Agitated Saline Contrast Echocardiography Research Articles

The predictive value of abnormal electrocardiogram for patent foramen ovale: A retrospective study.

The objective of this study was to identify the characteristics of electrocardiogram (ECG) in adult patients with patent foramen ovale (PFO)and to analyze the predictive value of the characteristics of ECG for PFO in adult patients. Retrospectively, 267 patients who had undergoneECG, transthoracic echocardiography (TTE), transesophageal echocardiography (TEE) with agitated saline contrastechocardiography in our hospital, were recruited continuously from January2021 to March2023. Electrocardiographs were analyzed to investigate the presence of right bundle branch block (RBBB) and crochetage R wave. The ratio of crochetage R wave in inferior leads in patients with PFO was 45.3% and 21.2% without PFO. There were 17 (6.4%) patients with coexistence of crochetage R wave and RBBB, including 13 (6.5%) patients with PFO and four (6.1%) patients without PFO. The accuracies of TTE, crochetage R wave, and RBBB were 0.637, 0.535, and 0.314, respectively. A combination of crochetage R wave and RBBB demonstrated a sensitivity of 0.507 and a specificity of 0.758. When TTE, crochetage R wave, and RBBB were combined, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 0.712, 0.801, 0.439, 0.813, and 0.420, respectively. Logistic regression analysis revealed a correlation between PFO and the presence of crochetage R wave (odds ratio[OR]: 3.073, 95% confidence interval [CI]: 1.601-5.899, p < 0.001), and also a combination between crochetage R wave and RBBB (OR: 3.220, 95% CI: 1.720-6.028, p < 0.001). Crochetage R wave in ECG was associated with PFO. Crochetage R wave, especially combined with RBBB and TTE, may be helpful in the early detection of patients withPFO.

White matter lesions predominantly located in deep white matter represent embolic etiology rather than small vessel disease

AbstractBackgroundIndividuals with cerebral small vessel disease (CSVD) usually have both periventricular and deep white matter hyperintensities (dpWMH). However, we often encounter individuals whose WMH lesions are mainly located in the corticomedullary or deep white matter with minimal periventricular WMHs (dWMH). We aimed to determine if the dWMH pattern could be attributed to embolic etiologies.MethodsWe retrospectively recruited participants who had undergone comprehensive dementia evaluation, agitated saline contrast echocardiography, and brain MRI. The participants were classified into two groups according to WMH distributions, the dWMH (WMHs in deep and corticomedullary area, with minimal periventricular WMHs) and the dpWMH (mainly periventricular WMHs with or without deep WMHs) groups. We hypothesized that dWMH is more likely associated with embolism, whereas dpWMH with CSVD. We compared the clinical characteristics, WMH distributions, and the positive rate of agitated saline study between the two groups.ResultsOf the 90 participants, 27 fulfilled the dWMH criteria and 12 met the dpWMH criteria. The dWMH group was younger (62.2±7.5 vs 78.9±7.3, p&lt;0.001), and had a lower prevalence of hypertension (29.6% vs. 75%, p = 0.008), DM (3.7% vs. 25%, p = 0.043), and hyperlipidemia (33.3% vs. 83.3%, p = 0.043) than the dpWMH group. Regarding deep white matter lesions, the number of small lesions (&lt;3 mm) was higher in the dWMH (10.9±9.7) than the dpWMH (3.1±6.4) group (p = 0.008), and WMHs were predominantly distributed in border‐zones of major cerebral arteries and corticomedullary areas.Most importantly, the positive rate of agitated saline was higher in the dWMH than the dpWMH group (81.5% vs. 33.3%, p = 0.003).ConclusionsThe dWMH group with younger age, fewer cardiovascular risk factors showed more border‐zone distributions, and higher positivity of agitated saline test than dpWMH group, indicating that WMH distributions mainly in the corticomedullary or deep area with minimal periventricular WMH lesions suggest embolic etiologies.

