Noonan syndrome associated with anomalous coronary artery and other cardiac defects

This case-report describes an 11-month-old infant, who had been diagnosed with Noonan syndrome with a variety of associated anomalies. Multiple cardiac anomalies were present, consisting of dysplastic pulmonary valve, symmetric biventricular hypertrophy, atrial septal defect and right ventricular outflow tract (RVOT) obstruction, in which the pressure gradient measured 73 mmHg, and anomalous coronary artery. Systolic anterior motion of the mitral valve (SAM) was present, without remarkable clinical significance. RVOT transannular repair with non-cusped xenograft along with resection of hypertrophied right ventricular outflow myocardium. Left ventricular outflow tract (LVOT), which had no clinical sign of obstruction, was left untouched, expecting the RVOT repair also effectively release LVOT dynamic obstruction. The postoperative echocardiography revealed residual SAM without significant pressure gradient through LVOT.     

Noonan syndrome associated with anomalous coronary artery and other cardiac defects.

This case-report describes an 11-month-old infant, who had been diagnosed with Noonan syndrome with a variety of associated anomalies. Multiple cardiac anomalies were present, consisting of dysplastic pulmonary valve, symmetric biventricular hypertrophy, atrial septal defect and right ventricular outflow tract (RVOT) obstruction, in which the pressure gradient measured 73 mmHg, and anomalous coronary artery. Systolic anterior motion of the mitral valve (SAM) was present, without remarkable clinical significance. RVOT transannular repair with non-cusped xenograft along with resection of hypertrophied right ventricular outflow myocardium. Left ventricular outflow tract (LVOT), which had no clinical sign of obstruction, was left untouched, expecting the RVOT repair also effectively release LVOT dynamic obstruction. The postoperative echocardiography revealed residual SAM without significant pressure gradient through LVOT.     

Obstruction dynamique intraventriculaire gauche après chirurgie réparatrice valvulaire mitrale

A 71 -years-old patient, undergoing mitral valve repair for degenerative valvulopathy and correction of pectus excavatus experienced a cardiogenic shock after weaning from cardiopulmonary bypass. The shock occurred after calcium chloride administration and was unresponsive to inotropic drugs. Transoesophageal echocardiography showed left ventricular outflow tract obstruction due to systolic anterior motion (SAM) of the mitral valve. Discontinuation of inotropic drugs and volume expansion restored the haemodynamic status. By its haemodynamic effects calcium chloride can cause left ventricular outflow tract obstruction, recognized by transoesophageal echocardiography.     

Echocardiography in combined discrete and hypertrophic subaortic stenosis.

A 10-year-old boy with discrete subaortic stenosis had coexisting abnormal systolic anterior motion of the mitral valve, demonstrated by echocardiography, a sign normally taken as indicating the presence of idiopathic hypertrophic subaortic stenosis. Surgical removal of a fibromuscular diaphragm abolished the echocardiographic signs of discrete subaortic stenosis but abnormal systolic anterior motion of the mitral valve persisted. A severe low cardiac output state complicated immediate recovery after removal of the left ventricle outflow obstruction, and was overcome only with considerable difficulty. The presence of hypertrophied septal muscle, and the associated small left ventricular cavity size, was thought to be the immediate cause of these problems, so that recognition of marked septal hypertrophy, together with abnormal anterior systolic movement of the mitral valve, should serve as a warning that similar difficulties are likely to bae encountered by other patients, after removal of the obstruction in subaortic stenosis. In our experience other forms of left ventricle outflow tract obstruction have not been found to show such a marked degree of asymmetric septal hypertrophy, but this does not mean it may not occur.     

Left Ventricular Outflow Tract Obstruction After Mitral Valve Replacement

We describe a patient with left ventricular outflow tract obstruction after mitral valve replacement preserving the anterior subvalvular apparatus. Postoperative transesophageal echocardiography demonstrated systolic narrowing of the left ventricular outflow tract by a bulging septum and systolic anterior motion of the preserved anterior mitral leaflet. Septal myectomy and transaortic mitral apparatus resection enabled us to relieve the left ventricular outflow tract obstruction. This suggests that septal hypertrophy might be a relative contraindication to the preservation of the anterior mitral subvalvular apparatus in mitral replacement.     

Myectomy as an alternative solution for systolic anterior motion in a patient who underwent mitral valve repair

Systolic anterior motion (SAM) of the mitral apparatus is a relatively frequent complication of mitral valve repair. When significant SAM persists despite intraoperative medical therapies, a second repair is generally required. We describe a rare case of SAM due to a hypertrophic septum in a patient who underwent mitral valve repair, with no preoperative obstruction of the left ventricular outflow tract. The present case of SAM was successfully treated only with transaortic septal myectomy. Therefore, myectomy might be considered as an alternative solution for SAM that is suspected to be caused by a hypertrophic septum after mitral valve repair.     

