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© 2003 European Association of Cardio-Thoracic Surgery
Preliminary experience in mitral valve repair using the Cosgrove–Edwards annuloplasty ringDepartment of Cardiac Surgery, Villa Torri Hospital, viale Filopanti, 12 – 40126 Bologna, Italy.
* Corresponding author. Via Pignolini 5, 37019 Peschiera d/G, Verona, Italy. Tel.: +39-348-3402078; fax: +39-051-253854 Received November 21, 2002; received in revised form February 19, 2003; accepted March 6, 2003
There is a wide range of annuloplasty systems available now. However, controversy concerning the choice of annuloplasty device persists. We analyzed our preliminary experience in mitral valve repair using the Cosgrove–Edwards annuloplasty ring. To correct their mitral insufficiency (MI), 118 consecutive patients (mean age, 60.4±15.1 years) underwent mitral repair using this annuloplasty device. NYHA functional class 3 or 4 were present in 86.4%. Degenerative heart disease was the cause of MI in 36.6% of the patients, ischemic heart disease in 25.4%, Barlow's disease in 17.8%, and idiopathic dilated cardiomyopathy in 7.6%. Mitral surgical procedures included quadrangular resection and sliding of the posterior leaflet, posterior leaflet decalcification, anterior leaflet repair, the edge-to-edge technique, and chordal repair. Mean follow-up was 25.1±14.0 months. There were four in-hospital non-valve-related cardiac deaths, and one in-hospital non-cardiac death. No cases of systolic anterior motion were observed. NYHA functional class improved from 3.3±0.7, before repair, to 1.3±0.6, at follow-up (  ), MI from 3.6±0.5 to 0.5±0.6 ( ), and left ventricular ejection fraction from 52.0±12.2% to 55.4±12.0% ( ). Three-year actuarial rates of survival, freedom from thromboembolism, and freedom from mitral reoperation were 96.9, 97.9, and 96.4%, respectively. The Cosgrove–Edwards annuloplasty ring does not combine with systolic anterior motion. It minimizes MI secondary to all causes, and preserves left ventricular function.
Key Words: Mitral insufficiency; Mitral valve repair; Annuloplasty ring
The Cosgrove–Edwards annuloplasty ring (DCIII-E ring) (Edwards Life Sciences, Irvine, CA, USA) is a ‘C’-shaped universally flexible band (partial flexible ring) that provides, in the mitral valve position, a measured plication of the posterior annulus. No sutures are placed along the anterior annulus [1]. Reconstruction of the mitral annulus from real-time three-dimensional echocardiographic images confirmed preserved non-planar shape and sphincter mechanism of the mitral annulus after mitral valve repair with the DCIII-E ring, according to the very good clinical results reported [1,2]. The DCIII-E ring, as well as other partial flexible rings, could minimize mitral insufficiency (MI) and left ventricular outflow tract obstruction caused by systolic anterior motion of the anterior mitral leaflet, and keep left ventricular function. The purpose of this retrospective study was to verify these hypothetical advantages of partial flexible annuloplasty rings by our preliminary experience in mitral valve repair using the DCIII-E ring.
After starting with the use of the DCIII-E ring at our Department (September 1998), all of the 118 patients with MI who underwent mitral valve repair by October 2002 (40.4% of the overall mitral surgery) had this ring as an annuloplasty device. No other rings were implanted during this time. Mean age was 60.4±15.1 years (range, 12–83 years). Seventy-nine (66.9%) patients were men. Fifty-seven (48.3%) patients were in preoperative New York Heart Association (NYHA) functional class 4, 45 (38.1%) in NYHA functional class 3, and 16 (13.6%) in NYHA functional class 2. Sixty-seven (56.8%) patients were in sinus rhythm, 48 (40.7%) in atrial fibrillation, and three (2.5%) paced. The surgical priority, graded according to The Society of Thoracic Surgeons, was elective in 91 (77.1%) patients, urgent in 23 (19.5%), and emergency in four (3.4%) [3]. Thirty-four (28.8%) patients had EuroSCORE 6 or higher (95% confidence interval (CI) for expected mortality, 10.9–11.5%) [4].
