Coronary-to-pulmonary artery fistula in adults: Evaluation with thallium-201 myocardial perfusion SPECT

Abstract

ObjectivesWith the increasing use of multi-detector CT, the number of detected cases with coronary-to-pulmonary artery fistula (CPAF) has increased. Several previous studies reported severe cases of angina, but no appropriate tests to evaluate myocardial perfusion for patients with CPAF have been established. We evaluated the hemodynamic characteristics of CPAF using thallium-201 (Tl-201) single photon emission computed tomography (SPECT).Materials and methodsTl-201 SPECT was performed in 17 patients with CPAF, but without evidence of coronary artery disease on coronary computed tomography angiography (CCTA) (age, 58.5±13.3 years; 8 men). Quantitative analysis of scintigraphic data was performed. Additionally, perfusion abnormalities were compared with CCTA findings. Medical records were obtained to define clinical data, diagnostic findings, symptoms, management, follow-up data, and major adverse cardiac events (MACE).ResultsSix patients (35.2%) showed perfusion abnormalities on SPECT studies and could be classified as follows: 3 patients, no reversible ischemia (3/17, 17.6%); 1 patient, mild ischemia (1/17, 5.8%); and 2 patients, moderate ischemia (2/17, 11.7%). During the follow-up, ten patients (58.8%) improved under medical management and 5 patients (29.4%) underwent surgical ligation for CPAF with symptomatic improvement in 4 patients. Seven patients performed follow-up myocardial perfusion SPECT, and symptomatic improvement correlated well with scintigraphic perfusion improvement in 6 patients No MACE was observed.Clinical significanceTl-201 myocardial perfusion SPECT might be useful for determining the hemodynamic status and for risk stratification in patients with CPAF.

Right Coronary Artery-Superior Vena Cava Fistula Manifesting as NSTEMI: Case Report, Review of Imaging, and Summary of Guidelines

“…According to the 2008 ACC/AHA guidelines, CAFs that should be evaluated for closure are large fistulas regardless of symptomology, and small to moderate fistulas that are associated with myocardial ischemia, arrhythmia, endarteritis, unexplained ventricular diastolic or systolic dysfunction, and ventricular dilation [17]. If a CAF is incidentally discovered on imaging and considered to be the etiology of angina, myocardial ischemia can be evaluated with exercise stress testing or myocardial perfusion scanning [3,27,30]. CAF size characterization is defined with angiography and in reference to the distal vessel lumen, with a large CAF being greater than 2x the diameter of the distal vessel, and small to moderate being less than 1–2x the distal vessel diameter [20].…”

Incidental congenital coronary artery vascular fistulas in adults: Evaluation with adenosine-13N-ammonia PET-CT

“…A report by Gupta et al[ 46 ] in 1991, followed by Glynn et al[ 47 ] in 1994, reported the first case studies documenting the use of thallium-201 perfusion imaging for physiological assessment of CAF (LAD-PA) and as the cause of an exercise-induced reversible thallium-201 perfusion defect in an adult patient[ 46 , 47 ]. The pharmacological stress MPI SPECT technique may indicate segmental perfusion defects in patients with congenital CPF in the absence of CAD[ 11 ]. In a patient series evaluated by Lee et al[ 11 ], 35% of patients with congenital CPF without CAD developed perfusion defects, but the findings were only clinically relevant in 12%.…”

“…The pharmacological stress MPI SPECT technique may indicate segmental perfusion defects in patients with congenital CPF in the absence of CAD[ 11 ]. In a patient series evaluated by Lee et al[ 11 ], 35% of patients with congenital CPF without CAD developed perfusion defects, but the findings were only clinically relevant in 12%.…”

“…Adenosine stress-induced 13 N-ammonia PET-CT uptake in the myocardium is related to perfusion and may offer better assessment of myocardial ischemia. Adenosine stress 13 N-ammonia PET-CT has several advantages over SPECT, such as higher spatial resolution and sensitivity, absolute quantification, better counting efficiency and improved attenuation correction[ 11 , 24 ]. In 2011, a report described the application of adenosine 13 N-ammonia PET-CT in congenital CAFs for the first time[ 19 ].…”

“…CAFs are classified as anomalies of termination[ 7 ]. Several diagnostic modalities are available for the morphological and functional detection of CAFs, including physical examination (presence of a continuous murmur), non-invasive methods such as echocardiography[ 8 , 9 ], myocardial perfusion imaging (MPI)[ 10 , 11 ], CTCA[ 3 , 9 , 12 ] and cardiovascular magnetic resonance imaging (MRI)[ 13 ], invasive techniques such as right heart catheterization, CAG and fractional flow reserve (FFR)[ 1 , 14 - 18 ], and incidental detection during positron emission tomography computed tomography (PET-CT)[ 19 , 20 ]. Exercise and pharmacological PET-CT is commonly applied for the assessment of myocardial perfusion and ischemia, and for the diagnosis and risk stratification of ischemic coronary artery disease (CAD)[ 21 , 22 ].…”