Blood Pressure Gradient Research Articles

Hybrid repair of a giant left subclavian artery aneurysm and arch coarctation in a patient with Larsen syndrome.

A 34-year-old male was admitted to our emergency department with progressively aggravated hoarseness and sudden onset of chest and neck pain. General examination was remarkable for severe scoliosis (Panel A) and a blood pressure gradient of >20 mmHg between upper and lower extremities. Computed tomography angiography (CTA) revealed a giant left subclavian artery (LSA) aneurysm (55 × 47 mm, asterisk), aortic arch coarctation, and severely tortuous descending aorta. In addition, an isolated left vertebral artery (ILVA) arose from the arch (Panel B-C). Whole-exome sequencing analysis identified p.Gly488Ser mutation in FLNB, indicating a diagnosis of Larsen syndrome. Considering the patient’s refusal of open surgery and the acutely worsening symptoms due to the pending rupture of the LSA aneurysm, a less-invasive hybrid approach was accepted as reasonable by interdisciplinary consensus. First, through the right femoral artery, a 20 F sheath (W.L. Gore and Associates, Newark, Del) was advanced across the arch coarctation, facilitating the delivery of the aortic stent. Then, a Gore cTAG stent was implanted at the arch distal to the innominate artery orifice, followed by a balloon-expandable Cheatham-Platinum stent (NuMED, Hopkinton, USA) deploying at the coarctation segment. Second, the membrane of the cTAG stent was penetrated with an aspiration biopsy needle through the left common carotid artery (LCCA). The fenestration was then expanded by balloons and LCCA was stented with a 120 × 40 mm covered endograft (Panel D–F; Supplementary material online, Video S1). After the endovascular procedures, the ILVA was anastomosed end-to-side to LCCA. Finally, the distal outlet of LSA aneurysm was ligated, and a bypass from LCCA to distal LSA was performed with a 6 mm Gore-Tex prosthetic graft (Panel G). Completion angiography (Panel H; Supplementary material online, Video S2) and postoperative CTA (Panel I) confirmed exclusion of the aneurysm and patency of all the supra-arch vessels. The postoperative course was uneventful and the patient was discharged on the 4th day after surgery.

Climate Factors May Influence Glomerular Filtration Rate in Nephrology Patients

INTRODUCTIONApproximately 37 million U.S. adults have chronic kidney disease (CKD), characterized by reduced glomerular filtration rate (GFR). Previous work has shown GFR to be sensitive to certain environmental features, such as heightened temperature and pollution. Other components of climate merit investigation.PURPOSETo examine the effects of temperature, air pressure, and humidity on GFR.METHODSWe evaluated 322 nephrology patients who were consecutively admitted to a single hospital between January 2017 and July 2018. At intake, patients were assessed for demographic, anthropometric, and cardiometabolic parameters, and a detailed medical history was collected. The exact ambient temperature, air pressure, and humidity was documented for each patient corresponding to their time of admission. We characterized the study sample with basic descriptive statistics. Linear regression tested the effect of climate variables on GFR holding all significant confounders constant.RESULTSPatients were 65.8 ± 17.0 years old, 50.9% were male, 42.3% were obese, 12.3% reported smoking, 21.9% reported drinking, 16.8% had a diagnosis of cancer, 48.1% had diabetes, 26.1% had coronary artery disease, 1.9% had hepatitis, 6.5% had end‐stage renal disease, 3.4% had a kidney transplant, and 8.4% had used dialysis (either currently or in the past). Systolic blood pressure was 134.5 ± 37.2 mmHg, diastolic pressure was 72.8 ± 18.4 mmHg, hemoglobin was 11.6 ± 2.6 g/dL, creatinine was 2.8 ± 1.5 mg/L, and GFR was 26.5 ± 12.3 mL/min. GFR was correlated with humidity (p=0.029) but not temperature (p=0.170) or air pressure (p=0.404). Linear regression found each additional percentage point of humidity at the time of intake to correspond to a reduction in GFR of 7.6 mL/min (p=0.018; 95% CI: ‐1.314 to ‐13.899) holding all significant confounders constant: sex (p=0.027), diastolic blood pressure (p=0.033), hemoglobin (p<0.001), diagnosis of cancer (p=0.001), diagnosis of coronary artery disease (p=0.028), diagnosis of peripheral vascular disease (p=0.041), diagnosis of hepatitis (p=0.020), hyperglycemia (p=0.001), current alcohol intoxication (p=0.023), and use of dialysis (p<0.001). The overall model was significant (p<0.001; r2=0.317). Using all of the same predictors, but holding constant CKD stage (p<0.001), humidity remained significant (β = ‐6.837; p=0.029; 95% CI: ‐0.703 to ‐12.970). Temperature and air pressure were insignificant in both models (p>0.500); humidity remained significant (p<0.025) when controlling for them. All other potential confounders were tested; none were significant (p>0.100) and all combinations of inclusion in the model preserved the significance (p<0.025) and magnitude (β < ‐7.000) of humidity.CONCLUSIONSAmbient humidity demonstrated a robust and resilient effect on kidney function. Higher humidity corresponded to a reduction in estimated GFR across all stages of CKD and within stages. Other climate factors exhibited no effect. A possible mechanism is the decrease in evaporative cooling leading to additional sweat loss, reduced plasma volume, and a lower blood pressure gradient in the glomerulus.

