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European Journal of Mechanics. B, Fluids 2024This study aims at clarifying the relation between the oscillatory flow of cerebrospinal fluid (CSF) in the cerebral aqueduct, a narrow conduit connecting the third and...
This study aims at clarifying the relation between the oscillatory flow of cerebrospinal fluid (CSF) in the cerebral aqueduct, a narrow conduit connecting the third and fourth ventricles, and the corresponding interventricular pressure difference. Dimensional analysis is used in designing an anatomically correct scaled model of the aqueduct flow, with physical similarity maintained by adjusting the flow frequency and the properties of the working fluid. The time-varying pressure difference across the aqueduct corresponding to a given oscillatory flow rate is measured in parametric ranges covering the range of flow conditions commonly encountered in healthy subjects. Parametric dependences are delineated for the time-averaged pressure fluctuations and for the phase lag between the transaqueductal pressure difference and the flow rate, both having clinical relevance. The results are validated through comparisons with predictions obtained with a previously derived computational model. The parametric quantification in this study enables the derivation of a simple formula for the relation between the transaqueductal pressure and the stroke volume. This relationship can be useful in the quantification of transmantle pressure differences based on non-invasive magnetic-resonance-velocimetry measurements of aqueduct flow for investigation of CSF-related disorders.
PubMed: 38770034
DOI: 10.1016/j.euromechflu.2024.01.010 -
JACC. Case Reports May 2024Fontan pathway obstruction is a potentially serious complication characterized by an anatomical or functional narrowing anywhere in the cavo-pulmonary pathways. Here, we...
Fontan pathway obstruction is a potentially serious complication characterized by an anatomical or functional narrowing anywhere in the cavo-pulmonary pathways. Here, we report the first case in the literature where an innovative Fontan conduit rehabilitation procedure with intravascular lithotripsy was used achieving a dramatic increase in the pathway size.
PubMed: 38708431
DOI: 10.1016/j.jaccas.2024.102296 -
Journal of Clinical Medicine Apr 2024: The surgical treatment of chronic limb-threatening ischemia and optimal conduit choice are extensively debated. The presence of suboptimal autologous material, such as...
: The surgical treatment of chronic limb-threatening ischemia and optimal conduit choice are extensively debated. The presence of suboptimal autologous material, such as varicosities or venous aneurysms, might impair long-term outcomes. Therefore, kink-resistant external supports have been advocated in the recent literature to improve the conduit quality and outcomes. This study analyzes the FRAME external support in venous ectasic grafts in patients with chronic limb-threatening ischemia. : From September 2017 to September 2023, a total of sixteen patients underwent CLTI surgery with FRAME external support for venous grafts. The inclusion criteria for FRAME applications were varicose or ectasic autologous material with a diameter ≥ 4.5 and ≤ 8 mm in an isolated segment or in the entire vein and a higher risk of bypass extrinsic compression (e.g., extra-anatomical venous bypass course). : Technical success and intraoperative patency were achieved in all cases. At 30 days, the limb salvage and survival rates were 100%. The primary bypass patency was 93.7% due to an early graft occlusion. No graft infection was registered. In one case, dehiscence of the surgical wound was treated by surgical debridement and antibiotic therapy. Minor amputation was required in four patients. Over a median follow-up of 32 months, two occlusions were observed; one was treated with reoperation and the other with major amputation. The primary patency was 68.7% and the assisted primary patency was 75%. Limb salvage rates observed during the entire follow-up period were 87.5%. No graft infections or dilatation of the reinforced veins were registered. : For patients with CLTI undergoing infrainguinal bypass, satisfactory results in terms of patency and limb salvage rates were achieved using the autologous venous material, even if ectasic or varicose, with the vascular external support FRAME.
PubMed: 38610860
DOI: 10.3390/jcm13072095 -
Journal of the Mechanical Behavior of... Jun 2024Despite polyester vascular grafts being routinely used in life-saving aortic aneurysm surgeries, they are less compliant than the healthy, native human aorta. This...
