Author:

Ann Biomed Eng. 2026 Jun 9. doi: 10.1007/s10439-026-04207-5. Online ahead of print.

ABSTRACT

BACKGROUND: The biomechanical performance of bileaflet transcatheter mitral valves (TMVs) depends on complex interactions between leaflet material behavior and stent design. However, the contributions of leaflet materials and constitutive models, stent materials, and stent geometry to valve function and durability remain poorly understood.

METHODS: A parametric finite element study was conducted using a CAD model of a bileaflet TMV subjected to physiological pressure loading. Five leaflet material models were evaluated: 3 glutaraldehyde-fixed tissues-bovine pericardium (BP; FBP1, FBP2) and porcine pericardium (PP; FPP)-and 2 unfixed tissues-bovine (UBP) and porcine pericardium (UPP). BP was modeled as a linear elastic (FBP1) and Ogden (FBP2). Each was paired with 2 stent materials, cobalt chromium (CoCr) and nitinol, and 3 stent cell densities (low, medium, high), yielding 30 configurations. Von Mises stresses and relative leaflet opening were quantified.

RESULTS: UPP achieved the largest opening (30-32%) with the lowest leaflet 99th percentile stresses (0.048-0.050 MPa), while FBP1 produced the smallest opening (8-9%) and highest leaflet stresses (0.077-0.078 MPa). Leaflet 99th percentile stress was strongly inversely correlated with valve opening (Spearman r=-0.9, p<0.01). Stent material had a negligible effect on valve opening but affected stent stress notably, with nitinol exhibiting about 2-3 orders of magnitude lower stresses compared to CoCr. Increasing stent cell density improved stress distribution with only a modest reduction in opening.

CONCLUSION: Leaflet material model was the primary determinant of bileaflet TMV biomechanical performance, whereas stent material and cell density exerted secondary but meaningful effects. These findings offer insights that may guide the design of more optimized TMV replacement devices.

PMID:42262702 | DOI:10.1007/s10439-026-04207-5

Ann Biomed Eng. 2026 Jun 9. doi: 10.1007/s10439-026-04207-5. Online ahead of print.

ABSTRACT

BACKGROUND: The biomechanical performance of bileaflet transcatheter mitral valves (TMVs) depends on complex interactions between leaflet material behavior and stent design. However, the contributions of leaflet materials and constitutive models, stent materials, and stent geometry to valve function and durability remain poorly understood.

METHODS: A parametric finite element study was conducted using a CAD model of a bileaflet TMV subjected to physiological pressure loading. Five leaflet material models were evaluated: 3 glutaraldehyde-fixed tissues-bovine pericardium (BP; FBP1, FBP2) and porcine pericardium (PP; FPP)-and 2 unfixed tissues-bovine (UBP) and porcine pericardium (UPP). BP was modeled as a linear elastic (FBP1) and Ogden (FBP2). Each was paired with 2 stent materials, cobalt chromium (CoCr) and nitinol, and 3 stent cell densities (low, medium, high), yielding 30 configurations. Von Mises stresses and relative leaflet opening were quantified.

RESULTS: UPP achieved the largest opening (30-32%) with the lowest leaflet 99th percentile stresses (0.048-0.050 MPa), while FBP1 produced the smallest opening (8-9%) and highest leaflet stresses (0.077-0.078 MPa). Leaflet 99th percentile stress was strongly inversely correlated with valve opening (Spearman r=-0.9, p<0.01). Stent material had a negligible effect on valve opening but affected stent stress notably, with nitinol exhibiting about 2-3 orders of magnitude lower stresses compared to CoCr. Increasing stent cell density improved stress distribution with only a modest reduction in opening.

CONCLUSION: Leaflet material model was the primary determinant of bileaflet TMV biomechanical performance, whereas stent material and cell density exerted secondary but meaningful effects. These findings offer insights that may guide the design of more optimized TMV replacement devices.

PMID:42262702 | DOI:10.1007/s10439-026-04207-5

Ann Biomed Eng. 2026 Jun 9. doi: 10.1007/s10439-026-04207-5. Online ahead of print.

ABSTRACT

BACKGROUND: The biomechanical performance of bileaflet transcatheter mitral valves (TMVs) depends on complex interactions between leaflet material behavior and stent design. However, the contributions of leaflet materials and constitutive models, stent materials, and stent geometry to valve function and durability remain poorly understood.

METHODS: A parametric finite element study was conducted using a CAD model of a bileaflet TMV subjected to physiological pressure loading. Five leaflet material models were evaluated: 3 glutaraldehyde-fixed tissues-bovine pericardium (BP; FBP1, FBP2) and porcine pericardium (PP; FPP)-and 2 unfixed tissues-bovine (UBP) and porcine pericardium (UPP). BP was modeled as a linear elastic (FBP1) and Ogden (FBP2). Each was paired with 2 stent materials, cobalt chromium (CoCr) and nitinol, and 3 stent cell densities (low, medium, high), yielding 30 configurations. Von Mises stresses and relative leaflet opening were quantified.