Intermediate and Long Term Follow Up of Balloon Angioplasty for Native Coarctation of the Aorta in Neonates and Infants

Background: Balloon angioplasty (BA) became an alternative procedure for the management of CoA, which initially performed at 1983 (5). The effectiveness of BA for the management of native CoA remains controversial in neonates (less than one month) and infants under the first year of life, in spite of its acceptable morbidity and the reduced complication rates. This controversy was due to higher re-stenosis rate and the increased risk of aneurysm formation present with CHF, which might also increase the surgical risk. Objective: To study the intermediate and the long-standing effects of BA for native CoA in neonates and infants and to determine any predictive factors for the outcome. Patients and Method: Included in the study were all patient 12 days to 11 months referred for possible balloon dilation to our Ibn-Albaitar teaching hospital department of congenital cardiac intervention with evidence of discrete coarctation of aorta. The hemodynamic data, angiogram and clinical records of 63 patients were examined with follow up data from 2 to 138 months (median 72 months). Results: Immediate success with balloon angioplasty was achieved in 35 Patients of 63 patients. 33 patients (52 %) with intermediate follow up data ( rang 12 to 138 months ) available are asymptomatic and normotensive with insignificant arm to leg blood pressure gradient (is lellss than 20 mmHg). 28 patients (44.4%) with primary successful result showed increase in gradient at 2 to 86 months after angioplasty requiring re-intervention in 28 Patients. Follow up after 84 months was available in 55 patients, 92% of whom are normotensive and have not required additional intervention. No additional intervention was needed in our patients > 7 years old. 17 of 29 surviving neonates who initially had a successful dilatation required re-angioplasty or operation after angioplasty. Transverse arch hypoplasia showed negligible effect on blood pressure gradient; whereas isthmus hypoplasia is linked with re-intervention in 14 % of patients. A small aneurysm was noted in 1 (1.5%) patients of 63 Patients. Conclusion: BA of native CoA is effective in neonates, infants under the first year of life, and also in the older children, the aneurysm formation is rare, and however life time follow up is reasonable.

Dyspnea Declare Yourself! Decoding Doppler

AN APPRECIATION of the utility of echocardiographic Doppler spectral profile analysis in diagnosing cardiac pathology and guiding surgical intervention more than justifies an investment in obtaining proficiency in these skills. Given the relatively low incidence of significant complications associated with transesophageal echocardiographic examination, the facile use of both spectral and color Doppler principles to diagnose unusual pathology is essential. Doppler modalities are used to characterize blood flow, pressure gradients, chamber dimensions, and other anatomic and physiological parameters. The authors present a case in which several Doppler principles were used to evaluate and diagnose the etiology of dyspnea and a high aortic valve gradient.

Diagnosis of Coarctation of the Aorta From Infancy to Adulthood

Diagnosis of Coarctation of the Aorta From Infancy to Adulthood

Color-coded summation images for the evaluation of blood flow in endovascular aortic dissection fenestration