Preoperative echocardiographic examination was always performed. Severity of MI was graded echocardiographically by 5-point scale using color-Doppler flow images and flow direction in the pulmonary veins: According to preoperative clinical and echocardiographic data and surgical findings, causes of MI were degenerative heart disease in 43 (36.6%) patients, ischemic heart disease in 30 (25.4%), Barlow's disease in 21 (17.8%), idiopathic dilated cardiomyopathy in nine (7.6%), associated degenerative and ischemic heart diseases in four (3.4%), infective endocarditis in four (3.4%), congenital heart diseases in three (2.5%), rheumatic disease in three (2.5%), and trauma in one (0.8%) patient. Left ventricular ejection fraction in the patients with ischemic heart disease was 38.0±10.7%, and in those with idiopathic dilated cardiomyopathy 28.0±14.2%. Mechanisms responsible for MI were confirmed by transesophageal echocardiographic examination early before sternotomy, and by intraoperative direct evaluation of pathological mitral valves (Table 1).
The surgical technique for the Cosgrove–Edwards annuloplasty ring implantation at the mitral site was performed as described by Cosgrove et al. [1]. Sixteen (13.5%) 34 mm-, 39 (33.0%) 32 mm-, 51 (43.2%) 30 mm-, 10 (8.6%) 28 mm-, and two (1.7%) 26-mm-annuloplasty rings were used. Appropriate repair techniques were directed to specific structures of the mitral valve apparatus (Table 2) [1,5–8]. In 62 (52.5%) patients we performed 72 concomitant surgical procedures: myocardial revascularization, 34; left atrial internal microwave ablation for recent atrial fibrillation, 26 (at our Department, this procedure is performed as of May 2001); tricuspid valve repair, 6; aortic valve replacement, 4; and closure of ostium secundum type atrial septal defect, 2. Surgical procedures per patient were 2.2. All cardiac operations were performed through standard median sternotomy, with cardiopulmonary bypass and moderate hypothermia (30 °C). Myocardial protection was achieved with either crystalloid or blood cardioplegia delivered antegrade, or antegrade and retrograde. Topical cooling was routinely used.
Echocardiographic evaluation to confirm the competence of mitral valve after repair was carried out, intraoperatively, by transesophageal approach and, at discharge and follow-up, by transthoracic approach. Warfarin anticoagulation was started on in all patients the first postoperative day, and stopped 3e months from cardiac operation in the patients with persistent sinus rhythm and left ventricular ejection fraction greater than 35%. During anticoagulant therapy, the international normalized ratio was maintained within a range of 2.5–3.5 according to The American Heart Association [9]. The patients who underwent combined myocardial revascularization had a platelet-inhibitor drug in addition. Survivors were followed up directly in our outpatient clinic. Mean clinical and echocardiographic follow-up (100% complete) was 25.1±14.0 months (246.8 cumulative patient-years), with a range of 1–49 months and a median of 23.5 months. Deaths and complications were defined according to The Society of Thoracic Surgeons and The American Association for Thoracic Surgery [10]. 2.1. Statistical methods Values are expressed as mean±standard deviation, or as percentage. Continuous variables were compared by the Student's t-test. Statistical significance was assumed for a P-value less than 0.05. Non-parametric estimates of morbid events were obtained by the Kaplan–Meier survival analysis method. Statistical analysis was performed using MINITAB release 13 statistical software (MINITAB Inc., State College, PA).
There were five (4.2%) in-hospital deaths. A 79-year-old woman with severe rheumatic heart disease causing MI and pulmonary hypertension (systolic pulmonary artery pressure, 72 mmHg) died of right heart failure. Of two patients with chronic ischemic left ventricular dysfunction (left ventricular ejection fraction less than 30%), the former died of refractory ventricular fibrillation due to myocardial ischemia in second postoperative day, the latter of multiorgan failure 22 days after operation. Complete myocardial revascularization has been performed in both the patients. Of two patients with an evolving myocardial infarction and operated on in emergency, the former (an 83-year-old woman with acute rupture of the posterior papillary muscle) died of low cardiac output 3 days after cardiac operation, the latter on the seventh postoperative day owing to acute rupture of chronic abdominal aortic aneurysm (intra-aortic balloon pump had been used to try treating preoperative hemodynamic instability).