Absent right superior vena cava and persistent left superior vena cava: An incidental finding.

A patient with Marfan syndrome undergoing Bentall operation was found to have an absent right superior vena cava and persistent left superior vena cava. The dilation of coronary sinus raised the suspicion of persistent left superior vena cava. The diagnosis was confirmed by agitated saline contrast echocardiography and computed tomography of the chest.

White Matter Lesions Predominantly Located in Deep White Matter Represent Embolic Etiology Rather Than Small Vessel Disease

We investigated the correlation between the deep distribution of white matter hyperintensity (WMH) (dWMH: WMH in deep and corticomedullary areas, with minimal periventricular WMH) and a positive agitated saline contrast echocardiography result. We retrospectively recruited participants with comprehensive dementia evaluations, an agitated saline study, and brain imaging. The participants were classified into two groups according to WMH-distributions: dWMH and dpWMH (mainly periventricular WMH with or without deep WMH.) We hypothesized that dWMH is more likely associated with embolism, whereas dpWMH is associated with small-vessel diseases. We compared the clinical characteristics, WMH-distributions, and positive rate of agitated saline studies between the two groups. Among 90 participants, 27 and 12 met the dWMH and dpWMH criteria, respectively. The dWMH-group was younger (62.2±7.5 vs. 78.9±7.3, p<0.001) and had a lower prevalence of hypertension (29.6% vs. 75%, p=0.008), diabetes mellitus (3.7% vs. 25%, p=0.043), and hyperlipidemia (33.3% vs. 83.3%, p=0.043) than the dpWMH-group. Regarding deep white matter lesions, the number of small lesions (<3 mm) was higher in the dWMH-group(10.9±9.7) than in the dpWMH-group (3.1±6.4) (p=0.008), and WMH was predominantly distributed in the border-zones and corticomedullary areas. Most importantly, the positive agitated saline study rate was higher in the dWMH-group than in the dpWMH-group (81.5% vs. 33.3%, p=0.003). The dWMH-group with younger participants had fewer cardiovascular risk factors, showed more border-zone-distributions, and had a higher agitated saline test positivity rate than the dpWMH-group, indicating that corticomedullary or deep WMH-distribution with minimal periventricular WMH suggests embolic etiologies.

Perfusion of Intrapulmonary Arteriovenous Anastomoses Is Not Related to VO2max in Hypoxia and Is Unchanged by Oral Sildenafil.

Background: Perfusion of intrapulmonary arteriovenous anastomoses (IPAVA) is increased during exercise and in hypoxia and is associated with variations in oxygen saturation (SPO2), resulting in blood bypassing the pulmonary microcirculation. Sildenafil is a pulmonary vasodilator that improves SPO2 and endurance performance in hypoxia. The purpose of this study was to determine if 50 mg sildenafil would reduce IPAVA perfusion (QIPAVA) and if the decrement in maximal exercise capacity (VO2max) in hypoxia is related to QIPAVA. We hypothesized that during progressive levels of hypoxia at rest (FIO2 = 0.21, 0.14, 0.12), sildenafil would increase SPO2 and reduce bubble score (estimate of QIPAVA) compared to placebo, and that the decrement in VO2max in hypoxia would be positively correlated with bubble score at rest in hypoxia. Materials and Methods: Fourteen endurance-trained men performed a graded maximal exercise test at sea level and at a simulated altitude of 3000 m, followed by two experimental visits where, after randomly ingesting sildenafil or placebo, they underwent agitated saline contrast echocardiography during progressive levels of hypoxia at rest. Results: All participants experienced a decrement in power output in hypoxia that ranged from 9% to 19% lower than sea level values. Compared to normoxia, bubble score increased significantly in hypoxia (p < 0.001) with no effect of sildenafil (p = 0.580). There was a negative correlation between SPO2 and bubble score (p < 0.001). The decrement in peak power output at VO2max in hypoxia was unrelated to IPAVA perfusion in resting hypoxia (p = 0.32). Several participants demonstrated QIPAVA greater than zero in room air, indicating that arterial hypoxemia may not be the sole mechanism for QIPAVA. Conclusion: These results indicate that the VO2max decrement caused by hypoxia is not related to QIPAVA and that sildenafil does not improve VO2max in hypoxia through modulation of QIPAVA.

