A Relook at the Transseptal Puncture: Heparin Dosing and Other Top Tips

Last week, we evaluated a 68-year-old man with increasing shortness of breath who had a coronary artery bypass graft surgery (CABG) and aortic valve (St. Jude Medical) replacement in 2007, and developed severe mitral valve annular calcification. The echocardiograms demonstrated a decreased left ventricular ejection fraction (LVEF) (35%), mild aortic stenosis (AS) and mitral stenosis (MS), but there was a discrepancy between the imaging and the Doppler-derived valve areas. Complete hemodynamic assessment in this case was needed, including a transseptal puncture (TSP) as the best way to provide definitive data. The procedures and indications for TSP are listed in Table 1.

 

The case proceeded with coronary angiography first (including left internal mammary artery [LIMA] and saphenous vein graft [SVG] angiography), then with right heart catheterization. A pigtail catheter was positioned just above the aortic valve as a marker for the TSP. The TSP system was advanced to the superior vena cava. No additional heparin beyond that in the saline flushes had been given. A TSP was performed using angiographic landmarks (Figure 1). We punctured the atrial septum with a Brockenbrough needle (observing the change from right atrial [RA] to left atrial [LA] pressure), advanced the tip of the long LA sheath dilator across the septum, removed the needle and inserted a guidewire to protect the LA, and positioned the sheath into the LA. At this time, we gave 2500 units (u) heparin intravenous (IV). After collecting the hemodynamics (Figure 2), the femoral sheaths were removed, hemostasis obtained, and we transferred the patient to the recovery room. Thirty minutes after arriving in the recovery room, the patient became deeply sedated and required reversal of his fentanyl (50 mcg) and versed (1.5 mg). He later informed us of his high sensitivity to sedatives. He returned to his baseline state pre-sedation in 45 minutes. His remaining course was uncomplicated. While evaluating the causes of the patient’s temporary obtundation, our nurse mentioned she thought we might not have given enough heparin. The activated clotting time (ACT) at the end of the case was 200 seconds (s). 

 

Given the infrequency with which we perform TSP, I asked my expert cath lab colleagues about the need for more heparin in TSP for only diagnostic purposes. In addition, I also asked, “Does the anticoagulation regimen differ for each type of procedure? Do we need to ever worry about too much anticoagulation since the electrophysiology (EP) operators do TSPs even with high INR values?”

 

As we hear from our colleagues, I also asked them to share some their top tips and advice on TSP. I also want to point out several excellent reviews on TSP in the structural heart disease era in the references section.^1-3

 

Zoltan Turi, New Jersey: Having had some unpleasant outcomes with regard to thrombus after transseptal, I tend to be on the aggressive side [re: anticoagulation]. I would have been more comfortable with an ACT in the low to mid 200s, but there’s not much evidence base, just bad experience. 

 

I’ve learned from the EP guys that after venous access, they heparinize and do the transseptal puncture, in that order. They do transseptal (granted, along with interventions) in patients fully anticoagulated, something that’s heresy to most interventional cardiologists, but it has become their standard of care; they don’t hesitate to do transseptals in patients with INRs of 2.5. Figure 3 shows the complications across INR ranges with and without clopidogrel. The bottom line for me is that I now do what the EP guys do — give heparin, typically 2000u after venous access and then aim for around ACTs of 250-300s for as long as I’m in the LA. There is a study (from the EP world, of course) comparing ACTs of 250-300 to ACTs >300s4 that suggests an even higher ACT is better. But it’s [the TSP] almost never for just diagnostic purposes, so I can’t say an ACT of 200s is wrong for diagnostics. But remember the Mullins sheath is a ‘clot magnet’, especially the old USCI (now Medtronic) Mullins sheath, which I prefer. My guess is the St. Jude Medical sheath may be less thrombogenic, but I can’t prove it.

 

My top tips for TSP: It’s very unusual for me to do TSP without echo guidance, even though that was how we did it for years. Intracardiac echocardiography (ICE) or transesophageal echocardiography (TEE) adds dramatically to the safety margin of the procedure. I would not do TSP while anticoagulated using angiographic landmarks only. In developing countries when neither is available, I usually puncture in the 90-degree lateral view, which allows fairly accurate placement and avoidance of pericardial entry if you are familiar with the x-ray landmarks (and you can stain the fossa with some dye before puncture for additional anatomic information — although I rarely do it, it’s typically quite benign). We used to breathe a sigh of relief once the LA pressure came up on the screen (yes, we always monitor pressure through the needle during TSP), but in 2017, getting across the fossa is not enough — most of the procedures we do in the LA require custom placement of the needle, and precise echo guidance is both essential and relatively simple. As to the ACT, we now compulsively check levels every 30 minutes; the EP folks check levels every 30 minutes and frequently use heparin drips to make sure they don’t let the ACT values fall too low. Finally, you still have to be extra careful to avoid air entering the LA.

 

Jeffrey Moses, New York: For keeping clots off diagnostic catheters, an ACT of 180-200s [is adequate]. For protracted therapeutic interventions, an ACT of 250s [is my choice].

