CT Coronary Angiography and Dynamic CT Myocardial Perfusion for Detection of Cardiac Allograft Vasculopathy

Temporal changes in CT-derived fractional flow reserve in patients after heart transplantation

BACKGROUND

Adding functional information by CT-derived fractional flow reserve (FFRct) to coronary CT angiography (CCTA) and assessing its temporal change may provide insight into the natural history and physiopathology of cardiac allograft vasculopathy (CAV) in heart transplantation (HTx) patients. We assessed FFRct changes as well as CAV progression over a 2-year period in HTx patients undergoing serial CT imaging.

METHODS

HTx patients from Erasmus MC and Mount Sinai Hospital, who had consecutive CCTAs 2 years apart were evaluated. FFRct analysis was performed for both scans. FFRct values at the most distal point in the left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) were measured after precisely matching the anatomical locations in both analyses. Also, the number of anatomical coronary stenoses of > 30% was scored.

RESULTS

In total, 106 patients (median age 57 [interquartile range 47-67] years, 67% male) at 9 [6-13] years after HTx at the time of the baseline CCTA were included. Median distal FFRct values significantly decreased from baseline to follow-up for the LAD from 0.85 [0.79-0.90] to 0.84 [0.76-0.90] (p = 0.001), LCX from 0.92 [0.88-0.96] to 0.91 [0.85-0.95] (p = 0.009), and RCA from 0.92 [0.86-0.95] to 0.90 [0.86-0.94] (p = 0.004). The number of focal anatomical stenoses of > 30% increased from a median of 1 [0-2] at baseline to 2 [0-3] at follow-up (p = 0.009).

CONCLUSIONS

The distal coronary FFRct values in post-HTX patients in each of the three major coronary arteries decreased, and the number of focal coronary stenoses increased over a 2-year period. Temporal FFRct change rate may become an additional parameter in the follow-up of HTx patients, but more research is needed to elucidate its role.

CLINICAL RELEVANCE STATEMENT

CT-derived fractional flow reserve (FFRct) is important post-heart transplant because of additional information on coronary CT angiography for cardiac allograft vasculopathy (CAV) detection. The decrease and degree of reduction in distal FFRct value may indicate progression in anatomic CAV burden.

KEY POINTS

CT-derived fractional flow reserve (FFRct) is important for monitoring cardiac allograft vasculopathy (CAV) in heart transplant patients. Over time, transplant patients showed a decrease in distal FFRct and an increase in coronary stenoses. Temporal changes in FFRct could be crucial for transplant follow-up, aiding in CAV detection.

Comprehensive Non-invasive Versus Invasive Approach to Evaluate Cardiac Allograft Vasculopathy in Heart Transplantation: The CCTA-HTx Study

BACKGROUND

Coronary computed tomography angiography (CCTA) is emerging as a valuable tool for noninvasive surveillance of cardiac allograft vasculopathy (CAV) in patients with heart transplant (HTx). We assessed the diagnostic performance of a comprehensive CCTA-based approach compared with the invasive reference, which includes invasive coronary angiography, intravascular ultrasound, and fractional flow reserve, for detecting CAV.

METHODS

This was a multicenter prospective study including 37 patients with HTx who underwent CCTA, invasive coronary angiography, intravascular ultrasound, and fractional flow reserve. The comprehensive CCTA-based approach included quantitative and qualitative plaque analysis and functional assessment by fractional flow reserve derived from coronary computed tomography. CAV was diagnosed based on invasive coronary angiography (International Society for Heart and Lung Transplantation criteria) and intravascular ultrasound. Univariable logistic regression analysis was performed to test CCTA-derived predictors of CAV. The area under the curve and accuracy indicators were calculated to evaluate the performance and best cutoffs of CCTA predictors of CAV.

RESULTS

The median interval between CCTA and HTx was 5 years. Among the 37 recipients, 23 (62.2%) were diagnosed with CAV. The integration of diameter stenosis and plaque morphology (including plaque burden at minimum lumen area >42% and percent atheroma volume >23%) at CCTA yielded the highest diagnostic performance (accuracy, 84%; sensitivity, 83%; specificity, 86%). The integration of ∆fractional flow reserve derived from coronary computed tomography trans-vessel gradient led to increased sensitivity, albeit with decreased specificity and overall accuracy. The noninvasive approach was associated with a lower contrast and radiation dose, compared with the invasive approach.

CONCLUSIONS

A noninvasive strategy based on CCTA is accurate for managing patients with HTx. CCTA might be considered the preferred imaging modality for annual CAV surveillance after the first year post-HTx.