In 33 (29.2%) of the 113 discharged patients were recorded any of the following in-hospital postoperative complications: paroxysmal atrial fibrillation, 27 (among the 93 survivors in sinus rhythm early after cardiac operation); pericardiocentesis due to pericardial effusion, 3; respiratory failure, 3; sternal diastasis needing sternal reconstruction, 3; perioperative myocardial infarction, 2; renal failure (serum creatinine concentration Early after cardiac operation, in all patients with any residual MI (55, 46.6%), mitral regurgitant jet areas were always less than 2.0 cm2. No cases of left ventricular outflow tract obstruction were observed, or early after mitral repair or at follow-up. Four (3.5%) patients died during follow-up: two patients of malignant pulmonary disease, one of myocardial infarction, and one 80-year-old man of stroke on a thromboembolic basis early after suspension of anticoagulant therapy. At 16 months from mitral repair, thromboembolic disease caused left arm monoplegia in a 78-year-old woman with atrial fibrillation in treatment with a platelet-inhibitor drug because of warfarin intolerance. Four (3.5%) patients underwent mitral valve reoperation (mitral valve replacement): two patients for persistent hemolysis causing severe anemia, one for symptomatic worsening due to recurrent MI of grade 3+, and one for infective endocarditis following hip joint prosthesis replacement at 11 months from cardiac operation. Three-year actuarial rates of survival, freedom from thromboembolism, and freedom from mitral reoperation were 96.9% (95% CI 93.5–100%), 97.9% (95% CI 95.1–100%), and 96.4% (95% CI 92.9–99.9%), respectively (Fig. 1).
At follow-up, MI decreased significantly from 3.6±0.5 before repair to 0.5±0.6 ( ), according to significant improvement of NYHA functional class (3.3±0.7 to 1.3±0.6, ) and left ventricular ejection fraction (52.0±12.2% to 55.4±12.0%, ) (Fig. 2).
Mitral annulus is saddle-shaped, higher at the anterior and posterior segments and lowest at the commissures. This shape helps the anterior mitral annulus softly surround the left ventricular outflow tract. Besides, mitral annulus undergoes periodical changes in size and shape throughout the cardiac cycle, contracting during systole. This sphincter mechanism increases the depth of coaptation of the leaflets during systole and improves the annular orifice area during diastole. Systolic reduction of mitral annular orifice area is due to contraction of entire posterior annulus. In addition, the anterior annulus is an even more dynamic component of the mitral apparatus [1,2,11]. Pathological dilatation of the mitral annulus occurs along the attachment of the posterior leaflet, whereas the distance between the fibrous trigones anteriorly remains stable [1,2]. Furthermore, clinical studies have showed that durability of mitral valve repair is enhanced by use of an annuloplasty system [12]. All these notions should be taken into account before performing mitral valve repair and using any eventual annuloplasty technique. However, there is considerable controversy concerning the choice of annuloplasty system. The ideal annuloplasty device should maintain the non-planar shape and physiological motion of the mitral annulus during cardiac cycle. In addition, it should correct the dilatation of the posterior annulus and preserve the function of anterior mitral annulus avoiding potential deformity of the aortic valve. Last but not least, the ideal device should prevent from increasing antero-posterior diameter of mitral annulus. Although, at present, there is a wide range of annuloplasty systems available, the most important structural characteristics of an ideal annuloplasty system are not as yet determined. Carpentier introduced the concept of annuloplasty with rigid prosthetic ring in 1969 [13]. Duran and Ubago developed a flexible prosthetic annuloplasty ring in 1976 [14]. Results with both these prostheses were good. However, three-dimensional echocardiographic studies showed that, in patients with a flexible ring, the mitral annulus had a non-planar configuration and mitral annular area changed during cardiac cycle [1,2,15], whereas in patients with a rigid ring, the mitral annulus had a planar configuration and mitral annular area was effectively unchanged during