Despite polyester vascular grafts being routinely used in life-saving aortic aneurysm surgeries, they are less compliant than the healthy, native human aorta. This mismatch in mechanical behaviour has been associated with disruption of haemodynamics contributing to several long-term cardiovascular complications. Moreover, current fabrication approaches mean that opportunities to personalise grafts to the individual anatomical features are limited. Various modifications to graft design have been investigated to overcome such limitations; yet optimal graft functionality remains to be achieved. This study reports on the development and characterisation of an alternative vascular graft material. An alginate:PEGDA (AL:PE) interpenetrating polymer network (IPN) hydrogel has been produced with uniaxial tensile tests revealing similar strength and stiffness (0.39 ± 0.05 MPa and 1.61 ± 0.19 MPa, respectively) to the human aorta. Moreover, AL:PE tubular conduits of similar geometrical dimensions to segments of the aorta were produced, either via conventional moulding methods or stereolithography (SLA) 3D-printing. While both fabrication methods successfully demonstrated AL:PE hydrogel production, SLA 3D-printing was more easily adaptable to the fabrication of complex structures without the need of specific moulds or further post-processing. Additionally, most 3D-printed AL:PE hydrogel tubular conduits sustained, without failure, compression up to 50% their outer diameter and returned to their original shape upon load removal, thereby exhibiting promising behaviour that could withstand pulsatile pressure in vivo. Overall, these results suggest that this AL:PE IPN hydrogel formulation in combination with 3D-printing, has great potential for accelerating progress towards personalised and mechanically-matched aortic grafts.
Topics: Humans; Printing, Three-Dimensional; Blood Vessel Prosthesis; Aortic Aneurysm; Aorta; Hydrogels
PubMed: 38588633
DOI: 10.1016/j.jmbbm.2024.106531 -
Journal of Endovascular Therapy : An... Apr 2024To assess the feasibility and safety of intravascular lithotripsy (IVL) for enabling transfemoral abdominal (EVAR), thoracic (TEVAR), and thoracoabdominal (BEVAR)...
PURPOSE
To assess the feasibility and safety of intravascular lithotripsy (IVL) for enabling transfemoral abdominal (EVAR), thoracic (TEVAR), and thoracoabdominal (BEVAR) endovascular aneurysm repair in patients with narrow and calcified iliac arteries.
MATERIALS AND METHODS
Consecutive patients treated with IVL for severe calcified and narrowed iliac access before EVAR, TEVAR, or BEVAR between November 2020 and June 2022 were retrospectively evaluated. All anatomical iliac characteristics were acquired by multi-planar reconstruction of preoperative computed tomography angiography (CTA). The hostility of the vascular accesses was classified based on Peripheral Arterial Calcium Scoring System (PACSS) and calcified access severity score (CASS), a new score considering both anatomical (calcium grade and length, minimum lumen diameter [MLD], and tortuosity index) and aortic stent-graft (SG/MLD index) parameters. Primary endpoint was technical success defined as successful aortic endograft delivery and deployment without iliac rupture. Freedom from complications and primary patency were additionally analyzed.
RESULTS
Twenty-eight iliac axes were treated with IVL (8 bilateral) in 20 patients (mean age 74.5±6.7 years) with a mean follow-up of 26.5±6.2 (range 17-36) months. Ten patients underwent EVAR: 3 TEVAR, and 7 BEVAR procedures. In 14 patients (70%), aneurysm disease was associated with symptomatic aorto-iliac occlusive disease (AIOD), with Rutherford class III to IV. The PACSS was grade IV in 89% of the cases and the CASS (mean 14±2) was grade III to IV in all cases. The stent-graft (SG) outer diameter (5.60±1.65 mm) was significantly larger by 50% than MLD (3.96±1.20 mm), with an SG/MLD index of 1.50±0.51 (p<0.001). Technical success was 100%. No dissection, rupture, or distal embolization occurred. One (3.4%) bail-out stenting was necessary as endoconduit after IVL treatment. One month CTA showed that postoperative luminal gain increased by 93% (p<0.001). An improvement of 2 Rutherford classes occurred in all AIOD patients with a primary patency of 100% at last follow-up.
CONCLUSIONS
This study shows the safety and feasibility of IVL as a valuable option to treat narrow and calcified iliac arteries to facilitate endograft delivery. Further studies will be useful to confirm these results.
CLINICAL IMPACT
In this article, the use of intravascular iliac artery lithotripsy to facilitate aortic endograft delivery is explored. The presence of iliac severe calcifications still represents a contraindication for aortic endovascular repair. Intravascular lithotripsy increases the feasibility and safety of endovascular aortic procedures, facilitating endograft delivery and reducing the risk of iliac rupture and/or dissections by improving vessel compliance and luminal gain. This novel vessel preparation could be an alternative to "paving and cracking" and/or iliac conduits. This study describes a new score to classify the severity of iliac calcifications, considering anatomical parameters and the profile of aortic endografts delivery system.
