Screening for pulmonary arteriovenous malformations using transthoracic contrast echocardiography: a prospective study

Pulmonary arteriovenous malformations in patients with previous brain abscess: a cross-sectional population-based study

BACKGROUND AND PURPOSE

Pulmonary arteriovenous malformations (PAVMs) may cause recurrent brain abscess. The primary aim was to determine the prevalence of PAVM amongst survivors of brain abscess. The proportion with cardiac right-to-left shunts was also assessed post hoc.

METHODS

This was a cross-sectional population-based study of adult (≥18 years) survivors of cryptogenic bacterial brain abscess in Denmark from 2007 through 2016. Patients were invited for bubble-echocardiography to detect vascular right-to-left shunting and, if abnormal, subsequent computed tomography thorax for diagnosis of PAVM. Data are presented as n/N (%) or median with interquartile range (IQR).

RESULTS

Study participation was accepted by 47/157 (30%) eligible patients amongst whom two did not appear for scheduled bubble-echocardiography. The median age of participants was 54 years (IQR 45-62) and 19/57 (33%) were females compared with 59 years (IQR 48-68, p = 0.05) and 41/85 females (48%, p = 0.22) in non-participants. Bubble-echocardiography was suggestive of shunt in 10/45 (22%) participants and PAVM was subsequently confirmed by computed tomography in one patient with grade 1 shunting. The corresponding prevalence of PAVM was 2% (95% confidence interval 0.06-11.8) amongst all examined participants. Another 9/45 (20%) were diagnosed with patent in persistent foramen ovale (n = 8) or atrial septum defect (n = 1), which is comparable with the overall prevalence of 25% amongst adults in the Danish background population.

CONCLUSIONS

Undiagnosed PAVM amongst adult survivors of cryptogenic bacterial brain abscess is rare but may be considered in select patients. The prevalence of cardiac right-to-left shunts amongst brain abscess patients corresponds to the prevalence in the general population.

Cine MRI in the Evaluation of Pulmonary Arteriovenous Malformations

We present findings on cine magnetic resonance imaging (MRI) using steady-state free precession (SSFP) pulse sequences in a patient with pulmonary arteriovenous malformation (PAVM). The technique has the advantage of demonstrating the pulsation of lesions during the cardiac cycle on cine images. It may not replace but may complement other MRI sequences in the characterization of pulmonary lesions in selected cases. To our knowledge, no prior video of cine images of PAVM has been provided in the literature.

[Hereditary hemorrhagic telangiectasia]

Hereditary hemorrhagic telangiectasia, also known as Rendu-Osler - Weber disease, is a rare, autosomal dominant vascular disease, with prevalence of 1/5,000. The condition is characterized by muco-cutaneous telangiectasias, which are responsible for a hemorrhagic syndrome of variable severity, as well as arteriovenous malformations (AVMs) appearing in the lungs, the liver, and the nervous system. They can be the source of shunts, which may be associated with high morbidity (neurological ischemic stroke, brain abscess, high-output heart failure, biliary ischemia…). It is therefore crucial to establish a clinical diagnosis using the Curaçao criteria or molecular diagnosis based on genetic analysis of the ENG, ACVRL1, SMAD4 and GDF2 genes. In most cases, multidisciplinary management allows patients to have normal life expectancy. Advances in interventional radiology and better understanding of the pathophysiology of angiogenesis have resulted in improved therapeutic management. Anti-angiogenic treatments, such as bevacizumab (BVZ, an anti-VEGF antibody), have proven to be effective in cases involving bleeding complications and severe liver damage with cardiac repercussions. Other anti-angiogenic agents are currently being investigated, including tyrosine kinase inhibitors.

Evolution of Pulmonary Arteriovenous Malformations: The Role of Contrast Echocardiography

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) are direct connections between the pulmonary artery and the pulmonary vein, mostly associated with hereditary hemorrhagic telangiectasia (HHT). PAVMs can lead to severe neurologic complications such as stroke and brain abscess. The risk of complications decreases after embolization. Therefore, screening for PAVMs using transthoracic contrast echocardiography (TTCE) is recommended, including a rescreening interval of 5 years.

RESEARCH QUESTION

Is extension of the interval for rescreening patients without a pulmonary right-to-left shunt (RLS) of up to 10 years appropriate?

STUDY DESIGN AND METHODS

Adult patients with HHT with 5- or 10-year follow-up TTCE, or both, were included. Patients who underwent PAVM embolization in the past or at baseline were excluded. The RLS grades and presence of a treatable PAVM were compared with baseline.

RESULTS

In total, 387 patients (median age, 45 years [interquartile range, 33-54 years]; 56% women) involving 5- and 10-year follow-up data in 363 and 166 patients, respectively, were included. None of the patients (n = 148) without a pulmonary RLS at baseline demonstrated a treatable PAVM after 5 and 10 years. Of the patients with a pulmonary RLS at baseline, 20 patients (9%) and three patients (3%) demonstrated a treatable PAVM at the 5- and 10-year follow-up, respectively. In most patients, the RLS grade remained stable over time.

INTERPRETATION

On the basis of the results of this retrospective study, we believe that the rescreening interval for patients with HHT without a pulmonary RLS at initial screening may be extended to 10 years. Those with a pulmonary RLS should be rescreened every 5 years because treatable PAVMs can evolve.

Significance of transesophageal contrast echocardiography with the agitated saline test for diagnosing pulmonary arteriovenous malformations

Objectives

This study evaluated the diagnostic value of transesophageal contrast echocardiography (TECE) with the agitated saline test for diagnosing pulmonary arteriovenous malformations (PAVMs) in comparison with chest CT or pulmonary angiography.

Background

Although transthoracic contrast echocardiography (TTCE) is the recommended screening test for diagnosing PAVMs, it has low specificity and positive predictive value. TECE is expected to offer improved sensitivity and specificity compared with TTCE, but no studies have reported the diagnostic accuracy and clinical significance of TECE in detecting PAVMs.

Methods and results

In total, 1,809 patients underwent TECE with the agitated saline test to evaluate symptoms of a suspected right to left shunt. Patients with hereditary hemorrhagic telangiectasia (HHT) were excluded. A total of 387 patients showed transpulmonary bubble passage, indicating a PAVM. Among them, 182 patients had additional chest CT or pulmonary angiography. Those patients were divided into two groups according to the presence of a PAVM in the radiologic imaging. A total of 18 patients (9.8%) were confirmed for the PAVM group. Only 13 patients required embolization for their PAVMs. The TECE with saline test results were divided into four grades according to the number of bubbles: grade 1 (n = 91), grade 2 (n = 47), grade 3 (n = 35), and grade 4 (n = 9). None of the patients in the PAVM group had grade 1 shunts in their TECE results. The positive predictive values for the presence of a PAVM according to the TECE grade scale were 10.6% for grade 2, 22.8% for grade 3, and 55.6% for grade 4.

Conclusion

TECE with a grade scale is a useful method for initially diagnosing PAVMs in non-HHT patients with a suspected right to left shunt. The findings of this study also suggest that patients with a small grade (<10 bubbles) shunt in their TECE findings should be spared unnecessary radiation exposure from CT scans or pulmonary angiography.