Systolic anterior motion of the mitral valve despite the sliding leaflet technique for repair of the mitral valve

We report a systolic anterior motion of the anterior mitral leaflet despite employing the sliding leaflet technique for repair of mitral valve regurgitation. A 65-year-old man with chronic, symptomatic mitral regurgitation due to ruptured chordae tendineae underwent mitral valve repair by quadrangular resection of the posterior leaflet and sliding leaflet technique with ring annuloplasty. After weaning from cardiopulmonary bypass, left ventricular outflow obstruction developed and transesophageal echocardiography demonstrated systolic anterior motion of the mitral valve and severe mitral regurgitation. Non-operative treatment resolved the outflow tract obstruction, systolic anterior motion and mitral regurgitation. We conclude that post-repair systolic anterior motion can still occur after the sliding plasty procedure and that medical treatment can successfully resolve systolic anterior motion and outflow tract obstruction in most patients.     

Management of intraoperative systolic anterior motion of the mitral valve after valve plasty: a case report

We report a case of intraoperative systolic anterior motion (SAM) of the mitral valve after mitral valve plasty (MVP). A 53-year-old man underwent MVP for mitral regurgitation (MR). MVP was carried out uneventfully. We weaned the patient from cardiopulmonary bypass (CPB) with continuous administration of catecholamines and a vasodilator. However, after the weaning from CPB, transesophageal echocardiography (TEE) detected moderate MR with left ventricular outflow tract obstruction (LVOTO) due to SAM. LVOTO and SAM gradually disappeared after the reduction of catecholamines and volume loading. He was transferred to the intensive care unit postoperatively and extubated 18 hours after operation. Transthoracic echocardiography after operation revealed disappearance of MR. He was discharged from the hospital on postoperative day 15 without complications. We successfully managed MR with LVOTO due to SAM by reduction of catecholamines and volume loading.     

Use of the Alfieri edge-to-edge technique to eliminate left ventricular outflow tract obstruction caused by mitral systolic anterior motion

A 68-year-old woman with concentric left ventricular hypertrophy, prosthetic valve endocarditis with aortic root abscess, and sepsis had aortic root replacement with an aortic allograft. On weaning from cardiopulmonary bypass, she had hemodynamic instability caused by systolic anterior motion of the mitral valve, which resulted in a left ventricular outflow tract obstruction; the peak pressure gradient across the left ventricular outflow tract was 130 mm Hg, and there was moderately severe (3+) mitral regurgitation. After reinstitution of cardiopulmonary bypass, a central Alfieri edge-to-edge stitch was placed between the anterior and posterior leaflets of the mitral valve. This reduced the gradient across the left ventricular outflow tract to 10 mm Hg and eliminated the mitral regurgitation, which enabled successful separation from cardiopulmonary bypass.     

Case in which landiolol hydrochloride improved left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve following mitral valve plasty

We report a case of left ventricular outflow tract (LVOT) obstruction caused by systolic anterior motion of the mitral valve (SAM) following mitral valve plasity (MVP). A 65-year-old man underwent mitral valve plasty for grade III mitral valve regurgitation. The plasty was done smoothly and the patient was weaned from cardiopulmonary bypass successfully with continuous dobutamine infusion. However, about 30 minutes after the weaning, severe cardiovascular collapse developed. Inotropic agent, such as dobutamine, ephedrine, or calcium hydrochloride was not effective. Trans-esophageal echocardiography (TEE) showed severe mitral valve regurgitation with LVOT obstruction due to SAM. The collapse was successfully treated with volume loading and a small amount of a beta1-adrenergic antagonist, landiolol hydrochloride. We conclude that acute LVOT obstruction with SAM could develop following MVP. TEE was a much useful tool for early diagnosis and landiolol hydrochloride would be a notable agent for nonsurgical treatment of LVOT obstruction with SAM.     

Robotic trans-mitral septal myectomy and papillary muscle reorientation for HOCM combined with or without mitral valve repair: Technical aspects – How we do it

Hypertrophic obstructive cardiomyopathy (HOCM) is one of the more common genetic disorders. The pathophysiology and natural history of the disease have been well studied. Left ventricular outflow tract obstruction (LVOTO) and systolic anterior motion (SAM) of the anterior mitral leaflet can result in sudden cardiac death, progressive heart failure and arrythmias. Surgical septal myectomy for HOCM is the standard of care and is routinely performed through a median sternotomy. Septal myectomy has also been performed using the trans-atrial, trans-mitral approach either directly or with robotic assistance. In cases with severe LVOT obstruction in the setting of only mild to moderate proximal septal hypertrophy, intrinsic problems with the mitral valve contribute. Typically, these are hypermobile papillary muscles and or excessive height of the anterior mitral leaflet. Combining septal myectomy with reorientation of hypermobile anteriorly positioned papillary muscles has shown to prevent SAM and thereby additionally decrease the subvalvular aortic outflow obstruction. Our extensive experience in both septal myectomy and robotic mitral valve repair has given us a different perspective in approaching the primary mitral regurgitation in HOCM patients where a combined septal myectomy, papillary muscle reorientation and complex mitral valve repair has been safely performed using the less invasive robotic-assisted approach.Our objective here is to discuss the technical aspects of the procedure.     