BackgroundTo analyze the benefit of color-coded summation images in the assessment of target lumen perfusion in patients with aortic dissection and malperfusion syndrome before and after fluoroscopy-guided aortic fenestration.MethodsBetween December 2011 and April 2020 25 patients with Stanford type A (n = 13) or type B dissection (n = 12) and malperfusion syndromes were treated with fluoroscopy-guided fenestration of the dissection flap using a re-entry catheter. The procedure was technically successful in 100% of the cases and included additional iliofemoral stent implantation in four patients. Intraprocedural systolic blood pressure measurements for gradient evaluation were performed in 19 cases. Post-processed color-coded DSA images were obtained from all DSA series before and following fenestration. Differences in time to peak (dTTP) values in the compromised aortic lumen and transluminal systolic blood pressure gradients were analyzed retrospectively. Correlation analysis between dTTP and changes in blood pressure gradients was performed.ResultsMean TTP prior to dissection flap fenestration was 6.85 ± 1.35 s. After fenestration, mean TTP decreased significantly to 4.96 ± 0.94 s (p < 0.001). Available systolic blood pressure gradients between the true and the false lumen were reduced by a median of 4.0 mmHg following fenestration (p = 0.031), with significant reductions in Stanford type B dissections (p = 0.013) and minor reductions in type A dissections (p = 0.530). A moderate correlation with no statistical significance was found between dTTP and the difference in systolic blood pressure (r = 0.226; p = 0.351).ConclusionsHemodynamic parameters obtained from color-coded DSA confirmed a significant reduction of TTP values in the aortic target lumen in terms of an improved perfusion in the compromised aortic region. Color-coded DSA might thus be a suitable complementary tool in the assessment of complex vascular patterns prevailing in aortic dissections, especially when blood pressure measurements are not conclusive or feasible.

How myocardial work could be relevant in patients with an aortic valve stenosis?

Abstract Funding Acknowledgements Type of funding sources: None. Background Speckle tracking based myocardial work calculation is an attractive method to assess left ventricular (LV) myocardial function. In case of aortic stenosis (AS), assessment of work indices is challenging because it requires an accurate evaluation of LV-pressure curves. Therefore, we sought to evaluate the performances of two distinct methods for the estimation of myocardial work indices and to provide a quantitative comparison with invasively measured data. Methods Model-based and template-based methods were defined and applied for the evaluation of LV pressures on 67 AS patients. Global Constructive (GCW), Wasted (GWW), Positive (GPW), Negative (GNW) myocardial work and Global Work Efficiency (GWE) and Index (GWI) parameters were calculated using the available software computing the indices using brachial blood pressure and trans-aortic mean pressure gradient for estimating the LV pressures versus using a model-based and homemade software. A complete comparison was performed with invasive measurements. Results Patients were characterized by mean pressure gradient of 49.8 ± 14.8 mmHg, LV ejection fraction of 59 ± 8%, the global longitudinal strain was -15.0 ± 4.04%, GCW was 2107 ± 800mmHg.% (model-based method) and 2483 ± 1068mmHg.% (template-based method). The root mean square error (RMSE) and correlation were calculated for each patient and for each pressure estimation methods. The mean RMSE are 33.9mmHg and 40.4mmHg and the mean correlation coefficients are 0.81 and 0.72 for the model-based and template-based methods respectively. Correlation coefficient and Bland-Altman analysis were performed for the six work indices. The two methods present correlation coefficient r2 &amp;gt; 0.75 for almost all the indices. Conclusion The two non-invasive methods of LV pressure estimation and the work indices computation correlate with invasive measurements and computations for AS patients. Although the model-based approach requires less information and is associated with slightly better performances, the implementation of template-based method is easier and seems more appropriate in a clinical practice. Abstract Figure. SUMMARY

Image-Based Computational Hemodynamics Analysis of Systolic Obstruction in Hypertrophic Cardiomyopathy.

Hypertrophic Cardiomyopathy (HCM) is a pathological condition characterized by an abnormal thickening of the myocardium. When affecting the medio-basal portion of the septum, it is named Hypertrophic Obstructive Cardiomyopathy (HOCM) because it induces a flow obstruction in the left ventricular outflow tract. In any type of HCM, the myocardial function can become compromised, possibly resulting in cardiac death. In this study, we investigated with computational analysis the hemodynamics of patients with different types of HCM. The aim was quantifying the effects of this pathology on the intraventricular blood flow and pressure gradients, and providing information potentially useful to guide the indication and the modality of the surgical treatment (septal myectomy). We employed an image-based computational approach, integrating fluid dynamics simulations with geometric and functional data, reconstructed from standard cardiac cine-MRI acquisitions. We showed that with our approach we can better understand the patho-physiological behavior of intraventricular blood flow dynamics due to the abnormal morphological and functional aspect of the left ventricle. The main results of our investigation are: (a) a detailed patient-specific analysis of the blood velocity, pressure and stress distribution associated to HCM; (b) a computation-based classification of patients affected by HCM that can complement the current clinical guidelines for the diagnosis and treatment of HOCM.

