ABOUT HOCM
TAILORING SURGERY. About the septal myectomy, the most advanced technique of treatment in the hypertrophic obstructive cardiomyopathy.
About hypertrophic obstructive cardiomyopathy
The hypertrophic obstructive cardiomyopathy (HCM) is a primary cardiac disease, most often determined by genetic factors. It is characterised by the thickening of the ventricular walls and the disorganisation of the architecture of the cardiac muscle. It is the most frequent form of cardiomyopathy, its prevalence being of 0.2% on the general population.
Among the patients with HCM, an important ratio of them, of about 30%, develop the obstructive form, called hypertrophic obstructive cardiomyopathy (HOCM). It is caused by the fact that in repose or during a physical challenges (Valsalva procedure), inside the left ventricular ejection tract appears a pressure gradient. If it is higher than 50 mmHg, the obstruction is considered hemodynamic important.
Often, the ventricular hypertrophy is associated with some abnormalities of the mitral apparatus, presenting mitral insufficiency, very frequently a severe one, which can lead to the dynamic obstruction of the ventricle. Sometimes this is de main principle of the obstruction mechanism of the ejection tract – the case of patients with relatively thin septum.
Causes of hypertrophic obstructive cardiomyopathy:
The causes of hypertrophic obstructive cardiomyopathy are not yet completely elucidated. There are data that suggest that is a hereditary disease with an autosomal dominant pattern. A heterogenicity may explain the variations of the phenotype, the clinical manifestations and even the prognostic, about 30% of the cases being caused by the mutations of the gene that code the hard chain of the beta cardiac myosin, localised on 14th chromosome. Recently were described genetic mechanism of 15th chromosome, of the cardiac T troponin of 1st chromosome, responsible for 15% of the HCM hereditary cases.
Most frequent symptoms:
Clinically speaking, the symptomatology varies widely, from the asymptomatic to disabling cases with severe cardiac insufficiency or sudden death.
The most common symptom that patients accuse is “a fatigue” without any certain cause, accompanied by dizziness, the difficulty of performing ordinary efforts, which previously weren’t a problem (climbing, getting dressed, walking, etc). Being very often confused with other disease manifestations, the cardiologist may suspicion cardiac disease if there appear:
- Dyspnoea, accentuated by tachycardia;
- Angina pectoris, although not always highlighted by extensive changes on the EKG;
- Syncope, which may appear at rest, after intense effort, as a result of a sudden reduction of venous return;
- Arrhythmias and palpitations, etc.
HOCM is one of the main causes of sudden death at young patients, mostly performance athletes.
The diagnosis of hypertrophic obstructive cardiomyopathy
Besides clinical examinations, the evaluation of these patients involve the following investigations: electrocardiogram, transthoracic echocardiography at rest/stress, transoesophageal echocardiography, ECG Holter/48h, cardiac MRI (essential, including in the intraoperative management of patients) and most frequently the genetic testing.
The diagnosis of HOCM patients is quite difficult, because it requires high expertise and a large casuistry in order to make the difference between a physiological thickened heart wall at effort and a pathological thickened heart wall. It is, for example, the case of the performance athletes, a specific category, where the diagnostic process may lead to avoiding of some dangerous manifestations, the disease culminating with sudden death on the sports field. There are studies made in USA according to which 36% of sudden death of the athletes were caused by the HOCM. It is difficult to make the difference between an affected heart by HOCM and the heart of an athlete, physiologically thickened by the prolonged and constant effort, becoming necessary additional tests and the correlation with the result of other investigations in order to exclude the pathology.
The treatment of hypertrophic obstructive cardiomyopathy
The treatment is addressed to symptomatic patients. It can be medicamentary, effective in many cases; but in cases of resistant to the drug treatment, it is prescribed the invasive treatment. According to both European and American medical guidelines, the recommended invasive therapy is the surgical approach. According to the same guidelines, because of the superior results, it must be performed only in experienced centres. The surgical treatment represents at this moment a I class indication and classically consists in the extended septal myectomy or the Morrow procedure. The myectomy involves the extended muscular resection of the septum in order to sufficiently enlarge the ejection tract of the left ventricle and thus to reduce the SAM movement (systolic anterior motion) of the mitral valve.
