Caused Heart Affliction : Valvular

Courtney M. Townsend JR., Md , in Sabiston Textbook of Surgery , 2022

Mitral Valve Replacement and Repair

The mitral valve is typically exposed through a left atriotomy, made inductive to the pulmonary veins (Fig. 61.16). A right atriotomy and incision through the atrial septum also provides excellent exposure to the mitral valve. Even greater exposure tin exist provided by a "superior septal" approach joining the right atrial and septostomy incisions onto the dome of the left atrium, but this approach requires more than extensive closure.

Mitral Valve Replacement

Minimal valve leaflet resection (typically of a portion of the anterior leaflet) is currently preferred for mitral valve replacement, making best efforts to preserve the chordae and subvalvular apparatus in continuity with the valve annulus. If the chordae or leaflets are severely calcified or fibrotic, resection may be required to facilitate implantation of an fairly sided valve prosthesis without perivalvular leak. Afterward the resected valve orifice is sized (using a plastic avatar), the selected valve prosthesis is typically secured to the valve annulus using circumferentially-placed, nonabsorbable, braided pledgeted horizontal mattress sutures (Fig. 61.16B). The sutures are tied securely then at that place is no perivalvular defect, which would allow a regurgitant leak, and the atriotomy is closed afterward de-ambulation of the heart (Fig. 61.16C).

Mitral Valve Repair

A wide variety of surgical techniques may be employed to repair primary MR lesions. Almost normally, flail or prolapsing segments of the valve can exist excised via limited triangular or more than extensive quadrangular resections, and leaflet continuity restored by suturing the resected leaflet edges back together (Fig 61.17A). Relaxing incisions along the posterior leaflet base facilitate a sliding annuloplasty, which may exist used to reduce tension on the repair and to subtract the height of the posterior leaflet. This helps prevent postresection MR resulting from systolic anterior motion (SAM) of the anterior mitral leaflet, which may become displaced towards the aortic outflow tract after inadequate resections.

Another choice for mitral repair is the creation of neochordae, which can be created or preselected using Gore-Tex suture and should be sized to the meridian of the annulus. The neochordae are attached to the papillary muscle and the free edge of the leaflet to provide appropriate leaflet support and prevent leaflet prolapse.

A ring annuloplasty should be performed with all mitral valve leaflet repairs as this maneuver has been shown to significantly improve the immovability of repair and tin be used as a stand-lonely process to address MR arising from a dilated annulus (Fig. 61.17B). Insertion of an annuloplasty band helps restore normal annular geometry and ensure an advisable coaptation zone of 6 to 8 mm between anterior and posterior leaflets. Numerous device options are available for annuloplasty, including rigid or flexible and partial or complete rings, and particularly configured "3D" rings accept also been developed to correct the apical and lateral displacement of the posterior valve leaflet associated with functional MR, as have subvalvular procedures seeking to realign the papillary muscles. 25 Data is indefinite on which of these ring types provides the best outcomes.

Intraoperative Echocardiography

Ronald A. Kahn Physician , ... Joseph S. Savino MD , in Essentials of Cardiac Anesthesia, 2008

Category I

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Heart valve repair

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Built heart surgery

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Hypertrophic obstructive cardiomyopathy

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Endocarditis

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Acute aortic dissection

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Acute, unstable aortic aneurysm

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Aortic valve function in the setting of aortic autopsy

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Traumatic thoracic aortic disruption

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Pericardial tamponade

Category 2

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Myocardial ischemia and coronary artery affliction

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Increased hazard of hemodynamic disturbances

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Centre valve replacement

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Aneurysms of the heart

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Intracardiac masses

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Intracardiac strange bodies

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Air emboli

•

Intracardiac thrombi

•

Massive pulmonary emboli

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Traumatic cardiac injury

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Chronic aortic dissection

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Chronic aortic aneurysm

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Detection of aortic atheromatous affliction every bit a source of emboli

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Evaluating the effectiveness of pericardiectomies

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Middle-lung transplantation

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Mechanical circulatory support

Category III

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Other cardiomyopathy

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Emboli during orthopedic procedures

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Simple pericarditis

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Pleuropulmonary disease

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Placement of intra-aortic airship pump, pulmonary avenue catheter

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Monitoring the administration of cardioplegia

