Functional recovery of diabetic mouse hearts by glutaredoxin-1 gene therapy: role of Akt-FoxO-signaling network.

Recent studies suggest that glutaredoxin-1 (Glrx-1) may serve as therapeutic target for diabetic hearts. As the level of reactive oxygen species (ROS) is increased in the pathologic hearts including ischemia/reperfusion (I/R) and diabetes, we assumed that upregulation of Glrx-1 could reduce the cardiac risk factors associated with I/R and/or diabetes. Diabetes was induced in mice by i.p. injection of streptozotocin (150 mg kg(-1)). Eight days after when the blood glucose was elevated to 400 mg per 100 ml, the animals were randomly assigned to one of the following three groups, which received either empty vector, or LacZ or Glrx-1 adenoviral construct. Four days later, isolated working hearts were subjected to 30 min ischemia followed by 2 h reperfusion. Glrx-1 gene therapy significantly enhanced the Glrx-1 level, which prevented I/R-mediated reduction of ventricular recovery, increased myocardial infarct size and cardiomyocyte apoptosis in diabetic myocardium. In concert, Glrx-1 prevented diabetes and ischemia-reperfusion induced reduction of cardioprotective proteins including Akt, FoxO-1, and hemeoxygenase-1, and abolished the death signal triggered by Jnk, p38 mitogen-activated protein kinase, and c-Src. Glrx-1 gene therapy seems to prevent cardiac complications in diabetic heart due to the I/R by switching the death signal into survival signal by activating Akt-FoxO-signaling network.

Role of STAT3 in ischemic preconditioning.

We recently demonstrated that ischemic preconditioning (IPC) induced by cyclic episodes of short durations of ischemia and reperfusion potentiates a signal transduction cascade involving protein tyrosine kinases and MAP kinases. A rapid activation of janus kinase (JAK) and several signal transducers and activators of the transcription (STATs) including STAT3, STAT5A and STAT6 has been shown to occur during myocardial ischemia and reperfusion. This study sought to examine if JAK/STAT signaling pathway play any role in classical early phase of IPC. Isolated working rat hearts were perfused for 15 min with KHB buffer in the absence or presence of a JAK kinase inhibitor tyrphostin AG490 (5 microm) followed by IPC, 30 min global ischemia and 2 h of reperfusion. The results demonstrated extensive phosphorylation of JAK2 and STAT3 in the IPC hearts which was almost completely abolished by an inhibitor of JAK2, AG490. IPC displayed cardioprotection as evidenced by improved post-ischemic contractile recovery, decreased myocardial infarct size and reduced number of apoptotic cardiomyocytes. AG490 blocked IPC-mediated cardioprotection by altering the IPC-mediated survival signal into death signal. Thus, IPC-induced upregulation of antiapoptotic gene bcl-2 and downregulation of pro-apoptotic gene bax are decreased and increased, respectively, in the AG490 treated hearts. The results suggest that early phase of IPC potentiates JAK/STAT signaling by activating STAT3 which transmits a survival signal to the myocardium.

Does warm blood retrograde cardioplegia preserve right ventricular function?

BACKGROUND: Efficacy of warm blood retrograde cardioplegia in preserving right heart function remains controversial. The current study was conducted to gauge the preservation of right ventricular function after warm blood retrograde cardioplegia. METHODS: We studied 75 consecutive patients undergoing isolated heart valve procedures with warm blood retrograde cardioplegia as the exclusive mode of preservation. Right ventricular radionuclide ejection fraction and hemodynamic measurements using a pulmonary artery catheter were calculated before and within 3 days after operation. RESULTS: Postoperative radionuclide right ventricular ejection fraction was well preserved at 0.4686 +/- 0.0122 compared with 0.4327 +/- 0.0255 preoperatively (p = 0.7064). Right ventricular systolic work index improved from 5.82 +/- 0.52 to 8.97 +/- 0.60 g x m/m2 (p < 0.0001) and cardiac index increased from 2.40 +/- 0.09 to 2.92 +/- 0.11 L/m2 (p < 0.0001). When right ventricular systolic work index was correlated with preload, 30 patients moved up and down on the same ventricular function curve and 42 moved to a higher inotropic curve postoperatively. Only 3 patients demonstrated decreased inotropy. CONCLUSIONS: In the clinical setting warm blood retrograde cardioplegia used as the exclusive mode of myocardial preservation provides adequate protection of the right heart.

