By MERRILL GOOZNER

The number of Americans with serious heart disease in need of hospital treatment is on the decline. A new study in today’s Journal of the American Medical Association shows the overall rate of coronary revascularizations — ranging from the coronary artery bypass graft (CABG) surgeries to in-and-out catheter-based procedures like angioplasties and stent insertions — fell from just under 1,500 per million adults a quarter in 2001 to less than 1,250 per million adults a quarter in 2008, a 15 percent decline.

The most intriguing finding in the data was that virtually all of the decline was in the most serious cases — those requiring CABG, which fell by about a third. The rate of percutaneous coronary interventions (where they snake a catheter through the thigh into the blood vessels feeding the heart, propping them open with either drug-eluting or bare metal stents) remained virtually unchanged.

The study authors, who hailed from the Philadelphia Veterans Affairs Medical Center, suspect the decline in CABG was driven by “a sizable shift in cardiovascular clinical practice patterns away from surgical treatment toward percutaneous coronary interventions” using catheters (so-called PCI). In other words, in recent years people with serious heart disease are more likely to be treated with the less invasive procedure.

A Few Caveats

That sound like a good thing, and less expensive, too. But the authors raise a few caveats. The results from a recent trial that compared CABG to PCI showed CABG had better outcomes in the most serious cases — people with three-vessel or left main coronary artery disease. They then cite another study showing that 40 percent of people with three-vessel disease were receiving CABG in 2005 compared to 50 percent in 2002, suggesting at least some of the shift from CABG to PCI was not evidence-based.

In addition, the decline in CABG surgeries was accompanied by an increase in the number of U.S. hospitals offering the surgery. In other words, more patients are getting the more serious operation at hospitals that have relatively low volumes. Some research has shown that hospitals with greater experience have superior outcomes, although the point is contested, usually by physicians and administrators at the hospitals with the low volumes.

The study doesn’t try to explain why the overall rate of hospital interventions for heart disease is declining, but it seems to me the answer is rather obvious. Though there is a rising tide of obesity and diabetes in America (both lead to of serious heart disease), those factors have been outweighed by the decline in smoking, closer attention to diet, and the better control of blood pressure and cholesterol levels provided by pharmaceutical interventions.

Nor does it explain why there was no drop in the PCI rate, which should have occurred in late 2007 and 2008 after the results of the COURAGE trial were released at the annual American College of Cardiology meeting showing that PCI was no better than aggressive drug therapy in treating patients with stable coronary artery disease. The pushback by interventionist cardiologists (see this Medscape Today video), whose livelihoods were threatened by the COURAGE results, would certainly have seemed to play a role there.

Still, shouldn’t the decline in the overall rate lead to lower health care costs? Not necessarily. First, the population is growing, so a 15 percent decline in the rate over 8 years probably kept the total number of operations about the same. Plus, if the prices of the drug-eluting stents, which have grabbed the lion’s share of the market in recent years, go up every year, and the prices charged by the hospitals for the operations go up every year, and the prices charged by the pharmaceutical industry go up every year, as they have; then no amount of attention to public health and prevention has the capacity to corral costs. As Princeton University health economist Uwe Reinhardt wrote many years ago in his effort to identify the chief culprit behind America’s outsized health care bill: “It’s the prices, stupid.”

Merrill Goozner has been writing about economics and health care for many years. The former chief economics correspondent for the Chicago Tribune, Merrill has written for a long list of publications including the New York Times, The American Prospect, The Washington Post and Financial Times. You can read more pieces by him at GoozNews, where this post first appeared.