Background: A mismatch between increased left ventricular mass (LVM) and blood supply may reduce coronary flow reserve, and lead to myocardial ischemia and symptoms. We investigated whether such a mismatch can be detected and quantified using contrast- enhanced computed tomography (CT) imaging.
Objectives: To compare LVM to coronary blood volume (CBV) ratio in patients with symptomatic severe aortic stenosis (AS), age- and sex-matched patients with systemic hypertension and normal subjects were selected.
Methods: Ninety-four patients with AS referred for transcatheter aortic valve implantation, 19 patients with secondary hypertrophy and 19 healthy volunteers underwent retrospective electrocardiography triggered CT. The 3D data set of the contrast-enhanced CT scan was transmitted to a dedicated CT workstation. LVM and LV end-diastolic volume (LVEDV) were calculated and the entire coronary tree was automatically detected to calculate CBV. LVM/CBV ratio was calculated and compared between patients with AS, secondary hypertrophy and normal subjects.
Results: Patients with severe AS had significantly higher LVM index compared to patients with secondary hypertrophy and normal subjects (88.2 ± 18.9 g/m2, 63.2 ± 13.4 g/m2, 54.3 ± 9.0 g/m2; respectively, P < 0.001) and a significantly higher CBV index (3.1 ± 1.2 cc/m2, 2.7 ± 0.7 cc/m2, 2.5 ± 0.6 cc/m2; respectively, P = 0.035). Despite increased CBV in patients with AS the LVM/CBV ratio was significantly increased compared to patients with secondary hypertrophy and normal subjects (31.0 ± 10, 24 ± 4.7, 22.4 ± 4.4, respectively; P = 0.047).
Conclusion: Patients with symptomatic severe AS, normal coronary arteries and left ventricular hypertrophy have increased CBV, insufficient to maintain a normal LVM/CBV ratio. Contrast CT imaging may be useful to quantify the imbalance between muscle mass and blood supply in those patients, and could potentially predict symptoms and the risk of myocardial ischemia.