Pulmonary embolism (PE) continues to be the third cause of cardiovascular mortality. The current clinical guidelines recommend anticoagulation in intermediate risk patients presenting right ventricular dysfunction. However, mortality associated to this condition ranges from 3 to 15%, which drives the search for therapeutic alternatives to improve prognosis and management.
Prior studies on endovascular therapies such as large bore mechanical thrombectomy (MT) and catheter-directed thrombolysis (CDT) have shown promising results, but they have never been compared directly.
The PEERLESS is the first randomized study to look into thrombectomy systems and the first to compare these advanced therapies directly. It is an open, randomized, multicenter, international study, including patients with acute PE at intermediate risk. These patients presented a clot in the main or lobar pulmonary arteries, with acute symptom onset within the last 14 days, and one intervention carried out within 72 hours of diagnosis. Those who could not receive anticoagulation, had a thrombus in transit, life expectancy ≤90-day, or pulmonary systolic pressure ≥70 mmHg were excluded.
Patients were randomized 1:1 and were followed up to 30 days. The MT arm was treated with the FlowTriever system (Inari), while the CDT arm was treated with devices such as the EKOS, and infusion catheters (Cragg-McNamara, Uni-Fuse and Fountain), in addition to pharmacomechanical thrombolysis with BASHIR. There was no control group treated only with anticoagulants.
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The primary endpoint was a hierarchical assessment assessed using a win ratio including: of all-cause death, intracranial hemorrhage, major bleeding, clinical deterioration and/or escalation to bailout, and postprocedural ICU admission and length of stay.
In total, the study included 550 patients, 274 treated with MT and 276 with CDT, in 57 centers from 3 countries. Participant mean age was 63.7, and 54.4% were men. 94.7% presented elevated troponin, which indicated intermediate-high risk and 26.4% had VTE-BLEED ≥2. Only 4.2% presented a relative contraindication for thrombolytics.
The CDT arm was treated with bilateral catheters in 92% of cases, with 16 mg mean tPA and 14.5 hrs. mean infusion time. EKOS was used in 59.8% of cases.
Primary end point significantly favored MT vs CDT, with 5,01win ratio (CI 95%: 3.68–6.97; P<0.001). There were significant differences in two of the five components: lower rate of clinical deterioration or need for bailout therapy (1.8% vs 5.4%; P=0.04) and less use of ICU (P<0.001). There were no significant differences in all-cause mortality (0.0% vs 0.4%; P=1.00), major bleeding (6.9% vs 6.9%; P=1.00) or the other win ratio components.
30-day mortality resulted similar between both groups (0.4% vs 0.8%; P=0.62), and neither were there differences in readmissions for PE (0.0% vs 0.8%; P=1.00).
The authors concluded that the PEERLESS study reached the primary end point, which was associated to lower rate of clinical deterioration, lower need for bailout therapy, less use of ICU, better respiratory indices, lower symptom score and less general readmissions.
Presented by Wissam A. Jaber at Late-Breaking Trials, TCT 2024, October 27-29, Washington, EE.UU.
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