Individuals with chronic ischemic mitral regurgitation who undergo mitral valve replacement show significantly superior exercise performance up to almost 3½ years after the operation when compared with those who have restrictive mitral valve annuloplasty, according to a study in the June issue of the Journal of Cardiovascular Surgery. (J. Thorac. Cardiovasc. Surg. 2015 [doi:10.1016/j.jtcvs.2015.03.003]).
Doctors at three institutions in France, Italy, and the United Kingdom set out to predict what factors determined long-term functional capacity in patients with chronic ischemic mitral regurgitation (CIMR) who had either mitral valve replacement (MVR) or annuloplasty. They performed a retrospective analysis of 121 patients with significant chronic mitral regurgitation, 62 of whom had restrictive mitral valve annuloplasty and 59 of whom underwent MVR between 2005 and 2011. All the subjects had a resting echocardiography and a 6-minute treadmill test before their procedures and again at an average of 41 months afterwards. The MVR group walked an average of 37 meters farther at the postoperative stress test, whereas the annuloplasty patients walked on average 24 meters less than their preoperative test.
“The most important finding of this study is that, in patients with CIMR who underwent mitral valve surgery, the improvement in functional capacity at long-term follow-up is mainly related to the type of treatment and to the mitral valve hemodynamic performance, as expressed by changes in IEOA [indexed effective orifice area] during exercise,” reported lead author Dr. Carlo Fino of the Bristol (England) Heart Institute and Pope John XXIII Hospital in Bergamo, Italy, and his colleagues. Investigators from Hospital Dupuytren in Limoges, France, also participated.
The study noted inconclusive results of previous reports of patients treated for mitral regurgitation: the Cardiothoracic Surgical Trials Network study that showed similar 1-year outcomes among patients who had either MVR or annuloplasty (N. Engl. J. Med. 2014;370:23-32) ; an earlier study that showed annuloplasty patients may develop functional mitral stenosis with decreasing functional capacity (J. Am. Coll. Cardiol. 2008;51:1692-1701); and Dr. Fino and colleagues’ previous work that showed worse hemodynamics in annuloplasty patients, compared with MVR counterparts (J. Thorac. Cardiovasc. Surg. 2014;148:447-53).
Other comparative measures the latest study evaluated were: change in exercise indexed effective orifice area, increasing from 1.3 to 1.5 cm2/m2 in the MVR group vs. 1.1 to 1.2 cm2/m2 in the annuloplasty group; change in mean mitral gradients from rest to exercise, which increased significantly in both groups – from 4.3 to 9 mm Hg in the replacement group and 4.4 to 11 mm Hg in the annuloplasty group; postoperative cardiovascular events – 8% in the MVR group and 21% in the annuloplasty population; and follow-up survival – 88% for MVR vs. 83% for annuloplasty.
The annuloplasty patients received either a Carpentier-Edwards Physio ring (71%) or Carpentier-Edwards Classic ring (29%); Edwards Lifesciences. The MVR group received either a biological or mechanical prosthesis, although the study did not report how many of each. All patients had associated coronary bypass grafting surgery and all achieved complete revascularization. The MVR and annuloplasty groups were similar in terms of demographics and cardiac function, although a higher percentage of patients in the annuloplasty group had severe mitral regurgitation preoperatively – 41% vs. 32% in the MVR group.
Procedures like annuloplasty that aim to restore ventricular geometry or target the subvalvular mechanism “seem to be promising but they require further scientific evidence,” Dr. Fino and his coauthors said. They suggested that until 24-month results from the Cardiothoracic Surgical Trials Network are available, MVR with chordal sparing might be a “reliable option” for patients with chronic ischemic mitral regurgitation.
The authors had no disclosures.