Prognostic significance of myocardial fibrosis and CMR characteristics in bicuspid aortic valve with moderate and severe aortic insufficiency

Flow quantification within the aortic ejection tract using 4D flow cardiac MRI in patients with bicuspid aortic valve: Implications for the assessment of aortic regurgitation

PURPOSE

The purpose of this study was to evaluate the performance of four-dimensional (4D) flow cardiac MRI in quantifying aortic flow in patients with bicuspid aortic valve (BAV).

MATERIALS AND METHODS

Patients with BAV who underwent transthoracic echocardiography (TTE) and 4D flow cardiac MRI were prospectively included. Aortic flow was quantified using two-dimensional phase contrast velocimetry at the sinotubular junction and in the ascending aorta and using 4D flow in the regurgitant jet, in the left ventricular outflow tract, at the aortic annulus, the sinotubular junction, and the ascending aorta, with or without anatomical tracking. Flow quantification was compared with ventricular volumes, pulmonary flow using Pearson correlation test, bias and limits of agreement (LOA) using Bland Altman method, and with multiparametric transthoracic echocardiography quantification using weighted kappa test.

RESULTS

Eighty-eight patients (63 men, 25 women) with a mean age of 50.5 ± 14.8 (standard deviation) years (age range: 20.8-78.3) were included. Changes in flow with or without tracking were modest (< 5 mL). The best correlation was obtained at the aortic annulus for forward volume (r = 0.84; LOA [-28.4; 25.3] mL) and at the regurgitant jet and sinotubular junction for regurgitant volume (r = 0.68; LOA [-27.8; 33.8] and r = 0.69; LOA [-28.6; 24.2] mL). A combined approach for regurgitant fraction and net volume calculations using forward volume measured at ANN and regurgitant volume at sinotubular junction performed better than each level taken separately (r = 0.90; LOA [-20.7; 10.0] mL and r = 0.48, LOA [-33.8; 33.4] %). The agreement between transthoracic echocardiography and 4D flow cardiac MRI for aortic regurgitation grading was poor (kappa, 0.13 to 0.42).

CONCLUSION

In patients with BAV, aortic flow quantification by 4D flow cardiac MRI is the most accurate at the annulus for the forward volume, and at the sinotubular junction or directly in the jet for the regurgitant volume.

Left ventricular reverse remodeling after aortic valve replacement or repair in bicuspid aortic valve with moderate or greater aortic regurgitation

Objective

Bicuspid aortic valve (AV) patients with aortic regurgitation (AR) differ from tricuspid AV patients given younger age, greater left ventricle (LV) compliance, and more prevalent aortic stenosis (AS). Bicuspid AV-specific data to guide timing of AV replacement or repair are lacking.

Methods

Adults with bicuspid AV and moderate or greater AR who underwent aortic valve replacement or repair at our center were studied. The presurgical echocardiogram, and echocardiograms within 3 years postoperatively were evaluated for LV geometry/function, and AV function. Semiquantitative AS/AR assessment was performed in all patients with adequate imaging.

Results

One hundred thirty-five patients (85% men, aged 44.5 ± 15.9 years) were studied (63% pure AR, 37% mixed AS/AR). Following aortic valve replacement or repair, change in LV end-diastolic dimension and change in LV end-diastolic volume were associated with preoperative LV end-diastolic dimension (β = 0.62 Δcm/cm; 95% CI, 0.43-0.73 Δcm/cm; P < .001), and LV end-diastolic volume (β = 0.6 ΔmL/mL; 95% CI, 0.4-0.7 ΔmL/mL; P < .001), respectively, each independent of AR/AS severity (P = not significant). Baseline LV size predicted postoperative normalization (LV end-diastolic dimension: odds ratio, 3.75/cm; 95% CI, 1.61-8.75/cm, LV end-diastolic volume: odds ratio, 1.01/mL; 95% CI, 1.004-1.019/mL, both P values < .01) whereas AR/AS severity did not (P = not significant). Indexed LV end diastolic volume outperformed LV end-diastolic dimension in predicting postoperative LV normalization (area under the curve = 0.74 vs 0.61) with optimal diagnostic cutoffs of 99 mL/m2 and 6.1 cm, respectively. Postoperative indexed LV end diastolic volume dilatation was associated with increased risk of death, transplant/ventricular assist device, ventricular arrhythmia, and reoperation (hazard ratio, 6.1; 95% CI, 1.7-21.5; P < .01).

