Comparison of Four-Dimensional Flow MRI, Two-Dimensional Phase-Contrast MRI and Echocardiography in Transposition of the Great Arteries.

Pulmonary artery (PA) stenosis is a common complication after the arterial switch operation (ASO) for transposition of the great arteries (TGA). Four-dimensional flow (4D flow) CMR provides the ability to quantify flow within an entire volume instead of a single plane. The aim of this study was to compare PA maximum velocities and stroke volumes between 4D flow CMR, two-dimensional phase-contrast (2D PCMR) and echocardiography. A prospective study including TGA patients after ASO was performed between December 2018 and October 2020. All patients underwent echocardiography and CMR, including 2D PCMR and 4D flow CMR. Maximum velocities and stroke volumes were measured in the main, right, and left PA (MPA, LPA, and RPA, respectively). A total of 39 patients aged 20 ± 8 years were included. Maximum velocities in the MPA, LPA, and RPA measured by 4D flow CMR were significantly higher compared to 2D PCMR (p < 0.001 for all). PA assessment by echocardiography was not possible in the majority of patients. 4D flow CMR maximum velocity measurements were consistently higher than those by 2D PCMR with a mean difference of 65 cm/s for the MPA, and 77 cm/s for both the RPA and LPA. Stroke volumes showed good agreement between 4D flow CMR and 2D PCMR. Maximum velocities in the PAs after ASO for TGA are consistently lower by 2D PCMR, while echocardiography only allows for PA assessment in a minority of cases. Stroke volumes showed good agreement between 4D flow CMR and 2D PCMR.

4D flow cardiovascular magnetic resonance derived energetics in the Fontan circulation correlate with exercise capacity and CMR-derived liver fibrosis/congestion.

AIM: This study explores the relationship between in vivo 4D flow cardiovascular magnetic resonance (CMR) derived blood flow energetics in the total cavopulmonary connection (TCPC), exercise capacity and CMR-derived liver fibrosis/congestion. BACKGROUND: The Fontan circulation, in which both caval veins are directly connected with the pulmonary arteries (i.e. the TCPC) is the palliative approach for single ventricle patients. Blood flow efficiency in the TCPC has been associated with exercise capacity and liver fibrosis using computational fluid dynamic modelling. 4D flow CMR allows for assessment of in vivo blood flow energetics, including kinetic energy (KE) and viscous energy loss rate (EL). METHODS: Fontan patients were prospectively evaluated between 2018 and 2021 using a comprehensive cardiovascular and liver CMR protocol, including 4D flow imaging of the TCPC. Peak oxygen consumption (VO2) was determined using cardiopulmonary exercise testing (CPET). Iron-corrected whole liver T1 (cT1) mapping was performed as a marker of liver fibrosis/congestion. KE and EL in the TCPC were computed from 4D flow CMR and normalized for inflow. Furthermore, blood flow energetics were compared between standardized segments of the TCPC. RESULTS: Sixty-two Fontan patients were included (53% male, 17.3 ± 5.1 years). Maximal effort CPET was obtained in 50 patients (peak VO2 27.1 ± 6.2 ml/kg/min, 56 ± 12% of predicted). Both KE and EL in the entire TCPC (n = 28) were significantly correlated with cT1 (r = 0.50, p = 0.006 and r = 0.39, p = 0.04, respectively), peak VO2 (r = - 0.61, p = 0.003 and r = - 0.54, p = 0.009, respectively) and % predicted peak VO2 (r = - 0.44, p = 0.04 and r = - 0.46, p = 0.03, respectively). Segmental analysis indicated that the most adverse flow energetics were found in the Fontan tunnel and left pulmonary artery. CONCLUSIONS: Adverse 4D flow CMR derived KE and EL in the TCPC correlate with decreased exercise capacity and increased levels of liver fibrosis/congestion. 4D flow CMR is promising as a non-invasive screening tool for identification of patients with adverse TCPC flow efficiency.

Baffle Complications in Adults After Atrial Switch for Transposition of the Great Arteries.