INTRAPULMONARY SHUNTING IN CARCINOID SYNDROME

SESSION TITLE: Pulmonary Manifestations of Systemic Disease SESSION TYPE: Fellow Case Reports PRESENTED ON: 10/21/2019 3:15 PM - 4:15 PM INTRODUCTION: Carcinoid tumors are rare slow-growing neuroendocrine tumors. The biologic behavior of these tumors can be variable and unpredictable which may lead to unusual clinical presentations and delayed diagnosis. Carcinoid tumors release different vasoactive substances, including serotonin, histamine, and bradykinins. Release of 5-hydroxyindoleacetic acid (5-HIAA), a product of serotonin degradation, results in increased gastrointestinal motility (diarrhea), bronchoconstriction (wheezing), and vasodilation (flushing). Intra-pulmonary shunt (hepatopulmonary-like syndrome) due to pulmonary vasodilatation of the microvascular bed is exceedingly rare in carcinoid syndrome. CASE PRESENTATION: A 57-year-old man presented with chronic diarrhea and flushing. Initially, the diarrhea was believed to be related to metformin, however it persisted despite stopping this medication. Later, he developed progressive dyspnea with profound hypoxia. Hypoxemia was poorly responsive to supplemental oxygen, consistent with shunt physiology. Work up for hypoxia included an unremarkable chest radiograph and arterial blood gas with increased alveolar-arterial gradient. Chest CT angiography was negative for pulmonary embolism or parenchymal lung disease. Inhaled oxygen shunt study revealed 23.3% shunt. Agitated saline contrast echocardiography showed no evidence of intracardiac shunt, but demonstrated late bubbles (>5 beats) in the left side after agitated saline administration consistent with intra-pulmonary shunt. CT of the abdomen demonstrated enlarged and markedly heterogeneous liver concerning for metastatic disease, as well as a 2.6 x 3.0 cm mass in the small bowel mesentery, morphologically consistent with carcinoid tumor. Serum serotonin, 24 hour urine 5 HIAA, and serum chromogranin A level were abnormally elevated. Biopsy of a liver lesion confirmed a well-differentiated neuroendocrine carcinoma, classified as low grade with a Ki-67 of less than 2%. He was initiated on first line therapy with Sandostatin LAR with rapid resolution of his diarrhea. While he remains hypoxic and oxygen dependent, his subjective dyspnea has improved. DISCUSSION: Severe hypoxemia has been described in carcinoid syndrome mostly due to right to left cardiac shunts; however, carcinoid-related intrapulmonary shunt is exceedingly rare. To our knowledge, only three cases of intrapulmonary shunt in carcinoid syndrome have been reported (1-3). Similar to our patient, these were associated with metastatic disease. CONCLUSIONS: Possible mechanisms of hypoxemia in carcinoid syndrome warrant further investigation. Reference #1: Hussain A, Young ET, Greaves JD, et al. Intrapulmonary shunting causing hypoxaemia in a case of carcinoid syndrome. Clin Endocrinol (Oxf). 1994;41(4):535-537. Reference #2: Robert R, Matuchansky C, Picker F, Guitton P, Patte D. Severe hypoxemia in a case of midgut carcinoid tumor. Intensive Care Med. 1989;15(8):536-537. Reference #3: Stewart GW, Freegard SP, Keeling DH, Perrett AD. Cyanosis attributable to right to left shunt in carcinoid syndrome. Br Med J (Clin Res Ed). 1986;292(6520):589-590. DISCLOSURES: No relevant relationships by Mazen Al-Qadi, source=Web Response Consultant relationship with United Therapeutics Please note: $5001 - $20000 Added 02/14/2019 by Hubert Ford, source=Web Response, value=Travel also Consultant relationship with Actelion Please note: $1001 - $5000 Added 03/14/2019 by Hubert Ford, source=Web Response, value=Honoraria Consultant relationship with Liquidia Please note: $1-$1000 Added 03/14/2019 by Hubert Ford, source=Web Response, value=Honoraria Research Grant relationship with United Therapeutics Please note: $5001 - $20000 Added 03/14/2019 by Hubert Ford, source=Web Response, value=Grant/Research Support No relevant relationships by Amanda Kovacich, source=Web Response No relevant relationships by Autumn McRee, source=Web Response

