Varenicline linked to increased chance for serious CV events
Singh S. CMAJ. 2011;doi:10.1503/cmaj.110218.
The use of varenicline, a medication used for smoking cessation, was associated with an increased risk for serious adverse CV events, results from a meta-analysis suggested.
The researchers analyzed data from 14 double blind, randomized controlled trials that included 8,216 participants. The studies included smokers or users of smokeless tobacco who had reported CV events such as ischemia, arrhythmia, congestive HF, sudden death or CV-related death as serious adverse events linked with the use of the drug. The trials ranged in duration from 7 weeks to 1 year.
According to the results, the use of varenicline (Chantix, Pfizer) was associated with an increased risk for serious adverse CV events (52 of 4,908 patients) vs. placebo (27 of 3,308 patients; 1.06% vs. 0.82%; Peto OR=1.72; 95% CI, 1.09-2.71). The researchers said there were not enough patients in the analysis to allow meaningful comparisons of mortality.
“Our meta-analysis raises safety concerns about the potential for an increased risk of serious adverse CV events associated with the use of varenicline among tobacco users,” the researchers concluded. “Despite the limitations of our analysis, our findings have potential regulatory and clinical implications.”
In an addendum, the researchers said the FDA had announced the addition of a warning to the product label of varenicline regarding “the small increased risk of certain adverse CV events associated with the use of varenicline among smokers with CVD.”
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Recurrent stroke, vascular event rate on decline during past 50 years
Hong K. Circulation. 2011;123:2111-2119.
During a 50-year span, the annual event rate of strokes and major vascular events declined by roughly 1% per decade each, according to an analysis of nearly 60 secondary prevention trials.
The systematic review included only randomized controlled trials (n=59) published from 1960 to 2009 with a more than 6-month follow-up. Other inclusion factors were that most qualifying events were ischemic stroke or transient ischemic attack and intervention was a medical treatment. A total of 66,157 patients comprised the study population.
During the 50 years, annual event rates for recurrent stroke declined by 0.996% per decade (P=.001), with similar reductions also found for fatal stroke (0.282% decline per decade; P=.003). However, the greatest percent deduction was found with major vascular events, which declined by 1.331% per decade (P=.001).
The researchers then performed multiple regression analysis to determine the underlying causes of the decline in stroke and found that increasing use of antithrombotic agents and lowering systolic/diastolic BPs were the major contributors.
In the clinical perspective of the study, the researchers wrote on the influence of drug therapy, commenting that the introduction into practice of successive waves of therapies with proven efficacy in stroke prevention “has been notably successful, resulting in a substantial decline in the rate of recurrent vascular events in the control arms of secondary stroke prevention trials. Consequently, trials of new therapies are more arduous, requiring ever larger sample sizes to confirm treatment efficacy, and clinical investigators must cope with the paradox of progress.”
Other study data of interest showed that compared with the 3 decades before 1990, the past 20 years saw rises in hypertension, diabetes and hyperlipidemia, whereas smoking and transient ischemic attacks declined (P<.05 for all). – by Brian Ellis
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Therapeutic hypothermia yielded positive neurological outcomes among certain cardiac arrest patients
Mooney MR. Circulation. 2011;doi:10.1161/circulationaha.110.986257.
More than 90% of patients who had received therapeutic cooling as treatment for an out-of-hospital cardiac arrest survived with positive neurological outcomes, according to trial results.
There were 140 out-of-hospital cardiac arrest patients who participated in the trial between February 2006 and August 2009. Eligible patients had remained unresponsive after a return of spontaneous circulation. These patients were cooled and re-warmed with an automated, non-invasive cooling device.
Three-quarters of the patients (n=107) — including those with non-ventricular fibrillation arrest or cardiogenic shock — were transferred to a therapeutic hypothermia-capable hospital via referral from other hospitals within the participating network. Sixty-eight patients with concurrent STEMI received cardiac intervention and cooling simultaneously.
The overall survival to discharge rate was 56%. Ninety-two percent of survivors had a positive neurological outcome at discharge.
No differences in survival rates were observed between transferred and non-transferred patients. Non-ventricular fibrillation arrest and presence of cardiogenic shock were strongly linked to death. However, survivors with non-ventricular fibrillation arrest had a 100% positive neurological recovery rate, and survivors with cardiogenic shock present had an 89% positive neurological recovery rate.
For each hour of delay in initiating cooling, mortality risk increased 20% (95% CI, 4-39).
The endpoint of positive neurological outcome was defined as cerebral performance category 1 or 2 at discharge.
The researchers said therapeutic hypothermia is an underused treatment strategy despite showing signs that it improves survival and confers neuroprotection on patients who have a cardiac arrest outside of the hospital, and regional systems of care for these patients are necessary. A comprehensive protocol may result in further dispersion of this “essential therapy for [out-of-hospital cardiac arrest].”
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CAD affecting atrial branches predictive of AF development after MI
Alasady M. Heart Rhythm. 2011;8:955-960.
In a population of patients with acute MI, coronary artery disease was shown to be an independent determinant of atrial fibrillation after MI.
After examining patients (n=2,460) admitted to a cardiac care unit for MI between 2004 and 2009 and excluding patients with prior AF, pericarditis, severe valvular heart disease, left ventricular hypertrophy, LV dysfunction and recent CABG, the researchers ended up with a study population of 42 AF cases and 42 MI but no AF cases (control).
Overall, AF patients had a higher likelihood of presenting with an inferior MI (P=.002), but a lower likelihood of presenting with STEMI (P=.03) and undergoing early revascularization with primary angioplasty within 6 hours (P=.004).
Researchers also found the following variables associated with AF: indexed left atrial volume (P<.001), right atrial branch disease (P<.001), sinoatrial branch disease (P<.001), LV filling pressure (P=.001), time from onset of symptoms to coronary intervention (P=.002), left atrial branch disease (P=.009) and left main stem disease (P=.02). After multivariable analysis, they determined that both right and left coronary artery arterial branch disease predicted AF after MI (P=.02).
“With the angiographic data and echocardiographic findings, our results provide novel insight into the mechanisms underlying the development of AF in patients after they experience a heart attack,” study researcher Prashanthan Sanders, MBBS, PhD, of the Royal Adelaide Hospital, Australia, said in a press release. “The findings shed new light on how coronary disease affects the atrial branches after the trauma of a heart attack regardless of measurable effects such as a patient’s gender or age.”