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CARDIAC PROSTHESES

Jack W. Love , in Principles of Tissue Engineering (2nd Edition), 2000

SPECULATION About THE FUTURE

With regard to the use of tissue for heart valve repair or replacement, it is necessary to consider which tissue to use. The source of the tissue is 1 event, and the specific tissue is another issue. The sources in 1999 are domestic animals (cattle and pigs), human cadavers, and autologous tissue taken from the host. The specific tissues bachelor in 1999 are either natural valves or pericardium used to make valves. The natural valves used commercially are either porcine aortic valves, fully tanned with glutaraldehyde and stent mounted, or untanned human cadaver valves for aortic replacement, with or without accompanying aortic root replacement. Bovine pericardium, fully tanned with glutaraldehyde, is used for replacement when fashioned into stent-mounted or stentless bioprostheses, or for repair purposes. Autologous pericardium treated with a brief immersion in glutaraldehyde is being used for repair of mitral valves past Carpentier, for repair of aortic valves by Duran, and for mitral replacements by Deac. The Autogenics stented autologous tissue bioprosthesis has been used for aortic and mitral replacement. It is not all the same clear which tissue, from which source, will prove to exist the tissue of choice. Nor is it clear how the tissue will be best used, either for repair techniques or for replacement techniques, with or without a stent.

In discussing the apply of tissue for repair or replacement of diseased heart valves, it is germane to consider illness manual with animal or cadaveric tissue. The risk is extremely small, but definite and proved. With fauna tissue, there is concern for the manual of what have come to be known equally the prion diseases. Bovine spongioform encephalopathy, or BSE, is the manifestation of prion disease in cattle. In sheep, it is known every bit scrapie. In that location is no known equivalent in domestic pigs, and thus the porcine heterograft is non known to carry the risk of prion manual. The prion diseases, although fortunately rare, are formidable afflictions. In that location is no in vivo exam for the diseases, there is no known treatment, and the diseases are uniformly fatal. Prion illness has been epidemic among domestic sheep and cattle in Europe, merely it is non clear if the diseases take appeared in Due north American animals. Transmission from animals to human being has been documented from the apply of animal tissue products. The all-encompassing review by Prusiner (1995), who coined the term "prion," should be consulted for details.

With cadaveric tissue, the rare only definite risk is transmission of the human immunodeficiency virus (HIV), leading to AIDS. Donors tin be tested for HIV, simply the problem is the window of unknown length that can exist between infection and development of a positive test for the virus. One example has been documented of a donor who tested negative for the virus, whose organs transmitted the virus to multiple recipients of his heart, liver, kidneys, and os (Simonds et al., 1992). Autonomously from the problem of the window between infection and test positivity, another aspect of the risk of HIV transmission is the imperfect sensitivity and specificity of the examination for HIV antibodies. Until a more reliable, early test for HIV is adult, or until at that place is an constructive treatment for AIDS, the use of cadaveric tissue will carry hazard of transmission of the illness.

Autologous tissue carries no hazard of illness manual, and that fact must be recognized as a strong statement for its use whenever possible. From the standpoint of disease transmission alone, it may be speculated that autologous tissue will be more than widely used for both repair and replacement of diseased heart valves in the future. Patients will always need that risks of all kinds associated with surgical treatments exist minimized. In the very litigious environs that exists in the United states of america, hazard minimization is a major consideration for physicians.

Autologous tissue can be used for repair or replacement, and autologous tissue replacement valves tin can be either stent mounted or unstented. The use of autologous tissue for both repair and replacement of diseased centre valves is an old thought, unsuccessful when first tried with fresh, untreated tissue, and now successful with tissue that has been treated with a brief immersion in glutaraldehyde. To appointment, the only autologous tissue that has been used successfully is pericardium. Pericardium, both fully tanned bovine and lightly tanned autologous, now has a proved record of successful employ for valve repair and replacement. Patients having 2nd or third cardiac operations may not accept suitable pericardium bachelor, and information technology thus becomes important to consider other candidate tissues. Farther, materials scientists are concerned about isotropy and anisotropy in tissues used for valve repair or replacement. Valvular leaflets are anisotropic, whereas pericardium is isotropic (Zioupos et al., 1994). Fascia lata, used by Senning, should be reevaluated as a candidate tissue. Venous tissue, peritoneum, and rectus fascia take all been used or suggested for use in the by every bit fresh, untreated tissue (Love, 1993). These tissues should besides be reexamined for use afterward light tanning with glutaraldehyde. A tissue other than pericardium could prove to be best for valvular applications.

Another topic of speculation virtually the future is the potential for development of techniques for repairing or replacing heart valves nonsurgically. The potential is for techniques that would enable the treating medico, surgeon or cardiologist, to introduce a folded valve by fashion of a catheter into the eye or great vessels, there to unfold and attach the valve in the orthotopic position past fixation ways yet to be developed. With constantly improving catheter technology and imaging techniques, it is not beyond the realm of near possibility that nonsurgical handling of valvular heart affliction may become viable. Information technology is obvious that only a tissue valve could be used in this way; mechanical valves cannot be compressed in size and thus could not be used this way.

