Imperative Care Reports Comparable Outcomes in Women and Men Following Symphony Thrombectomy for Intermediate-Risk Pulmonary Embolism
Imperative Care, a medical technology company focused on advancing the treatment of thromboembolic disease, has announced new findings from a pre-specified sex-specific analysis of the SYMPHONY-PE IDE Trial. The analysis, published simultaneously in the Journal of the Society for Cardiovascular Angiography & Interventions (JSCAI), found that women and men with intermediate-risk pulmonary embolism (PE) experienced substantial reductions in clot burden and improvements in right-heart function following treatment with the Symphony Thrombectomy System.
The findings were presented by Aymen Ahmed, MD, of Endeavor Health Cardiovascular Institute, at Transcatheter Cardiovascular Therapeutics (TCT) 2026. The results offer additional clinical evidence on the use of large-bore, pump-driven aspiration thrombectomy in women, a patient population in which concerns about bleeding and vascular complications have been raised in connection with procedures requiring large-bore vascular access.
The analysis showed that women entered the study with greater evidence of cardiac stress than men, despite having a similar initial clot burden. Nevertheless, both groups experienced meaningful improvements following thrombectomy, and their short-term clinical and safety outcomes were broadly comparable. The findings are relevant to physicians evaluating advanced treatment options for patients with intermediate-risk PE, particularly when considering whether procedural risks and treatment responses may differ according to sex.
The SYMPHONY-PE IDE Trial evaluated the Symphony Thrombectomy System, which uses aspiration technology to remove blood clots from the pulmonary arteries. The new analysis provides a closer examination of procedural and effectiveness outcomes in female and male participants, adding to the clinical evidence supporting the use of the 24F pump-driven aspiration platform.
Sex-Specific Analysis Addresses an Important Evidence Gap
Pulmonary embolism occurs when a blood clot, commonly originating in the deep veins of the legs or pelvis, travels through the bloodstream and blocks one or more arteries in the lungs. The obstruction can restrict blood flow through the pulmonary circulation, increase pressure on the right side of the heart and interfere with the body’s ability to deliver oxygen.
The severity of PE can vary considerably. Patients with high-risk PE may experience hemodynamic instability, including low blood pressure or shock, while those with intermediate-risk PE may remain relatively stable but show evidence of right-heart strain or other signs of cardiac stress. Intermediate-risk patients can require close monitoring because their condition may deteriorate, and physicians must assess the potential benefits and risks of available treatment approaches.
Treatment decisions depend on several factors, including the patient’s clinical condition, clot burden, right ventricular function, bleeding risk and likelihood of deterioration. Anticoagulation is an important component of PE management, while selected patients may be considered for advanced interventions intended to remove or reduce the obstructing clot.
However, questions remain about whether women and men experience different procedural risks or treatment responses when undergoing catheter-based interventions. Previous studies have raised concerns about potentially higher rates of bleeding and vascular complications among women undergoing procedures that require large-bore vascular access.
These concerns are particularly relevant to advanced pulmonary embolism interventions, which may involve the introduction of relatively large catheters into the venous system. Understanding whether women experience comparable safety and effectiveness outcomes is therefore important for physicians making treatment decisions.
The pre-specified sex-specific analysis of the SYMPHONY-PE IDE Trial was designed to examine these issues by comparing outcomes among female and male participants treated with the Symphony Thrombectomy System.
Study Evaluated 106 Patients Across 17 U.S. Centers
The analysis included a modified intention-to-treat (ITT) population of 106 patients enrolled across 17 clinical centers in the United States. Of the participants, 42 were women, representing 40% of the study population, while 64 were men, accounting for the remaining 60%.
The investigators assessed procedural and effectiveness outcomes, including changes in clot burden, right-heart function and pulmonary artery pressure. They also examined short-term clinical and safety outcomes following aspiration thrombectomy.
The Symphony Thrombectomy System was used to perform clot removal in both groups. The 24F Symphony aspiration catheter was utilized in 91% of women and 94% of men, demonstrating that the large-bore catheter was used at similar rates across the two populations.
This comparable use is important to the interpretation of the findings because it provides evidence from patients treated with the same general thrombectomy platform and catheter size. The analysis therefore offers insight into outcomes following 24F pump-driven aspiration thrombectomy in women and men.
The study also evaluated outcomes through 30 days following the procedure. Across both groups, investigators reported no deaths and no device-related serious adverse events during this follow-up period.
These safety findings are notable given the concerns that have previously been raised about large-bore vascular access in women. Although the sample size and follow-up period limit the conclusions that can be drawn, the absence of reported deaths or device-related serious adverse events in either group provides encouraging short-term evidence.
Improvements in Right-Heart Function Observed in Both Groups
One of the important measures examined in the analysis was the right ventricular-to-left ventricular (RV/LV) ratio. This measurement is commonly used in pulmonary embolism assessment to evaluate right-heart enlargement and strain.
