In patients with a normal myocardial perfusion scintigraphy coronary revascularization deteriorates the prognosis

Objectives A normal myocardial perfusion scintigraphy (MPS) has repeatedly been shown in the US and some European countries to imply a risk of future cardiac events of <1-2% per year for most patient categories. We wanted to investigate whether this holds true for Danish patients as well. In addition, since in Denmark the result of MPS is not consistently used, we wanted to elucidate the prognosis of patients who had undergone coronary revascularization despite a normal MPS.

Methods We conducted a review of 6 years’ MPS performed in 2158 patients referred for suspected or know angina pectoris and not included in research protocols. Of these 47% were women. Follow-up data were derived from national registers containing relevant information from a follow-up period of 1-9 years.

Results Sixty-two percent of MPS (n=1328, M:F=575:753) were normal, indicating no significant stenoses of the coronary arteries. Coronary revascularization (percutaneous coronary intervention or coronary artery bypass grafting within 180 days following MPS) was done in 2% of these, predominantly in patients with known coronary artery disease (CAD) independent on age, summed stress score, ejection fraction, or previous MI. The mean follow-up was 5.1 y. The rate of events in terms of death, myocardial infarction, or later revascularization was low in both groups (on average .03 per year) but differed significantly, as revascularization increased the risk 3.6 times, CI=[2.0;6.3], p<.001, see Figure. Sex, age, or known CAD had no influence on the frequency of cardiac events.

Conclusions The fact that a normal MPS implicates a very good prognosis has been demonstrated in several settings, but to our knowledge never in a large Scandinavian material. The finding of an extreme difference in event-free survival of patients with and without revascularization speaks very clearly against revascularization if MPS is normal