BACKGROUND: Baffle complications, ie, leakage or stenosis, after an atrial switch operation (AtrSO) for transposition of the great arteries (TGA) are difficult to detect with the use of routine transthoracic echocardiography (TTE). We examined baffle interventions and the prevalence of baffle complications. METHODS: This dual-centre study followed TGA-AtrSO patients for the occurrence of baffle interventions. In addition, in 2017-2019, prevalence of baffle complications was determined in patients undergoing routine contrast-enhanced (CE) TTE including various hemodynamic conditions and computed tomography (CT). Baffle leaks were defined as right-to-left shunting on CE-TTE and baffle stenosis as a systemic venous baffle diameter of < 10 mm on CT. RESULTS: In total, 67 TGA-AtrSO patients were followed to a median age of 38 (interquartile range 34-42) years, for a median of 9 (6-13) years. Baffle interventions were documented in 24 patients (36%). Cumulative risk of baffle interventions was 25% after 15 years of follow-up. Prevalence of baffle complications was determined in 29/67 patients. In total, 4 (14%) had patent baffles, 11 (38%) had leakage only, 5 (17%) had stenosis only, and 9 (31%) had both, while 24/29 (84%) were asymptomatic. Although baffle leaks were not associated with clinical characteristics, peak work rate during exercise TTE was lower in patients with vs without stenosis (89 ± 24 W vs 123 ± 21 W; P < 0.001). CONCLUSIONS: Baffle complications are common in TGA-AtrSO. The cumulative risk of baffle interventions was 25% after 15 years of follow-up. CE-TTE uncovered asymptomatic baffle leakage in the majority of patients, especially with examination during exercise. CT revealed baffle stenosis in almost half of the patients, which was associated with decreased exercise tolerance. Awareness of these findings may alter clinical follow-up.

Reduced scan time and superior image quality with 3D flow MRI compared to 4D flow MRI for hemodynamic evaluation of the Fontan pathway.

Long scan times prohibit a widespread clinical applicability of 4D flow MRI in Fontan patients. As pulsatility in the Fontan pathway is minimal during the cardiac cycle, acquiring non-ECG gated 3D flow MRI may result in a reduction of scan time while accurately obtaining time-averaged clinical parameters in comparison with 2D and 4D flow MRI. Thirty-two Fontan patients prospectively underwent 2D (reference), 3D and 4D flow MRI of the Fontan pathway. Multiple clinical parameters were assessed from time-averaged flow rates, including the right-to-left pulmonary flow distribution (main endpoint) and systemic-to-pulmonary collateral flow (SPCF). A ten-fold reduction in scan time was achieved [4D flow 15.9 min (SD 2.7 min) and 3D flow 1.6 min (SD 7.8 s), p < 0.001] with a superior signal-to-noise ratio [mean ratio of SNRs 1.7 (0.8), p < 0.001] and vessel sharpness [mean ratio 1.2 (0.4), p = 0.01] with 3D flow. Compared to 2D flow, good-excellent agreement was shown for mean flow rates (ICC 0.82-0.96) and right-to-left pulmonary flow distribution (ICC 0.97). SPCF derived from 3D flow showed good agreement with that from 4D flow (ICC 0.86). 3D flow MRI allows for obtaining time-averaged flow rates and derived clinical parameters in the Fontan pathway with good-excellent agreement with 2D and 4D flow, but with a tenfold reduction in scan time and significantly improved image quality compared to 4D flow.

Echocardiography and MRI parameters associated with exercise capacity in patients after the arterial switch operation.

