The annual Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium is the world's preeminent forum for interventional cardiologists, cardiac surgeons, and vascular medicine specialists. Attendees gather to hear the latest data from key clinical trials and to observe live cases focusing on coronary artery disease, peripheral vascular disease, and structural heart disease. At the 23rd annual TCT conference, held in San Francisco, November 7-11, 2011, numerous practice-changing results were presented across a broad range of cardiovascular topics.
Catheter-Based Valve Therapy
PARTNER at 2 Years
The groundbreaking results at one year from the PARTNER (Placement of Aortic Transcatheter Valves) trial were maintained at two years, continuing to support the superiority of catheter-based heart valve replacement over standard therapy for patients with severe aortic disease who are not candidates for surgery.
PARTNER randomly assigned over 350 inoperable patients with severe aortic disease and heart-related symptoms to catheter-based valve replacement or standard therapy, which consisted of drug management, conservative care, and/or balloon angioplasty inside the aortic valve.
At two years, overall rates of heart-related death, repeat hospitalization, and severe heart failure symptoms were all lower with catheter-based valve replacement, while stroke rates were higher. According to the researchers, these findings continue to support the role of catheter-based valve replacement as the standard-of-care for patients with severe aortic disease who are not
surgical candidates.
PARTNER Quality of Life/Cost-Effectiveness
Additional data from a portion of the PARTNER trial that looked at high-risk patients with severe aortic disease showed that catheter-based aortic valve replacement was less invasive and no worse than surgical valve replacement in this patient subgroup.
Specifically, when the catheter-based approach was used to perform the procedure via an artery in the thigh, there was a significant increase in quality of life at one month, although at six and 12 months the difference decreased and was the same as surgery. Both surgical and catheter-based aortic valve replacement resulted in substantial improvement in quality of life over one year of follow-up.
Another study performed in the same group of patients investigated 12-month cost-effectiveness of catheter-based valve replacement compared with the surgical method. In terms of resource use, the catheter-based method when performed via an artery in the thigh shortened hospital length of stay by about six days compared with surgery.
Meanwhile, major blood vessel-related complications were higher with the catheter-based method compared with surgery while major bleeding was lower. The costs of the first hospital admission and those that accumulated during the year after treatment were equivalent between the two techniques; however, the catheter-based method performed via an artery in the thigh showed slightly fewer complications at less cost over one year than surgical aortic valve replacement, and was thus declared “economically dominant.”
STACCATO
In the STACCATO trial, researchers focused on a comparison between elderly surgical candidates with aortic disease who were randomly assigned to catheter-based valve replacement via an incision in the ribs or surgical replacement. Despite a planned enrollment of 200, the trial was stopped early after only 70 patients were signed up due to an excess number of complications in the group treated via catheter.
Questions were raised, however, about whether the results reflected poorly on the catheter approach. Because only a relatively small number of patients enrolled, for example, the excess complications in the catheter-based arm may have been due to chance. In addition, only one valve size was available during the trial enrollment period. The results with the catheter-based method performed via an incision in the ribs from this small trial also may not have been representative of those currently being achieved at experienced centers.
Primary Angioplasty in Severe Heart Attack
RIFLE STEACS
The RIFLE STEACS trial randomly assigned 1,001 patients with severe heart attack to stent implantation via an artery in the wrist or the groin.
When considered together, heart-related deaths, heart attacks, repeat procedures, strokes, and bleeding unrelated to bypass surgery were lower with the wrist-based stenting technique. Looking at outcomes individually, heart related death was less common with wrist-based stenting, but there was no difference between the two groups in heart attacks, repeat procedures, or strokes.
Based on the results, researchers concluded that the wrist-based approach should no longer be considered just an alternative to groin-based stenting but should be recommended for severe heart attack patients.
MUSTELA
For the MUSTELA trial, investigators presented data on over 200 patients with severe heart attack and large clots randomly assigned to stenting with or without thrombus aspiration, a technique that sucks pieces of clot out of arteries.
