A Medical Device Daily

Removing thrombus from coronary arteries with the Export aspiration catheter from Medtronic (Minneapolis) before implanting a stent in patients suffering a specific kind of heart attack "results in excellent clinical outcomes," at one year, according to new data released at American College of Cardiology (ACC; Washington) scientific sessions in Orlando, Florida.

Findings from TAPAS-II trial suggest that thrombus aspiration is feasible and safe and has potential benefits for most patients with non-ST-segment-elevation myocardial infarction (NSTEMI) heart attacks not distinguished by particular electrocardiogram (ECG) features. For treatment purposes, heart attacks are categorized as ST-segment-elevation myocardial infarction (STEMI) or NSTEMI.

The original TAPAS trial suggests that STEMI patients who received thrombus aspiration prior to stenting had significantly improved blood flow and survival rates compared to those who received conventional treatment with stents alone. Both studies, TAPAS and TAPAS-II, were conducted at University Medical Center Groningen in the Netherlands. TAPAS and TAPAS-II are single-center studies which are suggestive of excellent patient outcomes with thrombus aspiration. Further clinical data are now necessary to confirm the potential of the Export system in a wider AMI patient population.

The new study concludes that "thrombus aspiration in most NSTEMI patients is feasible and safe, is associated with a high rate of retrieval of thrombotic material, and results in excellent clinical outcomes."

TAPAS-II studied 70 patients undergoing percutaneous coronary intervention (PCI) for NSTEMI. All patients were prospectively enrolled in the study and received thrombus aspiration with the Export. Aspiration was effective at removing thrombus in 83% of the patients. The successful reduction in thrombotic load was also associated with a marked improvement in coronary flow, the researchers reported.

Results from TAPAS and TAPAS-II are consistent with those from Medtronic's EXPORT study, a randomized controlled trial of 250 patients at 24 sites in Europe and India comparing the use of the Export with conventional PCI. As reported in October 2007, the EXPORT study demonstrated that primary aspiration with the Export followed by stenting improved myocardial reperfusion in acute myocardial infarction patients.

Medtronic also reported new research that shows cardiac resynchronization therapy (CRT) may improve clinical outcomes in asymptomatic or mildly symptomatic heart failure patients, and clinical results revealed a 62% reduction in the risk of first heart failure hospitalization or death. The 24-month findings from the REVERSE (Resynchronization Reverse Remodeling in Systolic Left Ventricular Dysfunction) trial show the potential benefits of CRT in patients with mild heart failure.

CRT is not approved for use in mildly symptomatic or asymptomatic patients who were shown to benefit from CRT in this trial.

The data show that CRT used in combination with optimal medical therapy, including beta blockers and ACE inhibitors or aldosterone receptor blockers, demonstrated a statistically significant improvement in heart failure clinical composite response, a standard measurement that includes several clinical measures of heart failure status.

The study also showed CRT leads to a reduction in heart size, as measured by cardiac ultrasound, improving its function and helping the heart pump more efficiently.

"The data demonstrate that even for patients who have mild or no heart failure symptoms, CRT may have a positive impact on clinical outcomes," said Jean-Claude Daubert, MD, FACC, Department of Cardiology, Centre Hospitalier Universitaire (Rennes, France). "Preventing the progression of heart failure with device therapy may also delay the time to first hospitalization or death, thus not only helping improve patients' lives, but ultimately reducing the economic burden of heart failure to the health system."

With 610 patients studied, REVERSE is the first large-scale, global, randomized, double-blind trial to demonstrate the benefits of CRT in mild heart failure patients or asymptomatic patients who previously had heart failure symptoms. These latest results represent findings at 24 months for the European blinded cohort of 262 patients. As previously reported, the trial trended toward, but did not meet statistical significance for its primary endpoint (percent of patients worsened at 12 months using a heart failure clinical composite score), with more patients in the trial improved with CRT. This benefit was confirmed and was statistically significant with the 24 month results.

In other news from ACC:

• Lantheus Medical Imaging (North Billerica, Massachusetts) reported the Phase I data on the safety and tolerability of BMS747158, its novel fluorine 18-labeled Positron Emission Tomography (PET) tracer for myocardial perfusion imaging in subjects under rest and stress conditions. The data indicate that BMS747158 is well-tolerated and demonstrates radiation dosimetry that is comparable to or less than that of other PET agents. The data also showed high myocardial uptake at rest that significantly increases with pharmacologically induced stress and a ratio of myocardial to background radioactivity that is favorable and improved over time. These findings suggest that BMS747158 has strong potential as a myocardial perfusion PET imaging agent for patients both at rest and under stress.

"These data raise hope that BMS747158 could help address the need for a radiopharmaceutical that provides greater accuracy and broadens the applicability of PET technology for myocardial perfusion imaging," said Jamshid Maddahi, MD, professor of molecular and medical pharmacology (Nuclear Medicine) and medicine (Cardiology) at the David Geffen School of Medicine at UCLA and principal investigator of the study. "These studies found that the mean effective dose of BMS747158 was very similar to that of a commonly used F-18 labeled agent, FDG, but the radiation level absorbed by the organ receiving the highest dose was significantly lower with BMS 747158."

Preliminary results of these Phase I studies show that no adverse events attributed to BMS747158 were reported.

"These studies found that BMS747158 has high myocardial uptake among patients at rest and under stress, which points to its potential in PET myocardial perfusion PET imaging. Combined with the findings that BMS747158 is well-tolerated in the studied population, these are very encouraging data that we will aim to replicate in additional broader studies," said D. Scott Edwards, PhD, vice president, Global R&D, at Lantheus.

BMS747158 is a fluorine 18-labeled agent that binds to the mitochondrial complex 1 (MC-1) inhibitor and was designed to be a novel myocardial perfusion PET imaging agent. The compound is currently in phase 2 development.

• Improving upon the success of its current X-ray technologies, Toshiba America Medical Systems (TAMS; Tustin, California) said it is introducing a new addition to its Infini-i cardiovascular system offering the Infinix VF-i with mid-sized flat panel detector (FPD) and Next Generation AIP technology at the meeting.

The system includes a new 12"x12" flat panel detector (FPD) and a new digital processor. This system will incorporate all the technology that the Infinix line provides for unprecedented access, including complete head-to-toe and fingertip-to-fingertip coverage, and comprehensive system configuration.

TAMS also said it showcased the company's newest additions to the Aplio Artida ultrasound system. It said it also introduced a pediatric package and two new probes, significantly expanding the clinical utility of Artida.

Toshiba highlighted two new software upgrades that will improve its proprietary 3-D and 2-D wall motion tracking.

In addition to the 3-D and 2-D wall motion tracking upgrades, TAMS is expanding the clinical applications for ultrasound in pediatric care with new a pediatric package and two new probes. The new pediatric probes will provide higher transducer frequencies for pediatrics, resulting in the highest levels of image quality, the company said.