When your heart fails
What happens when your heart fails? Heart failure refers to the weakening of the heart muscles so that the heart is unable to adequately perform its function of pumping blood into circulation, which the other organs of the body need.
Shortness of breath is the most common symptom of heart failure. “Other symptoms include swelling or edema in the lower extremities, lack of energy or fatigue, reduced ability to exercise, and lack of appetite and nausea,” cardiologist and internist Dr. Maria Rosario Sevilla, explains. A number of risk factors such as smoking, hypertension, and diabetes can lead to complications such as heart failure, unless arrested at an early stage.
“A lot of diagnosis, however, can be missed if we go by symptoms alone,” observes Dr. Dante Morales, cardiologist at the Manila Doctors Hospital. A number of risk factors are asymptomatic and rarely immediately life-threatening. Thus, the need to screen through ECG, chest X-rays, echocardiography, clinical exams, and laboratory tests. Our blood can offer many clues about our heart’s health.
Cardiovascular disease is still the number one cause of death worldwide. In the Philippines, cardiovascular disease accounts for almost one third (31.8%) of all deaths, making it the leading cause of deaths in the country. There are no available statistics on heart failure, but its prevalence is projected to be high as well, with an estimated 1.8 million of the population suffering from it.
“Heart failure is considered a major clinical and public health challenge, wrongly diagnosed in many instances,” notes Dr. Alan Maisal, professor of medicine at the University of California and director of the Coronary Care Unit and Heart Failure Program of the San Diego Veterans Hospital in California. “In the US, heart failure is a leading cause of hospitalization, with a poor outcome after hospitalization. Studies show a 90-day risk of death of 15 percent and a 30 percent likelihood of being readmitted to the hospital.”
Early identification of patients at risk for heart failure is critical in order to significantly reduce the chances of re-hospitalization and death.
Deaths due to heart failure exceed the death rate for HIV, lung, breast, prostate, and pancreatic cancers combined. “And yet, there is more screening for targeting cancer than heart failure,” says Dr. Maisal.
A breakthrough in the diagnosis of heart failure is the discovery of heart biomarkers such as ST2, a novel indicator of heart stress due to worsening heart failure. Mounting scientific evidence has shown that ST2, a form of body protein, has the predictive ability to identify patients who are at high risk to die due to heart failure.
In the ST2 blood test, the important number to remember is 35. Patients with ST2 levels above the cut-off value of 35 ng/mL have a much higher risk of death, while those with ST2 levels below the clinical threshold are at lower risk, Dr. Maisal explains. ST2 test results are not unfavorably influenced by the age of the patient, impaired kidney function or increased body mass index in the case of overweight or obese individuals, which are limiting factors for other diagnostic biomarker tests for heart failure. “However, any biomarker is not a stand-alone test,” Dr. Maisal remarks. The ST2 test is complementary to the BNP (brain natriuretic pepetide) test, a standard test to determine the severity of heart failure. ST2 testing serves as a useful guide for physicians in treating heart failure patients and helps improve patient care with more personalized treatment, Dr. Maisal adds. “With an earlier and more accurate assessment, heart failure patients can be more aggressively treated with medicines that can effectively improve the heart function and prevent complications, including-worsening of heart failure and death. Subsequent rehospitalization could also be reduced witha more accurate guide at monitoring the effectiveness of treatment.” Repeated measurements or serial determination of the patient’s ST2 level may be more useful to arrive at a more definitive assessment.
The test, which is available as Presage ST2 Assay, has been approved by the US FDA and carries a CE (Conformite Europeenne) mark from the European regulatory authorities.
In the Philippines, it is exclusively distributed and marketed by United Laboratories, Inc.