LOS ANGELES – Enlarge the field of CT angiography to include the heart in acute ischemic stroke patients; you’ll quickly identify sources of cardiogenic emboli and other problems that will otherwise be missed, according to investigators from the National University Hospital, Singapore.
It adds only a few seconds to the scan, with no extra contrast or meaningful increase in radiation. There’s no need to gate the heart with beta-blockers.
Among 20 acute ischemic stroke patients presenting within 4.5 hours of symptom onset, Dr. Leonard Yeo and his coinvestigators found one with a localized dissection in the ascending aorta, another with a ventricular thrombus, and a third with an atrial appendage blood clot. Both thrombus cases were confirmed by transesophageal echocardiography and started on anticoagulation the next day. The 2-phase, 64-slice nongated cardiac CT angiographies (CTA) were done in the same sitting as the brain CTA.
“Scans with 1-mm thick slices are best for screening for thrombus and structural abnormalities that cause embolism. Remarkably, [even without gating], the detail is excellent. There’s very little downside [to this, and] it maximizes your return on scans that are already a part of most acute stroke protocols,” said Dr. Yeo, a neurologist at the hospital.
“Since most of our patients get a CTA during acute stroke, it made sense to check the heart for embolic sources.” There isn’t any time to give a beta-blocker, so “these were nongated” scans, Dr. Yeo said during his presentation at the International Stroke Conference, sponsored by the American Heart Association.
Dr. Robert Hart
If it’s confirmed that nongated heart CTAs provide useful information, “we will probably all be doing this in the future. Everybody does CTs for the head in acute stroke, so all you do is go down a little lower” without any more contrast. “Within an hour of somebody presenting, you know what they have,” said Dr. Robert Hart, a neurology professor at McMaster University in Hamilton, Ont., and co-moderator of Dr. Yeo’s presentation.
In most places, acute ischemic stroke patients only get an ECG. Transesophageal echocardiography (TEE) is also good for checking the heart, but it usually comes later. It “excels at detecting abnormalities with medium embolic risk,” such as patent foramen ovale and septal aneurysm. “However, for these medium-risk cardiac sources of embolism, the optimal choice of therapy is not clear. Unlike high-risk sources which require anticoagulation, TEE does not provide therapeutic gains in terms of clinical decision making,” Dr. Yeo said.
Nongated cardiac CTAs during acute stroke, he added, also check chamber, valve, pericardial, and great vessel morphology, as well as abnormal chambers-vessel communications and “left ventricular aneurysms that can rupture with [tissue plasminogen activator], with catastrophic consequences.”
The mean age in the study was 64 years old, and about 60% of the subjects were men. None of the patients were dead at 3 months, and by then eight (40%) had modified Rankin Scale scores of 0-1. Patients were excluded if they had contraindications to IV contrast, or were unable to provide informed consent. CTA images were read by the treating neurologist and radiologist.
The work was funded by the Singapore Ministry of Health’s National Medical Research Council. The investigators have no relevant disclosures.