Factors Associated With an Abnormal Blood Pressure Response During Exercise After Coarctation Repair.

Although resting blood pressures following aortic arch repair or the extended end-to-end anastomosis (EEA) repair for coarctation can be physiologic, factors associated with an abnormal blood pressure response after exercise are unknown. We measured blood pressure gradients following exercise in children who had undergone previous repair in accordance with a surgical selection algorithm and sought to identify factors associated with an abnormal blood pressure response. In accordance with our practice's surgical algorithm for repair of coarctation, infants were stratified to aortic arch repair when the distal transverse arch-to-left carotid artery ratio (DTA:LCA) ≤ 1.0, or when a brachiocephalic trunk or intra-cardiac lesion requiring repair was present. A thoracotomy and EEA were otherwise used. A follow-up exercise stress test (EST) measured the arm:leg blood pressure gradient after exercise, and a gradient ≥ 20 mm Hg was defined as an abnormal blood pressure response. Thirty-seven infants who had previously undergone coarctation repair (aortic arch repair-19, EEA-18) completed an EST at 12.3 ± 2.2 years of age. Thirteen (35%) children (aortic arch repair-5, EEA-8; p = .3) exhibited an abnormal blood pressure response. Factors associated with an abnormal blood pressure response included: smaller DTA:LCA ratios prior to repair (1.0 ± .2 vs. 1.2 ± .3; p = .04) and greater body weight at the time of EST (57.5 ± 19.1 vs. 40.9 ± 15.6 kg; p = .03). An abnormal blood pressure response following exercise is associated with smaller DTA:LCA ratios at the time of repair and increased weight during follow-up suggesting that patients with these factors warrant close observation.

652 Myocardial work in patients undergoing transcatheter aortic valve implantation: clinical value and implications for outcome

Abstract Aims Non-invasive myocardial work (MW) quantification has emerged in the last years as an alternative echocardiographic tool for myocardial function assessment. This new parameter provides a less loading-dependent evaluation of myocardial performance through the combined assessment of global longitudinal strain (GLS) and non-invasive left ventricle (LV) pressures. The role of MW as a marker of cardiac dysfunction and reverse remodelling in patients with severe aortic stenosis (AS) after aortic valve implantation (TAVI) has not been adequately investigated. This study aims to evaluate MW indices as early echocardiographic markers of LV reverse remodelling within a month after TAVI and their prognostic value. Methods and results We conducted a single-centre prospective study, enrolling 70 consecutive patients (mean age 80.1 ± 5.5 years) with severe AS undergoing TAVI between 2018 and 2020, selected from the EffecTAVI registry. Exclusion criteria were prior valve surgery, severe mitral stenosis, permanent atrial fibrillation, left bundle branch block (LBBB) at baseline, and suboptimal quality of speckle-tracking image analysis. Echocardiographic assessment was performed before TAVI and at 30-day follow-up. Clinical, demographic, and resting echocardiographic data were recorded, including quantification of 2D global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). LV peak systolic pressure was estimated non-invasively from the sum of systolic blood pressure and trans-aortic mean gradient. One month after the procedure, there was a significant improvement of LV GLS (−17.94 ± 4.24% vs. −19.35 ± 4.31%, before and after TAVI respectively, P = 0.002), as well as a significant reduction of GWI (2430 ± 586 mmHg% vs. 1908 ± 472 mmHg%, P &amp;lt; 0.001), GCW (2828 ± 626 mmHg% vs. 2206 ± 482 mmHg%, P &amp;lt; 0.001), and GWW (238 ± 207 mmHg% vs. 171 ± 118 mmHg%, P = 0.006). Conversely, MWE did not significantly change early after intervention (90.53 ± 6.05% vs. 91.45 ± 5.05%, P = 0.204). After TAVI, 30 patients (42.8%) developed LV dyssynchrony due to LBBB or pacemaker implantation. When the population was divided according to the presence or absence of LV dyssynchrony at 30-day follow-up, a significant reduction in GWW was found only in those without dyssynchrony (244 ± 241 vs. 141 ± 110 mmHg% with and without dyssynchrony respectively, P = 0.002). Consistently, in this subgroup, MWE significantly improved post-TAVI (90 ± 7 vs. 93 ± 5%, P = 0.002), while a trend of MWE reduction was observed in patients who developed dyssynchrony post-TAVI (91 ± 4 vs. 89 ± 5%, P = 0.164). In the overall population, a baseline value of MWE&amp;lt; 92% was associated with an increased rate of cardiovascular events (composite of all-cause death and rehospitalization for heart failure) at 1-year follow-up (22.2 vs. 3.1%, long rank, P = 0.016). Conclusions In patients with severe AS undergoing TAVI a significant reduction of GWW and improvement of MWE can be detected only in those who did not develop LV dyssynchrony. In this setting, MWE lower than 92% at baseline is associated with poor outcome. Thus, MWE could represent an alternative tool for myocardial function assessment in patients receiving TAVI.

