Dacron Skirt Reconstruction of the Left Ventricular Outflow Tract: Extending the Capabilities of a Valved Conduit.

Aortic root reconstruction in the setting of redo aortic valve procedures or infective endocarditis may be technically challenging, particularly because of variable destruction or distortion of the left ventricular outflow tract. Homograft aortic root replacement is an excellent option for aortic root abscesses but is limited by homograft availability. We describe a simple technique of a bioprosthetic valved conduit constructed on the table using a Dacron (DuPont, Wilmington, DE) skirt below the valve.

Complex Tricuspid Valve Repair in Patients With Pacer Defibrillator-Related Tricuspid Regurgitation.

Tricuspid valve regurgitation in patients with heart failure or in those undergoing complex cardiac operations is associated with increased morbidity and mortality. We report our results with a technique of repairing the tricuspid valves while retaining the pacer defibrillator lead. Patients had tricuspid valve repairs that included repositioning of the pacer defibrillator lead, approximation of septal and inferior/posterior leaflets in a modified cleft repair, and implantation of a tricuspid annuloplasty ring.

Geometric perturbations in multiheaded papillary tip positions associated with acute ovine ischemic mitral regurgitation.

Background: Novel surgical approaches are focusing on the "ventricular disease" of ischemic mitral regurgitation (IMR), to correct altered papillary muscle (PM) tip positions (apical displacement) and ameliorate leaflet tethering. Due to the anatomic complexity of the subvalvular apparatus, however, the precise geometric perturbations of the multiheaded PM tips associated with IMR remain uncharacterized.

Methods: In 6 adult sheep, we implanted 3 markers on each PM.

Determinants of evolution and progression of acute ovine ischemic mitral regurgitation.

Background And Aim Of The Study: The optimal treatment of moderate ischemic mitral regurgitation (IMR) remains contested. Thus, radiopaque markers were implanted on valvular structures to investigate the geometric and hemodynamic variables associated with the evolution and progression of acute ovine IMR.

Methods: Eight adult sheep underwent implantation of five radiopaque markers on the edge of the posterior mitral leaflet (PML), and five on the edge of the anterior mitral leaflet (AML).

Regional mitral leaflet opening during acute ischemic mitral regurgitation.

Background And Aim Of The Study: Diastolic mitral valve (MV) opening characteristics during ischemic mitral regurgitation (IMR) are poorly characterized. The diastolic MV opening dynamics were quantified along the entire valvular coaptation line in an ovine model of acute IMR.

Methods: Ten radiopaque markers were sutured in pairs on the anterior (A1-E1) and corresponding posterior (A2-E2) leaflet edges from the anterior (A1/A2) to the posterior (E1/E2) commissure in 11 adult sheep.

Effects of acute ischemic mitral regurgitation on three-dimensional mitral leaflet edge geometry.

Background: Improved quantitative understanding of in vivo leaflet geometry in ischemic mitral regurgitation (IMR) is needed to improve reparative techniques, yet few data are available due to current imaging limitations. Using marker technology we tested the hypotheses that IMR (1) occurs chiefly during early systole; (2) affects primarily the valve region contiguous with the myocardial ischemic insult; and (3) results in systolic leaflet edge restriction.

Methods: Eleven sheep had radiopaque markers sutured as five opposing pairs along the anterior (A(1)-E(1)) and posterior (A(2)-E(2)) mitral leaflet free edges from the anterior commissure (A(1)-A(2)) to the posterior commissure (E(1)-E(2)).

Effect of chronotropy and inotropy on stitch tension in the edge-to-edge mitral repair.

Background: Our prior studies suggest that mitral annular septal-lateral (SL) diameter is the chief determinant of "Alfieri stitch" tension, but hemodynamic parameters may also play a role. We approximated the central edge of the mitral leaflets with a miniature force transducer to measure tension (T) at the leaflet approximation point during inotropic and chronotropic stimulation.

Methods And Results: Eight sheep were studied under open-chest conditions immediately after surgical placement of a miniature force transducer to approximate the leaflets and implantation of radiopaque markers on the LV and mitral annulus (MA).

Tenting volume: three-dimensional assessment of geometric perturbations in functional mitral regurgitation and implications for surgical repair.

Background And Aim Of The Study: Functional mitral regurgitation (FMR) often complicates dilated cardiomyopathy (DCM), and portends a poor prognosis. Debate over the optimal treatment continues, underscoring the present incomplete understanding of the patho-anatomic mechanisms of this disease. Studies of mitral tenting volume and tenting area, and echocardiographic measures of abnormal apical systolic leaflet geometry have linked mitral leaflet deformation with subvalvular left ventricular (LV) remodeling in chronic ischemic MR.

Mitral leaflet remodeling in dilated cardiomyopathy.

