Isolated pulmonary regurgitation causes decreased right ventricular longitudinal function and compensatory increased septal pumping in a porcine model

Patients with volume-loaded right ventricle - quantification of left ventricular hemodynamic response to intervention measured by noninvasive pressure-volume loops

Volume loading of the right ventricle (RV) in patients with atrial septal defect (ASD) and patients with repaired Tetralogy of Fallot (rToF) affects the pumping mechanics of the left ventricle (LV). Intervention of the lesion will relieve the RV volume load however quantifiable impact on exercise capacity, arrhytmias or death are limited. A possible explanation could be remaining effects on the function of the LV. The aim of this study was therefore to investigate if hemodynamics of the LV differs between patients with RV volume load due to ASD or rToF and healthy controls and if they change after intervention. Eighteen patients with ASD, 17 patients with rToF and 16 healthy controls underwent cardiac magnetic resonance imaging (CMR) and maximal exercise test with continuous gas analysis. Reexamination was performed 13 ± 2 months after closure of the ASD in 13 of the patients and 10 ± 4 months after pulmonary valve replacement (PVR) in 9 of the patients with rToF. Non-invasive PV-loops from CMR and brachial pressures were analyzed. Stroke work (SW) and potential energy (PE) increased after ASD closure but not in ToF patients after valve repair. Patients with ASD or rToF had higher contractility and arterial elastance than controls. No major effects were seen in LV energetics or in peak VO2 after ASD closure or PVR. Peak VO2 correlated positively with SW and PE in patients with ASD (r = 0.54, p < 0.05; r = 0.61, p < 0.01) and controls (r = 0.72, p < 0.01; r = 0.53, p < 0.05) to approximately the same degree as peak VO2 and end-diastolic volume (EDV) or end-systolic volume (ESV). In ToF patients there was no correlation between PV loop parameters and peak VO2 even if correlation was found between peak VO2 and EDV or ESV. In conclusion, the LV seems to adapt its pumping according to anatomic circumstances without losing efficiency, however there are indications of persistent vascular dysfunction, expressed as high arterial elastance, which might have impact on exercise performance and prognosis. Future studies might elucidate if the duration of RV volume load and decreased LV filling have any impact on the ability of the vascular function to normalize after ASD closure or PVR.

Right ventricular longitudinal function is linked to left ventricular filling pressure in patients with repaired tetralogy of fallot

Experimental data on pulmonary regurgitation has linked right ventricular longitudinal function to left ventricular filling pressure in animals with induced and treated pulmonary regurgitation but this relationship has not been investigated in patients with repaired Tetralogy of Fallot (rToF). The aim of this study was to determine if right ventricular longitudinal function assessed using cardiovascular magnetic resonance (CMR) is associated with left ventricular filling pressure in patients with rToF. A second objective of this study was to determine if direction of septal movement is related to right ventricular pressure load in rToF. Eighteen patients with rToF undergoing CMR and heart catheterization prior to pulmonary valve replacement were retrospectively included and catheter-based pressure measurements were compared with CMR-derived RV regional function. Left ventricular filling pressure was measured as precapillary wedge pressure (PCWP). Longitudinal contribution to RV stroke volume correlated with PCWP (r = 0.48; p = 0.046) but not with RV EF or pulmonary regurgitation. Neither RV longitudinal strain nor TAPSE showed correlation with PCWP. Longitudinal contribution to stroke volume was lower for the RV compared to the LV (49 vs 54%; p = 0.039). Direction of septal movement did not show a correlation with RV end-systolic pressure. Right ventricular longitudinal pumping is associated with left ventricular filling pressure in rToF-patients and this inter-ventricular coupling may explain LV underfilling in patients with pulmonary regurgitation and rToF and may be of value to determine right ventricular dysfunction. RV systolic pressure, however, cannot be assessed from the direction of septal movement, in these patients.

Right ventricular functional recovery depends on timing of pulmonary valve replacement in tetralogy of Fallot: a video kinematic study

OBJECTIVES

Indications for and timing of pulmonary valve replacement (PVR) after tetralogy of Fallot repair are controversial. Among magnetic resonance imaging indices proposed to time valve replacement, a right ventricular (RV) end-diastolic volume index greater than 160 ml/m2 is often used. Recent evidence suggests that this value may still identify patients with irreversible RV dysfunction, thus hindering recovery. Our goal was to define, using intraoperative video kinematic evaluation, whether a relationship exists between timing of PVR and early functional recovery after surgery.

