Why does a hospital track the number of minutes between a stroke patient's arrival and the start of a thrombectomy procedure? The answer lies in how brain tissue responds to interrupted blood flow: neurons in the affected territory are commonly reported to be lost at a significant rate for every minute a large vessel occlusion remains untreated. This reality is why stroke systems of care place such emphasis on "door-to-groin time" — the interval from hospital arrival to arterial access for mechanical thrombectomy — as a core performance benchmark. Reducing this interval requires more than physician skill; it requires a coordinated stroke pathway spanning prehospital triage, in-hospital workflow, and interfacility transfer protocols.
What Does Door-to-Groin Time Actually Measure?
Door-to-groin time begins when a patient arrives at a hospital's entrance or emergency department and ends when the interventional team achieves arterial access, typically at the common femoral or radial artery, to begin the thrombectomy procedure. This single metric reflects the cumulative efficiency of triage, imaging acquisition, neurology consultation, and transport to the angiography suite. Because each of these steps can introduce delay, comprehensive stroke centers commonly track door-to-groin time as a quality indicator and work to shorten it through process redesign rather than by rushing any individual clinical decision.
How Do Comprehensive Stroke Centers Structure Their Stroke Pathway?
A comprehensive stroke center is generally organized around a standardized stroke pathway that activates automatically once a possible large vessel occlusion is identified, often through prehospital notification from emergency medical services. This pathway commonly includes pre-arrival mobilization of the stroke team, direct-to-CT-scanner routing that bypasses the traditional emergency department triage desk, and simultaneous notification of the neurointerventional team so that the angiography suite is prepared before imaging is even complete. Parallel processing of these steps, rather than a sequential one-after-another workflow, is generally the single largest contributor to shortened door-to-groin times.
Why Do Transfer Protocols Matter for Patients at Non-Thrombectomy Hospitals?
Many patients experiencing a large vessel occlusion first present to a hospital that can administer clot-dissolving medication but cannot perform mechanical thrombectomy on-site. In these cases, standardized transfer protocols between the initial hospital and a comprehensive stroke center become the primary determinant of how quickly the patient reaches definitive endovascular care. Effective transfer protocols typically include pre-arranged imaging-sharing agreements, direct physician-to-physician handoff calls, and pre-alerted receiving teams so that the transferring ambulance or helicopter can proceed directly to the angiography suite rather than through a second emergency department evaluation. Regions that formalize these agreements in advance, rather than negotiating them case by case, generally see more consistent transfer times.
Mobile Stroke Units and Prehospital Innovations Within Stroke Systems of Care
Some stroke systems of care have incorporated mobile stroke units, which are specially equipped ambulances carrying CT scanners and telemedicine links to a remote stroke neurologist. These units allow imaging and initial diagnosis to begin before the patient ever reaches a hospital, which can meaningfully compress the overall timeline for patients who are candidates for thrombectomy. While not every region has access to this resource, its use illustrates the broader principle underlying stroke systems of care: shifting diagnostic and coordination steps as early as possible in the patient's journey, rather than concentrating them all after hospital arrival.
The Role of Devices Within a Time-Sensitive Thrombectomy Workflow
Once arterial access is achieved, the speed and efficiency of the mechanical thrombectomy procedure itself also contributes to overall outcomes, alongside the systems-level factors described above. Thrombectomy devices, including stent retriever and aspiration catheter systems, are designed to restore blood flow through the occluded artery once the interventional team is ready to proceed. The systems-level workflow described in this article and the device-level engineering used during the procedure are complementary factors, and both are subjects of ongoing quality improvement within stroke care programs. More information on devices used in these procedures is available through INVAMED's neurovascular interventions category page.
How do mobile stroke units fit into the broader stroke pathway?
Mobile stroke units bring CT imaging and specialist telemedicine consultation directly to the patient's location, allowing diagnostic steps to begin before hospital arrival. This can shorten the overall time to treatment for patients who are candidates for thrombectomy or clot-dissolving medication. Availability of mobile stroke units varies significantly by region and healthcare system.
Device availability and regulatory status vary by country. Please contact INVAMED or your authorized local distributor for current regulatory information applicable to your region.