(RxWiki News) For a person having a heart attack, the amount of time between first arriving at the hospital and receiving treatment is very important.
Health providers across the US have greatly improved treatment times for patients who have had a heart attack. These days, patients are typically treated within 69 minutes or less of arriving at the hospital.
However, a recent study showed that, despite faster in-hospital treatment, the number of people dying from the most serious type of heart attack has not significantly changed.
Why are more lives not being saved? The authors explained that one possible reason is that patients may delay seeking medical assistance after symptoms first begin.
The length of time that heart tissue is without blood during a heart attack determines the degree of permanent damage. It is crucial not to wait to seek medical attention when heart attack symptoms start.
"Learn the warning signs of a heart attack."
This study examined whether improved hospital treatment times for patients having a heart attack reduced mortality (death) was conducted by Daniel Menees, MD, and Hitinder Gurm, MB, from the University of Michigan and the Veterans Affairs Ann Arbor Healthcare System, and other collaborators.
A heart attack, or myocardial infarction, takes place when a heart artery is obstructed and the blood supply to the heart muscle stops. Immediate medical care is required to open the blockage and restore blood flow.
This study focused only on patients who had the most serious type of heart attack called ST-segment elevation myocardial infarction (STEMI). STEMI is diagnosed using an electrocardiogram — a test that records the electric waves from the heart.
The treatment for STEMI patients to restore blood flow is called percutaneous coronary intervention (PCI). During PCI, a catheter with a deflated balloon is introduced from the groin of the patient and guided to the blockage site, where the balloon is inflated to open the blockage.
The interval of time from the patient’s first contact with medical services to the moment when the balloon is inflated is defined as door-to-balloon time.
The researchers analyzed data from 93,738 admissions across 515 hospitals with PCI capabilities. These admissions were for STEMI patients who underwent PCI between July 2005 and June 2009.
The researchers wanted to investigate if the number of deaths that occurred within one month following PCI were reduced with shorter door-to-balloon times.
The researchers reported that door-to-balloon times progressively decreased by about 9 percent each year. The door-to-balloon time was 83 minutes between 2005 and 2006; 76 minutes between 2006 and 2007; 70 minutes between 2007 and 2008; and 67 minutes between 2008 and 2009. However, the number of deaths remained around 4.7 percent during those four years.
During a heart attack, some conditions increase the risk of death. The researchers separately analyzed data from patients who were older than 75 years old, who had previous heart attacks and who exhibited cardiogenic shock (the heart stopped pumping). These were considered high-risk groups.
Results showed that treatment time also was improved but not mortality. Patients who exhibited cardiogenic shock had the greatest mortality rate (27.3 percent), followed by patients older than 75 years (11.5 percent) and those who had previously had heart attacks (6.7 percent).
Current guidelines recommend a door-to-balloon time of 90 minutes or less. This study reported that only 60 percent of patients admitted to the hospital between 2005 and 2006 met this guideline while the number increased to 83.1 percent between 2008 and 2009.
The researchers explained that a possible reason that the death rate did not decrease was patients took different amounts of time to get medical assistance. Some people take longer to seek care than others after symptoms start. It is estimated that patients usually have symptoms for two hours before they ask for help.
This study had some limitations. For one, its design was not able to detect small changes in mortality even if they existed. It is also possible that further decreasing the time from the recommended 90 minutes did not provide more advantages.
The study concluded that, in addition to aiming for a short door-to-balloon time, other factors may need to be considered to decrease deaths. These factors include the following:
- Educate patients about heart attack symptoms.
- Reduce the interval of time from the time of symptom onset to treatment.
- Reduce the transfer time between medical facilities; be aware of hospitals that don’t have PCI capabilities.
- Improve care after the patient is discharged from the hospital.
In an interview with dailyRx News, Michael Grad, MD, a cardiologist at Cardiovascular Specialists of Texas, estimated that at the hospital where he performs cardiac interventions including PCI, the present door-to-balloon time is between 30 and 45 minutes.
dailyRx News asked Dr. Grad's advice on heart attack warning signs and when to seek medical assistance, and he said, “Any man or woman that has discomfort in the chest, jaw, upper back or left shoulder and who has any of the heart attack risk factors, such as high blood pressure, high cholesterol, use of tobacco, obesity or diabetes, should seek medical attention right away.”
He also added, “The pain may appear only with exertion but can also occur at rest. The pain may be related to other problems such as gastrointestinal or muscular, but it doesn't matter, the person needs to be checked and be sure discomfort is not related with the heart.”
While in-hospital care has been greatly improved, it is now necessary to shift attention and awareness to pre-hospital delays and post-hospital care, and doing so involves participation from patients and their families.
This study was published on September 5 in The New England Journal of Medicine. The authors had no disclosures to make.