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Drug‐Induced and Iatrogenic Neurological Disorders

Katie Kompoliti , Stacy S. Horn , in Textbook of Clinical Neurology (Third Edition), 2007

Cardiac Transplantation

Neurological complications recognized in the commencement weeks afterward cardiac transplantation are similar to those seen afterward routine CABG surgery or heart valve repair ( Table 55‐12). They include cerebrovascular disease, anoxic‐ischemic encephalopathy, seizures, and peripheral nerve disorders. 197 Vascular headaches accompanied by nausea and vomiting may occur the first week afterwards transplantation and are felt to be associated with a rapid shift from low preoperative to high postoperative hateful arterial pressures. Psychotic behavior with hallucinations, delusional thought process, and disorganized behavior can occur during the first ii weeks after transplantation or as a belatedly complication (Video 22, Delusional Thinking). When it occurs in the first 48 hours and is accompanied by disorientation and impaired memory, it probably represents a behavioral response to intraoperative cognitive ischemia‐hypoxia. If it begins 2 to 5 days afterward surgery, retention is preserved, and there is rapid resolution with environmental reorientation, then a multifactorial ICU psychosis may be present. If psychotic behavior presents two to four weeks following transplantation, and then a full evaluation for an opportunistic infection is indicated. 197

Immunosuppression remains the major crusade of late neurological complications after cardiac transplantation. Opportunistic infections tin occur as early every bit 2 weeks afterwards surgery and immunosuppression, but commonly there is an interval of at least a calendar month. Focal meningoencephalitis or brain abscess, meningitis, and encephalitis are three common presentations of infections in cardiac transplant recipients. Aspergillus, Toxoplasma gondii, Cryptococcus, Listeria, Candida, and Nocardia are the near frequent nonviral organisms. The most frequent viral infections are caused past the herpesviruses, with cytomegalovirus being the about common. 188,197 Aseptic meningitis has been reported in five% of patients receiving OKT3 and presents as mental condition and behavioral changes. 188

The use of cyclosporine since the early on 1980s has allowed significant lowering of corticosteroid requirements and has reduced the frequency of its side effects. In that location accept been a number of neurological effects ascribed to cyclosporine, however, including tremor, lowered seizure threshold, confusion, musculus weakness, ataxia (Video seven, Abnormal Tandem Gait), paresthesias, visual hallucinations, and a leukoencephalopathy with cortical blindness. 188,197 These neurotoxic side furnishings chop-chop remit with reduction of the dose of cyclosporine. When seizures occur and anticonvulsants are indicated, selection of the best amanuensis may be hard because phenytoin, phenobarbital, and carbamazepine can decrease the blood levels of cyclosporine. Finally, immunosuppression predisposes the patient to the evolution of primary or secondary lymphoma of the encephalon.

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Aortic Valve-Sparing Operations

Tirone E. David , in Atlas of Cardiac Surgical Techniques (Second Edition), 2022

Step five Pearls and Pitfalls

◆

Aortic valve-sparing operations are complex procedures. A sound noesis of the functional anatomy and pathology of the aortic root and technical expertise are needed for their performance. Equally with any other blazon of heart valve repair, it should non exist performed if the aortic cusps are grossly abnormal. From the preoperative selection of patients by TEE to the intraoperative analysis of the aortic cusps and root and what is needed to restore the functional beefcake of the aortic valve, every step is crucial.

◆

Sizing of the graft is difficult for the surgeon who is learning to perform these operations. Sizing of the graft is easier for remodeling of the aortic root than for reimplantation of the aortic valve. The guidelines for sizing the graft for reimplantation of the aortic valve given in this chapter are based more on clinical feel than on scientific investigation of functional anatomy. The length of the FMs of the cusps, degree of scalloping of the AA, and bore of the STJ can all be altered during reconstruction of the root, but the height of the cusps cannot. For this reason, I use the average elevation of the cusps to guess the advisable diameter of the AA at the level of its nadir. By using grafts with a bore equal to twice the boilerplate height of the cusps, the radius of the reconstructed AA becomes equal to the acme minus the thickness of the aortoventricular junction because it is sutured within the graft. This reduction in diameter of the annulus has proven constructive in allowing the cusps to coapt well above the nadir of the annulus, and it provides a good seal of the aortic orifice during diastole.

◆

The level of coaptation of the aortic cusps has been shown to be important for the durability of these procedures. If the cusps coapt at the same level as the annulus, the probability of prolapse of a cusp with consequent aortic insufficiency is profoundly increased, compared with cusps that coapt at least 8 mm above the nadir of the AA. Thus, sizing of the graft and shortening the length of the cusps' FMs are extremely important determinants of belatedly valve function.