METHODS

Between November 2016 and November 2018, a total of 12 consecutive patients aged 27.1 ± 19.1 years underwent PVR on average 22.2 ± 13.3 years after tetralogy of Fallot repair. Mean RV end-diastolic volume evident on the magnetic resonance images was 136.9 ± 35.7 ml/m2. Intraoperative cardiac kinematics were assessed by video kinematic evaluation via a high-speed camera acquiring videos at 200 fps before and after valve replacement.

RESULTS

Patients presenting with RV end-diastolic volume <147 ml/m2 were significantly younger (11.2 ± 5.0 vs 38.4 ± 17.0; P = 0.005) and had a shorter time interval to valve replacement (11.0 ± 5.2 vs 30.1 ± 11.3; P = 0.03). The entire population showed a moderate correlation among energy expenditure, cardiac fatigue, perimeter of contraction and preoperative RV end-diastolic volume index. Both groups showed a reduction in all kinematic parameters after PVR, but those with end-diastolic volume >147 ml/m2 showed an unpredictable outcome.

CONCLUSIONS

Video kinematic evaluation provides insight into intraoperative RV recovery in patients with tetralogy of Fallot undergoing PVR. Accordingly, functional recovery can be expected in patients with preoperative end-diastolic volume <147 ml/m2.

The Prevalence and Independent Risk Factors of Significant Tricuspid Regurgitation Jets in Maintenance Hemodialysis Patients With ESRD

Background and Aim

Tricuspid regurgitation (TR) is a frequent complication in various cardiovascular diseases. However, few studies have reported the prevalence of TR especially the moderate to severe or significant TR (ms-TR) maintenance dialysis patients. Thus, we aimed to identify the prevalence of ms-TR and its associated factors.

Methods

A total of 491 maintenance dialysis patients underwent echocardiographic examinations, while a subgroup (n = 283) also received routine blood tests, renal function examinations, and electrolyte analysis. We first compared the differences in abovementioned parameters among groups with various TR areas (TRAs). Finally, univariate and adjusted regression were also used to identify factors that were independently associated with ms-TR.

Results

The incidence of TR jets was 62.6%, which included a mildly increased TRA (47.8%), moderately increased TRA (10.4%), and severely increased TRA (3.5%). Most of the cardiac structures and functional parameters, such as the end-diastolic internal diameters of the left atrium (LA), left ventricle (LVDD), right atrium (RA), right ventricle (RV), left ventricular ejection fraction (LVEF), and fractional shortening (FS), were significantly associated with ms-TR. Among serum ions, only total CO₂ (TCO₂; r = −0.141, p = 0.047) was negatively correlated with TRA. After adjusted, only Na⁺ [odds ratio (OR): 0.871 0.888, p = 0.048], RA (OR: 1.370, p < 0.001), and FS (OR: 0.887, p < 0.001) were independently associated with ms-TR.

Conclusion

Tricuspid regurgitation occurs in maintenance hemodialysis patients with ESRD. Na⁺ FS and RA were independently associated with ms-TR, and these parameters may be potential risk factors/predictors for ms-TR.

Changes in left and right ventricular longitudinal function after pulmonary valve replacement in patients with Tetralogy of Fallot

