impending problems. The findings of this study encourage the implementation of effective and evidence-based prevention programs, which are more than necessary in the Slovak Republic.

Exploration of Influence of Socioeconomic Determinants on Mortality in the European Union.

Economic performance measured through the gross domestic product indicator and the poverty rate varies across the whole European Union, together with the considerable income inequalities in the long-term. Economic growth may not bring a reduction in the health inequalities in the individual countries themselves. In order to eliminate health inequalities, the different types of policies implemented in the health, social and economic systems need to be explored in more detail. Mortality is explored through an indicator of the standardised mortality rate for both sexes explained by the several socioeconomic determinants, among which variables such as the variations of the gross domestic product per capita, the healthcare expenditures, the unemployment rate, and the healthcare system financing. Almost in all the described cases, these dimensions have negative impact. All the influences are expressed in a relative way in order to be suitably interpretable. The analysis is not comprehensive; nevertheless, it contains 18 regression models to cover as many aspects as it is possible. The Discussion section offers an evaluation of the obtained results according to the outcome of the other studies.

Exploration of Disparities in Regions and Specialized Fields of Day Surgery System.

The main objective of this paper was to find similarities among eight Slovak regions from the viewpoint of five specialized day surgery fields and among specialized day surgery fields from the viewpoint of Slovak regions on the basis of day surgery operated and hospitalized patient counts. Day surgery data of paediatric patients and of adult patients from the National Health Information Centre during the years 2009-2017 were used. Correspondence analysis in two dimensions of the Slovak regions and of specialized day surgery fields was applied in order to achieve the paper's objective. The Kosice Region differs most from the overall national average in both groups of paediatric day surgery. This is caused by its largest proportions in the fields of Gynaecology (29.7%) and Urology (48.0%) (operated patients), and in the fields of Gynaecology (60.5%) and Surgery (21.6%) (hospitalized patients). The most different specialized day surgery fields from overall average are: Urology (operated paediatric patients), Gynaecology (hospitalized paediatric patients), Otorhinolaryngology (operated adult patients) and Ophthalmology (hospitalized adult patients). Urogenital system day surgery procedures (Gynaecology, Urology) are separated from other three fields (i.e., Surgery, Ophthalmology, Otorhinolaryngology) either in the first or in the second dimension of the singular value matrix decomposition.

Endothelin 1 Is Associated with Heart Failure Hospitalization and Long-Term Mortality in Patients with Heart Failure with Preserved Ejection Fraction and Pulmonary Hypertension.

BACKGROUND: The prevalence of pulmonary hypertension (PH) in heart failure with preserved ejection fraction (HFpEF) is increasing. We aim to study the role of big endothelin 1 (Big ET1), endothelin 1 (ET1), and neprilysin (NE) in HFpEF with PH. METHOD: This was a single center prospective cohort study including 90 HFpEF patients; 30 with no PH, 30 with postcapillary PH, and 30 with combined post- and precapillary PH. After enrollment, pulmonary venous and pulmonary arterial samples of Big ET1, ET1, and NE were collected during right heart catheterization. Subjects were then followed long term for adverse outcomes which included echocardiographic evidence of right ventricular dysfunction, heart failure hospitalization, and all-cause mortality. RESULTS: Patients with HFpEF-PH were found to have increased ET1 in pulmonary veins (endothelin from the wedge; ET1W) compared to controls (2.3 ± 1.4 and 1.6 ± 0.9 pg/mL, respectively). ET1W levels were associated with both PH (OR 2.7, 95% CI 1.5-4.7, p = 0.01) and pulmonary vascular resistance (OR 1.6, 95% CI 1.04-2.3, p = 0.03). No evidence of right ventricular dysfunction was observed after 1 year of follow-up. ET1W (OR 1.8, 95% CI 1.2-2.6, p = 0.01) and ET1 gradient (ET1G; OR 1.4, 95% CI 1.04-2, p = 0.03) were predictive of 1-year hospitalization. ET1G ≥0.2 pg/mL was associated with long-term mortality (log-rank 4.8, p = 0.03). CONCLUSION: In HFpEF patients, ET1W and ET1G are predictive of 1-year heart failure hospitalization, while elevated ET1G levels were found to be associated with long-term mortality in HFpEF. This study highlights the role of ET1 in developing PH in HFpEF patients and also explores the potential of ET1 as a prognostic biomarker.

Pre-operative right ventricular echocardiographic parameters associated with short-term outcomes and long-term mortality after CABG.

Background This analysis aims to assess the prognostic value of pre-operative right ventricular echocardiographic parameters in predicting short-term adverse outcomes and long-term mortality after coronary artery bypass graft (CABG). Methods Study design: Observational retrospective cohort. Pre-operative echocardiographic data, perioperative adverse outcomes (POAO) and long-term mortality were retrospectively analyzed in 491 patients who underwent isolated CABG at a single academic center between 2006 and 2014. Results Average age of enrolled subjects was 66 ± 11.5 years with majority being male (69%). 227/491 patients had 30 days POAO (46%); most common being post-operative atrial fibrillation (27.3%) followed by prolonged ventilation duration (12.7%). On multivariate analysis, left atrial volume index ≥42 mL/m2 (LAVI) (OR (95% CI): 1.98 (1.03-3.82), P = 0.04), mitral E/A >2 (1.97 (1.02-3.78), P = 0.04), right atrial size >18 cm2 (1.86 (1.14-3.05), P = 0.01), tricuspid annular plane systolic excursion (TAPSE) <16 mm (1.8 (1.03-3.17), P = 0.04), right ventricular systolic pressure (RVSP) ≥36 mmHg (pulmonary hypertension) (1.6 (1.03-2.38), P = 0.04) and right ventricle myocardial performance index (RVMPI) >0.55 (1.58 (1.01-2.46), P = 0.04) were found to be associated with increased 30-day POAO. On 3.5-year follow-up, cumulative survival was decreased in patients with myocardial performance index (MPI) ≥0.55 (log rank: 4.5, P = 0.034) and in patients with mitral valve E/e' ≥14 (log rank: 4.9, P = 0.026). Conclusion Pre-operative right ventricle dysfunction (RVD) is associated with increased perioperative complications. Furthermore, pre-operative RVD and increased left atrial pressures are associated with long-term mortality post CABG.

