Evolution and results of aortic valve surgery, and a ‘disruptive’ technology

ENTER THE PERCUTANEOUS DEVICES

In this issue of the Journal, Dr. Singh and colleagues review the options for percutaneous aortic valve insertion in high-risk patients, and their potential outcomes.⁷ But as the authors note, much study still needs to be done regarding this technique.

In an initial feasibility study of 55 high-risk or inoperable patients undergoing transfemoral aortic valve insertion under a protocol approved by the US Food and Drug Administration (FDA), the mortality rate was 7.2% and the stroke rate was 9.2%. For the FDA-approved study of 40 patients underoing transapical valve placement, the mortality rate was 17%, but no immediate strokes occurred in successful procedures, even though most of these patients were not eligible for transfemoral aortic valve insertion because of peripheral vascular disease.⁶ Clearly, based on our data,¹ the presence of peripheral vascular disease added to the risk of death.^1,6

Even if the issues surrounding percutaneous valve insertion remain unresolved for early versions of the devices, one important benefit is that more people who would benefit from treatment are being referred for evaluation. At Cleveland Clinic, we have already noticed that sick patients who would not previously have been referred for surgery are now being referred because of the new technology, although only about 20% of these are eventually enrolled in the PARTNER study. A further 20% undergo conventional open surgery, 20% undergo balloon valvuloplasty, and the remainder are too sick, die during evaluation, or refuse intervention.⁶ Indeed, none of the patients who underwent high-risk open surgery died.⁶

Although this new, “disruptive” technology was introduced for patients for whom surgery would pose an unacceptably high risk, it is inevitable that, with further improvements in prosthetic valves and the ways to insert them, percutaneous valve insertion will make inroads in the treatment of aortic valve stenosis.

While most disruptive technologies are cheaper than the technologies they displace, this may not be the case with percutaneous valve insertion: a standard aortic heart valve costs $2,500 to $6,000, whereas percutaneously delivered valves cost $30,000. The hospital stay may turn out to be a little shorter, which may help control the overall cost. But while the hospital stay after percutaneous insertion may be shorter than for surgical valve replacement (3–5 days vs 5–7 days), percutaneous valve insertion is currently labor-intensive and requires a team of 25 to 30 people, compared with five or six for open repair.

Percutaneous valve insertion offers selected high-risk patients one of the most beneficial treatments in cardiovascular medicine that they potentially would never have benefited from—ie, improved quality of life, and more years of life. It has great potential, but the problems of procedural safety and of access to treatment still need to be overcome.