Myocardial Protection in Minimally Invasive Mitral Valve Surgery: Retrograde Cardioplegia Alone Using Endovascular Coronary Sinus Catheter Compared With Combined Antegrade and Retrograde Cardioplegia.

OBJECTIVE: To compare myocardial protection with retrograde cardioplegia alone with antegrade and retrograde cardioplegia in minimally invasive mitral valve surgery (MIMS). DESIGN: Retrospective study. SETTING: Tertiary care university hospital. PARTICIPANTS: The authors studied 97 MIMS patients using retrograde cardioplegia alone and 118 MIMS patients using antegrade and retrograde cardioplegia. INTERVENTIONS: The data from patients admitted for MIMS using retrograde cardioplegia (MIMS retro) between 2009 to 2012 were compared with the data from patients undergoing MIMS with antegrade and retrograde cardioplegia (MIMS ante-retro) between 2006 and 2010 (control group). Cardioplegia in the MIMS retro group was delivered solely through an endovascular coronary sinus (CS) catheter positioned under echographic and fluoroscopic guidance. Antegrade and retrograde cardioplegia was used in the MIMS ante-retro group. Data regarding myocardial infarction (MI; creatine kinase Mb, troponin T, electrocardiogram), myocardial function, and hemodynamic stability were collected for comparison. MEASUREMENTS AND MAIN RESULTS: Adequate cardioplegia administration (CS pressure >30 mmHg and asystole) was attained in 74.2% of the patients with retrograde cardioplegia alone. In 23.7% of the patients, the addition of an antegrade cardioplegia was necessary. No difference was observed in the incidence of MI (0 MIMS retro v 1 for MIMS ante-retro, p = 0.3623), difficult separation from cardiopulmonary bypass, and postoperative malignant arrhythmia. No difference was found for maximal creatine kinase Mb (39.1 [28.0-49.1] v 37.9 [28.6-50.9]; p = 0.8299) and for maximal troponin T levels (0.39 [0.27-0.70] v 0.47 [0.32-0.79]; p = 0.1231) for MIMS retro and MIMS ante-retro, respectively. However, lactate levels in the MIMS retro group were significantly lower than in the MIMS ante-retro group (2.1 [1.4-3.05] v 2.4 [1.8-3.3], respectively; p = 0.0453). No difference was observed in duration of intensive care unit stay and death. MIMS retro patients had a shorter hospital stay (7.0 [6.0-8.0] v 8.0 [7.0-9.0] days; p = 0.0003). CONCLUSION: Retrograde cardioplegia administration alone provided comparable myocardial protection to antegrade and retrograde cardioplegia during MIMS, but was not sufficient to achieve asystole in one-fifth of patients.

Reliability of Percutaneous Pulmonary Vent and Coronary Sinus Cardioplegia in the Setting of Minimally Invasive Aortic Valve Replacement: A Single-Center Experience.

OBJECTIVES: Evaluating the efficacy of 2 new percutaneous devices specifically designed to be placed through the right internal jugular vein, therefore named "necklines," for achieving retrograde cardioplegia and pulmonary venting in the setting of minimally invasive aortic valve replacement (MIAVR). DESIGN: Case series. SETTING: University-affiliated private hospital. PARTICIPANTS: Patients undergoing MIAVR. INTERVENTIONS: Necklines were placed by the anesthesiologist using transesophageal electrocardiography, with pressure guidance before the surgical procedure was initiated. MEASUREMENTS AND MAIN RESULTS: The records of 51 consecutive patients who underwent MIAVR with necklines placement were reviewed retrospectively. The access for MIAVR was through either a J-hemisternotomy or a right anterior thoracotomy. The efficacy of the 2 catheters, successful placement rate, time needed to deploy catheters, and perioperative complications were recorded. Necklines were placed successfully in all patients in 23±13 minutes. A total of 110 doses of retrograde cardioplegia were delivered at a mean flow rate of 173±35 mL/min and a mean pressure of 41±6 mmHg. The pulmonary catheter ensured venting of the heart that was graded by surgeons as "excellent" in 33 patients, "sufficient" in 12 patients, and "not adequate" in 2 patients. There were no major adverse events or deaths. CONCLUSIONS: Necklines ensure effective retrograde cardioplegia and venting of the heart, provide optimal surgical vision and access during MIAVR, and allow surgeons to operate in an unobstructed surgical field. Nevertheless, additional studies are required to determine whether the use of necklines is associated with better outcomes than those with conventional methods.

