Background and Purpose:
In cryptogenic stroke (CS), paradoxical embolus has been suggested as a stroke mechanism. A prior study found a significant rate of pelvic deep venous thrombosis (DVT) using magnetic resonance venography (MRV). We sought to evaluate the yield of diagnostic tests for lower extremity (LE) and pelvic DVT in stroke patients with patent foramen ovale (PFO) and in the subset with CS.
Methods:
A single center retrospective study was performed to identify consecutive ischemic stroke or TIA patients with PFO who underwent contrast-enhanced 3D pelvic MRV imaging (Ablavar, Lantheus Medical Imaging, N. Billerica, MA) between 2009 and 2013 as part of an inpatient diagnostic evaluation. Results of pelvic MRV, LE Doppler ultrasound (US) as well as clinical data were abstracted. Ischemic subtype was retrospectively assigned using the Causative Classification System (CCS). Patients with possible cardio-aortic embolism and undetermined cause by CCS were classified as CS. We estimated point estimates and 95% confidence intervals (CI) for DVT prevalence among stroke subtypes using the Wald method and compared these using Chi-square tests.
Results:
Of 130 patients who met study criteria, mean age was 56 +/- 17 years and median time from admission to MRV was 2 days (IQR 1-3). Overall DVT prevalence was 7.7% (95% CI, 4.1 to 13.7); the prevalence of pelvic DVT was 1.6% (95% CI, 0.07 to 5.8) and that of LE DVT was 7.2% (95% CI, 3.7 to 13.3). Of the patients with pelvic DVT (n=2), one patient also had a LE DVT by US. When MRV or US was obtained within 72 hours following admission, the prevalence of pelvic DVT was 2.1% (95% CI, 0.12 to 7.7) and that of LE DVT was 7.8% (95% CI, 3.8 to 14.8). Comparing patients with CS (n=97) to other subtypes (n=33), there was no difference in the prevalence of pelvic DVT (2.1% vs. 0%, P=1), LE DVT (6.3% vs. 10.3%, P=0.43) or any DVT (7.2% vs. 9.1%, P=0.71).
Conclusion:
Patients with CS and PFO have similar prevalence of DVTs compared to other stroke subtypes. The majority of detected DVTs were in LE veins rather than pelvic veins. Only a single patient with a pelvic DVT did not have a coexistent LE DVT. Our results suggest that the utility of pelvic MRV may be much lower than previously reported.
Large paradoxical embolus through a patent foramen ovale following arteriovenous graft thrombectomy
