Diagnostic accuracy of 64-slice multidetector computed tomography in evaluation of post-coronary artery bypass grafts in correlation with invasive coronary angiography

Role of MDCT in Assessment of Long-term Graft Patency in Female Patients

Objectives:

The aim of the study was to analyze the utility of CT-coronary angiogram (CT-CAG) in assessment of long-term graft patency compared to conventional invasive coronary angiography (ICA) and highlight any gender-specific issues in female post-coronary artery bypass surgery (CABG) patients.

Materials and Methods:

The medical records and images of 30 patients including four female patients who had CABG in the past and underwent both conventional and CT-CAGs were analyzed retrospectively.

Results:

We studied 30 patients who had CABG in whom both CT-CAG and conventional coronary angiograms were performed. CT-CAG was able to evaluate the grafts better than ICA and was useful even in those which could not be assessed due to technical failure by ICA. There were only four female patients in this series. In first patient, the arterial graft (left internal mammary artery [LIMA]) was patent but distal run off was absent in LAD in CT-CAG images and was reported as poor in conventional coronary angiogram. The second patient had CABG 10 years back. The arterial graft (LIMA) to LAD was patent and there was total block in SVG graft to RCA at proximal anastomotic site. The third patient with hypertension and diabetes also had CABG 10 years back. Both LIMA to LAD and SVG to PDA were patent in her. In last case who had CABG 7 years, two of the three SVG grafts were blocked which were well-demonstrated on CT CAG, including one SVG missed on conventional CAG.

Conclusion:

CT-CAG is a non-invasive and less cumbersome alternative to conventional CAG for the assessment of grafts long after CABG even in women. The data generated by CT-CAG in post-CABG are as good as the invasive CAG and it has distinct advantage of greater acceptability.

A systematic review and meta-analysis of multidetector computed tomography in the assessment of coronary artery bypass grafts

PURPOSE

The present meta-analysis aimed to compare the diagnostic accuracy of more recent computed tomography coronary angiography (CTCA) with invasive coronary angiography (ICA) in the assessment of graft patency after coronary artery bypass graft surgery (CABG).

MATERIAL AND METHODS

A systematic review was performed using nine electronic databases from their dates of inception to July 2015. Predefined inclusion criteria included studies reporting on comparative outcomes using ≥64 slice multidetector computed tomography (MDCT) and ICA. The primary endpoints included graft occlusion and significant graft stenosis ≥50%. Secondary analyses included the comparison of arterial versus venous graft conduits, and the use of different MDCT techniques.

RESULTS

Thirty-one studies were identified according to selection criteria, involving 1975 patients with 5364 assessed grafts. Combined assessment of stenosis and occlusion for all grafts demonstrated a sensitivity of 96.1% [95% confidence interval (CI) 94.3-97.4%] and specificity of 96.3% (95% CI 95.1-97.3%). CTCA assessment of venous grafts demonstrated higher sensitivity compared to arterial grafts, when testing for both occlusion and stenosis (97.6% vs 89.2%, p=0.004).

CONCLUSION

Results of this study demonstrated that CTCA had a relatively high pooled sensitivity, specificity and negative predictive value compared to ICA. However, patient baseline characteristics varied between studies, and the results should be interpreted with caution. Nonetheless, our results indicate that CTCA should be recognized as an accurate and non-invasive investigation for graft patency in symptomatic patients after CABG.