Real-time CMR guidance for intracardiac and great vessel pressure mapping in patients with congenital heart disease using an MR conditional guidewire-results of 25 patients.

The aim of this study was to test a CE-certified MR-conditional guidewire to facilitate blood pressure measurement in cardiovascular magnetic resonance (CMR) using fluid-filled catheters in patients with congenital heart disease (CHD). The main purpose was to determine procedural success in a post market clinical follow-up (PMCF) for routine procedure in a diagnostic and interventional workflow. Real-time CMR provides high quality imaging without the risk of exposing the patient to X-rays, especially for patients with irregular heart anatomy and patients who are susceptible to radiation and iodinated contrast media. To date, the assessment of blood pressure gradients is not a common feature of CMR, as these gradients cannot be accurately evaluated in routine CMR. Twenty-five CHD patients who were planned for combined clinical CMR and diagnostic and/or interventional catheterization were enrolled in the trial. Prior to inclusion, a specific procedure for catheterization in CMR was defined, encompassing the assessment of pressure and pressure gradients in the heart and great vessels. By the use of an MR-conditional guidewire we successfully measured specific pressure and pressure gradients in up to 92% of cases with liquid-filled catheters which were guided exclusively under CMR guidance. There were no guidewire-related adverse events, and guidewire guidance and manipulation of catheters were successful. Using a MR-conditional guidewire assists in easily reaching targets in the heart and great vessels and makes the catheter itself visible, so that invasive blood pressure assessment by CMR guidance with liquid-filled catheters can be improved. Cardiovascular magnetic resonance (CMR); congenital heart disease (CHD); cardiac catheterization; magnetic resonance; pressure; guidewire.

Abstract 10882: Validation of a Continuous Flow Pressure Gradient for Coarctation Severity Assessment

Introduction: Coarctation of the aorta (CoA) severity is assessed via trans-CoA blood pressure gradient (BPG) estimated using simplified Bernoulli equation (SBE) with indices from noninvasive Doppler echocardiography (echo). However, simplifications of the SBE and inconsistent readings through a suboptimal insonation window limit diagnostic accuracy (DA). In a rabbit model mimicking human CoA (Fig. 1A), catheter vs. Doppler comparison of BPG revealed diastolic continuous-flow pressure gradient (CFPG) was independently associated with severity. We therefore hypothesized the unique properties of CFPG would improve DA in humans. Methods: SBE and CFPG were quantified using color flow Doppler in humans and rabbits with discrete non-recurrent CoA before repair (Fig. 1B). Quantifications used peak velocity proximal to (V p ) and at the CoA (V pk ), early diastolic velocity (V d ), doppler velocity index (DVI), and normalized diastolic pressure half-time (dPHT; see Fig. 1B and C for definitions). Results were compared with measured BPG in rabbits (peak-to-peak catheter BPG) and humans (upper-lower extremity BPG). There was a total of 18 human and 26 rabbit cases; significance was defined a priori as a BPG of ≥20 mmHg. A CFPG ≥4 mmHg threshold was identified by maximizing sensitivity plus specificity in receiver operative curves (ROC). Results: Accuracy measures (Fig. 1D) revealed the superior performance of CFPG vs. SBE. Although reports suggest &lt;60% of measured BPG can be explained with SBE, CFPG yielded a specificity of 78% in humans. Similar improvements were observed in rabbits. Results confirm the potential DA of CFPG in echo-based CoA assessment. Fig. 1- (A) MRI confirming morphological similarities between rabbit and human CoA, (B) Spectral Doppler images show diastolic continuous flow, (C) indices derived from the generalized Bernoulli equation assuming exponential diastolic pressure loss, (D) diagnostic performance for CFPG vs. conventional SBE.

