Scientific letter Safety of MitraClip Implantation in Patients With a Left Ventricular Endocardial Lead for Cardiac Resynchronization Therapy Through the Interventricular Septum

To the Editor,

Cardiac resynchronization therapy (CRT) is a widely-accepted therapeutic strategy used in a large number of patients with heart failure due to left ventricular (LV) dysfunction and asynchrony.¹ Although the coronary sinus is the access of choice for the LV lead, it cannot be used in up to 10% of patients because of anatomical difficulties.² An alternative access has therefore also been proposed, passing through the interventricular septum.³

We report 2 cases of patients with severe LV failure who had not responded to CRT with the LV endocardial lead implanted through the interventricular septum. Both had severe mitral regurgitation (MR) and underwent MitraClip implantation.

The patients were aged 67 and 73 years, with nonischemic dilated cardiomyopathy, LV ejection fraction of 15% and 20%, respectively, and grade III-IV functional MR (FMR). In the electrocardiograms, complete left bundle branch block was observed, leading to LV asynchrony.

After several admissions for decompensated heart failure, the patients were readmitted for implantable cardioversion/defibrillator placement and CRT. Initially, an attempt was made to implant the LV lead with a conventional approach in the coronary sinus, but, because of the anatomical features of this structure, the LV endocardial lead had to be implanted by interventricular septal puncture. During the following year, further admissions to hospital were required for decompensated heart failure. Given the presence of severe FMR and, after confirmation that the patients were appropriate candidates, a MitraClip was implanted. Technical precautions were taken, such as avoiding going any lower than necessary within the LV when capturing the leaflets, through careful monitoring of movements, both by echocardiography and by fluoroscopy (Figure 1 and Figure 2). A decrease of FMR from grade III-IV to grade I-II was achieved with approximation of the A2/P2 segments with a single mitral clip, without any complications or interference from the endocardial LV lead (Figures 2C and 2F). Transeptal puncture was performed at the optimal site for implanting the MitraClip, while still ensuring good device handling (Figure 2A). In addition, the distance between the endocardial LV lead and the mitral leaflets in diastole was measured with particular care (Figures 2A and 2B). With follow-up currently of 1 year and 3 months, respectively, the outcome has been favorable with significant improvement in the patients’ functional grade.

Figure 1.

Fluoroscopic images. A, Left oblique anterior view showing the TSP needle and an angioplasty guide catheter toward the left superior pulmonary vein; CRT is the cardiac resynchronization lead passing from the right ventricle through the interventricular septum to the lateral wall of the left ventricle; ICD is the lead for the implantable cardioverter/defibrillator device. B, C, and D, Right oblique anterior view showing the different phases of MitraClip intervention with positioning, capture, and release, respectively, and its position relative to the CRT cable. CRT, cardiac resynchronization therapy; ICD, implantable cardioverter/defibrillator; MC, MitraClip; TSP, transseptal puncture.

Figure 2.

Transesophageal echocardiography images during the intervention. A and B, 4-chamber view (0°); relationship of the closed and open mitral valve and with the CRT lead. Panel A shows the distance from the point of transeptal puncture to the line of fusion of closure of the mitral leaflets and the distance from the lead to the mitral plane. Panel B shows the measurements of the A2/P2 leaflets, respectively. C, bicommissural view (70°); severe mitral regurgitation toward the left atrium can be observed. D, 3-dimensional image of the MitraClip, perpendicular to A2/p2 leaflets of the mitral valve. E, outflow tract view (120°). F, bicommissural view (70°); capture of the mitral leaflets (E) and release of the clip (F), with minimal residual regurgitation, and its position relative to the CRT lead. CRT, cardiac resynchronization therapy.

It is known that 30% to 40% of these patients do not respond to CRT and, in many cases, if severe FMR is present (as occurs in approximately one third of patients), the next step is MitraClip placement (Abbott Vascular). This technique has been shown to be effective at reducing symptoms and readmission rates in these patients.^4,5

The PERMIT-CARE study included 51 symptomatic patients who did not respond to CRT. Of these, 46% had moderate-severe FMR and 54% had severe FMR. The decrease in FMR after MitraClip placement was accompanied by decreases in LV end-diastolic and end-systolic volumes at 6 to 12 months and improvement in functional class.⁴

The combination of these 2 therapies (CRT and MitraClip) is becoming increasingly widespread, given the importance of reducing FMR in patients who do not respond to CRT, and therefore there will be an increasing number of patients in whom the coronary sinus cannot be used for LV access. To our knowledge, no articles have been published on this combination of MitraClip (and corresponding safety) with CRT using endocardial LV leads with interventricular septal access. Our experience in this context is therefore particularly relevant.

CONFLICTS OF INTEREST

R. Estévez-Loureiro and C. Garrote-Coloma are Abbot consultants for MitraClip.

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