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Cardio Diabetes Medicine 2017 331

Post Revascularisation Status - Myocardial

Perfusion Imaging

Dr.Shrikant Solav MD.,
DRM Nuclear Medicine

Consultant in Nuclear Medicine, Pune

Introduction : However, in individuals with coronary artery disease,
Percutaneous revascularisation procedures have rev- the resting perfusion is homogeneous due to laminar
olutionized the field of interventional cardiology. flow and this becomes inhomogeneous under stress.
When subjected to exercise test, there is dispropor-
PAMI (Primary Angioplasty in Myocardial Infarction) tionate dilatation of healthy coronaries as compared
to elective multi-vessel angioplasty are being routine- to a segment supplied by a stenosed artery that re-
ly carried out in cardiac cathlabs. sults in deprivation of adequate blood flow resulting
Surgical revasculisation has also been refined over in perfusion defect.
the period of years to minimally invasive techniques The procedure provides objective assessment of
thereby reducing the peri-operative morbidity. territory wise ischemia. Thus, in a patient with angi-
The purpose of all these procedures is to eliminate na,culprit vessels can be identified with confidence.
or minimize myocardial ischemia. In the post revasculisation period, conventional stress
Patients with typical angina need to be addressed test has limited value to identify restenosis.
with several questions. However, myocardial perfusion study can detect the

1. Is the angina associated with left ventricular dys- precise territory of ischemia/ restenosis.
function? Please note that MPI should be interpreted with cau-
2. Is the angina responding to optimal medical treat- tion in the immediate post PTCA status.
ment? There are following patterns of abnormalities that can
3. Is the angina related to multi-vessel ischemia? OR be seen to indicate restenosis:
4. Is the angina masked/ under estimated because 1. Reversible perfusion defect in a non-revascularised
of co-morbidities such as diabetes? territory- indicates new coronary disease.
An important method to determine ischemic burden 2. Partially reversible perfusion defect in post infarct
is to perform myocardial perfusion imaging. situation- in territory of revascularization indicates
re-stenosis.
The procedure involves administration of radio-tracer
compound at rest followed by imaging using Gamma 3. Persistent perfusion defect in new territory- indi-
Camera to look at the perfusion. In normal individu- cates peri-procedural injury /or new stenosis.
als, there is homogeneous distribution of radiotracer 4. Reversible perfusion defect in revascularised terri-
in all the segments of heart. The procedure is repeat- tory indicates –restenosis.
ed with exercise test (Treadmill test/ Pharmacolog-
ic intervention using adenosine or dobutamine) an 5. Persistent perfusion defect in revascularised
is expected to remain uniform in all the segments territory in absence of prerevascularisation infarc-
as there is uniform vasodilatation of coronaries in tion- indicates restenosis or peri-proceduration injury
response to exercise to meet with high myocardial
demand.

Cardio Diabetes Medicine