Asian Cardiovasc Thorac Ann 2006;14:10-13
© 2006 Asia Publishing EXchange Ltd
Low-Prime System Minimizes Transfusions and Hemodilution in Coronary Bypass
Sven Beholz, MD,
Liling Zheng, MD,
Martin Rusche, EBCP,
Michael Kessler, EBCP,
Wolfgang Konertz, PhD
Department of Cardiovascular Surgery, Charité-University, Berlin Berlin, Germany
For reprint information contact: Sven Beholz, MD, Tel: 49 30 450 522 196, Fax: 49 30 450 522 921, Email: sven.beholz{at}charite.de, Department of Cardiovascular Surgery, Charité-University Medicine Berlin, Schumannstr. 20/21, Berlin 10117, Germany.
 |
ABSTRACT
|
|---|
Standard heart-lung machines lead to substantial hemodilution with associated impaired organ function and increased need for blood transfusions. The aim of this study was to evaluate the effect of the new PRECiSe low prime volume system on perioperative myocardial damage, hemodilution, and transfusions. In a case-matched prospective study, 40 patients undergoing coronary artery bypass surgery using PRECiSe were compared with 40 patients on a standard heart-lung machine. In the PRECiSe group, the prime volume was significantly reduced, resulting in less hemodilution and transfusion requirements during and after extracorporeal circulation: only 10% of patients needed transfusions vs. 35% in the control group, with an average transfusion need of 0.16 vs. 1.25 units. There were no significant differences in perioperative cardiac-specific enzymes. The PRECiSe system was considered safe and effective for coronary artery bypass surgery.
|
INTRODUCTION
|
|---|
Although off-pump coronary artery bypass was introduced several years ago, this procedure has not found general application due to hemodynamic instability during revascularization of the posterior wall vessels.1 Furthermore, the long-term results compared to the gold standard of coronary revascularization with extracorporeal circulation (ECC) and cardioplegic arrest, are as yet unknown. In Germany, the use of off-pump coronary artery bypass is limited to 5% to 7% of patients.2 To overcome some of the adverse effects of ECC, several low-prime systems have been introduced into clinical practice in the last 5 years. Most of these systems are configured as a closed loop consisting of a centrifugal pump, a membrane oxygenator, and a filter, connected by tubing, with the position of the drive unit beside the patient as in regular cardiopulmonary bypass (CPB). These systems, originally designed for assisted circulation in beating heart surgery, usually do not provide decompression of the heart to enable revascularization of the posterior wall in an appropriate fashion. Their use is associated with substantial loss of blood as they do not provide suckers or cardiac decompression systems. Hence, they are limited to closed-heart surgery such as isolated coronary artery bypass grafting (CABG). With the Priming Reduced Extracorporeal Circulation Setup (PRECiSe), we developed a low-prime system incorporating the new DeltaStream diagonal pump (Medos AG, Stolberg, Germany).3 This system provides all the features of regular CPB and enables full revascularization as well as open-heart procedures in a safe and simple fashion.4 The purpose of this prospective case-matched study was to investigate the use of the PRECiSe system in isolated elective CABG surgery, in terms of perioperative hemodilution and the need for transfusion of blood products.
|
PATIENTS AND METHODS
|
|---|
Eighty patients with coronary artery disease designated for isolated CABG surgery were included in the study (Table 1
); 40 patients were operated on using the PRECiSe system (PRECiSe group) and the other 40 (control group) had standard CPB. Inclusion criteria were elective primary isolated CABG and age over 18 years, exclusion criteria were prior cardiac operations with opening of the pericardium, other diseases with susceptible pericardial adhesions, preoperative circulatory instability, need for inotropics or mechanical circulatory assistance, myocardial infarction within the last 14 days, a patent foramen ovale, and any blood disorders. The patients in each group were matched with respect to age, sex, and left ventricular ejection fraction. All patients gave written informed consent to participation in the study, according to our protocol for clinical studies and to the principles of good clinical practice.5
In the PRECiSe group, the extracorporeal circulation system described in detail previously was used.3 This system consists of a closed loop of extremely short tubing connected to standard cannulae and the following components: a DeltaStream diagonal pump, a membrane oxygenator (Hilite 7000; Medos AG, Stolberg, Germany), and an arterial filter (Quart; Jostra AG, Hirrlingen, Germany). Parallel to this closed loop, a hardshell reservoir was connected to the inlet and outlet of the diagonal pump to maintain quick cardiac decompression and enable the use of suckers and vents to reduce blood loss during surgery. The system was primed and de-aired with crystalloid solution; autologous priming was maintained depending on the hemodynamics. Only the amount of prime delivered to the patient was registered as the final priming volume.
