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Mechanical Effects of Cardiovascular Drugs and Devices
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
For large blood clots lodged in peripheral arteries, such as those of the arms and legs, the device developed to remove the clot is the embolectomy balloon catheter.5 An embolectomy catheter is a balloon-tipped catheter used to remove blood clots, which have detached from the site of origin and migrated to another site in the vascular tree, where they become lodged in an artery. The catheter is inserted into a major artery and guided to the treatment site by using fluoroscopy and/or ultrasound imaging. The catheter tip is pushed through the clot, the balloon is inflated, and the device retracted, pulling the clot out through the insertion site. This procedure replaced a painful and risk surgery, decreasing the time of surgery to 1 hour and greatly reducing limb loss and the amount of pain during recovery. The most common mechanical injuries produced during an embolectomy procedure are relatively minor, consisting of the percutaneous insertion site and the disruption of the vessel endothelium where the balloon is applied. The embolectomy catheter is regulated as a Class II device under Subpart F: Cardiovascular Therapeutic Devices and must demonstrate conformance to performance controls, including dimensional verification, tensile strength of connections, balloon inflation/deflation time, fatigue and leakage tests, kink resistance, and torque strength of the device, as well as biocompatibility standards, to receive regulatory approval. The catheter must also demonstrate effective adherent clot removal, usually evaluated in animal studies. Previous studies have shown that while embolectomy produces partial injury to the endothelium (noted as partial denudation of the surface) in intact vessels, no apparent change in smooth muscle function results.7
EkoSonic® endovascular system and other catheter-directed treatment reperfusion strategies for acute pulmonary embolism: overview of efficacy and safety outcomes
Published in Expert Review of Medical Devices, 2020
Lukas Hobohm, Karsten Keller, Thomas Münzel, Tommaso Gori, Stavros V. Konstantinides
Beyond the clinical scenario of overt hemodynamic instability, up to one-third of patients with acute PE may be classified into the intermediate-risk category [5]. The management of these patients, who appear to be hemodynamically stable at presentation but show evidence of right ventricular dysfunction and/or elevated cardiac biomarker levels, is still the subject of debate. Routine primary reperfusion treatment, notably full-dose systemic thrombolysis, is not recommended, since the risk of potentially life-threatening bleeding complications appears unacceptably high compared to the expected hemodynamic and clinical benefits [5,12,13]. For several of these patients, catheter-directed treatment techniques, allowing local infusion of the thrombolytic agent or purely mechanical/suction embolectomy, may represent an attractive alternative treatment strategy. Recently, catheter-directed thrombolysis, particularly when used in combination with ultrasound energy, showed promising results in prospective randomized and cohort trials [14–16]. In the present article, we review the available data on catheter-directed treatment of acute PE, putting current strengths, weaknesses and challenges into perspective, and providing an outlook on the trials and data that will be needed to successfully validate and possibly establish these treatment options in the following years.
Review of pulmonary emboli and techniques for their mechanical removal to inform device design
Published in Journal of Medical Engineering & Technology, 2020
Jessica Brand, Roger McGowan, Amit Nimunkar
Surgical embolectomy is an open surgery where an embolus is removed from the right atrium, right ventricle, or pulmonary arteries. This method is only used when there are contraindications to thrombolytics, when catheter-based clot removal has failed, or in specific cases with cardiac complications such as atrial septal defects or free-floating cardiac emboli [5,9]. It is generally less effective than CDT for hemodynamically unstable patients, though remains a reasonable option for some. However, its associated mortality rates are still debated [9].