A novel veno-arteriovenous extracorporeal membrane oxygenation with double pump for the treatment of Harlequin syndrome.

OBJECTIVES: The Harlequin syndrome is a complication observed in patients receiving peripheral venoarterial extracorporeal membrane oxygenation. This condition is defined as a critical variation in the oxygen saturation between the upper and the lower part of the body deriving from a poor lung function. METHODS: Between July 2018 and November 2019, a total of 60 patients (42 men and 18 women; mean age 57.4 ± 10.0 years; range = 28-71 years) underwent peripheral venoarterial extracorporeal membrane oxygenation in our center. Harlequin syndrome was identified in eight cases (six men and two women; 13.3%) of the 60 venoarterial extracorporeal membrane oxygenation-supported patients. As a result of the Harlequin syndrome, all these patients required conversion to veno-arteriovenous extracorporeal membrane oxygenation. Control and monitoring of the blood flows of the return cannulae were performed using two centrifugal pumps, one for each inlet line, according to the patient requirements to achieve optimum hemodynamic and oxygenation. RESULTS: Mean duration of veno-arteriovenous extracorporeal membrane oxygenation support was 5.3 ± 1.4 days. Seven patients (87.5%) were switched to venovenous extracorporeal membrane oxygenation, and after 13.5 ± 2.7 days, those patients were totally weaned from extracorporeal membrane oxygenation support. One patient (12.5%) had an improvement in the pulmonary function, but the cardiac function was poor. This patient was switched to venoarterial extracorporeal membrane oxygenation, and after 10 days, the patient was completely weaned from extracorporeal membrane oxygenation support. CONCLUSION: The use of a secondary centrifugal pump to manage the blood flow directed to the internal jugular vein, in the veno-arteriovenous extracorporeal membrane oxygenation setup, allows the reduction in the risk of blood clot formation, clotting factor consumption, and pulmonary embolism when compared to the use of an external clamp.

Weaning from venovenous extracorporeal membrane oxygenation without anticoagulation: is it possible?

A 19-year-old man affected with severe acute respiratory distress syndrome that was unresponsive to medical treatment was successfully weaned without anticoagulation therapy from venovenous extracorporeal membrane oxygenation (ECMO) because of life-threatening bleeding. The patient received venovenous ECMO with double peripheral cannulation. Heparin infusion was discontinued on day 10 for severe bleeding from thoracic and mediastinal drainages until the ECMO was removed. The weaning was performed while keeping the blood flow unchanged, only gas flows were gradually decreased. The patient was discontinued from ECMO and extubated after pulmonary function improved. Based on this single experience, management and weaning without any anticoagulant agent might be possible.

Perindopril and indapamide reverse coronary microvascular remodelling and improve flow in arterial hypertension.

OBJECTIVES: Patients and animal models of arterial hypertension are characterized by structural and functional abnormalities of the coronary microcirculation. Using a translational approach, we ascertained whether antihypertensive treatment can reverse microvascular remodelling and improve myocardial perfusion. METHODS: In 20 hypertensive patients with left ventricular hypertrophy, blood pressure, left ventricular mass index and myocardial blood flow were measured at baseline and after 6 months of treatment with perindopril + indapamide. In spontaneously hypertensive rats, blood pressure, coronary flow and histomorphometry of intramural coronary arterioles were measured after 8 weeks of treatment with placebo or perindopril + indapamide. RESULTS: In patients, treatment decreased blood pressure (161 ± 10/96 ± 5 to 136 ± 12/81 ± 6 mmHg; P < 0.0001) and left ventricular mass index (93 ± 16 to 85 ± 17 g/m; P < 0.01) while increasing baseline (0.69 ± 0.13 to 0.88 ± 0.36 ml/min per g; P < 0.05) and hyperaemic myocardial blood flow (1.42 ± 0.32 to 1.94 ± 0.99 ml/min per g; P < 0.05). In rats treated with perindopril + indapamide (n = 11), blood pressure was 93 ± 18/55 ± 18 mmHg compared to 215 ± 18/161 ± 17 mmHg in placebo (n = 6; P < 0.001), baseline flow was unchanged whilst hyperaemic coronary flow was 19.89 ± 3.50 vs. 12.15 ± 0.99 ml/min per g, respectively (P < 0.01). The medial area of intramural arterioles was 1613 ± 409 with perindopril + indapamide and 8118 ± 901 µm with placebo (P < 0.001). CONCLUSION: In patients with arterial hypertension and left ventricular hypertrophy, perindopril + indapamide reduced blood pressure and left ventricular mass index and improved resting and hyperaemic myocardial blood flow. Data in rats provide evidence that the improvement in coronary flow observed after treatment is due to reverse remodelling of intramural coronary arterioles and improved microvascular function.