PubMed: 38561973
DOI: 10.1177/15266028241241246 -
Journal of Vascular Surgery Cases and... Jun 2024Renal artery access might not always be achieved due to anatomical reasons during the deployment of a branched stent graft in thoracoabdominal or juxtarenal abdominal...
Renal artery access might not always be achieved due to anatomical reasons during the deployment of a branched stent graft in thoracoabdominal or juxtarenal abdominal aortic aneurysms. Renal perfusion is maintained through the aneurysm sac until the iliac limbs are deployed. To preserve renal perfusion, a branched iliac limb would be needed. Such limbs with a side branch, a narrow (12-14 mm) proximal end, and a wide (16-20 mm) distal end are not commercially available. Due to the nature of their deployment mechanism, Gore Excluder distal limbs (W.L. Gore & Associates) have been used outside the instructions for use in reversed position. A traditional Gore Excluder main body can be reversed; however, the smallest proximal diameter is 23 mm, which could be too large to be deployed in a typically 16- to 18-mm common iliac artery. However, the smallest Gore Excluder Conformable endoprosthesis (W.L. Gore & Associates, Inc) main body is 20 mm in diameter, and the distal limb is 14.5 mm. This allows for a perfect fit when deployed in reversed position between an 11-mm unibody limb (Cook Medical Inc) and the common iliac artery, resulting in access to the renal artery from the side branch. We used a Gore Excluder Conformable main body graft in two such cases successfully. In these two patients, the iliac limbs and renal artery have stayed patent during a follow-up of 24 and 3 months. A Gore Excluder Conformable graft can be deployed in reversed position, using it as a conduit between the branched stent graft limb, common iliac artery, and renal artery.
PubMed: 38510095
DOI: 10.1016/j.jvscit.2024.101452 -
Structural Heart : the Journal of the... Mar 2024Transcatheter mitral valve-in-valve (MViV) replacement has emerged as an alternative to redo mitral valve (MV) surgery for the management of failed bioprosthetic MVs....
BACKGROUND
Transcatheter mitral valve-in-valve (MViV) replacement has emerged as an alternative to redo mitral valve (MV) surgery for the management of failed bioprosthetic MVs. The degree of cardiac remodeling assessed by echocardiography has been shown to have prognostic implications in degenerative mitral regurgitation patients undergoing MV surgery. The impact of transcatheter MViV in patients with degenerative bioprosthetic MV failure on cardiac remodeling and its associated prognosis remains undescribed.
OBJECTIVES
The aim of this study is to describe the early anatomic and functional changes of the left-sided chambers and right ventricle by echocardiography posttranscatheter MViV intervention and their impact on mortality outcomes. Additionally, we sought to analyze the outcome of heart failure in bioprosthetic MV failure patients undergoing transcatheter MViV replacement.
METHODS
We analyzed consecutive patients undergoing MViV intervention for symptomatic bioprosthetic MV failure. Echocardiograms before intervention and within 100 days postintervention were analyzed. A chart review was performed to obtain baseline characteristics, follow-up visits, 30-day heart failure and 1-year all-cause mortality outcomes.
RESULTS
A total of 62 patients (mean age 69 ± 13 years, 61% male) were included in the study. Most patients were undergoing MViV intervention for prosthetic mitral stenosis n = 48 (77.4%) and the rest for mitral regurgitation or mixed disease. Compared with baseline, significant reductions were observed in median left atrial volume (LAV; 103 [81-129] ml vs. 95.2 [74.5-117.5] ml, < 0.01) and mean (SD) left atrial conduit strain (9.1% ± 5.2% vs. 10.8% ± 4.8%, = 0.039) within 100 days postintervention. Early reduction in right ventricular free wall global longitudinal strain and fractional area change also occurred postintervention. No significant change in left ventricular chamber dimensions or ejection fraction was observed. During the 1-year follow up period, 5 (8%) patients died. While baseline LAV was not associated with 1-year all-cause mortality (OR 0.98 CI 0.95-1.01; = 0.27), a change in LAV in the follow up period was associated with all-cause mortality at 1 year (OR 1.06 CI 1.01-1.12; = 0.023). At 30 days postintervention, 65% of patients had an improvement in their New York Heart Association functional class.