Does cardioplegia type affect outcome and survival in patients with advanced left ventricular dysfunction? Results from the CABG Patch Trial.

BACKGROUND: There is controversy regarding which cardioplegic solution, temperature, and route of administration provides superior protection. The CABG Patch Trial enrolled a high-risk group of coronary artery disease patients with an ejection fraction of <36%. Thus, they constitute an ideal group to benefit most from optimal cardioplegic protection. METHODS AND RESULTS: All patients randomized into the trial were compared with respect to the use of blood and crystalloid cardioplegia. In addition, a questionnaire was sent to surgeons requesting blood cardioplegic temperature and route. Patients receiving crystalloid cardioplegia versus those receiving blood cardioplegia were found to have significantly more operative deaths (2% versus 0.3%, P:=0.02), postoperative myocardial infarctions (10% versus 2%, P:<0.001), shock (13% versus 7%, P:=0. 013), and postoperative conduction defects (21.6% versus 12.4%, P:=0. 001). Despite this, early death (6% crystalloid versus 4% blood cardioplegia) and late death (24% crystalloid versus 21% blood cardioplegia) statistics were not significantly different. Patients receiving normothermic blood had less postoperative right ventricular dysfunction (10%) than did patients receiving cold blood (25%) or cold blood with warm reperfusion (30%) (P:=0.004). There was no significant difference in early or late death. Finally, patients who received combined antegrade and retrograde cardioplegia had significantly less inotrope use (71% versus 84%, P:=0.002), right ventricular dysfunction (23% versus 41%, P:=0.001), and postoperative balloon pump use (12% versus 19%, P:=0.02) than did those who received antegrade cardioplegia. There was no difference in survival. CONCLUSIONS: Blood cardioplegia and combined antegrade and retrograde cardioplegia are superior to crystalloid and antegrade cardioplegia alone for postoperative morbidity. Despite this, there is no significant difference in early or late survival.

Myocardial protection by preconditioning of heart with losartan, an angiotensin II type 1-receptor blocker: implication of bradykinin-dependent and bradykinin-independent mechanisms.

BACKGROUND: Ischemic preconditioning (PC) represents a state-of-the-art technique for myocardial preservation. Although certain intracellular mediators have been shown to play a role in PC, the exact nature of the trigger for PC is not known. Our previous study demonstrated that intracellular bradykinin released from the heart during ischemia/reperfusion plays a role in myocardial preservation. This study was undertaken to further examine the mechanism of bradykinin-mediated PC. METHODS AND RESULTS: Since the bradykinin B(2) receptor is likely to provide cardioprotection by blocking angiotensin II formation, we determined the effects of an angiotensin II type 1 (AT(1)) receptor blocker, losartan, and a bradykinin B(2) receptor blocker, HOE 140, on myocardial protection. Isolated rat hearts were perfused initially by the Langendorff mode with Krebs-Henseleit buffer (KHB) for 15 minutes in the absence (control) or presence of losartan (4.5 micromol/L) and/or HOE 140 (10 micromol/L). After conversion to the working mode for 10 minutes (baseline), randomly assigned control and experimental hearts were subjected to 30 minutes of normothermic global ischemia followed by 2 hours of reperfusion. Myocardial function, infarct size, cardiomyocyte apoptosis, and amount of bradykinin/angiotensin released from the hearts were measured at baseline and during reperfusion while in the working mode. Significant postischemic ventricular recovery was demonstrated by improved developed pressure and aortic flow and reduced myocardial infarct size and apoptotic cell death with losartan, whereas the reverse was true for HOE 140. The functional recovery and infarct size-lowering ability of losartan were partially blocked and the antiapoptotic function of losartan was completely blocked by HOE 140. CONCLUSIONS: The results document that losartan reduced whereas HOE 140 increased myocardial ischemia/reperfusion injury by blocking AT(1) and bradykinin B(2) receptors, respectively, suggesting a role of the bradykinin B(2) receptor in PC. Losartan provided cardioprotection through both bradykinin-dependent and bradykinin-independent mechanisms.

Preconditioning of swine heart with monophosphoryl lipid A improves myocardial preservation.