RESULTS: UPP achieved the largest opening (30-32%) with the lowest leaflet 99th percentile stresses (0.048-0.050 MPa), while FBP1 produced the smallest opening (8-9%) and highest leaflet stresses (0.077-0.078 MPa). Leaflet 99th percentile stress was strongly inversely correlated with valve opening (Spearman r=-0.9, p<0.01). Stent material had a negligible effect on valve opening but affected stent stress notably, with nitinol exhibiting about 2-3 orders of magnitude lower stresses compared to CoCr. Increasing stent cell density improved stress distribution with only a modest reduction in opening.

CONCLUSION: Leaflet material model was the primary determinant of bileaflet TMV biomechanical performance, whereas stent material and cell density exerted secondary but meaningful effects. These findings offer insights that may guide the design of more optimized TMV replacement devices.

PMID:42262702 | DOI:10.1007/s10439-026-04207-5

Ann Biomed Eng. 2026 Jun 9. doi: 10.1007/s10439-026-04207-5. Online ahead of print.

ABSTRACT

BACKGROUND: The biomechanical performance of bileaflet transcatheter mitral valves (TMVs) depends on complex interactions between leaflet material behavior and stent design. However, the contributions of leaflet materials and constitutive models, stent materials, and stent geometry to valve function and durability remain poorly understood.

METHODS: A parametric finite element study was conducted using a CAD model of a bileaflet TMV subjected to physiological pressure loading. Five leaflet material models were evaluated: 3 glutaraldehyde-fixed tissues-bovine pericardium (BP; FBP1, FBP2) and porcine pericardium (PP; FPP)-and 2 unfixed tissues-bovine (UBP) and porcine pericardium (UPP). BP was modeled as a linear elastic (FBP1) and Ogden (FBP2). Each was paired with 2 stent materials, cobalt chromium (CoCr) and nitinol, and 3 stent cell densities (low, medium, high), yielding 30 configurations. Von Mises stresses and relative leaflet opening were quantified.

RESULTS: UPP achieved the largest opening (30-32%) with the lowest leaflet 99th percentile stresses (0.048-0.050 MPa), while FBP1 produced the smallest opening (8-9%) and highest leaflet stresses (0.077-0.078 MPa). Leaflet 99th percentile stress was strongly inversely correlated with valve opening (Spearman r=-0.9, p<0.01). Stent material had a negligible effect on valve opening but affected stent stress notably, with nitinol exhibiting about 2-3 orders of magnitude lower stresses compared to CoCr. Increasing stent cell density improved stress distribution with only a modest reduction in opening.

CONCLUSION: Leaflet material model was the primary determinant of bileaflet TMV biomechanical performance, whereas stent material and cell density exerted secondary but meaningful effects. These findings offer insights that may guide the design of more optimized TMV replacement devices.

PMID:42262702 | DOI:10.1007/s10439-026-04207-5

Cureus. 2026 Apr 29;18(4):e107945. doi: 10.7759/cureus.107945. eCollection 2026 Apr.

ABSTRACT

Ventricular septal rupture (VSR) is a rare but catastrophic mechanical complication of acute myocardial infarction, even in the contemporary reperfusion era. Although early reperfusion strategies have significantly reduced its incidence, they do not completely eliminate the risk. We report the case of a 76-year-old man with a history of hypertension and no prior structural heart disease who presented with an anterior ST-elevation myocardial infarction (STEMI). He received tenecteplase 2 hours and 37 minutes after symptom onset and was subsequently referred for routine percutaneous coronary intervention (PCI), during which a stent was implanted in the left anterior descending (LAD) artery. During in-hospital monitoring, a new harsh holosystolic murmur was detected. Transthoracic echocardiography revealed an 11-mm interventricular septal defect with left-to-right shunting, which was confirmed by color and spectral Doppler. Despite this mechanical complication, the patient remained hemodynamically stable and did not require vasopressor support. He underwent successful surgical repair using an infarct exclusion technique with a bovine pericardial patch. The postoperative course was favorable, with no need for mechanical circulatory support, extubation within the first 12 hours, no requirement for high-dose vasoactive amines, and no residual shunt on follow-up echocardiography. He was discharged home with outpatient follow-up. This case highlights that post-infarction VSR may occur despite timely pharmaco-invasive reperfusion, particularly in anterior STEMI, and underscores the importance of continued clinical vigilance even after apparently successful reperfusion. Early recognition through physical examination and echocardiography, together with prompt multidisciplinary management, may allow for favorable outcomes in selected patients.

