Updates 6th February 2017

Hypothermia and Cardiac Arrest in Children

Outcomes after cardiac arrest remain poor in both in-hospital and out-of-hospital cardiac arrest remain poor. Targeted temperature management is recommended for comatose adults and children after out-of-hospital cardiac arrest. In a study reported by Moler et al, outcomes for children receiving therapeutic hypothermia after in-hospital cardiac arrest are reported.

In a trial conducted at 37 children’s hospitals, two temperature interventions in children who had had in-hospital cardiac arrest were compared. Within 6 hours after the return of circulation, comatose children older than 48 hours and younger than 18 years of age were randomly assigned to therapeutic hypothermia (target temperature, 33.0°C) or therapeutic normothermia (target temperature, 36.8°C).

The trial was terminated because of futility after 329 patients had undergone randomization. Among the 257 patients who had a Vineland Adaptive Behavior Scales (VABS-II score) of at least 70 before cardiac arrest and who could be evaluated, the rate of the primary efficacy outcome did not differ significantly between the hypothermia group and the normothermia group (36% [48 of 133 patients] and 39% [48 of 124 patients], respectively; relative risk, 0.92; 95% confidence interval [CI], 0.67 to 1.27; P=0.63). Among 317 patients who could be evaluated for change in neurobehavioral function, the change in VABS-II score from baseline to 12 months did not differ significantly between the groups (P=0.70). Among 327 patients who could be evaluated for 1-year survival, the rate of 1-year survival did not differ significantly between the hypothermia group and the normothermia group (49% [81 of 166 patients] and 46% [74 of 161 patients], respectively; relative risk, 1.07; 95% CI, 0.85 to 1.34; P=0.56).

The authors concluded that among comatose children who survived in-hospital cardiac arrest, therapeutic hypothermia, as compared with therapeutic normothermia, did not confer a significant benefit in survival with a favorable functional outcome at 1 year.

See: http://www.nejm.org/doi/full/10.1056/NEJMoa1610493



Coronary Flow Reserve and Clinical Outcomes in Women

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. This study by Taqueti and coworkers investigated the impact of sex, CFR, and angiographic CAD severity on adverse cardiovascular events.

Consecutive patients (n=329, 43% women) referred for invasive coronary angiography after stress testing with myocardial perfusion imaging 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.

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 (HR, 2.05; CI 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 adjusting for CFR, the effect of sex on outcomes was no longer significant.

The authors concluded that cardiovascular risk in women was independently associated with impaired CFR, representing a hidden biological risk, and a phenotype less amenable to revascularization. Impaired CFR may represent a novel target for CVD risk reduction.

See: https://doi.org/10.1161/CIRCULATIONAHA.116.023266



Breaking News:

The PCSK9 inhibitors, exert an even more powerful LDL cholesterol-lowering effect than statins, but the clinical benefit of treatment with PCSK9 inhibitors has not yet been established.

A preliminary announcement from Amgen, the manufacturer of the PCSK9 inhibitor evolocumab, has advised that the results of the first PCSK9 clinical outcomes trial (FOURIER) have met trial targets.

The FOURIER trial results will be presented at the American College of Cardiology Meeting in Washington on March 17th 2017.

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