An Unusual Complication of Transseptal Puncture

Abstract

The interatrial septum is a structure with complex embryological development. The true atrial septum is a circumscribed structure, and transgression outside of this area during transseptal puncture may result in entry into the extracardiac space or aorta that may result in a pericardial effusion or cardiac tamponade. (Level of Difficulty: Intermediate.)

Graphical abstract

A 76-year-old man with a history of paroxysmal atrial fibrillation (CHA2DS2-VASc score of 4), hypertension, heart failure with recovered ejection fraction, and history of cardiac resynchronization therapy-defibrillator implantation underwent colonoscopy for gastrointestinal bleeding, while receiving anticoagulation therapy with rivaroxaban. Colonoscopy demonstrated multiple colonic polyps along with a 3 cm × 5 cm-ulcerated mass that appeared to be malignant in the transverse colon, subsequently diagnosed as moderately differentiated adenocarcinoma. His HAS-BLED score of 4 and ongoing unresolved risk of gastrointestinal bleeding prompted a referral for left atrial appendage occlusion (1).

Learning Objectives

• •To understand the anatomical boundaries of the true interatrial septum.
• •To understand the relationship between the interatrial septum and extracardiac structures and the potential for complication with inappropriate transseptal puncture technique.

Medical History

Intravenous heparin was administered prior to attempts at transseptal access. The 11-F sheath in the right femoral vein was exchanged for a 16-F Check-Flo (Cook Medical, Bloomington, Indiana) sheath over the wire. A 10-F SL1 sheath (Abbott Medical, Chicago, Illinois) was advanced through the Check-Flo sheath into the left subclavian vein over the guidewire. A radiofrequency transseptal needle (Bayless Medical, Mississauga, Ontario, Canada) was advanced to the tip of the 10-F SL1 sheath and dilator. Transesophageal echocardiographic and fluoroscopic guidance were used to bring the entire apparatus down; however, tenting of the fossa ovalis was not appreciated. Significant lipomatous interatrial septal hypertrophy was noted (Figure 1). To further aid in visualization, operators switched from transesophageal echocardiography to intracardiac echocardiography. Following multiple attempts at transseptal puncture in the fossa ovalis, the radiofrequency needle was advanced beyond the tip of the SL1 sheath, and radiofrequency energy was delivered (15 W for 2 s). Bubbles were visualized in the left atrium, and pressure recordings also confirmed left atrial access (Figures 2 and 3). Given the unusual difficulty of transseptal access, confirmation of left atrial location was sought using contrast through the SL1 sheath. However, contrast was visualized in the pericardial space (Figures 4 and 5, Videos 1 and 2). It was believed the transseptal needle punctured the anterosuperior plane of the interatrial septum, traversing the transverse pericardial sinus before entering the left atrium.

Figure 1.

Transesophageal Echocardiography Bicaval View

(Star) Interatrial septum hypertrophy. Sparing of the fossa ovalis (arrow).

Figure 2.

Right and Left Anterior Oblique Projections of Wire Advancement Following Transseptal Puncture

Figure 3.

Left Atrial Pressure Recording

Figure 4.

Right Anterior Oblique Projection of Contrast Extravasation Into Transverse Pericardial Space and Simultaneous Contrast Flow Into the Left Ventricle

Figure 5.

Left Anterior Oblique Projection of Contrast Extravasation Into Transverse Pericardial Space

Differential Diagnosis

As a result of contrast visualization within the pericardial space, inadvertent pericardial access was the primary differential diagnosis.

Investigations

The patient was monitored using transesophageal echocardiography and intracardiac echocardiography for 60 min. There was minimal pericardial effusion.

Management

Given inadvertent pericardial access, the procedure was aborted. A follow-up transthoracic echocardiogram obtained the next day revealed no significant pericardial effusion or evidence of hemodynamic compromise. The patient was discharged home.

Discussion

Transseptal access of the left atrium was first described in 1947 by Cournand (2) for the purpose of directly measuring the left atrial and pulmonary vein pressure and refined by Brockenbrough and Mullins (3). In the current era, transseptal puncture is widely used during many common cardiac procedures and is performed without the aid of transesophageal echocardiography or intracardiac echocardiography in many countries. Transseptal access, despite being increasingly performed and having an excellent safety profile, can be associated with complications regardless of indication (4).

Understanding the embryological development and anatomy of the interatrial septum is critical for operators performing this procedure. The classic description of the interatrial septum represents an extensive area of muscular tissue interposed between the left and right atria which is bound superiorly by the SVC ostium, posteriorly by the folds of the atrial wall, inferiorly by the inferior vena cava ostium, anteroinferiorly by the coronary sinus orifice, anteriorly by the septal leaflet of the tricuspid valve, and anterosuperiorly by the noncoronary sinus of Valsalva (5,6). It is important to note that on ex vivo anatomic dissection, removal of most of these structures will result in opening of the right atrial wall and arrival outside of the heart and into the pericardial space (7). The “true” atrial septum separating the left and right atrial chambers is a relatively small area encompassing approximately 20% of the total interatrial septum (IAS) area, and includes the floor of the fossa ovalis and its immediate muscular inferoanterior rim (Figure 6) (8).

Figure 6.

