Factors Influencing Cardiac Sympathetic Nervous Function in Patients With Severe Aortic Stenosis: Assessment by I-Metaiodobenzylguanidine Myocardial Scintigraphy.

BACKGROUND

Numerous studies have shown that I-metaiodobenzylguanidine (MIBG) scintigraphy, an index of cardiac sympathetic nervous (CSN) activity, is useful for predicting prognosis in patients with heart failure. However, the factors influencing the CSN activity of patients with severe aortic stenosis (AS) remain unclear.

METHODS

We enrolled 91 patients with severe AS who underwent I-MIBG scintigraphy, coronary computed tomography (CCT), and transthoracic echocardiography. When CCT angiography (CCTA) showed an obstructive epicardial artery, invasive coronary angiography was performed within 1 week of CCTA.

RESULTS

There were 21 male and 70 female patients with a mean age of 84±5 years. Eighty-five (85) patients (93%) had hypertension and 13 patients (14%) had diabetes. Two (2) patients (2%) had previous myocardial infarction and eight (9%) had a previous coronary intervention. All patients had severe AS: aortic valve area was 0.63±0.18 cm and the mean pressure gradient was 56±19 mmHg. Regarding I-MIBG parameters, early heart-to-mediastinum (H/M) ratio was 3.1±0.5, delayed H/M ratio was 2.8±0.6, and the washout rate (WR) was 35%±13%. Multivariable linear regression analysis showed that coronary artery disease (β=-0.30, p=0.002) was an independent predictor of delayed H/M ratio, and that aortic valve area (β=-0.20, p=0.048) was an independent predictor of WR.

CONCLUSIONS

Our findings suggest that coronary artery disease is an independent predictor of delayed H/M ratio, and aortic valve area is an independent predictor of WR in patients with severe AS.