Relation of aortic stiffness and strain by cardiovascular magnetic resonance imaging to age in repaired tetralogy of fallot

Myocardial, Valvular and Vascular Abnormalities in Repaired Tetralogy of Fallot

Tetralogy of Fallot is the most common heart defect associated with cyanosis characterized by the co-occurrence of pulmonary stenosis, right ventricular hypertrophy, and ventricular septal defect with over-riding of the aorta. The present review purposed to summarize myocardial, valvular and vascular abnormalities, which were described in a series of patients following repair of tetralogy of Fallot. It was also aimed to describe potential differences in these parameter using different surgical strategies.

The association between cardiac magnetic resonance-derived aortic stiffness parameters and aortic dilation in young adults with bicuspid aortic valve: With and without coarctation of aorta

Background

Bicuspid aortic valve (BAV) is associated with progressive aortic dilation. Studies in aortopathies have shown a correlation between increased aortic stiffness and aortic dilation. We aimed to evaluate aortic stiffness measures as predictors of progressive aortic dilation by cardiac magnetic resonance (CMR) in BAV patients.

Methods

This is a retrospective study of 49 patients with BAV (median age 21.1 years at first CMR visit) with ≥2 CMR at the Wisconsin Adult Congenital Heart Disease Program (WAtCH). Circumferential aortic strain, distensibility, and β-stiffness index were obtained from CMR-derived aortic root cine imaging, and aortic dimensions were measured at aortic root and ascending aorta. A linear mixed-model and logistic regression were used to identify important predictors of progressive aortic dilation.

Results

Over a median of 3.8 years follow-up, the annual growth rates of aortic root and ascending aorta dimensions were 0.25 and 0.16 mm/year, respectively. Aortic strain and distensibility decreased while β-stiffness index increased with age. Aortic root strain and distensibility were associated with progressive dilation of the ascending aorta. Baseline aortic root diameter was an independent predictor of >1 mm/year growth rate of the aortic root (adjusted OR 1.34, 95 % CI 1.03-1.74, p = 0.028). Most patients (61 %) had coexisting coarctation of aorta. Despite the higher prevalence of hypertension in patients with aortic coarctation, hypertension or coarctation had no effect on baseline aorta dimensions, stiffness, or progressive aortic dilation.

Conclusion

Some CMR-derived aortic stiffness parameters correlated with progressive aortic dilation in BAV and should be further investigated in larger and older BAV cohorts.

Magnetic resonance imaging assessment of aortic dilatation and distensibility in 269 patients with repaired tetralogy of Fallot

PURPOSE

To determine the prevalence and degree of aortic dilatation (A_dilatation), severity of aortic stiffness (A_stiff), factors for A_dilatation, and level of aortic root most sensitive to A_stiff in patients with repaired tetralogy of Fallot (rTOF).

MATERIALS AND METHODS

269 patients with rTOF (mean age 14.9 ± standard deviation 5.0 years) were analyzed for A_dilatation at annulus, sinus, sinotubular junction, and ascending aorta (aAo). Aortic size index was graded as Z score < 2, 2-2.99, 3-4.99 and ≥ 5. Aortic distensibility (aA_dis) was categorized according to 4 aortic levels and dilatation severity. Factors for A_dilatation and level of aortic root most sensitive to A_stiff were analyzed.

RESULTS

Sinus and aAo were the two most common sites of A_dilatation, with a prevalence of 84% and 76%, respectively. A decreased aA_dis was found (mean 5.38 ± 1.79 10^-3 mmHg^-1). aA_dis only declined significantly at the sinus level (p = 0.009). Male sex, age-at-repair and aortic regurgitation were significant factors for A_dilatation, with male sex as the strongest factor (odds ratio 2.94). There was a significant decline in aA_dis at sinus level (p = 0.002) as A_dilatation progressed.

CONCLUSIONS

We observed a high prevalence of A_dilatation and A_stiff in patients with rTOF. Male sex is the strongest factor for A_dilatation. The sinus is the most sensitive area for determining a negative aA_dis effect.