Myocardial Bridge or Something Else?

In this E-Challenge, the authors report on a patient with symptoms of exertional dyspnea and angina, scheduled to have surgical unroofing of an identified myocardial bridge (MB). An MB is very common in patients with hypertrophic cardiomyopathy (HCM). Intraoperative transesophageal echocardiography with provocative maneuvers revealed the patient had a systolic anterior motion of the mitral valve with septal contact and resulting outflow tract obstruction despite the notable absence of significant basal septal hypertrophy. HCM has many phenotypic variants that can make the identification of patients with latent left ventricular outflow tract obstruction difficult in the absence of a high index of suspicion. In this report, the authors discuss the association between MBs and HCM and the importance of recognizing phenotypic variants of HCM.     

Mitral valve replacement and septal myectomy for hypertrophic obstructive cardiomyopathy

A 76-year-old woman with a diagnosis of hypertrophic obstructive cardiomyopathy was referred to our hospital’s surgical department. Her echocardiogram revealed diffuse left ventricular hypertrophy, moderate mitral valve regurgitation with systolic anterior motion of the mitral valve, and left ventricular obstruction with a peak outflow gradient of 108 mm Hg. We performed a transaortic rectangular septal myectomy with an incision at a width, depth, and length of 1 cm, 1 cm, and 3 cm, respectively. However, the transesophageal echocardiogram revealed residual left ventricular obstruction and systolic anterior motion, and we subsequently replaced the mitral valve with a mechanical valve. The patient’s postoperative course was uneventful, and the peak outflow gradient decreased to 15 mm Hg. Although transaortic septal myectomy is the most common surgery currently used for hypertrophic obstructive cardiomyopathy, mitral valve replacement should remain an option in patients with diffuse left ventricular hypertrophy who fail to improve after myectomy alone.     

Echocardiographic diagnosis of left ventricular outflow tract obstruction after mitral valve replacement with subvalvular preservation.

We describe two cases of left ventricular outflow tract obstruction after mitral valve replacement with complete retention of the subvalvular apparatus. The first patient deteriorated immediately after insertion of a high-profile bioprosthesis. In the second patient, chronic left ventricular outflow tract obstruction developed after the insertion of a low-profile mechanical prosthesis. The clinical course of left ventricular outflow tract obstruction after mitral valve replacement with complete retention of the subvalvular apparatus may differ greatly. Evaluation of the left ventricular outflow tract by perioperative transesophageal echocardiography or epicardial echocardiography is essential in the prevention and treatment of this complication.     

Septal myectomy and myotomy attenuate left ventricular hyper-contractility in a child with hypertrophic obstructive cardiomyopathy

Septal hyper-contractility is thought to be the principal cause of significant left ventricular outflow tract obstruction (LVOT) and systolic anterior motion (SAM) of the mitral valve by making the distance between the mitral valve and papillary muscle shorter. A seven-year-old patient with severe hypertrophic obstructive cardiomyopathy underwent direct interventricular septal myectomy/myotomy using the resection/crush method to modify hyper-contractility. The procedure successfully reduced the pressure gradient from 180 mmHg to 7.6 mmHg, and systolic anterior movement of the mitral leaflet disappeared. Mitral regurgitation improved from grade 2 to grade 0. Postoperative echocardiographic vector velocity imaging (VVI) study revealed a reduced twist angle, depicting attenuated ventricular contraction power from a maximum twist 17.9° to 7.9°. Perioperative VVI revealed that interventricular septal myectomy/myotomy is useful, not only in reducing LVOT obstruction, but also in reducing hyper-contractility, which increases the distance from the mitral valve to the papillary muscle and relieves SAM.     

