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Archive for February, 2017

MRI in Patients with PPM and ICD

Russo et al report on safety of conducting nonthoracic MRI in patients with non-conditional permanent pacemakers or implantable cardioverter-defibrillators. The protocol and supplement provide useful information.

Abstract

BACKGROUND

The presence of a cardiovascular implantable electronic device has long been a contraindication for the performance of magnetic resonance imaging (MRI). We established a prospective registry to determine the risks associated with MRI at a magnetic field strength of 1.5 tesla for patients who had a pacemaker or implantable cardioverter– defibrillator (ICD) that was “non–MRI-conditional” (i.e., not approved by the Food and Drug Administration for MRI scanning).

METHODS

Patients in the registry were referred for clinically indicated nonthoracic MRI at a field strength of 1.5 tesla. Devices were interrogated before and after MRI with the use of a standardized protocol and were appropriately reprogrammed before the scanning. The primary end points were death, generator or lead failure, induced arrhythmia, loss of capture, or electrical reset during the scanning. The secondary end points were changes in device settings.

RESULTS

MRI was performed in 1000 cases in which patients had a pacemaker and in 500
cases in which patients had an ICD. No deaths, lead failures, losses of capture, or ventricular arrhythmias occurred during MRI. One ICD generator could not be interrogated after MRI and required immediate replacement; the device had not been appropriately programmed per protocol before the MRI. We observed six cases of self-terminating atrial fibrillation or flutter and six cases of partial electrical reset. Changes in lead impedance, pacing threshold, battery voltage, and P-wave and R-wave amplitude exceeded prespecified thresholds in a small number of cases. Repeat MRI was not associated with an increase in adverse events.

CONCLUSIONS

In this study, device or lead failure did not occur in any patient with a non–MRIconditional pacemaker or ICD who underwent clinically indicated nonthoracic
MRI at 1.5 tesla, was appropriately screened, and had the device reprogrammed in
accordance with the prespecified protocol.

 

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ATLAS 2

The ATLAS 2 trial is available here.

Abstract

Background

Acute coronary syndromes arise from coronary atherosclerosis with superimposed
thrombosis. Since factor Xa plays a central role in thrombosis, the inhibition of factor Xa with low-dose rivaroxaban might improve cardiovascular outcomes in
patients with a recent acute coronary syndrome.

Methods

In this double-blind, placebo-controlled trial, we randomly assigned 15,526 patients with a recent acute coronary syndrome to receive twice-daily doses of either 2.5 mg or 5 mg of rivaroxaban or placebo for a mean of 13 months and up to 31 months. The primary efficacy end point was a composite of death from cardiovascular causes, myocardial infarction, or stroke.

Results

Rivaroxaban significantly reduced the primary efficacy end point, as compared with placebo, with respective rates of 8.9% and 10.7% (hazard ratio in the rivaroxaban group, 0.84; 95% confidence interval [CI], 0.74 to 0.96; P = 0.008), with significant improvement for both the twice-daily 2.5-mg dose (9.1% vs. 10.7%, P = 0.02) and the twice-daily 5-mg dose (8.8% vs. 10.7%, P = 0.03). The twice-daily 2.5-mg dose of rivaroxaban reduced the rates of death from cardiovascular causes (2.7% vs. 4.1%, P = 0.002) and from any cause (2.9% vs. 4.5%, P = 0.002), a survival benefit that was not seen with the twice-daily 5-mg dose. As compared with placebo, rivaroxaban increased the rates of major bleeding not related to coronary-artery bypass grafting (2.1% vs. 0.6%, P<0.001) and intracranial hemorrhage (0.6% vs. 0.2%, P = 0.009), without a significant increase in fatal bleeding (0.3% vs. 0.2%, P = 0.66) or other adverse events. The twice-daily 2.5-mg dose resulted in fewer fatal bleeding
events than the twice-daily 5-mg dose (0.1% vs. 0.4%, P = 0.04).