Abstract 9310: Aortic Arch Shape After Coarctation Repair Predicts Exercise Capacity: A Multicenter Analysis

Introduction: Patients with coarctation of the aorta (CoA) have decreased exercise capacity despite successful repair with no anatomic obstruction. Altered aortic arch shape after surgical repair may increase resistance to flow and affect flow distribution. This study correlates parameters of aorta size and flow with exercise capacity after successful CoA repair. Methods: We retrospectively reviewed patients with repaired CoA at 4 centers who had cardiac magnetic resonance imaging (CMR) and an exercise stress test with respiratory exchange ratio ≥ 1.09 within 1 year. Patients with significant valve disease, outflow tract obstruction, or need for cardiac bypass outside of their arch repair were excluded. Aorta size mismatch (D AAo /D DAo ), defined by the ratio of ascending (AAo) to proximal descending aorta (DAo) diameter, and DAo flow as a percentage of AAo flow, were measured from CMR. Each parameter was correlated with percent predicted peak oxygen consumption (VO2 max). Results: Forty-six patients (age 26 ± 8.4 years) with left ventricular ejection fraction (LVEF) &gt; 52%, met inclusion criteria. Larger D AAo /D DAo and lower %DAo flow correlated significantly with lower VO2 max (Fig). Compared to those with normal VO2 max (n=25), patients with VO2 max &lt;90% predicted (n=21) had a primary repair at an older age (p=0.03) and smaller DAo diameter/m 2 (p=0.04). There were no significant differences in prevalence of arch obstruction by echocardiogram, LVEF, hypertension, blood pressure gradient at rest or exercise, or AAo diameter/m 2 between groups. Conclusions: Aorta size mismatch, due to AAo dilation or small DAo, and associated decreased %DAo flow, correlate significantly with decreased exercise capacity after CoA repair in patients with normal left ventricular systolic function. CMR measurements of aorta geometry and flow can inform the definition of a successful repair and suggest that indications for re-intervention may not be limited to discrete re-coarctation.

Multi-centre cross-sectional study on vascular remodelling in children following successful coarctation correction.

Coarctation of the aorta is an arteriopathy with life-long sequelae, with remarkably increased cardiovascular events in young adults even after successful repair and despite blood pressure status. There are data on arterial remodelling in adults after coarctation correction, however, these data are scarce in childhood. Thus, the aim of this cross-sectional study was to evaluate changes in arterial wall function and morphology in children following successful coarctation repair and to compare these changes among patients with different blood pressure status and coarctation correction modes. Blood pressure status, echocardiographic parameters, arterial wall structure and stiffness, endothelial function and central blood pressure measurements were evaluated in 110 children aged 6-18 years following successful coarctation repair with right arm blood pressure not exceeding leg blood pressure by ≥20 mmHg. The prevalence of arterial hypertension was 50%. The mean carotid intima-media thickness SDS was 3.1 ± 1.5 and above 1.65 SDS in 91 of 110 patients. Increased right carotid intima-media thickness was associated with left ventricular hypertrophy, office blood pressure difference between leg and right arm, recoarctation in the past and interventional coarctation correction. Increased local common carotid artery stiffness was associated with increased pulse pressure and central systolic blood pressure. Potentially decreased endothelial function was related to a slight increase of peak and mean systolic gradient in the descending aorta. After successful coarctation repair and with a low blood pressure gradient, children still have a high prevalence of arterial hypertension and significant arterial remodelling, indicating accelerated biological age and advanced arteriosclerosis.

Long-Term Outcomes of the Coarctation of the Aorta Stent Trials.

