Tag: blood pressure control

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Aggressive BP Control may Help Prevent Left Ventricular Conduction

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Electrical problems in the heart such as left ventricular conduction disease can often lead to serious and fatal complications. Treatment to lessen its effects involves implanting a permanent pacemaker, but there are no proven preventive strategies at present.

In a study published in JAMA Cardiology, researchers took advantage of a prospective trial in which individuals with hypertension were randomly assigned to standard and aggressive blood pressure (BP) control. They found that intensive BP control is associated with lower risk of left ventricular conduction disease, indicating left ventricular conduction disease may be preventable.

“This research was motivated by patients who came in with complete heart block where I put in a pacemaker and they asked, ‘Why did this happen to me?’” said senior author Gregory Marcus, cardiologist and UCSF professor of medicine. “The answer to this question has not been clear, so we wanted to look at the impact that blood pressure might have on the development of their conduction disease.”

The authors performed a statistical analysis of the previously completed Systolic Blood Pressure Intervention Trial (SPRINT) to determine the association between targeting intensive BP control and the risk of developing left ventricular conduction disease. Participants included in the five year long SPRINT trial were adults 50 years and older with hypertension and at least one other cardiovascular risk factor. Participants with early signs of left ventricular conduction disease, ventricular pacing or ventricular pre-excitation were excluded from the analysis.

Participants were randomly assigned to either normal blood pressure control (targeting a systolic blood pressure less than 140) or a more aggressive BP control (targeting a BP less than 120). As part of the analysis, the authors reviewed the serial ECGs that the participants received over the course of the trial and found that those randomly assigned to the more aggressive BP control experienced significantly less conduction disease on the left side of the heart.

“This analysis suggests that more aggressive BP control might be a way to prevent this sort of common disease,” said Marcus. “More broadly, the use of randomised controlled trial data provided compelling evidence that this common disease is not an immutable fate, but that the risk can be modified.”

By contrast, the researchers saw no differences in right-sided conduction disease (manifested by right bundle branch blocks). The authors considered right bundle branch blocks as a “negative control” since the right side of the heart is not directly affected by BP control and as such bundle branch blocks are not generally associated with the same severe outcomes as left bundle branch blocks.  

The authors note that SPRINT did not examine the role of anti-hypertensive drugs, suggesting further research into associations between specific medications and conduction disease rates may be warranted.

Source: University of California, San Francisco

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Intensive Blood Pressure Reduction after Ischaemic Stroke Increases Disability

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Credit: American Heart Association

The largest ever randomised controlled trial of intensive blood pressure lowering after thrombectomy in ischaemic stroke patients found that it led to deterioration in surrounding brain tissue and higher rates of disability, compared to less intensive treatment.

The results of the ENCHANTED2/MT trial were presented in a late-breaking session at the World Stroke Congress and simultaneously published in The Lancet. The trial was stopped early due to the significance of the findings.

Professor Craig Anderson, Director of Global Brain Health at The George Institute for Global Health, said the rapid emergence of this effect suggested the more aggressive approach was compromising the return of blood flow to the affected area.

“Our study provides a strong indication that this increasingly common treatment strategy should now be avoided in clinical practice,” he said.

Endovascular thrombectomy is an increasingly used non-surgical treatment for ischaemic stroke, in which x-ray guided microcatheters are inserted into the blood clot to dissolve it.

“A potential downside of this now widely used and effective treatment is that the rapid return of blood supply to an area that has been deprived of oxygen for a while can cause tissue damage known as reperfusion injury,” said Professor Anderson.

“This has resulted in a shift in medical practice towards more intensive lowering of blood pressure after clot removal to try and minimise this damage, but without evidence to support the benefits versus potential harms.”

To this end, researchers recruited 816 adults with acute ischaemic stroke who had elevated blood pressure after clot removal from 44 centres in China between July 2020 and March 2022. They had an average age of 67 and just over a third were female.

Of these, 407 were assigned to more-intensive (target < 120mmHg) and 409 to the less-intensive (target 140–180mmHg) systolic blood pressure control, with the target to be achieved within one hour of entering the study and sustained for 72 hours.

Researchers looked at how well the patients in both groups recovered according to a standard measure of disability, ranging from 0–1 for a good outcome without or with symptoms but no disability, scores of 2–5 reflecting increasing disability levels, and 6 being death.

Patients in the more-intensively treated group had significantly worse scores on the scale compared to those allocated to those treated less intensively.

Compared to the less-intensive group, they had more early brain tissue deterioration and major disability at 90 days but there were no significant differences in brain bleeds, mortality, or serious adverse events.

Patients who had their blood pressure more intensively controlled also rated their quality of life as significantly worse due to limitations on their physical abilities resulting from their stroke.

Prof Anderson said that after scouring the medical literature the research team had been unable to find strong enough evidence to recommend the ideal target for blood pressure control after blood clot removal in patients with acute ischaemic stroke.

“While our study has now shown intensive blood pressure control to a systolic target of less than 120mmHg to be harmful, the optimal level of control is yet to be defined,” he said.

Source: George Institute for Global Health