Patient Factors But Not the Use of Novel Anticoagulants or Warfarin Are Associated With Internal Jugular Vein Access-Site Hematoma After Right Heart Catheterization.

INTRODUCTION: Right heart catheterization (RHC) is routinely performed to assess hemodynamics. Generally, anticoagulants are held prior to the procedure. At our center, anticoagulants are continued and ultrasound guidance is always used for internal jugular vein access. A micropuncture access kit is used to place a 5 or 6 Fr sheath using the modified Seldinger technique. Manual compression is applied for 10-15 min and the patient is observed for at least 2 hours after the procedure. In a retrospective analysis, we investigated the risk of bleeding complications associated with RHC via the internal jugular vein in patients with and without full anticoagulation. METHODS AND RESULTS: Our catheterization laboratory database was searched for adult patients who underwent RHC by a single operator between January 2012 and December 2015. A total of 571 patients were included in the analysis. Baseline characteristics, labs, relevant invasive hemodynamics, co-morbid conditions, and incidence of access-site hematoma are presented. Multivariable binary logistic regression was performed using IBM SPSS v. 23.0 software. Statistically significant associations with access-site hematoma were observed with body mass index (P=.02; 95% confidence interval [CI], 1.0-1.1), right atrial pressure (P=.03; 95% CI, 0.7-0.9), and dialysis dependence (P<.01; 95% CI, 0.1-0.6). There was no association of access-site hematoma with the use of anticoagulants (P>.99). CONCLUSION: The incidence of internal jugular vein access-site hematoma is small when using careful access techniques for RHC even with the continued use of novel oral anticoagulants and warfarin. Patient characteristics and co-morbid conditions are related to bleeding complications.

Practical echocardiographic approach for risk stratification of patients with acute pulmonary embolism.

Acute pulmonary embolism remains a common cause of mortality. Early diagnosis and appropriate risk stratification is necessary to individualize treatment strategy. Computed tomography scan of the pulmonary arteries is routinely used to diagnose acute pulmonary embolism and in some cases is useful to assess right ventricular dilation. In patients with acute pulmonary embolism, right ventricular dilation and dysfunction indicates a high-risk situation where immediate administration of thrombolytic agent, catheter-directed thrombolysis, or surgical embolectomy could be considered. A bedside 2D echocardiogram at the time of presentation could provide additional morphological, functional, and hemodynamic parameters including right ventricular dilation, McConnell's sign, reduced tricuspid annular plane systolic excursion (TAPSE), interventricular septal flattening, abnormal right ventricular hemodynamics and in rare cases thrombi in the inferior vena cava, right atrium or ventricle en route to pulmonary arteries may also be visualized. This additional information is useful for selection of appropriate treatment modality. Thus, our objective is to provide a practical echocardiographic approach for risk stratification of patients with acute pulmonary embolism.

In vivo assessment of arterial stiffness in the isoflurane anesthetized spontaneously hypertensive rat.

BACKGROUND: Rodent models are increasingly used to study the development and progression of arterial stiffness. Both the non-invasive Doppler derived Pulse Wave Velocity (PWV) and the invasively determined arterial elastance index (EaI) have been used to assess arterial stiffness in rats and mice, but the need for anesthetic agents to make these in vivo estimates may limit their utility. Thus, we sought to determine: 1) if known differences in arterial stiffness in spontaneously hypertensive rats (SHR) are detectable by PWV and EaI measurements when made under isoflurane anesthesia, and 2) if these two uniquely acquired assessments of arterial elasticity correlate. METHODS: We obtained PWV and EaI measurements in isoflurane anesthetized young and old SHRs, which are known to have significant differences in arterial stiffness. Doppler pulse waves were recorded from carotid and iliac arteries and the distance (D) between probe applantation sites was recorded. Simultaneously, an EKG was obtained, and the time intervals between the R-wave of the EKG to the foot of the Doppler waveforms were measured and averaged over three cardiac cycles. Pulse-transit time (T) of the carotid to iliac artery was determined, and PWV was calculated as Distance (D)/Time (T), where D = the distance from the carotid to the iliac notch and T = (R to iliac foot) - (R to carotid foot). EaI was subsequently determined from pressure volumes loops obtained via left ventricle catheterization. RESULTS: PWV and EaI were found to be significantly faster in the older rats (13.2 ± 2.0 vs. 8.0 ± 0.8 m/sec, p < 0.001; 120 ± 20 vs. 97 ± 16 mmHg/µl/g, p <0.05). Bland-Altman analyses of intra- and inter-observer measures demonstrate a statistically significant relationship between readings (p < 0.0001). PWV and EaI measurements were found to be significantly and positively correlated with a correlation coefficient of 0.53 (p < 0.05). CONCLUSION: Our study suggests that isoflurane administration does not limit Doppler PWV or EaI measures in their ability to provide accurate, in vivo assessments of relative arterial stiffness in isoflurane anesthetised SHR rats. Furthermore, PWV data obtained in these rats correlate well with invasively determined EaI.