Long-term outcome data of stent-implantation for coarctation of the aorta are limited. We report up to 5 years of postimplant follow-up in patients enrolled into the COAST (Coarctation of the Aorta Stent Trial) and the COAST II trial (Covered Cheatham-Platinum Stents for Prevention or Treatment of Aortic Wall Injury Associated With Coarctation of the Aorta), evaluating the bare and Covered Cheatham-Platinum Stents for the treatment of coarctation of the aorta and associated aortic wall injury. Data was prospectively collected during the 2 multi-center studies, enrolling 248 patients (COAST: n=121, COAST II: n=127). Late follow-up data (48–60 month) was compared with immediate (1 month) and early (12 months) follow-up. There was a notable decrease in the use of antihypertensive medication, from 53% at immediate, to 42% at early, and 29% at late follow-up. The cumulative incidence of stent fractures was 0% immediately, 2.9% at early, and 24.4% at late follow-up. Independent predictors for stent fractures at late follow-up were age <18 years, male sex, minimum stent diameter ≥12 mm, and use of bare metal stent. The cumulative incidence of reintervention was 1.6% at immediate, 5.1% at early, and 21.3% at late follow-up. Independent predictors for reinterventions at late follow-up were age <18 years, post implantation systolic arm-leg blood pressure gradient ≥10 mm Hg, minimum stent diameter at implantation <12 mm, and initial coarctation minimum diameter <6 mm. There were 13 patients with aortic aneurysms, with a cumulative incidence of 6.3% at late follow-up. Coarctation stenting is effective at maintaining obstruction relief up to 60 months postimplant with reduction in the number of patients requiring antihypertensive medication. However, an increase in-stent fractures and reinterventions were observed between medium and long-term follow-up. Covered stents appear to confer some protection from the development of stent fractures but do not provide complete protection from late aneurysm formation. URL: https://www.clinicaltrials.gov; Unique identifiers: NCT00552812 and NCT01278303.

Attenuated Microcirculation in Small Metastatic Tumors in Murine Liver.

Metastatic cancer disease is the major cause of death in cancer patients. Because those small secondary tumors are clinically hardly detectable in their early stages, little is known about drug biodistribution and permeation into those metastatic tumors potentially contributing to insufficient clinical success against metastatic disease. Our recent studies indicated that breast cancer liver metastases may have compromised perfusion of intratumoral capillaries hindering the delivery of therapeutics for yet unknown reasons. To understand the microcirculation of small liver metastases, we have utilized computational simulations to study perfusion and oxygen concentration fields in and around the metastases smaller than 700 µm in size at the locations of portal vessels, central vein, and liver lobule acinus. Despite tumor vascularization, the results show that blood flow in those tumors can be substantially reduced indicating the presence of inadequate blood pressure gradients across tumors. A low blood pressure may contribute to the collapsed intratumoral capillary lumen limiting tumor perfusion that phenomenologically corroborates with our previously published in vivo studies. Tumors that are smaller than the liver lobule size and originating at different lobule locations may possess a different microcirculation environment and tumor perfusion. The acinus and portal vessel locations in the lobule were found to be the most beneficial to tumor growth based on tumor access to blood flow and intratumoral oxygen. These findings suggest that microcirculation states of small metastatic tumors can potentially contribute to physiological barriers preventing efficient delivery of therapeutic substances into small tumors.

AGE-SPECIFIC ACUTE CHANGES IN CAROTID-FEMORAL PULSE WAVE VELOCITY DURING HEAD-UP TILTING

Objective: Hydrostatic blood pressure (BP) gradient following changes in body posture may generate concomitant, age-dependent, increases in aortic stiffness. We analyzed the relationship between BP gradient, measured during head-up body tilting, and related changes in carotid-femoral pulse wave velocity (cf-PWV) at different age ranges, with the aim to separate the BP-dependent and BP-independent components of cf-PWV. Design and method: cf-PWV and other hemodynamic parameters were measured in 30 healthy individuals during head-up tilting at 0°, 30° and 60°. BP was taken at the upper arm, constantly kept at heart level. Aortic BP was reconstructed from radial tonometry (SphygmoCor). Stiffness index β0 was estimated at 0° (Spronck et al, J Hypertens 2017;35:98–104). We assumed that: from MRI studies (Sugawara et al, Am J Hypertens. 2016;29:1237–1244), the effective cf-PWV travel distance (ETD, 80% of straight carotid-to-femoral distance) begins at heart level; the change in DBP along the aorta is predictable from the hydrostatic pressure gradient (0.73 mmHg/cm, Gavish et al, J Hypertens. 2011;29:2099–2104); cf-PWV and hydrostatic pressure relate linearly, hence predicted cf-PWV can be calculated as the average of aortic (using β0 and aortic DBP) and femoral (using β0 and femoral DBP, corresponding to aortic DBP + (ETD x sin(α)∗0.73)) PWVs. Results: cf-PWV and peripheral SBP increases during head-up body tilting were different between age groups, being more pronounced in the “old” (&gt;45 years) vs “young” group (both p for interaction &lt;0.05), whereas both central and peripheral DBP changes were not influenced by age (Figure, panel left). Central SBP was not affected by tilt angles. When cf-PWV gradient measured by applanation tonometry (observed), was compared with that predicted from estimated DBP gradient (predicted), the difference in observed-vs-predicted PWV gradient increased non-linearly as a function of age (R2 for quadratic trend=0.38, p &lt; 0.01, p vs linear=0.04, Figure panel right). Conclusions: Under a hydrostatic pressor gradient, the pulse wave travelling along the aorta undergoes positive acceleration which, for any given pressor change, increases non-linearly as a function of age. The evaluation of aortic pulse wave acceleration induced by pressor gradient may be of clinical relevance as a marker of vascular ageing.

