BOSTON —
Among nearly 800 patients with acute PE whose data are recorded in the FlowTriever All-Comer Registry for Patient Safety and Hemodynamics (FLASH), a prospective multicenter registry of individuals treated with mechanical thrombectomy using the FlowTriever system (Inari Medical), shorter time from admission to mechanical thrombectomy was associated with significantly greater reductions in intraprocedural mean and systolic pulmonary artery pressures (PAP), greater reductions in the right ventricular/left ventricular (RV/LV) ratio, and longer 6-minute walk times at 6 months, reported Krunal H. Patel, MD, a pulmonary and critical care fellow at the Lewis Katz School of Medicine at Temple University Hospital in Philadelphia.
“Mechanical thrombectomy in the FLASH registry showed a mortality benefit. I think as time progresses and mechanical thrombectomy becomes more popular, we’re just going to need to figure out what is the ideal time for intervention,” he said during an oral abstract session at the American College of Chest Physicians (CHEST) 2024 Annual Meeting.
“There’s mortality benefit in any case whether the patient is high-risk or intermediate-high. This is a thought-provoking retrospective analysis that says that early intervention is probably better than doing it late, but regardless, the FLASH registry trial showed that early thrombectomy or thrombectomy in general shows positive mortality benefit,” Patel said in an interview.
He likened the challenge for pulmonary and critical care specialists to that of interventional cardiologists, who have determined that the ideal window for starting percutaneous coronary interventions is within 90 minutes of the patient’s arrival at the facility.
“I think we have to get our ‘door-to-balloon’ time for PE care,” he said.
Study Details
Patel and colleague Parth M. Rali, MD, FCCP, associate professor of thoracic medicine at Temple, conducted a retrospective review of data on 787 US patients in the FLASH registry for whom time to mechanical thrombectomy data were available. They stratified the patients into short and long time to mechanical thrombectomy groups, with “short” defined as ≤ 12 hours of presentation and “long” as > 12 hours.
They found that the median time to thrombectomy was 19.68 hours. In all, 242 patients (31%) were treated within the short window, and the remaining 545 patients (69%) were treated after at least 12 hours had passed.
Comparing clinical characteristics between the groups, the investigators noted that significantly more patients in the short time group vs long time group were categorized as high-risk (11.2% vs 6.2%; P = .0026). This difference is likely due to the need for greater urgency among high-risk patients, Patel said.
Patients in the short time group also had significantly higher baseline RV/LV ratios and lactate levels, but baseline dyspnea scores and pre-procedure median and systolic PAP were similar between the groups.
The mean time to thrombectomy was 6.08 hours in the short time group vs 34.04 hours in the long time group. Their respective median times were 6.01 and 24.73 hours.
The procedural time was similar between the groups, at 45 and 42 minutes, respectively.
The location of the treated thrombus was central only in 35.1% and 26.5% patients in the short and long time groups, respectively. Lobar-only thrombi were treated in 7.9% and 14.3%, respectively, and both central and lobar thrombi were treated in 57.0% and 59.2%, respectively.
Both 48-hour and 30-day all-cause mortality rates were similar between the groups (0.4%/0.2% and 0.5%/1.0%).
Patients in the short time group had slightly but significantly longer post-procedure hospital and intensive care unit stays, but 30-day readmission rates — whether for PE- or non-PE–related causes — were similar.
Where the differences between the groups really showed, however, were PAP reductions over baseline, with decline in median pressures of −8.7 mm Hg in the short group vs −7.2 mm Hg in the long group (P = .0008), and drops in systolic PAP of −14.4 vs −12.1 mm Hg, respectively (P = .0011).
In addition, reductions in RV/LV ratios from baseline were also significantly greater among patients whose thrombectomies had been expedited at the 48-hour, 30-day, and 6-month follow-up periods.
At 6 months, patients who had received mechanical thrombectomy within 12 hours also had significantly longer 6-minute walk distances (442.2 vs 390.5 m; P = .0032).