BACKGROUND: The arterial switch operation (ASO) for transposition of the great arteries has excellent survival, but a substantial number of patients suffer from a reduced exercise capacity. The goal of this study was to identify imaging parameters associated with a reduced exercise capacity in patients after ASO. METHODS: A retrospective analysis was performed of ASO patients who underwent cardiopulmonary exercise testing (CPET) between 2007 and 2017. Reduced exercise performance was defined as a reduced workload peak (Wpeak) with Z-score <-2 or a peak oxygen uptake indexed for weight (VO2peak/kg) with Z-score <-2. Data on echocardiography and cardiac magnetic resonance performed within 1 year of the CPET were collected for comparison. RESULTS: A total of 81 ASO patients (age 17±7 years) were included. Reduced exercise performance was found in 22 patients (27%) as expressed by either a reduced Wpeak and/or a reduced VO2peak/kg. Main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced Wpeak (p=0.031; p=0.020, respectively). The main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced VO2peak/kg (p=0.009; p=0.019, respectively). No left ventricular parameters were found to be associated with abnormal exercise performance. CONCLUSION: This study demonstrates that ASO patients frequently experience reduced exercise capacity. Echocardiographic evidence of main pulmonary artery stenosis and increased right ventricular pressure were associated with reduced exercise capacity, and are therefore key to monitor during serial follow-up of ASO patients.

Medium-term systemic blood pressure after stenting of aortic coarctation: a systematic review and meta-analysis.

OBJECTIVE: Long-term prognosis of patients with coarctation of the aorta (CoA) is impaired due to the high prevalence of hypertension and consequent cardiovascular complications. Although stent implantation results in acute anatomical and haemodynamic benefit, limited evidence exists regarding the late clinical outcome. In this meta-analysis, we aimed to evaluate the medium-term effect of stent placement for CoA on systemic blood pressure (BP). METHODS: PubMed, EMBASE and Cochrane databases were searched for non-randomised cohort studies addressing systemic BP ≥12 months following CoA stenting. Meta-analysis was performed on the change in BP from baseline to last follow-up using a random-effects model. Subgroup analyses and meta-regression were conducted to identify sources of heterogeneity between studies. RESULTS: Twenty-six studies with a total of 1157 patients and a median follow-up of 26 months were included for final analysis. Meta-analysis showed a 20.3 mm Hg (95% CI 16.4 to 24.1 mm Hg; p<0.00001) reduction in systolic BP and an 8.2 mm Hg (12 studies; 95% CI 5.2 to 11.3 mm Hg; p<0.00001) reduction in diastolic BP. A concomitant decrease in the use of antihypertensive medication was observed. High systolic BP and peak systolic gradient at baseline and stenting of native CoA were associated with a greater reduction in systolic BP at follow-up. CONCLUSIONS: Stent implantation for CoA is associated with a significant decline in systolic and diastolic BP during medium-term follow-up. The degree of BP reduction appears to be dependent on baseline systolic BP, baseline peak systolic gradient, and whether stenting is performed for native or recurrent CoA.

Non-HLA Genetic Factors and Their Influence on Heart Transplant Outcomes: A Systematic Review.

BACKGROUND: Improvement of immunosuppressive therapies and surgical techniques has increased the survival rate after heart transplantation. Nevertheless, a large number of patients still experience complications, such as allograft rejection, vasculopathy, kidney dysfunction, and diabetes in response to immunosuppressive therapy. Variants in HLA genes have been extensively studied for their role in clinical outcomes after transplantation, whereas the knowledge about non-HLA genetic variants in this setting is still limited. Non-HLA polymorphisms are involved in the metabolism of major immunosuppressive therapeutics and may play a role in clinical outcomes after cardiac transplantation. This systematic review summarizes the existing knowledge of associations between non-HLA genetic variation and heart transplant outcomes. METHODS: The current evidence available on genetic polymorphisms associated with outcomes after heart transplantation was identified by a systematic search in PubMed and Embase. Studies reporting on polymorphisms significantly associated with clinical outcomes after cardiac transplantation were included. RESULTS: A total of 56 studies were included, all were candidate gene studies. These studies identified 58 polymorphisms in 36 genes that were associated with outcomes after cardiac transplantation. Variants in TGFB1, CYP3A5, and ABCB1 are consistently replicated across multiple studies for various transplant outcomes. CONCLUSIONS: The research currently available supports the hypothesis that non-HLA polymorphisms are associated with clinical outcomes after heart transplantation. However, many genetic variants were only identified in a single study, questioning their true effect on the clinical outcomes tested. Further research in larger cohorts with well-defined phenotypes is warranted.

