Papers by Serguei Melnitchouk
Annals of cardiothoracic surgery, 2013
Barlow's valve is a clinically important form of degenerative mitral valve (MV) disease that ... more Barlow's valve is a clinically important form of degenerative mitral valve (MV) disease that is characterized by unique clinical, echocardiographic and pathological features. Successful and durable repair of Barlow's MV represents a clinical challenge for most cardiac surgeons. An armamentarium of different MV repair techniques may be required, resectional, neochordal or plicational techniques. Although conventional sternotomy remains the mainstay approach for MV surgery in the majority of cardiac surgery centers, minimally invasive surgery (MIS) is becoming increasingly accepted amongst patients, referring physicians and practicing cardiac surgeons. As surgical approaches, instrumentation and operative experience develop, select centers are now performing MIS MV surgery for nearly all MV patients. Although successful Barlow's MV repair is more complex than that for most degenerative pathologies, several centers have published relatively large series of MIS MV repair for...
Seminars in cardiothoracic and vascular anesthesia, Jan 21, 2014
There is a growing demand from patients and referring physicians for minimally invasive cardiac s... more There is a growing demand from patients and referring physicians for minimally invasive cardiac surgery. Minimally invasive cardiac procedures are technically unique from conventional cardiac procedures and require a thorough understanding of the surgical, anesthetic, and perfusion strategies. Strategies include routine use of augmented venous drainage, alternative arterial and venous cannulation sites, and special cannulas designed for minimally invasive procedures. The following review describes the strategies and safety systems that should be considered when performing minimally invasive cardiac surgery.
European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery, 2004
To report mid-term results of stent-graft (SG) implantation in acute thoracic aortic rupture as a... more To report mid-term results of stent-graft (SG) implantation in acute thoracic aortic rupture as alternative to conventional open surgery with its associated high morbidity and mortality rates. Out of a series of 69 patients undergoing thoracic aortic SG implantation since 1998, 24 (mean age 57+/-19 years, range 20-85-years-old) patients were treated on an emergency basis for hemorrhage control. The indication for SG placement was acute traumatic aortic rupture in 15 patients, type B dissection with contained rupture in 3 patients, penetrating aortic ulcer with periaortic hematoma in 3 patients, and thoracic aortic aneurysm rupture in 3 patients. Preoperative assessment was done by computed tomography (CT) scanning and echography. Patients were treated in the angiography suite by implantation of Excluder (n = 18) Talent (n = 4) Corvita (n = 1) and Vanguard (n = 1) self-expanding grafts. Local anesthesia was the most frequently used anaesthesiologic technique. Technical success rate o...
Journal of the American College of Cardiology, 2014
European Journal of Cardio-Thoracic Surgery, 2002
Objective: Vascular-derived cells represent an established cell source for tissue engineering of ... more Objective: Vascular-derived cells represent an established cell source for tissue engineering of cardiovascular constructs. Previously, cell isolation was performed by harvesting of vascular structures prior to scaffold seeding. Marrow stromal cells (MSC) demonstrate the ability to differentiate into multiple mesenchymal cell lineages and would offer an alternative cell source for tissue engineering involving a less invasive harvesting technique. We studied the feasibility of using MSC as an alternative cell source for cardiovascular tissue engineering. Methods: Human MSC were isolated from bone marrow and expanded in culture. Subsequently MSC were seeded on bioabsorbable polymers and grown in vitro. Cultivated cells and seeded polymers were studied for cell characterization and tissue formation including extracellular matrix production. Applied methods comprised flow cytometry, histology, immunohistochemistry, transmission (TEM) and scanning electron microscopy (SEM), and biochemical assays. Results: Isolated MSC demonstrated fibroblast-like morphology. Phenotype analysis revealed positive signals for alpha-smooth muscle actin and vimentin. Histology and SEM of seeded polymers showed layered tissue formation. TEM demonstrated formation of extracellular matrix with deposition of collagen fibrils. Matrix protein analysis showed production of collagen I and III. In comparison to vascular-derived cell constructs quantitative analysis demonstrated comparable amounts of extracellular matrix proteins in the tissue engineered constructs. Conclusions: Isolated MSC demonstrated myofibroblast-like characteristics. Tissue formation on bioabsorbable scaffolds was feasible with extracellular matrix production comparable to vascular-cell derived tissue engineered constructs. It appears that MSC represent a promising cell source for cardiovascular tissue engineering. q