Intra-pulmonary arteriovenous anastomoses and pulmonary gas exchange: evaluation by microspheres, contrast echocardiography and inert gas elimination.

Imaging techniques such as contrast echocardiography suggest that anatomical intra-pulmonary arteriovenous anastomoses (IPAVAs) are present at rest and are recruited to a greater extent in conditions such as exercise. IPAVAs have the potential to act as a shunt, although gas exchange methods have not demonstrated significant shunt in the normal lung. To evaluate this discrepancy, we compared anatomical shunt with 25-µm microspheres to contrast echocardiography, and gas exchange shunt measured by the multiple inert gas elimination technique (MIGET). Intra-pulmonary shunt measured by 25-µm microspheres was not significantly different from gas exchange shunt determined by MIGET, suggesting that MIGET does not underestimate the gas exchange consequences of anatomical shunt. A positive agitated saline contrast echocardiography score was associated with anatomical shunt measured by microspheres. Agitated saline contrast echocardiography had high sensitivity but low specificity to detect a ≥1% anatomical shunt, frequently detecting small shunts inconsequential for gas exchange. The echocardiographic visualization of transpulmonary agitated saline microbubbles suggests that anatomical intra-pulmonary arteriovenous anastomoses are recruited during exercise, in hypoxia, and when cardiac output is increased pharmacologically. However, the multiple inert gas elimination technique (MIGET) shows insignificant right-to-left gas exchange shunt in normal humans and canines. To evaluate this discrepancy, we measured anatomical shunt with 25-µm microspheres and compared the results to contrast echocardiography and MIGET-determined gas exchange shunt in nine anaesthetized, ventilated canines. Data were acquired under the following conditions: (1) at baseline, (2) 2µgkg-1 min-1 i.v. dopamine, (3) 10µgkg-1 min-1 i.v. dobutamine, and (4) following creation of an intra-atrial shunt (in four animals). Right to left anatomical shunt was quantified by the number of 25-µm microspheres recovered in systemic arterial blood. Ventilation-perfusion mismatch and gas exchange shunt were quantified by MIGET and cardiac output by direct Fick. Left ventricular contrast scores were assessed by agitated saline bubble counts, and separately by appearance of 25-µm microspheres. Across all conditions, anatomical shunt measured by 25-µm microspheres was not different from gas exchange shunt measured by MIGET (microspheres: 2.3±7.4%; MIGET: 2.6±6.1%, P=0.64). Saline contrast bubble score was associated with microsphere shunt (ρ=0.60, P<0.001). Agitated saline contrast score had high sensitivity (100%) to detect a ≥1% shunt, but low specificity (22-48%). Gas exchange shunt by MIGET does not underestimate anatomical shunt measured using 25-µm microspheres. Contrast echocardiography is extremely sensitive, but not specific, often detecting small anatomical shunts which are inconsequential for gas exchange.

Reduced blood flow through intrapulmonary arteriovenous anastomoses during exercise in lowlanders acclimatizing to high altitude.