◆

As illustrated in Fig. 13.3, the AA evolves along single horizontal planes. The just geometric shape suitable to stabilize a dilated AA is a cylinder. Thus, a straight tubular Dacron graft is probably the best shape for reimplantation of the aortic valve. Newer grafts with neoaortic sinuses are spherical and probably deform the AA once the valve is secured within them. Thus, I exercise non recommend these grafts for reimplantation.

◆

Aortic valve-sparing operations are extensive, and hemostatic anastomoses between the various components are of utmost importance. Coagulopathy at the stop of a long cardiopulmonary bypass is common, and every measure must be taken to avoid mechanical bleeding.

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Polyacetals

Sheiliza Carmali , Steve Brocchini , in Natural and Synthetic Biomedical Polymers, 2022

13.2.5 Polyacetals in Tissue Technology

While much recent piece of work has been described to develop polyacetals for drug delivery applications, and historically they have been used as implant materials, more recently, they accept been examined as potential scaffold materials in tissue engineering. Implants of Delrin (polyoxymethylene) to repair middle valves were examined, but there was too much swelling in vivo [127]. However, this polyacetal has been used as an orthopedic implant [128] and as an orthopedic implant-coating material [129,130] to interface with bone tissue as this polyacetal has a similar modulus to bone. Ultrasound is used in the diagnosis of osteoporosis and porous polyacetal blocks were establish useful to proceeds insights into bone porosity and ultrasonic properties [131].

Cross-linked cyclic polyacetals accept been examined in recent years for use in regenerative medicine [125] in an effort to minimize the inflammatory response often caused past deposition side products (east.one thousand., acids from polyesters). One case is the copolymer hydrogel poly[poly(ethylene glycol)-co-cyclic-acetal] 42 (Figure 13.8). The diol 39 is prepared from trimethanol propane and iii-hydroxy-2,2-dimethylpropanal [132]. The prepolymer 40 was isolated at weight-average molecular weights ranging from 5000 to 44,000   g/mol and was then bis-acrylated to give 41 . Redox initiators were used to cantankerous-link 41 to give the hydrogel 42 . As with other polyacetals, these h2o-swellable polyacetal hydrogels 42 underwent acrid-dependent deposition.

Figure 13.8. Monomer 39 is used to prepare circadian polyacetal hydrogels such as 42 for potential use in tissue regeneration applications [125,132].

Other cross-linked polyacetals based on diol 39 have besides been described [125]. The corresponding diacrylate 31 , which is derived from diol 39 , was prepared and then direct exposed to redox initiators to form the corresponding cross-linked polyacetal. The diacrylate 31 tin can also be mixed in different proportions with a PEG-diacrylate (PEGDA) to class analogous hydrogel networks. These networks are related to that shown for hydrogel 42 and together accept immune a wide range of materials of like composition to be evaluated. These cyclic-acetal hydrogels are being evaluated for potential craniofacial tissue engineering applications [133]. Composites of these cyclic polyacetals and uniformly distributed hydroxyapatite particles have been shown to facilitate osteogenic differentiation of encapsulated os marrow stromal cells by potentially promoting osteogenic signal expression. Information technology is also idea that lack of acidic by-products from acetal degradation of these osteogenic materials contributes to their biocompatibility [133,134]. The diol 39 has also been allylated to be used with four-arm thiols in the presence of initiators to undergo a thiol-ene reaction to give hydrogel networks for written report in tissue engineering [135].

