Introduction:
Pulmonary-arteriovenous-fistulas (PAVFs) are pathologic right-to-left shunts resulting in paradoxical embolism causing acute-ischemic-stroke (AIS). Recent single-center studies have identified that in patients with AIS associated with PAVF (AIS-P), traditional stroke risk-factors are not prominent and instead stroke-risk is associated with low serum iron. Single-centre studies have the risk of introducing a selection bias, while multicentre trials are challenging since PAVF still remains a rare and under-recognised entity. We thus seek epidemiological validation of such stroke predictors in patients with PAVF.
Methods:
We conducted a retrospective analysis of all AIS-admissions within the Nationwide-Inpatient-Sample (NIS) database (2005-2014). Baseline characteristics were compared across AIS populations [AIS-P (with PAVF) and R(routine)-AIS (without PAVF)]. We also compared morbidity, mortality and management trends of AIS in patients with and without PAVF.
Results:
Of 4,271,910 patients admitted with AIS, 822 (0.02%) were diagnosed with a PAVF. Over this decade the prevalence of PAVF per million AIS-admissions, rose from 197 to 368 (P
trend
=0.026). Patients with PAVF were younger with a median age (IQR) of 57.5 (42.2 -70.4) years
vs.
72.5 (60.8-82.1) years (p<0.001); but had comparable age-adjusted inpatient morbidity (χ
2
p=0.71) and all-cause mortality (χ
2
p=0.26). On multivariate analyses, the odds ratios (95% confidence-interval) favouring PAVF as the cause for AIS were 9.0 (6.79-11.94) for hypoxemia, 4.64 (3.84-5.60) for patent-foramen-ovale, 4.52 (3.42-5.97) for pulmonary hypertension, 4.07(2.23-7.44) for epistaxis, and 2.12 (1.60-2.82) for iron deficiency anaemia [all p-values <0.001].
Conclusion:
Pulmonary-arteriovenous-fistula related AIS represents a significantly younger demographic, which suffers inpatient morbidity and mortality comparable to routine ischemic-stroke. They carry a unique set of stroke-risk markers, including treatable conditions such as iron deficiency anemia. Further studies are needed to examine a causal role for such markers on ischemic-stroke risk in this cohort.
Pulmonary arteriovenous fistulas in patients with left isomerism and cardiac malformations