What is the central question of this study? The aim was to determine, using the technique of agitated saline contrast echocardiography, whether exercise after 4-7days at 5050m would affect blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) compared with exercise at sea level. What is the main finding and its importance? Despite a significant increase in both cardiac output and pulmonary pressure during exercise at high altitude, there is very little Q̇IPAVA at rest or during exercise after 4-7days of acclimatization. Mathematical modelling suggests that bubble instability at high altitude is an unlikely explanation for the reduced Q̇IPAVA. Blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) is elevated during exercise at sea level (SL) and at rest in acute normobaric hypoxia. After high altitude (HA) acclimatization, resting Q̇IPAVA is similar to that at SL, but it is unknown whether this is true during exercise at HA. We reasoned that exercise at HA (5050m) would exacerbate Q̇IPAVA as a result of heightened pulmonary arterial pressure. Using a supine cycle ergometer, seven healthy adults free from intracardiac shunts underwent an incremental exercise test at SL [25, 50 and 75% of SL peak oxygen consumption (V̇O2 peak )] and at HA (25 and 50% of SL V̇O2 peak ). Echocardiography was used to determine cardiac output (Q̇) and pulmonary artery systolic pressure (PASP), and agitated saline contrast was used to determine Q̇IPAVA (bubble score; 0-5). The principal findings were as follows: (i) Q̇ was similar at SL rest (3.9±0.47lmin-1 ) compared with HA rest (4.5±0.49lmin-1 ; P=0.382), but increased from rest during both SL and HA exercise (P<0.001); (ii) PASP increased from SL rest (19.2±0.7mmHg) to HA rest (33.7±2.8mmHg; P=0.001) and, compared with SL, PASP was further elevated during HA exercise (P=0.003); (iii) Q̇IPAVA was increased from SL rest (0) to HA rest (median=1; P=0.04) and increased from resting values during SL exercise (P<0.05), but was unchanged during HA exercise (P=0.91), despite significant increases in Q̇ and PASP. Theoretical modelling of microbubble dissolution suggests that the lack of Q̇IPAVA in response to exercise at HA is unlikely to be caused by saline contrast instability.

Is There A Relationship Between Pulmonary Capillary Blood Volume And Intrapulmonary Arteriovenous Anastomosis Recruitment During Exercise?

Exercise results in the recruitment of anatomical intrapulmonary arteriovenous anastomoses (IPAVA). There is speculation that IPAVA recruitment may act as a ‘pop‐off’ valve once pulmonary capillaries are fully recruited during exercise to protect the lung from large increases in pulmonary arterial pressure. Recognizing that the pulmonary capillaries are fully recruited in the supine position, we hypothesized that IPAVA recruitment during incremental exercise would initially occur at a pulmonary capillary blood volume (Vc) that approximated the value observed in the supine position. Twenty healthy subjects (9 males, 11 females, means±SD, age: 27±7 yrs, VO2max: 49.9±10.5 mL·kg−1·min−1) performed cycling exercise at 30, 50, 70 and 90% of VO2max. Capillary blood volume (Vc) was determined using the multiple FIO2‐DLCO breath‐hold method in the supine and upright positions at rest, as well as during upright exercise. IPAVA recruitment was evaluated by agitated saline contrast echocardiography. Mean Vc was 80.2±17.2 mL in the resting upright position, which increased to 94.6±24.6 mL when supine (p=0.043). During incremental upright exercise, Vc increased up to 132.9±26.3 mL at peak exercise (p&lt;0.01). IPAVA recruitment was detected in all subjects during exercise, and first occurred at a mean Vc of 93.8±16.0 mL, which is significantly greater than resting upright Vc (p&lt;0.05), but similar to resting supine Vc (p=0.97). Results were similar in men compared to women, and results were consistent when adjusting for alveolar volume. IPAVA recruitment was observed at a capillary blood volume similar to the value observed in the supine position. As the supine position is widely believed to result in the perfusion of all pulmonary capillaries, these data support the hypothesis that recruitment of IPAVAs follows full recruitment of the pulmonary capillaries.Support or Funding InformationProject funding provided by the Natural Sciences and Engineering Research Council (NSERC, PI M. Stickland), and the Canadian Respiratory Research Network (CRRN, PI M. Stickland). V. Tedjasaputra is supported by the The Lung Association of Alberta and NWT graduate studentship. M. Bouwsema was supported by NSERC and Alberta Innovates Health Solutions summer studentships.

