Image courtesy of the
Medical College of Georgia
New research suggests that ultrasound-facilitated, catheter-directed, low-dose thrombolysis can produce positive results in patients with acute pulmonary embolism (PE).
In the SEATTLE II study, this treatment prompted significant decreases in thrombus burden, pulmonary hypertension, and the right ventricular-to-left ventricular (RV/LV) diameter ratio.
Major bleeds occurred in 10% of patients, but there were no cases of intracranial hemorrhage.
These results were published in JACC: Cardiovascular Interventions.
The SEATTLE II study was designed to evaluate ultrasound-facilitated, catheter-directed, low-dose thrombolysis using the EKOS EkoSonic® Endovascular System. The research was sponsored by EKOS Corporation, the company developing the system.
The trial included 150 patients diagnosed with acute massive (n=31) or submassive (n=119) PE. Patients received low-dose (24 mg) tissue plasminogen activator for 24 hours with a unilateral catheter or for 12 hours with bilateral catheters.
By 48 hours after treatment initiation, the mean RV/LV diameter ratio had significantly decreased, from 1.55 to 1.13 (P<0.0001).
The mean pulmonary artery systolic pressure decreased significantly as well, from 51.4 mm Hg to 36.9 mm Hg (P<0.0001).
And there was a significant decrease in modified Miller angiographic obstruction index score, from 22.5 to 15.8 (P<0.0001).
There were no intracranial hemorrhages and no fatal bleeding events. Major bleeds occurred in 15 patients (10%) and consisted of 1 severe bleed and 16 moderate bleeds.
Six of the major bleeds occurred in patients with comorbidities known to be associated with an increased risk of bleeding during thrombolytic therapy.
There were 3 serious adverse events that were considered potentially related to the EkoSonic Endovascular System. And 2 serious adverse events were potentially related to tissue plasminogen activator.
At 30 days post-treatment, there were 4 deaths. Three occurred in-hospital, and 1 was directly attributed to PE.
The researchers pointed out that 31 patients presented with massive PE, syncope, and hypotension. And all 31 survived the 30-day follow-up period.
“The SEATTLE II findings establish a new rationale for considering ultrasound-facilitated, catheter-directed, low-dose thrombolysis in both massive and submassive PE,” said study author Gregory Piazza, MD, of Brigham and Woman’s Hospital in Boston, Massachusetts.
“Without any intracranial hemorrhage and using a much-reduced lytic dose, a substantial and clinically meaningful reduction of the RV/LV ratio was achieved.”
