Figure 1: A preoperative transthoracic echocardiographic image showing an interventricular septum thickness of 2.1 cm.

Transesophageal echocardiography probe was placed. Sternotomy was followed by bicaval cannulation. Cardiopulmonary bypass (CPB) was initiated. After cross-clamping, an oblique aortotomy was made towards the non-coronary sinus. The first incision was made to the subannular region at the level of the right and the left leaflet commissures. The second incision was made to the subannular region at the level of the right coronary ostium. These two incisions were adjoined with the third incision which was made 5 mm below the annulus. The myectomy was performed with a thickness of 1 cm and a length of 3-4 cm towards the apex. The myectomy was decided to be sufficient, when the trunk and the base of the papillary muscles became visible. As the mitral valve leaflets were severely thickened and fibrosed with a narrow valve orifice, the mitral valve replacement was performed. Transesophageal echocardiography revealed the pressure gradient of the LVOT as 15 mmHg and no systolic anterior motion (SAM) of the mitral valve was detected. The postoperative course was uneventful. He was followed in the intensive care unit (ICU) for two days and discharged in the eight postoperative day.

The unusual presentation of our case is what makes this case interesting. Hypertrophic obstructive cardiomyopathy is mostly associated with mitral insufficiency rather than MS.[3] The preoperative TTE did not reveal an abnormal anterior motion of the anterior leaflet nor did we observe any regurgitation intraoperatively. There was a severe pressure gradient caused by the MS. The MS may have decreased the already low left ventricular filling even further. The clinical deterioration and pulmonary edema seen in our case, despite medical treatment, was due to the sum of the pathophysiological effects of HOCM and MS; HOCM increased the left ventricular end-diastolic pressure with outflow obstruction resulting in back pressure on the lungs, while MS caused dyspnea due to the restricted left ventricular inflow, thereby, resulting in left atrial pressure and back pressure on the pulmonary circulation.

Pharmacological therapy with beta-blockers, calcium channel blockers, and disopyramide is often beneficial for patients with mild symptoms.[4] However, for patients refractory to the pharmacological therapy, more invasive therapeutic procedures can be lifesaving.

In addition, alcohol-induced septal ablation (ASA) is an interventional treatment modality which aims to decrease the septal muscle mass.[5] Long-term follow-up results are comparable with surgical myectomy.[5] Alcohol-induced septal ablation can also achieve significant reduction of the LVOT obstruction gradient and symptomatic relief.[5] However, complications such as complete heart block are more common after ASA than surgical myectomy.[5] In daily practice, it is mostly performed in older patients with high surgical risk and in those without any intracardiac disease and not requiring open surgery.[5]

Furthermore, surgery yields the best long-term results with good mortality and morbidity rates.[6] Septal myectomy is the conventional procedure in most of the cases.[7] Almost always, sufficient myectomy is achieved, if the papillary muscles are easily visible. Nevertheless, in some patients, myectomy may be insufficient in creating a wide outflow tract. In such cases, mitral valve replacement is the treatment of choice to relieve the LVOT obstruction.[7] In this case, mitral valve replacement was performed, as the mitral valve was not appropriate for repair. We believe that replacement of the valve also contributed to the abolition of the LVOT gradient.[8]

In conclusion, in most cases, hypertrophic obstructive cardiomyopathy does not consist of a single anatomical pathology and it can manifest itself with an unusual clinical presentation, as in our case. Therefore, the approach to each case should be individualized and treatment decisions should be made by expert surgeons. Surgery is a more favorable approach for hypertrophic obstructive cardiomyopathy and can be life-saving in acute deterioration in patients with coexisting hypertrophic obstructive cardiomyopathy and mitral valve pathology.

Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding
The authors received no financial support for the research and/or authorship of this article.

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