Background: Myocardial perfusion scintigraphy (MPS) is an important tool in the diagnosis of ischemic heart disease. Its other uses include prognostication, risk stratification and assessment of viability. Treadmill exercise has been used as screening tool for ischemic heart disease. Duke treadmill score (DTS) was formulated to stratify patients into low, intermediate and high risk based on the duration of exercise and the presence or absence of ECG changes and angina. This study aims to determine which of among the two modalities would be better prognostic tool.
Methods: Filipino adult patients with known or suspected CAD were included in the study. Exclusion criteria are those with recent MI, recent revascularization or those with heart failure or critical illness. The patient underwent treadmill exercise test and subsequent myocardial perfusion scintigraphy. The Duke treadmill score was obtained after exercise and the summed stress score (SSS) was obtained in the scinitgraphic images. The patients were followed for 12 months for the development of major adverse events. The ROC area of SSS and DTS were computed using STATA 13 software and compared.
Results: A total of 97 patients were included in the study. The mean age was 52 years, majority were male. Five events were noted within 11.8 months of follow-up. The SSS has a higher ROC curve (0.9707) compared to DTS (0.9033) but did not reached statistical significance (p=0.0998).
Conclusion: There is a trend favoring SSS of MPS more than the DTS as a better predictor of MACE among patients suspected or with known CAD; however no statistical significance was reached because of few outcomes due to a short length of follow-up. Worsening of the SSS or DTS was strongly correlated with the development of adverse cardiac events.