SURGICAL SEPTAL MYECTOMY BY TRANSAPICAL APPROACH FOR RELIEF OF LEFT VENTRICULAR OUTFLOW TRACT IN HYPERTROPHIC CARDIOMYOPATHY.

Simic D., Serrano C., Gonzalez AI., García Fernández J.



BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a heart muscle disease characterized by left ventricular hypertrophy. A left ventricular outflow tract (LVOT) gradient is present in most patients with HCM. This is the most important determinant of limiting symptoms in patients with HCM. Both pharmacologic and nonpharmacologic therapy options exist.


CASE REPORT

We report a case of septal myectomy by transapical approach under balanced anesthesia and on cardiopulmonary bypass (CPB). It was a 34 years old female with HMC (NYHA class III). Preoperative coronariography with no remarks and transthoracic ecocardiography (TTE) with anteroseptal and apical HCM (22mm). LVEF was normal. Monitoring at the OR included ASA standards plus femoral artery canalization, cerebral oximetry, Swan-Ganz catheter and TTE. An apical ventriculotomy was made lateral to the left anterior descending artery. Approximately 10g of ventricular septal muscle was removed. After CPB a severe mitral insufficiency was observed, thus mitral valve repair (annuloplasthy) was performed. Pacemaker in AAI mode. Patient leaves to ICU with Noradrenaline and Dobutamine at low doses.

In the first hours inotropic drugs were withdrawn. Troponins climbed to a peak and extubation was made in the first day after surgery (DAS). In the following days the patient developed a complete heart block and depended on the pacemaker for 4 days. TTE after surgery: mild MI after mitral repair, HCM improved (16mm). Patient was discharged from ICU on the 4th DAS.


DISCUSSION

Septal myectomy relieves LVOT obstruction by direct removal of septal muscle. In addition, abnormalities of the mitral valve can be addressed at the time of surgery. The transapical approach is a difficult procedure and is only performed at very limited hospitals with experience in this pathology. In Spain this was the first time this procedure has ever been made.
  
LEARNING POINTS

Complications include excessive removal of muscle causing a septal defect, development of branch block or CHB and MI due to papilar muscle section. Myectomy results in resolution of LVOT gradient and improvement of failure symptons in almost all patients, and is associated with excellent long term survival1&2.


REFERENCES

Woo A et al. Clinical and echocardiographic determinats of long term survival after surgical myectomy in HCM. Circulation 2005; 111:2033
Kunkala et al. Transapical approach to myectomy for midventricular obstruction in HCM. Ann Thorac Surg. 2013 Aug;96(2):564-70

surgical septal myectomy by transapical approach for relief of left ventricular outflow tract in hypertrophic cardiomyopathy