Non-Alcoholic Fatty Liver Disease Modifies Serum Gamma-Glutamyl Transferase in Cigarette Smokers.

BACKGROUND: Serum gamma-glutamyl transferase (GGT) is a marker of oxidative stress, associated with increased cardiovascular (CV) risk. The impact of smoking on oxidative stress may be aggravated in individuals with non-alcoholic fatty liver disease (NAFLD). We aimed to ascertain the association of smoking on GGT levels in the presence or absence of NAFLD. METHODS: We evaluated 6,354 healthy subjects (43 ± 10 years, 79% males) without clinical cardiovascular disease (CVD) undergoing an employer-sponsored physical between December 2008 and December 2010. NAFLD was diagnosed by ultrasound and participants were categorized as current or non-smokers by self report. A multivariate linear regression of the cross-sectional association between smoking and GGT was conducted based on NAFLD status. RESULTS: The prevalence of NAFLD was 36% (n = 2,299) and 564 (9%) were current smokers. Smokers had significantly higher GGT levels in the presence of NAFLD (P < 0.001). After multivariable adjustment, current smoking was associated with 4.65 IU/L higher GGT level, P < 0.001, compared to non-smokers. When stratified by NAFLD, the magnitude of this association was higher in subjects with NAFLD (ß-coefficient: 11.12; 95% confidence interval (CI): 5.76 - 16.48; P < 0.001); however, no such relationship was observed in those without NAFLD (ß: -0.02; 95% CI: -3.59, 3.56; P = 0.992). Overall the interaction of NAFLD and smoking with GGT levels as markers of oxidative stress was statistically significant. CONCLUSIONS: Smoking is independently associated with significantly increased oxidative stress as measured by GGT level. This association demonstrates effect modification by NAFLD status, suggesting that smoking may intensify CV risk in individuals with NAFLD.

Prognostic value of Rb-82 positron emission tomography myocardial perfusion imaging in coronary artery bypass patients.

AIMS: We sought to determine the prognostic value of positron emission tomography (PET) myocardial perfusion imaging (MPI) in patients with prior coronary artery bypass graft (CABG) surgery. PET MPI has recently been shown to provide incremental risk stratification for patients with suspected coronary artery disease (CAD), but the prognostic utility of PET MPI in CABG patients has not been well studied. METHODS AND RESULTS: A multi-centre PET registry of 7061 patients who underwent Rb-82 PET MPI from four participating centres was screened. Nine hundred and fifty-three CABG patients were identified and their images were analysed. Outcomes of all-cause mortality and cardiac death were collected. With a mean follow-up of 2.4 ± 1.4 years, 128 (13.4%) all-cause deaths and 44 (4.6%) cardiac deaths were observed. Multivariable analyses, adjusted for clinical variables, demonstrated that the summed stress score (SSS) was a significant independent predictor of both all-cause mortality [HR: 1.60 (per 1 category increase in SSS); 95% CI: 1.34-1.92; P < 0.001] and cardiac death (HR: 1.80; 95% CI: 1.33, 2.44; P < 0.001). The receiver-operator characteristic (ROC) curves showed that the addition of SSS increased the area under the curve (AUC) from 0.645 to 0.693 (P = 0.014) for all-cause mortality, and from 0.612 to 0.704 (P = 0.027) for cardiac death. SSS also improved the net reclassification improvement (NRI) for all-cause mortality (category-free NRI = 0.422; 95% CI: 0.240-0.603; P < 0.001) and cardiac death (category-free NRI = 0.552; 95% CI: 0.268-0.836; P < 0.001). CONCLUSIONS: PET MPI provides independent and incremental prognostic value to clinical variables in predicting all-cause mortality and cardiac death in CABG patients.

Can balloon aortic valvuloplasty help determine appropriate transcatheter aortic valve size?

OBJECTIVES: We sought to study the potential role of balloon aortic valvuloplasty (BAV) in sizing the aortic annulus in patients before transcatheter heart valve (THV) implantation. BACKGROUND: Despite clinicians' growing experience with THV procedures, the best method of annulus sizing remains unclear. METHODS: Twenty-three patients with aortic stenosis (<1.0 cm(2)) who were undergoing surgical valve replacement were enrolled. Pre-operative echocardiographic measurements of the annulus and computed tomography measurements of valve calcium were made. Intraoperatively, a valvuloplasty balloon of known size and inflatable pressure was inserted into the aortic valve and inflated. The development of intraballoon pressure in addition to the nominal inflation pressure (AIBP) reflected the apposition of balloon and valve. Surgical annulus was measured by cylindrical sizers. RESULTS: In patients with tricuspid valves, AIBP was generated in 11 of 12 patients when the balloon diameter was greater than the surgically measured annulus, regardless of leaflet calcification (2 of 10 patients when balloon < or = surgical annulus). In bicuspid valves, high AIBP ( approximately 1 atm) was encountered with balloons that were within 1 mm of annulus size, and leaflet dehiscence occurred with larger balloons (n = 2 patients). Annulus size was underestimated by transthoracic echocardiogram and transesophageal echocardiogram compared with surgery (p < 0.001): transthoracic echocardiogram = 21.5 +/- 1.8 mm, transesophageal echocardiogram = 22.0 +/- 1.6 mm and surgical = 23.2 +/- 1.9 mm (range 20 to 27 mm, mode 22 mm). CONCLUSIONS: These data suggest that measuring AIBP during balloon aortic valvuloplasty in tricuspid valves is an important adjunctive measurement of the aortic annulus and may help in determining the appropriate THV size.