Our team is performing the Ferrazzi’s technique consisting in the „one piece” myectomy technique, that involves the resection of the sept in one piece, whose dimensions are strictly calculated and designed individually, for each patient; we are also performing in each patient a mitral valve apparatus reconstruction mainly by cutting the secondary chordae of the mitral valve and mobilization of the papillary muscles. Technically difficult, it can be performed only after a long experience and it is based on the data obtained from the echocardiography and the cardiac MRI. ”
About the Ferrazzi’s technique, one of the most advanced technique in surgical treatment of HOCM
More than other pathologies, on the surgical treatment of HOCM, the pre-operation strategy is personalized and very often more laborious than the intervention itself. In the pre-operation moment, it is elaborated a strategic plan of the surgery, and are calculated the dimensions of this unique piece (length, width, thickness), dimensions meant to perfectly match with the scripted data obtained from the echocardiography and from the cardiac MRI.
Dr. Lucian Dorobantu: “We are talking about a niche surgery, personalized, a reconstructive surgery, par excellence, of the left ventricle architecture”. We are rebuilding the whole ejection tract of the heart muscle, the tunnel through which exits the blood that narrows. In step I: we aim to enlarge this tract, “digging a new one”, through which the blood can flow, without any obstruction. The way out from the left ventricle is rebuilt pushing out of this “tunnel” the mitral valve, and reconfiguring its way, in order to give back its functionality. Step II: we are looking to remodelling the mitral valve, which during the process becomes insufficient. The papillary muscles are brought too in the centre of the left ventricle. The fact that in over 98% of the cases we manage to preserve the mitral valve is extremely important for the patient and for the quality of his life, on long term.”
The benefits of this unique technique
There is an important part of the patients with significant intraventricular gradient who have a moderate septal hypertrophy, that most of the times associates abnormalities of the mitral apparatus, thing that contributes to the obstruction of the ejection tract.
The team coordinated by Prof. Paolo Ferrazzi, surgeon who by far has the greatest European experience on the HOCM treatment, has established the importance of the secondary mitral chords on the mitral insufficiency caused by HOCM. The resection of the secondary mitral chords associated with the myectomy, together with the papillary muscles’ mobilization, reduces the VMA tethering and pushes the coaptation point posteriorly, removing the VMA from the ejection tract.
This technique, published in 2015 in the „Journal of the American College of Cardiology”, the world’s most prestigious profile magazine, comes to underline again the fact that according to the latest European and American guidelines for HOCM, the management of this disease must be done only by specialized medical teams.
The complex investigation protocol, by dedicated cardiologists, with the support of specialized cardiac MRI radiologists, coordinated by specialized surgeons are the defining elements to perform an adequate and modern treatment.
The benefits for the patients that revolve to these techniques are: the disappearance of the symptoms and the important reduction of risk of sudden death, post operatory mortality risk similar to general population and stable results on long term, the patient returning to his normal life.
When the intervention is impossible to perform, in case of the patients with important comorbidities, with high operatory risks, it is recommended the alcoholic septal ablation. It was proven that this technique needs a favourable anatomy and doesn’t resolve the mitral insufficiency, causing more frequent complications in terms of residual gradient in the left ventricle ejection tract, with an incidence of the branch block or the complete atrioventricular block. This is why, in our opinion, this approach is reserved exclusively to the inoperable cases.
The role of the interdisciplinary team integration in the treatment of HOCM
Our goal is to think together, as a complex team, an optimal therapeutic process on the benefit of each patient. Because we are talking about a complex pathology, in the treatment of HOCM each member of the interdisciplinary team has a key-role. We are using a “one piece” technique, a “step-by-step” procedure.
It is very important that each member understands the disease and its mechanisms: the cardiologist has to make a perfect case evaluation, close to the radiologist, specialized in the imaging of the disease. It is important that the surgical team is highly specialized in this niche surgery, team that must include a very specialized intensive care specialist, in order to ensure the management of every stage, pre, during and post-operatory adapted to the specific mechanisms of this pathology, very different by other heart diseases.
The quality of the patient’s life after the heart surgery is a life that remodels, through simple gestures: the respiration, getting dressed, climbing stairs and any gesture that before the intervention involved a significant effort, all these return in a similar prognostic of a person who hasn’t ever suffered of disease. This is the final goal that we aim with any surgery we perform: the life and the quality of life of every patient.
HOCM Research and education
The Coordinator of the European Cardiomyopathy Center, Dr. Lucian Dorobantu is a co-author of the study published in 2020 in one of the most prestigious Cardiology magazines – Journal of The American College of Cardiology. The research brings notions and information about the causes and the treatment of the obstruction of HCM, that had never been published or discussed in the medical world. Cardiomyopathy Center is part of the group that changes the history and the definition of a disease – Cardiovascular surgeon Dr. Lucian Dorobantu.
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