12

TRANSSEPTAL
LEFT HEART INTERVENTIONS

MEHUL B. PATEL, TAHMEED CONTRACTOR, SAMIN K. SHARMA

Transseptal catheterization (TSC) was first introduced in 1959 by Ross and Cope, and later modified by Brockenbrough and Mullins.^1,2 There was a significant decline in the utilization of this technique after the introduction of the balloon flotation pulmonary artery catheter in 1970 by Swan and Ganz.³ With the advent of mitral and aortic valvuloplasty along with catheter ablation for left atrial tachycardia and left-sided accessory pathways, there was a renewed interest in transseptal catheterization worldwide. Transseptal catheterization has seen a further resurgence because of catheter ablation for atrial fibrillation and cardiac interventions on the left side of the heart.

Due to the limited working space of the fossa ovalis and the potential for life-threatening complications, the operator must have a thorough knowledge of the anatomy of the interatrial septum (IAS) along with the contraindications of the procedure.^4,6 The fundamental principles of transseptal catheterization along with the indications, contraindications, and complications are described in accompanying chapters in this book. An elaborative description of individual procedures is beyond the scope of this chapter. This chapter has detailed the salient technical steps of left heart interventions that require transseptal access and focuses on the variations in transseptal puncture (TSP) sites. Left atrial appendage (LAA) closure with the WATCHMAN device (Atritech, Inc, Plymouth, MN) is discussed in Chapter 13. Most of these procedures are fairly complex and require real-time transesophageal echocardiography (TEE) or intracardiac echocardiography (ICE) guidance for transseptal puncture, catheter manipulation, and precise placement of devices.

Left Heart Interventions
via Transseptal Puncture

Transseptal catheterization plays a pivotal role for mitral valve interventions. The individual procedures are described in Charts 12.1 and 12.2, which are supported by two schematic representations, Figures 12.1 and 12.2.

Percutaneous Transluminal Mitral Commissurotomy (PTMC) or Mitral Valvuloplasty

Indications

Moderate to severe symptomatic mitral stenosis with a favorable mitral anatomy in the absence of a left atrial (LA) clot.

Pre-catheterization Planning

All patients should undergo a regular transthoracic echocardiogram (TTE) along with a transesophageal echocardiogram (TEE) using standard views to rule out left atrial or left atrial appendage thrombus prior to the procedure. The mitral valve should be evaluated and scored using the standard Wilkins scoring system for risk stratification.

Hardware

Standard transseptal catheterization hardware as described in Chapter 5is used. An Inoue balloon should also be available, along with such auxiliary instruments as a 14 F dilator, a spring wire, a preshaped left ventricular (LV) stylet with a pre-marked syringe for balloon inflation, and Vernier calipers to measure the balloon waist diameter.

Procedure

The salient steps of percutaneous transluminal mitral commissurotomy are shown in Chart 12.1.^7–14

Problems and Precautions

The precautions and special circumstances are described in Chapter 15 (“Complications of Transseptal Catheterization”).

Current Status

PTMC is a well-established procedure with efficacy equivalent to closed mitral commissurotomy. It remains the treatment of choice for stenotic mitral valves without commissural calcification or extensive subvalvular fusion.

Percutaneous Direct Edge-to-Edge Mitral Valve Repair (“The Percutaneous Alfieri Stitch”)

Indications

Symptomatic severe mitral regurgitation with a favorable mitral valve anatomy in a patient deemed at an unacceptably high risk for surgical correction. A logistic EuroSCORE predicted surgical mortality of greater than 20% is considered as a reasonable indication for percutaneous intervention.

All patients should undergo a TTE along with a TEE to assess the mitral valve morphology. The working views include a regular short-axis TEE at the base, a long-axis four-chamber view, and a mid-esophageal five-chamber view. The fluoroscopic views include the standard fluoroscopic views for TSR The device deployment and withdrawal are done strictly using realtime TEE imaging.¹⁵

Hardware

The hardware consists of the regular TSP hardware, along with the clip and the clip-delivery system (CDS). The Evalve repair device (Abbott Laboratories, Abbott Park, IL) contains a single-plane steerable guide catheter and a CDS, which includes a dual-plane steerable sleeve, a clip delivery catheter, and a clip (MitraClip, Abbott Laboratories, Abbott Park, IL).

Procedure

The salient steps for direct mitral valve repair are shown in Chart 12.2 and illustrated in Figure 12.1. In 40% of patients an additional clip may be required to achieve success.

Current Status

The clips for mitral valve repair are still in clinical trials. Following enrollment completion of the EVEREST trials, patients who receive the MitraClip are being treated in a continued access registry called REALISM.

Mitral Paravalvular Leak Repair

Indications

Symptomatic paravalvular leak after prosthetic mitral valve replacement.

Paravalvular leak can present early or late. Clinical presentation can be with heart failure or incessant hemolysis. The defect can be small or large, and it can be circular, crescent, or tunnel-like in shape.

Pre-catheterization Planning

All patients should have a regular TTE along with TEE to assess the mitral valve morphology. The fluoroscopic views include the standard fluoroscopic views for TSP, along with 30° left anterior oblique (LAO-30) and 30° right anterior oblique (RAO-30) projections.

Hardware

The hardware for a mitral paravalvular leak repair consists of a Judkins right 4.0 catheter, a 0.035 stiff, straight Terumo Glidewire (Terumo Medical Corporation, Somesrset NJ), a patent ductus arteriosus (PDA) occluder, an Amplatzer PDA device (AGA Medical Corporation, Plymouth, MN), rigid coils, and small-sized atrial septal defect (ASD) closure devices.

Procedure

Vascular Approach. For leaks close to the IAS, an internal jugular approach is best suited for crossing the defect. For leaks further away from the IAS, a femoral approach is preferred.

Crossing the Defect with Leak. Due to high-pressure turbulent flow across the paravalvular leak, it may be difficult to cross the defect from the LA to the LV (Figure 12.2

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