[Percutaneous transjugular thrombectomy in iliocaval thrombosis-- initial experience with a newly developed 12F balloon sheath]

PURPOSE

To evaluate the feasibility of percutaneous thrombectomy for the removal of floating iliocaval thrombi using a balloon sheath.

MATERIALS AND METHODS

A newly developed balloon sheath (inner diameter: 12-F; outer diameter: 18-F) was tested in two patients with extensive iliocaval thrombosis. Mechanical thrombectomy was performed due to recurrent pulmonary embolism under therapeutic anticoagulation in antiphospholipid-antibody syndrome and, respectively, paraneoplastic thrombosis without a decrease of fresh thrombus mass in spite of pharmacological treatment. Via a transjugular access (20-F), the sheath was advanced retrogradely into the inferior vena cava. After blocking of the vessel, mechanical fragmentation was performed through the working channel coaxially, using a temporary vena cava filter as a rotating basket (max. diameter: 30 mm). Residual thrombus fragments were removed by aspiration.

RESULTS

The thrombectomy balloon sheath tested allowed a complete removal of fresh thrombi after fragmentation. In addition, older clot material was obtained. Balloon occlusion prevented the central embolization of thrombus fragments. Clinical signs indicating pulmonary embolism were not seen. The fluid loss due to aspiration was negligible.

CONCLUSIONS

The newly developed 12-F balloon sheath proved to be efficient for the extraction of large thrombi. Balloon occlusion safely prevented central embolization of thrombus fragments proximal to the sheath.

[Diagnosis and visualization of renal artery stenosis by color-coded Doppler ultrasonography. Comparison of central and peripheral flow patterns]

PURPOSE

Comparison between central and peripheral flow patterns with color-coded duplex sonography in the diagnosis of renal artery stenosis.

MATERIALS AND METHODS

In a prospective study with sixty-six patients systolic velocity (central examination) and acceleration index (peripheral examination) were determined using color-coded duplex sonography examination in order to detect and visualize renal artery stenosis. If the central and peripheral measurements were negative, no angiography was performed. In contrast, if one of the methods yielded a pathological finding, catheter angiography was performed to verify the results (21 patients), as well as in two other unclear cases.

RESULTS

An agreement between central and peripheral measuring was seen in 49 of 66 patients. In ten patients central and peripheral measurements showed different results. In seven cases the peripheral measurements were not clear. Compared to angiography, peripheral measurement showed a sensitivity of 60%, a specificity of 75% and a positive predictive value of 81.8%. In contrast, central examination had a sensitivity of 100%, a specificity of 75% and a positive predictive value of 88.2%.

CONCLUSIONS

Based on our preliminary results, the measurement of the systolic velocity peak seems to be an effective method to detect renal artery stenosis.

The performance of non-ECG gated chest CT for cardiac assessment - The cardiac pathologies in chest CT (CaPaCT) study

PURPOSE

Evaluating the prevalence of CAD on non-ECG gated chest CTs, image quality (IQ) and the clinical performance of the CAD-RADS classification for predicting cardiovascular events (CVE).

METHODS

215 consecutive patients referred for chest CTs between May 2016 and March 2018 were included (3rd-generation DSCT) using non-ECG gated acquisitions with automated tube voltage selection (110kV_qual.ref/40mAs_qual.ref), pitch 2.65-3.0 and individualized contrast media injection protocols. Dedicated cardiac post-processing reconstructions (0.6 mm/0.4 mm/Kernel Bv36) were added to standard chest reconstructions. Two independent cardiac radiologists performed a 3-step analysis. In case of discrepancy, a third reader gave the final decision. Step 1: visual presence of calcifications; 2: scans with calcifications assessed for IQ using a 5-point Likert scale (poor/sufficient/moderate/good/excellent); 3: stenosis severity was analysed in detail (if Likert sufficient-excellent using CAD-RADS). Electronic patient files were checked to see if pathology was previously mentioned (incidental) and whether patients developed an CVE during follow-up.

RESULTS

1: Calcifications were present in 156/215 cases (72.6 %), 74 of these were incidental. 2: In 68/156 (43.6 %) patients with calcifications IQ was rated sufficient-excellent. 3: CAD-RADS≥3 was seen in 39/68 patients (57.4 %), 12 times (30.8 %) findings were incidental. During follow-up (median 16 [0-35] months), 7/39 (18 %) patients with CAD-RADS≥3 developed a CVE. 17 patients died during follow-up.

CONCLUSION

Coronary calcification on non ECG-gated chest CTs was detected in 72.6 % of patients, cardiac assessment was feasible in nearly half of these patients. Only patients with a CAD-RADS≥3 developed CVE, therefore the CAD-RADS may help identify and guide patients at risk of future CVE.

