Perfusion

Cardiac power output has been shown to quantify cardiac reserve. Cardiac reserve is defined as the difference between basal and maximal cardiac performance. We compared cardiac power index to other commonly used hemodynamic parameters to validate its usefulness to stage heart failure patients and determine the optimal time for implantation of mechanical circulatory support. A retrospective study of twenty-eight heart failure patients implanted with mechanical circulatory support was analyzed at three levels of drug therapy. Subjects were further separated into two categories: survived versus deceased. Cardiac power index was the only statistically significant hemodynamic parameter that identified cardiac reserve (p<0.05) in this patient population. These results showed that a cardiac power index at or below 0.34 Watts/m2 resulted in increased mortality rate, ninety days post-implantation.

This study compared four pediatric cardiopulmonary bypass (CPB) circuits with four different hollow-fiber membrane oxygenators and their specific reservoirs, Capiox RX15, Quadrox-i pediatric, Quadrox-i pediatric with integrated arterial filter (IAF) and KIDS D101, in a simulated CPB circuit identical to that used in the clinical setting at our institution to test their ability to maintain hemodynamic properties, remove gaseous microemboli (GME), and to test the amount of blood “stolen” by the arterial filter purge line. The circuit was first primed with Ringer’s Lactate solution, then red blood cells were added and the hematocrit was maintained at 30%. A 5-cc bolus of air was injected just proximal to the venous reservoir over a thirty-second interval and GME were monitored using an Emboli Detection and Classification quantifier. Transducers were placed at pre-oxygenator, post-oxygenator and distal arterial line (post-filter) positions. Flow probes were also placed both pre and post filter. The injections were made at three flow rates, hypothermic and normothermic temperatures, and with the purge line in both the opened and closed positions. Six injections were done at each of the 12 experimental conditions. Results demonstrated that GME in the arterial line increased with increasing temperature and flow rate. The Capiox RX15 had the least GME in the arterial line at all experimental conditions. The KIDS D101 had the largest pressure drop and the lowest retention of hemodynamic energy, while the Capiox had the lowest pressure drop. All of the oxygenators had a similar amount of “stolen” blood flow and it was consistently under 10% of the total flow reaching the patient.

This extension study investigated the association between preoperative cerebral blood flow (CBF) velocity and postoperative cognitive decline (POCD) at a three-month follow-up in patients who underwent cardiac surgery. Continuous transcranial Doppler ultrasound on both middle cerebral arteries (MCAs) was used preoperatively in 31 right-handed cardiac surgery patients at rest. Each patient performed a neuropsychological evaluation to assess cognitive performance before surgery, at discharge and at three-month follow-up. Patients with POCD at the three-month follow-up had a marginally significantly lower preoperative CBF velocity in the left MCA than patients without POCD. Moreover, the group with POCD had a significantly lower CBF velocity in the left than in the right MCA, whereas no difference between the left and right CBF velocity was found in the group without POCD. These preliminary findings suggest that reduced preoperative CBF velocity in the left MCA may represent an independent risk factor for cognitive decline in patients three months after surgery.

Surgical repair of transverse aortic arch aneurysms frequently employ hypothermia and antegrade cerebral perfusion as protective strategies during circulatory arrest. However, prolonged mesenteric and lower limb ischemia can lead to significant lactic acidosis and end organ dysfunction, which remains a significant cause of post-operative morbidity and mortality. We report our experience with additive warm mesenteric and lower body perfusion (1-3 L/min, 30°C) in addition to continuous cerebral and myocardial perfusion in 5 patients who underwent total aortic arch replacement with trifurcated head vessel re-implantation and distal elephant trunk reconstruction. Concomitant surgical procedures included re-operations (2), aortic root operations (2), coronary artery bypass (2) and descending thoracic aortic replacement (1). Serum lactate levels demonstrated a rapid decline from a peak 9.9±2.6 post circulatory arrest to 3.4±2.0 in the intensive care unit (ICU). The lowest serum bicarbonate levels were 19.3±3.5 mmol/L, intra-operatively, which normalized to 28.4±2.4 mmol/L on return to the ICU. The lowest pH levels were 7.25±0.10, corrected to 7.43±0.04 on return to the ICU. Mean cardiopulmonary bypass and aortic cross-clamp times were 361±104 and 253±85 minutes, respectively. Mean cerebral and lower body circulatory arrest times were 0 (0) and 50±35 minutes, respectively. The mean time required for systemic rewarming was 95±66 minutes. There were no in-hospital mortalities and no patient experienced any neurological, mesenteric, renal or lower limb ischemic complications. Two patients required mechanical ventilation >24 hours, and one patient returned for reoperation for bleeding. Median intensive care unit and total hospital lengths of stay were 5 and 16 days, respectively. Our results suggest early serum lactate clearance, normalization of acidosis, and metabolic recovery when utilizing a simultaneous cerebral perfusion and warm body protection strategy for complex aortic arch surgery. This additive perfusion strategy may attenuate visceral and lower body ischemia that normally develops during periods of deep hypothermic circulatory arrest.