BACKGROUND: Ischemic preconditioning has been proven to be a powerful tool for myocardial protection in the setting of ischemia and reperfusion. A new drug to provide pharmacologic preconditioning, monophosphoryl lipid A (MLA), was administered 24 hours before an acute coronary occlusion in pigs to determine the effect on pharmacologic preconditioning. METHODS: Two studies were completed. In the first, swine were distributed into five groups: group I, control; group II,. aminoguanidine (AMG) (30 mg/kg), a selective inducible nitric oxide synthase (iNOS) blocker; group III, MLA (10 microg/kg); group IV, MLA (35 microg/kg); and group V, MLA and AMG (35 microg/kg and 30 mg/kg, respectively). Twenty-four hours after administration of the MLA, AMG, or both, regional left anterior descending coronary artery ischemia was induced for 15 minutes followed by one hour of global normothermic cardioplegic arrest and three hour reperfusion. Left ventricular function, tissue injury, and percentage of myocardial infarction were measured. Left ventricular myocardium in the left anterior descending coronary artery region was sampled for iNOS messenger RNA (mRNA) during ischemia and reperfusion. In the second study, pigs were sacrificed 0, 4, 6, 8, and 24 hrs after MLA/AMG administration for iNOS mRNA determination in nonischemic myocardium. RESULTS: Use of MLA significantly improved postischemic ventricular function, and reduced creatinine kinase release and percentage of infarction. Monophosphoryl lipid A induced expression of iNOS mRNA in nonischemic myocardium within four hours of administration which returned to base line by 24 hours. Normothermic regional ischemia then induced expression of iNOS mRNA, which returned to base line during reperfusion. Aminoguanidine completely abolished both MLA-induced and ischemia-induced iNOS mRNA and blocked the beneficial effects of MLA. CONCLUSIONS: Use of MLA can provide myocardial preservation through enhanced expression of iNOS mRNA.

Dietary coenzyme Q(10) supplement renders swine hearts resistant to ischemia-reperfusion injury.

To examine whether nutritional supplementation of coenzyme Q(10) (CoQ(10)) can reduce myocardial ischemia-reperfusion injury, a group of swine was fed a regular diet supplemented with CoQ(10) (5 mg x kg(-1) x day(-1)) for 30 days. Another group of pigs that were fed a regular diet supplemented with placebo served as a control. After 30 days, isolated in situ pig hearts were prepared and hearts were perfused with a cardiopulmonary pump system. Each heart was subjected to 15 min of regional ischemia by snaring of the left anterior descending coronary artery, followed by 60 min of hypothermic cardioplegic global ischemia and 120 min of reperfusion. After the experiments were completed, myocardial infarct size was measured by triphenyltrazolium chloride staining methods. Postischemic left ventricular contractile function was better recovered in the CoQ(10) group than in the control group of pigs. CoQ(10)-fed pigs revealed less myocardial infarction and less creatine kinase release from the coronary effluent compared with control pigs. The experimental group also demonstrated a smaller amount of malonaldehyde in the coronary effluent and a higher content of the endogenous antioxidants ascorbate and thiol. Significant induction of the expression of ubiquitin mRNA was also found in the hearts of the CoQ(10)-fed group. The results of this study demonstrate that nutritional supplementation of CoQ(10) renders the hearts resistant to ischemia-reperfusion injury, probably by reducing the oxidative stress.

Risk of dysphagia after transesophageal echocardiography during cardiac operations.

BACKGROUND: Dysphagia can be a significant complication following cardiac operations. This study evaluates its incidence and relationship to intraoperative transesophageal echocardiography (TEE) for specific indications versus known factors such as stroke or prolonged intubation. METHODS: Records of 838 consecutive cardiac surgical patients were reviewed, and categorized into those who received TEE for specific indications versus those who did not (nonTEE). Dysphagia was recorded when symptoms were confirmed by barium cineradiography. Multiple logistic regression identified significant factors causing dysphagia. RESULTS: TEE was significantly related to the development of postoperative dysphagia by multiple logistic regression (p < 0.001). After controlling for other significant factors (stroke, left ventricular ejection fraction, intubation time, duration of operation), the odds of dysphagia for TEE patients was 7.8 times greater than for nonTEE patients. CONCLUSIONS: TEE may be an independent risk factor for dysphagia following cardiac operations.

Myocardial protection with red wine extract.

