Contact-to-Device Delays and Higher Mortality Seen in Women vs Men Presenting With STEMI

Even when accounting for total ischemic time, women with STEMI have more delays to treatment than men and are about twice as likely to die, a new study shows. The importance of contact-to-device time, say researchers, helps illuminate the problems inherent in focusing solely on door-to-balloon (D2B) time and represents an important future target for quality improvement.

“The door-to-balloon metric was a great one,” Robert O. Roswell, MD (New York University School of Medicine, New York, NY), told TCTMD. “But shortening it more and more doesn’t seem to impact mortality. Contact-to-device time may be where the focus should be, and where we can impact mortality and morbidity in patients who have STEMI.”

The 2013 full-scale revision of the guidelines for STEMI management first proposed that the D2B benchmark be changed to the perfusion metric of contact-to-device (C2D) time, which would include any prehospital location and virtually any type of device (balloons, coronary stents, wires, aspiration catheters, etc). This shift put the emphasis on early assessment, care, and transport, and recommended a C2D time of 90 minutes or less. But while the literature is replete with D2B analyses, little is known about patient outcomes when C2D is considered.

In their study, published online last week in the Journal of the American Heart Association, Roswell and colleagues found that among 102,515 patients included in the National Cardiovascular Data Registry from July 2008 through December 2014, C2D times overall were longer for women than men (median 80 vs 75 minutes; P < 0.001), even under optimal conditions when the mode of transportation to the hospital was emergency medical services (EMS) with transmission of ECG to the receiving hospital (median 83 vs 79 minutes; P < 0.001).

More than half of all patients in the study were transported to hospitals by ambulance (61.5%), and this was more often true of women than men (65.9% vs 59.8%). However, prehospital ECG transmission among patients who reached the emergency room by ambulance was more commonly performed for men than for women (73.9% vs 70.9%).

When patients reached the hospital, women faced double the mortality rate of men (4.1% vs 2.0%; P < 0.001) and higher rates of heart failure, cardiogenic shock, stroke, and cardiac arrest. Mortality was closely aligned with C2D time such that for every 5-minute increase, the adjusted OR for mortality was 1.04 (95% CI, 1.03-1.06) for women and 1.07 (95% CI, 1.06–1.09) for men (P for sex by C2D interaction = 0.001).

In the study, total ischemic times were more than 20 minutes longer in women than in men (161 vs 145 minutes; P < 0.001) and women had about 10 minutes longer, on average, symptom-onset-to-first-medical-contact times (75 vs 63 minutes; P < 0.001).

New Metric’s Time Has Come

Early D2B studies also showed a disparity with regard to gender among STEMI patients that improved with focused national quality initiatives including Mission: Lifeline and the D2B Alliance. “By systemically studying why prehospital assessment is delayed in women versus men, we might also come up with ways of addressing this disparity and move forward where we have more parity between genders,” Roswell noted.

He added that going forward “we should absolutely be using first medical contact-to-device time” rather than D2B since the latter “is negating how long it took for the patient to get from their house to the ER, from the ambulance to the house, and how long it took for them to activate the event. We know that all of those things that happen prehospital really impact mortality. Total ischemic time is the best marker to tell us how we’re doing in terms of restoration of coronary flow and is more likely to impact mortality [than D2B alone].”

The mortality from STEMI and the difference between genders is quite striking. Robert O. Roswell

Looking at C2D time also raises the possibility of finding additional explanations for STEMI treatment delays that may not be known, Roswell told TCTMD. Among the things it could identify are: localities where EMS has difficulty finding patients, communications issues between EMS and patients, and reasons for reluctance on the part of some patients to go with EMS. “There are so many scenarios and so many differences that need to be parsed out,” he observed. “The mortality from STEMI and the difference between genders is quite striking. It needs to be addressed because it is actually quite alarming.”

Additionally, education is a key component needed for change, Roswell said. This includes raising awareness of angina and MI in women, and educating physicians to increase their levels of suspicion with regard to potential heart disease in female patients.