PMID:42220791 | PMC:PMC13220294 | DOI:10.7759/cureus.107945

Ann Biomed Eng. 2026 Jun 9. doi: 10.1007/s10439-026-04207-5. Online ahead of print.

ABSTRACT

BACKGROUND: The biomechanical performance of bileaflet transcatheter mitral valves (TMVs) depends on complex interactions between leaflet material behavior and stent design. However, the contributions of leaflet materials and constitutive models, stent materials, and stent geometry to valve function and durability remain poorly understood.

METHODS: A parametric finite element study was conducted using a CAD model of a bileaflet TMV subjected to physiological pressure loading. Five leaflet material models were evaluated: 3 glutaraldehyde-fixed tissues-bovine pericardium (BP; FBP1, FBP2) and porcine pericardium (PP; FPP)-and 2 unfixed tissues-bovine (UBP) and porcine pericardium (UPP). BP was modeled as a linear elastic (FBP1) and Ogden (FBP2). Each was paired with 2 stent materials, cobalt chromium (CoCr) and nitinol, and 3 stent cell densities (low, medium, high), yielding 30 configurations. Von Mises stresses and relative leaflet opening were quantified.

RESULTS: UPP achieved the largest opening (30-32%) with the lowest leaflet 99th percentile stresses (0.048-0.050 MPa), while FBP1 produced the smallest opening (8-9%) and highest leaflet stresses (0.077-0.078 MPa). Leaflet 99th percentile stress was strongly inversely correlated with valve opening (Spearman r=-0.9, p<0.01). Stent material had a negligible effect on valve opening but affected stent stress notably, with nitinol exhibiting about 2-3 orders of magnitude lower stresses compared to CoCr. Increasing stent cell density improved stress distribution with only a modest reduction in opening.

CONCLUSION: Leaflet material model was the primary determinant of bileaflet TMV biomechanical performance, whereas stent material and cell density exerted secondary but meaningful effects. These findings offer insights that may guide the design of more optimized TMV replacement devices.

PMID:42262702 | DOI:10.1007/s10439-026-04207-5

Ann Biomed Eng. 2026 Jun 9. doi: 10.1007/s10439-026-04207-5. Online ahead of print.

ABSTRACT

BACKGROUND: The biomechanical performance of bileaflet transcatheter mitral valves (TMVs) depends on complex interactions between leaflet material behavior and stent design. However, the contributions of leaflet materials and constitutive models, stent materials, and stent geometry to valve function and durability remain poorly understood.

METHODS: A parametric finite element study was conducted using a CAD model of a bileaflet TMV subjected to physiological pressure loading. Five leaflet material models were evaluated: 3 glutaraldehyde-fixed tissues-bovine pericardium (BP; FBP1, FBP2) and porcine pericardium (PP; FPP)-and 2 unfixed tissues-bovine (UBP) and porcine pericardium (UPP). BP was modeled as a linear elastic (FBP1) and Ogden (FBP2). Each was paired with 2 stent materials, cobalt chromium (CoCr) and nitinol, and 3 stent cell densities (low, medium, high), yielding 30 configurations. Von Mises stresses and relative leaflet opening were quantified.

RESULTS: UPP achieved the largest opening (30-32%) with the lowest leaflet 99th percentile stresses (0.048-0.050 MPa), while FBP1 produced the smallest opening (8-9%) and highest leaflet stresses (0.077-0.078 MPa). Leaflet 99th percentile stress was strongly inversely correlated with valve opening (Spearman r=-0.9, p<0.01). Stent material had a negligible effect on valve opening but affected stent stress notably, with nitinol exhibiting about 2-3 orders of magnitude lower stresses compared to CoCr. Increasing stent cell density improved stress distribution with only a modest reduction in opening.

CONCLUSION: Leaflet material model was the primary determinant of bileaflet TMV biomechanical performance, whereas stent material and cell density exerted secondary but meaningful effects. These findings offer insights that may guide the design of more optimized TMV replacement devices.

PMID:42262702 | DOI:10.1007/s10439-026-04207-5

Oper Neurosurg. 2026 Jun 3. doi: 10.1227/ons.0000000000002083. Online ahead of print.

ABSTRACT

BACKGROUND AND OBJECTIVES: Circumferential defects of the dural sleeve of exiting lumbar nerve roots may occur after incidental durotomy, trauma, or deliberate opening of the root cuff during resection of nerve sheath tumors. Standard onlay duraplasty can control cerebrospinal fluid (CSF) leakage but does not restore the tubular dural-epineural conduit. We describe a collagen-matrix cuff technique for root sleeve reconstruction and report our initial institutional experience.