Timing and indication for pulmonary valve replacement (PVR) in patients with repaired Tetralogy of Fallot (rToF) and pulmonary regurgitation (PR) are uncertain. To improve understanding of pumping mechanics, we investigated atrioventricular coupling before and after surgical PVR. Cardiovascular magnetic resonance was performed in patients (n = 12) with rToF and PR > 35% before and after PVR and in healthy controls (n = 15). Atrioventricular plane displacement (AVPD), global longitudinal peak systolic strain (GLS), atrial and ventricular volumes, and caval blood flows were analyzed. Right ventricular (RV) AVPD and RV free wall GLS were lower in patients before PVR compared with controls (P < 0.0001; P < 0.01) and decreased after PVR (P < 0.0001 for both). Left ventricular AVPD was lower in patients before PVR compared with controls (P < 0.05) and decreased after PVR (P < 0.01). Left ventricular GLS did not differ between patients and controls (P > 0.05). Right atrial reservoir volume and RV stroke volume generated by AVPD correlated in controls (r = 0.93; P < 0.0001) and patients before PVR (r = 0.88; P < 0.001) but not after PVR. In conclusion, there is a clear atrioventricular coupling in patients before PVR that is lost after PVR, possibly because of loss of pericardial integrity. Impaired atrioventricular coupling complicates assessment of ventricular function after surgery using measurements of longitudinal function. Changes in atrioventricular coupling seen in patients with rToF may be energetically unfavorable, and long-term effects of surgery on atrioventricular coupling is therefore of interest. Also, AVPD and GLS cannot be used interchangeably to assess longitudinal function in rToF.NEW & NOTEWORTHY There is a clear atrioventricular coupling in patients with Tetralogy of Fallot (ToF) and pulmonary regurgitation before surgical pulmonary valve replacement (PVR) that is lost after operation, possibly because of loss of pericardial integrity. The impaired atrioventricular coupling complicates assessment of ventricular function after surgery when using measurements of longitudinal function. Left ventricular atrioventricular plane displacement (AVPD) found differences between patients and controls and changes after PVR that longitudinal strain could not detect. This indicates that AVPD and strain cannot be used interchangeably to assess longitudinal function in repaired ToF.

Animal Models of Repaired Tetralogy of Fallot: Current Applications and Future Perspectives

Tetralogy of Fallot is the most common cyanotic congenital heart disease. Despite ongoing improvements in the initial surgical repair, there are lingering concerns regarding the long-term outcomes that may be complicated by right ventricular dysfunction, right ventricular dyssynchrony, and sudden cardiac death. The mechanisms leading to these late complications remain incompletely understood. Experimental animal models have been developed as preclinical steps to gain better insight into the pathophysiology of diseases and to develop new therapeutic strategies. This article summarizes the various types of experimental animal models of repaired tetralogy of Fallot published to date in the literature, with the aim of achieving a greater understanding of the deleterious mechanisms that may lead to these known late and sometimes lethal complications. In addition to analysing the type of animals that can be used according to a given study's objectives, needs, and constraints, the present review also evaluates the type of dysfunction that can be reproduced in our model according to the research objectives, as well as the different types of studies in which these models can be used. In view of all that, we propose a decision algorithm to create an animal model of repaired tetralogy of Fallot. This synthesis should furthermore help in the development of future studies and in the design of new experimental models, thus allowing greater insight into this disease, while not forgetting the ultimate goal of broadening future therapeutic measures to reduce the morbidity and mortality of this prevalent congenital heart disease.

Increased right atrial volume measured with cardiac magnetic resonance is associated with worse clinical outcome in patients with pre-capillary pulmonary hypertension

AIMS

Pre-capillary pulmonary hypertension (PHpre-cap ) has a poor prognosis, especially when caused by pulmonary arterial hypertension (PAH) associated with systemic sclerosis (SSc-PAH). Whether cardiac magnetic resonance (CMR)-based quantification of atrial volumes in PHpre-cap is beneficial in risk assessment is unknown. The aims were to investigate if (i) atrial volumes using CMR are associated with death or lung transplantation in PHpre-cap , (ii) atrial volumes differ among four unmatched major PHpre-cap subgroups, and (iii) atrial volumes differ between SSc-PAH and idiopathic/familial PAH (IPAH/FPAH) when matched for pulmonary vascular resistance (PVR).

METHODS AND RESULTS

Seventy-five PHpre-cap patients (57 ± 19 years, 53 female, 43 de novo) with CMR and right heart catheterization were retrospectively included. Short-axis stacks of cine images were analysed, and right and left atrial maximum (RAVmax and LAVmax ) and minimum volume (RAVmin and LAVmin ) were indexed for body surface area. Increased (mean + 2 SD) and reduced (mean - 2 SD) volumes were predefined from CMR normal values. Transplantation-free survival was lower in patients with increased RAVmax than in those with normal [hazard ratio (HR) = 2.1, 95% confidence interval (CI) 1.1-4.0] but did not differ between those with reduced LAVmax and normal (HR 2.0, 95% CI 0.8-5.1). RAVmax and RAVmin showed no differences among unmatched or matched groups (P = ns). When matched for PVR, LAVmax , LAVmin , and pulmonary artery wedge pressure were reduced in SSc-PAH compared with IPAH/FPAH (95% CI 0.3-21.4, 95% CI 0.8-19.6, and 95% CI 2-7, respectively).

