Study results showed an important difference regarding the CV morpho-anatomical characteristics and CVC technique usability, between sexes. There was a significant difference in CV diameter in favor of the female patient group, also there was difference in favor of the same group regarding the angle of entrance as well. Regarding the usability of the CV and CVC technique, we explored the number of implanted leads, and again there was difference in favor of the female patient group. Clearly, there is a directly proportional relation between morpho-anatomical characteristics of the CV and the CVC technique usability, where this trial showed an advantage of the female patient group. These results were confirmed with multivariable analysis, which showed that CV usability increases as we move from male to female patients. It also showed that CV angle of entrance and low or no valves are significant factors for increased CV usability. Our high failure rate shows that the CVC technique is technically more complex approach, and it needs a longer learning curve to reach higher success rate [2, 4]. However, as study results showed, learning curve for CVC technique is not the only parameter that influences its success, sex-related morpho-anatomical differences can be crucial for successful lead passage also.
Cephalic vein cut-down (CVC), subclavian vein puncture (SVP) and axillary vein puncture (AVP) are the three most commonly used techniques for transvenous access. CVC was found to be the venous access of choice in 60% of the centers in Europe in a survey . This technique has its advantages and disadvantages over SV/AV puncture techniques [4, 14]. In a meta-analysis, CVC technique was associated with a lower risk of pneumothorax and lead failure compared with SVP; however, there was no significant difference in the risk of pocket hematoma/bleeding or device infection with CVC compared with SVP. The same meta-analysis showed that the acute procedural success was higher with AVP and SVP compared with CVC, and total procedure time was significantly longer with CVC compared with AVP but not SVP .
Successful lead passage through the CV or CVC technique usability depends on the morpho-anatomical parameters of the vessel and other factors like size and structure of the leads introduced via the CV, vessel wall elasticity and operator’s experience [1, 10, 15]. Morpho-anatomical characteristics of the CV were analyzed and associated with successful lead passage in one prior clinical trial. In that same trial, contrast venography results, obtained during first-time lead placement were analyzed. Venography was indicated only in cases of problematic lead introduction (15%) with either the CVC or AVP/SVP techniques. This clinical trial results showed that most common unfavorable morpho-anatomical parameters were CV diameter of ≤ 1 mm (18%), sharp curvature of the terminal CV segment as it joined the axillary vein (14%) and terminal CV bifurcation (9%) .
In one study, peri-procedural scoring system was presented for morpho-anatomical evaluation of the cephalic vein, which should facilitate the choice between the CVC and SVP/AVP techniques. Results from this trial were very encouraging regarding peri-procedural score safety and efficacy and should allow less-experienced implanters to gain more confidence during the procedure .
Another prospective study showed 17% of failure rate in lead placement through CV approach, associated with the small vessel diameter . In addition to this morpho-anatomical parameter of the CV, a different study described a technique where pre-procedural ultrasonography was used for the vessel assessment, to minimize the failure rate . Various studies have described alterations to the classical CV cut-down technique, including the use of a hydrophilic guidewire, cannulation of retro-pectoral veins, simultaneous use of two guidewires and the use of stiff angiography guidewires. These so-called “no puncture” techniques were successful in over 95% of implantations, without any major complications [11, 12, 18].
Most common short-term complications related with central venous access and lead insertions are pneumothorax, lead dislodgement, and pocket hematoma/bleeding, reportedly range from 8 to 12% [19, 20]. In a Danish pacemaker register, Kirkfeldt et al. reported that the risk of pneumothorax was almost 8 times higher with SVP in contrast with CVC technique . In addition, SVP is known to be linked with higher risk of lead failure and fractures due to the phenomenon of “subclavian crush,” where the lead is mechanically ensnared between the costo-clavicular ligament and subclavius muscle . One clinical trial reported that lead failures occurred mainly with ICD leads, a lesser age, the puncture method, lead model, and diagnosis of idiopathic ventricular fibrillation and Brugada syndrome .
However, CVC is the safest venous access obtainable for lead insertion. This access site avoids all the complications linked to SVP such as pneumothorax and subclavian crush syndrome and all at a reduced cost. Nevertheless, because it is a cut-down technique, CVC requires surgical experience with a steep learning curve, often associated with lower success rate and higher blood loss [9, 10]. In addition, AVP remains a suitable alternative with similar safety and efficacy as CVC technique, with shorter learning curve. In the same meta-analysis, they confirmed the need for continuous widespread dispersion and adoption of CVC technique .
In this retrospective study, we compared several important morpho-anatomical features of the CV and CVC technique in male and female patients scheduled for CIED implantation procedure, and at the same time, we demonstrated the advantage of this approach in the female population of patients.