Acute and chronic reduction of functional mitral regurgitation in experimental heart failure by percutaneous mitral annuloplasty

We sought to determine acute and chronic efficacy of a percutaneous mitral annuloplasty (PMA) device in experimental heart failure (HF). Further, we evaluated the potential for adverse effects on left ventricular (LV) function and coronary perfusion. Reduction of mitral annular dimension with a PMA device in the coronary sinus may reduce functional mitral regurgitation (MR) in advanced HF. Study 1: a PMA device was placed acutely in anesthetized open-chest dogs with rapid pacing-induced HF (n = 6) instrumented for pressure volume analysis. Study 2: in 12 anesthetized dogs with HF, fluoroscopic-guided PMA was performed, and dogs were followed for four weeks with continuing rapid pacing. Study 1: percutaneous mitral annuloplasty reduced annular dimension and severity of MR at baseline and with phenylephrine infusion to increase afterload (MR jet/left atrial [LA] area 26 ± 1% to 7 ± 2%, p < 0.05). Pressure volume analysis demonstrated no acute impairment of LV function. Study 2: no device was placed in two dogs because of prototype size limitations. Attempted PMA impaired coronary flow in three dogs. Percutaneous mitral annuloplasty (n = 7) acutely reduced MR (MR jet/LA area 43 ± 4% to 8 ± 5%, p < 0.0001), regurgitant volume (14.7 ± 2.1 ml to 3.1 ± 0.5 ml, p < 0.05), effective regurgitant orifice area (0.130 ± 0.010 cm2to 0.040 ± 0.003 cm2, p < 0.05), and angiographic MR grade (2.8 ± 0.3 device to 1.0 ± 0.3 device, p < 0.001). In the conscious state, MR was reduced at four weeks after PMA (MR jet/LA area 33 ± 3% HF baseline vs. 11 ± 4% four weeks after device, p < 0.05) Percutaneous mitral annuloplasty results in acute and chronic reduction of functional MR in experimental HF.