Perioperative glycemic control with a computerized algorithm versus conventional glycemic control in cardiac surgical patients undergoing cardiopulmonary bypass with blood cardioplegia.

OBJECTIVE: In critical illness, hypoglycemia and hyperglycemia seem to influence outcome. While hypoglycemia can lead to organ dysfunction, hyperglycemia can lead to surgical site infections (SSI). In cardiac surgery, the use of blood cardioplegia is associated with high blood glucose levels. A computer-based algorithm (CBA) for guiding insulin towards normoglycemia might be beneficial. The authors' primary study end-point was the duration in a predefined blood glucose target range of 80 mg/dL to 150 mg/dL. Patients with conventional therapy served as controls. DESIGN: Prospective, randomized trial. SETTING: University hospital. PARTICIPANTS: Seventy-five patients. INTERVENTIONS: The start of therapy was the beginning of cardiopulmonary bypass. Group A: Therapy with CBA and measurement of blood glucose every 30 minutes. Group B: Measurement of blood glucose every 15 minutes using the identical CBA. Group C: Conventional therapy using a fixed insulin dosing scheme. End of therapy was defined as discharge from ICU. MEASUREMENT AND MAIN RESULTS: Glucose administration during cardioplegia did not differ between groups (A: 33 ± 12 g; B: 32 ± 12 g; C: 38 ± 20 g). Glucose levels in groups A and B stayed significantly longer in the target interval compared with group C (A: 75 ± 20%; B: 72 ± 19%; C: 50 ± 34%, p < 0.01 n = 25, respectively). There were no significant differences regarding ICU stay and SSI rates. CONCLUSIONS: Early computer-based insulin therapy allows practitioners to better achieve normoglycemia in patients undergoing major cardiac surgery with the use of blood cardioplegia.

Perfusion preservation of the donor heart: basic science to pre-clinical.

As a consequence of technology improvements and refinement, perfusion of the donor heart has moved from the research laboratory to clinical studies. Multiple investigators are currently leading pre-clinical trials of devices using perfusion preservation, and one device is now in European clinical trials. One major problem with the donor heart is the high metabolism relative to other organs, and depletion of ATP leads rapidly to acidosis and necrosis of the myocardium. Two techniques in development to address the issue are normothermic and hypothermic perfusion. This review examines the current issues regarding donor heart preservation and techniques of preclinical evaluation necessary for regulatory approval.

Targeting for cardioplegia: arresting agents and their safety.

Elective temporary cardiac arrest (cardioplegia) is often required during cardiac surgery. In the 1970 s, the development of hyperkalaemic cardioplegic solutions revolutionised cardiac surgery by offering effective chemically-induced cardiac arrest and myocardial protection during global ischaemia. Despite remaining the most widely-used cardioplegic technique, hyperkalaemia can have detrimental effects due to the Na and Ca loading of the cardiac cell induced by depolarisation of the cell membrane. Efforts over the last two decades to establish better cardioplegic agents have mainly remained limited to animal experiments. The failure of these approaches to progress to clinical trials may be due to a lack of clear criteria that a cardioplegic agent should meet at a cellular level and, more importantly, at a system level. In this review we attempt to define the criteria for the optimal cardioplegic agent. We also assess the suitability and clinical potential of previously-studied cardioplegic agents and suggest cellular targets, particularly those involved in cardiac excitation-contraction coupling, that may prove to be attractive options for the development of new cardioplegic drugs. Finally, we propose a multicellular target approach using a combination of pharmacological agents in order to offer better cardioplegic solutions.

[Effect of perfusion volume of the Custodiol solution on the efficiency of cardioplegia in experiment].

