Adult Congenital Heart Disease

Left Valvar Morphology is Associated with Late Regurgitation in Atrioventricular Canal Defect Ho DY, Katcoff H, Griffis HM, Mercer-Rosa L, Fuller SM, Cohen MS. Ann Thorac Surg. 2020 Feb 20. pii: S0003-4975(20)30219-8. doi: 10.1016/j.athoracsur.2020.01.012. [Epub ahead of print] PMID: 32088289 Similar articles Select item 32079620   Take Home Points: Residual left atrioventricular valve regurgitation (LAVVR) is commonly seen after surgery. Complex leaflet morphology, which results in complex valve repair is associated with early LAVVR. However, after controlling the weight at surgery, presence of genetic syndrome and bypass time, multivariate analysis showed presence of widely spaced papillary muscles and larger mural leaflet area were associated with late LAVVR. There may be other pathology, other than the progression of LAVVR which is responsible for late onset LAVVR.   Commentary from Dr. M.C. Leong (Kuala Lumpur, Indonesia), section editor of ACHD Journal Watch: Left atrioventricular valve regurgitation (LAVVR) following repair of atrioventricular canal repair is not uncommon and it causes significant morbidity. The authors sought to characterise the left mural leaflet and papillary muscle morphology in patients with atrioventricular canal defects to determine if variation in leaflet anatomy were risk factors for postoperative LAVVR.   This is single-centre, retrospective review of all patients with complete or transitional atrioventricular canal who underwent repair from January 2011 until December 2016. During this period, 156 patients, of whom 84% had complete atrioventricular septal defect were included (Table 1). Majority of these patients underwent repair using a two-patch technique and cleft closure. Of these patients, 58 (37%) patients had significant early postoperative LAVVR. 16 (10%) patients underwent left atrioventricular valve reoperation or replacement. In 11 of these patients, reoperation occurred within the first 3 months. Four patients required two or more reoperation and of these, 3 eventually underwent mechanical valve replacement. In the long term, 30 of 93 (32%) had significant LAVVR (Figure 3).     Longer bypass time, deep hypothermia circulatory arrest, and repeat bypass runs were associated with early postoperative LAVVR but not late LAVVR (Table 5). This underscored the surgical complexity as the cause for early postoperative LAVVR. However, late LAVVR was associated with papillary morphology. The authors characterised the morphology into (a) widely spaced papillary muscle, (b) closely spaced papillary muscles, (c) Dominant papillary muscle, (d) mural leaflet area : overall left atrioventricular valve area and cleft length: overall left atrioventricular valve diameter (Figure 2). They noted that after controlling the weight at surgery, presence of genetic syndrome and bypass time, multivariate analysis showed presence of widely spaced papillary muscles and larger mural leaflet area were associated with late LAVVR (Table 6).         The results of the study came as a surprise for a few reasons. Firstly, patients with complex valve morphology was associated with early but not late LAVVR suggesting that late AVVR may not be a progression of the early LAVVR. Secondly, patients with widely spaced papillary muscles usually has a larger mural leaflet area which generally confer less atrioventricular valve regurgitation post-operatively but has been shown to be associated to late LAVVR, which suggest other pathology being the cause the late LAVVR. Unfortunately, the study was not powered to assess these causes of the late LAVVR.    