ASAIO Journal, 2002
In cardiovascular tissue engineering, synthetic or biologic scaffolds serve as templates for tiss... more In cardiovascular tissue engineering, synthetic or biologic scaffolds serve as templates for tissue development. Currently used scaffolds showing toxic degradation and immunogenic reactions are still far from ideal. We present a new alternative method to develop completely autologous human tissue without using any scaffold materials. Human vascular cells of arterial and venous origin were cultured to form cell sheets over a 4 week period under standard conditions. Thereafter, cell sheets of each origin were folded and cultured in a newly developed frame device for an additional 4 weeks. Controls remained under standard culture conditions. Tissue development was evaluated by morphology and biochemical assays. The formation of multilayered cell sheets and production of extracellular matrix were observed in all groups. Folded and framed neo-tissue showed a solid structure, with increased matrix formation and tissue organization when compared with the control groups. DNA content indicated significantly lower cell proliferation, and hydroxyproline assay indicated significantly higher collagen content in the framed cell sheets. We present a new approach to the engineering of cardiovascular tissue without the use of biodegradable scaffold material. Three-dimensional, completely autologous human tissue may be developed on the basis of this structure, thus avoiding scaffold induced toxic degradation or inflammatory reaction.
The Annals of Thoracic Surgery, 2002
Background. Tissue engineering of viable, autologous cardiovascular constructs with the potential... more Background. Tissue engineering of viable, autologous cardiovascular constructs with the potential to grow, repair, and remodel represents a promising new concept for cardiac surgery, especially for pediatric patients. Currently, vascular myofibroblast cells (VC) represent an established cell source for cardiovascular tissue engineering. Cell isolation requires the invasive harvesting of venous or arterial vessel segments before scaffold seeding, a technique that may not be preferable, particularly in pediatric patients. In this study, we investigated the feasibility of using umbilical cord cells (UCC) as an alternative autologous cell source for cardiovascular tissue engineering.
Circulation, 2002
We previously demonstrated the successful tissue engineering and implantation of functioning auto... more We previously demonstrated the successful tissue engineering and implantation of functioning autologous heart valves based on vascular-derived cells. Human marrow stromal cells (MSC) exhibit the potential to differentiate into multiple cell-lineages and can be easily obtained clinically. The feasibility of creating tissue engineered heart valves (TEHV) from MSC as an alternative cell source, and the impact of a biomimetic in vitro environment on tissue differentiation was investigated. Human MSC were isolated, expanded in culture, and characterized by flow-cytometry and immunohistochemistry. Trileaflet heart valves fabricated from rapidly bioabsorbable polymers were seeded with MSC and grown in vitro in a pulsatile-flow-bioreactor. Morphological characterization included histology and electron microscopy (EM). Extracellular matrix (ECM)-formation was analyzed by immunohistochemistry, ECM protein content (collagen, glycosaminoglycan) and cell proliferation (DNA) were biochemically quantified. Biomechanical evaluation was performed using Instron(TM). In all valves synchronous opening and closing was observed in the bioreactor. Flow-cytometry of MSC pre-seeding was positive for ASMA, vimentin, negative for CD 31, LDL, CD 14. Histology of the TEHV-leaflets demonstrated viable tissue and ECM formation. EM demonstrated cell elements typical of viable, secretionally active myofibroblasts (actin/myosin filaments, collagen fibrils, elastin) and confluent, homogenous tissue surfaces. Collagen types I, III, ASMA, and vimentin were detected in the TEHV-leaflets. Mechanical properties of the TEHV-leaflets were comparable to native tissue. Generation of functional TEHV from human MSC was feasible utilizing a biomimetic in vitro environment. The neo-tissue showed morphological features and mechanical properties of human native-heart-valve tissue. The human MSC demonstrated characteristics of myofibroblast differentiation.
The Journal of Thoracic and Cardiovascular Surgery, 2014
Objective: Barlow's disease remains a challenging surgical pathology in patients presenting with ... more Objective: Barlow's disease remains a challenging surgical pathology in patients presenting with mitral regurgitation. We reviewed our early and long-term results for patients with Barlow's disease who underwent minimally invasive mitral valve surgery.
Uploads
Papers by Serguei Melnitchouk