CONCLUSIONS

Patients with PHpre-cap and increased right atrial volume measured with CMR had worse clinical outcome. When matched for PVR, left atrial volume was lower in SSc-PAH than in IPAH/FPAH, consistent with left-sided underfilling, indicating a potential differentiator between the groups.

Altered biventricular hemodynamic forces in patients with repaired tetralogy of Fallot and right ventricular volume overload because of pulmonary regurgitation

Intracardiac hemodynamic forces have been proposed to influence remodeling and be a marker of ventricular dysfunction. We aimed to quantify the hemodynamic forces in patients with repaired tetralogy of Fallot (rToF) to further understand the pathophysiological mechanisms as this could be a potential marker for pulmonary valve replacement (PVR) in these patients. Patients with rToF and pulmonary regurgitation (PR) > 20% ( n = 18) and healthy control subjects ( n = 15) underwent MRI, including four-dimensional flow. A subset of patients ( n = 8) underwent PVR and MRI after surgery. Time-resolved hemodynamic forces were quantified using 4D-flow data and indexed to ventricular volume. Patients had higher systolic and diastolic left ventricular (LV) hemodynamic forces compared with control subjects in the lateral-septal/LV outflow tract ( P = 0.011 and P = 0.0031) and inferior-anterior ( P < 0.0001 and P < 0.0001) directions, which are forces not aligned with blood flow. Forces did not change after PVR. Patients had higher RV diastolic forces compared with control subjects in the diaphragm-right ventricular (RV) outflow tract (RVOT; P < 0.001) and apical-basal ( P = 0.0017) directions. After PVR, RV systolic forces in the diaphragm-RVOT direction decreased ( P = 0.039) to lower levels than in control subjects ( P = 0.0064). RV diastolic forces decreased in all directions ( P = 0.0078, P = 0.0078, and P = 0.039) but were still higher than in control subjects in the diaphragm-RVOT direction ( P = 0.046). In conclusion, patients with rToF and PR had LV hemodynamic forces less aligned with intraventricular blood flow compared with control subjects and higher diastolic RV forces along the regurgitant flow direction in the RVOT and that of tricuspid inflow. Remaining force differences in the LV and RV after PVR suggest that biventricular pumping does not normalize after surgery. NEW & NOTEWORTHY Biventricular hemodynamic forces in patients with repaired tetralogy of Fallot and pulmonary regurgitation were quantified for the first time. Left ventricular hemodynamic forces were less aligned to the main blood flow direction in patients compared with control subjects. Higher right ventricular forces were seen along the pulmonary regurgitant and tricuspid inflow directions. Differences in forces versus control subjects remain after pulmonary valve replacement, suggesting that altered biventricular pumping does not normalize after surgery.

Disturbed left and right ventricular kinetic energy in patients with repaired tetralogy of Fallot: pathophysiological insights using 4D-flow MRI

OBJECTIVES

Indications for pulmonary valve replacement (PVR) in patients with pulmonary regurgitation (PR) after repaired tetralogy of Fallot (rToF) are debated. We aimed to compare right (RV) and left ventricular (LV) kinetic energy (KE) measured by 4D-flow magnetic resonance imaging (MRI) in patients to controls, to further understand the pathophysiological effects of PR.

METHODS

Fifteen patients with rToF with PR > 20% and 14 controls underwent MRI. Ventricular volumes and KE were quantified from cine MRI and 4D-flow, respectively. Lagrangian coherent structures were used to discriminate KE in the PR. Restrictive RV physiology was defined as end-diastolic forward flow.

RESULTS

LV systolic peak KE was lower in rToF, 2.8 ± 1.1 mJ, compared to healthy volunteers, 4.8 ± 1.1 mJ, p < 0.0001. RV diastolic peak KE was higher in rToF (7.7 ± 4.3 mJ vs 3.1 ± 1.3 mJ, p = 0.0001) and the difference most pronounced in patients with non-restrictive RV physiology. KE was primarily located in the PR volume at the time of diastolic peak KE, 64 ± 17%.

