Rapid Coronary Sinus Access in Cardiac Resynchronization Therapy: Initial Experience With the New SafeSheathCSG/Worley-1-09-STD

Cardiac resynchronization therapy requires placement of a pacing lead to activate the posterolateral left ventricle (LV) prior to its anticipated and delayed depolarization. Epicardial LV access has been achieved by placing pacing leads in coronary sinus venous tributaries; however, access to the coronary sinus and delivery systems providing support for lead placement has proven a technically challenging task. The SafeSheath Coronary sinus guide (CSG) incorporating the developed compound curve (Worley) was then tested. While its extruded material is intrinsically lacking in torquing characteristics, the addition of a similarly curved blunt tipped dilator helped to obviate this problem. In addition, its 9 Fr internal diameter was large enough to permit the use of a telescopic system employing a braided inner guide to provide additional torque for initial CS placement. While offering limited torquability, the SSCSG Worley allowed the incorporation of a truly hemostatic valve on a sheath capable of splitting in a standard fashion. The initial experience with this newly developed shape in a non-braided peel away introducer (SSCSG-W) is reported in 39 consecutive patients undergoing cardiac resynchronization therapy.

Patient Population

Data was collected on 39 consecutive patients undergoing implantation of a device for cardiac resynchronization. All patients had class III CHF, QRS duration > 120 msec, an ejection fraction of less than 35% and spontaneous or inducible sustained ventricular tachycardia. Four patients had permanent atrial fibrillation. Three patients required right-sided implantation because of lack of venous access from the left. In all patients, the right ventricular lead was placed prior to cannulation of the coronary sinus for left-sided lead placement. When necessary, the right atrial lead was placed last.

Data Collection

The following data points were prospectively collected at the time of device implantation: 1. Time required to successfully place the SSCSG-W in the CS; 2. Equipment required to place the SSCSG-W in the CS; 3. Cases where the SSCSG-W alone did not successfully cannulate the CS; 4. Presence or absence of kinking of the SSCSG-W when advanced into the coronary sinus or during the procedure; 5. Dislodgement of the LV pacing lead as the SSCSG-W was peeled away; 6. Cases where the SSCSG-W was used as part of a telescoping system for lead delivery; 7. Use of the system in right-sided implants.

Technique for CS Access

The SSCSG-W was the initial device used to attempt cannulation of the CS in all patients. Using a separate axillary vein access, the 140 cm, 0.032 Newton guidewire (Figure 1C) was advanced under fluoroscopic control into the right ventricle or out the RV outflow tract into the pulmonary artery. The straight dilator was inserted into the SSCSG-W and the straight dilator/sheath was advanced into the high right atrium (RA). Once in the high RA, the dilator was held in place and the sheath alone advanced over the wire into the right ventricle (RV). The wire was then removed leaving the tip of the SSCSG-W in the RV. The sheath was then flushed. A contrast injection system was attached to the side port of the SSCSG-W. A total of 2 cc of contrast was injected to confirm the tip location in the RV. The SSCSG-W was then withdrawn from the RV while counterclockwise torque was applied (to direct the sheath tip back toward the CS os). As the sheath was withdrawn across the tricuspid valve, multiple 2 cc puffs of contrast were injected to identify the CS ostium. In some cases, the guidewire was inserted through the hemostatic valve and used to probe for the CS ostium as well. When the ostium was identified the SSCSG-W was advanced into the CS. If the sheath alone would not engage the CS, the curved dilator (Figure 1B) was inserted into the SSCSG-W. The contrast injection apparatus was connected to the hub of the curved dilator and the process of injecting exploratory 2 cc of contrast, while withdrawing from the RV into the RA with counter clockwise torque was repeated. (Figure 5A). Additional counterclockwise torque was added to direct the tip of the guide inferiorly (Figures 5B and C) in an attempt to locate the CS. On occasion, the modified MP2 Cyber Guide alone was manipulated and advanced inside the SSCSG-W to locate and engage the CS. Once the modified MP2 Cyber Guide was in the CS, the SSCSG-W was advanced over the Cyber Guide into the CS.

Coronary Sinus Cannulation: Left-Sided Implants (36 patients): SSCSG-W Alone

In 17/36 or 47% of patients, the SSCSG-W was successful in cannulating the coronary sinus either alone, with the assistance of the guidewire or with the addition of the preformed dilator. The cannulation time ranged from 30 seconds to 5 minutes with a mean time of 126 seconds. The initial procedure was considered unsuccessful and modified if the SSCSG-W was not introduced into the coronary sinus in a five-minute time span.

Shortened SSCSG-W + Modified MP2 Cyber Guide (MP2 Cyber/Short SSCSG-W)

In 19/36 patients where the SSCSG-W alone was unsuccessful, the MP2 Cyber/Short SSCSG-W combination (Figure 2A) successfully cannulated the CS. The increased torquability of this system allowed for CS access with the MP2 Cyber Guide with an average time of 35 seconds. However, in four cases, despite successful CS cannulation with the MP2 Cyber Guide, the shortened SSCSG-W would not engage the CS for a variety of anatomic reasons. In one case, the CS ostium was too small. The 8 French MP2 successfully cannulated the CS but the 11 Fr OD SSCSG-W would not follow. Another patient who had failed CS cannulation two years previously was found to have a CS with the combination of a vertical and posterior take-off. Neither the modified MP2 Cyber Guide nor SSCSG-W would advance more than 3 mm into the CS ostium. In this case, the shortened SSCSG-W provided enough support to implant the LV lead despite suboptimal CS cannulation. In three patients with permanent atrial fibrillation, the SSCSG-W was simply too short to reach the CS despite successful cannulation with the modified MP2 Cyber Guide. All cases had massively dilated right and left atria on echocardiogram.

