Interactive Cardiovascular and Thoracic Surgery 2:501-502(2003)
© 2003 European Association of Cardio-Thoracic Surgery
Combined mitral valve repair, LVOT myectomy and left atrial cryoablation therapy
U.T. Opfermann,
N. Doll*,
T. Walther and
F.W. Mohr
Department of Cardiac Surgery, Heartcenter Leipzig GmbH, University of Leipzig, Strümpellstrasse 39, 04289 Leipzig, Germany
* Corresponding author. Tel.: +49-341-865-1421; fax: +49-341-865-1452
dolln{at}medizin.uni-leipzig.de
Received May 5, 2003;
received in revised form June 2, 2003;
accepted June 13, 2003
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Abstract
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Asymmetric septal hypertrophy (ASH) is a common cause of left ventricular (LV) outflow tract obstruction. Mitral valve (MV) regurgitation is present in 30% of those patients as well as biatrial enlargement. Furthermore, paroxysmal or chronic atrial fibrillation (AF) occurs in up to 22%. Two male patients were admitted for shortness of breath and decreased physical ability. Hypertrophic obstructive cardiomyopathy (HOCM) with ASH, severe MV regurgitation and chronic AF were diagnosed in both patients; present for 8 years in patient 1 and 1 year in patient 2. Both received MV annuloplasty, transaortic septal resection using the modified Morrow et al.'s technique and left atrial cryoablation therapy via median sternotomy. Intraoperative measurement revealed no residual gradients and competent MV, furthermore, both patients were discharged in sinus rhythm.
Key Words: Valve disease; Cardiac-other; Electrophysiology-arrhythmias
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1. Introduction
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Hypertrophic obstructive cardiomyopathy (HOCM) is characterized by idiopathic marked left ventricular (LV) hypertrophy. The incidence ranges from 0.02 to 0.2% [1]. Asymmetric septal hypertrophy (ASH) is a common cause of LV outflow tract obstruction. Mitral valve (MV) regurgitation is present in 30% of those patients as well as biatrial enlargement. Furthermore, paroxysmal or chronic atrial fibrillation (AF) as a result of increasing left atrial size occurs in up to 22%, which seems to be associated with increased HOCM-related mortality [2]. We describe two patients who received a combined approach including LVOT myectomy, MV repair and cryoablation therapy.
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2. Materials and methods
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2.1. Patient 1
A 52-year-old male patient with HOCM presented with shortness of breath at moderate physical activity and slight peripheral edema. Chronic AF was present for 8 years. Echocardiography revealed severe LV hypertrophy with interventricular septal diameter of 27 mm and a LVOT pressure gradient of 40 mmHg, third degree MV incompetence due to a dilation of the mitral annulus, moderate tricuspid valve incompetence, normal ejection fraction and preserved RV function.
2.2. Patient 2
A 67-year-old male patient presented with palpations and decreased physical ability. Seven days ago, the patient suffered first time cardiac decompensation with pulmonary edema. HOCM was evident for 14 years and chronic AF for 1 year refractory to medical treatment. Echocardiography revealed a hypertrophied left ventricle with normal ejection fraction, interventricular septal diameter of 27 mm, third degree MV incompetence and moderate tricuspid valve incompetence caused by annular dilatation. Left heart catheterization revealed a peak gradient of 105 mmHg.
Both operations were performed using median sternotomy and total cardiopulmonary bypass. After transverse aortotomy, longitudinal resection of a substantial portion of the interventricular septum according to the technique described by Morrow et al. [3] was performed in both patients. Then cryoablation was performed via a left atriotomy using the SurgiFrostTM System (Cryocath Technologies Inc., Quebec, Canada). Argon gas was used as the refrigerant. After having reached a temperature at the tip of the device of –40 °C, the counting of the adjusted cycle length was started. The pre-selected target catheter tip temperature was –160 °C and the duration of cryo-application was 60 s after the target temperature had been achieved. A continuous lesion line was created extending from the inferior aspect of the posterior mitral leaflet (P3) to the left lower pulmonary vein. Separate lesion lines were created between the left upper and lower pulmonary vein orifices, between the left and right upper pulmonary vein orifices via the left atrial roof, and between the right upper and lower pulmonary vein orifices connected to the atriotomy.
MV repair was accomplished by ring annuloplasty (Patient 1: Carpentier Edwards, 30 mm; Patient 2: Cosgrove, 34 mm). Due to prolapse of the anterior leaflet in Patient 2, chordal transfer was performed from the P3 to A3 segment with partial excision of the P3 segment. Intraoperative transesophageal echocardiographic assessment of tricuspid incompetence in Patient 1 showed mild to moderate regurgitation and was, therefore, not corrected.
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3. Results
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After weaning from cardiopulmonary bypass, invasive blood pressure monitoring showed no gradient between the left ventricle and the ascending aorta. Complete restoration of MV competence was confirmed by intraoperative TEE in both patients. They were discharged in stable sinus rhythm and were in NYHA functional class 1 at 3 months follow-up.
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4. Discussion
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One-third of patients with HOCM and septal hypertrophy have additional MV regurgitation due to anterior displacement of papillary muscles and MV leaflets. The anterior leaflet is subjected to drag forces resulting in systolic anterior motion (SAM) contact with the hypertrophied septum causing subaortic obstruction [4,5]. The SAM of the anterior leaflet prevents coaptation with the posterior leaflet. Eccentric MV incompetence is frequently present in patients with SAM. The LVOT pressure gradient occurs virtually simultaneously with the onset of anterior leaflet–septal contact.
Patients (5–15%) with HOCM develop chronic or paroxysmal AF. Despite an increased risk for thromboembolic events, the loss of atrial contraction results in a decline in stroke volume and cardiac output of 20–35 %, especially when diastolic stiffness is present [6]. In these patients, surgical therapy combining myectomy with MV reconstruction and curative surgical treatment of AF to restore the atrial contribution to ventricular filling and output is especially advantageous.
Introduced by Cox et al. [7] as the Maze procedure, surgical treatment of AF has undergone a permanent evolution towards less invasive and time sparing techniques such as left atrial cryoablation.
Cryoenergy produces a lesion that generally preserves the integrity of adjacent structures such as the circumflex artery, esophagus and the pulmonary veins [8]. If the lesions are transmural and no gaps of conduction occur between the ablation lines, sinus rhythm can be restored permanently in up to 95% of patients, sometimes with additional drug therapy needed [9].
In summary, patients with HOCM and multiple cardiac pathologies, substantially profit from one-step surgical treatment of mitral regurgitation, interventricular septal hypertrophy and AF. Based on our good outcome, the complete approach restoring almost physiological cardiac function can be recommended.
doi:10.1016/S1569-9293(03)00129-4
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Abstract
1. Introduction