New Haven, CT - Reducing door to balloon times for primary PCI patients does appear to improve mortality even if patients have had MI symptoms for several hours, a new study suggests [1].

The study, published in the June 6, 2006 issue of the Journal of the American College of Cardiology, was conducted by a group led by Drs Robert McNamara and Harlan Krumholz (Yale University School of Medicine, New Haven, CT).

Krumholz told heartwire: "This should be a call to action to all hospitals to improve their systems so that primary angioplasty can be done faster in all patients. Everyone needs to get the message that universally reducing door-to-balloon times will likely result in many lives being saved."

In the paper, the authors explain that while time to reperfusion for MI patients treated with thrombolysis is well known to influence mortality, studies have found conflicting results regarding the relationship between mortality and time to reperfusion with primary PCI.

Although some studies have suggested that time to reperfusion is important for all MI patients undergoing primary PCI, others have found that rushing the patient into the cath lab translates into lower mortality only in certain subgroups, such as high-risk patients or those presenting within two hours of symptom onset, and some studies have failed to find any association between time to primary PCI and mortality.

They note that current ACC/AHA guidelines recommend door-to-balloon times of 90 minutes or less for primary PCI patients, but only a minority of patients are actually treated within this time period, and this pattern has not changed recently. They suggest that the perception that time to reperfusion is less important in PCI than with thrombolysis may contribute to the current inertia in performance.

To shed more light on this issue, they analyzed data from the US National Registry of Myocardial Infarction (NRMI) on door-to-balloon times and mortality in patients with STEMI admitted from 1999 to 2002. The analysis included data on 29 222 MI patients treated with primary PCI within six hours of presentation. Results showed that longer door-to-balloon times were associated with increased in-hospital mortality.

Adjusted for patient characteristics, the study found that patients with door-to-balloon time of more than 90 minutes had an increased risk of dying compared with those who had door-to-balloon times of less than 90 min.

In subgroup analyses, increasing mortality with increasing door-to-balloon time was seen regardless of how long patients had been experiencing symptoms before presentation and regardless of the presence or absence of high-risk factors.

Commenting on these results, McNamara said: "There is a belief among some clinicians that patients presenting late will not benefit from faster door-to-balloon time (the 'cow-is-out-of-the-barn' philosophy). We were able to show that door-to-balloon time matters for all patients, regardless of time to presentation, and for both low- and high-risk patients."

In an interview with heartwire, Krumholz said he was confident that these results were real, although they came from an observational study. "They are consistent enough with what we already know, and it makes sense that the sooner the artery is opened the better the outcome."

Whatever your risk, if somebody offered you an angioplasty in either one hour or two hours, no one is going to choose two hours.

"It is amazing to me that we are still debating whether we need to speed up the process of primary PCI. If you were having a heart attack, would you seriously say that you wouldn't mind waiting a while before they opened up your artery? Okay, some previous studies have questioned whether speeding up the process benefits all primary PCI patients, but we have two choices: we can keep going back and forth arguing about it, or we can fix it and shorten delays for all patients knowing that at least a subgroup of patients will benefit and probably everyone will.

"In our study, we saw a benefit for all groups. Yes, of course, the higher-risk patients saw the greatest benefit from faster treatment, but that is to be expected. And even the lowest-risk patients saw a sizable relative benefit—remember, this is mortality we are talking about, and you are not going to see a huge absolute reduction in mortality in low-risk patients because few of them die in any case. But if I were a low-risk patient, I would still want to be treated fast. Whatever your risk, if somebody offered you an angioplasty in either one hour or two hours, no one is going to choose two hours."

Dr Jeffrey Cavendish (Naval Medical Center, San Diego, CA), who was not connected with this study, said the results emphasized the importance of streamlining hospital procedures. "The main message that this study reinforces is not only the concept of 'time is muscle,' but that 'time is life,' " he commented.

"Emergency medical services [EMS] and hospitals throughout this country must do better to create a more seamless system to get patients into the catheterization lab in the shortest amount of time. We need a collaborative effort with EMS, emergency departments, nursing, cardiac catheterization lab staff, and cardiologists all working together to shorten door-to-balloon times to less than 90 minutes for all patients," Cavendish added.