The purpose of the present study was to compare the efficiency of small and standard volumes (1.5-20 and 7-10 ml/g of the myocardium, respectively) of Custodiol solution in myocardial ischemia lasting 2 and 4 hours. Experiments were carried out on 24 mongrel dogs weighing 22-36 kg under extracorporeal circulation (EC) with bicaval cannulation under moderate general hypothermia and balanced general intravenous anesthesia. According to the solution volume and cardioplegia (CP) duration, all the animals were divided into 4 groups: 1) 2-hour CP (standard volume); 2) 2-hour CP (small volume); 3) 4-hour CP (standard volume); 4) 4-hour CP (small volume); of them Groups 1 and 3 served as a control. Antegrade CP was accomplished by the conventional procedure. In Groups 1 and 3, the volume of Custodiol solution was 1000-2000 ml; in Groups 2 and 4, that was 300-600 ml depending on myocardial mass. In Groups 1 and 3, the mean duration of myocardial perfusion was 9.8+/-2.8 and 8.4+/-1.4 min, respectively; and in Groups 2 and 4, that was 4.2+/-0.7 and 4.5+/-1.4 min. Groups 3 and 4 animals received additional myocardial perfusion with Custodiol solution in a volume of 400-500 and 200-250 ml, respectively. The efficiency of myocardial protection was evaluated from the course of a reperfusion period (RP) and from central hemodynamic changes, the concentrations of glucose, lactate, malonic dialdehyde, medium-weight molecules, and blood gas and electrolyte composition of the coronary sinus. The studies were performed in stages: outcome, launch of blood flow (5-10 in); RP (30 min); complete loading (30 min); disconnection from an extracorporeal circulation apparatus. The experiment has indicated that the use of Custodiol solution in the standard volumes ensures an effective cardioplegic protection within 4 hours. Reductions in the volume and time of perfusion to the values characteristic of extracellular-type solutions cause a lower efficiency of this protection. Moreover, myocardial damage progresses as the duration of CP increases. The used Custodiol solution dose of 1.5-2.0 ml/g of the myocardium is apparent to be insufficient to set an ionic balance between cardioplegic solution and intracellular fluid, which reduces the duration of CP effect and the efficiency of myocardial protection. It may be assumed that lower perfusion volume lowers the efficiency of the buffer system of the solution and the metabolic effects of substrates. The authors consider that the decreased volume and time of perfusion of intracellular Custodial solution are unjustified and may result in the development of complications associated with inadequate cardioplegic myocardial protection.

[Myocardial protection to the hypertrophied heart: the eternal challenge]. / Proteção miocárdica ao coração hipertrofiado: o eterno desafio.

The myocardial protection allowed great advance in cardiac surgery, decreasing the mortality and making more feasible complex surgeries. Lately, the patient population elected for cardiac procedures has been changing towards elderly patients with ventricular function depressed and myocardial hypertrophy. The myocardial hypertrophy condition represents a great challenge since the beginning of the cardiac surgery. Several techniques have been described to protect the myocardial hypertrophy, however with no satisfactory results. In this manuscript we present the state of the art technique of myocardial protection.

Proteção miocárdica ao coração hipertrofiado: o eterno desafio: [revisão] / Myocardial protection to the hypertrophied heart: the eternal challenge: [review]

A proteção miocárdica permitiu enorme avanço na moderna cirurgia cardíaca, reduzindo a mortalidade e permitindo que operações cada vez mais complexas pudessem ser realizadas. A alteração na população eleita para procedimentos cirúrgicos cardiológicos mudou significativamente nas últimas décadas, com o aumento de pacientes mais idosos, com função ventricular deprimida e miocárdio hipertrofiado. Essa última condição, desde os primórdios da cirurgia cardíaca, constituiu-se em grande desafio. Diversas técnicas de proteção ao miocárdio hipertrofiado foram descritas, porém com resultados não alentadores. As características da hipertrofia miocárdica no adulto com cardiopatia cirúrgica apresentam particularidades desafiadoras. Nesse artigo, procuramos atualizar o estado da arte sobre a proteção miocárdica ao coração hipertrofiado.

The myocardial protection allowed great advance in cardiac surgery, decreasing the mortality and making more feasible complex surgeries. Latterly, the patient population elected for cardiac procedures has been changing towards elderly patients with ventricular function depressed and myocardial hypertrophy. The myocardial hypertrophy condition represents a great challenge since the beginning of the cardiac surgery. Several techniques have been described to protect the myocardial hypertrophy, however with no satisfactory results. In this manuscript we present the state of the art technique of myocardial protection.

Effects of myocardial protection in hypertrophic rabbit hearts: structural and ultra structural analysis.

OBJECTIVE: To experimentally compare the structural and ultrastructural changes in isolated hypertrophied rabbits' hearts submitted to cardiac arrest protected using sanguineous and crystalloid cardioplegia solutions. METHOD: The study comprised two experimental groups and one control group. In Experimental Group I, cardiac arrest was achieved by the continuous infusion of tepid sanguineous cardioplegia solution. In Experimental Group II, cardiac arrest was obtained by an intermittent infusion of a cold crystalloid cardioplegia solution. In the Control Group the hearts were submitted to normothermic anoxic arrest for 45 minutes. After the procedures, eight samples of the left ventricle lateral wall were collected and fixed in 10% formaldehyde and 2.5% glutaraldehyde for structural and ultrastructural analysis. RESULTS: The structural and ultrastructural results demonstrated that the hearts submitted to cardiac arrest protected by continuous tepid sanguineous cardioplegia, Group I, were better preserved and with less accentuated cellular alterations compared to those submitted to cardiac arrest protected using intermittent cold crystalloid cardioplegia and the Control Group. CONCLUSION: Continuous tepid sanguineous cardioplegia was more efficient in the preservation of the structural and ultrastructural integrity of the myocardium when compared to intermittent cold crystalloid cardioplegia.