Hereditary Hemorrhagic Telangiectasia: Genetics, Pathophysiology, Diagnosis, and Management

Hereditary hemorrhagic telangiectasia is an inherited disease related to an alteration in angiogenesis, manifesting as cutaneous telangiectasias and epistaxis. As complications, it presents vascular malformations in organs such as the lung, liver, digestive tract, and brain. Currently, diagnosis can be made using the Curaçao criteria or by identifying the affected gene. In recent years, there has been an advance in the understanding of the pathophysiology of the disease, which has allowed the use of new therapeutic strategies to improve the quality of life of patients. This article reviews some of the main and most current evidence on the pathophysiology, clinical manifestations, diagnostic approach, screening for complications, and therapeutic options, both pharmacological and surgical.

Diagnosis of left anterior descending branch-right ventricular fistula with giant coronary artery aneurysm by contrast echocardiography: A case report

BACKGROUND

Coronary fistulae are communications between a coronary artery and a heart chamber or vessel. The final diagnosis is usually made by coronary angiography or computed tomographic (CT) angiography. Here we report a case by employing contrast echocardiography in diagnosis of a giant coronary aneurysm with right ventricle (RV) fistula.

CASE PRESENTATION

The patient, a 29-year-old woman, referred to our institution with a complaint of palpitation occasionally. Transthoracic echocardiogram showed a spherical, echogenic structure in the apex of RV. Proximal to the aneurysm, the left anterior descending branch (LAD) remained enlarged (8-9 mm) and showed a fistulous communication with the echogenic structure. A contrast echocardiography was performed, and 4-5 cardiac cycle after the left ventricle was enhanced, the echogenic structure started to become more prominent and several fistulae were seen between RV and the echogenic structure. Computed tomography (CT) angiography and coronary angiography confirmed the dilation (9 mm in diameter) of the LAD with an aneurysm at the distal segment of the LAD, with a small amount of iodinated contrast agent flowing into the subsequent region of the RV, thereby characterizing a LAD-to-RV fistula.

CONCLUSION

The final diagnosis of fistula is usually made by coronary angiography or CT angiography. However, contrast echocardiography is also a well-established method for the demonstration of intracardiac shunting. In this case, the contrast echocardiography clearly revealed one of the fistulae between the aneurysm and RV.

CT Appearance of Pulmonary Arteriovenous Malformations and Mimics

A pulmonary arteriovenous malformation (PAVM) is a fistulous connection between a pulmonary artery and a pulmonary vein that bypasses the normal pulmonary capillary bed resulting in a right-to-left shunt. Because of the potential for paradoxical emboli, PAVMs are treated when their feeding arteries exceed 3 mm or patients are symptomatic. PAVMs are often encountered in patients with suspected hereditary hemorrhagic telangiectasia (HHT). Sporadic cases are uncommon. The radiologist may be called on to diagnose a PAVM after positive transthoracic contrast-enhanced echocardiography in a patient with suspected HHT to direct patient management and avoid potential complications. The radiologist may also be required to evaluate a potential PAVM detected at CT performed for other reasons. Through the authors' experiences at an HHT Center of Excellence in an area endemic with histoplasmosis, the authors have gained a unique perspective on the diagnosis of PAVMs and differentiation of PAVMs from their mimics. Understanding the CT appearance of PAVMs limits misdiagnosis, directs appropriate treatment, and allows subsequent family screening for HHT (and avoidance of unnecessary screening when a PAVM mimic is encountered). Both vascular and nonvascular pulmonary lesions can mimic PAVMs. Vascular mimics include fibrosing mediastinitis, venovenous collaterals, arterial collaterals, pulmonary artery pseudoaneurysms, hepatopulmonary vessels, Sheehan vessels, meandering pulmonary veins, and pulmonary vein varices. Nonvascular mimics include granulomas, nodules, mucoceles, bronchoceles, ground-glass opacities, and atelectasis. The authors review the CT technique for evaluating PAVMs and the appearance of PAVMs and their mimics. ^©RSNA, 2022.

The use of echo density to quantify pulmonary right-to-left shunt in transthoracic contrast echocardiography

AIMS

Transthoracic contrast echocardiography (TTCE) is the recommended screening tool to detect pulmonary right-to-left shunt (RLS) caused by pulmonary arteriovenous malformations (PAVMs). We assessed a novel method to quantify the RLS using the change in echo density (ED) following contrast injection.

METHODS AND RESULTS

An analysis of 437 consecutive patients [58% female, 47 years, interquartile range (IQR) 33-60] who underwent TTCE for the detection of a pulmonary RLS. Using ImageJ (National Institutes of Health), the change in ED was measured for each patient. This method was strongly correlated (Spearman's ρ = 0.89; P < 0.0001) with our standard method based on a four-point grading scale (no, mild, moderate, and severe RLS). In patients without a history of embolotherapy (n = 334), a PAVM was detected with chest computed tomography (CT) in 66 and embolotherapy was judged possible in 35 of these patients. The median increase in ED was higher in the latter: +20.1% (IQR 12.3-34.0) compared to non-treatable PAVM +0.2% (IQR -0.2 to 1.1). The specificity to detect treatable PAVMs increased from 87% to 90% when using the novel method without affecting the sensitivity (of 100%). Using the optimal cut-off value of +4.5% increase in ED, 8/74 (11%) needed chest CT-scans-individuals with a moderate or severe RLS-were no longer required without missing any treatable PAVM.

CONCLUSIONS

The use of ED quantification for pulmonary RLS is promising; resulting in a substantial decrease in the number of chest CT scans needed. However, this method and the threshold should be validated in an independent study population.

Reliable Detection of Intrapulmonary Shunts Using Contrast-Enhanced Echocardiography in Children With Portal Hypertension or Portosystemic Shunt

OBJECTIVES

The aim of this study was to analyze if contrast-enhanced echocardiography (CEE) is as reliable as lung perfusion scintigraphy (LPS) to detect intrapulmonary shunting (IPS) in children with portal hypertension (PHTN) or congenital/surgical portosystemic shunts (PSS) and to define the number of cardiac cycles required to exclude intrapulmonary shunting.

METHODS

Inclusion criteria for this cross-sectional study were: (1) presence of PHTN or PSS diagnosed on abdominal ultrasound, (2) technically valid saline contrast echocardiography, (3) lung perfusion scintigraphy within 6 months of CEE. The number of cardiac cycles between right atrial opacification and the arrival of contrast in the left atrium were counted. We analyzed our CEE data at three and five cardiac cycles and compared them with LPS results.

RESULTS

The study population was composed of 78 children (38 girls, 49%) ages 2.1-18.8 years (mean 9.8). Sixty-nine patients had PHTN (88%), and nine had a PSS (11%). Eleven subjects (14%) presented evidence of IPS on LPS. Peripheral oxygen saturation was lower in the subjects with IPS detected on LPS (95.3 ± 1.7% vs 99.0 ± 1.4%; P < 0.01). Comparison of LPS with CEE before three and five cardiac cycles showed that CEE is highly specific (95.7%) as early as three cardiac cycles with markedly better sensitivity (72.7%) when using five cardiac cycles. Furthermore, a negative study using five cardiac cycles ruled out IPS with a 95% negative predictive value. The cardiac cycle at which the bubbles appeared in the left atrium was inversely correlated to the shunt index measured using LPS (r = -0.563; P = 0.001).

