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Friday, October 13th 2006

PCI v. CABG

It is difficult thing to swallow assigning procedures based on cost. The study on the cost of stenting versus coronary bypass that The Health Care Blog links to no longer works, but here’s how he quotes the abstract,

“Primary stent use cost an additional $189,000 per QALY* gained compared with a strategy that reserved stent use for treatment of suboptimal balloon angioplasty results” and they conclude that “Bypass surgery results in better outcomes than angioplasty in patients with multivessel disease, and at a lower cost”.

What is QALY?

*QALY is Quality Adjusted Life Year–a measure of life expectancy that takes into account the patient’s health, so that a year lived in good health is valued more highly than one lived with serious health conditions restricting activities of daily living or requiring significant medical care.

And Mr. Holt wonders why people “ignore” health service research, how is this any better than a for profit health care entity using overzealous utilization? Trying to determine the value of a life based on its percieved quality? Yikes!

Still, this got me looking into a larger question about the quality of percutaneous coronary intervenions versus surgery. Matthew has strong opinions that stents have worse outcomes than CABG. He links to a single study. A half hour review of the numerous (and I do mean NUMEROUS) available studies shows a prettier picture than Matt apparently holds for stents but might see his opinion out.

Early on angioplasty, PCI, and other interventional moves held for higher short term complications and mortality and in some studies higher 5 year mortality. It seems though that as the technique and devices have improved those figures have dropped. In terms of the most important quantifications (such as mortality and non-fatal attacks) I think the study’s bode out that CABG and PCI w/ stenting are pretty similiar. The number of repeat procedures that have to be done however is significantly higher in those undergoing stenting. Such a finding has been held up by numerous studies.

All these studies require subscriptions.

ERACI II (Journal of the American College of Cardiology),

At five years of follow-up, patients initially treated with PCI had similar survival and freedom from non-fatal acute myocardial infarction than those initially treated with CABG (92.8% vs. 88.4% and 97.3% vs. 94% respectively, p = 0.16). Freedom from repeat revascularization procedures (PCI/CABG) was significantly lower with PCI compared with CABG (71.5% vs. 92.4%, p = 0.0002)

ARTS Study (Journal of the American College of Cardiology),

The current observed differences in the ARTS trial for any revascularization at five years is 21.5%, for subsequent CABG is 9.3%, and for subsequent PCI is 14.9%. It is worth noting that almost 90% of patients initially treated with stenting did not require CABG over the succeeding five years. The difference in the rate of repeat revascularization between the two groups increases over time from 17.2% at 1 year to 21.5% at five years without a concomitant difference in mortality over this time period. Despite the additional risk of repeat revascularization in the stent group compared with the CABG group, this did not translate into an increase in mortality


The Stent or Surgery Trial
(The Lancet),

All patients were followed-up for a minimum of 1 year and the results are expressed for the median follow-up of 2 years. 21% (n=101) of patients in the PCI group required additional revascularisation procedures compared with 6% (n=30) in the CABG group (hazard ratio 3·85, 95% Cl 2·56–5·79, p<0·0001). The incidence of death or Q-wave myocardial infarction was similar in both groups (PCI 9% [n=46], CABG 10% [n=49]; hazard ratio 0·95, 95% Cl 0·63–1·42, p=0·80).

The use of coronary stents has reduced the need for repeat revascularisation when compared with previous studies that used balloon angioplasty, though the rate remains significantly higher than in patients managed with CABG.


