Background:
Coronary artery calcium score (CACS) is an anatomic measure of calcified atherosclerosis. Myocardial perfusion defects and reduced myocardial blood flow reserve (MBFR) are physiological measures of ischemia and coronary circulatory health. We aimed to assess the relative prognostic importance of MBFR, perfusion defects, and CACS in patients with suspected coronary artery disease.
Methods:
A total of 5983 consecutive patients without known history of coronary artery disease or cardiomyopathy, who underwent a CACS and
82
Rb positron emission tomography myocardial perfusion imaging between 2010 and 2016, were followed for all-cause death (n=785) over median of 3 years. Prognostic value was assessed using multivariable Cox regression models, and incremental risk discrimination for imaging variables was evaluated by comparing model c-indices after adjusting for clinical risk factors (RF).
Results:
Mean age was 67.1 years, 60% were female, and 83% were symptomatic. CACS was 0 in 22%, abnormal perfusion in 19%, and MBFR <2 in 53.3%. When added to RF, the model with MBFR had the best fit (c=0.78,
P
<0.0001). Addition of CACS to model with RF and perfusion (c=0.77) offered modest improvement in discrimination over the model with RF and perfusion (c=0.76,
P
=0.02). Adding CACS to a model with RF, perfusion, and MBFR did not provide incremental prognostic value (c=0.785 for both,
P
=0.16). CACS and MBFR both had independent prognostic value in patients with normal and abnormal myocardial perfusion imaging. Even among patients with CACS of 0, MBFR <2 was present in 37.8%, being associated with higher risk of death (hazard ratio per 0.1↓, 1.10 [1.04–1.15];
P
<0.001), but perfusion defects were not.
Conclusions:
Use of anatomic testing such as CACS of 0 to avoid myocardial perfusion imaging in symptomatic patients could lead to missing microvascular dysfunction in 4 out of 10 patients, a finding associated with a high mortality risk. Higher CACS was independently associated with the risk of death but did not provide incremental prognostic value over positron emission tomography with MBFR.
Background
In orthotopic heart transplant recipients, surveillance with endomyocardial biopsy is crucial to detect acute cellular rejection (ACR) early. ACR is a common and serious complication of transplantation with substantial morbidity and mortality. Speckle tracking echocardiography with global longitudinal strain (GLS) assessment of the left ventricle has emerged as a possible noninvasive screening modality. We have conducted a systematic literature review and meta‐analysis to evaluate the role of GLS in diagnosing ACR.
Methods
The following databases were queried: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and Embase. We compiled all articles evaluating changes in GLS in comparison to endomyocardial biopsy in ACR dated prior to September 2019. Weighted mean differences (WMD) and 95% confidence intervals (CIs) were pooled by using a random effects model. In order to determine the risk of bias, we used the revised version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS‐2) tool.
Results
Twelve studies met inclusion criteria of which ten were chosen. These studies encompassed 511 patients and 1267 endomyocardial biopsies. There was a significant difference in GLS between patients who did and did not have ACR proven by biopsy (WMD = 2.18; 95% CI: 1.57‐2.78, P = <.001; I2 = 76%). The overall sensitivity for GLS in detecting ACR was 78% (CI: 63%‐90%, P = .123; I2 = 52.2%) while the overall specificity was 68% (CI: 50%‐83%, P = <.001; I2 = 88.3%).
Conclusion
Global longitudinal strain assessment of the left ventricle by speckle tracking echocardiography is useful in detecting ACR and could potentially reduce the burden of frequent endomyocardial biopsies in heart transplant recipients.
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