Significance of inferior wall ischemia in non-dominant right coronary artery anatomy

Non-dominant right coronary artery (RCA) is associated with suspected inferior ischemia on SPECT in patients without significant coronary artery disease (CAD)

OBJECTIVE

There is a huge uncertainty in the medical community regarding the significance of non-dominant right coronary artery (RCA) in patients with inferior wall ischemia on myocardial perfusion single-photon emission computed tomography (SPECT). The purpose of this study is to determine the effect of non-dominant RCA on myocardial perfusion SPECT (MPS) with respect to the misleading detection of ischemia in the inferior wall of the myocardium.

METHODS

This is a retrospective study of 155 patients, who had undergone elective coronary angiography owing to an indication of inferior wall ischemia by MPS between 2012 and 2017. Patients were divided into two groups based on the coronary dominance: group 1 (n = 107), if RCA is the dominant artery, and group 2 (n = 48), if there are dominance of left artery and codominance of both arteries. Obstructive CAD was diagnosed in the case of stenosis that had severity greater than 50%. The positive predictive value (PPV), which was calculated as per the correlation between the inferior wall ischemia in MPS and obstruction level in RCA, was compared in both groups.

RESULTS

Majority of patients were male (109, 70%) and the mean age was 59.5 ± 10.2. There were 45 patients with obstructive RCA disease (PPV: 42%) among 107 patients in group 1, whereas there were only 8 patients with obstructive coronary artery disease (CAD) in RCA among 48 patients in group 2, (PPV: 16% and p = 0.004).

CONCLUSIONS

The results demonstrated that non-dominant RCA is associated with false-positive detection of inferior wall ischemia via MPS.

Inferior myocardial wall ischemia on SPECT-MPI in patients with non dominant right coronary artery and non significant coronary artery disease

BACKGROUND

The impact of a non-dominant right coronary artery (NDRCA), on single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI)has not been clarified.

METHODS AND RESULTS

We compared SPECT-MPI results of consecutive patients without significant (diameter stenosis ≥50%)coronary artery disease (CAD) and a NDRCA (Group-1), with those of patients from our database without CAD and a dominant RCA (Group-2). All patients were subjected to SPECT-MPI with I.V. infusion of adenosine, and TC⁹⁹-tetrofosmin. Group-1 included 69 patients (55 men, 79.7%), mean age 66.8 ± 9.8 years. Group-2 consisted of 79 patients (56 men, 70.9%), mean age 62.7 ± 11.5. There was no difference in demographics and CAD risk factors between the two groups. The SPECT-MPI revealed inferior wall ischemia, in 35 patients (50.7%), in Group-1 and 27 patients (34.1%), in Group-2 (P = 0.041).

CONCLUSIONS

A relatively high rate of reversible SPECT-MPI perfusion defects may be anticipated in patients with an unobstructed NDRCA compared to patients with a dominant RCA.

An unusual anatomic variation of the Posterior Descending Coronary Artery

PURPOSE

To report a rare coronary anatomic variation.

METHODS

Review of the coronary angiogram of a patient with evidence of myocardial ischemia.

RESULTS

The posterior descending artery was aberrant, originating from a large intermediate brunch.

CONCLUSION

This anatomic variation has not been previously described.