CONCLUSION

CEE is sufficient for the screening of IPS in children with PHTN or congenital/surgical PSS, obviating the need for LPS.

Idiopathic and hereditary haemorrhagic telangiectasia associated pulmonary arteriovenous malformations: comparison of clinical and radiographic characteristics

AIM

To determine whether there are differences between idiopathic and hereditary haemorrhagic telangiectasia (HHT) associated pulmonary arteriovenous malformations (PAVMs) (HHT-PAVM) regarding clinical and radiographic characteristics, and the results of embolotherapy.

MATERIALS AND METHODS

A retrospective analysis was undertaken of all adult and adolescent patients who were diagnosed with a PAVM on chest computed tomography (CT) from January 2006 until August 2019.

RESULTS

In total, 41 patients with idiopathic PAVMs and 194 patients with genetically confirmed HHT and PAVMs were included. Idiopathic PAVMs were more frequently observed in female patients, were more solitary, and predominantly located in the lower lobes. The diameter of the feeding artery and type of PAVM (simple versus complex) were similar. Embolotherapy results were comparable between both groups with similar re-embolisation rates.

CONCLUSIONS

PAVMs of idiopathic origin are predominantly found in women, more frequently located in the lower lobes, and solitary compared to HHT-PAVMs; however, the outcome of treatment is the same, suggesting that treatment and follow-up should be similar in both groups.

Echocardiographic diagnosis of right-to-left shunt using transoesophageal and transthoracic echocardiography

Background

The diagnosis and quantification of right-to-left shunt (RLS) using transthoracic echocardiography (TTE) as well as transoesophageal echocardiography (TOE) have not been well established. We aimed to diagnose RLS by TOE using direct visualisation of the shunt and to compare the diagnosis with TTE diagnosis using conventional methods.

Methods and results

We evaluated 141 patients with ischaemic stroke for RLS by both non-sedation TOE and TTE using saline contrast and Valsalva manoeuvre. The amount (graded as 0 to IV) and timing of RLS were demonstrated. All patients were classified into four groups by TOE based on direct visualisation of shunt through a patent foramen ovale (PFO) or either pulmonary vein: no shunt (group 1: n=11), PFO (group 2: n=47), pulmonary RLS (group 3: n=25) and indeterminate RLS (group 4: n=58). All cases in group 3 showed delayed shunt, and all cases in group 4 had small shunt. On TTE findings, all cases with early appearing large shunt (cardiac cycles ≤3 and shunt grade ≥III) were group 2. Six of the eight patients with delayed appearing large shunt on TTE were group 3. TTE diagnosis of PFO using criteria of cardiac beats ≤3 and grade ≥II had a sensitivity of 85% and a specificity of 98% compared with TOE diagnosis using shunt visualisation.

Conclusions

Compared with TOE using shunt visualisation, TTE accurately diagnosed large PFO using criteria of cardiac cycles ≤3 and shunt grade ≥III. TTE possibly diagnosed pulmonary shunt using criteria of cardiac cycles >3 and shunt grade ≥III. Both modalities showed limitations in diagnosing small amount of RLS.

Hereditary Hemorrhagic Telangiectasia (HHT) and Survival: The Importance of Systematic Screening and Treatment in HHT Centers of Excellence

Hereditary hemorrhagic telangiectasia (HHT), an autosomal dominant disease, is characterized by telangiectases and arteriovenous malformations (AVMs). Untreated AVMs, especially in the lungs—pulmonary AVMs (PAVMs)—can result in morbidity with a decreased life expectancy. We have investigated whether HHT patients, systematically screened for HHT-related organ involvement and treated if needed, have a similar survival as persons without HHT. We included all individuals screened for HHT between 2004 and 2016 with a genetically or clinically confirmed diagnosis (HHT group) or excluded diagnosis (non-HHT control group). The social security number was used to confirm status as dead or alive in December 2019. We included 717 HHT patients and 471 controls. There was no difference in survival between the HHT and the non-HHT control group. The HHT group had a life expectancy of 75.9 years (95% confidence interval (CI) 73.3–78.6), comparable to the control group (79.3 years, 95% CI 74.8–84.0, Mantel–Cox test: p = 0.29). In conclusion, the life expectancy of HHT patients systematically screened for HHT-related organ involvement and treated if needed in an HHT center of excellence was similar compared to their controls, justifying systematic screening and treatment in HHT patients.

Diagnosing pulmonary arteriovenous malformations in the presence of atrial septal defect and anomalous pulmonary venous drainage-An imaging challenge

Saline contrast echocardiography is a simple and effective method to diagnose the presence and type of right-to-left shunt in patients with unexplained cyanosis. It is considered a very sensitive test to diagnose pulmonary arteriovenous malformations. Our patient presented with unexplained cyanosis and transthoracic echocardiography showed an atrial septal defect and anomalous pulmonary venous drainage of the right and left upper pulmonary veins to the superior venacava. We describe how we used saline contrast echocardiography to demonstrate the presence of pulmonary arteriovenous malformations even in the presence of atrial septal defect and anomalous pulmonary venous drainage.

Postembolotherapy Pulmonary Arteriovenous Malformation Follow-Up: A Role for Graded Transthoracic Contrast Echocardiography Prior to High-Resolution Chest CT Scan

BACKGROUND

High-resolution chest CT (HRCT) scan is recommended after pulmonary arteriovenous malformation (PAVM) embolotherapy to assess for PAVM persistence and untreated PAVM growth. Graded transthoracic contrast echocardiography (TTCE) predicts the need for embolotherapy in PAVM screening. This study sought to determine whether postembolotherapy graded TTCE can similarly predict the need for repeat embolotherapy.

METHODS

Thirty-two patients (8 men and 24 women; mean age, 51.1 ± 12.6 years) with prior PAVM embolotherapy and follow-up HRCT scan were prospectively enrolled. Patients underwent graded TTCE using a validated three-point quantitative grading scale. TTCE grade and HRCT findings were compared.

RESULTS

Median time between most recent HRCT scan and TTCE was 7 days (interquartile range, 0-272 days). Thirty patients (94%) had no PAVMs requiring repeat embolotherapy on HRCT scan. Two patients (6%) had PAVMs requiring repeat embolotherapy (feeding artery [FA] ≥ 3 mm), one with untreated PAVM growth and one with treated PAVM persistence. TTCE was positive in 88% of patients (n = 28). All patients (n = 4, 12%) with negative TTCE had no visible PAVMs on HRCT scan. Nine patients (32%) had grade 1 shunt, 10 (35%) had grade 2 shunt, and nine (32%) had grade 3 shunt. No patients with grade 1 shunt had PAVMs amenable to repeat embolotherapy on HRCT scan. All patients (n = 2) with PAVMs requiring repeat embolotherapy (FA ≥ 3 mm) had grade 3 shunt. TTCE grade was significantly associated with PAVM FA diameter (P < .001).