Cardioprotective action of red wine was studied by preperfusing isolated rat hearts with ethanol-free red wine extract for 15 min before subjecting them to 30 min of global ischemia followed by 2 h of reperfusion. Four other group of rats were studied under identical conditions, of which one served as control; one was treated with 10 microM trans-resveratrol (RVT), one of the major antioxidants found in red wines; another, with 0.07% ethanol; and another, with 0.07% ethanol plus 10 microM RVT. The results of our study demonstrated that both red wine extract and RVT were equally cardioprotective, as evidenced by their abilities to improve postischemic ventricular functions including developed pressure and aortic flow. Developed pressure values at 60 min after reperfusion were 81.8 +/- 1.2 and 68.8 +/- 4.1 mm Hg for the red wine extract and RVT groups, respectively, versus 49.7 +/- 2.7 mm Hg for the control group. These compounds also reduced myocardial infarct size compared with the control hearts (20.1 +/- 0.5% and 10.5 +/- 0.3% for red wine extract and RVT groups, respectively, vs. 29.9 +/- 3.1% for the control group). The ethanol-treated group displayed slightly better functional recovery, which deteriorated sharply toward the end of the reperfusion period, and the extent of infarction was comparable to that of the control group (31.5 +/- 0.9%). In the ethanol plus RVT group, postischemic contractile function was significantly better than control, and infarct size also was reduced to 20.9 +/- 0.7%. The amount of malonaldehyde formation in the postischemic myocardium was reduced by red wine extract and RVT, indicating a reduction of oxidative stress developed in the ischemic reperfused myocardium. In vitro studies revealed that red wine extract is a potent antioxidant as evidenced by its ability to scavenge peroxyl radical in vitro. Taken together, the results of our study indicate that red wines are cardioprotective by their ability to function as an in vivo antioxidant.

Targeted disruption of the mouse Sod I gene makes the hearts vulnerable to ischemic reperfusion injury.

The role of Cu/Zn-superoxide dismutase (SOD) in myocardial ischemic reperfusion injury was studied by using a mouse model with targeted disruption of the mouse Sod I gene. Inactivation of the functional mouse Sod I gene in hearts by gene targeting (Sod I(+/-)) resulted in a 50% reduction of Cu/Zn-SOD mRNA and significant reduction of Cu/Zn-SOD enzyme activity compared with that of wild-type Sod I(+/+) mice. Cu/Zn-SOD mRNA could not be detected in Sod I(-/-) heart. The isolated buffer-perfused hearts from the knockout mice devoid of any functional copy of the Sod I (Sod I(-/-)) and matched nontransgenic control mice were subjected to 30 minutes of global ischemia followed by 2 hours of reperfusion. For both groups of mice, the postischemic functional recovery for the hearts was lower than the baseline, but the recovery for the Sod I(-/-) was less compared with the wild-type mice. Thus, the postischemic recovery of the developed force and the maximum first derivative of the developed force were consistently lower for the Sod I(-/-) mouse hearts compared with wild-type control hearts. The coronary flow was lower compared with the baseline levels for both groups of hearts, but there was no significant difference between the groups. The myocardial infarction determined from the ratio of infarct size/area of risk was higher for the Sod I(-/-) mice compared with the control mice. The amount of creatine kinase release from the wild-type mouse hearts was less compared with the Sod I(-/-) mouse hearts. In concert, a reduced amount of oxidative stress was found in the hearts of wild-type mice compared with Sod I(-/-) mouse hearts. These results documented that Sod I(-/-) mouse hearts were more susceptible to ischemic reperfusion injury compared with corresponding wild-type mouse hearts, suggesting that the Sod I gene constitutes an important defense element for the hearts.

Is there a relationship between systemic perfusion temperature during coronary artery bypass grafting and extent of intraoperative ischemic central nervous system injury?

OBJECTIVE: This study was designed to compare the volume of cerebral infarction in patients operated on under either hypothermic or tepid/normothermic perfusion for coronary revascularization. METHODS: A randomized trial with preoperative, postoperative, and late neurologic evaluation was conducted in patients undergoing coronary revascularization having either hypothermic or tepid/normothermic perfusion for coronary revascularization. The goal was to determine whether perfusion temperature correlated with neurologic dysfunction associated with coronary artery bypass. RESULTS: Twelve intraoperative ischemic strokes occurred during coronary revascularization in a series of 291 patients. Six of these were in the group receiving hypothermic perfusion and 6 in groups receiving the tepid/normothermic perfusion. Measuring the infarct volume documented that 3 of the strokes in each group resulted in minor or small infarcts and 3 in each group were significant, major strokes. The volume of infarction, whether including all 6 patients in each group or only those with major strokes, was no different between the hypothermic and the tepid/normothermic groups. CONCLUSIONS: In this series of 291 patients randomized to perfusion temperature, we observed no relationship between the size of a cerebral ischemic infarct and the perfusate temperature during coronary revascularization.