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Research in Cardiac Surgery

Robert Thousand. MentzerJr., ... Robert D. Lasley , in Surgical Inquiry, 2001

VI. Conclusion

Although research in cardiac surgery has changed dramatically over the past 50 years, the problems facing cardiac surgeons today are but as challenging as those solved by clinician-scientists in the past. This is due to the increasing need to develop and implement therapies to treat the complications that occur after open-heart surgery. The aim is to not only amend survival, simply likewise to enhance the overall quality of life after heart surgery. Research in cardiac surgery, all the same, is and must go on to exist grounded in inquiry at the basic science level. Although cardiac transplantation, replacement of heart valves, performance of complex congenital center illness operations, and coronary artery bypass grafting represent spectacular accomplishments, fundamentally all these corrective procedures withal involve exposing the heart or a region of the center to a period of ischemia. As a consequence, few, if any, cardiac operations are completely free of pregnant complications. Heart transplantation is a good instance of a procedure in which postischemic myocardial dysfunction plays an important role in outcome. The 30-day mortality subsequently cardiac replacement currently ranges between 5 and 15% and is most often related to primary graft dysfunction secondary to prolonged ischemic times and/or inadequate myocardial preservation. Allograft rejection, donor eye ischemia, progressive myocyte loss over time, and the evolution of graft vasculopathy besides have been associated with prolonged ischemic times. Regardless of the cause, the need to better both the short- and long-term survival is urgent, peculiarly considering the 1- and 5-year survival rates afterwards cardiac transplantation still remain at 80 and 60%, respectively. Likewise, although cardiac surgeons can successfully replace heart valves, repair complex built heart defects, and revascularize the severely ischemic heart, these operations do non necessarily prevent patients from experiencing myocyte loss over time, which ultimately tin progress to centre failure. Thus, it is non surprising that myocardial stunning, myocardial hibernation, ischemic preconditioning, and apoptosis are currently areas of major investigation in cardiac surgery today.

More investigation is needed into myocardial stunning and hibernation in order to encompass fully the events that take identify during both ischemia and reperfusion. Furthermore, enquiry is needed to elucidate how the purported primary mediators, intracellular calcium overload, and oxidative stress caused by ROS generated at the onset of reperfusion upshot in reversible and irreversible myocardial injury. More specifically, experiments demand to exist designed to determine how derangements in the various proposed targets of ROS, such as the sarcolemma, the sarcoplasmic reticulum, the mitochondria, and the extracellular collagen matrix, actually result in stunning and hibernation. Likewise, studies are needed to address the function ischemia/reperfusion plays in modulating intracellular acidosis and activation of the sodium/hydrogen exchanger. If the latter is responsible for increased transsarcolemmal calcium influx and intracellular overload, is the evidence strong plenty to warrant the employ of Na+/H+ exchange inhibitors to preclude or reduce the incidence of myocardial infarction or death later open-heart operations? What are the roles, if any, of gene regulation and receptor expression in stunning and hibernation? What are the reparative processes that take identify during the recovery process and why does recovery time vary according to the duration and degree of ischemia? When does reversible injury become programmed irreversible injury? Does apoptosis correspond only one attribute of a continuum of ischemia, and, if and then, is programmed cell death reversible, and at what point in time?

Similarly, there are numerous other questions that demand to be answered with respect to both classic and delayed preconditioning. Future research must focus on the triggers, mediators, intracellular signaling pathways, and effectors that actually attune this powerful endogenous form of myocardial protection. Findings from these types of studies could atomic number 82 to the development of new pharmacologic preconditioning agents that could be used during cardiac surgery to enhance the heart's tolerance to ischemia and reduce the incidence of stunning, infarction, and centre failure. Currently, several endogenous and exogenous agents are under investigation as potential cardioprotective agents. These include preconditioning mimetics such equally adenosine A1 and A3 receptor agonists, ATP-dependent potassium channel openers, bradykinin, and nitric oxide donors. Ultimately, elucidation of the mechanisms underlying the potent endogenous cardioprotective furnishings of IPC and hibernation and the deleterious consequences of stunning and apoptosis depends on focused basic science inquiry that is innovative, hypothesis driven, utilizes modern investigative technology, and is translational in nature.

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Cardiac Valve Replacement and Related Interventions

F.J. Schoen , J. Butany , in Cardiovascular Pathology (Quaternary Edition), 2022

Valve Repair and Valve Sparing Procedures

Reconstructive procedures for mitral insufficiency of various etiologies and to minimize the severity of rheumatic mitral stenosis are at present highly constructive and commonplace [250,251]. AV repair, on the other hand, is more complex and not as widely used [252]. Reconstructive therapy of selected patients with AI and aortic dilation may exist undertaken in some cases, though pure repair of AS is notably more than challenging (come across subsequently). In general, the major advantages of repair over replacement chronicle to the elimination of prosthesis-related complications and the demand for chronic anticoagulation therapy. Other reported advantages include a lower hospital mortality, meliorate long-term function owing to the ability to maintain the continuity of the mitral appliance, and a lower rate of postoperative infective endocarditis.

In the last 15-20 years, the techniques of centre valve repair procedures accept been evolving. In developed countries, much of MV disease is degenerative and related to myxomatous (floppy and incompetent) valves, while in other parts of the world, rheumatic valvular illness is yet the common crusade of MV-associated disease. In the younger patient with degenerative MV disease with few comorbidities, the results of MV repair are very adept.

