Stay up-to-date in pulmonary and critical care. No spam.
A handful of people with pulmonary embolism have absolute contraindications to anticoagulation. Authors here describe these as:
- Any prior intracranial hemorrhage,
- known structural intracranial cerebrovascular disease (eg, arteriovenous malformation),
- known malignant intracranial neoplasm,
- ischemic stroke within 3 months,
- suspected aortic dissection,
- active bleeding or bleeding diathesis,
- recent surgery encroaching on the spinal canal or brain,
- significant closed-head or facial trauma with radiographic evidence of bony fracture or brain injury.
For those with intermediate- or high-risk pulmonary embolism (submassive or massive PE) with such contraindications, the American Heart Association folks recommend catheter-based reperfusion procedures be performed if experienced staff are available. (Class IIa - IIb "C" recommendation, meaning a low level of evidence, mainly consensus opinion.)
There are numerous techniques and devices (Rheolytic Thrombectomy, Suction Thrombectomy, Rotational Thrombectomy), which you can see by skimming the free full text article.
What's the evidence? Slim to none, they say:
Catheter interventions have not been compared in a randomized trial with treatment with systemic thrombolysis or with anticoagulation alone, and current evidence is based on single-center case series.
Most (all?) of the existing data is tainted by the inclusion of many patients who also got catheter-directed thrombolytics. Authors also acknowledge that publication bias probably has resulted in an underestimation of the real-world complication rates from catheter based reperfusion procedures (periprocedural hemodynamic deterioration, distal embolization, pulmonary artery perforation, systemic bleeding complications, lung hemorrhage, pericardial tamponade, transient heart block or bradycardia, contrast-induced nephropathy, and access-related complications, including hematoma, pseudoaneurysm, or arteriovenous fistula). Whew, that's a mouthful.
Seems to me it would be very difficult to establish and maintain the case volume required to be an experienced center / operator, since these patients with true absolute contraindications to anticoagulation are (it seems) pretty uncommon, even at tertiary centers.
In practice (as in the case these authors cite of a person recently post-hemicolectomy), catheter directed approaches are probably more often used in people with relative contraindications to anticoagulation, and in conjunction with either heparin or with catheter-directed thrombolysis. This is believed anecdotally to result in lower rates of hemorrhage, but (to my knowledge) this has never been shown to be so.
Engelberger RP, Kucher N. Catheter-Based Reperfusion Treatment of Pulmonary Embolism. Circulation 2011;124:2139-2144. FREE FULL TEXT