Risk of Restenosis and Health Status Outcomes for Patients Undergoing Percutaneous Coronary Intervention Versus Coronary Artery Bypass Graft Surgery
(Circulation),

Angina frequency and quality-of-life scores at 1 year were compared in patients who received CABG surgery versus PCI within each stratum of preprocedural restenosis risk. Overall, 37.4% of the patients were classified as being at low risk, 46.7% at intermediate risk, and 16.1% at high risk for restenosis. Among those at low risk for restenosis, no significant differences in 1-year angina frequency (96.5±1 versus 95.5±0.5, P=0.38) or quality-of-life (91.3±1.1 versus 90.3±0.7, P=0.40) scores were found between those treated with CABG surgery and those treated with PCI. Among patients in the intermediate restenosis risk group, however, greater angina relief was achieved for those patients undergoing CABG surgery compared with those treated with PCI (96.5±1.1 versus 90.3±0.8, P<0.001). One-year quality of life was also better among intermediate-risk patients treated with CABG surgery (90.7±1.1 versus 84.9±0.8, P<0.001). Finally, in the group at highest risk for restenosis, both angina relief (92.8±3.3 versus 84.6±1.8, P=0.03) and quality of life (87.8±3.1 versus 77.9±1.7, P=0.006) were significantly better after CABG surgery as opposed to PCI.

My personal favorite for the acronym they built the title around,

The AWESOME Study (Journal of the American College of Cardiology),

A total of 232 patients was randomized to CABG and 222 to PCI. The 30-day survivals for CABG and PCI were 95% and 97%, respectively. Survival rates for CABG and PCI were 90% versus 94% at six months and 79% versus 80% at 36 months (log-rank test, p = 0.46).

Percutaneous coronary intervention is an alternative to CABG for patients with medically refractory myocardial ischemia and a high risk of adverse outcomes with CABG.

Reading these studies I’m a little surprised considering all the buzz surrounding stenting and interventional procedures. I really wanted my reading to show otherwise considering my institution’s history with the development of commercially viable stents. That however, surprisingly, hasn’t dampened my optimism. Such leads to my major criticism of The Health Care Blog’s contentions. He criticizes the cost of drug coated stents and all the hype over interventionalism when in reality it doesn’t offer major benefits over CABG (especially for multivessel disease and when patients are at increased risk of restenosis of the artery) and certainly appears to cost MORE.

However, the stent figures from these studies are significantly better than when the interventional options consisted ONLY of balloon angioplasty.

Indeed a quick glance at the SIRIUS Study (The New England Journal of Medicine) and other studies of drug coated stents appears to show major improvements over bare metal stents. Considering that restenosis is one of, if not the major risk factor seperating CABG outcomes from stent, drug stents appear to be a major step in the right direction. From SIRIUS,

There was a lower rate of out-of-hospital adverse events during the 270 days of follow-up in the sirolimus-stent group than in the standard-stent group; reductions included those in the number of patients with non–Q-wave myocardial infarction (from 7 to 1, P=0.04), the number requiring revascularization of the target lesion (from 87 to 21, P<0.001), and the number with any major adverse event (from 93 to 26, P<0.001). Similarly, the number of patients reaching the primary clinical end point, failure of the target vessel within 270 days, was reduced by 58 percent with sirolimus stents (from 110 to 46, P<0.001). The rate of survival free of target-vessel failure for 270 days increased from 78.6 percent with a standard stent to 91.1 percent with a sirolimus stent (P<0.001)

True, even if drug coated stents can eventually close the risk of having to have a repeat revasculatization procedure, their cost will still keep their value down compared to CABG.

But, interventional attempts to treat coronary artery disease are significantly younger than open heart surgery’s. The cost of these will decrease over time, and their “convience” compared to CABG will make them popular if their outcomes can come in line (which is already well on its wayt o happening) and when the cost finally start to come down.

Even dismissing the above reasons to be optimistic, which I’m sure there are very persuasive arguments which can, there is reason to be hopeful about future developments and innovations in interventional procedures. Certainly the field and efforts have come a long way fairly quickly. There is no reason not to hope or imagine that new innovations may eventually (and I mean relatively soon) allow interventional procedures to be the UNDISPUTED treatment for coronary artery disease. I have no idea what is on the horizon for the field; I make my comment only based on the recent history and the rapid rise of interventional cardiologists.

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