Point-Counterpoint: Aortic Valvular Disease–PCI or Surgery?

Alain Cribier, MD, Chief, Cardiology, Charles Nicolle Hospital, Rouen, France.

Robert Guyton, MD, Chief, Cardiothoracic Surgery, Emory University School of Medicine, Atlanta, Ga.

Is there enough evidence to prove the safety/efficacy of percutaneous repair/replacement for aortic valve disease?

Cribier: The percutaneous techniques used today have demonstrated good safety and efficacy in the short- and mid-term, whichever valve (Edwards or Corevalve) and approach (transfemoral or transapical) are used. Procedural success is >90%, and adverse events, such as stroke and acute myocardial infarction, are low and acceptable in the high-surgical-risk subset of patients considered for transcatheter implantation.

 Mortality at one year is significantly reduced, with deaths attributed to comorbidities.

No bioprosthesis dysfunction has been reported. Little is known concerning very long-term results as few patients have reached more than three years of follow-up. The longest follow-up is five years in a patient implanted with the first-generation Edwards valve in Rouen, France, in 2003.

No valve deterioration has been reported in that patient, and the functional results have been excellent.

Guyton: Emerging evidence indicates that percutaneous replacement of stenotic aortic valves may be safe and effective in selected patients.

To date, however, the data support the use of these devices in patients who are at high risk for open surgical procedures.

The long-term durability of percutaneous aortic valves is not established.

Patient selection: Which characteristics should drive the choice between transcatheter or open surgical procedures?

Cribier: The current European and U.S. recommendations (EACT/ESC and FDA) clearly state that transcatheter valve implantation should be limited to patients at high surgical risk. This risk is generally evaluated by the Society of Thoracic Surgeons mortality risk score or logistic EuroSCORE, as well as good clinical sense.

 In addition, the cardiologist and the cardiac surgeon must reach consensus.

Old age alone is not a contraindication for surgery in patients at normal risk.

Guyton: In a patient who is a good candidate for an open surgical procedure, a 1% to 2% mortality rate is expected, as well as a stroke rate in the 1% range. Durability of 10 to 20 years for a biologic valve, depending on the age of the patient, also is expected.

Percutaneous valves have not yet achieved similar low rates of mortality or stroke in any large comparative randomized study and have certainly not demonstrated the durability of characteristics expected of the standard aortic valve replacement.

Currently, percutaneous valves should be reserved for patients who have a predicted operative mortality rate above 5%, and the patient should be carefully advised that durability has not been established.

Indications: Which modality is more appropriate in a patient with asymptomatic aortic stenosis?

Cribier: Patients who are asymptomatic should not receive valve replacement, except in the case of extremely severe disease that has been evaluated by echocardiography and an abnormal response to stress test indicating a decrease in aortic blood pressure at exercise.

Guyton: Medical therapy is generally the most appropriate method of treatment in patients with asymptomatic aortic stenosis.

If an asymptomatic patient develops LV dysfunction and pulmonary hypertension, then interventional therapy may be appropriate.

 In patients with an open surgical risk of <5% for stroke or death, standard aortic valve replacement is appropriate. In patients with an open surgical risk greater than 10% and who are good candidates for percutaneous therapy, a percutaneous valve is considered reasonable and is probably preferred.

An important concern is the possibility that the ease of device insertion and the relatively low risk will lead to the use of percutaneous valves in minimally symptomatic patients without randomized trials demonstrating benefit, thus following the pathway blazed by percutaneous coronary intervention.

Within five years, will the predominant method of aortic valve repair/replacement be percutaneous or surgical therapy?

Cribier: No one can currently answer this question.

The general feeling is that the indications for transcatheter valve implantation will expand if the current positive results are confirmed in large-scale trials.

The ongoing U.S. randomized trial PARTNER-US, in which more than 1,000 patients are receiving the Edwards valve, surgery, or medical treatment alone, will provide crucial data.

Elderly patients who are otherwise healthy will be among those who will benefit from an expanded indication.

However, I believe that surgical therapy will remain the predominant method within five years.

I am being cautious because there is a lack of data concerning the long-term durability of the devices and a lack of information about the safety/efficacy of transcatheter valve procedures in comparison with surgery. Both of these areas should be addressed by PARTNER-US.

Meanwhile, we must avoid the uncontrolled expansion of percutaneous valvular procedures. I am unconvinced about the future predominance of the transapical approach vs. the transfemoral approach.

With continuously evolving technical improvements and, in particular, the reduction in device profile, the transfemoral approach will likely be offered to an increasing number of patients worldwide as a less invasive "stent-like" procedure.

 However, I would not recommend downsizing the profile to <12 F. Such a reduction in size would jeopardize the quality of both stent (resistance to compression, circumferential opening) and bioprosthesis. A decrease to 18 F has already made the transfemoral approach feasible in about 80% of cases.

Guyton: I expect that approximately half of all aortic valve replacements will be percutaneous and half will be via open surgical techniques in five years.

One must not ignore the transapical technique, which is a hybrid combining percutaneous and open surgical techniques.

If the transapical technique can be refined so that the patient has a non–rib-spreading thoracotomy, or microthoracotomy, and hospitalization averaging fewer than three days, the transapical technique could become the dominant mode of aortic valve replacement.

What are the characteristics of an ideal device for percutaneous replacement in aortic valvular disease?

Cribier: An ideal device should offer at least the mechanical properties and durability found with current surgical valves, accompanied by similar or improved safety and efficacy. Among the ideal characteristics:

• A low profile allowing its use in the majority of patients regardless of the approach.
• Optimal stability within the aortic orifice.
• Optimal hemodynamic results (gradient and valve area).
• No coronary occlusion.
• No interference with mitral valve function.
• No contact with the interventricular septum and its bundle.
• Optimal circumferential opening to limit the risk of mid- or long-term valvular dysfunction regardless of the degree and distribution of native valve calcification.
• No or minimal paravalvular regurgitation.

Guyton: The ideal device for percutaneous replacement in aortic valvular disease should have the following attributes:

• Deliverable with a catheter size ≤12 F.
• Able to traverse the aortic arch with minimal trauma to prevent atheroembolism.
• Echogenic and radiopaque for ease in deployment.
• Retrievable so that an imperfect deployment can be corrected.
• Able to compensate for extremely calcified aortic valves with a "forgiving" cuff to prevent aortic insufficiency in stenotic disease.
• Able to accommodate up to 3.5 cm aortic annuli in aortic insufficiency.
• Demonstrated durability averaging at least 10 years or, failing that, able to be replaced at least twice with five-year durability.
• Should not require any anticoagulation or immunosuppression therapy.

Disclosures:

• Dr. Cribier reports serving as a consultant for Edwards Lifesciences.
• Dr. Guyton reports no relevant conflicts of interest.

（source：www.tctmd.com）