Prolonging Clopidogrel Beneficial in Diabetes Patients with DES

In patients with diabetes mellitus (DM) receiving a first-generation drug-eluting stent (DES), prolonging clopidogrel treatment for more than 12 months may lower the chance of very late death or myocardial infarction, according to a new study published Aug. 31 in JACC. This benefit was not seen in patients receiving a bare metal stent (BMS) or patients without DM treated with either stent.

Researchers identified all patients who received stents at a Veteran Affairs facility between April 2002, and September 2006, and were alive 12 months after PCI. After exclusions, the final study cohort consisted of 28,849 patients. Patients with DM had a higher rate of death or MI 1 to 4 years after PCI compared to patients without DM.

Prolonged clopidogrel treatment was associated with a lower risk of death and death or MI only in patients with DM receiving DES, but not BMS. Additionally, prolonged clopidogrel treatment was not associated with repeat revascularization, stroke or severe bleeding. DM patients who did not require insulin had a significant interaction for prolonged clopidogrel treatment and stent type, with a significantly greater reduction in the risk of death and death or MI for DES compared to BMS. Similar trends were observed in patients treated with insulin.

At the time of the study, only first-generation DES was available. The authors note that “newer second-generation DES may modify the benefit of prolonged clopidogrel.”

The authors add that past studies have led to uncertainty and concern over prolonging dual-antiplatelet therapy (DAPT) in all patients. This study “provides evidence that prolonged DAPT can be tailored to specific patient and stent characteristics.”

In an accompanying editorial comment, John A. Bittl, MD, FACC, praises the findings of this study while still raising important questions regarding the outcomes, including the fact that the analysis “seems to be more complete for patient who received DAPT ≤ 12 months than those who continued for > 12 months.”

Bittl adds, “The key finding of the present study, which suggests that prolonged DAPT conferred a benefit in diabetic patients after DES implantation, is not supported by the neutral findings for death or MI in diabetic patients after [BMS] implantation despite absolute event rates that were higher than those after DES implantation. The inability to show a benefit after bare-metal stent implantation or in several [randomized controlled trials] after newer-generation DES implantation weakens support for prolonged DAPT for diabetic patients undergoing stenting in current practice and emphasizes that observational studies, like philosophy, although indispensable for interpreting contemporary events, cannot change them. Before prolonged DAPT can be routinely recommended for diabetic patients undergoing stent implantation, additional investigation is needed to define the pathogenetic links between the metabolic changes and clinical manifestations of diabetes mellitus, and dedicated clinical trials are needed to identify best practices.”

Thukkani AK, Agrawal K, Prince L, et al. J Am Coll Cardiol. 2015;66(10):1091-101.

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Novel Transcatheter Valve Shows Promise

A small study published in JACC has shown that a novel transcatheter heart valve is feasible and was associated with good outcomes and few complications.

It is known that up to one third of patients with severe mitral regurgitation (MR) requiring mitral valve repair or replacement are deemed to be at too high risk for surgery, and percutaneous mitral repair is not an option for all patients. Transcatheter mitral valve replacement (TMVR) has recently emerged as a new option for treatment. However, there is little data on the procedural results and no follow-up status has previously been reported.

In this study, three patients with severe MR were evaluated by a multidisciplinary team composed of cardiac surgeons, interventional cardiologists, echocardiographers, and radiologists. The subjects were treated with the Fortis transcatheter mitral heart valve and had a clinical visit and transaortic echocardiography examination at 1- to 3-month and 6-month follow-ups. The functional status, exercise capacity and quality of life of the patients were evaluated at baseline and follow-ups.

The valve was successfully implanted via a transapical approach without major complication in each case. Echocardiographic examinations before hospital discharge showed no MR in one patient and trivial MR in the other two. No patient presented an increase of the aortic outflow gradient after implantation.

At the 6-month follow-up, all patients had survived. One patient had been hospitalized 30 days after the procedure because of gastrointestinal bleeding which ceased after clopidogrel treatment. At the 3-month follow-up, all patients showed an improvement in NYHA functional class, DASI functional status, distance walked in the 6MWT, and quality of life. Echocardiographic examinations revealed normal prosthesis function in all patients, with a trace leak in one patient and no MR in another patient. Functional status improvement persisted at 6 months, with all patients in NYHA functional class ≤ II. Transmitral gradients remained similar to those observed post procedure and no thrombus was observed.

After 3 months, optimal valve performance was achieved in call cases. No fractures of the valve frame or erosion of the posterior aortic wall were detected. Adequate space at the level of the outflow tract was apparent in all cases.

The authors, led by Omar Abdul-Jawad Altisent, MD, note that Edwards Lifesciences temporarily halted the prospective Fortis clinical trial in May 2015 due to valve thrombus noted in some of the valves. They suggest that a strict anticoagulation regime may be needed after TMVR. They add that, while their findings are encouraging, “a close, longer-term follow-up is needed to confirm these promising early results.”

In an editorial comment accompanying the study, Howard A. Cohen, MD, FACC, and Brian P. O’Neill, MD, write that Abdul-Jawad Altisent and colleagues “are to be congratulated for their contribution to the field of TMVR in this group of high-risk patients[…] This is an exciting time in the evolutionary and revolutionary treatment of valvular heart disease, with an opportunity to improve the lives of our patients.” They add that we have learned from transcatheter aortic valve replacement that patients who were once thought to be “too sick” can be treated. They conclude that it is reasonable to consider TMVR in patients who need mitral valve replacement but who are thought to be at a high risk for surgery.

M Abdul-Jawad Altisent O, Dumont E, Dagenais F, et al. J Am Coll Cardiol. 2015;66(9):1011-9.

Keywords: CardioSource WorldNews Interventions, Diabetes Mellitus, Drug-Eluting Stents, Follow-Up Studies, Mitral Valve, Mitral Valve Insufficiency, Myocardial Infarction, Stents, Ticlopidine

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