Most significant, the Turkish doctors did extensive measurements of microvascular function -- blood flow through the smallest heart vessels. They found that it was much better than in trial participants who did not get streptokinase.
That was a different result from previous research, Garratt said. "Then, we were looking at how the heart pumped blood," he said. "We didn't find a difference."
That was ultimately true in the Turkish study. After six months, "there was no evidence of a difference between the two study groups in left ventricular size or function," the researchers wrote, referring to the blood-pumping chamber of the heart.
"If you're interested in microvascular flow as an endpoint, this is an approach worth pursuing," Garratt said. "There is some evidence that improving microvascular flow improves outcome."
But even then, streptokinase may not be the best clot-preventing drug to use, Garratt said. "It has probably the worst bleeding rate out there," he said. "When we did this before, we saw lots of bleeding, and that is a significant limitation. Even if you show that improved microvascular flow is beneficial in the long term, bleeding is a problem."
The Turkish study also was a very small study, noted Dr. Jan J. Piek, professor of cardiology at the Academic Medical Center in Amsterdam, the Netherlands, who wrote an accompanying editorial in the journal. "We have to be a little bit careful, because they studied only 41 patients," he said. "I would consider it a hypothesis-generating study that has to be tested in a larger randomized trial."
Participants in such a trial would have to be chosen carefully, Piek said. "I would focus more on the uniform selection of patients," he said.
"Those who would benefit most would be patients with large myocardial infarctions [heart attacks]. They would be the most appropriate on whom to test this technique," Piek suggested. "The trial would have to be done in a sensitive setting, including only patients with larger infarcts, rather than the non-uniform selection of patients for this trial," he added.
More information
Learn more about angioplasty from the U.S. National Library of Medicine. |
