A shows the mitral annulus from the cardiac apex and B shows with the free walls of the right atrium and ventricle removed. A guidewire through the coronary sinus enters a basal septal perforator vein and traverses a short distance of septal myocardium. Wire 1 follows a right ventricular (RV) cerclage trajectory into the right ventricular outflow tract, and Wire 2 a longer trajectory to re-enter the right atrium directly. The guidewire is replaced with a suture, and tension is applied to both ends and fixed near the coronary sinus ostium. C to E show X-ray fused with MRI (XFM) procedure guidance. The MRI-derived contours include left ventricular (LV) and RV endocardium (blue and yellow), LV epicardium (green), and the aortic root (red). D shows live X-ray fluoroscopy and E shows the corresponding XFM display. The guidewire tip (white arrow) crosses the septal myocardium and re-enters the right ventricle. Registration is maintained even when the table or gantry moves. F shows the discordant planes of the mitral annulus (blue) and cerclage annuloplasty (red). Necropsy findings are shown immediately after right ventricular (G) and right atrial (H) cerclage with the RV free wall removed. In G, the suture (arrow) emerges from the septum and returns to the right atrium across a tricuspid commissure. In H, a suture emerges (arrow) near the cavotricuspid isthmus, alongside the coronary sinus end of the same suture (dotted arrow). A, B, and F are courtesy of Lydia Kibiuk, National Institutes of Health Medical Arts.

(A and B) A typical great cardiac vein configuration passing outside a circumflex artery branch. (C) Cerclage would compress the underlying artery. (D) A protection device along the cerclage suture redistributes compressive forces away from coronary artery. (E to H) circumflex coronary artery pressure during cerclage tension without (E and G) and with (F and H) a protection device in place. (E) Angiographic stenosis (arrow) induced by cerclage and (F) the same segment during cerclage tension with a protection device (dashed arrow) in place. (G and H) Distal coronary artery pressure (Pd, depicted in green, axis on left, in millimeters), the aortic pressure (Pa) in red, and their ratio in yellow (axis on right, displayed as fractional flow reserve). Without a protection device (G), the distal coronary pressure falls by more than half when cerclage tension (400 g) is applied. (H) With the protection device in place, there is no distal pressure drop after cerclage tension is introduced (dotted arrow) until tension is sufficiently high (solid arrow) to impede mitral inflow. A to D are courtesy of Lydia Kibiuk, National Institutes of Health Medical Arts.

(A) Progressively increased cerclage tension reduces the annular septal-lateral dimension, perpendicular to the line of mitral coaptation. (B) With progressive tension, the decline in cerclage diameter is directly related to the decline in septal-lateral dimension. (C) Reduced cerclage diameter is directly related to the reduction in mitral valve tenting area, an index of mitral regurgitation.

A shows the loops before and B to D show the loop after progressive application of cerclage tension in naive swine. There is no significant change in the end-diastolic (upper slope) and end-systolic (lower slope) pressure–volume relationships as tension is introduced. Tension (600 g) was found to reduce annular circumference sufficiently to impede transmitral inflow. In this animal, cerclage does not acutely alter ventricular volumes.

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(A and C) show mitral regurgitation before and (B and D) after application of cerclage tension. Arrowheads 1 and 2 indicate the anterior and posterior mitral annulus, respectively. Arrowheads 3 and 4 indicate the anterior and posterior course of the cerclage annuloplasty. Arrows indicate the twin jets of mitral regurgitation in this magnetic resonance imaging (MRI) in an animal with a regurgitant fraction of 0.43. After tension was applied, the regurgitant fraction fell to 0.08, and jets were no longer visible. Note the anterior displacement of Point 4 and its altered configuration in relation to Point 2 (animated in Online Video 1). Note also that regurgitant jets of dephased spins in steady-state free precession MRI under-represent mitral regurgitation compared with echocardiography. (C and D) show combined motion (tagged) and velocity-encoded MRI during systole before (C) and after (D) application of cerclage tension in another animal, animated in Online Video 2. Mitral regurgitation is evident as a blue jet in (C, black arrow) and nearly extinguished in (D). The posterior cerclage wire (black spot indicated by white arrow) is displaced toward the septum when tension is applied. Late gadolinium enhancement and reduced myocardial contraction are evident from prior posterobasal infarction.

A shows the quantitative measures and B shows the qualitative measures. MRI = magnetic resonance imaging.

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The time scale is normalized for a single cardiac cycle beginning with the QRS gating signal for magnetic resonance imaging (MRI). Measurements before cerclage tension is applied are indicated by a solid line; measurements afterward are indicated by a dotted line. Cerclage reduces annular circumference (A), commissural width (B), and septal-lateral distance (C) but increases annular height to commissural width ratio (AHCWR, a measure of annular flattening, D). All vary throughout the cardiac cycle and continue to vary despite application of annular tension. (E and F) depict the annulus (black) and leaflet (colored) morphology derived from MRI before (E) and after (F) application of cerclage tension. The posterior annulus (arrow) is displaced caudally toward the posterior papillary muscle when cerclage tension is applied. This is animated in Online Videos 3 and 4. RR = interval between electrocardiogram R waves.

The combined diameter of the 2 structures remains constant throughout the cardiac cycle. During diastole, the anterior mitral leaflet is relatively unconstrained. During systole, the outflow tract enlarges and displaces the anterior mitral valve (MV) leaflet posteriorly (*p < 0.01 vs. diastole). This appears to enhance leaflet coaptation and valve function. AV = aortic valve; CM = centimeters.

(A) A pressurized venogram in a patient undergoing cardiac resynchronization therapy. A basal septal perforator vein was evident (arrow) in all 8 patients with evaluable angiograms. (B) A computed tomography angiogram showing a basal septal perforator vein (arrows) apparently suitable for cerclage.