At one hour, key electrical activity in the heart had normalized in over half of the aspiration patients, but only about a third of the patients who did not receive clot aspiration. However, three months after the heart attack, the amount of heart muscle damage was equal in both groups, and at one year, complications were equally low with or without the aspiration technique.
The data provided a mixed picture regarding the worth of clot aspiration in addition to stenting.
DEB-AMI
Drug-coated angioplasty balloons, which reduce the amount of time patients are exposed to drugs compared with drug-releasing stents, have been touted as a way to lower the chances of a dangerous blood clot forming after treatment. But according to the DEB-AMI trial, emergency use of these balloons in people having heart attacks is not as effective at keeping treated vessels open at six months as standard metal or drug-releasing stents. There is, however, no difference between the three therapies in major complications.
Drug Therapy and Risk After Angioplasty
ADAPT-DES
According to another study, the level of effectiveness of therapy that combines aspirin with the blood-thinning agent clopidogrel can predict dangerous and potentially fatal blood clots. The findings presented by CRF faculty member Gregg W. Stone, MD, of NewYork-Presbyterian Hospital/Columbia University Medical Center (New York, NY), provide little usefulness in individual patients now but will aid clinical trials, researchers said, especially those focusing on heart attacks or unstable chest pain.
ADAPT-DES included over 8,500 patients with stable heart disease or heart attacks/unstable chest pain who were treated with drug-releasing stents between 2008 and 2010. Patients were given aspirin and clopidogrel and tested to determine how well the combined drug therapy was working.
Clotting was observed in less than 1% of patients, but low levels of drug effectiveness were significantly associated with increased clotting.
DESERT
Results of the DESERT study showed that even seven years after patients are implanted with drug-releasing stents, they are still at risk of developing dangerous and potentially fatal blood clots. The findings, which were collected from a registry of over 950 patients treated with drug-releasing stents, also revealed that patients with blood clotting more than 30 days after stent implantation had a lower risk of death than those who had blood clotting earlier.
PARIS
After patients are implanted with a stent, it is crucial that they take drugs that suppress blood platelets in order to discourage dangerous clots from forming. This regimen can last from 30 days for bare-metal stents to a year or more for drug-releasing stents. Patients who don't comply with the protective drugs, or do so intermittently, are at increased risk of a potentially fatal heart attack.
In the PARIS study, investigators led by CRF faculty member Roxana Mehran, MD, of Mount Sinai Medical Center (New York, NY), found that after 30 days, a little over 2% of patients were no longer following the prescribed regimen. More than two-thirds simply stopped the therapy, in some cases due to episodes of bleeding, while others interrupted the drugs because they were scheduled for surgery or halted therapy on their doctor's recommendation. Although such patients had higher rates of complications such as heart attacks, the numbers were too small to draw any firm conclusions about how much risk they incurred.
RAPID GENE
Other researchers found that using a specialized device to analyze a patient's genetic likelihood of responding to blood thinner agents can help physicians to individually tailor treatment after angioplasty and make treatment more effective. Saving time and energy, the genetic analysis can be done easily through a cheek swab taken by a nurse.
TRIGGER-PCI
Although stopped early for failing to show a difference that would actually affect the risk of adverse events, the TRIGGER-PCI study still linked treatment with the new blood thinning agent prasugrel after angioplasty to a better response by blood platelets compared with the older agent clopidogrel. Over 400 patients were randomly assigned to prasugrel or clopidogrel and all patients received drug-releasing stents. The study primarily looked at heart-related death and heart attack rates; overall, there was only one such occurrence—in the clopidogrel group.
BRIDGE
An additional trial looked at over 200 patients with heart attacks or unstable chest pain who had previously been implanted with a stent and had discontinued blood-thinning therapy prior to heart surgery. These patients were randomly assigned to therapy with the alternative blood-thinning agent cangrelor or placebo. Researchers found that cangrelor is safe to use in these patients, and rates of excessive bleeding were similar in both groups, with a total of 22 bleeding events observed.