Component Parts of the Definitive Atrial Septum

IVC = inferior vena cava; SVC = superior vena cava.

Reprinted from Naqvi et al. (8).

The anterosuperior portion of the septal plane is located immediately posterior to the transverse pericardial sinus and the aortic root. This is highlighted by an observation that increased aortic size is correlated with decreased size and mobility of the atrial septum (9). Interventional procedures in this part of the septal plane carry a risk of exiting the heart or entering the aortic root, as the septal structures directly separating the right and left atria are considerably less than the entire septal plane that is visualized on imaging. Attempts at transseptal puncture outside of the fossa ovalis, although in the septal plane, may result in penetration into extracardiac tissues before entering the left atrium and can cause cardiac tamponade acutely or subacutely after the transseptal sheath has been retracted (6). Moreover, small “pits” and “crevices” have been described in this region, which may lodge the tip of a transseptal puncture device, giving a false impression of having “tented” the IAS (10). This complexity may be compounded by lipomatous interatrial hypertrophy, which can hinder transseptal needle penetration, lead to increased difficulty with instrument maneuverability, and dissection into the vascularized fibrofatty tissue plane, ultimately resulting in hemopericardium, as in the present case (Table 1) (11).

Table 1.

Tips for Successful Transseptal Puncture

Problem	Tips and Tricks
1.Fibrosed septum and inability to advance the sheath	•Use sequential dilation after obtaining transeptal access, preferably with stiffer dilators over a 0.032-inch Amplatz guidewire∗ in the left superior pulmonary vein. •If the transseptal sheath buckles in the right atrium when advanced, place the 0.032-inch Amplatz wire in the right superior pulmonary vein to provide a co-axial rail for sheath advancement. •In difficult cases, use a balloon septostomy.
2.Difficult visualization of the septum with transesophageal echocardiography	•Consider alternate echocardiography modalities such as intracardiac echo. •Consider transeptal puncture with contrast injection from the needle, in order to delineate the inter atrial septum. •Measure intracardiac pressures to identify an entry into the left atrium.
3.Mechanical aortic valve	•The non-coronary cusp localizes the most posterior and inferior aspects of the aortic valve fluoroscopically. Puncture should be more inferior and posterior to this landmark.
4.Prior atrial septal closure	•Obtain operative records. •If device closure, puncture can be performed inferior to the device. •If suture closure, puncture can be performed as usual.
5.Persistent left superior vena cava	•Transeptal puncture can be problematic from a “drop down” approach as the apparatus may routinely drop into the patulous coronary sinus ostium. A “push up” approach with ultrasonography (ICE) might be helpful. •A wire puncture with SafeSept† followed by sequential dilation may be helpful.
6.IVC filter	•Transeptal puncture can be safely performed with almost all existent IVC filters. •Understanding of the filter design is a prerequisite.
7.Interrupted IVC	•Approach from hepatic vein or superior approach through the subclavian or internal jugular vein.
8.Complex congenital heart disease with prior surgery	•Consult with a pediatric cardiologist/pediatric cardiac electrophysiologist.
9.Interaction of transeptal apparatus with pacing or defibrillation leads	•The transeptal apparatus should be advanced over a wire medial to the pacing leads in the left anterior oblique projection.
10.Aneurysmal atrial septum bowing to the posterior wall of the left atrium that could result in a puncture through the posterior wall of the left atrium	•A wire puncture with SafeSept, followed by a pigtail wire to eliminate the probability of trauma to the posterior wall of the left atrium.‡

ICE = intracardiac echocardiography; IVC = inferior vena cava.

^∗Amplatz; Cook Medical, Bloomington, Indiana;

^†SafeSept; Baylis Medical, Toronto, Ontario, Canada;

^‡Protracts; Baylis Medical.

Additionally, the membranous ventricular septum can be divided into 2 segments based on the attachment of the septal leaflet of the tricuspid valve: a superior atrioventricular segment and an inferior interventricular segment. Inadvertent puncture into the superior atrioventricular portion of the membranous ventricular septum may result in direct right atrial-left ventricular communication, analogous to the Gerbode defect (Figure 7) (12).

Figure 7.

4-Chamber Section Through the Heart

Four-chamber section through the heart showing the offset arrangement of the mitral valve (MV) and tricuspid valve (TV) which produces the so-called muscular atrioventricular septum (∗) and the deep in folding (dotted lines) of the atrial wall superior and inferior to the floor of the oval fossa. IVC = inferior vena cava; SVC = superior vena cava.

Reprinted with permission from Sánchez-Quintana et al. (11).

Follow-Up

Approximately 1 month later, the patient was seen in the outpatient clinic and had no adverse clinical sequelae.

Conclusions

Appreciation of the anatomic relationship between the interatrial septum and the transverse pericardial sinus is crucial to the interventional cardiologist or electrophysiologist during transseptal puncture. Identification and puncture of the true IAS may aid in avoidance of complications including transgression into the pericardial space, aorta, or left ventricle.

Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Appendix

Supplemental Video 1

RAO 40° projection of contrast injection following transseptal puncture demonstrates simultaneous contrast flow into the left ventricle and extravasation into the transverse pericardial space.

Supplemental Video 2

LAO 50° projection of contrast injection following transseptal puncture demonstrates contrast flow into the transverse pericardial space.