Gregor J. Krings

Effective radiation dosage of three-dimensional rotational angiography in children

AIMS Three-dimensional rotational angiography (3DRA) is a relatively new but promising imaging technique in the paediatric catheterization laboratory. However, data on effective dose (ED) of this technique in children are lacking. The purpose of this study is to provide ED of 3DRA and to correlate this with parameters readily available in daily practice. Furthermore, the effect of dose-reducing techniques is evaluated. METHODS AND RESULTS Effective doses were calculated with Monte Carlo PCXMC 2.0 in 14 patients who underwent a total of 17 3DRAs at our paediatric catheterization laboratory. Median age was 5.7 years (range 1 day-16.6 years). Median ED was 1.6 milliSievert (mSv) (range 0.7-4.9). Effective dose did not correlate with age and body surface area but did correlate with dose area product (DAP) and milliGray (mGy) with r(2) of 0.75 and 0.83, respectively. Reduction of the total amount of frames from 248 to 133 per rotation resulted in further dose reduction of over 50% with preserved image quality. CONCLUSION The median ED of 3DRA in children is 1.6 mSv and correlates with DAP and mGy. This dose can be halved by applying frame reduction. A significant further dose reduction can be achieved by obtaining additional knowledge of the equipment used.

Assessing cardiac function from total-variation-regularized 4D C-arm CT in the presence of angular undersampling

Time-resolved tomographic cardiac imaging using an angiographic C-arm device may support clinicians during minimally invasive therapy by enabling a thorough analysis of the heart function directly in the catheter laboratory. However, clinically feasible acquisition protocols entail a highly challenging reconstruction problem which suffers from sparse angular sampling of the trajectory. Compressed sensing theory promises that useful images can be recovered despite massive undersampling by means of sparsity-based regularization. For a multitude of reasons-most notably the desired reduction of scan time, dose and contrast agent required-it is of great interest to know just how little data is actually sufficient for a certain task. In this work, we apply a convex optimization approach based on primal-dual splitting to 4D cardiac C-arm computed tomography. We examine how the quality of spatially and temporally total-variation-regularized reconstruction degrades when using as few as [Formula: see text] projection views per heart phase. First, feasible regularization weights are determined in a numerical phantom study, demonstrating the individual benefits of both regularizers. Secondly, a task-based evaluation is performed in eight clinical patients. Semi-automatic segmentation-based volume measurements of the left ventricular blood pool performed on strongly undersampled images show a correlation of close to 99% with measurements obtained from less sparsely sampled data.

Prospectively ECG-triggered 256-slice computed tomography findings in a patient with dextrocardia, stent-treated coarctation, and infracardial right-sided pulmonary vein deviation

A 13-year-old female patient with Turner syndrome and complex congenital heart disease including aortic coarctation presented to our hospital. Stenting of the coarctation was successfully performed with an open-cell-design non-covered stent (ev3 MaxLD). Due to the short distance between the left subclavian artery origin and the coarctation, partial overstenting of …

Make the Most of Time Temporal Extension of the iTV Algorithm for 4D Cardiac C-Arm CT

Gated 4D cardiac imaging with C-arm CT scanners suffers from insufficient image quality due to strong angular undersampling. To deal with this problem, we suggest an iterative reconstruction method with spatial and temporal total variation regularization based on an established framework which controls the relative contributions of raw data error minimization and regularization. This new method is tested on a simulated heart phantom and on two clinical data sets. We show that the additional use of temporal regularization is advantageous compared to spatial regularization exclusively, with the relative root mean square error lowered from 11.75% to 8.24% in the phantom study.

Ross-Konno for Interrupted Aortic Arch: Simplified Arch Reconstruction Using Swing-Back Technique

In neonates with interrupted aortic arch and severe left ventricular outflow tract obstruction full relief of left ventricular outflow tract obstruction and adequate aortic arch repair is required. It has been shown that neonatal Ross-Konno provides adequate and durable relieve of left ventricular outflow tract gradient. Additional aortic arch repair using the swing-back technique provides a simplified reconstruction of the arch with a tension-free, direct anastomosis. We describe the technique and results of our experience in 3 neonates.

3D Hybrid Imaging for Structural and Congenital Heart Interventions in the Cath Lab

ABSTRACT Hybrid imaging (HI) during cardiovascular interventions enables the peri-procedural visualization of the organs and tissues by means of integrating different imaging modalities. HI can improve the procedural efficacy and safety. This review provides an overview of different systems, their possibilities and the current clinical use and benefits focused on structural and congenital heart diseases. We have performed a literature search and linked the software options to the clinical use in cardiology to gain insight into the clinical use of the systems. In this review, we focus on radiation and contrast exposure, complication rate and procedure time. We found that currently available studies are limited by small cohorts. Nevertheless, HI systems for valvular procedures result in a significant decrease of radiation and contrast exposure. The largest benefit hereof is observed when HI is used in combination with rotational angiography. Furthermore, automatically determined optimal implant angle for transcatheter aortic valve implantation decreases the complication rate significantly. Congenital heart disease interventions that require 2D/3D Transoesophageal echocardiography (TEE) such as septal defects show a significant decrease in radiation and contrast exposure and procedural time when using TEE-Mono- and bi-plane cine angiography and fluoroscopy (XRF) fusion software. MitraClip procedures using these HI systems, however, show only a trend in decrease of these effects. In conclusion, major interventional X-ray vendors offer HI software solutions which are safe and can aid the planning and image guidance of cardiovascular interventions. Even though current HI technologies have limitations, HI provides support in the increasingly complex cardiac interventional procedures to provide better patient care.