METHODS: This single-center, retrospective case series includes 9 consecutive reconstructions performed between January 2022 and October 2025 for intraoperatively recognized circumferential defects of exiting lumbar nerve root sleeves not amenable to safe primary suturing. The cohort comprised 6 iatrogenic root sleeve defects occurring during elective lumbar procedures (including instrumented and noninstrumented decompressive and/or stabilizing surgeries), 2 post-traumatic cases, and 1 elective tumor case presented as the illustrative case (L3 nerve root ganglioneuroma resection). Clinical records, intraoperative notes, and imaging were reviewed retrospectively. Minimum clinical and MRI follow-up was 6 months for all patients. Adjunctive lumbar drainage was used in one iatrogenic case.

RESULTS: In all cases, a bovine pericardium-derived collagen matrix was prehydrated, tailored, positioned under the root, sutured proximally to the dural margin at the root axilla, and wrapped to form a tubular cuff bridging the dural sac to the epineural segment, with distal reinforcement using fat and fibrin sealant. No patient required reoperation for CSF leak or pseudomeningocele. There were no cases of symptomatic nerve root herniation or new permanent neurological deficit. Radicular symptoms were stable or improved at the last follow-up.

CONCLUSION: Collagen-matrix cuff reconstruction is a simple, anatomically oriented option for circumferential lumbar root sleeve defects when primary closure is not feasible. In this initial single-center experience, the technique provided stable reconstruction without CSF-related complications and may represent a useful adjunct in selected complex root sleeve injuries.

PMID:42233683 | DOI:10.1227/ons.0000000000002083

Pediatr Surg Int. 2026 May 19;42(1):236. doi: 10.1007/s00383-026-06441-3.

ABSTRACT

PURPOSE: We aimed to investigate whether pledget presence, pledget composition, and full versus partial thickness suture technique affect the force esophageal tissue can withstand before tearing.

METHODS: A right thoracotomy was performed on 10 deceased fetal sheep, 110-114 days gestation. The esophagus was divided at the level of the carina and 2 cm of tissue was removed to mimic long-gap esophageal atresia. The pouches were sutured with horizontal mattress non-absorbable braided polyester suture using one of three methods: polytetrafluoroethylene (PTFE) pledgets, bovine pericardial pledgets, or no pledget, in full or partial thickness manner. Each suture was attached to a tensiometer and manually tightened at 50 gram-force / 30 s. Maximal force before esophageal tearing and time to tearing were measured. Results were compared using a linear mixed model.

RESULTS: PTFE pledgets withstood significantly more force than pericardial pledgets (p = 0.029) and provided longer duration before tearing compared to no pledget (p = 0.017) and pericardial pledgets (p = 0.047). Full versus partial-thickness technique made no difference.

CONCLUSION: In a deceased fetal lamb long-gap esophageal atresia model, PTFE pledgets improved tissue resistance to tearing (PTFE > pericardial) and prolonged stretch duration (PTFE > pericardial or no pledget). Suture thickness (full vs. partial) made no difference.

PMID:42154275 | DOI:10.1007/s00383-026-06441-3

Int J Biol Macromol. 2026 Jun;367:152551. doi: 10.1016/j.ijbiomac.2026.152551. Epub 2026 May 14.

ABSTRACT

The longevity and applicability of glutaraldehyde cross-linked commercial bioprosthetic heart valves (BHVs) that are the first choice for the transcatheter heart valve replacement (THVR) remain limited due to thrombus accumulation, calcification, inflammatory reactions and poor endothelialization. In this study, we first performed the prefunctionalization treatment of dual crosslinking by carboxymethylated λ-carrageenan and 4-pentenoic acid on decellularized bovine pericardium; subsequently, we conducted a post-functionalization treatment by dual modification of immobilizing the cyclodextrin (CD)/rutin and organic selenium onto above-mentioned doubly cross-linked (DC) bovine pericardium through the amidation reaction; finally, we obtained the anticipated bioprosthetic heart valve with multiple functions (DC + CD/Rutin+Se-BP). Uniaxial tensile tests demonstrated that this doubly cross-linked BHV exhibited superior mechanical properties compared with glutaraldehyde-treated bovine pericardium, which is expected to increase its structural stability and service life. By introducing the CD/Rutin complex and organic selenium, DC + CD/Rutin+Se-BP not only exhibited the ability to inhibit the adsorption of plasma proteins, platelet aggregation and thrombosis but also presented the excellent anti-inflammatory and anti-calcification characteristics both in vitro and in vivo. Furthermore, DC + CD/Rutin+Se-BP also exhibited stable in situ nitric oxide (NO) catalytic release ability due to the immobilization of organic selenium, which endowed bioprosthetic heart valve with excellent compatibility with human umbilical vein endothelial cells (HUVECs) and facilitated the long-term promotion of its endothelialization process. In summary, this approach combining dual cross-linking and dual modification provides a promising strategy for future design of BHVs, and DC + CD/Rutin+Se-BP exhibits a bright prospect in the clinical applications of BHVs.

PMID:42140293 | DOI:10.1016/j.ijbiomac.2026.152551