Drug-Releasing Stents and Drug-Coated Balloons
EVOLVE
The EVOLVE trial tested whether a drug-releasing stent with an absorbable polymer coating on one side was as effective as a standard stent with a permanent all-over coating. The latter is thought to contribute to the risk of a serious blood clot insofar as the coating provokes inflammation and slows healing from the trauma of stenting.
Australian researchers found that the new stent—at both full and half drug doses—was as good as the one with the conventional coating at keeping vessels open at six months. Moreover, there were no differences between the devices in terms of heart-related deaths or need for repeat procedures to open the artery.
REMEDEE
The REMEDEE trial tested the safety and effectiveness of a drug-releasing stent that incorporates two strategies: a standard drug (sirolimus) that helps keep vessels open and a molecule that enhances healing around the stent. It marked the first time the stent was investigated in humans. According to the German investigators, at nine months the dual-therapy stent matched a conventional drug-releasing stent both in maintaining blood flow and in rates of major complications such as death, heart attack, and need for a repeat procedure.
NEXT
Compared with an older stent that releases the drug paclitaxel, a new stent that releases the drug sirolimus and has no polymer coating on its metal frame is more effective, according to data from the multicenter NEXT trial. Researchers randomly assigned over 300 patients to one of the two devices. The newer product utilizes technology that controls and directs drug release to the blood vessel wall along with a drug formulation that enhances overall safety and effectiveness. In the study, it proved better at reducing artery renarrowing compared with the older stent.
TWENTE
The TWENTE trial, involving over 1,300 patients with chronic stable or acute heart disease, found that a stent that releases the drug zotarolimus is no worse than an everolimus-releasing stent for both safety and effectiveness. It is only the second randomized study to compare these two stents head-to-head.
One year after patients underwent angioplasty, there was no difference between the stent groups in terms of heart attack, need for additional artery-opening heart procedures, or death due to heart disease.
PEPCAD-DES
Even coronary vessels treated in a timely fashion with drug-releasing stents can become reblocked by progressive atherosclerosis. The PEPCAD-DES trial compared treatment of these repeat offenders with a drug-releasing balloon vs. an uncoated angioplasty balloon. German researchers reported that at six months the drug-releasing balloon performed better on several measures of effectiveness. The incidence of major complications also was lower among patients who received the drug-releasing balloon, driven mainly by the reduced need for repeat procedures.
Interventional Techniques and Adjunctive Procedures
PROFI
A balloon device appears to be more effective than a filter in preventing patients from suffering a stroke during or after procedures to open blocked carotid arteries in the neck.
For the PROFI trial, investigators randomly assigned 62 patients with internal blockage of the carotid artery undergoing angioplasty to either a filter or balloon occlusion device. At 30 days, the filter group had a higher incidence of new brain lesions, which can lead to stroke.
ROTAXUS
Rotablation, a process of drilling through plaque deposits in the arteries before implanting a drug-releasing stent, offers no advantage over stenting without drilling, according to findings from the ROTAXUS trial.
ADVISE
A new drug-free method for measuring the severity of blockages in coronary arteries compares favorably to the more conventional method, which involves injection
of a drug.
For the ADVISE trial, investigators tested the drug-free measurement method, called instant wave-free ratio, and reported excellent efficiency and accuracy in diagnosing blockages.
COBRA
Cryoplasty, a process of dilating and cooling blood vessel walls, was found to result in better outcomes in patients with diabetes than standard balloon angioplasty.
In the COBRA trial, researchers studied 90 patients with diabetes as well as severe atherosclerosis of the femoral artery in the thigh due to plaque build-up.
Patients were randomly assigned to undergo cryoplasty or conventional balloon angioplasty without vessel cooling. The main difference between the techniques is that cryoplasty uses liquid nitrous oxide rather than saline to inflate the angioplasty balloon, cooling its surface temperature to approximately -10° C.
At 12 months, renarrowing of treated arteries was significantly less severe in patients who received cryoplasty compared with conventional angioplasty.
