Validation of non-contrast multiple overlapping thin-slab 4D-flow cardiac magnetic resonance imaging.

BACKGROUND: Cardiac magnetic resonance (CMR) flow quantification is typically performed using 2D phase-contrast (PC) imaging of a plane perpendicular to flow. 3D-PC imaging (4D-flow) allows offline quantification anywhere in a thick slab, but is often limited by suboptimal signal, potentially alleviated by contrast enhancement. We developed a non-contrast 4D-flow sequence, which acquires multiple overlapping thin slabs (MOTS) to minimize signal loss, and hypothesized that it could improve image quality, diagnostic accuracy, and aortic flow measurements compared to non-contrast single-slab approach. METHODS: We prospectively studied 20 patients referred for transesophageal echocardiography (TEE), who underwent CMR (GE, 3 T). 2D-PC images of the aortic valve and three 4D-flow datasets covering the heart were acquired, including single-slab, pre- and post-contrast, and non-contrast MOTS. Each 4D-flow dataset was interpreted blindly for ≥moderate valve disease and compared to TEE. Flow visualization through each valve was scored (0 to 4), and aortic-valve flow measured on each 4D-flow dataset and compared to 2D-PC reference. RESULTS: Diagnostic quality visualization was achieved with the pre- and post-contrast 4D-flow acquisitions in 25% and 100% valves, respectively (scores 0.9 ± 1.1 and 3.8 ± 0.5), and in 58% with the non-contrast MOTS (1.6 ± 1.1). Accuracy of detection of valve disease was 75%, 92% and 82%, respectively. Aortic flow measurements were possible in 53%, 95% and in 89% patients, respectively. The correlation between pre-contrast single-slab measurements and 2D-PC reference was weak (r = 0.21), but improved with both contrast enhancement (r = 0.71) and with MOTS (r = 0.67). CONCLUSIONS: Although non-contrast MOTS 4D-flow improves valve function visualization and diagnostic accuracy, a significant proportion of valves cannot be accurately assessed. However, aortic flow measurements using non-contrast MOTS is feasible and reaches similar accuracy to that of contrast-enhanced 4D-flow.

Percutaneous Transapical Left Ventricular Access to Treat Paravalvular Leak and Ventricular Septal Defect.

BACKGROUND: Surgical transapical (TA) access is an established technique for structural heart (SH) procedures, but is associated with considerable morbidity. Percutaneous TA puncture provides direct access for SH procedures and may overcome the disadvantages of surgical access. This study sought to evaluate the safety of percutaneous TA left ventricular access for SH interventions. METHODS: We performed a retrospective analysis at a university hospital. Thirteen percutaneous TA procedures were performed on consecutive patients between January 2013 and July 2017 to provide LV access for transcatheter therapies. All procedures were performed under general anesthesia with three-dimensional transesophageal echocardiography guidance. RESULTS: All TA punctures were successful. Delivery sheath sizes ranged from 5 Fr to 7 Fr. Eleven of the 13 TA sites were closed with a device. Total median procedural and fluoroscopy times were 106 minutes (interquartile range, 39-117 minutes) and 26.5 minutes (interquartile range, 8.3-43.8 minutes), respectively. The planned procedure was completed successfully in all cases. One access-site complication occurred, involving embolism of a duct occluder into the pleural space and extravasation from the apical puncture site. Hemostasis of the apex site was achieved immediately with placement of three vascular plugs from a femoral approach. Two patients died prior to discharge and neither death was related to a procedural complication. There were no significant pericardial effusions. CONCLUSION: Percutaneous TA access can be achieved safely in most cases to provide access for transcatheter procedures with short procedure times. Device closure of the TA access site is reliable, with a low complication rate and no procedure-related mortality.