In the control group, the standard ECC setup consisted of the same components except that a Jostra Rotaflow pump (Jostra AG, Hirrlingen, Germany) was used. Priming consisted of 1,500 mL modified crystalloid prime, and 2.5 million units of aprotinin were added. No autologous priming was used in this group as this is not part of our routine perfusion protocol. In both groups, the activated clotting time was maintained between 450 and 500 sec during ECC; after termination of ECC and removal of the cannula, full reversal with protamine was performed. In both groups, perfusion was maintained at a mean flow of 2.4 to 2.8 L·min–1·m–2 with a temperature range of 35°C to 36°C. During ECC volume management, standard CPB was carried out by flow control and, if necessary, with small amounts of vasopressors (noradrenaline). To achieve adequate flow in the PRECiSe group, small amounts of fluid were added to the circulation from the reservoir to prevent the inferior vena cava from collapsing around the venous return cannula and to avoid the danger of air emboli. Warm antegrade blood cardioplegia was applied intermittently to the aortic root in both groups.6 Cell savers were not used in either group. Pre-, intra- and postoperative substitution of volume was performed using crystalloid solution or 6% hydroxyethyl starch. One unit of packed red blood cells was given if the hematocrit dropped below 25% after institution of anesthesia, 20% during ECC, 25% in the first 24 h, or 28% before discharge. Prior to addition of packed red blood cells, a red blood cell count was undertaken again, and the same transfusion criteria were applied. Blood pressure was maintained by a flow of 2.4 – 2.8 L·min–1·m–2. If mean blood pressure dropped below 50 mm Hg, small amounts of noradrenaline were applied. Fluid management during institution of anesthesia, CPB, and the first 2 postoperative days was monitored, including fluid balance, crystalloid and colloidal substitution, and transfusions of blood components as well as the final prime, as described above. Hematocrit, creatine kinase (CK) and CK-MB were obtained preoperatively, after the institution of anesthesia, at the start and end of ECC, at the end of the operation, at 6, 24, and 48 h after the end of the operation, and at discharge. Predicted mortality was calculated by the logistic EuroSCORE.7
Data were expressed as mean ± standard deviation. For statistical analysis, the Mann-Whitney U test was used. A p-value below 0.05 was considered significant.
|
RESULTS
|
|---|
There was an uneventful course of perfusion in all patients in both groups. In addition to the matching criteria of age, sex, and ejection fraction, both groups were comparable in body surface area, duration of perfusion and ischemia, completeness of revascularization, and use of the left internal thoracic artery to revascularize the left anterior descending artery (Table 1
). There were no myocardial infarctions or major adverse events; observed mortality was below predicted mortality according to the logistic EuroSCORE in both groups.
The final prime volume applied to the patient was 1,506.3 ± 58.5 mL in the control group and 257.1 ± 146.5 mL in the PRECiSe group ( p < 0.05). After similar preoperative hematocrit levels in the PRECiSe group (40.5% ± 3.5 %) and controls (40.2% ± 2.8%), there was a drop in both groups at the beginning of ECC (Figure 1). In the control group, the hematocrit was significantly less than in the PRECiSe group during ECC, and remained significantly reduced until discharge. Freedom from transfusion of red blood cells during hospital stay was 65% in the control group and 90% in the PRECiSe group. One patient in the PRECiSe group received one unit intraoperatively and 3 patients had 1 – 2 units postoperatively. In contrast, 8 patients in the control group received 1 – 3 units of red blood cells intraoperatively ( p < 0.05) and 7 patients had 2 – 6 units postoperatively ( p < 0.05; Figure 2). There was no transfusion of fresh frozen plasma or platelets in either group. Mean chest tube drainage was 373 ± 119 mL in the PRECiSe group and 501 ± 272 mL in the control group ( p < 0.01). There was no significant difference in the CK or CK-MB perioperatively (Figures 3 and 4).
View larger version (13K):
[in this window]
[in a new window]
|
Figure 1. Perioperative changes in hematocrit (mean ± standard deviation). ECC = extracorporeal circulation. *p < 0.05
|
|
|
DISCUSSION
|
|---|
After the introduction of CPB by Gibbon8 in the early 1950s, ECC rapidly became available for open heart procedures. To reduce the need for foreign blood in the prime, crystalloid prime became the standard in adult cardiac surgery.9 As the volume of crystalloid prime delivered to the patient at the beginning of ECC is 1.5 to 2.5 L, CPB nowadays is associated with significant hemodilution. In normothermic as well as hypothermic settings, this hemodilution may cause adverse effects such as impairment of liver and renal function.10,11 A low hematocrit during ECC may also lead to postoperative myocardial depression, resulting in increased need for inotropics.12 Finally, extreme hemodilution may lead to coagulation disorders, resulting in increased postoperative blood loss, and thus increased postoperative transfusion.13 To avoid extreme hemodilution, transfusion of 0.5 to 1.4 units of red blood cells, depending on the type of operation, remains routine in German cardiac centers.14 In a recent review, the rate of transfusion, even in off-pump CABG, was determined to be 18% to 28% compared to 29% to 49% in control groups using a standard heart-lung machine.15
Reduced-prime CPB setups, originally designed for assisted circulation in beating heart CABG surgery, have proven to reduce the inflammatory response by their closed loop that avoids blood-air contact.16 However, they have failed to reduce the need for perioperative transfusion as they do not provide the possibility of returning mediastinal shed blood directly to the circulation.17 In addition, a closed loop limits the ability for rapid and effective decompression of the heart by returning blood to a reservoir, resulting in increased central venous pressure if the full heart is tilted up. Revascularization of the posterior wall vessels may be limited in these situations.