Molecular targets of gene therapy.

Ischemic reperfused heart represents a potential target for gene therapy because gene transfer can represent an alternate pharmacological approach to protect the heart from cellular injury. Gene therapy may be particularly useful to deal with previously unapproachable problems. For myocardial preservation, gene therapy could replace those pharmacological interventions when drugs are delivered locally by sustained release with the help of mechanical device, eg, implants. In this review, attempts are made to define the molecular targets for gene therapy primarily applicable to myocardial preservation associated with ischemia and reperfusion. It has been emphasized that for successful gene transfer, not only characterization of proper targets and elimination of undesirable side effects are necessary, but also the therapy must be proven superior compared to other pharmacological interventions including surgery.

Ischemic preconditioning reduces apoptosis by upregulating anti-death gene Bcl-2.

BACKGROUND: Reperfusion of ischemic myocardium causes cardiomyocyte apoptosis in concert with downregulation of Bcl-2 gene. Ischemic preconditioning (PC) mediated by cyclic episodes of short-term ischemia and reperfusion reduces apoptotic cell death. PC also triggers a signaling pathway by potentiating tyrosine kinase phosphorylation leading to the activation of p38 MAP kinase and MAPKAP kinase 2. The nuclear transcription factor, NFkappaB, plays a crucial role in this signaling process. Because NFkappaB is a target of oxygen free radicals and Bcl-2 is an antioxidant gene, we hypothesized that reactive oxygen species might play a role in the signaling process. METHODS AND RESULTS: Isolated rat hearts were perfused in the absence or presence of either dimethyl thiourea (DMTU), a hydroxyl radical scavenger, or SN50 peptide, a NFkappaB blocker. Hearts were then subjected to PC by 4 repeated episodes of 5-minute ischemia, each followed by 10 minutes reperfusion. All hearts were then made globally ischemic at normothermia for 30 minutes followed by 2 hours of normothermic reperfusion. Creatine kinase release and malonaldehyde formation were determined in the coronary effluent collected during reperfusion. At the end of each experiment, hearts were processed for infarct size determination and analyses of apoptosis, DNA fragmentation, NFkappaB, and Bcl-2. Myocardial infarction was reduced by PC. DMTU and SN50 abolished this cardioprotective effect of PC. PC resulted upregulation of Bcl-2 gene which was partially prevented by DMTU and SN50. Both ischemia/reperfusion and PC caused nuclear translocation and activation of NFkappaB, which was blocked by both DMTU and SN50. PC reduced cardiomyocyte apoptosis which was partially inhibited by DMTU and SN50. A substantial number of apoptotic cardiomyocytes were identified in the hearts subjected to 30 minutes ischemia and 2-hour reperfusion. PC significantly inhibited the extent of cardiomyocyte apoptosis and DMTU and SN50 reversed it only minimally. CONCLUSIONS: The results demonstrate that reactive oxygen species play a crucial role in signal transduction mediated by PC. This signaling process appears to involve NFkappaB. NFkappaB becomes translocated and activated by both ischemia/reperfusion, which induces apoptosis and PC which reduces apoptosis. However, the amount of NFkappaB binding activity is significantly higher in the PC hearts compared with ischemic reperfused hearts. The upregulation of the antioxidant gene, Bcl-2, is inversely correlated with the reduction of cardiomyocyte apoptosis associated with PC.

Oxygen free radical signaling in ischemic preconditioning.

This review will focus on the free radical signaling mechanism of preconditioning. The results from our laboratory as well as studies from other laboratories suggest that reactive oxygen species function as second messenger during myocardial adaptation to ischemia. This review provides evidence for the first time that tyrosine kinase and MAP kinases are the targets for reactive oxygen species generated in the preconditioned myocardium. The finding that p38 MAP kinase might be upstream of NF kappa B further supports our previous reports that MAPKAP kinase 2 could be the most likely link between the preconditioning and adaptation mediated by gene expression. p38 activation appears to be an important step in the translocation and activation of the nuclear transcription factor NF kappa B, which in turn may be involved in the induction of the expression of a variety of stress-inducible genes.