Aortopathy in Congenital Heart Disease

Aortic dilatation is common in patients with congenital heart disease and is seen in patients with bicuspid aortic valve and those with conotruncal congenital heart defects. It is important to identify patients with bicuspid aortic valve at high risk for aortic dissection. High-risk patients include those with the aortic root phenotype and those with syndromic or familial aortopathies including Marfan syndrome, Loeys-Dietz syndrome, and Turner syndrome. Aortic dilatation is common in patients with conotruncal congenital heart defects and rarely results in aortic dissection.

Aortopathy in tetralogy of Fallot-a collective review

The pathophysiology of aortic diseases in Tetralogy of Fallot has been analyzed in various studies, focusing on the histopathology of the aortic root, altered hemodynamics, and effect of early corrective repair on the incidence of aortic root dilatation. In this review article, we sought to integrate these studies for a better understanding of the natural history and practical implications of aortic root dilatation in Tetralogy of Fallot. This better equips us to appropriately implement potentially effective interventions.

Implication of Aortic Root Dilation and Stiffening in Patients with Tetralogy of Fallot

Progressive aortic root dilation and stiffening have been reported in patients with tetralogy of Fallot (TOF), even after repair. However, the implications of such aortic dilation and stiffening have not been fully assessed. A stiff aorta has a negative effect on the coronary circulation. 15 patients with TOF after repair were enrolled in this study. Using a left ventriculogram and pressure waveform recorded by a pressure sensor-mounted catheter, we analyzed the diameter and distensibility of the ascending and descending aorta. We also calculated the subendocardial viability ratio (SEVR), which measures the cardiac blood supply-workload balance. These values were compared with those in one-to-one age-matched controls. Moreover, the correlation between the diameter ratio (aortic diameter of the patient/aortic diameter of the matched control subject) and the distensibility ratio (distensibility of the patient/distensibility of the matched control subject) was analyzed. The mean age of patients was 3.9 ± 1.6 years. In patients with TOF, the indexed diameter was larger (0.20 ± 0.02 vs. 0.15 ± 0.02 mm/cm, p < 0.0001) and the distensibility was lower (5.1 ± 2.2 vs. 7.7 ± 2.0 cm² dynes^-1 10^-6, p = 0.0009) in the ascending aorta than in control subjects. There was no difference in the SEVR between patients and control subjects. The distensibility ratio was significantly negatively correlated with the indexed diameter ratio in the ascending aorta (r² = 0.35, p = 0.019). Regardless of the aortic stiffening, the cardiac blood supply-workload balance was maintained. We speculate that the aortic root dilation might be a mechanism to functionally complement aortic stiffness in patients with TOF.

Strain of ascending aorta on cardiac magnetic resonance in 1027 patients: Relation with age, gender, and cardiovascular disease

OBJECTIVES

To evaluate ascending aortic strain (AAS) with cardiac magnetic resonance (CMR) in a large consecutive series of patients with different types of cardiovascular disease (CVD).

METHODS

Two-dimensional phase-contrast gradient-echo sequences of the ascending aorta were retrospectively reviewed in 1027 patients (726 males, 301 females). Aortic lumen area was segmented using a semi-automatic approach to calculate AAS values. Subgroup analysis was performed for patients with normal CMR, tetralogy of Fallot (ToF), and ischemic heart disease (IHD). Multivariate and post-hoc analyses were performed to evaluate the effect of age, gender, and CVD on AAS values. Shapiro-Wilk, three- and two-way ANOVA, Mann-Whitney U, and Spearman correlation statistics were used.

RESULTS

Multivariate analysis showed significant differences in AAS among decades of age (p<0.001), genders (p=0.006) and CVD subgroups (p<0.001) without interaction among these factors. A gender-related difference (higher AAS in females) was significant in ToF (p=0.008), while an AAS reduction during aging was observed in all CVD subgroups. Post-hoc analysis showed a significantly lower AAS in ToF and IHD patients compared to subjects with normal CMR (p<0.001).

CONCLUSION

Differences in age, gender, and CVD independently affect AAS. The lower AAS observed in ToF fosters its assessment during follow-up in adulthood. Future studies on causes and clinical implications of a higher AAS in females affected by ToF are warranted.