Revisiting Biomarkers of Cardiac Allograft Vasculopathy: Addressing the Achilles Heel of Heart Transplantation

Nearly half of heart transplant recipients will be diagnosed with cardiac allograft vasculopathy (CAV) within five years after transplantation. Advanced CAV can lead to worsening heart failure as well as arrhythmias and sudden cardiac death. The only curative therapy for end-stage CAV is re-transplantation. Current diagnostic methods are invasive and limited by poor sensitivity in early disease. Despite its high prevalence in the post-transplantpopulation, the underlying pathophysiology of this condition has yet to be fully described. It is thought to be primarily related to endothelial dysfunction, immune activation, and cardiometabolic disease. Biomarkers reflecting these underlying processes, particularly endothelial injury and immune activation, have shown early promise in discriminating prevalent CAV. Next-generation sequencing technologies such as proteomic and transcriptomic profiling have also provided further insight into the pathophysiology of CAV through the identification of novel biomarkers. Ultimately, these biomarkers may have a role in not only diagnosing CAV but also highlighting potential targets for disease-specific therapies. In this article, we review the current data for biomarkers in CAV and discuss future directions for biomarker identification..

Effect of Evogliptin on the Progression of Aortic Valvular Calcification

BACKGROUND

Medical therapy for aortic stenosis (AS) remains an elusive goal.

OBJECTIVES

This study sought to establish whether evogliptin, a dipeptidyl peptidase-4 inhibitor, could reduce AS progression.

METHODS

A total of 228 patients (age 67 ± 11 years; 33% women) with AS were randomly assigned to receive placebo (n = 75), evogliptin 5 mg (n = 77), or evogliptin 10 mg (n = 76). The primary endpoint was the 96-week change in aortic valve calcium volume (AVCV) on computed tomography. Secondary endpoints included the 48-week change in active calcification volume measured using 18F-sodium fluoride positron emission tomography (18F-NaF PET).

RESULTS

There were no significant differences in the 96-week changes in AVCV between evogliptin 5 mg and placebo (-5.27; 95% CI: -55.36 to 44.82; P = 0.84) or evogliptin 10 mg and placebo (-18.83; 95% CI: -32.43 to 70.10; P = 0.47). In the placebo group, the increase in AVCV between 48 weeks and 96 weeks was higher than that between baseline and 48 weeks (136 mm3; 95% CI: 108-163 vs 102 mm3; 95% CI: 75-129; P = 0.0485). This increasing trend in the second half of the study was suppressed in both evogliptin groups. The 48-week change in active calcification volume on 18F-NaF PET was significantly lower in both the evogliptin 5 mg (-1,325.6; 95% CI: -2,285.9 to -365.4; P = 0.008) and 10-mg groups (-1,582.2; 95% CI: -2,610.8 to -553.5; P = 0.0038) compared with the placebo group.

CONCLUSIONS

This exploratory study did not demonstrate the protective effect of evogliptin on AV calcification. Favorable 18F-NaF PET results and possible suppression of aortic valve calcification with longer medication use in the evogliptin groups suggest the need for larger confirmatory trials. (A Multicenter, Double-blind, Placebo-controlled, Stratified-randomized, Parallel, Therapeutic Exploratory Clinical Study to Evaluate the Efficacy and Safety of DA-1229 in Patients With Calcific Aortic Valve Disease; NCT04055883).

The predictive value of coronary artery calcium score combined with traditional risk factors for obstructive coronary heart disease in young people

OBJECTIVES

This study attempts to compare the predictive effects of several prediction models on obstructive coronary artery disease (OCAD) in young patients (30-50 years old), with a view to providing a new evaluation tool for the prediction of premature coronary artery disease (PCAD).

METHODS

A total of 532 hospitalized patients aged 30-50 were included in the study.All of them underwent coronary computed tomography angiography (CCTA) for suspected symptoms of coronary heart disease.Coronary artery calcium score (CACS) combined with traditional risk factors and pre-test probability models are the prediction models to be compared in this study.The PTP model was selected from the upgraded Diamond-Forrester model (UDFM) and the Duke clinical score (DCS).

RESULTS

All patients included in the study were aged 30-50 years. Among them, women accounted for 24.4%, and 355 patients (66.7%) had a CACS of 0. OCAD was diagnosed in 43 patients (8.1%). The CACS combined with traditional risk factors to predict the OCAD area under the curve of receiver operating characteristic (ROC) (AUC = 0.794,p < 0.001) was greater than the PTP models (AUCUDFM=0.6977,p < 0.001;AUCDCS=0.6214,p < 0.001). By calculating the net reclassification index (NRI) and the integrated discrimination index (IDI), the ability to predict the risk of OCAD using the CACS combined with traditional risk factors was improved compared with the PTP models (NRI&IDI > 0,p < 0.05).

CONCLUSION

The predictive value of CACS combined with traditional risk factors for OCAD in young patients is better than the PTP models.

Role of Radiology in Assessment of Postoperative Complications of Heart Transplantation

Heart transplantation is a pivotal treatment of end-stage heart failure, and recent advancements have extended median posttransplant life expectancy. However, despite the progress in surgical techniques and medical treatment, heart transplant patients still face complications such as rejection, infections, and drug toxicity. CT is a reliable tool for detecting most of these complications, whereas MR imaging is particularly adept at identifying pericardial pathologies and signs of rejection. Awareness of these nuances by radiologists, cardiologists, and surgeons is desired to optimize care, reduce morbidities, and enhance survival.