Pulmonary artery size is associated with functional clinical status in the Fontan circulation Ridderbos FS, Bonenkamp BE, Meyer SL, Eshuis G, Ebels T, van Melle JP, Willems TP, Berger RMF. Heart. 2020 Feb;106(3):233-239. doi: 10.1136/heartjnl-2019-314972. Epub 2019 Sep 6. PMID: 31492699 Similar articles Select item 30826267   Take Home Points: The Nakata index = (left pulmonary artery cross sectional area + right pulmonary artery cross sectional area) by body surface area (mm2/m2). Single centre study of 39 (child and adult) patients with a Fontan circulation – mean age at time of CMR study 18 ±7 yrs. Cross sectional, single centre study of patients with a Fontan circulation exploring whether the Nakata index is associated with longer term functional clinical status – subjective and objective. The Nakata index in patients with a Fontan was significantly smaller compared to normal control subjects (n=40) – 239±79 mm2/m2 vs 330±30mm2/m2 (p<0.001). Nakata index was positively correlated to higher peak VO2. Nakata index was negatively correlated to NYHA functional class. Nakata index was an independent predictor of peak VO2. Patients with a Fontan circulation and higher Nakata index have a higher peak VO2 and are subjectively less breathless compared to similar patients with a smaller Nakata index.   Commentary from Dr. Damien Cullington (Liverpool, UK), section editor of ACHD Journal Watch: The Fontan circulation is a palliative procedure with no shortage of long-term problems. We are continually striving to understand in more detail what constitutes the ‘good Fontan’ – good ventricular function, a predominantly systemic LV, no significant valvular dysfunction and an unobstructed Fontan pathway are four key elements.   It seems relatively intuitive that patients with a Fontan circulation and larger pulmonary arteries (PAs) would be a ‘better Fontan’ compared to patients with relatively smaller PAs. This analysis from Ridderbos et al sought to investigate whether relative PA size post Fontan completion correlates to longer term subjectively reported symptoms (NYHA) and objective measurement of functional capacity (peak VO2). The authors state that no CMR based study has assessed this relationship previously. The primary end points to assess subjective and objective clinical status were NYHA class and the standard cardiopulmonary measure of peak VO2 respectively. The authors nicely illustrate the comparative difference in PA size (measured by Nakata index) in patients with a Fontan compared to the Nakata indices of normal subjects (Figure 1).   The baseline characteristics of the cohort are shown in Table 1. The mean age of patients was 18±7 yrs., 98% of the cohort had a lateral tunnel or extra-cardiac conduit type Fontan and 82% had a systemic left ventricle. This was a mixed cohort of paediatric and adult patients – the majority of patients were <20 years old with a mean duration between Fontan completion and CMR of 12 ±7 years.     Correlation between Nakata Index, baseline characteristics and functional status   Nakata index correlated negatively with age at CMR (r= -0.39, p=0.013) and time since Fontan completion (r = -0.34, p=0.034). Patients with an extracardiac conduit had a significantly higher Nakata index (p=0.03) compared to those with a lateral tunnel (269 ± 90 mm2/m2 vs 214 ± 57 mm2/m2).   The Nakata index was negatively correlated with NYHA class (Figure 2) and positively correlated with peak VO2 (indexed for weight and % of predicted peak VO2) (Figure 3). The Nakata index was a significant univariable predictor of peak VO2 and remained so in a multivariable model incorporating maximum heart rate and O2 pulse at peak exercise.   Patients with previous central PA banding (n=13) or a systemic-to-PA shunt (n=15) had smaller Nakata indices than patients who had not had such interventions (p=0.045).   Based on these results, what can we do better?   This study found that patients with a Fontan circulation who have a higher Nakata index, therefore, larger PAs, have higher functional capacity (measured by peak VO2) and lower self-reported NYHA class.   So, what can the congenital cardiology team do to help achieve better long-term functional outcomes for our Fontan patients? It is clear that some factors are easily modifiable, others not so. There may be some signal to suggest an extracardiac conduit is associated with a higher Nakata index and PAs are larger in patients who avoid PA banding or BT shunts, but naturally, some surgical interventions are a necessity. Pulmonary distensibility is an important component of functional capacity so meticulous surgical technique throughout the palliative pathway is required to avoid PA injury/scar and achieve high quality Fontan conduit anastomoses.   Patients with a Fontan circulation, compared to normal subjects have a significantly smaller pulmonary artery cross sectional area. This is probably to be due to an attenuation of growth of the pulmonary vasculature due to, atypical, non-pulsatile flow through the pulmonary arteries. Further, sequential analyses need to be performed to understand how PA size (and therefore the Nakata index) changes as patients age. This is now easily achievable since most patients with a Fontan have cross sectional imaging repeated as part of a standard protocol every 3-5 years. Repeated cross sectional imaging will help to serially reappraise whether proactive catheter interventions are required to help optimise Fontan flow. Application of 4D flow analysis may also be ancillary to decision making.    

Septal Flash-like Motion of the Earlier Activated Ventricular Wall Represents the Pathophysiology of Mechanical Dyssynchrony in Single-Ventricle Anatomy Hayama Y, Miyazaki A, Ohuchi H, Miike H, Negishi J, Sakaguchi H, Kurosaki K, Shimizu S, Kawada T, Sugimachi M. J Am Soc Echocardiogr. 2020 Feb 20. pii: S0894-7317(19)31183-6. doi: 10.1016/j.echo.2019.11.016. [Epub ahead of print] PMID: 32089381 Similar articles Select item 30422578   Take Home Point: In patients with single ventricle physiology and a prolonged QRS, early shortening and paradoxical post systolic stretch are associated with poorer clinical state according to greater BNP and reduced peak VO2. Commentary from Dr. Helen Parry (Leeds UK), section editor of ACHD Journal Watch:   Aim: To assess whether dyssynchrony of contraction has clinical consequences in univentricular hearts   Methods: Inclusion criteria: Post op Glenn or Fontan Prolonged QRS defined as z score >=2 in patients under 18 or >120ms in patients 18 or over Regular R-R interval Good echo windows Patients fulfilling these criteria had echocardiography with strain, focusing on the apical view that included the aorta, the free wall of the dominant/ apex forming ventricle and its opposite wall/ septal remnant.   AV valve and aortic valve opening and closure times were assessed using pulsed wave Doppler. Strain studies (GLS) were then performed on the 2 walls as divided above.   Strain ratio (Rs) was used to quantify early shortening followed by post systolic paradoxical stretch - Rs= (100+ GLS at aortic valve closure)/(100+ GLS at aortic valve opening)   BNP was measured in all patients and exercise testing was undertaken where possible to allow comparison between degree of dyssynchrony and clinical status.   6 patients underwent CRT for heart failure symptoms refractory to medical management   Results: 70 patients were enrolled. 25 were female.   Time to peak strain of the earlier activated wall was associated with BNP levels (p<0.001). Strain ratio was associated with both BNP and peak VO2 (p<0.001 for both). There were no statistically significant associations between BNP and peak VO2 and either time to peak strain or strain ratio of the later activated wall.   Patients who underwent CRT had improvement in dyssynchrony quantified by improved strain ratio as above.   Discussion: The authors conclude that early shortening and paradoxical post systolic stretch are associated with poorer clinical state according to greater BNP and reduced peak VO2.   Strengths of the study: Novel Clear strategy for assessment of dyssynchrony in single ventricle physiology outlined Pathophysiology seems logical Weaknesses: The number of patients undergoing CRT was too small to draw any conclusion Single centre study GLS on Phillips machine- specific to this machine and cannot be compared with other manufacturers Many patients with single ventricle physiology do not have good enough transthoracic windows for strain