Characterization and clinical significance of right ventricular mechanics in pulmonary hypertension evaluated with cardiovascular magnetic resonance feature tracking.

BACKGROUND: Prognosis in pulmonary hypertension (PH) is related to right ventricular (RV) function. Quantification of RV mechanics may offer additive value. The objective of our study is to determine the feasibility and clinical and prognostic value of RV strain analysis by cardiovascular magnetic resonance (CMR) based feature tracking (FT) in PH. METHODS: We retrospectively enrolled 116 patients (age 52.2 ± 12 years, 73.6 % women) referred to CMR for PH evaluation who underwent right heart catheterization within 1 month. Using dedicated FT software, peak global longitudinal and circumferential RV strain and strain rates (GLS, GCS, GLSR, and GCSR, respectively) were quantified from standard cine images. Using multivariate regression analysis, we evaluated the associations of strain with a composite endpoint of death, lung transplantation, or functional class deterioration. RESULTS: RV strain analysis was feasible in 110 (95 %) patients. Patients were classified into: Group A (no PH, normal right ventricular ejection fraction [RVEF]; n = 17), Group B (PH, normal RVEF; n = 26), or Group C (PH, abnormal RVEF; n = 67). All strain and strain rate values were reduced in Group C. Furthermore, GCSR was significantly reduced in Group B (-0.92 [-1.0/-0.7]; p < 0.001) compared to Group A (-1.12 [-1.3/-0.9]; p < 0.001). After adjustment for six clinically meaningful covariates, GLS (hazard ratio 1.06; p = 0.026), GLSR (hazard ratio 2.52; p = 0.04), and GCSR (hazard ratio 4.5; p = 0.01) were independently associated with the composite endpoint. GCSR successfully discriminated patients with and without events (p = 0.01). CONCLUSIONS: Quantification of RV strain with CMR-FT is feasible in the majority of patients, correlates with disease severity, and is independently associated with poor outcomes in PH.

Low- vs. standard-dose coronary artery calcium scanning.

AIMS: This study was designed to assess the accuracy of coronary artery calcium scans (CACS) acquired at radiation doses below mammography and low-dose lung scanning, compared with standard-dose CACS. METHODS AND RESULTS: CACS was performed in 102 consecutive patients at 120 kVp; all were imaged at standard-dose mAs levels ranging from 30 to 80 mAs determined by their weight, with iterative reconstruction (IR) level 3, and at 50% of the standard-dose mAs with IR level 7 to compensate for the expected increased noise with lower mAs. The low- vs. standard-dose mAs was 24.5 ± 8.8 vs. 48.5 ± 17.8 mAs (P < 0.0001), and the radiation exposure was 0.37 ± 0.16 vs. 0.76 + 0.34 mSv (P < 0.0001). The Agatston score correlation between the low and high dose was excellent (r = 0.998, P < 0.0001) over a range of scores from 0 to 2512. The weighted kappa for agreement of standard CAC risk categories was 0.95 (95% CI 0.83-0.97). The mean of the differences between individual low- and standard-dose Agatston scores was 17.4 ± 25.8, lower than the reported variability of two scans performed with the same mAs. CONCLUSION: There was excellent agreement of CACS-based risk classification at low and standard doses, with lower interscan variability than with reported identical doses. The low-dose CACS radiation exposure was less than the approved screening tools of mammography and low-dose lung scanning.

Diagnostic accuracy of coronary ct for the quantification of the syntax score in patients with left main and/or 3-vessel coronary disease. Comparison with invasive angiography.

BACKGROUND: The SYNTAX score helps in the treatment decision in multivessel coronary disease. Coronary computed tomography angiography (CTA) can measure the SYNTAX score but has been used in few patients with multivessel disease. Our aim was to assess the feasibility, accuracy and reproducibility of SYNTAX score with CCTA compared with invasive coronary angiography (ICA) in de novo left main and/or 3-vessel disease. METHODS: 57 patients with new left main and/or 3-vessel disease on ICA and a CCTA performed within the previous month were included. The SYNTAX score was calculated retrospectively for both modalities. Agreement for the global score, vessel score, different components and inter-readers was evaluated with intraclass correlation coefficient (ICC). The ability to classify SYNTAX score categories (low, intermediate and high) was assessed using weighted kappa (K) coefficient. RESULTS: CCTA-based SYNTAX score showed an acceptable concordance (ICC=0.64) and good correlation (r=0.65, p<0.001) with ICA. ICC per vessel and component ranged from 0 to 0.73. There was good agreement classifying the SYNTAX score categories (K=0.53) and interobserver reproducibility (ICC=0.85). CCTA demonstrated high diagnostic accuracy (0.84) for detecting patients in the high score group. No patient with a high CCTA SYNTAX score had a low risk score by ICA that would suggest benefit from percutaneous revascularization. CONCLUSIONS: CCTA showed good correlation, acceptable concordance, and high reproducibility for the quantification of the SYNTAX score in de novo left main and/or 3-vessel coronary disease. A high CCTA SYNTAX score identified a group of patients less likely to benefit from percutaneous coronary intervention.