Both the aortic and MVs are circuitous structures and should be considered in the context of the surrounding and related tissues (i.e., apparatus) and the physiologic integration of all parts. A proficient understanding of the valve structure and function is essential for interpreting the changes produced by the repair/reconstruction procedures. In the example of the MV, normal function depends on the continuity and coordinated movement of the leaflets, the annulus, the atrial tissue above, and the ventricular myocardium below, the chordae tendineae, and the papillary muscles. Dysfunction of any of the components tin can atomic number 82 to valvular dysfunction. The AV similarly is a complex structure, whose proper function depends on intact AV cusps, aortic annulus, aortic sinuses, A-Five junction, and sinotubular junction.

MV "repair" with open commissurotomies was offset performed in the 1940s every bit an approach to rheumatic mitral stenosis. Today, rheumatic mitral disease can and is yet treated with commissural incision, removal of calcified tissue, and replacement of damaged or significantly shortened chordae tendineae. Commissurotomy may exist employed in the operative repair of some stenotic MVs in which fibrosis and shortening of both cords and leaflets have markedly decreased leaflet mobility and area. If the anterior mitral leaflet is significantly anatomically or functionally shortened, the surgeon tin can increase its length by placing a patch of native or glutaraldehyde-fixed bovine pericardium. Factors that compromise the late functional results of or prevent mitral commissurotomy and thereby necessitate valve replacement include: (i) left ventricular dysfunction; (2) pulmonary venous hypertension and right-sided cardiac factors, including correct ventricular failure, tricuspid regurgitation, or their combination; (3) systemic embolization; (4) coexistent cardiac disorders, such equally coronary avenue, or AV diseases; (5) residual or progressive MV illness, including valve restenosis, residuum (unrelieved) stenosis, or regurgitation induced at operation; (vi) advanced leaflet (especially commissural) calcification; (seven) subvalvar (predominantly chordal) fibrotic changes; and (viii) significant regurgitation owing to retraction. Percutaneous balloon mitral valvuloplasty has been used to care for mitral stenosis for over two decades, with excellent success in patients with suitable valvular and subvalvular morphology [253]. Withal, because airship valvuloplasty largely involves separation of the fused leaflets at the commissures, this procedure is as well unlikely to provide significant benefit to patients with the valve features summarized above.

Structural defects responsible for chronic mitral regurgitation include: (1) dilation of the mitral annulus; (2) myxomatous modify and leaflet prolapse into the left atrium, with or without elongation or rupture of chordae tendineae; (3) redundancy and deformity of leaflets; (4) leaflet perforations or defects; and (5) restricted leaflet motility as a result of commissural fusion in an opened position, and leaflet retraction, or chordal shortening or thickening. MV repair for regurgitation was pioneered by Dr. Alain Carpentier [254]. Every bit much as lxx-90% or more of degenerative MV incompetence is believed amendable to successful repair. The mid- and long-term results are very expert with no more than than about ten% of patients needing a reoperation. Techniques for MV repair involve removal and/or repositioning of leaflet tissue, resuspension of the leaflets, if necessary and, if the annulus is dilated, a reduction in the annulus size with an annuloplasty ring or other device [255,256]. Materials used for the repairs include fresh pericardium, glutaraldehyde fixed bovine pericardium, and constructed (PTFE) sutures [257]. In patients who accept small perforations of leaflet tissue (aortic or mitral) or where there is an isolated patch of infective endocarditis with vegetation on it, a surgeon may excise this area and "make full" the gap with a patch of native pericardium or glutaraldehyde fixed bovine pericardium. This patch will bear witness the same changes equally pericardial patches show at other sites, that is, the degradation of tissue on both of its surfaces. The surgeon volition usually identify a redundant patch because the tissue tends to shrink after implantation. Figure 13.twenty illustrates the pathologic anatomy of diverse open and catheter-based MV reconstruction procedures [259–260].

Effigy 13.twenty. Reconstructive procedures for mitral valve disease. (a) Open up surgical commissurotomy in mitral stenosis; incised commissures are indicated by arrows. (b) Balloon valvuloplasty for mitral stenosis. Commissural fractures and splits are indicated by tapes. (c) Mitral valve repair with annuloplasty ring. (d) Dehisced mitral annuloplasty ring (arrow). (e) ePTFE suture replacement (arrow) of ruptured cord in myxomatous mitral valve early on post-obit surgery. (f) Constructed "chordae tendineae" at over 2 years mail implantation show that nearly the entire length of the chords is covered with a gray-white layer of tissue (white arrow) and thrombotic vegetations (reddish arrow).

 (a) Reproduced past permission from Ref. [7]. Copyright WB Saunders, 1987. (b), (c), and (e) From Ref. [258]; (d) Courtesy of William A. Muller, M.D., Ph.D., Northwestern University Schoolhouse of Medicine, Chicago, IL, United states of america.