Conclusions

In patients with a recent acute coronary syndrome, rivaroxaban reduced the risk of the composite end point of death from cardiovascular causes, myocardial infarction, or stroke. Rivaroxaban increased the risk of major bleeding and intracranial hemorrhage but not the risk of fatal bleeding.

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Events Rates: Paroxysmal versus Persistent/Permanent AF. Insights from ENGAGE AF-TIMI 48

Link et al report on the relationship between types of atrial fibrillation and outcomes in the ENGAGE AF TIMI 48 trial.

Abstract

Background

Whether the pattern of atrial fibrillation (AF) modifies the risk/benefit of anticoagulation is controversial. In ENGAGE AF-TIMI 48 trial (Effective Anticoagulation with Factor Xa Next Generation in Atrial Fibrillation– Thrombolysis in Myocardial Infarction 48), the factor Xa inhibitor edoxaban was noninferior to warfarin in preventing stroke or systemic embolic events and significantly reduced bleeding and cardiovascular mortality. However, detailed
analyses by AF pattern have not been reported.

Methods and Results

The 21 105 patients were categorized as having paroxysmal (

Conclusions

In ENGAGE AF-TIMI 48 trial, patients with paroxysmal AF suffered fewer thromboembolic events and deaths compared with those with persistent and permanent AF. The efficacy and safety profile of edoxaban as compared with warfarin was consistent across the 3 patterns of AF.

 

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Coronary Flow Reserve and Cardiovascular Outcomes in Patients with Non-obstructive CAD: Women versus Men

Taqueti et al report a prospective study of consecutive patients undergoing invasive angiography for assessment of chest pain and used positron emission tomography (PET) determined coronary flow reserve to explore the relationship between angiographic findings, CFR and cardiovascular outcomes.

Abstract

BACKGROUND:

Cardiovascular disease (CVD) fatality rates are higher for women than for men, yet obstructive coronary artery disease (CAD) is less prevalent in women. Coronary flow reserve (CFR), an integrated measure of large- and small-vessel CAD and myocardial ischemia, identifies patients at risk for CVD death, but is not routinely measured in clinical practice. We sought to investigate the impact of sex, CFR, and angiographic CAD severity on adverse cardiovascular events.

METHODS:

Consecutive patients (n=329, 43% women) referred for invasive coronary angiography after stress testing with myocardial perfusion positron emission tomography and with left ventricular ejection fraction >40% were followed (median, 3.0 years) for a composite end point of major adverse cardiovascular events, including cardiovascular death and hospitalization for nonfatal myocardial infarction or heart failure. The extent and severity of angiographic CAD were estimated by using the CAD prognostic index, and CFR was quantified by using positron emission tomography.

RESULTS:

Although women in comparison with men had lower pretest clinical scores, rates of prior myocardial infarction, and burden of angiographic CAD (P<0.001), they demonstrated greater risk of CVD events, even after adjustment for traditional risk factors, imaging findings, and early revascularization (adjusted hazard ratio, 2.05; 95% confidence interval, 1.05–4.02; P=0.03). Impaired CFR was similarly present among women and men, but in patients with low CFR (<1.6, n=163), women showed a higher frequency of nonobstructive CAD, whereas men showed a higher frequency of severely obstructive CAD (P=0.002). After also
adjusting for CFR, the effect of sex on outcomes was no longer significant.
When stratified by sex and CFR, only women with severely impaired CFR demonstrated significantly increased adjusted risk of CVD events (P<0.0001, P for interaction=0.04).

CONCLUSIONS:

Women referred for coronary angiography had a significantly lower burden of obstructive CAD in comparison with men but were not protected from CVD events. Excess cardiovascular risk in women was independently associated with impaired CFR, representing a hidden biological risk, and a phenotype less amenable to revascularization. Impaired CFR, particularly absent severely obstructive CAD, may represent a novel target for CVD risk reduction.

 

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