DK2985_C000 1..28 - AlSharqia Echo Club

Mitral Valve Replacement and Repair 439Table 18.4Summary of the Role of TEE in Patients Undergoing Mitral Valve SurgeryImportanceBefore the procedureSee Table 13.1 for the role of TEE in cardiac surgeryEvaluate left atrial dimension, presence of unsuspected thrombusin LA and LAAConfirm the mechanism of mitral dysfunction (importance ofloading conditions)Evaluation of the severity of pulmonary hypertension andtricuspid regurgitationDuring CPBSee Table 13.1After CPBSee Table 13.1Evaluate result of repair or replacementRule out SAM and LVOT obstructionIn the intensive care unitSee Table 13.1Anticipation of difficult valve repair with possible modificationof the surgical approach, removal of thrombusConfirmation of reparability or replacementTricuspid annuloplasty may be considered with modification ofthe surgical approachEarly detection and correction of prosthetic dysfunction orsuboptimal repairSAM will modify the medical approach and could lead tosurgical reinterventionNote: CPB, cardiopulmonary bypass; LA, left atrium; LAA, left atrial appendage; LVOT, left ventricular ourflow tract; SAM, systolic anterior motion;TEE, transesophageal echocardiography.repair: perfusion pressure is maintained ,40 mmHg toprevent myocardial edema. The left atrial retractorblades are positioned and pump aspirators are used toaspirate left atrial blood during surgery.Once the surgeon has determined the mechanism ofMR, specific techniques of repair will be performed tocorrect the pathological valve.C. AnnuloplastyB. Valve AnalysisMitral valve functional analysis is then performed. This isof critical importance in valve reconstruction, andshould correlate with the perioperative TEE examination.There are three possible mechanisms responsible for MR:type 1—normal leaflet motion, type 2—increased leafletmotion, and type 3—restricted motion. Despite the factthat there are numerous possible valve lesions, they canalways be categorized into these three functional groups.Surgical valve analysis is then systematically performedwith specifically designed hooks. The P1 scallopof the valve is taken as the reference point and delicatelystretched with the left hand hook. The right hand hookwill alternatively evaluate the posterior leaflet P2 and P3scallops for prolapse or restriction which is defined as acoaptation plane above or below the plane of the nativeannulus of the mitral valve, respectively. Then, attentionis given to the anterior leaflet A1, A2, and A3 scallopsand finally to both anterolateral and posteromedian commissuresdefined by their fan shaped chords (Fig. 18.33).The annuloplasty ring has four functions: (1) to restorenormal annular geometry, (2) to prevent further annulardilation, (3) to decrease tension of sutures on mitral leafletsand annulus, and (4) to increase mitral valve coaptationsurface. There are complete and incomplete annuloplastyrings (Fig. 18.34). All rings are associated with an excellentclinical outcome. In ischemic MR, experimental andclinical studies support the use of complete remodellingannuloplasties in order to provide circumferentialsupport. In degenerative etiologies, posterior bands havebeen associated with good results, the anterior part ofmitral annulus being naturally fixed by the left and rightfibrous trigone and the aortic annulus.The ring size isselected with specifically designed templates whichmeasure the intercommissural distance or the intertrigonaldistance and the surface area of the anterior leaflet dependingon the model of ring selected.In degenerative MR, avoidance of an annuloplasty ringhas been related to an increased recurrence rate of MR.However, in the case of an active acute bacterial endocarditis,a ring annuloplasty can be avoided in order to avoid