Обзор американских кардиологических журналов за неделю (ссылки)

[Chevychelov]

FDA approves combination sitagliptin, simvastatin
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The FDA today announced approval of a fixed-dose combination therapy containing sitagliptin and simvastatin for the treatment of adults with type 2 diabetes and high cholesterol.

“This is the first product to combine a type 2 diabetes drug with a cholesterol-lowering drug in one tablet,” Mary H. Park, MD, director of the division of metabolism and endocrinology products in the FDA Center for Drug Evaluation and Research, said in a press release. “However, to ensure safe and effective use of this product, tablets containing different doses of sitagliptin and simvastatin in fixed-dose combination have been developed to meet the different needs of individual patients. Dose selection should factor in what other drugs the patient is taking.”

The combination tablet (Juvisync; Merck) was approved in sitagliptin/simvastatin dosage strengths of 100 mg/10 mg, 100 mg/20 mg and 100 mg/40 mg. According to the FDA, treatment should only be prescribed when patients require treatment with both sitagliptin (Januvia, Merck) and simvastatin (Zocor, Merck).
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MRI deemed safe for patients with selected implanted cardiac devices

Nazarian S. Ann Intern Med. 2011;155:415-424.
Reynolds MR. Ann Intern Med. 2011;155:470-472.
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MRI can be performed safely in patients with selected pacemaker and implantable cardioverter defibrillators when using device selection and programming protocol, new data suggest.

Patients with clinical indication for MRI and an implantable device were enrolled in a study between February 2003 and April 2010. Researchers enrolled 438 patients (54% had a pacemaker; 46% had ICDs) who underwent 555 MRI examinations. Most MRIs were of the brain, 22% of the spine, 16% of the heart, 13% of the abdomen or pelvis and 9% of an extremity.

Immediately after MRI, right ventricular sensing (median change, 0 mV), and atrial (median change, –2 Ù) and right (median change, –4 Ù) and left (–11 Ù) ventricular lead impedances were reduced, according to researchers. At long-term follow-up, 61% of patients had decreased right ventricular sensing (median, 0 mV), right ventricular lead impedance (median, –3 Ù), battery voltage (median, –0.01 V) and increased right ventricular capture threshold (median, 0 V).

Three patients had their device reverted to a transient backup programming mode, with no long-term effects. According to the researchers, this was the “primary clinically significant event attributable to MRI.”

They concluded that “MRI was performed safely in all patients.” However, image distortion, signal voids or bright areas, and poor fat suppression were noted when the device was located in the MRI field of view. “Given the potential for changes in device variables and programming, monitoring by device experts is necessary,” they wrote.

The researchers said patients were selected and treated based on previous safety studies. Only patients with pacemakers manufactured after 1998 and defibrillators manufactured after 2000 were enrolled, and researchers followed programming and monitoring protocol.

“The risks and benefits of MRI in a patient with a cardiac rhythm management device should be assessed on an individualized basis, as with any important medical decision,” Matthew R. Reynolds, MD, MSc, and Peter Zimetbaum, MD, of the division of cardiology, Beth Israel Deaconess Medical Center, wrote in an accompanying editorial. “The authors have not demonstrated that MRI in these patients is risk-free, only that the risks are quantitatively small. Therefore, before permitting a patient to have MRI, the potential benefits of the MRI relative to alternative diagnostic strategies should be established.
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600-mg loading dose of clopidogrel reduced infarct size in STEMI patients

Patti G. J Am Coll Cardiol. 2011;58:1592-1599.
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A reduction of infarct size and improvement of angiographic results, residual cardiac function and 30-day major adverse CV events were associated with pretreatment with a 600-mg loading dose of clopidogrel vs. a 300-mg loading dose before primary percutaneous coronary intervention in STEMI patients, according to an analysis of the ARMYDA-6 MI study.

Patients with STEMI undergoing primary PCI were enrolled in the study. Researchers randomly assigned a 600-mg or 300-mg loading dose of clopidogrel to patients before the procedure. The primary endpoint was defined as the evaluation of infarct size, and secondary endpoints were the prevalence of thrombolysis in MI flow grade of more than 1 before PCI and less than 3 after PCI; left ventricular ejection fraction by transthoracic echocardiography at discharge; incidence of major adverse CV events at 30 days; and occurrence of bleeding or entry site complications.

Overall, the primary endpoint concluded that infarct size was lower in patients assigned to the 600-mg dose. Looking at secondary endpoints, TIMI flow grade of more than 1 at diagnostic coronary angiography before PCI was found in 21.4% of patients in the 600-mg arm vs. 12.2% in the 300-mg arm, whereas a lower incidence of TIMI flow grade of less than 3 was associated with the 600-mg dose (P=.031). Study results showed that LVEF early after PCI was similar in the two arms (P=.42), but was higher in the 600-mg dose at discharge (P=.026). The 600-mg group also had a reduced incidence of 30-day major adverse CV events vs. the 300-mg group (P=.049).

Researchers also found that symptom-to-balloon (P=.86) time and clopidogrel load-to-balloon time (P=.45) were similar in the two arms.

The results are somewhat limited by a small sample, but having said that, they are significant. Furthermore while 600 mg improved non fatal outcomes, the important fact was the benefit was achieved without an increase in bleeding or other measured side effect. Furthermore, there appears to be a finite number of receptors bound by a P2Y12 inhibiter so increasing the dosage improves the possibility of achieving an important therapeutic level early while not paying a price for the higher loading dose.