Conclusions

Remodeling extent following surgery in patients with bicuspid AV and AR relates to preoperative LV size independent of valve disease phenotype or severity. Many patients with LV end-diastolic dimension below current surgical thresholds did not normalize LV size. LV volumetric assessment offered superior diagnostic performance for predicting residual LV dilatation, and postoperative indexed LV end diastolic volume dilatation was associated with adverse prognosis.

The Role of Genetic Testing in Patients with Heritable Thoracic Aortic Diseases

Heritable thoracic aortic disease (HTAD) is a term used to define a large group of disorders characterized by the occurrence of aortic events, mainly represented by aneurysm or dissection. These events generally involve the ascending aorta, although the involvement of other districts of the aorta or peripheral vessels may occur. HTAD can be classified as non-syndromic if the disorder is limited to the aorta, and syndromic when associated with extra-aortic features. About 20-25% of patients with non-syndromic HTAD exhibit a family history of aortic disease. Thus, a careful clinical evaluation of the proband and the first-degree family members is required to differentiate familial and sporadic cases. Genetic testing is essential since it allows confirmation of the etiological diagnosis of HTAD (particularly in patients with a significant family history) and may guide family screening. In addition, genetic diagnosis significantly impacts patients' management since the different conditions significantly differ with respect to natural history and treatment strategies. The prognosis in all HTADs is determined by the progressive dilation of the aorta, potentially leading to acute aortic events, such as dissection or rupture. Moreover, the prognosis varies according to the underlying genetic mutations. This review aims to describe the clinical characteristics and natural history of the most common HTADs, with particular emphasis on the role of genetic testing in risk stratification and management.

The Chinese Experience of Imaging in Cardiac Intervention: A Bird's Eye Review

Recent scientific and technological advances have greatly contributed to the development of medical imaging that could enable specific functions. It has become the primary focus of cardiac intervention in preoperative assessment, intraoperative guidance, and postoperative follow-up. This review provides a contemporary overview of the Chinese experience of imaging in cardiac intervention in recent years.

Reduced myocardial septal function assessed by cardiac magnetic resonance feature tracking in patients with hypertrophic obstructive cardiomyopathy: associated with histological myocardial fibrosis and ventricular arrhythmias

AIMS

Echocardiographic studies suggest that strain is related to myocardial fibrosis (MF) and ventricular arrhythmias (VA) in hypertrophic cardiomyopathy (HCM) patients. Cardiac magnetic resonance feature tracking (CMR-FT) also allows strain analysis, but little is known whether it provides incremental value to late gadolinium enhancement imaging (LGE). This study aimed to explore the relationship between CMR-FT-derived strain parameters and histopathology MF and VA and its incremental value to LGE in obstructive HCM (HOCM) patients undergoing septal myectomy.

METHODS AND RESULTS

One hundred and twenty-three symptomatic HOCM patients underwent CMR examination, followed by septal myectomy. The abnormally increased histological MF was defined as higher than the mean + 2 standard deviation (SD) of nine control autopsy subjects who had no history of cardiovascular disease. Septal strain parameters and septal LGE were evaluated at the site of surgical myectomy. Among HOCM patients without LGE, septal circumferential (P = 0.003), longitudinal (P = 0.001), and radial (P = 0.02) strains were significantly impaired in patients with increased histological MF than those without. Histological MF was significantly associated with septal circumferential strain (r = 0.32, P < 0.001), septal longitudinal strain (r = 0.42, P < 0.001), and septal radial strain (r = -0.27, P = 0.003). On multivariate analysis, septal longitudinal strain was independently associated with histological MF [β, 0.19 (0.05-0.34); P = 0.01], and VA [odds ratio, 1.10 (1.01-1.19); P = 0.02]. Moreover, septal longitudinal strain was incremental to septal %LGE in detecting increased MF (P = 0.001) and VA (P = 0.048).

CONCLUSIONS

Septal longitudinal strain at CMR is independently related to histological MF and occurrence of VA in HOCM patients. Moreover, it provides incremental value over LGE in detecting increased MF and VA.