CONCLUSION

This is the first study showing disturbed KE in patients with rToF and PR, in both the RV and LV. The role of KE as a potential early marker of ventricular dysfunction to guide intervention needs to be addressed in future studies.

KEY POINTS

• Kinetic energy (KE) reflects ventricular performance • KE is a potential marker of ventricular dysfunction in Fallot patients • KE is disturbed in both ventricles in patients with tetralogy of Fallot • KE contributes to the understanding of the pathophysiology of pulmonary regurgitation • Lagrangian coherent structures enable differentiation of ventricular inflows.

Alterations in ventricular pumping in patients with atrial septal defect at rest, during dobutamine stress and after defect closure

BACKGROUND

Regional ventricular pumping mechanisms in patients with volume-loaded right ventricles (RV) are altered, but the cause is unknown. The aim was to determine whether these changes in ventricular pumping mechanisms are influenced by the RV dilatation itself or the aetiology behind it.

METHODS

Seventeen patients with atrial septal defects (ASD) and 10 healthy controls underwent cardiovascular magnetic resonance (CMR) at rest and during dobutamine/atropine stress. Sixteen patients underwent transcutaneous ASD closure. Follow-up CMR at rest was performed the following day. Thirty patients with RV overload due to pulmonary regurgitation (PR) underwent CMR at rest. Cine images were used to measure left ventricular (LV) and RV volumes as well as septal, longitudinal and lateral contributions to LV and RV stroke volume (SV).

RESULTS

At rest, septal contribution to LVSV was lower in ASD patients than controls (-1% versus 7%, P<0·05), but there was no difference in longitudinal or lateral contribution to SV. Patients with PR had lower longitudinal contribution to RV with increased lateral and septal contribution. During dobutamine stress, longitudinal contribution to LV and RVSV decreased and lateral contribution increased for ASD patients and controls. The day after ASD closure, septal contribution to LVSV was 6%, longitudinal contribution had increased for RVSV (P<0·05) and decreased for LVSV (P<0·01).

CONCLUSION

Pumping mechanisms in patients with RV volume overload depend on the aetiology for the RV dilation and not the size of the RV.

Longitudinal shortening remains the principal component of left ventricular pumping in patients with chronic myocardial infarction even when the absolute atrioventricular plane displacement is decreased

Background

The majority (60%) of left ventricular (LV) stroke volume (SV) is generated by longitudinal shortening causing apical atrioventricular plane displacement (AVPD) in systole. The remaining SV is caused by radial inward motion of the epicardium both in the septal and the lateral wall. We aimed to determine if these longitudinal, septal and lateral contributions to LVSV are changed in patients with chronic myocardial infarction (MI).

Methods

Patients with a chronic (>3 months) ST-elevation MI in the left anterior descending (LAD, n = 20) or right coronary artery (RCA, n = 16) and healthy controls (n = 20) were examined with cardiovascular magnetic resonance (CMR). AVPD was quantified in long axis cine CMR images and LV volumes and dimensions in short axis cine images.

Results

AVPD was decreased both in patients with LAD-MI (11 ± 1 mm, p < 0.001) and RCA-MI (13 ± 1 mm, p < 0.05) compared to controls (15 ± 0 mm). However, the longitudinal contribution to SV was unchanged for both LAD-MI (58 ± 3%, p = 0.08) and RCA-MI (59 ± 3%, p = 0.09) compared to controls (64 ± 2%). The preserved longitudinal contribution despite decreased absolute AVPD was a results of increased epicardial dimensions (p < 0.01 for LAD-MI and p = 0.06 for RCA-MI). In LAD-MI the septal contribution to LVSV was decreased (5 ± 1%) compared to both controls (10 ± 1%, p < 0.01) and patients with RCA-MIs (10 ± 1%, p < 0.01). The lateral contribution was increased in LAD-MI patients (44 ± 3%) compared to both RCA-MI (35 ± 2%, p < 0.05) and controls (29 ± 2%, p < 0.001).

Conclusion

Longitudinal shortening remains the principal component of left ventricular pumping in patients with chronic MI even when the absolute AVPD is decreased.