When a pulmonary artery becomes obstructed by a clot, pressure within the pulmonary circulation can increase. The right ventricle must work harder to pump blood through the lungs, potentially resulting in enlargement or impaired function. An elevated RV/LV ratio can therefore indicate increased right-heart strain in patients with PE.
The analysis found that women and men experienced improvements in right-heart function following thrombectomy. At 48 hours, women had a significantly lower RV/LV ratio than men, with values of 1.03 compared with 1.14, respectively. The difference was statistically significant, with a P value of 0.006.
Importantly, the difference remained statistically significant after multivariable adjustment, with a P value of 0.010. This suggests that the observed difference was not fully explained by the other variables included in the adjusted analysis.
The finding is particularly relevant because women had demonstrated greater evidence of cardiac stress at baseline despite presenting with a similar initial clot burden. Following treatment, the lower RV/LV ratio observed among women at 48 hours indicates that the two groups did not experience identical measured outcomes, even though the overall clinical and safety results were broadly comparable.
The result should be interpreted in the context of the study’s size and design. It does not establish that women necessarily respond better to thrombectomy than men, nor does it demonstrate a long-term difference in clinical outcomes. Rather, it provides a specific finding from a pre-specified analysis that may help guide future research into sex-related differences in PE presentation and treatment response.
Pulmonary Artery Pressure Reduction Supports Procedural Effectiveness
The investigators also examined changes in mean pulmonary artery pressure, an important measure of pressure within the pulmonary circulation.
In patients with PE, blood clots obstructing pulmonary arteries can increase resistance to blood flow. This places additional pressure on the right ventricle and can contribute to cardiac strain. Reducing the obstruction through clot removal may help improve blood flow and reduce pressure within the pulmonary arteries.
The analysis found that women experienced a greater unadjusted percentage reduction in mean pulmonary artery pressure than men following thrombectomy. The reduction was 28% among women compared with 19% among men, a statistically significant difference with a P value of 0.02.
However, the association between sex and post-thrombectomy mean pulmonary artery pressure was not statistically significant after adjustment for other variables. This distinction is important because unadjusted comparisons may be influenced by differences in baseline characteristics or other factors.
The results therefore suggest that women experienced a greater reduction in mean pulmonary artery pressure in the unadjusted analysis, but the adjusted findings did not establish an independent association between sex and the post-procedure pressure measurement.
Taken together with the RV/LV ratio findings, the pulmonary pressure results indicate that aspiration thrombectomy was associated with improvements in important measures of cardiopulmonary function across both groups. They also demonstrate why more detailed analyses are needed to understand whether differences in baseline presentation influence measured responses following treatment.
Safety Outcomes Broadly Comparable Between Women and Men
Safety was a central consideration in the sex-specific analysis, particularly because women undergoing procedures that require large-bore vascular access have been identified in previous studies as potentially facing increased risks of bleeding and vascular complications.
The use of a 24F aspiration catheter makes the safety evaluation especially relevant. Large-bore access procedures require careful vascular management, and physicians must weigh the potential benefits of clot removal against the risks associated with the intervention.
In the SYMPHONY-PE analysis, no deaths or device-related serious adverse events were reported in either women or men through 30 days. The overall clinical and safety outcomes were broadly comparable between the groups.
These findings provide prospective clinical evidence that may help address concerns about the use of large-bore aspiration thrombectomy in women with intermediate-risk PE. They are also consistent with the study’s broader observation that women experienced substantial reductions in clot burden and improvements in right-heart function despite having greater evidence of cardiac stress at baseline.
Nevertheless, the results should not be interpreted as definitive proof that procedural risks are identical across sexes. The analysis involved 106 patients, including 42 women, and evaluated outcomes over a 30-day period. Larger studies with longer follow-up will be necessary to examine less frequent complications, longer-term clinical outcomes and potential differences in treatment response.
Investigators Highlight the Importance of Further Research
Arman Qamar, MD, MPH, senior and corresponding author of the study, Director of the Center for Cardiovascular Personalized Medicine and Co-Director of the Pulmonary Embolism Response Team at Endeavor Health Cardiovascular Institute, emphasized the importance of evaluating thrombectomy safety and effectiveness in women.
“Previous studies have raised concerns about higher rates of bleeding and vascular complications among women undergoing procedures requiring large-bore vascular access, including advanced pulmonary embolism interventions. These concerns make the safety and effectiveness of large-bore thrombectomy in women an important clinical question,” Dr. Qamar said.
He noted that the findings were encouraging because women entered the study with greater evidence of cardiac stress but still experienced substantial improvements following treatment.
“Our findings are particularly encouraging. Despite presenting with greater evidence of cardiac stress at baseline, women experienced substantial reductions in clot burden and improvements in right ventricular function, with clinical and safety outcomes broadly comparable to those observed in men. These prospective findings provide reassurance regarding the use of 24F pump-driven aspiration thrombectomy in women, while underscoring the need for larger studies to further evaluate sex-specific treatment responses and long-term outcomes,” Dr. Qamar added.
