In March, the annual American College of Cardiology (ACC) Scientific Session showcased research that captured many facets of cardiology, raising new questions, providing positive results, and putting some once-promising ideas to rest. This also marked the first year that the ACC partnered with CRF to host the i2 Summit, with continued focus on developments in interventional cardiology.
As usual, much of the excitement hinged on late breaking clinical trial sessions.
Fresh Updates on Major Trials
An analysis of the SYNTAX trial looked at both the quality of life and costs associated with angioplasty vs. bypass surgery in patients with complex coronary artery disease. The findings suggested that dividing patients according to their level of risk—using the SYNTAX score—may help pinpoint the more costeffective strategy on an individual basis.
At 12 months, patients with triple-vessel or left main coronary artery disease who underwent surgery or received paclitaxel-eluting stents can expect a similar quality of life, with surgery having a slight edge by relieving more chest pain. Also at 12 months, the total expenses for patients treated surgically remained significantly higher than for patients treated with stents, although the gap had narrowed.
In another late breaking session, CRF faculty member George D. Dangas, MD, PhD, presented the most recent data from HORIZONS AMI, which randomized heart attack patients to anticoagulation treatment with heparin plus a glycoprotein IIb/IIIa inhibitor (GPI) or bivalirudin alone (see story, page 1).
Lessons for Clinical Practice
Several other trials presented at ACC/i2 featured data that could influence how doctors practice medicine.
In the largest real-world study of its kind, researchers analyzed data from the ACC-NCDR CathPCI Registry of over 260,000 Medicare patients, demonstrating that drug-eluting stents reduce death and heart attack rates with no increased risk of stroke or major bleeding compared with bare-metal stents in elderly patients.
Two trials, EARLY ACS and AGIR-2, compared the effects of giving GPIs earlier vs. later. EARLY ACS showed that in high-risk patients with heart attacks or chest pain early, routine use of the drug eptifibatide before angioplasty does not improve outcomes compared to delayed use after angiography. In fact, early use increases the risk of non-lifethreatening bleeding. Similarly, AGIR-2 found that patients experiencing a severe type of heart attack called ST-elevation myocardial infarction (STEMI) have equal outcomes after receiving high-dose tirofiban, regardless of whether the drug is given in the ambulance or in the catheterization lab at the time of angioplasty.
Yet ON-TIME-2 confirmed that this class of drugs still has an important role. The trial’s findings indicated that, compared to placebo, tirofiban appears to impart long-term benefits when given during ambulance transfer before hospitalization for severe heart attack. The trial showed that early use of the drug may be associated with fewer deaths.
Other studies found that the lipid-lowering drug atorvastatin could help both patients who have never taken statins and those already on regular statin therapy.
NAPLES-II demonstrated that, in patients who are not taking statin drugs, a high dose of atorvastatin in the 24 hours before elective angioplasty can reduce the chances of having a less severe form of heart attack called non-Q-wave myocardial infarction during the procedure.
But how to treat the many patients—perhaps the majority—who are already on statins? ARMYDARECAPTURE found that even these patients can benefit from atorvastatin pretreatment. The study showed that boosts of atorvastatin can be given to patients on prior statin regimens just before they receive angioplasty for stable chest pain or less severe heart attacks. This treatment resulted in better clinical outcomes at 30 days.
Another pair of studies investigated whether cardioprotection strategies could successfully limit the damage to the heart that can occur during angioplasty in patients with severe heart attacks.
One of those randomized trials involved severe heart attack patients who were being transferred via ambulance to receive emergency angioplasty. Patients in the treatment group had a blood pressure cuff repeatedly inflated and deflated on the upper arm in five-minute intervals for a total of four times. The other trial employed a similar technique further downstream: in the catheterization lab immediately after blood flow was restored to a blocked coronary artery, researchers inflated a low-pressure angioplasty balloon four times at 30-second intervals inside the artery to block the vessel.
In both studies, these methods were associated with significant decreases in the amount of heart muscle that was damaged. The effect was particularly pronounced for patients who had disease in the left anterior descending coronary artery.
Treatments Moving in the Right Direction
Another trial, ZEST, compared three different types of drug-eluting stents. At one year, a newer zotarolimus-eluting stent proved equal to a sirolimuseluting stent in the occurrence of deaths, heart attacks, and need for retreatment. Moreover, the zotarolimus-eluting stent did significantly better than a paclitaxel-eluting stent.
In addition, the VELETI trial suggested that angioplasty with drug-eluting stents may help prevent the rapid progression of coronary disease that afflicts patients who have undergone bypass surgery with vein grafts taken from elsewhere in the body. The Canadian trial found that treating moderate, non-significant blockages in these grafts with paclitaxel-eluting stents is more effective than drug therapy alone.
The PROTECT-AF trial found that permanently implanting a device in the heart’s left atrial appendage in patients with a type of irregular heart beat called atrial fibrillation protects against stroke. The treatment produces results comparable to longterm warfarin therapy and also significantly lowers the risk of hemorrhagic stroke.
And ACT-34 CMI showed that stem cells drawn from a patient’s own blood can safely treat chest pain that has resisted other therapies. The stem cells were injected into the heart muscle of patients who were ineligible for surgery or angioplasty. Early results showed improvements in chest pain and exercise time, as well as hints that major cardiovascular complications may decrease with the therapy.
Negative Trials Deal Setbacks
An innovative technology known as the Genous stent (OrbusNeich, Hong Kong, China) suffered a setback when six-month results from the GENIUS-STEMI trial revealed that heart attack patients treated with the investigational device had higher rates of complications and greater need for retreatment than similar patients treated with bare-metal stents.
The ABOARD study revealed that, for patients experiencing unstable chest pain and less severe heart attacks, performing angioplasty on the same day as when symptoms appear shortens hospital stay. However, the same-day approach does not lower the risk of heart attack or other complications compared with a strategy of next-day treatment.
In addition, results from the REVIVAL-3 trial showed that therapy with erythropoietin, a hormone that controls red blood cell production, does not improve the function of the heart’s left ventricle or reduce the amount of oxygen-deprived muscle in severe heart attack patients being treated with angioplasty.