Post-mitral valve repair systolic anterior motion produced by non-obstructive septal bulge

Objective: Systolic anterior motion (SAM) may rarely occur after mitral valve reconstruction due to different anatomic factors. Several techniques have been described to reduce the incidence of post-repair SAM, e.g. leaflet sliding plasty. However, SAM can still occur after these special procedures. We reviewed data of patients developing SAM with significant mitral regurgitation due to non-obstructive septal bulge. Methods: During a 2-year period mitral valve repair was performed in 358 patients. Five of 358 (1.4%) patients with a mean age of 52±10.5 years developed post-repair SAM with severe mitral insufficiency due to non-obstructive septal bulge. Data of these patients were analyzed retrospectively and controlled after a mean follow-up of 18±2.7 months. Results: Preoperative echocardiography showed end-diastolic septum diameter of 7, 10, 10, 11 and 15 mm. The ratio between end-diastolic septum diameter and free wall diameter was 1 in four patients and 1.25 in one patient. There was no left ventricular outflow tract obstruction (LVOT). Intraoperative data revealed large myxomatous anterior (four patients) and posterior (three patients) leaflets. Quadrangular resection of posterior leaflet was carried out in four patients and sliding plasty in one patient. Cause for post-repair mitral regurgitation was a non-obstructive septal bulge. During a second pump run septal bulge was resected. Mean aortic cross-clamp time and cardiopulmonary bypass time for this procedure was 15±1.4 and 28±3.1 min, respectively. Mitral regurgitation disappeared in all patients immediately after this procedure. The grade of mitral regurgitation at follow-up was 0–1 in all patients. One patient had subaortic gradient of 36 mmHg. Conclusions: If mitral regurgitation occurs after primary successful mitral repair, septum bulge should always be considered as the primary cause for SAM even there is no preoperative gradient in LVOT. Before performing time-consuming corrective operations to relieve SAM, a septum resection should be carried out during a short second pump run.     

Obstruction of left ventricular outflow tract after mechanical mitral valve replacement

We successfully operated on a patient with a rare complication of left ventricular outflow tract obstruction after mitral valve replacement. In a 57-year-old woman with previous mitral valve replacement, transthoracic echocardiography showed left ventricular outflow tract obstruction as a result of anterior displacement of the mitral prosthesis and local thickening of the interventricular septum. Cardiac surgery verified this rare lesion. During the operation, the anterior half of the prosthesis ring was cut away from hyperplastic tissue and sutured to the natural mitral annulus. Subaortic hyperplastic tissue was excised to enlarge the left ventricular outflow tract. The patient had an uneventful postoperative recovery, and left ventricular outflow tract obstruction disappeared on postoperative transthoracic echocardiography.     

Subaortic obstruction: intraoperative echocardiography as an adjunct to operation

Fourteen patients undergoing operation for subaortic obstruction (membranous obstruction in 11 patients, tunnel obstruction in 2 patients, obstruction due to reduplicated mitral valve tissue in 1 patient) were evaluated by intraoperative epicardial echocardiography. In all 9 patients with "discrete" obstruction who underwent prebypass epicardial echocardiography, the septal and lateral attachments of the lesion were correctly demonstrated. The precise extent of tunnel stenosis was seen in both patients. The lateral attachment of the membrane in 4 patients and multiple extensions in another 2 were identified by the epicardial study (having been missed on precordial echocardiography). The discrete membrane was enucleated in 10 of the 11 patients and was partially resected in 1. One tunnel obstruction was completely relieved; the other was partially relieved. Reduplicated mitral valve tissue in the remaining patient was completely resected. Epicardial imaging after bypass showed remnants of the membrane in 2 patients. Intraoperative Doppler echocardiography and color flow imaging confirmed the absence of clinically significant residual gradients (less than 20 mm Hg) in all but 1 patient with tunnel obstruction. Epicardial imaging provided excellent morphological information about obstructive lesions of the left ventricular outflow tract and enabled immediate assessment of surgical repair.     

Another pitfall in minimally invasive mitral valve repair

We report a case of severe systolic anterior motion (SAM) and dynamic left ventricular outflow obstruction after repair of a flail posterior leaflet of the mitral valve. The reason for SAM was found to be due to traction on the pericardial stay sutures placed to expose the surgical field. The SAM and the outflow obstruction were completely resolved by cutting these sutures. Our case demonstrates the contribution of geometric factors in the development of SAM and left ventricular outflow obstruction and emphasizes the need to evaluate the heart in its natural position within the mediastinum.     

Nonobstructing Accessory Mitral Valve Tissue and Ventricular Septal Defect

A 4-month-old boy with ventricular septal defect was found to have accessory mitral valve tissue attached to the anterior leaflet of the mitral valve. Operation was successfully performed to excise the accessory mitral tissue in the left ventricular outflow tract and close the ventricular septal defect. Most previously reported cases with accessory mitral valve tissue were associated with left ventricular outflow tract obstruction. This boy had no pressure gradient across the left ventricular outflow tract. The indications for prophylactic excision of nonobstructing accessory mitral valve tissue in a patient with other forms of congenital cardiac disease are discussed.