Percutaneous Pulmonary Valve Implantation: Current Status and Future Perspectives.

Patients with congenital heart disease (CHD) with right ventricle outflow tract (RVOT) dysfunction need sequential pulmonary valve replacements throughout their life in the majority of cases. Since their introduction in 2000, the number of percutaneous pulmonary valve implantations (PPVI) has grown and reached over 10,000 procedures worldwide. Overall, PPVI has been proven safe and effective, but some anatomical variations can limit procedural success. This review discusses the current status and future perspectives of the procedure.

Effect of stent implantation on blood pressure control in adults with coarctation of the aorta.

BACKGROUND: Stenting of coarctation of the aorta (CoA) generally results in good angiographic results and a decrease in transcoarctation pressure gradient. However, effect on blood pressure control is less clear. The goal of the current retrospective analysis was to investigate the effects of CoA stenting on blood pressure control. METHODS: A retrospective analysis was conducted in consecutive adult patients with a CoA who underwent a percutaneous intervention at one of the three participating hospitals. Measurements included office blood pressure, invasive peak-to-peak systolic pressure over the CoA, diameter of the intima lumen at the narrowest part of the CoA and use of medication. The follow-up data were obtained, based on the most recent examination date. RESULTS: There were 26 native CoA and 17 recurrent CoAs (total n = 43). Seven of them underwent two procedures. Mean peak-to-peak gradient decreased from 27 mmHg to 3 mmHg (p < 0.001), and minimal diameter increased from a mean of 11 mm to 18 mm (p < 0.001). Mean systolic blood pressure decreased from 151 ±â€¯18 mmHg to 135 ±â€¯19 mmHg at first follow-up of 3.8 ±â€¯1.9 months and 137 ±â€¯22 mmHg at latest follow-up of 19.5 ±â€¯10.9 months (p = 0.001 and p = 0.009, compared to baseline, respectively). The total number of hypertensive patients decreased from 74% to 27% at latest follow-up. No significant change in antihypertensive medication was observed. CONCLUSION: A clinically significant decrease in systolic blood pressure of approximately 16 mmHg was shown after (re)intervention in CoA patients, which sustained at follow-up. This sustained decrease of blood pressure can be expected to lead to less future adverse cardiovascular events.

Anomalous coronary artery originating from the opposite sinus of Valsalva (ACAOS), fractional flow reserve- and intravascular ultrasound-guided management in adult patients.

OBJECTIVES: To describe the use of fractional flow reserve (FFR) and intravascular ultrasound (IVUS) in the evaluation of patients with anomalous coronary arteries originating from the opposite sinus of Valsalva (ACAOS). BACKGROUND: ACAOS of the right and left coronary are rare, but may lead to symptoms and impose a risk for sudden cardiac death, depending on several anatomical features. Assessment and risk estimation is challenging in (nonathlete) adults, especially if they present without symptoms or with atypical complaints. METHODS: The team retrospectively studied 30 consecutive patients with ACAOS with interarterial course, who received IVUS- and FFR-guided treatment at our institution between October 2010 and September 2017. RESULTS: FFR was abnormal in only seven patients. IVUS showed the typical slit-like anatomy of the orifice in 23 patients. Based on FFR and/or IVUS results, in conjunction with the clinical presentation, clinical decision was made. A decision for intervention was made if at least two out of three entities were abnormal. Intervention implied unroofing of the coronary artery (n = 10) or coronary artery bypass grafting (n = 1). In all other patients a conservative strategy was followed. No adverse events occurred in the total population after a median of 37 (0-62) months of follow-up. CONCLUSIONS: Conservative treatment may be justifiable in adult patients with ACAOS in the presence of normal FFR and nonsuspicious symptoms, despite the presence of an interarterial course and/or slitlike orifice on IVUS. We recommend the use of FFR and IVUS in the standard work-up for adult patients with ACAOS and propose the use of a flowchart to aid in decision-making.