Background: Normal mammalian mitral leaflets have regional heterogeneity of biochemical composition, collagen fiber orientation, and geometric deformation. How leaflet shape and regional geometry are affected in dilated cardiomyopathy is unknown.

Methods And Results: Nine sheep had 8 radio-opaque markers affixed to the mitral annulus (MA), 4 markers sewn on the central meridian of the anterior mitral leaflet (AML) forming 4 distinct segments S1 to S4 and 2 on the posterior leaflet (PML) forming 2 distinct segments S5 and S6.

Annular height-to-commissural width ratio of annulolasty rings in vivo.

Background: A "saddle-shaped" mitral annulus with an optimal ratio between annular height and commissural diameter may reduce leaflet and chordal stress and is purported to be conserved across mammalian species. Whether annuloplasty rings maintain this relationship is unknown.

Methods And Results: Twenty-three adult sheep underwent implantation of radiopaque markers on the left ventricle and mitral annulus.

Effects of paracommissural septal-lateral annular cinching on acute ischemic mitral regurgitation.

Background: Previous experimental studies demonstrated that central septal-lateral (SL) annular cinching (SLAC) abolishes acute ischemic mitral regurgitation (IMR), but whether localized cinching near the anterior (ACOM) or posterior (PCOM) commissure is equally effective is unknown.

Methods: Six adult sheep underwent implantation of 9 radiopaque markers on the left ventricle, 8 around the mitral annulus (MA) and 1 on each papillary muscle (PM) tip. Transannular SL sutures were placed at the valve center (CENT) and near ACOM and PCOM and externalized.

Mitral annular size predicts Alfieri stitch tension in mitral edge-to-edge repair.

Background And Aim Of The Study: Whilst increased 'Alfieri stitch' tension may reduce the durability of 'edge-to-edge' mitral repair, the factors affecting suture tension are unknown. In order to study hemodynamics and left ventricular (LV) and annular dynamics that determine suture tension, the central edge of the mitral leaflets was approximated with a miniature force transducer to measure leaflet tension (T) at the leaflet approximation point.

Methods: Eight sheep were studied under open-chest conditions immediately after surgical placement of a force transducer and implantation of radiopaque markers on the left ventricle and mitral annulus (MA).

Can the principles of evidence-based medicine be applied to the treatment of aortic dissections?

Surgical treatment of patients with acute type A aortic dissections has improved early survival from 10-20 to approximately 80%. Data supporting several other treatment recommendations in patients with aortic dissection, however, are less convincing. We hypothesized that applying strict principles of evidence-based medicine would invalidate most of the recommendations in these published papers.

Acute type A aortic dissection complicated by aortic regurgitation: composite valve graft versus separate valve graft versus conservative valve repair.

Objective: To clarify the merits of various surgical approaches, we studied the outcome after composite valve graft versus separate valve and graft replacement versus conservative valve treatment with replacement of the ascending aorta in patients with acute type A aortic dissection complicated by aortic regurgitation.

Methods: Between 1967 and 1999, 123 patients (mean age 56 +/- 15 years) underwent composite valve graft replacement (n = 21), separate valve and graft replacement (n = 20), or conservative valve treatment (n = 82 [commissural resuspension in 46]); follow-up averaged 6.5 years (95% complete).

Aorto-mitral annular dynamics.

Background: The aortic and mitral valves are coupled through fibrous aorto-mitral continuity, but their synchronous dynamic physiology has not been completely characterized.

Methods: Seven sheep underwent implantation of five radiopaque markers on the left ventricle, 10 on the mitral annulus, and 3 on the aortic annulus. One of the mitral annulus markers was placed at the center of aorto-mitral continuity (mitral annulus "saddle horn").

Edge-to-edge mitral valve repair without ring annuloplasty for acute ischemic mitral regurgitation.

Background: Alfieri edge-to-edge mitral repair has been used clinically with ring annuloplasty to correct ischemic mitral regurgitation (IMR), but its efficacy without concomitant ring annuloplasty has not been described in this setting.

Methods: Seventeen sheep underwent implantation of 9 radiopaque markers on the left ventricle, 8 on the mitral annulus (MA), 1 on each papillary muscle (PM) tip, and 1 on the anterior and posterior leaflet edges near the anterior and posterior commissures. Alfieri repair was performed in 7 animals, and 10 were controls.

Ablation of mitral annular and leaflet muscle: effects on annular and leaflet dynamics.

Mitral annular (MA) and leaflet three-dimensional (3-D) dynamics were examined after circumferential phenol ablation of the MA and anterior mitral leaflet (AML) muscle. Radiopaque markers were sutured to the left ventricle, MA, and both mitral leaflets in 18 sheep. In 10 sheep, phenol was applied circumferentially to the atrial surface of the mitral annulus and the hinge region of the AML, whereas 8 sheep served as controls.