the cardiac cycle [15]. Mitral annular inflexibility due to rigid prostheses has been considered to contribute to the mechanism of dynamic left ventricular outflow tract obstruction after mitral valve repair or replacement [16]. A recent analysis of three-dimensional movement of the mitral valve annulus indicated that preserving mitral annular flexibility may prevent left ventricular outflow tract obstruction [17]. Importance of flexible annuloplasty ring to preserve left ventricular function is debatable at present. Comparative animal studies showed that left ventricular performance is not significantly altered with either rigid or flexible annuloplasty ring [18]. Otherwise, other comparative human studies indicated that patients with flexible annuloplasty ring have better left ventricular performance than patients with a rigid annuloplasty ring [19]. Actually, it is difficult to quantify the clinical importance of this hemodynamic advantage. Partial (prosthetic or biological – strip of bovine or autologous pericardium) annuloplasty ring has the merits of correction of selective posterior annular dilatation and avoidance of potential deformity of the aortic valve [1,2,20]. A recent study comparing partial with complete flexible annuloplasty rings showed that the partial flexible ring preserves physiologic mitral annular folding dynamics [21], which might be important for prevention of left ventricular outflow tract obstruction, and for long-term valve function. In brief, hypothetical superiorities both of flexible to rigid, and partial to complete ring are difficult to demonstrate with certainty. However, there have been no studies demonstrating the reverse. Therefore, in our clinical practice, we systematically adopted the DCIII-E ring as an annuloplasty system. According to this preliminary experience with the DCIII-E ring, no in-hospital deaths were valve-related. Among the four patients who died during follow-up, there were two non-cardiac deaths, and one non-valve-related cardiac death. Anticoagulation therapy promoted gradual healing-in of the exposed cloth and sutures. Our strategy of thromboembolic prevention was efficacious. In fact, the two patients who experienced a thromboembolic event were high-risk patients for thromboembolism, independently from previous mitral surgery. In the two patients who underwent mitral valve reoperation for severe hemolytic anemia, a central mitral regurgitant jet causing moderate MI has been shown by transesophageal echocardiographic imaging. This regurgitant jet was perpendicular to mitral annulus in one patient, and directed towards the implanted annuloplasty ring in the other. MI was well controlled within grade 2+ in all survivors except one. Mechanism of recurrent MI (of grade 3+) in this patient was limited bulging of the free margin of the anterior mitral leaflet into the left atrium. In three patients, mitral valve replacement was performed without explanting the annuloplasty ring. In the fourth patient, who underwent mitral valve reoperation for infective endocarditis, the DCIII-E ring was explanted to perform a radical surgical toilette of mitral valve apparatus. MI was well controlled even in dilated cardiomyopathy, but eventual changes in antero-posterior diameter of mitral annulus were not calculated. When we decide on the surgical strategy for patients with MI, we evaluate carefully the mitral valve morphology and the mechanism of MI, no matter their age, preoperative condition, surgical priority, or predicted operative time. This policy could be hazardous, but we trust in the superiority of the mitral valve repair (when possible) compared with the mitral valve replacement. The DCIII-E ring does not combine with the left ventricular outflow tract obstruction, minimizes residual and recurrent MI, and preserves left ventricular function. It is a valid and safe option for correction of pure MI secondary to all causes, at least on a short-term basis. doi:10.1016/S1569-9293(03)00056-2
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Abstract
1. Introduction
or trivial, 
, 
, 
to severe, and 
. Preoperative MI was 4+ in 71 (60.2%) patients and 3+ in 47 (39.8%). 
mg/dl), 2; reoperation due to bleeding, 1; and acute cholecystitis, 1. Mean postoperative hospital stay was 8.7±2.3 days. 