CONCLUSIONS

Postembolotherapy graded TTCE can predict the need for repeat embolotherapy on HRCT scan. Patients with negative TTCE and grade 1 shunt may not require HRCT follow-up and can potentially be followed with serial graded TTCE.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02936349; URL: www.clinicaltrials.gov.

Saline Contrast Transesophageal Echocardiography in Fontan Patients: Assessment of the Presence, Type, and Size of Right to Left Shunts

Right to left (R-L) shunts resulting in cyanosis or systemic embolization occur after the Fontan procedure. The primary modality of diagnosing these is angiography. Successful delineation of these shunts in Fontan patients using selective saline contrast transesophageal echocardiography (SCTEE) may allow for reduced radiation and contrast exposure. We hypothesized that SCTEE could accurately determine the presence, type, and semiquantitative shunt size of R-L shunts in Fontan patients. SCTEE was performed in Fontan patients undergoing angiography for clinical indications. Injections were performed in six sites: mid-Fontan, right and left pulmonary arteries, superior and inferior vena cavae, and innominate vein. R-L shunt size was subjectively graded as 0 = absent, 1 = small, and 2 = medium or large based on echo contrast density in the left atrium. SCTEE was compared to angiography. 33 patients with Fontan were studied with median age 15 years, median weight 50.1 kg, and median O₂ saturation of 90% in the R-L shunt group and 95% in the no R-L shunt group. R-L shunt types included intracardiac shunts (ICS), veno-venous collaterals (VVCs), arteriovenous malformations (AVMs), and their combinations. SCTEE versus angiography results were the same for the presence, type, and size of R-L shunts in 79% (26/33). SCTEE identified shunts in 88% (29/33). Angiography identified shunts in 85% (28/33). Neither method missed any medium or large R-L shunts. SCTEE and angiography had similar accuracy. SCTEE accurately detected the presence, type, and size of R-L shunts in most Fontan patients in this study. This can be used to guide targeted angiography, reducing radiation exposure and contrast load.

Lack of Growth of Small (≤2 mm Feeding Artery) Untreated Pulmonary Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia

PURPOSE

To assess pulmonary arteriovenous malformation (PAVM) growth among patients with untreated PAVMs using imaging from long-term follow-up per hereditary hemorrhagic telangiectasia international guidelines.

MATERIALS AND METHODS

Analysis included 88 untreated PAVMs from 21 patients (6 male;15 female; mean age at presentation 47 y; range, 12-68 y). Two CT studies with the longest interval between were evaluated (mean 8.4 y; median 8.8 y; range, 3.1-14.1 y). Measurement of feeding artery diameter and anteroposterior (AP) and mediolateral (ML) sac dimensions for each PAVM was performed separately by 2 radiologists blinded to patient and CT order. Statistical analysis was performed to determine change in size between earliest and follow-up imaging.

RESULTS

Mean feeding artery diameter, AP sac dimension, and ML sac dimension were 1.4 mm (range, 0.8-3.7 mm), 4.3 mm (range, 2.1-11.1 mm), and 4.1 mm (range, 1.8-9.2 mm) on earliest imaging and 1.4 mm (range, 0.9-2.6 mm), 4.5 mm (range, 2.2-12.2 mm), and 4.3 mm (range, 2.0-9.6 mm) on follow-up. Model-based mean analysis showed no statistically significant change in dimension of any variable between earliest and follow-up imaging. Secondary analysis including age also found no statistically significant difference (feeding diameter, P = .09; AP sac dimension, P = .9; ML sac dimension, P = .1). Analysis including time between measurements found no significant relationship between change in variables and time (feeding artery diameter, P = .4; AP sac dimension, P = .3; ML sac dimension, P = .06).

CONCLUSIONS

Untreated PAVMs grew slowly, if at all, in a near-decade span, and any demonstrated growth was minimal. These findings challenge the current recommendation of 3- to 5-year CT follow-up.

Systematic screening in hereditary hemorrhagic telangiectasia: a review

PURPOSE OF REVIEW

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant inherited disease characterized by telangiectasia and arteriovenous malformations (AVMs). To date, five genetic types of HHT and one combined juvenile polyposis syndrome and HHT are known. Clinical and genetic screening of patients suspected with HHT is recommended to confirm the diagnosis and to prevent complications associated with HHT. The aim of this article is to give an overview of the evidence and to formulate a recommendation for clinicians concerning screening for HHT.

RECENT FINDINGS

Complications of HHT such as stroke, brain abscess and intracranial hemorrhage are caused by pulmonary and cerebral AVMs (CAVMs) and can often be prevented by screening and treatment when possible. Screening and treatment of these AVMs will result in an increased life expectancy comparable with that of the general population as opposed to unscreened and untreated HHT patients.

SUMMARY

Screening of HHT patients and their first-degree relatives is recommended to prevent severe complications including stroke, brain abscess and intracranial hemorrhage.

Applicability of the Curaçao Criteria for the Diagnosis of Hereditary Hemorrhagic Telangiectasia in the Pediatric Population

OBJECTIVE

To evaluate the accuracy of the clinical Curaçao criteria in the diagnosis of hereditary hemorrhagic telangiectasia (HHT) in children and adolescents.

STUDY DESIGN

This was a retrospective, multicenter chart review of 673 patients evaluated between 2002 and 2016; 290 were eligible for the study. Genetic testing for a pathogenic mutation was considered the gold standard against which the clinical Curaçao criteria were compared. Patients were divided into 4 age categories: 0-5, 6-10, 11-15, and 16-21-years. Sensitivity and specificity were calculated for each age group, and for the overall population.

RESULTS

Overall the Curaçao criteria had a sensitivity of 68% (95% CI 60%-76%) and a specificity of 98% (95% CI 91%-100%). Sensitivity was lowest in the 0- to 5-year group, and increased with advancing age. The Curaçao criteria had the highest sensitivity in the 16- to 21-year-olds. Specificity was 100% in all age groups except for the 11- to 15-year-olds.

CONCLUSIONS

This study evaluated the use of the Curaçao criteria for the diagnosis of HHT in the pediatric population with a family history of HHT. In those between the age of 0 and 21 years who meet 1 criterion (unlikely HHT) or 2 criteria (possible HHT), genetic testing is preferred for diagnosis. The Curaçao criteria appear to reliably diagnose HHT in children and adolescents who meet 3 or 4 criteria (definite HHT).

Echocardiography Grading for Pulmonary Arteriovenous Malformation Screening in Children with Hereditary Hemorrhagic Telangiectasia

Transthoracic contrast echocardiography (TTCE) has high sensitivity but low specificity in screening for pulmonary arteriovenous malformations (pAVMs) in children with hereditary hemorrhagic telangiectasia (HHT). Here we describe characteristics of TTCE that might be used to reduce the need for confirmatory computed tomography scans in children with HHT.

Reproducibility of right-to-left shunt quantification using transthoracic contrast echocardiography in hereditary haemorrhagic telangiectasia

Aim

Transthoracic contrast echocardiography (TTCE) is recommended for screening of pulmonary arteriovenous malformations (PAVMs) in hereditary haemorrhagic telangiectasia. Shunt quantification is used to find treatable PAVMs. So far, there has been no study investigating the reproducibility of this diagnostic test. Therefore, this study aimed to describe inter-observer and inter-injection variability of TTCE.

