The Prognostic Value of 99mTc-HMPAO-Labeled Leucocyte SPECT/CT in Cardiac Device-Related Infective Endocarditis.

OBJECTIVES

This was a prospective, single-center study designed to assess the prognostic value of the hybrid technique of single photon emission tomography and computed tomography with the application of technetium99m-hexamethylpropyleneamine oxime-labelled autologous leukocytes (99mTc-HMPAO-SPECT/CT) in patients with cardiac device-related infective endocarditis (CDRIE).

BACKGROUND

CDRIE entails the risk of complications and an increase in mortality rates, both in-hospital and long-term. The prognostic value of 99mTc-HMPAO-SPECT/CT in the course of CDRIE has not been evaluated so far.

METHODS

The project enrolled 103 consecutive patients with suspected CDRIE, all of whom underwent 99mTc-HMPAO-SPECT/CT. The resulting scans were then classified as positive if the presence of abnormal tracer uptake involving cardiac and intravascular sections of the device electrodes was found. Patients were prospectively observed for a mean time of 17.48 ± 11.9 months. All-cause mortality, in-hospital mortality, and complete hardware removal were assessed, followed by a composite endpoint including complications, namely embolic events, new onset heart failure, uncontrolled infection, renal replacement therapy, reoperation, new heart rhythm, and conduction disturbances.

RESULTS

In the analysis, despite a noticeable trend, all-cause mortality rates were not found to be statistically significantly higher among the 35 patients who registered positive results using 99mTc-HMPAO-SPECT/CT for CDRIE (group 1) than among the 68 patients from group 2 whose 99mTc-HMPAO-SPECT/CT results were negative (20% vs. 10.3%, respectively; p = 0.14). However, group 1 did present higher in-hospital mortality (11.4% vs. 0%, respectively; odds ratio: 19.6; 95% confidence interval [CI]: 1.02 to 374.70), an increased rate of complications (43% vs. 9%, respectively; hazard ratio [HR]: 5.9; 95% CI: 2.27 to 15.20), and underwent hardware removal more frequently (57% vs. 16%, respectively; HR: 4.3; 95% CI: 2.07 to 19.08).

CONCLUSIONS

In patients with suspected CDRIE, positive 99mTc-HMPAO-SPECT/CT results were associated with increased rates of in-hospital mortality and complications.