Dopamine receptor blockade improves pulmonary gas exchange but decreases exercise performance in healthy humans.

Pulmonary gas exchange, as evaluated by the alveolar-arterial oxygen difference (A-aDO2), is impaired during intense exercise, and has been correlated with recruitment of intrapulmonary arteriovenous anastomoses (IPAVA) as measured by agitated saline contrast echocardiography. Previous work has shown that dopamine (DA) recruits IPAVA and increases venous admixture (Q̇s/Q̇t) at rest. As circulating DA increases during exercise, we hypothesized that A-aDO2 and IPAVA recruitment would be decreased with DA receptor blockade. Twelve healthy males (age: 25 ± 6 years, V̇O2 max : 58.6 ± 6.5 ml kg(-1) min(-1) ) performed two incremental staged cycling exercise sessions after ingestion of either placebo or a DA receptor blocker (metoclopramide 20 mg). Arterial blood gas, cardiorespiratory and IPAVA recruitment (evaluated by agitated saline contrast echocardiography) data were obtained at rest and during exercise up to 85% of V̇O2 max . On different days, participants also completed incremental exercise tests and exercise tolerance (time-to-exhaustion (TTE) at 85% of V̇O2 max ) with or without dopamine blockade. Compared to placebo, DA blockade did not change O2 consumption, CO2 production, or respiratory exchange ratio at any intensity. At 85% V̇O2 max , DA blockade decreased A-aDO2, increased arterial O2 saturation and minute ventilation, but did not reduce IPAVA recruitment, suggesting that positive saline contrast is unrelated to A-aDO2. Compared to placebo, DA blockade decreased maximal cardiac output, V̇O2 max and TTE. Despite improving pulmonary gas exchange, blocking dopamine receptors appears to be detrimental to exercise performance. These findings suggest that endogenous dopamine is important to the normal cardiopulmonary response to exercise and is necessary for optimal high-intensity exercise performance.

Hypoxia, not pulmonary vascular pressure, induces blood flow through intrapulmonary arteriovenous anastomoses.

Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased by acute hypoxia during rest by unknown mechanisms. Oral administration of acetazolamide blunts the pulmonary vascular pressure response to acute hypoxia, thus permitting the observation of IPAVA blood flow with minimal pulmonary pressure change. Hypoxic pulmonary vasoconstriction was attenuated in humans following acetazolamide administration and partially restored with bicarbonate infusion, indicating that the effects of acetazolamide on hypoxic pulmonary vasoconstriction may involve an interaction between arterial pH and PCO2. We observed that IPAVA blood flow during hypoxia was similar before and after acetazolamide administration, even after acid-base status correction, indicating that pulmonary pressure, pH and PCO2 are unlikely regulators of IPAVA blood flow. Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased with exposure to acute hypoxia and has been associated with pulmonary artery systolic pressure (PASP). We aimed to determine the direct relationship between blood flow through IPAVA and PASP in 10 participants with no detectable intracardiac shunt by comparing: (1) isocapnic hypoxia (control); (2) isocapnic hypoxia with oral administration of acetazolamide (AZ; 250 mg, three times a day for 48 h) to prevent increases in PASP; and (3) isocapnic hypoxia with AZ and 8.4% NaHCO3 infusion (AZ + HCO3 (-) ) to control for AZ-induced acidosis. Isocapnic hypoxia (20 min) was maintained by end-tidal forcing, blood flow through IPAVA was determined by agitated saline contrast echocardiography and PASP was estimated by Doppler ultrasound. Arterial blood samples were collected at rest before each isocapnic-hypoxia condition to determine pH, [HCO3(-)] and Pa,CO2. AZ decreased pH (-0.08 ± 0.01), [HCO3(-)] (-7.1 ± 0.7 mmol l(-1)) and Pa,CO2 (-4.5 ± 1.4 mmHg; P < 0.01), while intravenous NaHCO3 restored arterial blood gas parameters to control levels. Although PASP increased from baseline in all three hypoxic conditions (P < 0.05), a main effect of condition expressed an 11 ± 2% reduction in PASP from control (P < 0.001) following AZ administration while intravenous NaHCO3 partially restored the PASP response to isocapnic hypoxia. Blood flow through IPAVA increased during exposure to isocapnic hypoxia (P < 0.01) and was unrelated to PASP, cardiac output and pulmonary vascular resistance for all conditions. In conclusion, isocapnic hypoxia induces blood flow through IPAVA independent of changes in PASP and the influence of AZ on the PASP response to isocapnic hypoxia is dependent upon the H(+) concentration or Pa,CO2.

