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Evaluation of a comprehensive cardiovascular magnetic resonance protocol in young adults late after the arterial switch operation for d-transposition of the great arteries.

Tobler D, Motwani M, Wald RM, Roche SL, Verocai F, Iwanochko RM, Greenwood JP, Oechslin EN, Crean AM - J Cardiovasc Magn Reson (2014)

Bottom Line: In 24 cases the coronary ostia could conclusively be demonstrated to be normal.The data shows that the asymptomatic and clinically stable adult ASO patient has a low pre-test probability for inducible ischemia.In this situation it is likely that routine evaluation with stress CMR is unnecessary.

View Article: PubMed Central - PubMed

Affiliation: Toronto Congenital Centre for Adults, Peter Munk Cardiac Centre, University Health Network, Toronto General Hospital, 585 University Avenue, 5 N-525, Toronto M5G 2N2, ON, Canada. andrew.crean@uhn.ca.

ABSTRACT

Background: In adults with prior arterial switch operation (ASO) for d-transposition of the great arteries, the need for routine coronary artery assessment and evaluation for silent myocardial ischemia is not well defined. In this observational study we aimed to determine the value of a comprehensive cardiovascular magnetic resonance (CMR) protocol for the detection of coronary problems in adults with prior ASO for d-transposition of the great arteries.

Methods: Adult ASO patients (≥18 years of age) were recruited consecutively. Patients underwent a comprehensive stress perfusion CMR protocol that included measurement of biventricular systolic function, myocardial scar burden, coronary ostial assessment and myocardial perfusion during vasodilator stress by perfusion CMR. Single photon emission computed tomography (SPECT) was performed on the same day as a confirmatory second imaging modality. Stress studies were visually assessed for perfusion defects (qualitative analysis). Additionally, myocardial blood flow was quantitatively analysed from mid-ventricular perfusion CMR images. In unclear cases, CT coronary angiography or conventional angiography was done.

Results: Twenty-seven adult ASO patients (mean age 23 years, 85% male, 67% with a usual coronary pattern; none with a prior coronary artery complication) were included in the study. CMR stress perfusion was normal in all 27 patients with no evidence of inducible perfusion defects. In 24 cases the coronary ostia could conclusively be demonstrated to be normal. There was disagreement between CMR and SPECT for visually-assessed perfusion defects in 54% of patients with most disagreement due to false positive SPECT.

Conclusions: Adult ASO survivors in this study had no CMR evidence of myocardial ischemia, scar or coronary ostial abnormality. Compared to SPECT, CMR provides additional valuable information about the coronary artery anatomy. The data shows that the asymptomatic and clinically stable adult ASO patient has a low pre-test probability for inducible ischemia. In this situation it is likely that routine evaluation with stress CMR is unnecessary.

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Example of a false positive SPECT with moderate ‘inducible ischemia’. (Ai-ii) MIBI bulls eye plots demonstrating a defect at stress in the basal to mid anterolateral wall (i) which appears fully reversible at rest (ii) with a SDS of 5 (iii) suggesting a moderate inducible perfusion defect. (Bi-iii) Basal, mid and apical short axis slices from stress CMR show visually normal perfusion in all territories. Quantitative perfusion (not shown) confirmed normal stress perfusion values at the sites of the defect seen on MIBI. (Ci-iii) Basal, mid and apical short axis slices from LGE stack demonstrate lack of any myocardial scar. (Di-ii) CT coronary angiogram performed in view of the discordance between SPECT and CMR shows that the coronary arteries are entirely normal.
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Fig7: Example of a false positive SPECT with moderate ‘inducible ischemia’. (Ai-ii) MIBI bulls eye plots demonstrating a defect at stress in the basal to mid anterolateral wall (i) which appears fully reversible at rest (ii) with a SDS of 5 (iii) suggesting a moderate inducible perfusion defect. (Bi-iii) Basal, mid and apical short axis slices from stress CMR show visually normal perfusion in all territories. Quantitative perfusion (not shown) confirmed normal stress perfusion values at the sites of the defect seen on MIBI. (Ci-iii) Basal, mid and apical short axis slices from LGE stack demonstrate lack of any myocardial scar. (Di-ii) CT coronary angiogram performed in view of the discordance between SPECT and CMR shows that the coronary arteries are entirely normal.

Mentions: In the remaining 8 cases of disagreement the SDS scores were 2 in four patients, SDS 3 in two patients, SDS 4 in one patient and SDS 5 in the final case (Figure 7). In 6 out of these 8 cases CMR demonstrated normal coronary ostia, perfusion and absent LGE suggesting that the SPECT defects were artifactual. In the two other cases, a small amount of LGE was present in one case (patient 7); in the other case (patient 22), proximal RCA kinking was called, with a small SPECT perfusion defect in the LAD territory that was felt to be artifactual in view of the normal ostial left main appearances and absence of LGE in the anterolateral wall (Figure 4).Figure 7


Evaluation of a comprehensive cardiovascular magnetic resonance protocol in young adults late after the arterial switch operation for d-transposition of the great arteries.

