What can happen during coronary sinus lead implantation: dislocation, perforation and other catastrophes

Technical aspects in coronary sinus Reducer implantation

Refractory angina is a growing problem, predominantly due to advanced coronary artery disease, associated with a reduced quality of life and an increased hospitalisation rate with a corresponding impact on healthcare resources. There is an unmet clinical need to be addressed by novel therapeutic approaches. Over the last few years, a treatment approach causing a controlled coronary sinus narrowing by implantation of a balloon-expandable, hourglass-shaped, stainless steel mesh (i.e., the coronary sinus Reducer) has arisen with promising initial short-term and midterm results, in terms of reducing angina and ischaemia burden and improving quality of life. Guidance with proper implantation algorithms and knowledge on how to address potential complications will improve interventional outcomes and foster a wider application of this novel therapeutic approach. In this review, we summarise the implantation technique, the causes of potential complications, and algorithms focusing upon their practical management, based on the experience of the authors.

Introducer Development for Coronary Sinus Access From Parasternal Mediastinotomy

OBJECTIVE

Right parasternal mediastinotomy with right atriotomy has been used clinically for pacemaker insertion. A similar approach might facilitate access to the coronary sinus for biventricular pacing and other manipulations when more conventional approaches are not feasible. The primary barrier to this is lack of appropriate introducers and techniques.

METHODS

Anatomically derived introducers were developed in 2 anesthetized domestic pigs using data from computerized axial thoracic tomography. Each digitized tomogram defined a unique introducer shape and was constructed using 3-dimensional (3D) modeling software and printing. Each parent pig then underwent surgery demonstrating coronary sinus lead insertion, using its custom-configured introducer. Next, with institutional review board approval, 65 patients were identified who had undergone conventional endocardial coronary sinus lead insertion followed by thoracic scanning. These tomograms were used to design appropriately curved introducers for human anatomy.

RESULTS

Fifty-one introducer paths were defined following anatomic pathways and avoiding bends inconsistent with materials used for commercial peel-away introducers. Each path was defined by a bend and distance toward the coronary sinus ostium and a hook and twist out of plane to align with the local orientation of the coronary sinus. The average dimensions were the following: distance, 67 mm; bend angle, 47 degrees; hook angle, 39 degrees; and twist angle, 20 degrees. A prototype cannula was tested for fit in a fresh frozen postmortem human specimen.

CONCLUSIONS

Parasternal mediastinotomy access to the coronary sinus for cardiac resynchronization, mitral annuloplasty, and instrumentation is feasible. Human computerized tomographic scans can be used to define curvatures and dimensions for marketed introducers.

Lead positioning strategies to enhance response to cardiac resynchronization therapy

Left ventricular lead position is one of the main determinants of CRT response. There are several approaches in LV lead positioning that include favoring an optimal anatomical position or targeting either the segment with maximal mechanical dyssynchrony or a region with maximal electrical delay. The conventional LV lead implantation faces several technical difficulties that may prevent the obtaining of a stable position and good performance of the LV lead without phrenic nerve stimulation. In addition, implant of the LV pacing lead in areas with myocardial scar may result in less than optimal cardiac resynchronization. Several strategies have been proposed to overcome all these obstacles including multimodality cardiac imaging to help in preprocedural or intraprocedural identification of the latest activated areas of the LV and the potential anatomical constraints. In selected patients, the surgical implant may be a solution to overcome these constraints. In the future, LV endocardial or epicardial multisite pacing may deliver an enhanced response to CRT.