Intrapulmonary Shunt Is a Potentially Unrecognized Cause of Ischemic Stroke and Transient Ischemic Attack

Abushora, Mohannad Y.; Bhatia, Nirmanmoh; Alnabki, Ziad; Shenoy, Mohan; Alshaher, Motaz; Stoddard, Marcus F.

doi:10.1016/j.echo.2013.04.004

Cited by 41 publications

(48 citation statements)

References 26 publications

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“…We and others have postulated that IPAVA may be a facilitator of embolic stroke (1,25). By compromising the lung as a biological filter, these vessels may permit microemboli to bypass the lung and cause neurological sequelae.…”

Section: Discussionmentioning

confidence: 99%

Exercise- and hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses is reduced in older adults

Norris

Mangum

Duke

et al. 2014

Journal of Applied Physiology

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Mean pulmonary arterial pressure (Ppa) during exercise is significantly higher in individuals aged ≥50 yr compared with their younger counterparts, but the reasons for this are unknown. Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) can be detected during exercise or while breathing hypoxic gas mixtures using saline contrast echocardiography in almost all healthy young individuals. It has been previously hypothesized that a lower degree of exercise-induced blood flow through IPAVA is associated with high Ppa during exercise. This association may suggest that individuals who are known to have high Ppa during exercise, such as those ≥50 yr of age, may have lower blood flow through IPAVA, but the presence and degree of exercise-induced blood flow through IPAVA has not been specifically studied in older populations. Using transthoracic saline contrast echocardiography, we investigated the potential effects of age on exercise-induced blood flow through IPAVA in a cross-section of subjects aged 19-72 yr. To verify our findings, we assessed the effects of age on hypoxia-induced blood flow through IPAVA. Age groups were ≤41 yr (younger, n = 16) and ≥50 yr (older, n = 14). Qualitatively measured exercise- and hypoxia-induced blood flow through IPAVA was significantly lower in older individuals compared with younger controls. Older individuals also had significantly higher pulmonary arterial systolic pressure and total pulmonary resistance (TPR) during exercise. Low blood flow through IPAVA was independently associated with high TPR. The reasons for the age-related decrease in blood flow through IPAVA are unknown.

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Section: Discussionmentioning

confidence: 99%

Exercise- and hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses is reduced in older adults

Norris

Mangum

Duke

et al. 2014

Journal of Applied Physiology

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“…Benedik et al (2011) reported on transesophageal echocardiograms with contrast as well as using contrasted transcranial Doppler ultrasonography and reported potential shunting in 7/26 (27%) of controls compared with 11/23 (48%) of children with stroke or TIA (without SCD), excluding those with other identified aetiologies for stroke. Intrapulmonary shunting alone was an independent predictor of cryptogenic stroke or TIA in adults without SCA compared to controls (OR 2.6 (CI 1.6–4.2)) (Abushora, et al, 2013). Prothrombotic states predispose to paradoxical embolization in adult patients with potential intracardiac shunting (Hassell, 2005; Giardini, et al, 2004; Karttunen, et al, 2003) and the Valsalva manoeuvre, which can increase right heart pressures and favour RLS, is common at the onset of stroke in adults without SCA (Karttunen, et al, 2003; Bogousslavsky, et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

Increased prevalence of potential right‐to‐left shunting in children with sickle cell anaemia and stroke