Direct pre- and post-ablation cardiac magnetic resonance imaging of tissue characteristics in patients with typical atrial flutter

Funding Acknowledgements

Type of funding sources: None.

Background

Real-time cardiac magnetic resonance (CMR) imaging as guidance in electrophysiology (EP) procedures enables a detailed overview of the anatomy of the heart and surrounding structures, active and passive catheter tracking, and real-time visualisation of ablation lesions throughout the ablation procedure, without using fluoroscopy.

Purpose

To evaluate ablation induced changes in tissue characteristics of the cavotricuspid isthmus (CTI), directly following typical atrial flutter ablation in an interventional cardiac magnetic resonance (iCMR) suite.

Methods

Nine patients with symptomatic typical atrial flutter were referred for CTI ablation in an iCMR suite. Procedures were performed using a 1.5T MRI scanner. Pre-ablation imaging included T2-weighted edema imaging in the right anterior oblique (RAO) and transversal view. During the ablation procedure, CMR imaging facilitated active tracking and real-time navigation of both diagnostic and ablation catheters, as well as visualisation of the ablated tissue. Post-ablation imaging to evaluate the target tissue again included T2-weighted edema imaging as well as dark-blood late gadolinium enhancement (LGE) imaging. Data regarding post-ablation imaging findings, ablation outcome, and complications were collected for all patients. All patients provided written informed consent.

Results

In eight of the nine patients, T2-weighted imaging was successfully performed pre- and post-ablation, which identified myocardial edema at the CTI ablation line in all patients (Figure 1A-B). Due to time restraints, post-ablation LGE imaging was performed in five patients, which showed pathological signal intensity at the level of the CTI in all five patients (Figure 1C). Bidirectional block of the CTI was confirmed by differential pacing in eight patients. No complications occurred during or immediately after the procedures. In one patient, the registration of intracardiac electrograms was not possible due to technical problems and the patient was transferred to a conventional EP lab to complete the ablation following our predefined bailout procedure.

Conclusion

Real-time CMR guided CTI ablation in patients with typical atrial flutter is safe and successful. CMR enables accurate visualisation of the CTI line and provides immediate post-ablation evaluation of tissue characteristics at the ablation target location.

Figure 1. T2-weighted edema cardiac magnetic resonance (CMR) imaging in the right anterior oblique (RAO) view acquired pre- (A) and post-ablation (B) during interventional CMR ablation therapy. Late gadolinium enhancement (LGE) CMR in the RAO view post-ablation (C) of the same patient. The blue arrowheads indicate the cavotricuspid isthmus (CTI) line. High signal intensity at the level of CTI is observed post-ablation on both T2-weighted (indicating edema) and LGE (indicating cell membrane rupture) images.

First clinical experience with cardiac magnetic resonance guided typical atrial flutter ablation with the integration of active catheter tracking and electro-anatomical mapping

Funding Acknowledgements

Type of funding sources: None.

Background

In our university hospital, we previously implemented cardiac magnetic resonance (CMR) guided typical atrial flutter ablation in a pre-existing MRI suite which was transformed into an interventional cardiac MRI (iCMR) suite.

Purpose

To describe our first clinical experience with integration of active catheter tracking and dedicated electro-anatomical mapping (EAM) system for the treatment of typical atrial flutter in a transformed pre-existing MRI suite.

Methods

Between February 2021 and December 2021, all consecutive patients planned for CMR guided typical atrial flutter ablation were included in this analysis. The procedure was performed under general anaesthesia. Feasibility and safety of active catheter tracking and the integration with a dedicated EAM was evaluated. All patients provided written informed consent.

Results

In total, nine patients underwent CMR guided atrial flutter ablation. Procedural characteristics are presented in Table 1. In all patients, both active catheter tracking and the integration with EAM were performed successfully. Bidirectional cavo-tricuspid isthmus block was achieved in eight out of nine patients and confirmed by differential pacing using intracardiac electrograms and EAM. In one of these eight patients, the registration of intracardiac electrograms was not possible due to technical problems and the patient was transferred to a conventional electrophysiology lab to complete the ablation following our predefined bailout procedure. Seven out of nine patients were in sinus rhythm at the start of the procedure, one in nodal rhythm with atrial bigeminy, one patient required electrical cardioversion for atrial fibrillation prior to the procedure. No periprocedural complications occurred.

Conclusion

CMR guided typical atrial flutter ablation in a transformed pre-existing MRI suite using active catheter tracking and a dedicated EAM system is feasible and safe based on this small population. It allows for detailed visualisation of catheters and individual patients anatomy. Further studies in larger patient populations are required to evaluate whether iCMR is cost effective and can improve clinical outcome of typical atrial flutter ablation and other arrhythmias.