Primary coronary stent implantation is a feasible bridging therapy to surgery in very low birth weight infants with critical aortic coarctation

BACKGROUND Surgical treatment of critical aortic coarctation (CoA) is difficult in very low birth weight (VLBW) infants ≤1500 g and preferably postponed until 3 kg with prostaglandins (PGE). OBJECTIVES To investigate the procedure and outcome of primary coronary stent implantation as bridging therapy to surgery in VLBW infants with CoA. METHODS Retrospective evaluation of primary CoA stenting in VLBW infants from 2010 to 2015. RESULTS Five VLBW infants with a median gestational age of 29 weeks (27-32) underwent primary CoA stenting. Indication was cardiac failure in 4 and severe hypertension in 1 patient. Age and weight at intervention were 14 days (range 12-16) and 1200 g (680-1380), respectively. Stent diameter ranged 3-5 mm. The femoral artery used for intervention was occluded in all infants without clinical compromise. Severe restenosis and aneurysm occurred in 1 VLBW infant and was successfully treated with covered coronary stents. Median age at surgical correction was 200 days (111-804) and weight 5500 g (4500-11,400). No reinterventions were required during a median postoperative follow-up of 2.8 years (0.1-5.0). Neurodevelopmental outcomes were normal and comparable between patients and siblings (4/5 gemelli). CONCLUSIONS Primary coronary stent implantation in VLBW infants with critical CoA is a feasible bridging therapy to surgery.

Percutaneous closure of a combined ventricular septal defect and paravalvular regurgitation after transcatheter aortic valve implantation: case report

Abstract Introduction Transcatheter aortic valve implantation (TAVI) is a well-accepted alternative treatment for intermediate or high-risk patients with symptomatic severe native aortic valve stenosis. As the use of TAVI increases, there is a continuous growing insight into in the technical possibilities of the procedure and a parallel decrease in complications. A serious but rare complication of TAVI is a ventricular septal defect (VSD). Case presentation We report a case of a 90-year-old woman who underwent an uncomplicated TAVI procedure. She was readmitted within 2 weeks because of dyspnoea and oedema in the legs caused by acute left- and right-sided heart failure. Echocardiography showed a VSD of 1 cm, and mild to moderate paravalvular aortic regurgitation (PAR). Discussion This is the first report in which post-TAVI both a VSD and PAR are successfully repaired via a single percutaneous procedure.

Anomalous coronary artery originating from the opposite sinus of Valsalva (ACAOS), fractional flow reserve- and intravascular ultrasound-guided management in adult patients

To describe the use of fractional flow reserve (FFR) and intravascular ultrasound (IVUS) in the evaluation of patients with anomalous coronary arteries originating from the opposite sinus of Valsalva (ACAOS).

Effect of stent implantation on blood pressure control in adults with coarctation of the aorta

BACKGROUND Stenting of coarctation of the aorta (CoA) generally results in good angiographic results and a decrease in transcoarctation pressure gradient. However, effect on blood pressure control is less clear. The goal of the current retrospective analysis was to investigate the effects of CoA stenting on blood pressure control. METHODS A retrospective analysis was conducted in consecutive adult patients with a CoA who underwent a percutaneous intervention at one of the three participating hospitals. Measurements included office blood pressure, invasive peak-to-peak systolic pressure over the CoA, diameter of the intima lumen at the narrowest part of the CoA and use of medication. The follow-up data were obtained, based on the most recent examination date. RESULTS There were 26 native CoA and 17 recurrent CoAs (total n = 43). Seven of them underwent two procedures. Mean peak-to-peak gradient decreased from 27 mmHg to 3 mmHg (p < 0.001), and minimal diameter increased from a mean of 11 mm to 18 mm (p < 0.001). Mean systolic blood pressure decreased from 151 ± 18 mmHg to 135 ± 19 mmHg at first follow-up of 3.8 ± 1.9 months and 137 ± 22 mmHg at latest follow-up of 19.5 ± 10.9 months (p = 0.001 and p = 0.009, compared to baseline, respectively). The total number of hypertensive patients decreased from 74% to 27% at latest follow-up. No significant change in antihypertensive medication was observed. CONCLUSION A clinically significant decrease in systolic blood pressure of approximately 16 mmHg was shown after (re)intervention in CoA patients, which sustained at follow-up. This sustained decrease of blood pressure can be expected to lead to less future adverse cardiovascular events.