Absent Right Superior Vena Cava with Persistent Left Superior Vena Cava Which Drains to Unroofed Coronary Sinus in a Child with Atrioventricular Septal Defect and Cor Triatriatum Sinister: Preop Correct Diagnosis and Successful Surgery in a Single Session

We report a unique case of a 4-year-old boy with intermediate-type atrioventricular septal defect, cor triatriatum sinister, persistent left superior vena cava, unroofed coronary sinus, and absent right superior vena cava. Persistent left vena cava draining into the unroofed coronary sinus was demonstrated easily using the agitated saline-contrast echocardiography. After conformation with angiographic evaluation, surgery was performed at a single session. Roofing of the coronary sinus with polytetrafluoroethylene patch, mitral cleft repair, tricuspid annuloplasty, atrioventricular defect repair with pericardial patch, and resection of the membrane in the left atrium was succeeded without complication.

EXERCISE TREADMILL SALINE CONTRAST ECHOCARDIOGRAPHY FOR THE DETECTION OF PATENT FORAMEN OVALE IN HYPOXIC PATIENTS

Percutaneous patent foramen ovale (PFO) closure improves hypoxia and dyspnea in selected patients with PFO-mediated right-to-left shunt (RLS). Agitated saline contrast echocardiography (SCE) performed at rest is frequently used to identify PFOs in hypoxic patients. SCE performed with exercise may

Exercise-induced intrapulmonary arteriovenous shunt in healthy women

The purpose of this study was to determine if healthy young women of various aerobic fitness levels are vulnerable to intrapulmonary arteriovenous shunts (IPAVS) at sub maximal work rates. Female volunteers (n=24) performed semi-recumbent cycling exercise to exhaustion and agitated saline contrast echocardiography was used to determine the presence of IPAVS at rest, during exercise, and post exercise. Subjects were classified as untrained (UT, n=8), moderately trained (MT, n=6) and highly trained (HT, n=10) based on their respective (V(O(2,peak)) (UT=35±5; MT=43±1 and HT = 50 ± 3 ml kg(-1) min(-1)). We found that the % (V(O(2,peak)) at IPAVS onset was not significantly different between women of varying fitness (P>0.05). The majority of individuals exhibited IPAVS during modest levels of exercise intensity. In conclusion, there is no association between aerobic capacity or exercise intensity at IPAVS onset in women performing semi-recumbent cycle exercise.

