The minimally invasive MitraClip<sup>™</sup> procedure for mitral regurgitation under general anaesthesia: immediate effects on the pulmonary circulation and right ventricular function
A relatively new minimally invasive cardiological procedure, called the MitraClip<sup>™</sup>, does not require sternotomy and may have a number of advantages compared with open mitral valve surgery, but its acute impact on the pulmonary circulation and right ventricular function during general anaesthesia is unclear. We prospectively assessed the effects of the MitraClip procedure in 81 patients with or without pulmonary hypertension (defined as mean pulmonary artery pressure > 25 mmHg), who were anaesthetised using fentanyl (5 μg.kg<sup>–1</sup>), etomidate (0.2–0.3 mg.kg<sup>–1</sup>), rocuronium (0.5–0.6 mg.kg<sup>–1</sup>) and isoflurane. Placement of the MitraClip led to a 60% increase in mean (SD) right ventricular stroke work index (from 512 (321) to 820 (470) mmHg.ml.m–2, p < 0.0001), while mean (SD) pulmonary vascular resistance index decreased by 24% (522 (330) to 399 (244) dyn.s.cm<sup>–5</sup>, p < 0.0001), and mean (SD) pulmonary artery pressure decreased by 10% (30 (8) to 27 (8) mmHg, p < 0.0001). Patients with pulmonary hypertension experienced a similar decrease in mean pulmonary artery pressure compared with those without, and they also had a slight reduction in mean (SD) pulmonary artery occlusion pressure (22 (6) down to 20 (6) mmHg, p = 0.044). We conclude that successful MitraClip treatment for mitral regurgitation acutely improves right ventricular performance by reducing right ventricular afterload, regardless of whether patients have pre–operative pulmonary hypertension.