Tobler D, Motwani M, Wald RM, Roche SL, Verocai F, Iwanochko RM, Greenwood JP, Oechslin EN, Crean AM - J Cardiovasc Magn Reson (2014)

Example of a false positive SPECT with moderate ‘inducible ischemia’. (Ai-ii) MIBI bulls eye plots demonstrating a defect at stress in the basal to mid anterolateral wall (i) which appears fully reversible at rest (ii) with a SDS of 5 (iii) suggesting a moderate inducible perfusion defect. (Bi-iii) Basal, mid and apical short axis slices from stress CMR show visually normal perfusion in all territories. Quantitative perfusion (not shown) confirmed normal stress perfusion values at the sites of the defect seen on MIBI. (Ci-iii) Basal, mid and apical short axis slices from LGE stack demonstrate lack of any myocardial scar. (Di-ii) CT coronary angiogram performed in view of the discordance between SPECT and CMR shows that the coronary arteries are entirely normal.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4263214&req=5

Fig7: Example of a false positive SPECT with moderate ‘inducible ischemia’. (Ai-ii) MIBI bulls eye plots demonstrating a defect at stress in the basal to mid anterolateral wall (i) which appears fully reversible at rest (ii) with a SDS of 5 (iii) suggesting a moderate inducible perfusion defect. (Bi-iii) Basal, mid and apical short axis slices from stress CMR show visually normal perfusion in all territories. Quantitative perfusion (not shown) confirmed normal stress perfusion values at the sites of the defect seen on MIBI. (Ci-iii) Basal, mid and apical short axis slices from LGE stack demonstrate lack of any myocardial scar. (Di-ii) CT coronary angiogram performed in view of the discordance between SPECT and CMR shows that the coronary arteries are entirely normal.
Mentions: In the remaining 8 cases of disagreement the SDS scores were 2 in four patients, SDS 3 in two patients, SDS 4 in one patient and SDS 5 in the final case (Figure 7). In 6 out of these 8 cases CMR demonstrated normal coronary ostia, perfusion and absent LGE suggesting that the SPECT defects were artifactual. In the two other cases, a small amount of LGE was present in one case (patient 7); in the other case (patient 22), proximal RCA kinking was called, with a small SPECT perfusion defect in the LAD territory that was felt to be artifactual in view of the normal ostial left main appearances and absence of LGE in the anterolateral wall (Figure 4).Figure 7

Bottom Line: In 24 cases the coronary ostia could conclusively be demonstrated to be normal.The data shows that the asymptomatic and clinically stable adult ASO patient has a low pre-test probability for inducible ischemia.In this situation it is likely that routine evaluation with stress CMR is unnecessary.

View Article: PubMed Central - PubMed

Affiliation: Toronto Congenital Centre for Adults, Peter Munk Cardiac Centre, University Health Network, Toronto General Hospital, 585 University Avenue, 5 N-525, Toronto M5G 2N2, ON, Canada. andrew.crean@uhn.ca.

ABSTRACT

Background: In adults with prior arterial switch operation (ASO) for d-transposition of the great arteries, the need for routine coronary artery assessment and evaluation for silent myocardial ischemia is not well defined. In this observational study we aimed to determine the value of a comprehensive cardiovascular magnetic resonance (CMR) protocol for the detection of coronary problems in adults with prior ASO for d-transposition of the great arteries.

Methods: Adult ASO patients (≥18 years of age) were recruited consecutively. Patients underwent a comprehensive stress perfusion CMR protocol that included measurement of biventricular systolic function, myocardial scar burden, coronary ostial assessment and myocardial perfusion during vasodilator stress by perfusion CMR. Single photon emission computed tomography (SPECT) was performed on the same day as a confirmatory second imaging modality. Stress studies were visually assessed for perfusion defects (qualitative analysis). Additionally, myocardial blood flow was quantitatively analysed from mid-ventricular perfusion CMR images. In unclear cases, CT coronary angiography or conventional angiography was done.

Results: Twenty-seven adult ASO patients (mean age 23 years, 85% male, 67% with a usual coronary pattern; none with a prior coronary artery complication) were included in the study. CMR stress perfusion was normal in all 27 patients with no evidence of inducible perfusion defects. In 24 cases the coronary ostia could conclusively be demonstrated to be normal. There was disagreement between CMR and SPECT for visually-assessed perfusion defects in 54% of patients with most disagreement due to false positive SPECT.

Conclusions: Adult ASO survivors in this study had no CMR evidence of myocardial ischemia, scar or coronary ostial abnormality. Compared to SPECT, CMR provides additional valuable information about the coronary artery anatomy. The data shows that the asymptomatic and clinically stable adult ASO patient has a low pre-test probability for inducible ischemia. In this situation it is likely that routine evaluation with stress CMR is unnecessary.

Show MeSH
Related in: MedlinePlus