‘Life is short, the art (of medicine) long’…. Hippocrates
Modern medicine is emerging at a rapid pace. Every day, we learn about new lesser invasive treatment modalities which provides our patients with superior safety and shorter stay in the hospital. Implantation of artificial valves through skin known as ‘percutaneous approach’ is a great example of one such technique which has now widely been accepted as standard of care for treatment of Aortic Stenosis (tight heart valve). A number of similar percutaneous technologies have emerged in recent past as an alternative to open heart surgery for treatment of leaky heart valves.
Mitral regurgitation [MR] is amongst the most common heart valve disease affecting around 10% of population above age of 75 years. It occurs due to leaky mitral valve resulting in an abnormal backflow of blood from the lower chamber of heart to upper on the left side. This can occur due to structural or functional dysfunction of the valve apparatus. This abnormal reflux of blood has potential of causing hemodynamic compromise due to reduction in forward cardiac output (forward blood flow) and eventually leading to congestive heart failure in chronic cases.
The treatment of choice for severe symptomatic leaky mitral valve is its repair or replacement by an open heart surgery. However, a large number of our patients are denied surgery due to high operative risk. A European analysis in 2007 demonstrated that ∼50% of patients with severe symptomatic MR were denied open surgery mostly due to advanced age, impaired systolic function of heart (weak heart pumping) and other multiple co-morbidities. In another study of octogenarians undergoing mitral valve surgery, the reported mortality and morbidity was 17.0% and 35.5%, respectively. This has warranted the need for lesser invasive treatment strategies for mitral regurgitation.
These treatment modalities are broadly classified on the basis of target component of mitral valve apparatus. The most widely used technique is edge-to-edge repair of leaflets of a degenerated mitral valve using a clip. MitraClip system [see picture] was approved by the US Food and Drug Administration (FDA) in October 2013 for use in patients with symptomatic degenerative MR who are at increase risk for open heart surgery. This system consists of a clip device, a delivery system, and a catheter guide through which the device is introduced into the left upper chamber of heart through vascular access in the groin.
The patient selection, however, is important. It is indicated in patients who have high operative mortality risk, an extensively calcified aorta, frailty, hostile chest, severe liver dysfunction, severely elevated pressure in the lungs, cancer, chemotherapy, AIDS, right heart dysfunction, and severe dementia. A number of clinical studies have been published looking at outcome of this clipping technique. EVEREST-II trial is a randomized controlled trail which showed that repair of mitral valve through this approach was less effective than surgery in reducing degree of leakiness but that it has superior safety and similar clinical outcomes after a 12 month follow up. The potential complications associated with this procedure include bleeding at the puncture site in groin, collections of fluid around heart, myocardial infarction, irregular heart rhythm, stroke or in-hospital death. In one study, these complications were noted to occur in around 25% of patients out of which bleeding was most frequent, seen in 12.8%. In-hospital death, stroke or heart attack occurred in only 2.2, 0.9, and 0% patients, respectively.
In summary, percutaneous catheter based mitral valve repair has been evolving as a therapy for patients who are at high surgical risk. Many short-term clinical studies have demonstrated safety and efficacy of this procedure although long-term trials are still ongoing. The newer interventions other than leaflet repair are expected to hit the market in near future. This is an exciting era of an emerging technology, which will ultimately broaden the spectrum of patients with leaky heart valves who can be successfully treated without an open-heart surgery.
By: Reminder Meet Singh, M.D
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