Contrast echocardiography grading predicts pulmonary arteriovenous malformations on CT.

BACKGROUND: Untreated pulmonary arteriovenous malformations (PAVMs) can present with life-threatening complications. Agitated saline solution transthoracic contrast echocardiography (TTCE) has been recommended as the screening test of choice for PAVMs in hereditary hemorrhagic telangiectasia (HHT). A TTCE grading system has been proposed but not validated. The aim of this study was to determine the positive predictive value (PPV) of TTCE grades for the presence of PAVMs on CT. METHODS: A blinded retrospective review was conducted. All patients screened at the Toronto HHT Center (June 2002 to September 2004) with positive TTCE results were included. TTCE results were scored for delay (number of cardiac cycles) before appearance of microcavitations in the left atrium and graded for intensity of opacification. Grade 1 indicates minimal left ventricular opacification, grade 2 indicates moderate opacification, grade 3 indicates extensive opacification without outlining the endocardium, and grade 4 indicates extensive opacification with endocardial definition. Thoracic CT was performed in all patients, and results were scored as positive, negative, or indeterminate for PAVMs. RESULTS: Of 155 patients screened for PAVMs, 104 had positive TTCE results. Complete data were available for 90 patients (87%). Mean age was 45 years; 62% were female. Seventeen percent of patients screened and 27% of patients with positive TTCE results had CT detectable PAVMs. There was a significant association between TTCE grade and presence of PAVMs on CT (p < 0.0001). The PPV of grades 1, 2, 3, and 4 were 0.02 (95% confidence interval, 0.00 to 0.06), 0.25 (95% confidence interval, 0.06 to 0.44), 0.56 (95% confidence interval, 0.23 to 0.88), and 1.0 (95% confidence interval, 1.0 to 1.0), respectively. CONCLUSIONS: Increased shunt grade predicts increased probability of PAVMs and may be used to guide decisions in the screening algorithm for PAVMs.

Reperfusion of pulmonary arteriovenous malformations after embolotherapy.

PURPOSE: To describe the mechanisms and risk factors associated with reperfusion of successfully treated pulmonary arteriovenous malformations (PAVMs) after embolotherapy. MATERIALS AND METHODS: Among 112 consecutive patients with PAVMs treated by embolotherapy, 19 patients were identified who had 33 angiographically confirmed reperfused PAVMs. A retrospective analysis of computed tomography (CT) and angiography was performed in patients with documented reperfused PAVMs in which reperfused PAVMs were compared with nonreperfused PAVMs. CT images were examined for persistence of the aneurysm and/or draining vein after initial embolotherapy and correlated with angiography to determine the mechanism of reperfusion. PAVM and embolic agent characteristics (eg, feeding artery size and number; PAVM location; coil size, number, and location) were evaluated for association with reperfusion. The outcomes of repeat embolotherapy for reperfused PAVMs were evaluated. RESULTS: The PAVM aneurysm and/or draining vein persisted on CT after initial embolotherapy in all reperfused PAVMs and resolved in all nonreperfused PAVMs (in patients with nondiffuse PAVMs). Recanalization was the mechanism of reperfusion in 88%. Reperfusion was associated with the use of a single coil (P < .0001), oversized coils (P < .0001), coil placement more than 1 cm from the aneurysm (P < .0001), and increased feeding artery size (P < .001). Repeat embolotherapy for reperfused PAVMs was technically successful in 94% of cases. In the remaining 6% of cases, insufficient feeding artery length prevented safe repeat treatment. After a mean follow-up of 41 months, 42% of reperfused PAVMs in our series have been successfully treated again and occluded. CONCLUSIONS: Recanalization is the most common mechanism of PAVM reperfusion. Increased feeding artery diameter, low number of coils, use of oversized coils, and proximal coil placement within the feeding artery are associated with reperfusion. Distal coil placement facilitates repeat embolization if reperfusion occurs.

Cost comparison of genetic and clinical screening in families with hereditary hemorrhagic telangiectasia.

Endoglin (ENG) and ALK-1 mutations cause hereditary hemorrhagic telangiecstasia (HHT), an autosomal dominant disorder leading to vascular dysplasia in the form of mucocutaneous telangiectasia and visceral arteriovenous malformations (AVMs). We proposed to compare two alternative strategies for management of HHT: screening HHT families with molecular diagnostic tests followed by targeted clinical screening versus conventional clinical screening. A decision analytic model was constructed to compare screening strategies for a hypothetical HHT family. The family consists of 1 index case and 13 relatives. The clinical screening protocol in use at the Canadian HHT Center in Toronto was assumed to be the standard of care. Unit costs for clinical screening (in Canadian dollars) were obtained from the 2003 Ontario Health Insurance Schedule of Benefits. Genetic screening costs were estimated for quantitative multiplex PCR and sequencing of Endoglin (ENG) and ALK-1 genes, as performed at HHT Solutions, Toronto. The genetic screening strategy resulted in a net cost of $4,060 per individual versus $5,975 for the clinical screening strategy. The genetic screening strategy would save $1,915 per family member or $26,810 saved per family. Sensitivity analyses revealed that the genetic screening strategy was cost saving over all plausible ranges of input variables for all hypothetical families tested. We concluded that a genetic screening strategy with targeted clinical screening is more economically attractive than conventional clinical screening and results in a reduction in the number of clinical tests for family members who do not have HHT.

Age-related normal ranges for the Haller index in children.

PURPOSE: The Haller index is an accepted CT method for evaluating thoracic dimensions in patients with pectus excavatum. The purpose of this study is to establish age- and gender-related norms for the Haller index in childhood. MATERIALS AND METHODS: We retrospectively reviewed 574 consecutive chest CT examinations (M=285, F=289) performed at our institution from August 2001 through March 2002. Seventeen patients with a history of chest-wall deformity, trauma, or syndrome were excluded, for a total sample size of 557 patients. The Haller index was calculated for each patient, using electronic calipers. The sample population was then separated by gender and placed into 2-year age groupings. Two-way analysis of variance and Tukey's multiple comparisons were performed to determine significance at a=0.05. The least-square mean Haller index values for each age group and gender were calculated with 95% confidence intervals. RESULTS: In both males and females, the 0- to 2-year age group showed a significantly smaller mean Haller index than older children. In addition, females had significantly greater Haller index values than males in the 0- to 6- and 12- to 18-year age groups. CONCLUSION: The Haller index, a quantitative measurement of chest-wall configuration, demonstrates significant age- and gender-related variability. This should be considered when evaluating the patient with suspected chest-wall deformity.