Assessing the kinetics of microbubble appearance in cirrhotic patients using transthoracic saline contrast‐enhanced echocardiography

Abstract

Background The number of cardiac cycles that need to be reviewed by echocardiography before a significant intrapulmonary shunt can be excluded remains unclear. Methods We retrospectively identified patients with cirrhosis who underwent technetium-99m-labeled macroaggregated albumin scanning. The kinetics of bubble appearance after the injection of agitated saline during transthoracic echocardiograms were assessed in these patients. Results For the 64 eligible patients, the mean ± SD age was 56 ± 9 years. The median (IQR) shunt fraction by radionuclide scanning was 7.7 % (2.8 – 19.9%). Microbubbles were seen in the left atrium (LA) and left ventricle (LV) at a median (IQR) of 4 (2–5) and 4 (2–5) beats, respectively. The number of heart cycles before microbubbles appeared in the LA or LV was inversely associated with the nuclear scanning shunt fraction (R=−0.42, p=0.001, R=−0.46, p <0.001, respectively). If no microbubbles were detected by heart cycle 7, the shunt fraction was uniformly less than 3%. Patients with arterial oxygen < 60 mmHg, compared to ≥ 60 mmHg, had earlier appearance of microbubbles in the left heart chambers (2.6 ± 1.9 versus 4.0 ± 2.3 beats, p=0.046). Conclusions In patients with advanced cirrhosis suspected of having hepatopulmonary syndrome, a greater shunt fraction during nuclear scanning was associated with more pronounced hypoxemia and a prompt and more intense appearance of microbubbles in the left-sided heart chambers. Patients with a shunt fraction above 3% have microbubbles in the LA or LV at some point during the first seven heart cycles.

Aktualisierte S2k-Leitlinie der Deutschen Gesellschaft für Gastroenterologie, Verdauungs- und Stoffwechselkrankheiten (DGVS) „Komplikationen der Leberzirrhose“

“…Hierfür wird ein normalerweise nicht-lungengängiges Ultraschall-Kontrastmittelderzeit empfohlen ist eine aufgeschüttelte 0,9-prozentige Kochsalzlösung-peripher-venös injiziert und der funktionelle Shunt über die dilatierten Lungengefäße durch die Detektion des Kontrastmittels im linken Herzen verifiziert. Intrakardiale können dabei von intrapulmonalen Shunts zeitlich anhand des Kontrastmittelübertritts vom rechten zum linken Herzen unterschieden werden, typischerweise ein bis zwei Herzschläge bei intrakardialen und zwei bis fünf Herzschläge bei intrapulmonalen pathologischen Veränderungen [417]. Zwar gilt die transösophageale Kontrastmittelechokardiografie als sensitiver für milde Verläufe des HPS, jedoch sollte diese wegen der höheren Invasivität nur bei eingeschränkter transthorakaler Beurteilbarkeit der Untersuchung zur Anwendung kommen [418].…”

A 50-Year-Old Woman With Shortness of Breath

“…1 Hepatopulmonary syndrome causes an extracardiac (intrapulmonary) shunt wherein the injected agitated saline transits through the lung parenchyma and the agitated saline appears in the left-sided heart chambers 2 . In patients diagnosed with hepatopulmonary syndrome with high fraction shunt based on technetium-99mlabeled macro aggregated albumin scanning, left-sided cardiac chambers are typically noted to appear in first seven beats 3 . Thus, hepatopulmonary syndrome alone could not explain the early saline contrast transition from right-to left-sided cardiac chambers.…”

Pulmonary complications in patients with liver cirrhosis

“…In the presence of a functional shunt due to dilated pulmonary vessels, the detection of the contrast medium in the left heart usually takes place after 2–5 heartbeats (in the case of an intracardiac shunt, such as open foramen ovale or atrial septal defect (ASD), usually after 1–2 heartbeats). [ 73 ] Further techniques to detect intrapulmonary shunts are scintigraphy, computed tomography and pulmonary arteriography. Lung perfusion scintigraphy uses 99m-Technetium-macroaggregated human albumin (MAA) (20–50 μm size), which can only cross pulmonary circulation via a right-left shunt.…”