▌Dong Jianzeng, Du Xin, Lv Qiang, Beijing Anzhen Hospital Affiliated to Capital Medical University
February 28
International Rare Disease Day
Heart disease, as a common cause that threatens human health, has already attracted more and more people's attention.
However, there is such a group of patients who have a "starch heart".
This is a disease called transthyretin amyloid cardiomyopathy. Because the disease is very rare and easily missed and misdiagnosed, the patient's life is seriously threatened.
Therefore, such diseases often need to receive more attention and are not invisible because of their rarity.
Cardiac amyloidosis, a rare and fatal disease
"Amyloid heart", also known as transthyretin amyloid cardiomyopathy (ATTR-CM), is a type of cardiac amyloidosis and a rare fatal disease. Patients are also called "amyloid people".
The disease is mainly caused by the deposition of abnormally functioning proteins in the interstitium of the heart muscle. These proteins look like amyloid fibrils under the microscope, so they are named amyloidosis, not true amyloid.
It is worth noting that ATTR-CM is most likely to be misdiagnosed as hypertrophic cardiomyopathy clinically because ATTR-CM is mostly manifested as myocardial hypertrophy on echocardiography.
However, unlike hypertrophic cardiomyopathy, myocardial hypertrophy in ATTR-CM patients is only a kind of "puffiness", despite the ventricular wall thickness of 12mm and above, but the ECG does not have high voltage, which is a very important difference from traditional myocardial hypertrophy Characteristics.
Transthyretin amyloid cardiomyopathy is divided into wild-type and genotype.
The prevalence of wild-type tends to increase with age, with most patients aged 60 years and older.
The genotype has familial aggregation and is autosomal dominant inheritance.
After a patient is diagnosed with ATTR-CM, if the cause cannot be treated in time, the survival time is short, and the average survival time is only 2 to 5 years.
Why is ATTR-CM difficult to diagnose?
This is mainly due to the fact that the disease is a multisystem disease with poor specificity of clinical symptoms.
In wild-type patients, lumbar spinal stenosis (eg, low back and leg pain), carpal tunnel syndrome (eg, finger numbness) and nontraumatic rupture of the biceps tendon are the main ones.
In patients with the hereditary type, the main symptoms are dry eyes, redness, pain, hepatomegaly, and gastrointestinal effects (such as diarrhea or constipation, nausea and vomiting), peripheral nerve disease, and skin purpura.
There are also some patients with renal involvement, manifested as proteinuria and renal insufficiency.
Clinically, the cardiac manifestations of ATTR-CM patients are mainly heart failure, including dyspnea, easy fatigue, decreased activity tolerance, lower extremity edema, etc., and arrhythmias, including atrial arrhythmias (such as atrial fibrillation), bundle branch conduction. Patients with complete heart block and complete heart block may have symptoms of "palpitation".
Beware of abnormal body "signals"
Due to the insidious and variable clinical manifestations of ATTR-CM, coupled with the long-term lack of understanding of the disease in China and the limited diagnostic ability, many patients are often misdiagnosed, missed or delayed in treatment.
However, judging from the clinical manifestations of patients, there are still many abnormal "signals" in the body that deserve everyone's vigilance.
Especially for heart failure patients over 60 years of age with preserved ejection fraction, if they are intolerant to standard heart failure drug treatment (hypotension), the QRS voltage and left ventricular wall thickening on ECG are inconsistent, non-high voltage appears, and ultrasound shows left ventricular Increased wall thickness and autonomic dysfunction (including gastrointestinal distress or unexplained weight loss) warrant a high suspicion of myocardial amyloidosis.
Hereditary ATTR-CM is an autosomal dominant disease with a 50% chance of inheritance, that is, if one parent is a carrier, the child has a 50% chance of inheritance.
Therefore, if there is a family history, it is recommended that immediate family members choose to screen for the TTR gene to determine whether they carry a mutated TTR gene, so as to facilitate follow-up management, early prevention and intervention.
Wild-type ATTR-CM is not hereditary and occurs more in elderly patients. It is particularly important to correctly identify whether the symptoms of heart failure in elderly patients are ATTR-CM.
ATTR-CM is relatively rare, and the diagnostic requirements are high, so it is best to go to a center experienced in the diagnosis and treatment of cardiac amyloidosis when this type of disease is suspected.
At present, the complete diagnosis chain of ATTR-CM needs to firstly perform blood and urine immunofixation electrophoresis and serum free light chain determination, color Doppler ultrasonography, and electrocardiogram to indicate whether there is the possibility of amyloidosis. PYP radionuclide imaging can be used to further diagnose whether For ATTR-CM.
In addition, genetic sequencing is recommended for all confirmed ATTR-CM patients.
Early screening, early diagnosis and early treatment are the key
For a long time, the treatment of "starch people" after diagnosis is mainly symptomatic treatment to relieve related symptoms, and some patients even need combined liver and heart transplantation for treatment.
Fortunately, in 2020, the anti-cause treatment drugs for relieving ATTR-CM have been launched in China, enabling domestic patients to obtain better disease remission and improved quality of life.
In April 2021, "Chinese Expert Consensus on Diagnosis and Treatment of Transthyretin Cardiac Amyloidosis" was officially published in "Chinese Journal of Cardiovascular Diseases", which is also the first standardized diagnosis and treatment process for ATTR-CM in China.
In December 2021, the National Medical Insurance Catalogue was updated, including ATTR-CM's inclusion of 7 innovative rare disease drugs, including ATTR-CM drugs, into the National Medical Insurance Catalogue, which greatly reduced the economic burden of patients' medication and brought diagnosis and treatment to ATTR-CM patients. new Hope.
At the same time, effective and accessible treatment methods will be widely covered with the implementation of medical insurance, which will promote the enthusiasm of clinicians for diagnosis and treatment, and then promote the comprehensive development of the field of ATTR-CM diagnosis and treatment in my country, helping more patients to benefit.
However, the damage of ATTR-CM to the heart is not easy to reverse. Even with drug treatment, it is difficult to eliminate the originally deposited amyloid changes in the body. Therefore, early screening, early diagnosis, and early treatment are particularly critical.
Improving the awareness of ATTR-CM among patients and the majority of medical staff is also very important to improve the diagnosis and treatment rate of the disease.
Patients with this disease are often scattered in cardiology, neurology, ophthalmology and other departments. At present, many doctors, even cardiovascular doctors, still do not know enough about this disease. It is necessary to pass training, diagnosis guidance and popularization of treatment standards, so as to improve the general medical staff's understanding of ATTR - Awareness of CM disease.
Accurate diagnosis is the key to precise treatment. However, clinical diagnosis and treatment also face many challenges. There are not many hospitals with diagnosis and treatment capabilities in China, which are far from meeting the needs of patients. Therefore, it is necessary to accelerate the establishment of a complete and systematic disease diagnosis and treatment system.
In addition, most of the clinical symptoms of rare diseases are not a single manifestation, and promoting multidisciplinary diagnosis and treatment in hospitals is also of great significance for early diagnosis and symptomatic treatment of diseases.
In fact, rare diseases have always been a challenge for all mankind, and it is necessary to step into the public's vision of care, so that the rare disease group can receive more care and support.