Optimizing cardioplegia strategy for donor hearts.

Variability in organ preservation strategy has thus far prevented meaningful analysis of clinical donor heart cardioplegia strategies. This paper describes our donor heart procurement protocol, techniques, and recovery team responsibilities. We present 21 patients receiving cardiac transplantation at our institution with an adopted cardioplegia protocol. The procurement team perfusionist ensures consistent attention to myocardial protection with standards that are similar to those applied to native hearts for all congenital heart surgeries.

'When more is less'. Reviewing the safety and cost of cardioplegia delivery.

There have been several new cardioplegia delivery systems that have been developed by various manufacturers in the last few years. In this evaluation, the safety and costs associated with the present 4:1 roller pump cardioplegia delivery were compared to the Medtronic Cardioplegia Safety System (CSS). One hundred and five patients participated in a randomized, prospective evaluation. The current cardioplegia delivery system consists of using the 4:1-B MYOtherm XP disposable by Avecor Cardiovascular and a Sarns MDX 7000 roller pump. The Medtronic Cardiotherm disposable cardioplegia unit was used in conjunction with the CSS. The current delivery system will be referred to as group A and the system under evaluation will be referred to as group B. Two varying techniques are employed for cardioplegia delivery and are based on surgeon preference. An equal distribution of techniques was seen in both groups. Results indicated that in group A, a hemoconcentrator was required 60.3% of the time, whereas in group B, a hemoconcentrator was added only 25.0% of the time. The average total cardioplegia delivered in group A was 6,588 cm3 compared to 7,123 cm3 in group B. Although this is insignificant, the greatest difference was seen in the amount of crystalloid given. In group A, the crystalloid portion was 1,317 cm3 compared to only 877 cm3 in group B. There was equal weight gain and hemodilution postop in both groups. Twenty-five incidences of pressurization of the cardioplegia system occurred during the evaluation, with equal distribution in both groups. This evaluation showed that the CSS responded without fail to all pressurization incidences. The Medtronic CSS has incorporated several safety systems for pressurization and air embolism protection, which are programmable and preset by the perfusionist. The Avecor disposable has a pressurization valve that activates at a pressure greater than 600 mmHg in the cardioplegia circuit. The Sarns MDX 7,000 does not incorporate any safety shutoffs. Cost savings were achieved in two areas: hemoconcentrator use and volume of cardioplegia solution required. There was a reduction of 35% in the use of a hemoconcentrator in group B, with more total cardioplegia delivered. The cardioplegia patient cost savings in group B totaled $265.95 per case in the plain cardioplegia group and $315.95 with the amino acid cardioplegia group. The new technology incorporated into the Medtronic CSS demonstrated that it could provide more safety with less cost than the current cardioplegia pump system.

Recent experience of integrated myocardial management: the newest strategy for myocardial protection.

From April 1994 until June 1996, we exclusively utilized the integrated myocardial management (IMM) proposed by Buckberg et al. at UCLA. Two hundred sixty-two consecutive patients undergoing open heart surgery at our hospital were divided into 2 groups, the non-IMM (n = 49, from July 1993 until March 1994) and the IMM (n = 213, from April 1994 until June 1996) groups. Although many older and more severely ill patients were treated with IMM, acceptable clinical outcomes with comparable safety and efficiency were obtained. Shorter durations of total cardiopulmonary bypass (CPB) and aortic cross-clamping (AXC) were needed in the IMM group despite there being many more procedures undertaken during a single cross-clamp period.

Determination and comparison of heat exchange efficiency of four commercially available blood cardioplegia sets.