Objective(s): Determine the thresholds of procalcitonin (PCT) and N-terminal pro-B-type natriuretic peptide (Nt-pro-BNP) associated with poor prognosis after heart surgery with CPB. Design: Prospective observational study. Setting: Academic Medical Center Habib Bourguiba. Participants: Adult patients consecutively operated for coronary or valve surgery with CPB, elective or semi-urgent. Interventions: Serum concentrations of PCT and Nt-pro-BNP were determined before and after CPB, in the fourth postoperative hour (H4) and every day during the first 4 days. Receiver-operating characteristic curves and cut-off values were used to assess the ability of these markers to predict length of intensive care unit (ICU) stay >3 days. Measurements and Main Results: Forty patients were included in the study. Systemic inflammatory response syndrome (SIRS) occurred in 35 (87.5%) patients. Seventeen of them (42.5%) showed severe SIRS. Significantly higher serum concentrations of Nt-pro-BNP and PCT were found in patients with severe SIRS. Receiver operating characteristic (ROC) analysis showed that the threshold of PCT was 0.737 ng/mL and that of Nt-pro-BNP was 1235 pg/mL on day 1 could predict an ICU stay of more than 3 days. The association of Nt-pro-BNP to procalcitonin (p=0.009) better predicted the ICU stay than PCT alone (p=0.02) or Nt-pro-BNP alone (p=0.03). The best combination is Nt-pro-BNP + PCT + C-reactive protein (CRP) (p=0.007). Conclusions: PCT and Nt-pro-BNP on day 1 may be associated with severe SIRS and predict the length of stay. A biomarker approach combining PCT, CRP and BNP is superior to a traditional single marker for predicting ICU stay.

Intimal hyperplasia is the leading cause of long-term failure in coronary artery bypass vein grafting, coronary artery stenting, angioplasty, arteriovenous fistula for dialysis, and allograft transplantation. Intimal hyperplasia is a product of vascular smooth muscle cell proliferation, migration through the internal elastic lamina, and deposition of extracellular matrix proteins driven by growth factors in the vasculature. This vascular pathology results in a progressive diminution of the vessel lumen and serves as a site for thrombosis and atherosclerotic lesions. A key cell type in the initiation of intimal hyperplasia is the vascular endothelial cell, which appears to have down-stream effects on the vascular smooth muscle proliferation and migration. Currently, the only means available for prevention of intimal hyperplasia is through inhibition of mammalian target of rapamycin (mTOR) with the immunosuppressant rapamycin. mTOR integrates up-stream signals from growth factors such as IL-2 and senses the cellular nutrient and energy levels and redox status. This presentation will discuss the potential means of preserving the vascular endothelial cell and, thereby, reducing the development of intimal hyperplasia in our open-heart surgical patients.

Background: Numerous cardiopulmonary bypass circuits with various coatings designed to reduce the inflammatory response and to provide better hemocompatibility are available. The aim of this study was to compare the effect of phosphorylcholine-coated, albumin-heparin-coated and synthetic polymer-coated perfusion tubing systems on patient outcome. Methods: We performed a retrospective database review of elective patients between January 1st 2010 and December 31st 2010. Demographics, preoperative, operative, postoperative data and follow-up were collected and statistically analysed. Results: We identified 201 patients and formed three groups: Group 1 with phosphorylcholine coating (n=133), Group 2 with albumin-heparin coating (n=32) and Group 3 synthetic polymer coating (n=36). Mean age was 68±11years, additive Euroscore 5.8±2.7. In-hospital outcomes were comparable between the groups without statistically significant differences. The overall 30-day and 1-year late survival were 98.5% and 96.7±1.9%, respectively. Conclusions: Our findings suggest that in-hospital and follow-up outcomes are comparable in cardiac surgery patients after using either phosphorylcholine-coated, albumin-heparin-coated or synthetic polymer-coated circuits during cardiopulmonary bypass.

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) has been indicated in patients with severe refractory respiratory failure from various causes for more than 30 years, even for the small infant.¹ Improved outcome from using ECMO for respiratory failure has been reported worldwide, ranging from 15% to over 50% in recent reviews.^1,2 The rationale of this therapy is to allow time for the lungs to heal, minimizing further lung injury from positive pressure ventilation.^3,4 We describe a case of severe acute respiratory distress syndrome (ARDS) with extensive barotrauma supported by VV-ECMO for 96 days in a resource-limited center. This is likely the longest ECMO support ever reported in a child.

Atrial septal defect is a common form of congenital heart disease. Percutenous closure is an important treatment option for these patients. In this case series, we intend to share the percutaneous closure of the difficult types of secundum atrial septal defects.