In a new study, researchers found that the longer the time between when heart attack symptoms start and a patient has an artery-clearing percutaneous coronary intervention (PCI), the more damage to the heart muscle.
The research was conducted by a team at Mount Sinai Heart Health System.
A heart attack happens about every 40 seconds in the U.S., and the most common heart attack is caused by a complete blockage in a coronary artery, called ST-elevation myocardial infarction (STEMI).
STEMI patients are most often treated with PCI, also known as angioplasty with stent, in which a catheter with a deflated balloon is inserted into the narrowed heart artery.
Subsequently, the balloon is inflated, which clears the obstruction and restores blood flow. A stent is then inserted to keep the artery open.
The time to opening the blocked coronary artery with PCI in heart attack patients is an important indicator of how a patient does after their heart attack.
There are two measures for this time.
One is symptom-to-balloon time, which is before the patient arrives to the hospital after symptoms start, to when that patient has a PCI; second is door-to-balloon time, the time from hospital arrival to PCI.
In the study, the team analyzed the data from 10 studies that followed more than 3,100 STEMI patients enrolled after PCI between 2002-2011.
Patients’ hearts were assessed within between 3-12 days after PCI to measure the size of the heart attack.
The study found that symptom-to-balloon time was more strongly linked to heart attack size and patients’ clinical health after a heart attack than door-to-balloon time.
The size of the heart attack increased with longer symptom-to-balloon times, whereas longer door-to-balloon times were not notably related to heart attack size.
Older age, female sex, arterial hypertension, diabetes, and left circumflex artery as the culprit vessel was linked to longer symptom-to-balloon time.
For every 60-minute delay in symptom-to-balloon time, the one-year rate of death or hospitalization for heart failure was increased by 11%.
The findings suggest that major efforts to further shorten door-to-balloon times by 10 or 20 minutes might not translate to better PCI outcomes.
The analysis indicates the more important and meaningful focus should be to shorten the delays from symptom onset to arrival at hospitals that can perform PCI.
One author of the study is Gregg W. Stone, M.D., the director of academic affairs at Mount Sinai Heart Health System in New York City.
The study is published in Circulation: Cardiovascular Interventions.
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