August 29, 2012

Advanced scanner can spot people who need bypass surgery

Scientists have developed an ultra-fast, advanced scanner that can spot people with chest pain who need invasive procedures such as bypass surgery to restore blood flow to the heart.

The 320-detector computed tomography (CT) scanner was developed by a team of researchers including the Johns Hopkins University School of Medicine and the Instituto do Coracao in Sao Paulo, Brazil.

"The CORE 320 study is the first prospective, multicenter study to examine the diagnostic accuracy of CT for assessing blockages in blood vessels and determining which of those blockages may be preventing the heart from getting adequate blood flow," Joao A C Lima, senior author of the study, said.

"We found an excellent correlation in results when we compared the 320-detector CT testing with the traditional means of assessment using a stress test with imaging and cardiac catheterisation," Lima added.

The study involved 381 patients at 16 hospitals in eight countries.

The patients who completed the study had traditional SPECT tests and invasive angiography.

SPECT is a nuclear medicine stress test with imaging, which shows reduced blood flow to the heart without indicating the number or specific location of blockages.

They also had two types of tests with a non-invasive 320-detector CT scanner. In the first CT test, the scanner was used to see the anatomy of vessels to assess whether and where there were blockages.

That test is known as CTA, in which the "A" stands for angiography. Then, in a second CT test with the same machine, patients were given a vasodilator, a medicine that dilates blood vessels and increases blood flow to the heart in ways similar to what happens during a stress test.

The second test is called CTP, with the "P" standing for perfusion.

"We found that the 320-detector CT scanner allowed us to see the anatomy of the blockages as well as determine whether the blockages were causing a lack of perfusion to the heart. We were therefore able to correctly identify the patients who needed revascularisation within 30 days of their evaluation," lead author Carlos E Rochitte, said in a statement.

"Many patients are sent for an angioplasty when they may not need it. Our ultimate goal is to have more certainty about which patients having chest pain - without evidence of a heart attack - need an invasive procedure to open an arterial blockage," said cardiologist Richard George, co-author of the study.

"The CTP test added significant information about the patients' conditions and boosted our ability to identify those whose blockages were severe enough to reduce blood flow to the heart," George added.

The study was presented in the European Society of Cardiology Congress in Munich, Germany.