Effects of long-term treatment with carvedilol on myocardial blood flow in idiopathic dilated cardiomyopathy.

OBJECTIVE: To assess whether chronic treatment with carvedilol can increase myocardial blood flow (MBF) and MBF reserve in idiopathic dilated cardiomyopathy (IDC). STUDY DESIGN: In a double-blind, placebo-controlled trial, 16 consecutive patients with IDC were randomised to treatment with either carvedilol up to 25 mg twice a day (n = 8, 7 men, mean (SD) age 60 (9) years, mean (SD) left ventricular ejection fraction (LVEF) 30% (5%)), or placebo (n = 8, 6 men, mean (SD) age 62 (9) years, mean (SD) LVEF 28% (6%), NS vs carvedilol group). Before and 6 months after treatment, regional MBF was measured at rest and after intravenous injection of dipyridamole (Dip; 0.56 mg/kg in 4 min) by positron emission tomography and using (13)N-ammonia as a flow tracer. Exercise capacity was assessed as the time duration in a maximal bicycle exercise stress test. RESULTS: Carvedilol induced a significant decrease in heart rate at rest and during maximal exercise, and an increase in exercise capacity. Absolute MBF values did not significantly change after carvedilol or placebo treatment, either at rest or during Dip injection, although Dip-MBF tended to improve after treatment. Coronary flow reserve significantly increased following carvedilol treatment (from 1.67 (0.63) to 2.58 (1.04), p<0.001), whereas it remained unchanged following the placebo treatment (from 1.80 (0.84) to 1.77 (0.60), NS). Stress-induced regional perfusion defects decreased after carvedilol treatment (from 38% to 15%). CONCLUSIONS: Long-term treatment with carvedilol can significantly increase coronary flow reserve and reduce the occurrence of stress-induced perfusion defects, suggesting a favourable effect of the drug on coronary microvascular function in patients with IDC.

Baseline/post-nitrate Tc-99m tetrofosmin mismatch for the assessment of myocardial viability in patients with severe left ventricular dysfunction: comparison with baseline Tc-99m tetrofosmin scintigraphy/FDG PET imaging.

BACKGROUND: Positron emission tomography (PET) flow/metabolic mismatch is considered the nuclear medicine gold standard for the assessment of myocardial viability. The aim of this study was to investigate whether baseline/nitrate technetium 99m tetrofosmin single photon emission computed tomography (SPECT) mismatch may provide equivalent clinical information. METHODS AND RESULTS: We studied 23 patients (aged 62 +/- 10 years, 19 men) with previous myocardial infarction (16 anterior, 4 inferior, and 3 anterior plus inferior) and postischemic heart failure (gated SPECT [G-SPECT] ejection fraction, 26% +/- 8%). All patients underwent Tc-99m tetrofosmin G-SPECT at rest and after nitrates (intravenous isosorbide dinitrate, 0.2 mg/mL, 10 mL/h) as well as a fluorine 18 fluoro-2-deoxy-d-glucose (FDG) PET scan. Regional wall motion analysis was performed with quantitative G-SPECT (QGS). Myocardial dysfunction was defined as a regional QGS score of 2 or greater. Regional perfusion was assessed by quantitative perfusion score (QPS) providing percent Tc-99m tetrofosmin uptake in a 20-segment model. Semiquantitative analysis of FDG uptake was performed by use of polar maps generated by Siemens ECAT HR + software. In areas with a perfusion rate lower than 80%, PET viability was identified by a normalized FDG percent uptake/baseline Tc-99m tetrofosmin percent uptake ratio greater than 1.2. We analyzed 460 segments; 298 (64%) were dysfunctional by QGS analysis. Of these, 170 were viable by PET imaging whereas 128 were nonviable. Regional Tc-99m tetrofosmin uptake was higher in viable than in nonviable segments both at rest (60% +/- 24% vs 42% +/- 12%, P <.01) and after nitrates (67% +/- 20% vs 41% +/- 18%, P <.01). According to receiver operating characteristic curve analysis, a cutoff value of 63% for resting as well as post-nitrate G-SPECT provided the highest diagnostic accuracy for the detection of myocardial viability (67% and 72% at rest and after nitrates, respectively). When the same algorithm used for the comparison with PET (normalized nitrate percent uptake/baseline percent uptake) was applied to G-SPECT, we obtained the highest agreement with PET (accuracy, 93%; sensitivity, 95%; specificity, 92%). CONCLUSIONS: In patients with severe left ventricular dysfunction, perfusion data alone, both at rest and after nitrates, do not allow an accurate estimate of myocardial viability. In dysfunctioning segments, the analysis of rest/post-nitrate Tc-99m tetrofosmin mismatch provides results similar to those obtained by PET flow/metabolic mismatch.