A systematic search of the literature identified 12 articles that were assessed. No randomized controlled study was identified and none of the observational studies report results from an adequate control group of patients with pharmaceutical treatment only. The number of patients per study center was low, the follow up time relatively short and there was a loss of patients at follow up. The studies are not blinded, except for attempts regarding echocardiography. The manufacturing company has participated in planning of the studies and has participated at all interventions. Some authors of the studied publications have been consultants and received research grants.
MitraClip® was successfully positioned in 92-100% of the interventions. The incidence of severe adverse events was considered low. All studies showed significant improvements in quality of life. The year after MitraClip® 10-31% of the patients were hospitalized. Mortality within 30 days was 3% and after 12 and 24 months 13% and 11% respectively. Before MitraClip® 90-100% patients were classified as NYHA III/IV with a significant improvement after MitraClip®. Significant improvements of 6-MWT and NT-proBNP were found.
Before MitraClip® 98% of the patients were assessed as MR grade III/IV. After the intervention the MR assessment was significantly improved to 37% as MR grade I, 49% as MR grade II and 15% as MR grade III/IV. A few patients got worse. No stenosis was reported. Echocardiography measurements indicated reverse remodeling of the heart and in some articles also an improvement in heart function.
Without any study with an adequate control group and due to low quality of the assessed observational studies the level of evidence according to GRADE was assessed as very low ⊕. The questions asked could not be answered whether intervention with MitraClip®, compared with medical treatment of patients with severe mitral
insufficiency, results in improved quality of life and heart function or reduced hospitalization and mortality. More research is necessary for further evaluation of MitraClip®.
This Health Technology Assessment has been conducted by Magnus Settergren, specialist in cardiology, Peter Svenarud , specialist in thoracic surgery, and Bengt Ullman, specialist in cardiology in cooperation with Claes Lennmarken and Elisabeth Persson, both medical advisers at the HTA-center in Stockholm County Council-Region Gotland, Sweden.
Included and excluded articles
Report in Swedish