An in vitro comparison of the heat exchange properties of the Electromedics D1081A, Sarns MP-4 'Conducer Coil' 165720, Bentley HE-100 and the Shiley BCD Plus 4: 1 blood cardioplegia sets was performed. The efficiency was calculated for each heat exchanger and post-heat exchange blood path temperatures were compared. The calculated efficiency for each heat exchanger is as follows: Electromedics D1081A at 18 l/minute coil water flow (0.95); Sarns MP-4 165720 at 9 l/minute coil water flow (0.93); Bentley HE-100 at 10 l/minute coil water flow (0.91); Shiley BCD Plus at 15 l/minute coil water flow (0.90). Blood path, precoil temperatures for each unit were compared statistically with no differences found (p > 0.05). Blood side, postcoil temperatures were then compared. The average postcoil blood path temperature of the Electromedics D1081A was 1.6 degrees +/- 0.1 degree C, of the Sarns MP-4 165720 it was 2.1 degrees +/- 0.1 degree C, of the Bentley HE-100 it was 2.7 degrees +/- 0.3 degree C, and the Shiley BCD Plus 3.0 degrees +/- 0.4 degree C. The results of this experiment indicate that the average postcoil temperature of the Electromedics D1081A was lower than the Sarns MP-4 165720 (p < 0.05) which was lower than that of the Bentley HE-100 (p < 0.05) and Shiley BCD Plus (p < 0.05). No statistical difference was found between the average postcoil temperature of the Bentley HE-100 and the Shiley BDC Plus.

Warm versus cold blood cardioplegia--is there a difference?

This experimental study sought to compare the effectiveness of warm blood cardioplegia versus cold blood cardioplegia in protecting areas of ischemic myocardium during urgent coronary revascularization. In 40 adult pigs, the second and third diagonal vessels were occluded with snares for 90 minutes. All animals were then placed on cardiopulmonary bypass and underwent 45 minutes of cardioplegic arrest followed by 3 hours of reperfusion during which time the coronary snares were released. During the period of cardioplegic arrest, 10 pigs received antegrade continuous warm blood cardioplegic solution (37 degrees C) at 100 ml/min; 10 animals received retrograde warm blood cardioplegic solution at 100 ml/min; 10 received intermittent, antegrade cold blood cardioplegic solution (4 degrees C), and 10 animals received intermittent, antegrade/retrograde cold blood cardioplegic solution. Hearts protected with antegrade warm blood cardioplegic solution had the lowest pH values in the area at risk (6.59 +/- 0.10 antegrade warm blood cardioplegia versus 6.80 +/- 0.10 retrograde warm blood cardioplegia versus 6.72 +/- 0.18 antegrade cold blood cardioplegia versus 6.85 +/- 0.15 antegrade/retrograde cold blood cardioplegia and the highest area of necrosis (42% +/- 3% antegrade warm blood cardioplegia versus 26% +/- 2% [p < 0.05 from antegrade warm blood cardioplegia] retrograde warm blood cardioplegia versus 31% +/- 2% [p < 0.05 from antegrade warm blood cardioplegia] antegrade cold blood cardioplegia versus 21% +/- 2% [p < 0.05 from antegrade warm blood cardioplegia] antegrade/retrograde cold blood cardioplegia). We conclude that in the presence of an acute coronary occlusion with ischemic myocardium, warm blood cardioplegic solution should be given in a continuous retrograde fashion and does not result in myocardial protection superior to the protection that can be achieved with antegrade/retrograde cold blood cardioplegic solution.

Recovery of postischemic contractile function is depressed by antegrade warm continuous blood cardioplegia.

To assess the effectiveness of warm antegrade continuous blood cardioplegia in the setting of an acute coronary arterial occlusion, we instrumented 19 Yorkshire swine to quantitate left ventricular global, systolic, diastolic, and regional mechanics. Data were acquired before and after 10 minutes of mid-left anterior descending coronary artery occlusion followed by 60 minutes of aortic crossclamping. Cardiac arrest was induced by the antegrade infusion of 20 ml/kg of warm (37 degrees C) or cold (4 degrees C) oxygenated blood cardioplegic solution followed by either continuous warm (75 ml/min, n = 9) or intermittent cold (10 ml/kg every 20 minutes, n = 10) cardioplegic reinfusions. Left anterior descending coronary artery occlusion was released 20 minutes after aortic crossclamping and resulted in warm-arrested hearts developing a 139% increase in global oxygen consumption compared with values obtained with the left anterior descending coronary artery occluded (p < 0.02). Recovery of global left ventricle contractility, quantitated by the linear preload recruitable stroke-work relationship, was significantly worse after warm cardioplegia (52.4% +/- 5.1% versus 68.0% +/- 5.9%, warm versus cold, p < 0.05). Similarly, left anterior descending coronary artery regional ischemic zone contractility recovered 34.5% +/- 7.3% of control function with cold cardioplegia, whereas warm cardioplegia resulted in -11.36% +/- 7.46% functional recovery indicative of dyssynchronous contraction (p < 0.05). Diastolic compliance, calculated with an exponential end-diastolic pressure-versus-volume relationship, was not changed postischemically in either group. These data suggest that warm antegrade blood cardioplegia may potentiate acute ischemic injury and provide inadequate myocardial protection.