Investigation of Apnea Testing During Brain Death Determination in China.

Apnea testing (AT) is one of the key steps for brain death (BD) diagnosis and confirmation. However, the completion rate of AT is not well in China. The aim of this study was to investigate the completion rates of the AT during BD determination in China and analyze the determinant factors. We reviewed and analyzed potential BD patients registered in our database from 2013 to 2019. The patients were divided into those with completed and aborted AT. Preconditions and organ function status were compared between the two groups. A total of 1,531 (1,301 adults and 230 pediatrics) cases of potential BD were extracted, and BD determination was performed 2,185 and 377 times in adults and pediatrics respectively. The nonperformance and aborted rates of AT were 12.2% and 34.5% in adults, and 11.7% and 44.4% in pediatrics respectively. Compared with the completed group, the aborted group had a lower PaO2, systolic blood pressure, PaO2/FiO2 ratios, and higher alveolar-arterial (A-a) gradient both in adults and pediatrics, and higher PaCO2 and higher heart rates in adults. PaO2 and A-a gradient had higher predictive efficacy for AT completion in both adults and pediatrics. The implementation and completion rates of AT are not ideal in China. PaO2 and A-a gradient are important factors for the successful completion of AT and should be optimized before AT.

Clinical and imaging characteristics of isolated subclavian artery in pediatric patients

ObjectivesTo describe clinical and imaging characteristics of an isolated subclavian artery (ISA) in pediatric patients. BackgroundISA is a rare congenital aortic arch anomaly defined as a loss of connection between the subclavian artery and aorta. The clinical manifestations and complications of ISA in children are unclear. MethodsThis retrospective study included clinical and imaging data of ISA patients younger than 18 years whose data were recorded in the electronic radiology database during January 2006–August 2019. ResultsOf 102 enrolled patients, 59 had been diagnosed in the first year of life. The majority of the patients also had congenital heart diseases, of which tetralogy of Fallot was the most common. The vertebral artery and collateral branch of the descending aorta served as blood flow supplies in 94 and 8 patients with ISA, respectively, as confirmed using computed tomography or magnetic resonance imaging. However, the blood supply did not influence the development of ISA. Eleven patients exhibited mild or moderate stenosis of the ISA, although only two exhibited coldness or a blood pressure gradient in the upper extremities. These two symptomatic patients also presented with patent ductus arteriosus, and this association was significant (P = 0.008). ConclusionISA management is often determined based on symptoms and associated congenital heart diseases. The ISA is prone to stenosis in patients with ipsilateral patent ductus arteriosus. We recommend early surgical ligation or percutaneous closure of the ductus arteriosus in patients with ISA.

Human ophthalmic artery as a sensor for non-invasive intracranial pressure monitoring: numerical modeling and in vivo pilot study

Intracranial pressure (ICP) monitoring is important in managing neurosurgical, neurological, and ophthalmological patients with open-angle glaucoma. Non-invasive two-depth transcranial Doppler (TCD) technique is used in a novel method for ICP snapshot measurement that has been previously investigated prospectively, and the results showed clinically acceptable accuracy and precision. The aim of this study was to investigate possibility of using the ophthalmic artery (OA) as a pressure sensor for continuous ICP monitoring. First, numerical modeling was done to investigate the possibility, and then a pilot clinical study was conducted to compare two-depth TCD-based non-invasive ICP monitoring data with readings from an invasive Codman ICP microsensor from patients with severe traumatic brain injury. The numerical modeling showed that the systematic error of non-invasive ICP monitoring was < 1.0 mmHg after eliminating the intraorbital and blood pressure gradient. In a clinical study, a total of 1928 paired data points were collected, and the extreme data points of measured differences between invasive and non-invasive ICP were − 3.94 and 4.68 mmHg (95% CI − 2.55 to 2.72). The total mean and SD were 0.086 ± 1.34 mmHg, and the correlation coefficient was 0.94. The results show that the OA can be used as a linear natural pressure sensor and that it could potentially be possible to monitor the ICP for up to 1 h without recalibration.