Patients Characteristics
Based on the exclusion criteria, 20 patients were excluded from this study (2 cases of ascending aortic replacement and/or aortic valvuloplasty, 2 cases of moderate or severe AS, 16 cases of IE). In total, 126 patients were eligible for this study (mean age 67 ± 12 years, male 73%). Table 1 shows their baseline clinical characteristics, comorbidities and echocardiographic measurements. Three fourths of the study subjects were hypertensive, and 43% of them had chronic kidney disease (CKD) (estimated glomerular filtration rate < 60 ml/min/1.73m2). Thirteen (10%) patients had a connective tissue disease (rheumatic arthritis 5, systemic lupus erythematosus 2, Marfan syndrome 1, Takayasu arteritis 1, autosomal dominant polycystic kidney disease 2, polymyalgia rheumatica 1, Behçet’s disease 1). More than half of them had severe AR, resulting in their dilated left ventricular (LV) size (LV end-diastolic diameter: 60 mm) with slightly reduced LV ejection fraction (51%) as well as slightly dilated sinus of Valsalva (38 mm) (median values, respectively).
Etiologies of AR (Table 2)
In all the study subjects, the most common etiology of AR was cusp bending (33.0%), followed by aortic root enlargement (22.2%), and bicuspid AV (17.4%). Seven (5.5%) patients had both AV cusp bending and aortic root enlargement. Even normal finding was also noted in 7.9% of the subjects. In AV cusp bending, right coronary cusp (RCC) was the most affected (90.5%, 38 out of 42 cusp bending cases).
Comparison between Cusp Bending and Non-Cusp Bending Groups(Table 3)
As the next step, all the study subjects were classified into 2 groups with or without aortic cusp bending on any cusp. The number of patients with cusp bending was 49 (mean age 72 ± 7 years), whereas that of those without cusp bending was 77 (mean age 64 ± 14 years). The age was significantly higher in the cusp bending group (p = 0.0017). While the patients with aortic cusp bending had significantly lower height (159 vs 165 cm, median, p = 0.0037) and less body surface area (1.58 versus 1.63 m2, median, p = 0.0287), LV echo measurements did not differ between the 2 groups. However, those with cusp bending had smaller diameters of Valsalva sinus (36 vs 39 mm, median, p = 0.0188), ST junction (30 vs 33 mm, median, p = 0.0150) and mid-ascending aorta (35 vs 38 mm, median, p = 0.0097). In addition, patients with mitral prolapse were observed only in the cusp-bending group (8% vs 0%, p = 0.0053).
AR Etiologies According to Age (Table 4)
Subsequently, all the subjects were re-classified into 2 groups based on their age at 65 years: the elderly group (n = 85, mean age 74 ± 5 years) and the younger group (n = 41, mean age 52 ± 11 years). In the elderly group, cusp bending was the most frequent cause of AR (48.2%), and RCC was the most affected cusp (90.2%). On the other hand, in the younger group, bicuspid AV was the most common etiology (36.5%), and cusp bending accounted for only 19.5% in this group.
To examine the contributing factors to aortic cusp bending, logistic regression analysis was performed with age, hypertension, diabetes, CKD and connective tissue diseases included as dependent variables, which revealed that age was the only factor associated with cusp bending (Table 5).