Alterations in left ventricular curvature and principal strains in dilated cardiomyopathy with functional mitral regurgitation.

Background And Aim Of The Study: Functional mitral regurgitation (FMR) is increasingly recognized as a left ventricular (LV) disease. Dilated cardiomyopathy (DCM) is commonly accompanied by FMR and reduction of LV torsion. Therapeutic targets for DCM include LV size reduction, altered LV shape, elimination of MR, and increasing LV torsion.

Ischemia in three left ventricular regions: Insights into the pathogenesis of acute ischemic mitral regurgitation.

Background: Acute posterolateral left ventricular ischemia in sheep results in ischemic mitral regurgitation, but the effects of ischemia in other left ventricular regions on ischemic mitral regurgitation is unknown.

Methods: Six adult sheep had radiopaque markers placed on the left ventricle, mitral annulus, and anterior and posterior mitral leaflets at the valve center and near the anterior and posterior commissures. After 6 to 8 days, animals were studied with biplane videofluoroscopy and transesophageal echocardiography before and during sequential balloon occlusion of the left anterior descending, distal left circumflex, and proximal left circumflex coronary arteries.

Tachycardia-induced cardiomyopathy in the ovine heart: mitral annular dynamic three-dimensional geometry.

Background: Ring annuloplasty has been used to correct annular dilatation and mitral regurgitation in dilated cardiomyopathy, but little is known about the dynamic precise 3-dimensional geometry of the mitral annulus in this condition.

Methods: Nine sheep had radiopaque markers sewn to the mitral annulus, creating 8 distinct segments beginning at the posterior commissure (segments 1-4, septal mitral annulus; segments 5-8, lateral mitral annulus). Biplane videofluoroscopy and transesophageal echocardiography were performed before and after rapid pacing (180-230 min(-1) for 15 +/- 6 days) sufficient to develop tachycardia-induced cardiomyopathy and mitral regurgitation.

Ischemia-induced malcoaptation of scallops within the posterior mitral leaflet.

Background And Aims Of The Study: The posterior mitral leaflet is divided into a variable number of scallops, and little is known about the role of scallopmalcoaptation in ischemic mitral regurgitation. The study aim was to assess whether acute ischemia in the posterolateral wall of the left ventricle would induce scallop separation that would contribute to mitral regurgitation.

Methods: Radio-opaque markers were surgically placed in the left ventricle, around the mitral annulus, and at three sites along the posterior mitral leaflet edge in eight sheep.

The effects of mitral annuloplasty rings on mitral valve complex 3-D geometry during acute left ventricular ischemia.

Objective: Annuloplasty rings are used to treat ischemic mitral regurgitation (IMR), but their exact effects on 3-D geometry of the overall mitral valve complex during acute left ventricular (LV) ischemia remain unknown.

Methods: Radiopaque markers were sutured to the mitral leaflet edges, annulus, papillary muscle tips, and ventricle in three groups of sheep. One group served as control (n = 5), and the others underwent Duran (n = 6) or Physio (n = 5) ring annuloplasty.

Is medical therapy still the optimal treatment strategy for patients with acute type B aortic dissections?

Objective: The optimal treatment of patients with acute type B dissections continues to be debated.

Methods: A 36-year clinical experience of medical and surgical treatments in 189 patients was retrospectively analyzed (multivariable Cox proportional hazards model) with respect to three outcome end points: all deaths, freedom from reoperation, and freedom from late aortic complications or death. Propensity score analysis identified 2 quintiles (quintiles I and II, consisting of 142 comparable patients) for further comparison of the effects of surgical versus medical treatment.

Atrial contraction and mitral annular dynamics during acute left atrial and ventricular ischemia in sheep.

In six sheep, radiopaque markers were placed on the left ventricle (LV), the mitral annulus, the left atrium (LA), and the central edge of both mitral leaflets to investigate the effects of acute LV ischemia on atrial contraction, mitral annular area (MAA), and mitral regurgitation (MR). Animals were studied with biplane videofluoroscopy and transesophageal echocardiography before and during balloon occlusion of the left anterior descending (LAD), distal circumflex (dLCX), and proximal circumflex (pLCX) coronary arteries. MAA and LA area were calculated from the corresponding markers.

Does profound hypothermic circulatory arrest improve survival in patients with acute type a aortic dissection?

Objective: No evidence exists that profound hypothermic circulatory arrest (PHCA) improves survival or reduces the likelihood of distal aortic reoperation in patients with acute type A aortic dissection.

Methods: Records of 307 patients with acute type A aortic dissection from 1967 to 1999 were retrospectively reviewed. The influence of repair using PHCA (n=121) versus without PHCA (n=186) on death and freedom from distal aortic reoperation was analyzed using multivariable Cox regression models.