Interaction of bradykinin with angiotensin, prostacyclin, and nitric oxide in myocardial preservation.

This review focuses on the importance of bradykinin in myocardial preservation during ischemic arrest. Bradykinin is released from the heart spontaneously in response to ischemic stress, which may be viewed as a survival signal of the heart against ischemia. Bradykinin appears to function as a signaling molecule by controlling the release of other intracellular modulators, such as prostacyclins and nitric oxide, which also exert beneficial effects on the ischemic myocardium.

Fenestrated felt facilitates anastomotic stability and safety in "off-pump" coronary bypass.

Metal stabilizing devices used in beating heart surgery, although largely effective, occasionally slip or cause lacerations of epicardial veins or myocardium, resulting in blood loss that requires time-consuming corrective maneuvers. The use of a fenestrated felt as a cushion in conjunction with the stabilizers eliminates slipping and/or trauma, thus facilitating coronary anastomoses on the beating heart.

Influence of cardiopulmonary bypass perfusion temperature on neurologic and hematologic function after coronary artery bypass grafting.

BACKGROUND AND METHODS: A National Institutes of Health-sponsored trial (1994 to 1998) randomized patients undergoing coronary artery bypass grafting that required three or more grafts to receive perfusion at either cold (20 degrees C), tepid (32 degrees C), or warm (37 degrees C) temperature. The goal of the study was to evaluate morbidity, primarily neurologic dysfunction and secondarily hematologic factors. One thousand seven hundred seventy-seven patients were screened and 291 enrolled. Neurologic function was studied by a dedicated pool of blinded neurologists. A standard test battery termed the Mathew Scale using three subscales--cognitive function, elemental skills, and disability--was used to study central nervous system function. Hematologic function was assessed in 53 of the 291 patients with measurements of postoperative fibrinolytic potential. RESULTS: All preoperative and operative data were comparable between groups. A decrease in Mathew Scale was seen in 69% of patient from before operation to immediately after operation. However, between the early postoperative study and the 1-month follow-up, 48% of patients had returned to baseline. There was no difference noted across temperature groups in any neurologic parameter of function. In all, 55% of the group were at or above their preoperative level at 1 month. Forty-nine patients suspect for cerebrovascular accident had a computed tomographic scan, but only 13 (4.5%) had a documented cerebrovascular accident (4 patients in the warm, 3 in the tepid, and 6 patients in the cold group). Fibrinolytic changes correlated with perfusion temperature documented that fibrinolysis was most active at 37 degrees C. Thus, increasing perfusate temperature increases fibrinolysis, which was associated with reoperation for bleeding in 4% warm group patients, 1% tepid, and 0% cold group patients (0.1 > p > 0.05). No other perioperative complications were temperature related. There were 4 deaths (1.4%) (1 in the warm group, 2 in the tepid group, and 1 in the cold group). CONCLUSIONS: (1) Persistent postoperative neurologic dysfunction at 1 month occurs in 36% of patients undergoing coronary artery bypass grafting and is not related to a cerebrovascular accident; 2) perfusion temperature has no relationship to neurologic function after bypass; and 3) fibrinolytic activity is greatest at warm temperatures.

The 'primeless pump': a novel technique for intraoperative blood conservation.

PURPOSE: Hemodilution during cardiopulmonary bypass may lead to anemia requiring intraoperative transfusions. Prime removal from the cardiopulmonary bypass circuit was used to limit dilution and intraoperative transfusions. METHODS: The technique of prime removal consists of arterial and then venous side evacuation of crystalloid prior to cardiopulmonary bypass. The effectiveness of this technique, to maintain a higher hematocrit and reduce intraoperative transfusions, was studied prospectively in two consecutive groups of patients undergoing coronary revascularization (controls versus primeless). RESULTS: Intraoperative hematocrits were significantly higher (P < 0.0001) and transfusions lower (4%) in the primeless versus the control group (19%) (P = 0.003). Prime removal is of particular benefit in anemic (hematocrit < or = 35%) and/or small patients (body surface area < or = 2 m2). CONCLUSION: The technique of prime removal is simple, safe and cost-effective, reducing intraoperative transfusions, especially in small and/or anemic patients. It could be part of blood conservation strategies in most adult cardiac operations.