Methods

We conducted a prospective single centre study. We included all consecutive persons screened for presence of PAVMs in association with hereditary haemorrhagic telangiectasia in 2015. The videos of two contrast injections per patient were divided and reviewed by two cardiologists blinded for patient data. Pulmonary right-to-left shunts were graded using a three-grade scale. Inter-observer and inter-injection agreement was calculated with κ statistics for the presence and grade of pulmonary right-to-left shunts.

Results

We included 107 persons (accounting for 214 injections) (49.5% male, mean age 45.0 ± 16.6 years). A pulmonary right-to-left shunt was present in 136 (63.6%) and 131 (61.2%) injections for observer 1 and 2, respectively. Inter-injection agreement for the presence of pulmonary right-to-left shunts was 0.96 (95% confidence interval (CI) 0.9–1.0) and 0.98 (95% CI 0.94–1.00) for observer 1 and 2, respectively. Inter-injection agreement for pulmonary right-to-left shunt grade was 0.96 (95% CI 0.93–0.99) and 0.95 (95% CI 0.92–0.98) respectively. There was disagreement in right-to-left shunt grade between the contrast injections in 11 patients (10.3%). Inter-observer variability for presence and grade of the pulmonary right-to-left shunt was 0.95 (95% CI 0.91–0.99) and 0.97 (95% CI 0.95–0.99) respectively.

Conclusion

TTCE has an excellent inter-injection and inter-observer agreement for both the presence and grade of pulmonary right-to-left shunts.

Electronic supplementary material

The online version of this article (10.1007/s12471-018-1094-4) contains supplementary material, which is available to authorized users.

99mTc-MAA Pulmonary Scintigraphy in Hereditary Hemorrhagic Telangiectasia

A 5-year-old boy was admitted due to shortness of breath. Blood gas analysis showed hypoxemia. However, thoracic and abdominal CT, brain MRI, and MR angiography were all normal. A Tc-MAA pulmonary scintigraphy revealed right-to-left shunting of the blood. Further genetic analysis showed the mutations in the activin receptor-like kinase 1 gene, and a diagnosis of hereditary hemorrhagic telangiectasia was made.

Follow-up of pulmonary right-to-left shunt in hereditary haemorrhagic telangiectasia

Pulmonary arteriovenous malformations (PAVMs) are associated with severe neurological complications in hereditary haemorrhagic telangiectasia (HHT). Transthoracic contrast echocardiography (TTCE) is recommended for screening of pulmonary right-to-left shunts (RLS). Although growth of PAVMs is shown in two small studies, no studies on follow-up with TTCE exist.All HHT patients underwent a second TTCE 5 years after initial screening. Patients with a history of PAVM embolisation were excluded. Pulmonary RLS grade on TTCE after 5 years was compared to the grade at screening.200 patients (53.5% female, mean±sd age at screening 44.7±14.1 years) were included. Increase in RLS grade occurred in 36 (18%) patients, of whom six (17%) underwent embolisation. The change in grade between screening and follow-up was not more than one grade. Of patients with nontreatable pulmonary RLS at screening (n=113), 14 (12.4%) underwent embolisation. In patients without pulmonary RLS at initial screening (n=87), no treatable PAVMs developed during follow-up.Within 5 years, no treatable PAVMs developed in HHT patients without pulmonary RLS at initial screening. Increase in pulmonary RLS grade occurred in 18% of patients, and never increased by more than one grade. Of patients with nontreatable pulmonary RLS at initial screening, 12% underwent embolisation.

ACR Appropriateness Criteria Clinically Suspected Pulmonary Arteriovenous Malformation

Pulmonary arteriovenous malformations are often included in the differential diagnosis of common clinical presentations, including hypoxemia, hemoptysis, brain abscesses, and paradoxical stroke, as well as affecting 30% to 50% of patients with hereditary hemorrhagic telangiectasia (HHT). Various imaging studies are used in the diagnostic and screening settings, which have been reviewed by the ACR Appropriateness Criteria Vascular Imaging Panel. Pulmonary arteriovenous malformation screening in patients with HHT is commonly performed with transthoracic echocardiographic bubble study, followed by CT for positive cases. Although transthoracic echocardiographic bubble studies and radionuclide perfusion detect right-to-left shunts, they do not provide all of the information needed for treatment planning and may remain positive after embolization. Pulmonary angiography is appropriate for preintervention planning but not as an initial test. MR angiography has a potential role in younger patients with HHT who may require lifelong surveillance, despite lower spatial resolution compared with CT. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Pulmonary Arteriovenous Malformations and Risk of Stroke

Pulmonary arteriovenous malformations (PAVMs) are rare, with an estimated incidence of 2 to 3 cases per 100,000, with most PAVMs (50%-80%) occurring in patients with hereditary hemorrhagic telangiectasia. Hypoxemia and orthodeoxia are some of the more common clinical presentations. The estimated risk of stroke secondary to PAVMs is as high as 2.6% to 25.0%. A combination of chest radiograph and contrast echocardiography is a good screening evaluation in patients with suspected PAVMs. Transcatheter therapy is the most suitable therapeutic option in most patients with PAVMs, and a variety of devices can be used to occlude the PAVMs.

Pulmonary arteriovenous malformation-etiology, clinical four case presentations and review of the literature

Pulmonary arteriovenous malformation (PAVM) is a rare clinical condition with abnormal direct communication between the branches of pulmonary artery and vein. It may occur as an isolated anomaly or in association with hereditary hemorrhagic telangiectasia (HHT). Although these vascular pulmonary pathologies are quite uncommon, they are the important part of the differential diagnosis of common pulmonary problems such as hypoxemia and pulmonary nodules. The diagnosis of PAVM in patients remains a diagnostic challenge to the emergency physician. The most common clinical signs of PAVM are recurrent episodes of epistaxis and hemoptysis, so surgical resection is deemed the best curative option to avoid further episodes and recurrence of hemoptysis. Quite often the diagnosis is established after pathohistological examinations. We report a case of a female patient with a massive recurrent hemoptysis and without pathologic radiological findings which would suggest to PAVM and who was successfully treated with lobectomy.

Saline Contrast Echocardiography in the Era of Multimodality Imaging--Importance of "Bubbling It Right"

Saline contrast echocardiography is an established imaging modality. Logical interpretation of a carefully performed study is vital to realize its diagnostic potential. In this review, we discuss utility of saline contrast echocardiography in evaluation of various pathologies within and outside the heart other than a patent foramen ovale.

Pulmonary hypertension in hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant inherited disorder characterised by vascular malformations in predominantly the brain, liver and lungs. Pulmonary hypertension (PH) is increasingly recognised as a severe complication of HHT. PH may be categorised into two distinct types in patients with HHT. Post-capillary PH most often results from a high pulmonary blood flow that accompanies the high cardiac output state associated with liver arteriovenous malformations. Less frequently, the HHT-related gene mutations in ENG or ACVRL1 appear to predispose patients with HHT to develop pre-capillary pulmonary arterial hypertension. Differentiation between both forms of PH by right heart catheterisation is essential, since both entities are associated with severe morbidity and mortality with different treatment options. Therefore all HHT patients should be referred to an HHT centre.