Kinking of the SSCSG-W

The SSCSG-W did not kink in any of the cases either during initial placement in the right heart, or during engagement and advancement into the mid-coronary sinus.

Telescoping System for Selective Target Vein Cannulation

In 27 cases, a 5-9 French guide catheter was inserted through the SSCSG-W to selectively cannulate the lateral wall target vein for either direct lead delivery or placement of an angioplasty guide wire. In all cases, the SSCSG-W remained stable in the CS as the guide was inserted into and withdrawn from the CS through the SSCSG-W. In cases where the lead was delivered to the target vein through the inner guide, the SSCSG-W provided support for the lead as the guide was cut away. Dislodgement of the LV Lead during splitting and withdrawal of the SSCSG-W. The SSCSG-W was successfully peeled away from the LV pacing lead without displacing the lead in any case. Either a soft stylet, or an angioplasty wire was left in place as the sheath was peeled away. Observation under fluoroscopy as the SSCSG-W was removed revealed that because of the shape, the tip of the SSCSG-W did not drop to the floor of the atrium as it was withdrawn from the CS, but rather followed a superior trajectory from the CS into the RA/SVC. When a telescoping system was used, the SSCSG-W provided support for the LV lead as the inner guide was removed again preventing lead dislodgement.

Right-Sided Implants (3 patients)

None of the three cases using the SSCSG-W for right-sided implants were successful. In all cases, the curve of the SSCSG-W resulted in the tip of the sheath being directed toward the lateral wall of the RA. Even when a modified MP2 Cyber Guide was added and successfully cannulated the CS, the SSCSG-W would not advance into the CS. After the failure of the first three cases, further attempts to use the SSCSG-W on the right side were abandoned. The SSCSG-W, despite its size and limited torque control, can be placed in the coronary sinus from the left side in 47% of cases in less than five minutes because of its revolutionary new shape. When the overall shape is maintained and torque control added by inserting a shaped 8 Fr MP-2 Cyber Guide (Figure 3B), the MP2 Cyber/Short SSCSG-W (Figure 4A) can be easily inserted in cases where the SSCSG-W alone was unsuccessful. Thus, using the MP2 Cyber/Short SSCSG-W for the initial attempt at CS cannulation might theoretically reduce the overall time to CS cannulation. Torque control to allow the distal sheath tip to be deflected posteriorly and inferiorly is an important addition to the new shape of the SSCSG-W. Despite removing 2-3 cm of the SSCSG-W (Figure 2B), there was sufficient SSCSG-W in the CS to provide support for either direct lead placement or an inner guide as part of a telescoping system in all but the three cases with permanent atrial fibrillation and massively dilated RA/LA. This suggests that an improved design of the SSCSG-W should maintain the same overall shape but have the braided 8 Fr catheter as the final 3 cm of the system. . In a rare patient, the ostium of the CS is too small to accept the 11 Fr OD/9 Fr ID SafeSheath CSG-W when the 8 Fr OD guide fits easily. For this purpose, a 9 Fr OD/7 Fr ID SafeSheath CSG-W will be available in the near future. Patients who have a CS with the combination of a posterior and vertical CS take-off are difficult to cannulate by any means. Neither the 8 Fr OD Cyber Guide nor the 11 French OD/9 Fr ID SSCSG-W could be advanced deeply into the CS, due to the double acute angle (superior and posterior). Despite this atypical anatomy, the SSCSG-W, when paced at the CS ostium, provided adequate support to deliver an over the wire lead. By virtue of its revolutionary new shape, the SSCSG-W can be manipulated into the CS despite its lack of torque control in 47% of patients in less than 5 minutes. In difficult cases, however, when the CS ostium is below and/or posterior to the tip of the SSCSG-W, necessary torque control can be added with the addition of a SSCSG-W shaped 8 Fr MP2 Cyber Guide as described above. The efficacy of the SSCSG-W for achieving coronary sinus access and left ventricle lead delivery was evaluated in 36 consecutive patients undergoing implantation of a device for resynchronization from the left side. The use of the SSCSG-W, with its guidewire and curved dilator alone, allowed for expedited CS access in 47% of patients in less than five minutes. In those where increased torque was required, modification of the system with an MP2 Cyber Guide braided catheter used as a torquable core provided a total success rate of 89% in less than one additional minute. Three of the four patients where the SSCSG-W would not cannulate the CS had permanent atrial fibrillation. These patients seem to require a longer sheath with a larger curve as provide in the SSCSG-W Jumbo, which was not available at the time of the study. The SSCSG-W did not kink or displace leads as it was pealed away. It provided a stable platform for creating a telescoping system. The SSCSG-W does not work from the right side. Although not universally successful because of patient anatomic variation, the SSCSG-W is a clear improvement over previously available technologies. The availability of the SSCSG-W Jumbo should increase the success rate to over 95% for left-sided implants.