News in brief: LDL targets not met despite access to PSCK9i; Testosterone boost might reduce MACE in older women; ‘Natural’ pacemaker offers irregular alternative to metronomic rhythm 

Thursday, 10 Feb 2022

LDL targets not met despite access to PSCK9i

PSCK9 inhibitors are probably underutilised in patients with atherosclerotic cardiovascular disease (ASCVD) due to the complex criteria for PBS subsidy, an Australian study shows.

The hurdles include a recent lipid profile, the use of statin and ezetimibe combination for at least three months prior, and the less intensive LDL-C targets used locally compared to international guidelines.

A study of 331 undergoing PCI or CABG surgery over three months in 2020 found prescription of non-statin lipid lowering therapy remained low from admission through to discharge.

Only one patient presented on a PCSK9 inhibitor for familial hyperlipidaemia and none were eligible or initiated onto one.

“We found the barriers to prescribing PSCK9 inhibitor therapy were suboptimal rates of lipid profile measurement and the under prescribing of ezetimibe in this very high-risk group. This was despite many patients not achieving LDL-C targets and who were expected to benefit from further intensive LDL-C-lowering.”

Read more in the Internal Medicine Journal

Testosterone boost might reduce MACE in older women

Blood concentrations of testosterone and dehydroepiandrosterone (DHEA) above the lowest quartile in older women are associated with a reduced risk of a first-ever MACE.

A sub-study of the longitudinal ASPREE trial, comprising 5,535 women with a mean age of 74 years, found 2.6% had a first-ever MACE over a median of 4.4 years follow-up.

Women with testosterone concentrations in the lowest quartile had the highest risk of events (HR 0·53, 95% CI 0·34–0·82; p=0·005 at year 3) as did women in the lowest quartile of DHEA ((0·52, 0·33–0·81; p=0·004). There was no observed association between sex hormone binding globulin (SHBG) concentration and MACE.

“The associations between MACE and serum concentrations of testosterone and DHEA were independent of known risk factors for cardiovascular disease, suggesting that the effects of high concentrations of these sex steroids on MACE risk is mediated through other pathways,” the study said.

Senior investigator on the study Professor Susan Davis, from Monash University, said in a statement that we need to stop thinking about testosterone as a ‘male’ hormone that is bad for women.

“It is an important human hormone for both women and men. Further research is needed to better understand testosterone action in blood vessels and the heart, including whether treating postmenopausal women with low testosterone protects against cardiovascular disease.”

Read more in The Lancet Healthy Longevity

‘Natural’ pacemaker offers irregular alternative to metronomic rhythm

A novel bionic pacemaker which restores natural respiratory sinus arrhythmia (RSA) rather than settling for ‘metronomic’ pacing is set to be trialed in New Zealand.

The human trial follows a study in a large animal model of heart failure and earlier, in small animals, which found RSA pacing using a biofeedback device improves cardiac output by 20% and reverse-remodels the heart.

The study found animals with RSA pacing had increased cardiac output compared to monotonic pacing and non-paced time controls. A peak effect was reached after five days and maintained over four weeks of pacing.

“The increase in cardiac output was not immediate suggesting that this was not a direct haemodynamic effect,” the study said.

“Similarly, switching off the pacemaker did not result in an abrupt reduction in cardiac output back to baseline; rather this reduced slowly over a week to its pre-RSA pacing level. This result indicates that the effect of RSA pacing can persist for several days without RSA being present.”

The trial will be led by cardiologist Dr Martin Stiles from Waikato Hospital in Hamilton.

Read more in Basic Research in Cardiology

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