Carotid ultrasound for pulmonary arteriovenous malformation screening

OBJECTIVE

In patients with hereditary hemorrhagic telangiectasia (HHT), pulmonary arteriovenous malformations (PAVMs) can cause serious neurological complications. Our aim was to evaluate the potential of contrast-enhanced Doppler ultrasound (CE-US) of the common carotid artery as a screening test for detection of PAVMs.

METHODS

A total of 124 consecutive patients with HHT or a positive family history underwent screening for PAVMs with CE-US and thoracic contrast-enhanced magnetic resonance angiography (CE-MRA). CE-US was performed after receiving (D)-galactose microparticulate, and CE-MRA with gadobenate dimeglumine. Twenty-five patients with confirmed PAVMs were referred to conventional pulmonary catheter angiography (PA). Findings on CE-US and CE-MRA were evaluated using contingency tables and McNemar's test.

RESULTS

Using CE-MRA as the reference test, CE-US had a sensitivity of 100%, a specificity of 87%, and a negative predictive value of 100%. In 25 patients who underwent PA, PAVMs that had been diagnosed on CE-US and CE-MRA were confirmed. Of the PAVMs detected by CE-MRA, 24% were not identified on PA.

CONCLUSION

CE-US is a simple, minimally invasive screening method that can easily be performed in different settings. CE-US can predict PAVMs with high probability of success. CE-US may be a simple alternative to transthoracic echocardiography in the assessment of PAVMs in certain HHT-patients.

Percutaneous closure of secundum type atrial septal defects: More than 5-year follow-up

AIM: To investigate long-term efficacy of two different devices more than five years after percutaneous atrial septal defect (ASD) closure in adults.

METHODS: All patients who underwent percutaneous closure of an ASD in the St. Antonius Hospital, Nieuwegein, The Netherlands, between February 1998 and December 2006 were included. Percutaneous closure took place under general anaesthesia and transesophageal echocardiographic monitoring. Transthoracic echocardiography (TTE) was performed 24 h post-procedure to visualize the device position and to look for residual shunting using color Doppler. All complications were registered. All patients were invited for an outpatient visit and contrast TTE more than 5-years after closure. Efficacy was based on the presence of a residual right-to-left shunt (RLS), graded as minimal, moderate or severe. The presence of a residual left-to-right shunt (LRS) was diagnosed using color Doppler, and was not graded. Descriptive statistics were used for patients’ characteristics. Univariate analysis was used to identify predictors for residual shunting.

RESULTS: In total, 104 patients (mean age 45.5 ± 17.1 years) underwent percutaneous ASD closure using an Amplatzer device (ASO) in 76 patients and a Cardioseal/Starflex device (CS/SF) in 28 patients. The mean follow-up was 6.4 ± 3.4 years. Device migration occurred in 4 patients of whom two cases occurred during the index hospitalization (1 ASO, 1 CS/SF). The other 2 cases of device migration occurred during the first 6 mo of follow-up (2 CS/SF). The recurrent thrombo-embolic event rate was similar in both groups: 0.4% per follow-up year. More than 12 mo post-ASD closure and latest follow-up, new-onset supraventricular tachyarrhythmia’s occurred in 3.9% and 0% for the ASO and CS/SF group, respectively. The RLS rate at latest follow-up was 17.4% (minimal 10.9%, moderate 2.2%, severe 4.3%) and 45.5% (minimal 27.3%, moderate 18.2%, severe 0%) for the ASO- and CS/SF groups, respectively. There was no residual LRS in both groups.

CONCLUSION: Percutaneous ASD closure has good long-term safety and efficacy profiles. The residual RLS rate seems to be high more than 5 years after closure, especially in the CS/SF. Residual LRS was not observed.

Clinical implications of pulmonary shunting on saline contrast echocardiography

Pulmonary right-to-left shunting can be encountered using transthoracic contrast echocardiography (TTCE) with agitated saline. Diseases associated with pulmonary shunting on saline TTCE include hereditary hemorrhagic telangiectasia (HHT), hepatopulmonary syndrome, and some congenital heart defects after partial or complete cavopulmonary anastomosis. Furthermore, small pulmonary shunts on saline TTCE are also documented in a proportion of healthy individuals. Pulmonary shunting carries the risk for severe neurologic complications due to paradoxical embolization. In HHT, additional chest computed tomography is recommended in case of any pulmonary shunt detected on saline TTCE, to evaluate the feasibility for transcatheter embolotherapy of pulmonary arteriovenous malformations. Furthermore, antibiotic prophylaxis is advised in case of any pulmonary shunt on saline TTCE to prevent brain abscesses after procedures with risk for bacteremia. The present review provides an overview of important aspects of pulmonary shunting and its detection using saline TTCE. Furthermore, advances in understanding the clinical implications of different pulmonary shunt grades on saline TTCE are described. It appears that small pulmonary shunts on saline TTCE (grade 1) lack any clinical implication, as these shunts cannot be used as a diagnostic criterion for HHT, are not associated with an increased risk for neurologic complications, and represent pulmonary arteriovenous malformations too small for subsequent endovascular treatment. This implies that additional chest computed tomography could be safely withheld in all persons with only small pulmonary shunts on saline TTCE and sets the stage for further discussion about the need for antibiotic prophylaxis in these subjects. Besides further optimization of the current screening algorithm for the detection of pulmonary arteriovenous malformations in HHT, these observations can be of additional clinical importance in other diseases associated with pulmonary shunting and in those healthy individuals with documented small pulmonary shunts on saline TTCE.

Optimal management of hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT), also known by the eponym Osler-Weber-Rendu syndrome, is a group of related disorders inherited in an autosomal dominant fashion and characterized by the development of arteriovenous malformations (AVM) in the skin, mucous membranes, and/or internal organs such as brain, lungs, and liver. Its prevalence is currently estimated at one in 5,000 to 8,000. Most cases are due to mutations in the endoglin (HHT1) or ACVRLK1 (HHT2) genes. Telangiectasias in nasal and gastrointestinal mucosa generally present with recurrent/chronic bleeding and iron deficiency anemia. Larger AVMs occur in lungs (~40%-60% of affected individuals), liver (~40%-70%), brain (~10%), and spine (~1%). Due to the devastating and potentially fatal complications of some of these lesions (for example, strokes and brain abscesses with pulmonary AVMs), presymptomatic screening and treatment are of utmost importance. However, due to the rarity of this condition, many providers lack an appreciation for the whole gamut of its manifestations and complications, age-dependent penetrance, and marked intrafamilial variation. As a result, HHT remains frequently underdiagnosed and many families do not receive the appropriate screening and treatments. This article provides an overview of the clinical features of HHT, discusses the clinical and genetic diagnostic strategies, and presents an up-to-date review of literature and detailed considerations regarding screening for visceral AVMs, preventive modalities, and treatment options.

Direct haemodynamic effects of pulmonary arteriovenous malformation embolisation

BACKGROUND

Transcatheter embolisation is widely used to close pulmonary arteriovenous malformations (PAVMs) in patients with hereditary haemorrhagic telangiectasia (HHT). Data on the direct cardiovascular haemodynamic changes induced by this treatment are scarce.