CONCLUSION
In this retrospective study of patients undergoing transcatheter MViV intervention for failed bioprosthetic MVs, early reverse remodeling of the left atrium occurs within 100 days postintervention and reduction in LAV is associated with reduced all-cause mortality at 1 year. In addition, there is significant improvement in heart failure symptoms at 30 days following intervention but further investigation into the longitudinal remodeling changes and long-term outcomes is needed.
PubMed: 38481712
DOI: 10.1016/j.shj.2023.100264 -
JTCVS Techniques Feb 2024The configuration of the gastric conduit after esophagectomy can lead to chronic gastrointestinal and respiratory issues. Surgical revision of the gastric conduit has...
INTRODUCTION
The configuration of the gastric conduit after esophagectomy can lead to chronic gastrointestinal and respiratory issues. Surgical revision of the gastric conduit has been described in small series but appears to be infrequently used. We investigated outcomes of revising dilated or redundant conduit in patients with severe quality-of-life issues.
METHODS
We identified all patients from 2016 to 2022 at our institution who underwent gastric conduit revision after previous esophagectomy either at our or another institution. Chart review was performed to assess prerevision course and perioperative outcomes. Pre- and postrevision imaging was compared for all patients to assess the impact of surgery on anatomic configuration. Patient-reported gastrointestinal and respiratory issues before and after surgery were examined.
RESULTS
The use of right thoracotomy combined with laparotomy to reduce redundancy and improve gastric emptying was performed in 8 patients. The symptoms necessitating reoperation included intolerance to oral intake and poor gastric emptying associated with both acute and chronic aspiration episodes. The median length of stay was 8 [4, 25] days, and there were no perioperative mortalities. Seven (87.5%) patients were tolerating oral intake at discharge. All patients had improvement in their prerevision symptoms on follow-up.
CONCLUSIONS
Gastric conduit revision can improve severe postesophagectomy gastrointestinal and respiratory symptoms in patients with dilated/redundant conduits with limited perioperative morbidity.
PubMed: 38351992
DOI: 10.1016/j.xjtc.2023.11.006 -
Surgical Case Reports Feb 2024In patients with retrosternal neo-esophageal conduit after right thoracotomy, the approach to cardiac surgery could be challenging. Particularly, in patients with...
BACKGROUND
In patients with retrosternal neo-esophageal conduit after right thoracotomy, the approach to cardiac surgery could be challenging. Particularly, in patients with infective endocarditis, there is a risk of injury to the conduit through standard median sternotomy. Moreover, right lung adhesions could be predicted. Herein, we present a case of successful mitral valve repair in a patient with infective endocarditis through a redo right thoracotomy after esophageal reconstruction.
CASE PRESENTATION
A 66-year-old male patient was diagnosed with infective endocarditis and a large anterior mitral leaflet vegetation after a previous esophageal reconstruction via right thoracotomy for esophageal cancer. Due to the retrosternal esophageal reconstruction, we performed a mitral valve repair through a redo right thoracotomy. After resecting the vegetation, the defect was closed with a fresh autologous pericardial patch. Mitral valve annuloplasty was performed. Postoperatively, antibiotics controlled the infection. The patient was discharged on postoperative day 30.
CONCLUSIONS
Successful mitral valve repair was performed for infective endocarditis through a redo right thoracotomy after esophageal reconstruction.
PubMed: 38332244
DOI: 10.1186/s40792-024-01836-7 -
Archives of Medical Sciences.... 2023Choosing appropriate bypass conduits is important in the consideration of long-term outcomes after surgical revascularization. When deciding on a grafting strategy,...
Choosing appropriate bypass conduits is important in the consideration of long-term outcomes after surgical revascularization. When deciding on a grafting strategy, attention should be given to technical, anatomic, and angiographic determinants of conduit properties, as well as the clinical characteristics of the patient. The aim of the study was to present a current review of available choices of conduits in coronary artery bypass surgery. To date, only 4 conduits have proven to be effective: the saphenous vein (SVG), the internal mammary arteries (IMAs), the radial artery (RA), and the right gastroepiploic artery (RGEA). The IMA has unique biological properties that confer protection to intimal growth and atherosclerotic plaque formation, making it the conduit of choice for coronary artery bypass grafting. SVG exhibits a lower patency rate than those of IMAs. The RGEA allows revascularization of the inferior wall but is less commonly used, given that it is more prone to spasms.
PubMed: 38089163
DOI: 10.5114/amsad/170215