 

Chet Rihal, Minnesota: This is a great question and one I get asked frequently. I err on the high side based on (bitter) experience. Most of the TSPs I do are for LA-based structural procedures and are performed with TEE guidance. 2000-4000u heparin is given after venous access to prevent thrombi on Mullins or other TS sheaths. Once in the LA, I like to use 200 u/kg of heparin (operating room-like doses) which keeps the ACT >350s for the duration of most procedures and is effective in preventing thrombi from building up in LA catheters, some of which sit in the LA for prolonged periods. The ACT can be reversed at the end of the procedure if needed. The way I look at it is the cost:benefit ratio. Development of an LA clot can be disastrous, whereas a high ACT for 1-2 hours is well tolerated. Once I went to high-dose heparin, I have not experienced any clots, something I learned from the surgeons. 

 

Matthew Price, California: I agree with Chet. Given modern-day echo guidance, doing TSP while anticoagulated is not a big deal anymore. My approach is 70-100u unfractionated heparin after access in the groin and goal ACT around 300 seconds. If for some reason I am concerned about the transseptal technique, then I give half after venous access (e.g., 3000u) and then the rest after successful crossing. We check ACTs every 15-20 minutes. 

 

My top TSP tips:

 

Jonathan Tobis, California: I wait to give heparin until after I perform the transseptal. I recognize that this has not been studied formally and that the EP people give heparin before crossing the septum. But I am a creature of habit or primary education and I have seen no reason to change. I recognize that now that we do TEE guidance for the transseptals, the risk of puncturing the aorta or the transverse pericardial space is exceedingly unlikely. I measure ACT and keep it about 250s for the procedure.

 

My top TSP tips: I would emphasize that TEE helps to make the procedure safer and also makes the 3D anatomy more understandable compared to the early days, when fluoro guidance was all that we had. The operator needs to be meticulous, a common request for all interventions, but remember that you have a 3-foot long spear in your hands. Also, you are working in the left atrial side, so you have to be very careful about air embolism. There is also a learning curve of getting the feel of the TS catheter and introducer as it brushes along the curvature of the atrial septum from anterior to posterior, and to slide it down or up according to the optimal entry site.

 

Mort Kern, California: My top tips for TSP: Probably the most important consideration before TSP is ensuring the exclusion of LA thrombus (by TEE) even in chronically anticoagulated patients. 

 

Should we do TSP with high INR? Since many operators use echo guidance for the TSP, some (especially the EP operators) feel comfortable doing TSP without holding coumadin. For some of us old-school operators, using angiographic landmarks only, it is recommended that the INR should be <1.6. 

 

TSP with transesophageal or intracardiac echocardiography is now preferred to facilitate a safe and accurate puncture. Accuracy of the puncture site is mandated for certain interventional procedures (e.g., MitraClip [Abbott Vascular]), and can increase the success of other percutaneous therapies (e.g., posterior puncture for medial paravalvular defect closure). Drs. Rihal and colleagues1 remind us of the best positions for TSP puncture for various transseptal interventions (Figure 5).

 

Be sure you have all the TSP equipment you’ll need. As a small volume percutaneous coronary intervention (PCI)-No SOS lab, we rarely perform TSP and therefore must ensure we have all the needed guidewires, sheaths and needles (Figure 6). In Long Beach, our structural interventions are limited to atrial septal defect/patent foramen ovale (ASD/PFO) and transcoronary ablation of septal hypertrophy (TASH) procedures. We recognize that in the modern era of structural heart interventions and advanced EP techniques, TSP is commonplace in such larger programs. Each lab and operator has their individual preferences for needles, sheaths, and approach. 

 

Lastly, consider the contraindications to TSP, which include inability to lie supine, left or right atrial thrombus, atrial myxoma, and absence of right femoral venous access to the right atrium due to masses, thrombus, or other obstructions. Consider the risks carefully for patients with distorted cardiac anatomy resulting from congenital heart disease, dilated aortic root, marked atrial enlargement, or thoracic skeletal deformity. The potential complications of TSP are listed in Table 2.⁴ 

 

 

Drs. Alkhouli, Rihal, and Holmes¹ address appropriate training for TSP. Current training relies on performance of TSP on patients with supervision by an experienced operator. Approximately 30 TSPs are needed for a trainee to pass the steepest area of the learning curve.² Use of virtual reality simulators can result in shorter training times and superior post-training performance.³ Partnering among different specialties involved in transseptal procedures (electrophysiology, structural heart disease, congenital heart disease) can afford trainees with an excellent opportunity to acquire the necessary TSP skills within the short span of their training programs. 

 

 

TSP and subsequent LA-related interventions expose the patient to the risk of thrombotic events, namely stroke/TIA. Anticoagulation with intravenous heparin and meticulous attention to flushing sheaths (i.e., no thrombus and air bubbles) are critical. Many operators give 3000-5000u of heparin to achieve an ACT >250-300s when the transseptal system is introduced into the right heart and for interventions, many give another 5000u after the puncture has been completed, frequently checking the ACT to keep it above 300s.

 

I hope you’ve found this brief update of TSP helpful as we continue our advances in structural heart interventions.