et al. 2016

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“Paradoxical” embolization via intracardiac or intrapulmonary right-to-left shunts (RLS) is an established cause of stroke. Hypercoagulable states and increased right heart pressure, which both occur in sickle cell anaemia (SCA), predispose to paradoxical embolization. We hypothesized that children with SCA and overt stroke (SCA+stroke) have an increased prevalence of potential RLS. We performed contrasted transthoracic echocardiograms on 147 children (aged 2–19 years) with SCA+stroke) mean age 12.7±4.8 years, 54.4% male) and a control group without SCA or stroke (n=123; mean age 12.1±4.9 years, 53.3% male). RLS was defined as any potential RLS detected by any method, including intrapulmonary shunting. Echocardiograms were masked and adjudicated centrally. The prevalence of potential RLS was significantly higher in the SCA+stroke group than controls (45.6% vs. 23.6%, p<0.001). The odds ratio for potential RLS in the SCA+stroke group was 2.7 (95% confidence interval: 1.6–4.6) vs controls. In post hoc analyses, the SCA+stroke group had a higher prevalence of intrapulmonary (23.8% vs. 5.7%, p<0.001) but not intracardiac shunting (21.8% vs. 18.7%, p=0.533). SCA patients with potential RLS were more likely to report headache at stroke onset than those without. Intrapulmonary and intracardiac shunting may be an overlooked, independent and potentially modifiable risk factor for stroke in SCA.

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“…Chronic pulmonary embolism causes pulmonary hypertension and hypoxia that enlarges small intrapulmonary arteriovenous anastomoses [20, 23, 24]. Intrapulmonary shunting is being increasingly recognized as an etiology of paradoxical embolism and stroke/TIA [14, 15]. …”

Section: Discussionmentioning

confidence: 99%

“…It is possible that patients with thrombogenic leads developed intrapulmonary shunts due to chronic pulmonary embolization. Paradoxical embolism through intrapulmonary shunts is increasingly recognized as an etiology of stroke/TIA [14, 15]. Since there was no way to retrospectively confirm the anatomic presence of small PFOs, intrapulmonary shunts, and thrombus burden on leads, we evaluated the association of lead characteristics with stroke/ TIA in all CIED patients.…”

Section: Introductionmentioning

confidence: 99%

Implanted endocardial lead characteristics and risk of stroke or transient ischemic attack

Vaidya

DeSimone

Asirvatham

et al. 2014

J Interv Card Electrophysiol

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Introduction Patent foramen ovale (PFO) has been recently implicated as a strong predictor of stroke or transient ischemic attack (TIA) in patients with implanted pacemaker or defibrillation leads. Leads in the right heart can form thrombi that embolize to the pulmonary circulation and raise pulmonary pressure. This increases right-to-left shunting through PFO or intrapulmonary shunts and can result in paradoxical embolism. We sought to determine whether certain lead characteristics confer a higher thrombogenic risk resulting in stroke/ TIAs in patients either with or without a PFO. Methods We retrospectively analyzed 5,646 patients (mean age 67.3±16.3 years, 64 % male) who had endocardial device leads implanted in 2000–2010. We performed univariate and multivariate-adjusted proportional hazards models to determine association of lead characteristics with stroke/TIA during follow-up. Results On univariate analysis, passively fixated tined leads were associated with more stroke/TIAs (HR 1.77, 95 % CI 1.27, 2.47; p<0.001), whereas presence of defibrillation coil was associated with fewer stroke/TIAs (HR 0.59, 95 % CI 0.42–0.84; p=0.003). Number of leads per patient, presence of atrial lead, maximum lead size, tip shape, and type of insulating material were not associated with stoke/TIA. On multivariate analyses adjusting for age, sex, diagnosis of PFO, and prior history of stroke/TIA, the presence of tined leads was associated with stroke/TIA (HR 1.41, 95 % CI 1.00–1.97; p=0.049). Defibrillation coils were no longer associated with lower stroke/TIA on multivariate analysis. Conclusions Most physical characteristics of contemporary leads do not impact rate of stroke/TIA among patients receiving implantable devices. The presence of a PFO is a major risk factor for stroke/TIA in patients with endovascular leads.

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Intrapulmonary Shunt Is a Potentially Unrecognized Cause of Ischemic Stroke and Transient Ischemic Attack

Cited by 41 publications

References 26 publications

Exercise- and hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses is reduced in older adults

Exercise- and hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses is reduced in older adults

Increased prevalence of potential right‐to‐left shunting in children with sickle cell anaemia and stroke

Implanted endocardial lead characteristics and risk of stroke or transient ischemic attack

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