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Prognostic value of stress myocardial perfusion single photon emission computed tomography imaging in patients with
N Nallamothu1, B Bagheri, E R Acio
1Department of Medicine, MCP-Hahnemann School of Medicine, The Allegheny University of the Health Sciences, Philadelphia, Pa 19102, USA.
Insights
Left bundle branch block (LBBB) increases cardiovascular event risk. Stress thallium-201 imaging helps predict outcomes, with perfusion defect size and lung uptake identifying high-risk patients.
Area of Science:
- Cardiology
- Nuclear Cardiology
- Diagnostic Imaging
Background:
- Left bundle branch block (LBBB) can occur independently or with structural heart disease.
- In patients with coronary artery disease (CAD), LBBB is linked to a higher risk of adverse cardiovascular events.
Purpose of the Study:
- To assess the prognostic value of stress thallium-201 single photon emission computed tomography (SPECT) in patients with LBBB and symptoms.
- To identify predictors of cardiac events in this patient cohort.
Main Methods:
- The study included 293 medically treated patients with LBBB and symptoms undergoing stress thallium-201 SPECT.
- Follow-up averaged 33 months, during which hard cardiac events (death, myocardial infarction) and total events were recorded.
- Univariate and multivariate Cox survival analyses were performed using clinical, stress, hemodynamic, and SPECT variables.
Main Results:
- Perfusion defect size and increased lung thallium uptake were the strongest independent predictors of cardiac events.
- Patients with large perfusion defects had significantly lower hard and total event-free survival rates compared to those with small defects.
- High-risk stratification was observed in patients with large perfusion defects and increased lung uptake, showing a higher total event rate.
Conclusions:
- Stress thallium-201 SPECT is valuable for predicting outcomes in patients with LBBB and intermediate pretest probability of CAD.
- Perfusion abnormality size and lung thallium uptake effectively stratify patients into distinct risk groups for cardiac events.
Background:
Left bundle branch block (LBBB) may occur with or without structural heart disease. In patients with coronary artery disease the presence of LBBB is associated with an increased risk of cardiovascular events.
Methods And Results:
This study examined the outcome of 293 medically treated patients with LBBB and symptoms who were undergoing stress thallium-201 single photon emission computed tomography imaging. One hundred seventy-three men and 120 women with an age range of 67 +/- 9 years and a pretest probability of coronary artery disease of 77% +/- 28% were studied. During a mean follow-up of 33 months 58 hard cardiac events (death or nonfatal myocardial infarction) and 112 total events (hard events, coronary angioplasty, coronary bypass surgery, or cardiac transplantation) occurred. Univariate and multivariate Cox survival analysis with clinical, stress, hemodynamic, and single photon emission computed tomography variables identified the perfusion defect size (chi square = 27, p = 0.0001) and increased lung thallium uptake as the most important independent predictors of hard or total cardiac events. The hard event-free survival rate was 91% in patients with no or small defects (<15% of left ventricular myocardium) and 72% in patients with large defects (p = 0.0001, RR = 3.2, 95% CI 1.7 to 5.9). The total event-free survival rate was 81% in patients with small defects and 48% in patients with large defects (p = 0.0001, RR = 2.7, 95% CI 1.9 to 4.0). The total event rate was 54% in patients with large perfusion defects and increased lung uptake and 17% in patients with no or small abnormality and normal lung thallium uptake (p = 0.0001).
Conclusion:
Single photon emission computed tomography perfusion imaging is useful in predicting outcome in patients with LBBB and intermediate pretest probability of coronary artery disease. The size of perfusion abnormality and lung thallium uptake stratified patients into high and low risk groups with a threefold difference in hard and total cardiac events.