Mitral repair techniques used include: (1) reduction in the height of the elongated chordae tendineae done past an incision in the tip of the papillary muscle, reimplantation of the redundant chordal tissue into this, and suturing the split papillary muscle together; (2) artificial chordae tendineae fashioned out of PTFE and extending from the leaflet tissue to the tip of the papillary muscle in a figure of eight manner; (3) transfer of some chordae from 1 papillary muscle to the other or one leaflet to the other (i.e., chordal transfer); or (4) border-to-border repair, a procedure performed to reduce the size of the MV orifice and first devised past Alfieri [261]. In this technique, the anterior and posterior leaflets are approximated and stitched together by two or more sutures and the MV then ends up with two orifices. Pre- and intraoperative imaging is crucial for successful valve repair.

In a repair process that may take been abased on transesophageal echocardiography (TEE) sit-in of persistent incompetence, the resection/repair and bogus chordae will be easily axiomatic (see Effigy 13.20e). The earliest change is the deposition of a minor amount of fibrin platelet thrombus, on the surface of this PTFE and progressively, the generation of new tissue, starting form the two ends. Artificial chordae fashioned from PTFE may in fourth dimension look exactly like native chordae, although they may exist thicker, especially if adherent to adjacent native chordae or if fibrosis has occurred (see Figure 13.20f). Artificial chordae made of ePTFE rarely too have calcification, both in the interstices of the synthetic cloth and on the new tissue deposited on the surface. Very rarely, a calcified artificial chord may fracture.

Most of these procedures also accept an annuloplasty process performed to reduce the size of the annulus. Should reoperation be necessary, the surgeon would excise the annuloplasty band. Depending on its type (soft or hard), the annuloplasty ring will prove pannus on the textile covering its surface and in the softer rings testify tissue ingrowth into the interstices of the synthetic cloth and, to a bottom degree, on and into the fabric roofing the hard annuloplasty band. Occasionally, pannus growth onto the annuloplasty ring and the adjacent portion of the leaflet tissue tin can lead to stenosis of the orifice and failure.

Today, an interventional approach is successfully used to appose the cardinal portions of the two leaflets through a "Mitral clip®" (or Eastward-valve), which holds the ends of the two leaflets together, thereby creating the double outlet valve. A surgically excised Alfieri sew together or an edge-to-edge repair using the endovascular MitraClip® shows the deposition of gristly tissue on the surface and resultant thickening of the tissues at this point (Figure xiii.21) [262].

Figure 13.21. Border-to-edge approximation of the anterior and posterior leaflets of the mitral valve is achieved past deployment of clip (Evalve™ mitral clip device) that is analogous to an Alfieri stitch, thereby creating a double orifice with improved leaflet coaptation.

 Reproduced by permission from Ref. [174], p. 241-56.

In contrast to the favorable short- and long-term outcomes of MV repair in general, reconstructive AV surgery has been of limited usefulness. Figure thirteen.22 illustrates representative difficulties. AV repair for stenosis is less ordinarily used since AV disease is unremarkably associated with significant calcification. In balloon dilation of calcific AS, improvement derives from commissural separation, fracture of calcific deposits, and stretching of the valve cusps (see Figure 13.22a). Nevertheless, individual functional responses vary considerably and data advise a modest early incremental benefit, high early mortality, a loftier restenosis rate, and piffling lasting do good [264]. The major complications include cerebrovascular accident secondary to embolism, massive regurgitation owing to valve trauma, and cardiac perforation with tamponade. Fractured calcific nodules can themselves prove dangerous [265]. In pediatric cases in which the cusps are more often than not pliable, cuspal stretching, vehement, or avulsion may also occur. Attempts take been fabricated to "debride" nodular calcific masses. Decalcification of calcific AV tissue is difficult and since many of the calcific nodules extend through the thickness of the cusp, the possibility of perforating the cusp is always present (encounter Figure 13.22b and c). Moreover, calcification tends to recur in these valves. A congenitally aberrant, just incompetent, AV (without calcification) is more likely to exist amenable to repair. "Plication" of the redundant complimentary margin, or the commissural cease(s) to refashion an oversized orifice that is more appropriate in size, may yield a satisfactory functional result (see Figure thirteen.22d).

Figure 13.22. Reconstructive procedures for aortic valve illness. (a) Aortic valve balloon valvuloplasty for degenerative calcific aortic stenosis, demonstrating fractures of nodular deposits of calcifications highlighted by tapes. (b) and (c) Operative decalcification of the aortic valve. (b) Aortic valve after operative mechanical decalcification demonstrating perforated cusp. (c) Depression-power photomicrograph of cross-section of aortic valve cusp after decalcification with lithotripter. Dashed line indicates guess extent of original calcific deposit. Weigert rubberband stain. Ca   =   calcium. (d) Aortic valve repair, with "reefing" of the complimentary margins of 2 of three cusps, with running, white Gortex (PTFE) sutures (red arrows). Procedure was abased afterwards the intraoperative TEE showed persistent aortic incompetence.

