Preoperative dipyridamole-thallium scanning predicted postoperative ischemic events, which occurred in 44.4% of patients with reversible defects versus 0% of those with no thallium redistribution.
Cohort (n=111)
Does preoperative dipyridamole-thallium scanning and clinical risk assessment predict postoperative ischemic events in patients undergoing vascular surgery?
Preoperative dipyridamole-thallium scanning effectively stratifies cardiac risk in patients undergoing vascular surgery, particularly among those with clinical risk markers.
Absolute Event Rate: 44.4% vs 0%
Dipyridamole-thallium imaging has been suggested as a method of preoperatively assessing cardiac risk in patients undergoing major surgery. To define more clearly its proper role in preoperative assessment, we prospectively evaluated 111 patients undergoing vascular surgery. In the first set of 61 patients, our data confirmed the value of preoperative dipyridamole-thallium scanning in identifying the patients who suffered postoperative ischemic events. Events occurred in eight of 18 patients with reversible defects on preoperative imaging, compared with no events in 43 patients with no thallium redistribution (confidence interval for the risk difference: 0.624, 0.256). The results also suggested that clinical factors might allow identification of a low-risk subset of patients. To test the hypothesis that patients with no evidence of congestive heart failure, angina, prior myocardial infarction, or diabetes do not require further preoperative testing, we evaluated an additional 50 patients having vascular procedures. None of the 23 without the clinical markers had untoward outcomes, while ten of 27 patients with one or more of these clinical markers suffered postoperative ischemic events (confidence interval for the risk difference: 0.592, 0.148). In the clinical high-risk subset, further risk stratification is achieved with dipyridamole-thallium scanning.
Kim A. Eagle (1987) conducted a cohort in Vascular surgery (n=111). Preoperative dipyridamole-thallium scanning (reversible defects) vs. No thallium redistribution was evaluated on Postoperative ischemic events (95% CI 0.256-0.624). Preoperative dipyridamole-thallium scanning predicted postoperative ischemic events, which occurred in 44.4% of patients with reversible defects versus 0% of those with no thallium redistribution.