The PRECiSe system was designed to overcome the adverse effects of conventional reduced-prime systems; in a recent study, the safe and effective use in elective CABG surgery was demonstrated.4 In this first case-matched clinical trial, a substantial reduction of transfusion rate and amount compared to standard ECC setups was demonstrated, as well as safe perfusion and complete revascularization. Using the PRECiSe system, patients could be operated on without myocardial damage, as demonstrated by CK and CK-MB levels. Further studies are needed to investigate the safe and effective use of the PRECiSe system in valvular and combined surgical procedures.
Presented at the 12th Annual Meeting of the Asian Society for Cardiovascular Surgery, Istanbul, Turkey, April 19 – 22, 2004.
|
REFERENCES
|
|---|
- Benetti FJ, Naselli G, Wood M, Geffner L. Direct myocardial revascularization without extracorporeal circulation. Experience in 700 patients. Chest 1991;100:312–6.[Abstract/Free Full Text]
- Kalmar P, Irrgang E; German Society for Thoracic and Cardiovascular Surgery. Cardiac surgery in Germany during 2002: a report by German Society for Thoracic and Cardiovascular Surgery. Thorac Cardiovasc Surg 2003;51:25–9.[Medline]
- Beholz S, Kessler M, Thölke R, Konertz WF. Priming Reduced Extracorporeal Circulation Setup (PRECiSe) with the DeltaStream diagonal pump. Artif Organs 2003;27:1110–5.[Medline]
- Beholz S, Kessler M, Konertz WF. PRECiSe (priming reduced extracorporeal circulation setup): results of a safety study. Heart Surg Forum 2003;6:311–5.[Medline]
- Beholz S, Koch C, Konertz W. Quality management system of a university cardiac surgery department according to DIN EN ISO 9001:2000. Thorac Cardiovasc Surg 2003;51:167–73.[Medline]
- Calafiore AM, Teodori G, Mezzetti A, Bosco G, Verna AM, Di Giammarco G, et al. Intermittent antegrade warm blood cardioplegia. Ann Thorac Surg 1995;59:398–402.[Abstract/Free Full Text]
- Roques F, Nashef SA, Michel P, Gauducheau E, de Vincentiis C, Baudet E, et al. Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients. Eur J Cardiothorac Surg 1999;15:816–23.[Abstract/Free Full Text]
- Gibbon JH Jr. Application of a mechanical heart and lung apparatus to cardiac surgery. Minn Med 1954;37:171–85.[Medline]
- Perasalo O, Siltanen P, Merikallio E. Use of hemodilution in total body perfusion. J Cardiovasc Surg (Torino) 1967;8:442–5.[Medline]
- Swaminathan M, Phillips-Bute BG, Conlon PJ, Smith PK, Newman MF, Stafford-Smith M. The association of lowest hematocrit during cardiopulmonary bypass with acute renal injury after coronary artery bypass surgery. Ann Thorac Surg 2003;76:784–92.[Abstract/Free Full Text]
- Nollert G, Sperling J, Sakamoto T, Jaeger BR, Jonas RA. Higher hematocrit improves liver blood flow and metabolism during cardiopulmonary bypass in piglets. Thorac Cardiovasc Surg 2001;49:226–30.[Medline]
- Fang WC, Helm RE, Krieger KH, Rosengart TK, DuBois WJ, Sason C, et al. Impact of minimum hematocrit during cardiopulmonary bypass on mortality in patients undergoing coronary artery surgery. Circulation 1997;96(9 Suppl):II194–9.
- Hardy JF, Martineau R, Couturier A, Belisle S, Cartier R, Carrier M. Influence of haemoglobin concentration after extracorporeal circulation on mortality and morbidity in patients undergoing cardiac surgery. Br J Anaesth 1998;81(Suppl 1):38–45.[Free Full Text]
- Dietrich W, Luth JU, Kormann J, Wick S, Kaiser W, Eberle B, et al. Intraoperative blood requirements and allogeneic blood transfusion in cardioanesthesia. Data analysis of 7729 patients in 12 cardiac surgical clinics. Anaesthesist 1999;48:876–83.[Medline]
- Mack MJ. Advances in the treatment of coronary artery disease. Ann Thorac Surg 2003;76:S2240–5.[Abstract/Free Full Text]
- Fromes Y, Gaillard D, Ponzio O, Chauffert M, Gerhardt MF, Deleuze P, et al. Reduction of the inflammatory response following coronary bypass grafting with total minimal extracorporeal circulation. Eur J Cardiothorac Surg 2002;22:527–33.[Abstract/Free Full Text]
- Folliguet TA, Villa E, Vandeneyden F, Laborde F. Coronary artery bypass graft with minimal extracorporeal circulation. Heart Surg Forum 2003;6:297–301[Medline]
TOP
ABSTRACT
INTRODUCTION
