Lowering the Price to Pay for TAVI

Trying to decrease the risk of surgical or interventional cardiac procedures for patients with heart disease is a slow process. Forty to 50 years ago when valve replacement and coronary surgery were just beginning, operative risk was formidable, but accepted because there were no alternative therapies. Over time, operative risks have decreased many-fold as patient selection, technology, and “know-how” have improved. The same can be said for interventional cardiac procedures. Coronary stenting 20 years ago tried to steer between the Scylla and Charybdis of thrombosis and bleeding. Today, we still face those real monsters, but risk is less. We have learned, and risk has decreased over time.

Now we have new technology to treat patients with structural heart disease (especially aortic stenosis). Transcatheter aortic valve insertion (TAVI) has captured our attention. European registry data and the United States PARTNER I trial(s) indicate that the benefit of TAVI is unquestionable. In the randomized PARTNER I(B) trial comparing TAVI to ongoing “standard” medical therapy (is there any?) for aortic stenosis, mortality at 1 year was a whopping 20% less in the TAVI group and combining death and repeat hospitalization was even more striking at 28% less.¹ However, the early risk of TAVI cannot be overlooked. At 30 days, the mortality associated with the TAVI procedure was 5.0% vs. 2.8% for “standard” medical therapy, including balloon aortic valvuloplasty. Even more sobering is that the incidence of stroke was 6.7% vs. 1.7%. Forget that the benefit of TAVI at 1 year far outweighs not having TAVI — the risk, or price the patient has to pay “up front” for TAVI is real. The recently reported outcomes of the PARTNER I(A) cohort, in which patients were randomized to TAVI (via transfemoral or transapical route) or surgical valve replacement show that stroke rates were lower than in PARTNER IB, but they still exceeded surgical stroke risk. Once again, there is no free lunch.

A report in this issue of the Journal of Invasive Cardiology begins to address the price our patients have to pay for TAVI. The study pooled the results of 12 series of patients receiving TAVI.² Mortality at 1 month in patients treated with TAVI was 9.7% and procedural mortality was 2.4%. The authors conclude that these data compare favorably with the predicted surgical mortality, since EuroSCORE ranged from 12–28%.This may not be a fair benchmark — the surgical bar continues to be set high and note that in PARTNER 1(A), reported at the American College of Cardiology annual meeting this year, surgical mortality at 30 days was 6.7% in the intention-to-treat analysis and 8.0% in actual treatment analysis — despite STS scores of more than 11. As an aside, perhaps it is time to reevaluate our risk score analysis of surgical patients who need aortic valve replacement.

In the meta-analysis, almost half (40%) of causes of death within 30 days were from cardiac failure and cardiac arrest. Vascular and/or bleeding complications came in second (17% of deaths). Stroke was the third leading cause of mortality (11% of deaths). Perhaps most important is the overall death rate at 1 year — mortality in the TAVI group was 30.7% and “standard” therapy produced a mortality of 49.7%. This difference of 19% almost exactly reproduces the difference seen in the two groups in the randomized PARTNER I(A) trial. If there is “truth” in reproduction of data from disparate sources, this is a good example.

What can we learn from this aside from the obvious term mortality advantage that TAVI brings to our patients? The data point out that we need to be careful in selecting patients for TAVI and that we need better technology to deal with the early complications. By doing so, the 30-day price (mortality) might be decreased in relation not only to the procedure itself, but also in the high complexity of the patients (advanced age, renal dysfunction, lung disease, etc.) which is responsible for later mortality. Clearly, technical expertise of operators doing the TAVI procedure is paramount. Experience and catheter management can minimize tamponade, for example. But there is good news on the horizon. Innovative devices to reduce cerebral thromboembolism are in clinical trials. Candidly, the concept of an “acceptable” stroke rate for TAVI (or for cardiac surgery) should be zero. Second-generation, smaller devices that are more user-friendly to the iliac vasculature are already being studied and should reduce bleeding and other vascular complications.

Despite these technical advances, patient selection will become increasingly important in maximizing longer-term outcomes. In the report, after 30 days, only one-third of deaths were cardiac and two-thirds were due to comorbidities (respiratory disease, sepsis, renal failure, cancer and stroke). As the use of TAVI goes forward, it will be time to reassess who we are treating, and try to identify those patients who have a limited life expectancy even with TAVI. This report begins to give us data with which to approach this difficult clinical decision. It is a start, but we will need a lot more information so that we can accurately identify those patients for whom TAVI is the best option, and perhaps identify those better not treated with this new technology.

References

1. Leon MB, Smith CR, Mack M, et al., for the PARTNER Trial Investigators. Trans-catheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med 2010;363:1597–1607. Epub 2010 Sep 22.
2. Moreno R, Calvo L, Salinas P, et al. Causes of peri-operative mortality after transcatheter aortic valve implantation. A meta-analysis from 12 studies and 1,233 patients J Invasive Cardiol 2011;23:180–184.

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From Emory University Hospital, Atlanta, Georgia. The author reports no conflicts of interest regarding the content herein. Address for correspondence: Peter C. Block, MD, Emory University Hospital, 1364 Clifton Rd., F606, Atlanta, GA 30322. Email: pblock@emory.edu