 (a) Reproduced with permission from Ref. [263]. (b) and (c) Reproduced with permission from Ref. [9].

The complications of mitral and AV reconstruction and repair are summarized in Table 13.ix.

Table xiii.9. Complications of Mitral and Aortic Valve Repair

Mitral Aortic
Early Unsatisfactory repair/valve incompetence
Left ventricular rupture
Injury to circumflex coronary artery
Perforation of leaflet tissue
Atrioventricular disruption (tear)
Pericardial hemorrhage/tamponade
Disruption of papillary muscle tip related to synthetic chordae tendinae
Infective endocarditis		 Unsatisfactory repair/valve incompetence
Cusp perforation
Missed fenestration
Perforation at base of anterior mitral leaflet
Hematoma
Fistula-aorta to right ventricle
Infective endocarditis
Late Recurrence of valvular incompetence
Valvular stenosis (due to pannus)
Annuloplasty band dehiscence
Infective endocarditis		 Recurrence of valvular incompetence or stenosis
Patch dehiscence (after cusp elongation)
Aortic cusp retraction
Pseudoaneurysm (aortic valve conserving procedures)
Thromboembolism
Infective endocarditis

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Anesthetic Considerations for Transcatheter Tricuspid Valve Repair

Jonathan 1000. Zoller Doc , Stephen H. Gregory Physician , in Journal of Cardiothoracic and Vascular Anesthesia, 2022

The development of transcatheter approaches for heart valve repair and replacement procedures accept revolutionized the field of structural cardiology and cardiac anesthesiology. With the recently reported benefits of transcatheter mitral repair procedures, at that place has been increasing focus on transcatheter tricuspid repair technologies. Currently, there are multiple transcatheter tricuspid repair devices that are undergoing feasibility testing, and each device has its own unique procedural considerations. This review discusses the coldhearted direction of transcatheter tricuspid repair by describing the causes of tricuspid regurgitation, the currently available transcatheter tricuspid repair devices, the procedural considerations relevant to the cardiac anesthesiologist, and pearls for proper intraprocedural image guidance via transesophageal echocardiography.

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Microbiological problems and biofilms associated with Mycobacterium chimaera in heater–libation units used for cardiopulmonary bypass

J. Walker , ... 1000. Chand , in Journal of Infirmary Infection, 2022

Clinical features and diagnosis

A number of investigations have demonstrated an increased hazard of invasive M. chimaera infection in patients who have undergone cardiothoracic surgery, particularly valve replacement or repair [1,four,44] . Although infections post-obit coronary artery bypass grafts, vascular grafts, centre transplant, and left ventricular help devices have been identified, adventure assessment suggests that heart valve repair and replacement bear the highest adventure [70]. A number of disseminated infections and secondary focal infections such every bit discitis take been reported [iv,44,seventy]. Patients affected have been primarily but not exclusively adults with a median age of 61 years (range: 36–76) which may reflect the age of those probable to require valve replacement surgery [4,44]. The interval from surgery to diagnosis has ranged from three months to vi years with a median interval of 17–18 months [1,four,70].

Estimated chance of infection varies, in role a likely reflection of under-ascertainment of cases [4]. Estimates from affected centres in Switzerland and the U.s. range from 1 per 100 to 1 per 1000 [i,56,71]. In England, national run a risk cess was possible through access to national health datasets. This identified an overall risk per patient undergoing centre valve surgery of 1 in 5000 between 2007 and 2022, although rising over time to reach ane in 2000 in 2022 [72].

Patient consequence has been described as poor, which is probably multifactorial from late diagnosis and treatment, intrinsic drug resistance of M. bubble biofilm which may hinder the penetration, and action of antimicrobials in the cardiac and pulmonary tissue [44,73].

Mycobacterium chimaera may likewise be misidentified, which could result in an underestimation of the number of cases. Thou. chimaera and M. intracellulare are genetically similar and most commercially bachelor laboratory assays cannot differentiate Thou. chimaera from Thousand. intracellulare. When 149 Thousand. intracellulare isolates were reanalysed using 16S rRNA sequencing, 63% of them were found to be Grand. chimaera [74]. Reanalysis of Chiliad. intracellulare isolates from relevant sites in cardiothoracic patients may effect in an increment in M. chimaera cases.

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