Use of positron emission tomography for prediction of perioperative and late cardiac events before vascular surgery

• Published in: The American heart journal 1995-12, Vol.130 (6), p.1196-1202
• Main Authors: Marwick, Thomas H., Shan, Kesavan, Go, Raymundo T., MacIntyre, William J., Lauer, Michael S.
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; Cardiovascular system; Dipyridamole; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Myocardial Ischemia - diagnostic imaging; Myocardial Revascularization; Postoperative Complications; Predictive Value of Tests; Radionuclide investigations; Risk Assessment; Time Factors; Tomography, Emission-Computed; Vascular Surgical Procedures
• ISSN: 0002-8703; 1097-6744
• DOI: 10.1016/0002-8703(95)90142-6

The efficacy of myocardial perfusion imaging for cardiac-risk stratification of patients undergoing vascular surgery has been disputed recently. In comparison with conventional techniques, positron emission tomography (PET) has the benefit of permitting a true resting scan, allows accurate measurement of the extent of ischemia, and is highly specific for the diagnosis of coronary disease. We therefore investigated the use of PET for risk stratification at the time of vascular surgery and subsequent follow-up in 78 patients (aged 67 ± 11 years, 52 men), selected for testing before the performance of extensive surgery or because of one or more clinical risk factors. Perfusion images were obtained by using a standard rubidium 82 protocol before and after dipyridamole-handgrip stress. With use of a quantitative color scale in a 24-segment model of the left ventricle, scans were reported as showing normal perfusion, resting defects, or stress-induced defects (deterioration >15% with stress). After exclusion of 6 patients referred for myocardial revascularization, 72 patients were followed up in the perioperative period and for 18 ± 12 months for late cardiac death, myocardial infarction, or unstable angina. Perioperative events occurred in 14 patients (5 with myocardial infarction and 9 with unstable angina), 10 of whom had ischemia at PET (sensitivity, 71%; predictive value of a positive test, 45%). Isolated resting perfusion defects were not associated with events. The presence of extensive ischemia (more than five segments) had a positive predictive value of 64%, and its absence gave a negative predictive value of 89%. Ischemia was present in 12 (p = 0.003) of 59 patients without events (specificity, 79%; predictive value of a negative test, 92%). Seven patients had late events (2 with myocardial infarction and 5 with unstable angina). Of 21 patients with either an early or a late event, 14 had a stress-induced perfusion defect (sensitivity, 67%; predictive value, 64%), whereas of 52 with no event, 8 had stress-induced defects (specificity, 84%). PET appears to be an effective technique for stratification of cardiac risk in patients undergoing vascular surgery. This technique may be a useful alternative to conventional imaging in patients with previous infarction or known resting wall-motion abnormalities, because it shows differing prognostic implications of patients with resting and stress-induced perfusion defects.