Diameter of the Pulmonary Artery in Relation to the Ascending Aorta: Association with Cardiovascular Outcome.

Purpose To investigate whether the pulmonary artery (PA)-to-ascending aorta (Ao) ratio is associated with outcome in unselected patients referred for cardiac magnetic resonance (MR) imaging. Materials and Methods This study prospectively enrolled 650 consecutive patients (47.2% women; mean age, 56.1 years ± 17.7 [standard deviation]). Diameters of PA and Ao were measured in axial black blood images. On the basis of previous results, a PA-to-Ao ratio of 1.0 or greater was chosen as the cutoff for further analysis. Univariable and multivariable Cox regression models were used to investigate the primary end point, which was defined as a composite of cardiovascular hospitalization and death. Results A PA-to-Ao ratio of 1.0 or greater was present in 131 (20.2%) patients. Patients with a PA-to-Ao ratio of 1.0 or greater were predominantly women (P = .010); more frequently presented with atrial fibrillation (P < .001), diabetes (P < .001), and impaired renal function (P < .001); and had higher N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels (P < .001), larger left (P = .023) and right ventricles (RV; P = .002), and worse RV function (P < .001). Patients were followed for 17.8 months ± 12.9, during which 110 patients (16.9%) reached the primary end point. By Kaplan-Meier analysis, event-free survival was significantly worse in patients with a PA-to-Ao ratio of 1.0 or greater (log-rank test, P < .001). A PA-to-Ao ratio of 1.0 or greater was independently associated with outcome by multivariable Cox regression analysis, in addition to age, NT-proBNP serum levels, and RV size. Conclusion A PA-to-Ao ratio of 1.0 or greater identified patients at risk, most likely because of elevated PA pressures. On the basis of these results, the PA-to-Ao ratio should routinely be reported at cardiac MR imaging. © RSNA, 2017 Online supplemental material is available for this article.

Determinants of Bioprosthetic Aortic Valve Degeneration.

OBJECTIVES: The aim of the present long-term study was to assess the incidence and mode of valve hemodynamic deterioration (VHD) of bioprosthetic aortic valves, as well as associated factors. BACKGROUND: Modern definitions of bioprosthetic valve deterioration recommend the use of echocardiography for the assessment of transprosthetic gradients and valvular regurgitation. METHODS: A total of 466 consecutive patients (mean age 73.5 ± 7.5 years, 56.0% women) underwent surgical bioprosthetic aortic valve replacement between 1994 and 2014. Clinical assessment, transthoracic echocardiography, and laboratory testing were performed at baseline and follow-up. VHD was defined as mean transprosthetic gradient ≥30 mm Hg and/or at least moderate valvular regurgitation on echocardiography. Patient-prosthesis mismatch was defined as an effective orifice area indexed to body surface area ≤0.8 cm2/m2. RESULTS: Patients were followed for a median of 112.3 months (interquartile range: 57.7 to 147.7 months). Among patients with complete follow-up (n = 383), 70 subjects (18.3%; 4.8% per valve-year) developed VHD after a median of 32.4 months (interquartile range: 12.9 to 87.2 months; stenosis, n = 45; regurgitation, n = 16; both, n = 9). Factors associated with VHD by multivariate regression analysis were serum creatinine >2.1 mg/dl (hazard ratio [HR]: 4.143; 95% confidence interval [CI]: 1.740 to 9.866; p = 0.001), porcine tissue valves (HR: 2.241; 95% CI: 1.356 to 3.706; p = 0.002), arterial hypertension (HR: 3.022; 95% CI: 1.424 to 6.410; p = 0.004), and patient-prosthesis mismatch (HR: 1.931; 95% CI: 1.102 to 3.384; p = 0.022). By Kaplan-Meier analysis, elderly subjects showed faster development of VHD (age <70 years, 133.5 months [95% CI: 116.2 to 150.8 months]; 70 to 80 years, 129.1 months [95% CI: 112.4 to 145.7 months]; >80 years, 100.3 months [95% CI: 63.6 to 136.9 months]; p = 0.023). By multivariate Cox regression, age, diabetes, concomitant coronary artery bypass grafting, creatinine, and VHD (p < 0.05) were significantly associated with mortality. CONCLUSIONS: On the basis of echocardiography, every fifth patient developed VHD after surgical bioprosthetic heart valve replacement. VHD was associated with renal impairment, the use of porcine tissue valves, arterial hypertension, and patient-prosthesis mismatch. Patients younger than 70 years were not affected by faster VHD.

T1 Mapping by CMR Imaging: From Histological Validation to Clinical Implication.

OBJECTIVES: The purpose of this study was to prospectively investigate the diagnostic and prognostic impact of cardiac magnetic resonance (CMR) T1 mapping and validate it against left ventricular biopsies. BACKGROUND: Extracellular volume (ECV) expansion is a key feature of heart failure. CMR T1 mapping has been developed as a noninvasive technique to estimate ECV; however, the diagnostic and prognostic impacts of this technique have not been well established. METHODS: A total of 473 consecutive patients referred for CMR (49.5% female, age 57.8 ± 17.1 years) without hypertrophic cardiomyopathy, cardiac amyloidosis, or Anderson-Fabry disease were studied. T1 mapping with the modified Look-Locker inversion recovery (MOLLI) sequence was used for ECV calculation (CMR-ECV). For methodological validation, 36 patients also underwent left ventricular biopsy, and ECV was quantified by TissueFAXS analysis (TissueFAXS-ECV). To assess the prognostic value of CMR-ECV, its association with hospitalization for cardiovascular reasons or cardiac death was tested in a multivariable Cox regression model. RESULTS: TissueFAXS-ECV was 26.3 ± 7.2% and was significantly correlated with CMR-ECV (r = 0.493, p = 0.002). Patients were followed up for 13.3 ± 9.0 months and divided into CMR-ECV tertiles for Kaplan-Meier analysis (tertiles were ≤ 25.7%, 25.8% to 28.5%, and ≥ 28.6%). Significantly higher event rates were observed in patients with higher CMR-ECV (log-rank p = 0.013). By multivariable Cox regression analysis, CMR-ECV was independently associated with outcome among imaging variables (p = 0.004) but not after adjustment for clinical parameters. CONCLUSIONS: CMR T1 mapping allows accurate noninvasive quantification of ECV and is independently associated with event-free survival among imaging parameters. Its prognostic value on top of established clinical risk factors warrants further investigation in long-term studies.