The comments underscore the clinical importance of examining outcomes in different patient populations rather than assuming that findings from one group will apply equally to all patients. Sex-specific analyses can help identify potential differences in disease presentation, procedural risk and response to treatment, providing physicians with additional information when selecting interventions.
Imperative Care Emphasizes Clinical Evidence and Treatment Decisions
Imperative Care Chairman and Chief Executive Officer Fred Khosravi said the analysis reflects the company’s commitment to generating clinical evidence to support the advancement of thrombectomy care.
“Generating meaningful clinical evidence is fundamental to advancing thrombectomy care,” Khosravi said. “As the first-in-field sex-specific analysis of a 24F pump-driven aspiration thrombectomy platform, we believe these findings address an important evidence gap in the treatment of women with pulmonary embolism and reinforce our commitment to advancing clinical science that helps physicians make informed treatment decisions and ultimately improve patient care.”
The company’s focus on clinical research is intended to support a better understanding of how its technologies perform across patient populations. Evidence from prospective clinical studies can help physicians assess procedural effectiveness, identify potential safety considerations and determine how an intervention may fit within existing treatment pathways.
The publication of the SYMPHONY-PE sex-specific analysis in JSCAI, alongside its presentation at TCT 2026, brings the findings to clinicians and researchers involved in cardiovascular and pulmonary embolism care.
Findings Add to Evidence for Symphony Thrombectomy System
The new analysis adds another dimension to the clinical evaluation of the Symphony Thrombectomy System in intermediate-risk PE. Its findings indicate that women and men treated with the system experienced substantial clot burden reduction and improvements in right-heart function, with broadly comparable short-term clinical and safety outcomes.
The analysis also identified specific differences between the groups. Women had significantly lower RV/LV ratios at 48 hours, including after multivariable adjustment, while their greater unadjusted reduction in mean pulmonary artery pressure was not statistically significant after adjustment.
These results provide useful information but do not resolve every question about sex-specific outcomes in pulmonary embolism treatment. Further research involving larger patient populations and longer follow-up will be needed to establish whether the observed differences have lasting clinical implications and to evaluate outcomes such as recurrent PE, bleeding complications, functional recovery and longer-term cardiovascular health.
For now, the findings provide additional prospective evidence supporting the evaluation of 24F pump-driven aspiration thrombectomy in women with intermediate-risk pulmonary embolism. They also reinforce the importance of including adequate numbers of women in clinical studies and examining outcomes by sex to ensure that treatment decisions are supported by evidence across patient populations.
As research into catheter-based PE interventions continues, studies such as the SYMPHONY-PE analysis may help physicians better understand the relationship between baseline cardiac stress, clot burden, procedural characteristics and post-treatment recovery. Continued clinical evaluation will be important in determining how aspiration thrombectomy can be incorporated into individualized care strategies for patients with pulmonary embolism.
About the SYMPHONY-PE IDE Trial
The SYMPHONY-PE IDE Trial (NCT06062329) was a prospective, multicenter, single-arm study evaluating the safety and efficacy of the Symphony Thrombectomy System in patients with acute intermediate-risk pulmonary embolism. The system incorporates continuous pump-driven aspiration with 24F and 16F catheter options. The trial enrolled 109 patients across 17 U.S. centers.
About the Symphony Thrombectomy System
The Symphony Thrombectomy System is a large-bore aspiration system designed to remove the guesswork from thrombectomy procedures, enabling more efficient, effective clot removal in patients with venous thromboembolism (VTE). Through real-time visualization inside the catheter and vessel, Symphony is designed to give physicians immediate insight into what is happening at every step of the procedure so they can make the right next move with confidence.
The system includes 16F and 24F catheters for smooth tracking, stability, and telescoping to reach distal anatomy; ProHelix® Mechanical Assist, designed to facilitate clot ingestion and avoid pulling a corked catheter across the heart when needed; the Symphony 24F Advance® Long Dilator for navigating through tortuous anatomy; and the Imperative Care Generator, a powerful aspiration pump.
For complete product information, including indications, contraindications, warnings, precautions and adverse events, visit: http://bit.ly/3pAaUlw.
About Imperative Care, Inc.
Imperative Care, headquartered in Silicon Valley, is a medical technology company focused on advancing the treatment of thromboembolic disease. Its commercial portfolio spans stroke and vascular thrombectomy and includes the Zoom Stroke System, Symphony Thrombectomy System and Prodigy Thrombectomy System.
Together, these technologies form an aspiration thrombectomy portfolio designed to enable physicians to remove blood clots across neurovascular and peripheral indications throughout the body, with a focus on improving procedural efficiency. Imperative Care is building on its established commercial platforms with the Telos Robotic Platform* to bring greater precision and standardization to procedures and expand access to lifesaving treatment.