Intravascular ultrasound for cardiac allograft vasculopathy detection

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.

Redefining CAV surveillance strategies: Benefits of CCTA vs. ICA

BACKGROUND

Cardiac allograft vasculopathy (CAV) assessment post-heart transplantation (HT) typically relies on invasive coronary angiography (ICA). However, cardiac computed tomography angiography (CCTA) is emerging as a promising alternative due to its potential benefits in economic, safety, and logistical aspects. This study aimed to evaluate the impact of a CCTA program on these aspects in CAV surveillance post-HT.

METHODS

A retrospective single-center study was conducted between March 2021 and February 2023, involving HT patients who underwent either CCTA or ICA.

RESULTS

Among 260 patients undergoing CAV surveillance, 115 (44.2%) patients underwent CCTA, and 145 (55.8%) patients underwent ICA. The CCTA group showed incurred lower overall costs (p ​< ​0.0001) and shorter hospitalization times (p ​< ​0.0001) compared to the ICA group. In terms of safety, CCTA surveillance required significantly lower contrast volumes (p ​< ​0.0001) and lower effective doses (p ​= ​0.03).

CONCLUSION

CCTA emerges as a safe and cost-effective non-invasive alternative for CAV surveillance post-HT, outperforming ICA in terms of safety, logistical aspects, and economic burden.

In the Twilight of Evidence: Is Bypass Surgery Still on the Table for Cardiac Allograft Vasculopathy?

Background: Cardiac allograft vasculopathy (CAV) is a major prognosis-limiting factor in patients undergoing orthotopic heart transplantation (HT). Due to the diffuse involvement of the coronary tree, CAV lesions are often not amenable to percutaneous coronary intervention (PCI), leaving coronary artery bypass grafting (CABG) and retransplantation as primary revascularization options. Aim and Results: The latest guidelines from the International Society for Heart and Lung Transplantation (ISHLT) recognize CABG as a viable option but with a downgraded strength of recommendation. The 2023 ISHLT guidelines now categorize CABG as a Class IIb recommendation (Level of Evidence: C) for highly selected CAV patients with anatomically suitable lesions, a downgrade from the Class IIa recommendation in the 2010 guidelines. This adjustment underscores the persisting reliance on limited, retrospective studies and the lack of substantial new data supporting CABG in CAV management. Our article examines the evidence collected since 2010 on this topic, highlighting key findings and assessing the role of CABG in contemporary transplant practice. This article calls for targeted investigations to better define the role of CABG as a therapeutic option, addressing the gaps in evidence for surgical revascularization in HT patients.

Cardiac allograft vasculopathy outcomes among donation after circulatory death heart transplant recipients

Background

Cardiac allograft vasculopathy (CAV) accounts for significant long-term morbidity and mortality in heart transplant recipients; limited data exist for donation after circulatory death (DCD). Intravascular ultrasound (IVUS) assessment is a gold standard for early diagnosis of CAV and has strong prognostic power.

Methods

We evaluated all consecutive circulatory and brain death heart transplant recipients from January 2020 to March 2022. Patients were followed for need for percutaneous coronary intervention (PCI), development of severe allograft vasculopathy, or death. Among 143 heart transplant recipients, 39 received circulatory death and 104 received brain death hearts.

Results

Baseline characteristics were similar between groups: median age (56.3 vs 53.7 years, p = 0.290), female sex (15% vs 26%, p = 0.265), and sirolimus use (69% vs 53%, p = 0.116). At 1 year, there were no significant differences in maximal intimal thickness (0.49 vs 0.46 mm, p = 0.861) or Stanford classification. During a median follow-up of 793 days [interquartile ranges 618, 1003], there was no difference in the unadjusted or adjusted primary composite outcome of death, PCI, or International Society of Heart and Lung Transplantation cardiac allograft vasculopathy maximal intimal thickness ≥0.6 mm (unadjusted hazard ratio (HR) 0.42, 95% confidence interval (CI): 0.05, 3.48, p = 0.42), event rate 9.6% vs 2.6%, p = 0.29, nor was there a difference in death, PCI or severe IVUS disease (HR 1.44, 95% CI 0.81, 2.56, p = 0.21).

Conclusion

In DCD heart transplant recipients, circulatory death donors did not have a significantly higher risk for coronary allograft vasculopathy by IVUS or related complications at 1 year following transplantation.

Paediatric heart transplantation recipients ≥7 years of age receiving donors with pre-existing coronary atherosclerosis showed progressive coronary artery disease

BACKGROUND

This study aimed to determine the effect of donor-transmitted atherosclerosis on the late aggravation of cardiac allograft vasculopathy in paediatric heart recipients aged ≥7 years.

METHODS

In total, 48 patients were included and 23 had donor-transmitted atherosclerosis (baseline maximal intimal thickness of >0.5 mm on intravascular ultrasonography). Logistic regression analyses were performed to identify risk factors for donor-transmitted atherosclerosis. Rates of survival free from the late aggravation of cardiac allograft vasculopathy (new or worsening cardiac allograft vasculopathy on following angiograms, starting 1 year after transplantation) in each patient group were estimated using the Kaplan-Meier method and compared using the log-rank test. The effect of the results of intravascular ultrasonography at 1 year after transplantation on the late aggravation of cardiac allograft vasculopathy, correcting for possible covariates including donor-transmitted atherosclerosis, was examined using the Cox proportional hazards model.

RESULTS

The mean follow-up duration after transplantation was 5.97 ± 3.58 years. The log-rank test showed that patients with donor-transmitted atherosclerosis had worse survival outcomes than those without (p = 0.008). Per the multivariate model considering the difference of maximal intimal thickness between baseline and 1 year following transplantation (hazard ratio, 22.985; 95% confidence interval, 1.948-271.250; p = 0.013), donor-transmitted atherosclerosis was a significant covariate (hazard ratio, 4.013; 95% confidence interval, 1.047-15.376; p = 0.043).

CONCLUSION

Paediatric heart transplantation recipients with donor-transmitted atherosclerosis aged ≥7 years had worse late cardiac allograft vasculopathy aggravation-free survival outcomes.