About 75,000 people per year suffer a sudden cardiac arrest outside of hospitals in Germany. Almost half of them result from a heart attack; other causes are primary cardiac arrhythmias, cerebral haemorrhages, pulmonary embolisms or trauma. Fifteen to twenty per cent of those affected can be resuscitated with cardiac massage and electric shocks.
Some resuscitated patients have clear signs of a heart attack in the ECG, the so-called ST elevations. These patients are examined immediately after arrival at the hospital by cardiac catheterisation, allowing narrowed coronary vessels to be made visible and dilated. For all others who come to the hospital, the cause often remains unclear at first. In addition, patients themselves cannot give any information about symptoms before or after the arrest because they are unconscious in most cases.
Cardiac causes most likely for cardiac arrest
"Cardiac causes are most likely for cardiac arrest, so it was obvious to immediately catheterise everyone of whom we do not know what they have," says Prof. Steffen Desch from the University Heart Centre Lübeck, who led the study funded by the German Centre for Cardiovascular Research (DZHK). Until now, medical experts have not agreed on whether this is best for this group of patients.
The argument favouring an immediate cardiac catheterisation is that the heart suffers minor damage if blocked vessels are opened early. However, of course, only if there is a heart attack. If there is none, the patient is unnecessarily exposed to the risks of such an examination, and other diagnostic measures may come too late.
The TOMAHAWK-DZHK4 study wanted to provide more clarity here. It, therefore, investigated whether the 30-day survival rate of resuscitated patients with an unclear cause of cardiac arrest differs depending on whether they received early or delayed coronary angiography or even no coronary angiography.
The result surprised Desch and his team, even though the COACT study of 2019 already indicated this: " We found hardly any differences between the two approaches; it is more likely that the early examination is disadvantageous," Desch summarises.
The researchers analysed the data from 530 patients who had been randomly divided into two groups. The patients in the immediate group were examined by coronary angiography about three hours after they arrived at the hospital. 143 of them had died after 30 days.
The other group received intensive medical care for an average of two days before a cardiac catheterisation was performed. If other causes of the cardiac arrest were identified in the meantime, the treatment team also dispensed with coronary angiography altogether. In this delayed group, 122 people died within the first 30 days. Severe neurological damage was even slightly more common in the immediate group.
So what does this mean for the emergency in the hospital? Prof. Desch recommends to his colleagues: "In the majority of patients, there is no reason to perform hasty coronary angiographies, especially in stressful situations such as night services. Take time and follow the clinical course. If after one to two days no other causes for the cardiovascular arrest have been found, cardiac catheterisation can bring clarity."
ESC Congress 2021, 29. August 2021, 2:00pm - 2:30pm
Hot Line - TOMAHAWK | Steffen Desch
Angiography after Out-of-Hospital Cardiac Arrest without ST-Segment Elevation, Desch et al., New England Journal of Medicine, 29 August 2021 https://www.nejm.org/doi/full/10.1056/NEJMoa2101909
Study: Immediate unselected coronary angiography versus delayed triage in survivors of out-of-hospital cardiac arrest without ST-segment elevation TOMAHAWK-DZHK4
Prof. Steffen Desch, Universitäres Herzzentrum Lübeck & Herzzentrum Leipzig, Steffen.Desch(at)uksh.de
Christine Vollgraf, Press and Public Relations, German Centre for Cardiovascular Research (DZHK), Tel: 030 3465 529 02, presse(at)dzhk.de