Surgical treatment of asymptomatic and mildly symptomatic mitral regurgitation.

OBJECTIVE: The purpose of this study was to review the risk-benefit ratio of mitral valve repair in patients with severe mitral regurgitation and no or mild symptoms. METHODS: From January 1989 to December 1994, 584 patients were operated on for mitral regurgitation. Of these, 175 patients were in New York Heart Association class I or II with grade 3 to 4 isolated chronic mitral regurgitation. They comprise our study population. Mean age was 51.3 +/- 14.3 years. Principal causes of mitral regurgitation were degenerative in 128 (73%) and rheumatic in 26 patients (15%). Leaflet prolapse was the mechanism responsible for regurgitation in 152 patients (86%). Mitral valve repair was performed in 174 patients, and one patient required initial valve replacement. Mean follow-up was 34.3 +/- 18.8 months. RESULTS: Three patients died, for an overall mortality of 1.7%. Five patients were reoperated on, for an actuarial freedom from reoperation of 97.0% +/- 0.8% at 5 years. Actuarial freedom from thromboembolism and endocarditis was 96.3% +/- 1.7% and 99.4% +/- 0.6%, respectively, for an event-free survival of 91.0% +/- 2.0% at 5 years. Left atrial diameter decreased from 54.3 +/- 11.6 mm to 43.6 +/- 10.5 mm (p < 0.001). Left ventricular end-systolic and end-diastolic diameters decreased from 40.0 +/- 6.8 mm and 64.8 +/- 7.0 mm to 34.6 +/- 6.7 mm (p < 0.001) and 52.7 +/- 7.4 mm (p < 0.001), respectively. Mean residual mitral regurgitation was 0.44 +/- 0.6. CONCLUSION: Mitral valve repair for chronic mitral regurgitation in patients having mild or no symptoms was performed with low mortality and morbidity, good valve function, and preserved late left ventricular performance. Early repair may be advocated on the basis of severity of regurgitation and valve repairability, regardless of symptoms.

Beyond hyperkalemia: beta-blocker-induced cardiac arrest for normothermic cardiac operations.

BACKGROUND: Four experimental protocols were carried out to assess the ability of esmolol to induce and maintain reversible cardiac arrest under continuous normothermic (37 degrees C) perfusion. METHODS AND RESULTS: In the first protocol, 8 perfused rat hearts were subjected to 20, 60, 90, and 120 minutes of esmolol arrest, after which positive and negative first derivative of pressure, heart rate, left ventricular developed pressure, and left ventricular end-diastolic pressure were evaluated. Arrest was achieved 45 to 60 seconds after beginning the infusion of esmolol. Mechanical arrest was achieved before electrical arrest. In the second protocol, dose-response curves were obtained using isolated (Langendorff) rat and rabbit (n = 6) hearts. The concentrations of esmolol varied from 0.084 to 6.7 mmol/L and from 0.12 to 1.45 mmol/L in the rat and rabbit heart experiments, respectively. In the third protocol, the effects of 20 minutes of normothermic (37 degrees C) ischemia on the function of isolated rat hearts perfused with esmolol-containing Krebs solution were compared with those using high-potassium (25 mmol/L) Krebs solution. Group A subjects (n = 9) received the ischemic injury after being perfused (and arrested) for 20 minutes with either esmolol or potassium (KCl, 25 mmol/L). Group B subjects (n = 10) received the same ischemic insult before being perfused with either esmolol or potassium. Esmolol-treated hearts showed better recovery than those receiving potassium, in terms of +/- dP/dt (p < 0.01), left ventricular systolic pressure (p < 0.01), and left ventricular developed pressure (p < 0.009). Finally, the fourth protocol was done to evaluate the effects of esmolol in a clinically relevant experimental model. Pigs were divided into esmolol (n = 6) and potassium (n = 5) groups and subjected to normothermic cardiopulmonary bypass and a 1-hour period of cardiac arrest. Twenty minutes after stopping infusion of the cardioplegic agents, all animals were weaned off bypass. There were no statistically significant differences between the groups. CONCLUSIONS: Esmolol hydrochloride can be used as effectively as potassium for inducing and maintaining predictable and reversible cardiac arrest during normothermic cardiac operations.

Morphologic classification of the mitral papillary muscles.

BACKGROUND AND AIMS OF THE STUDY: Mitral homograft replacement requires a good knowledge of the anatomy of the papillary muscles. Clinical experience with mitral homografts has revealed an as yet unexplored aspect of the morphology of the mitral subvalvular apparatus, that is correspondence between papillary muscle sub-divisions and chordal attachment to the leaflets. METHODS: To further our understanding we subjected 65 normal hearts to close scrutiny which confirmed our perioperative observations. RESULTS: We could establish a classification based on the ways that the papillary muscles relate to the leaflets via the chordae. Four types are described. In type I the papillary muscle is single. In type II the papillary muscle has two heads, one of which sends chordae exclusively to the posterior leaflet. In type III the papillary muscle is also divided, one head supporting the commissural area exclusively. Type IV PM resembles type III but is distinguished from it in the way that the head supporting the commissure is very short. In this type the different heads also originate at different levels on the ventricular wall from the apex to the base.

[Initial results of mitral valvuloplasty using the Physio-Carpentier-Edwards ring]. / Résultats préliminaires de la plastie mitrale avec l'anneau physio-carpentier-edwards.

The Physio-Carpentier-Edwards ring is a new prosthetic ring developed to allow mitral annuloplasty associating remodelling and flexibility of the native mitral annulus. The object of this study was to assess the feasibility and reliability of mitral valvuloplasty with the Physio ring. Between December 1992 and October 1995, 100 patients with an average age of 56.8 years suffering from mitral insufficiency underwent mitral valvuloplasty with a Physio ring. The mitral insufficiency was degenerative in 94% of cases. The degree of regurgitation was scored 3+ or 4/+4/+ in 94 patients. Mitral valve prolapse was observed in 83 patients. Mitral reconstruction was undertaken using Carpentier's techniques. One patient died in the immediate postoperative period. Two patients were reoperated for valve replacement because of systolic anterior motion (SAM). One patient had SAM which regressed with medical treatment. There were no deaths after the hospital period. There were no late reoperations of thrombo-embolic complications. The average follow-up period was 19 +/- 8 months; 77 patients were followed up for over 1 year and all underwent control Doppler echocardiography. Sixty-one patients had no residual mitral insufficiency: 15 patients had grade 1/4 regurgitation and one patient had grade 2/4 regurgitation. The average mitral valve surface area was 2.8 +/- 0.3 cm2. The average left ventricular end diastolic volume decreased from 186 +/- 59 cm3 before surgery to 129 +/- 37 cm3 at the last control (p < 0.001). The authors conclude that the Physio ring enables reliable and effective mitral valvuloplasty with excellent short term results. The benefits of the flexibility of the Physio ring remain to be evaluated by a randomised trial.