Perfusion tomographic scintigraphy and coronary angiography as complementary studies for the therapy decision for patients with ischemic cardiopathy

BACKGROUND: The aim of the present study was to assess the value of tomographic perfusion scintigraphy as a complement to coronary arteriography in the therapeutic management of patients admitted to the hospital for treatment of unstable ischaemic heart disease. METHODS: A review was carried out of the discharge report of 100 consecutive patients (mean age 58 years, 19 females) in which there was a mention of having taken a therapeutic decision on the basis of coronary angiography and tomographic perfusion scintigraphy with 99m-technetium isonitriles under exercise and/or dipyridamole. In 90% of instances the study was performed during drug therapy after the patient had remained stable for at least 3 days. The indication of the studies and the type of therapy was made by the attending physician. Concordance between both studies was said to exist when both pointed to the same type of therapeutic approach, either medical treatment (nonsevere stenosis on coronary arteriography with mild ischaemia on scintigraphy) or revascularization (severe stenosis with moderate or severe ischaemia in tomographic scintigraphy). Discordance was said to be present when ischaemia was mild with severe stenosis on coronary angiography. RESULTS: In 80 patients there was concordance between both studies regarding the subsequent therapeutic approach (medical treatment in 32 and revascularization in 48 [25 coronary angioplasty and 23 bypass surgery]). In the patients with discordance (n:20) medical treatment was decided in 14 patients on the basis of mild ischaemia with significant angiographic stenosis, and in only 6 patients revascularization (angioplasty in 5 and bypass surgery in 1) was indicated, based on the severity of coronary stenosis even if the ischaemia apparent on the scintigraphy was mild. CONCLUSIONS: Therefore, in 80% of patients admitted for unstable coronary artery disease there was a concordance between the results of tomographic scintigraphy and coronary angiography, when both studies were indicated to select the most appropriate therapeutic modality. In the 20% of discordant cases the attending physician decided on a conservative strategy in most cases, as no significant enough perfusion defect was shown on scintigraphy in spite of severe coronary artery stenosis.