OBJECTIVES

We investigated the direct haemodynamic effects of transcatheter embolisation of PAVMs, using non-invasive finger pressure measurements.

METHODS

During the procedure, blood pressure, heart rate (HR), stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR) and delta pressure/delta time (dP/dt) were continuously monitored using a Finometer®. Potential changes in these haemodynamic parameters were calculated from the pressure registrations using Modelflow® methodology. Absolute and relative changes were calculated and compared using the paired sample t-test.

RESULTS

The present study includes 29 HHT patients (mean age 39 ± 15 years, 11 men) who underwent transcatheter embolotherapy of PAVMs. The total number of embolisations was 72 (mean per patient 2.5). Directly after PAVM closure, SV and CO decreased significantly by -11.9 % (p = 0.01) and -9.5 % (p = 0.01) respectively, without a significant change in HR (1.8 %). Mean arterial blood pressure increased by 4.1 % (p = 0.02), while the TPR and dP/dt did not increase significantly (5.8 % and 0.2 %, respectively).

CONCLUSIONS

Significant haemodynamic changes occur directly after transcatheter embolisation of PAVMs, amongst which a decrease in stroke volume and cardiac output are most important.

Reliability of contrast echocardiography to rule out pulmonary arteriovenous malformations and avoid CT irradiation in pediatric patients with hereditary hemorrhagic telangiectasia

BACKGROUND

The overall risk of cancer is higher in people exposed to computed tomography (CT) scans in childhood or adolescence compared to adults. Transthoracic contrast echocardiography (TTCE) has recently been used to screen for pulmonary arteriovenous malformations (PAVMs) in children with hereditary hemorrhagic telangiectasia (HHT), but the value of TTCE to rule out PAVMs and avoid chest CT radiation has yet to be discussed.

METHODS

Between 2003 and 2013, 92 pediatric patients with ≥3 Curaçao criteria and/or genetic mutation underwent TTCE and chest CT on the same day. We used the classification proposed by Barzilai for TTCE quantification of shunting. We considered CT findings as negative when no PAVMs or only one microscopic PAVM was detected.

RESULTS

Mean age was 11.2 ± 4.1 years. The shunt was grade 0 on TTCE in 27.3%, grade 1 in 17%, grade 2 in 29.6%, grade 3 in 23.9%, and grade 4 in 2.2%. We found PAVMs on chest CT in 52.2%. All the patients with a grade 0 or 1 had a negative CT. The sensitivity and specificity of TTCE for the detection of PAVMs were 100% and 95.1%, respectively. The negative predictive value (NPV) was 100% and the positive predictive value (PPV) was 96%.

CONCLUSIONS

A low-grade classification (Barzilai 0 or 1) could presumably exclude the presence of PAVMs and allow CT irradiation to be avoided in children and adolescents. The screening algorithm using TTCE first would allow more than 40% of the pediatric patients screened for PAVMs to be spared the radiation dose of CT.

Grade of pulmonary right-to-left shunt on contrast echocardiography and cerebral complications: a striking association

BACKGROUND

A pulmonary right-to-left shunt (RLS) carries the risk of cerebral paradoxical embolization and severe neurologic complications. Recognizing patients at risk is important to facilitate appropriate management strategies, but a direct relation between pulmonary shunt size and risk of complications remains controversial. This study evaluated the potential relation between pulmonary shunt grade on transthoracic contrast echocardiography (TTCE) and prevalence of cerebral manifestations in patients screened for hereditary hemorrhagic telangiectasia (HHT).

METHODS

We conducted a two-center, cross-sectional study of all consecutive patients screened for HHT between 2004 and 2011. Pulmonary shunt grading on TTCE (grade 0, no microbubbles; grade 1, &lt; 30 microbubbles; grade 2, 30-100 microbubbles; grade 3, &gt; 100 microbubbles) was performed according to contrast opacification of the left ventricle. Cerebral complications were defined as ischemic stroke, transient ischemic attack, or brain abscess diagnosed by a neurologist and confirmed by appropriate imaging techniques.

RESULTS

A pulmonary RLS was present in 530 out of 1,038 patients (51.1%; mean age, 44.3 ± 15.6 years; 58.6% women). The presence of a cerebral manifestation (n = 51) differed significantly among pulmonary shunt grades on TTCE: 1.4%, 0.4%, 6.5%, and 20.9% for grades 0, 1, 2 and 3, respectively. A pulmonary shunt grade 1 was not associated with an increased prevalence of cerebral manifestations (OR, 0.44; 95% CI, 0.05-4.13; P = .47), whereas pulmonary shunt grade 2 (OR, 4.78; 95% CI, 1.14-20.0; P = .03) and grade 3 (OR, 10.4; 95% CI, 2.4-45.3; P = .002) were both independent predictors for the prevalence of a cerebral ischemic event or brain abscess.

CONCLUSIONS

The pulmonary RLS grade on TTCE is strongly associated with the prevalence of cerebral complications in patients screened for HHT.

Pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVMs) are abnormal vascular structures that most often connect a pulmonary artery to a pulmonary vein, bypassing the normal pulmonary capillary bed and resulting in an intrapulmonary right-to-left shunt. As a consequence, patients with PAVM can have hypoxemia and paradoxical embolization complications, including stroke and brain abscess. PAVMs may be single or multiple, unilateral or bilateral, and simple or complex. Most PAVMs are hereditary and occur in hereditary hemorrhagic telangiectasia, an autosomal dominant vascular disorder, and screening for PAVM is indicated in this subgroup. PAVMs may also be idiopathic, occur as a result of trauma and infection, or be secondary to hepatopulmonary syndrome and bidirectional cavopulmonary shunting. Diagnostic testing involves identifying an intrapulmonary shunt, with the most sensitive test being transthoracic contrast echocardiography. Chest CT scan is useful in characterizing PAVM in patients with positive intrapulmonary shunting. Transcatheter embolotherapy is the treatment of choice for PAVM. Lifelong follow-up is important because recanalization and collateralization may occur after embolization therapy. Surgical resection is rarely necessary and reserved for patients who are not candidates for embolization. Antibiotic prophylaxis for procedures with a risk of bacteremia (eg, dental procedures) is recommended in all patients with PAVM because of the risk of cerebral abscess.

Role of transthoracic contrast echocardiography in the clinical diagnosis of hereditary hemorrhagic telangiectasia

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) can be diagnosed according to the four clinical Curaçao criteria, including the presence of pulmonary arteriovenous malformations (PAVMs). In the past few years, transthoracic contrast echocardiography (TTCE) replaced chest high-resolution CT (HRCT) imaging for the screening of PAVMs. The objective of this study was to determine whether the presence of any pulmonary shunt on TTCE can be accepted as a new clinical Curaçao criterion in diagnosing HHT.

METHODS

Between 2004 and 2012, we included 487 first-degree relatives of known HHT-causing mutation carriers who underwent both TTCE and chest HRCT imaging to screen for PAVMs. A quantitative three-point grading scale was used to differentiate among minimal, moderate, or extensive pulmonary shunt on TTCE (grade 1-3). Genetic testing was performed in all people and considered the gold standard for the diagnosis of HHT.

