"Keyhole" valve surgery shows striking benefits in patients with aortic stenosis unsuitable for surgery

22/02/2011

Transcatheter aortic valve replacement (TAVI) was associated with much better outcomes than standard care in patients with severe aortic disease unable to undergo surgery in the PARTNER trial.

Aortic stenosis is associated with a high rate of death (approximately 50% in the first two years after symptoms appear) among untreated patients. While surgical replacement of the aortic valve reduces symptoms and improves survival, at least 30% of patients are unable to undergo surgery because of advanced age, left ventricular dysfunction, or the presence of multiple coexisting conditions. For these patients, the less invasive procedure of transcatheter aortic valve replacement (TAVI) has been available since 2002. In this "keyhole" procedure a bioprosthetic valve is inserted through a catheter and implanted within the diseased native aortic valve. But until now there have not been any rigorous, evidence-based clinical data to substantiate the benefits of TAVI as compared to standard therapies.

In the PARTNER trial, 358 patients unsuitable for surgery were randomised to either transcatheter valve implantation or standard care, including balloon valvuloplasty. The study showed that that although strokes and major vascular complications were higher in the TAVI group in the first 30 days, at one year there were impressive reductions in the TAVI group for all-cause mortality (30.7% in TAVI vs 50.7% in untreated group) and the composite end point of death or repeat hospitalisation (42.5% vs 71.6% ).

The authors note that only five patients needed to be treated to prevent one death, and only three patients needed to be treated to prevent either a death or repeat hospitalisation.

The PARTNER investigators explain that "On the basis of a rate of death from any cause at one year that was 20 percentage points lower with TAVI than with standard therapy, balloon-expandable TAVI should be the new standard of care for patients with aortic stenosis who are not suitable candidates for surgery," the PARTNER authors conclude.

The trial, presented at the Transcatheter Cardiovascular Therapeutics (TCT) meeting in Washington DC, US, in September, has also now been published (N Engl J Med 2010;363:1597-1607). A second part of the trial comparing TAVI with surgical valve replacement in high-risk patients is still ongoing.

"Keyhole" surgery with the mitral clip as good as heart valve repair surgery

A catheter-mounted device, which acts as a clip to repair leaky heart valves, is a safe and effective alternative to open-chest surgery in selected patients with mitral regurgitation, according to the results of EVEREST II (Endovascular Valve Edge-to-Edge Repair Study). In addition, patients treated with the MitraClip® valve repair system were far less likely to experience a serious complication within 30 days of the procedure.

Lead investigator, Dr Ted Feldman (North Shore University Health System, Evanston, USA) said: "As clinicians, we have seen our patients transformed from highly symptomatic to highly functional with a catheter procedure – and without a long hospital stay or a long recovery period".

As with other percutaneous procedures, the MitraClip" device is threaded through the femoral vein in the groin and into the right atrium. A needle puncture in the wall separating the upper chambers of the heart enables the catheter to pass into the left atrium, where the clip is opened up. It is then passed through the mitral valve into the left ventricle. When the heart contracts, the flaps, or leaflets, of the mitral valve fall into the clip, which is then closed, pinning the edges of the leaflets together at their centres. The result is a bow-tie-shaped opening that permits blood flow from the left atrium to the left ventricle during relaxation of the heart, and enables the valve to close more effectively during contraction, rather than allowing leakage of blood backward into the left atrium.

The EVEREST II study was designed to evaluate the safety and effectiveness of the MitraClip" procedure in comparison with open-chest mitral valve surgery in 279 patients.

The primary safety end point (a combination of adverse events including death, major stroke, reoperation, urgent/emergent surgery, myocardial infarction, renal failure, and blood transfusions, among others) significantly favoured the MitraClip" at 30 days (9.6% in MitraClip group vs 57% in surgery group). The need for blood transfusions was the main driver of the safety end point, with a difference of 8.8% vs. 53.2%. The primary efficacy end point, the overall clinical success rate, was numerically higher in the surgery group (72.4% in MitraClip group vs 87.8% in surgery group).

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