Cardiac PET helps assess revascularization benefits
CHICAGO - By performing myocardial perfusion imaging (MPI) with cardiac FDG-PET before revascularization, clinicians can better assess the benefits of that procedure and predict near-term outcomes for patients with coronary artery disease and left ventricular dysfunction, according to a study presented on Sunday at RSNA 2018.
Researchers from New Delhi found that resting-state MPI cardiac PET scans confirmed improvement in left ventricular ejection fraction after revascularization, which also proved significantly better than optimum medical treatment in preventing an adverse cardiac event within one year.
"The findings signify the significant impact of revascularization on patients' functional status and quality of life," said study co-author Dr. Ritu Verma from Sir Ganga Ram Hospital.
Myocardial perfusion imaging is seen as the prime method of identifying hibernating myocardium in patients with coronary artery disease and left ventricular dysfunction. Hibernating myocardium is characterized by reduced or absent systolic contraction with persistent and reduced resting perfusion. However, the condition can be treated with revascularization, even in patients with severe coronary artery disease.
By using cardiac PET to predict recovery from hibernating myocardium after revascularization, clinicians can also provide the best overall treatment strategy.
"These patients are representative of the population physicians often express concerns about regarding the risks and benefits of revascularization," Verma told RSNA attendees.
The researchers enrolled 59 consecutive patients (43 men, 16 women; mean age, 60.7 ± 9.4 years) with coronary artery disease and left ventricular systolic dysfunction. The patients had comorbidities such as hypertension and left ventricular ejection fraction (LVEF) of less than 35%. The normal range for LVEF is 55% to 70%.
Among the subjects, 29 (49%) underwent revascularization through percutaneous angioplasty or coronary artery bypass grafting (CABG), while 25 (42%) received optimum medical treatment. Five patients were lost during the follow-up period.
The benefits of both therapeutic approaches were evaluated using three categories:
- Changes in left ventricular function based on New York Heart Association (NYHA) parameters after revascularization
- Improvement in left ventricular diastolic and systolic functions and myocardial perfusion on follow-up resting-state technetium-99m sestamibi MPI
- Adverse cardiac events during a median follow-up time of 7.7 months
On follow-up resting MPI scans, the mean improvement in left ventricular ejection fraction in the revascularization group was significantly higher (6%) than in the optimum medical treatment group (1.4%) (p = 0.04).
In addition, the optimum medical treatment group had significantly more cardiac events (nine, 36%) than the revascularization group (three, 10.3%) (p = 0.046). At one-year follow-up, event-free survival in the revascularization group (83.8%) was also significantly superior to survival in the other group (50.8%) (p = 0.039).
"The take-home message is that cardiac PET is the gold standard for myocardial viability assessment and the detection of hibernating myocardium," Verma concluded. "Subsequently, revascularization reduces the overall scope of morbidity and mortality."