Agitated saline contrast use in a case with peripheral pulmonary artery stenosis

We present a case of peripheral pulmonary artery stenosis that was incidentally detected by agitated saline contrast study. A 19-year-old male patient underwent cardiologic examination to determine suitability for military service. He had exertional intolerance since early childhood. Physical examination showed a murmur over the entire right hemithorax. Echocardiography showed moderately enlarged right ventricle, right atrium, and main pulmonary artery, and color Doppler showed mild tricuspid regurgitation. Right ventricular systolic pressure was estimated as 55-60 mmHg from the tricuspid regurgitation jet. For further evaluation of the systolic murmur, agitated saline contrast echocardiography was performed. During continuous wave Doppler examination while there were remnants of bubbles in the right heart and pulmonary vascular bed, a systolodiastolic flow with a peak gradient of 30 mmHg was noted. After disappearance of the bubbles, the signal was not detectable. Repeat agitated saline contrast examination again showed a gradient of 35 mmHg. A stenosis in the distal branches of the right pulmonary artery was suspected. Finally, computed tomography revealed multiple stenoses in the pulmonary vascular bed. To our best knowledge, this is the first case in which agitated saline contrast examination enabled the diagnosis of peripheral pulmonary artery stenosis.

Comments on Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

Comments on Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

Saline Contrast Echocardiography in Patients With Hepatopulmonary Syndrome Awaiting Liver Transplantation

Patients with hepatopulmonary syndrome (HPS) with end-stage liver disease (ESLD) have higher cardiorespiratory mortality than those without. The aims of this study were to determine whether echocardiography could distinguish patients with ESLD with and without HPS and whether the diagnosis of HPS by contrast echocardiography (CE) was altered by the performance of the test in a supine or standing position. Subjects were recruited prospectively from patients with end-stage liver disease undergoing assessment for liver transplantation. Hepatopulmonary syndrome was diagnosed on the basis of arterial blood gas analysis, lung function testing and agitated saline contrast echocardiography in the absence of primary cardiac or pulmonary disease. Bubble contrast injections were performed supine or standing in a randomised order and read by a blinded observer. CE showed late right-to-left shunting in 13 of 50 consecutive patients with cirrhosis (26%). Eight patients (16%) had definite diagnoses of HPS. CE in the standing position consistently increased both the number and the size of shunts compared with supine injection. CE detected intrapulmonary shunting before a change in arterial blood gases. Standard echocardiographic parameters did not distinguish between those with and without HPS. This study suggests that screening for HPS in patients with advanced cirrhosis should be done using CE with patients in the upright position.

Point:Counterpoint: Exercise-induced intrapulmonary shunting is imaginary vs. real

Pulmonary gas exchange efficiency deteriorates with exercise in both humans and other species, increasing the alveolar-arterial PO2 difference (AaDO2) ([2][1]). The potential contributors to this are ventilation-perfusion inequality, alveolar-capillary diffusion limitation, and shunt ([20][2]).

Agitated saline contrast echocardiography to diagnose a congenital heart defect in a dog

Examination of cardiac structure and function is greatly facilitated by echocardiography, which takes advantage of the natural ultrasonic contrast between myocardial tissue and the blood-filled chambers. In cases where further contrast is desired, peripheral injections of agitated saline, which contain highly reflective gas-filled microbubbles can reveal subtle morphologic lesions as well as characterizing the pattern and timing of blood flow through suspected cardiac shunts or lesions. Agitated saline contrast echocardiography is easily performed and well-tolerated and in this report, we demonstrate the utility of this method to diagnose a rare congenital defect in a dog.

Unroofed Coronary Sinus Associated with Persistent Left Superior Vena Cava : Detection by Agitated Saline Contrast Echocardiography

Unroofed coronary sinus with persistent left superior vena cava is an extremely rare congenital anomaly. It can be suspected by the presence of a markedly dilated coronary sinus and can be confirmed by injection of agitated saline into the left antecubital vein during echocardiography. Agitated saline contrast echocardiography can easily visualize the flow in the persistent left superior vena cava communicating with the unroofed coronary sinus hereby creating a shunt into the left atrium. An agitated saline contrast echocardiography may be performed with a low risk of transient complication. We demonstrate the case of a 32-year-old pregnant woman with unroofed coronary sinus and persistent left superior vena cava, confirmed by agitated saline contrast echocardiography.