RESULTS

Chest HRCT imaging demonstrated PAVMs in 114 of 218 patients (52.3%) with a pulmonary shunt on TTCE. The addition of any pulmonary shunt on TTCE to the current clinical Curaçao criteria increased the number of positive criteria in 92 of 487 individuals (18.9%), which increased the sensitivity in diagnosing HHT from 88% to 94% at the expense of a decreased specificity from 74% to 70%. Accepting only pulmonary shunt grades ≥ 2 on TTCE as a diagnostic criterion for HHT enhanced the number of positive criteria in 30 (6.2%) individuals, which led to an increased sensitivity of 90% with no decrease in specificity (74%).

CONCLUSIONS

The addition of only pulmonary shunt grades ≥ 2 on TTCE to the current clinical Curaçao criteria increases its sensitivity without affecting specificity in the diagnosis of HHT.

The 'anatomic shunt test' in clinical practice; contemporary description of test and in-service evaluation

The 100% oxygen shunt test for detecting right-to-left anatomical shunting was originally described 70 years ago. However, its clinical value is not yet established. We conducted an audit in 80 patients undergoing the test between 1996 and 2012 in a tertiary referral centre. A significant difference (p=0.02) existed between the median shunt percentages where anatomical shunting was identified (10.2%) and absent (5.0%). The area under the curve for a ROC plot was 0.70. A shunt percentage of 8.3 had a sensitivity of 80% and specificity of 75% for detection of an anatomic shunt. We conclude the test is satisfactory for the first-line investigation for anatomic shunting.

Diagnosis and treatment of pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia: An overview

Hereditary hemorrhagic telangiectasia (HHT) or Rendu-Osler-Weber disease is an autosomic dominant disorder, which is characterized by the development of multiple arteriovenous malformations in either the skin, mucous membranes, and/or visceral organs. Pulmonary arteriovenous malformations (PAVMs) may either rupture, and lead to life-threatening hemoptysis/hemothorax or be responsible for a right-to-left shunting leading to paradoxical embolism, causing stroke or cerebral abscess. PAVMs patients should systematically be screened as the spontaneous complication rate is high, by reaching almost 50%. Neurological complications rate is considerably higher in patients presenting with diffuse pulmonary involvement. PAVM diagnosis is mainly based upon transthoracic contrast echocardiography and CT scanner examination. The latter also allows the planification of treatments to adopt, which consists of percutaneous embolization, having replaced surgery in most of the cases. The anchor technique consists of percutaneous coil embolization of the afferent pulmonary arteries of the PAVM, by firstly placing a coil into a small afferent arterial branch closely upstream the PAVM. Enhanced contrast CT scanner is the key follow-up examination that depicts the PAVM enlargement, indicating the various mechanisms of PAVM reperfusion. When performed by experienced operators as the prime treatment, percutaneous embolization of PAVMs, is a safe, efficient and sustained therapy in the great majority of HHT patients.

Hereditary hemorrhagic telangiectasia: how accurate are the clinical criteria?

The clinical diagnosis of hereditary hemorrhagic telangiectasia (HHT) is based on the Curaçao criteria. Three out of four criteria are required for a definite clinical diagnosis HHT, two criteria are considered "possible" HHT, and 0 or 1 criterion makes the diagnosis unlikely. However, these consensus diagnostic criteria have not been validated. We report on the diagnostic accuracy of the clinical criteria. A total of 450 consecutive persons ≥16 years of age were screened for HHT between May 2004 and September 2009, including a chest CT to screen for pulmonary arteriovenous malformations (AVMs). We selected 263 first-degree relatives of disease-causing mutation carriers who underwent mutation analysis. Genetic test results were considered the gold standard. The family mutation was present in 186 patients (mean age 42.9 ± 14.6 yr; 54.8% female). A clinical diagnosis was definite, "possible", and unlikely in 168 (90.3%), 17 (9.1%), and 1 (0.5%) patient, respectively. In 77 persons the family mutation was absent (mean age 37.1 ± 12.3 yr, 59.7% female). In this group a clinical diagnosis was definite, possible, and unlikely in 0, 35 (45.5%), and 42 (54.5%) persons, respectively. The positive predictive value of a definite clinical diagnosis was 100% (95% CI 97.8-100), the negative predictive value of an unlikely diagnosis 97.7% (95% CI 87.9-99.6). Of 52 patients with "possible" HHT, 17 (32.7%) displayed an HHT-causing mutation. The Curaçao clinical criteria have a good diagnostic performance. Genetic testing is particularly helpful in patients with a "possible" clinical diagnosis HHT.

Hereditary hemorrhagic telangiectasia patients can tolerate anticoagulation

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder characterized by arteriovenous malformations (AVMs) and hemorrhage. HHT patients can also suffer from unrelated medical conditions requiring anticoagulant or antiplatelet treatment (collectively "AT"), though clinicians generally consider HHT a contraindication to AT. We hypothesized that HHT patients can tolerate AT with minimal hemorrhage. Through a chart review of 469 definite HHT patients (1997-2009), we found that 64 (14 %) had received AT. Forty-three out of 64 (67 %) underwent a telephone survey to retrospectively inquire about prescription, early cessation, and HHT-related bleeding. At the time of the study, nine patients were deceased, nine declined, and three were unreachable. During AT treatment, ten (23 %) reported severe complications (blood transfusion, emergency room visit, or hospital admission), while 25 (58 %) reported minor complications (increase or development of epistaxis, gastrointestinal bleeding, and anemia). No patients reported pulmonary/cerebral hemorrhage. The 43 patients received a total of 69 courses of AT. Fourteen out of 69 (20 %) AT courses in 13 patients required early cessation, mostly due to epistaxis. Two out of nine (22 %) deceased patients required early cessation. We conclude that HHT patients can be treated with AT but should be monitored closely given their risk for worsening chronic bleeding and should be screened/treated for pulmonary or cerebral AVMs prior to AT treatment.

Utility of contrast echocardiography for pulmonary arteriovenous malformation screening in pediatric hereditary hemorrhagic telangiectasia

OBJECTIVE

To evaluate the utility of transthoracic contrast echocardiography (TTCE) as a screening tool for pulmonary arteriovenous malformations (PAVMs) in children with hereditary hemorrhagic telangiectasia (HHT).

STUDY DESIGN

This was a single-center study of children who underwent baseline screening for PAVMs using both TTCE and chest computed tomography (CT) for evaluation of HHT. The CT and TTCE results were prospectively reviewed independently by 2 radiologists and 2 cardiologists blinded to the study results.

RESULTS

Both intraobserver and interobserver agreement for interpreting TTCE results were excellent (κ = 0.97 and 0.92, respectively) and higher than the interobserver agreement for CT interpretation (κ = 0.75). The sensitivity and specificity of TTCE to predict PAVMs were 1 and 0.82, respectively, and the positive predictive and negative predictive values were 0.39 and 1, respectively.

CONCLUSION

TTCE is a sensitive test for PAVMs in children with suspected HHT and can be a useful initial screening tool in pediatric HHT.