Fluosol cardioplegia results in complete functional recovery: a comparison with blood cardioplegia.

Blood cardioplegia is considered by many to be the preferred solution for myocardial protection. Proposed benefits include the ability to deliver oxygen and the ability to maintain metabolic substrate stores. However, the decreased capacity of blood to release oxygen at hypothermic conditions as well as the presence of deleterious leukocytes, platelets, and complement may limit complete functional recovery. Fluosol is an asanguineous solution with the ability to bind and release oxygen linearly at low temperatures. Neonatal piglet hearts (24 to 48 hours old) were excised and supported on an isolated, blood-perfused working heart model. After baseline stroke-work index was determined, hearts were arrested with either normocalcemic blood cardioplegia (group 1, n = 8) or normocalcemic Fluosol cardioplegia (group 2, n = 8). Cold cardioplegia was administered at 45 mm Hg every 20 minutes for 2 hours. Hearts were then reperfused with whole blood. Functional recovery, expressed as percent of control stroke-work index, was determined 60 minutes after reperfusion at left atrial pressures of 3, 6, 9, and 12 mm Hg. Functional recovery at 60 minutes was similar between group 1 (95%, 93%, 93%, 88%) and group 2 (100%, 94%, 94%, 95%) at left atrial pressures of 3, 6, 9, and 12 mm Hg, respectively. Mean lactate consumption 5 minutes after reperfusion was significantly greater (p = 0.0001) in group 1 (31.8 +/- 6.3 micrograms.min-1 x g-1) than in group 2 (-0.59 +/- 0.1 microgram.min-1 x g-1), indicating superior metabolic recovery in the blood cardioplegia hearts. Edema formation, as determined both by water content (group 1, 81.10%; group 2, 81.63%) and by electron microscopy, was not significantly different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Retrograde coronary sinus cardioplegia in the presence of persistent left superior vena cava.

Administration of retrograde cardioplegia is hampered by the presence of a persistent left superior vena cava, which results in excessive runoff of solution into the persistent left superior vena cava and the right atrium. Technical modifications are described that permitted aortic valve replacement to be performed in a patient with persistent left superior vena cava using only retrograde cardioplegia.

Annulo-aortic ectasia extending to the arch: composite graft repair with circulatory arrest.

OBJECTIVE: To examine the results of surgery performed in patients with annulo-aortic ectasia extending to the arch. DESIGN: Retrospective hospital record review. SETTING: A Canadian teaching hospital. PATIENTS: Five patients (mean age 57 years) had annulo-aortic ectasia with severe aortic insufficiency, a maximum aneurysmal diameter ranging from 6.5 to 13 cm at the root or ascending aortic level, and extending into the arch with a diameter of at least 5 cm at the innominate artery level. They all had reconstruction with a composite prosthetic valve and Dacron tube graft employing standard techniques of aortic root replacement as well as aortic arch reconstruction with a single bevelled anastomosis in a state of profound hypothermia and circulatory arrest. MAIN RESULTS: No perioperative deaths, neurological complications nor significant cardiac complications. At a median follow-up period of 46 months all patients are alive, free from cardiovascular symptoms and show no evidence of aortic aneurysmal disease. CONCLUSIONS: This safe, effective and durable repair should be applied to selected patients with annulo-aortic ectasia which extends to the arch.

Cerebral consequences of hypothermic circulatory arrest in adults.

Despite widespread use of hypothermic circulatory arrest (HCA) in aneurysm surgery and for repair of congenital heart defects, there is continued concern about possible adverse cerebral sequelae. The search for ways to improve implementation of HCA has inspired retrospective clinical studies to try to identify risk factors for cerebral injury, and clinical and laboratory investigations to explore the physiology of HCA. At present, risk factors associated with less favorable cerebral outcome after HCA include: prolonged duration of HCA (usually greater than 60 min); advanced patient age; rapid cooling (less than 20 min); hyperglycemia either before HCA or during reperfusion; preoperative cyanosis or lack of adequate hemodilution; evidence of increased oxygen extraction before HCA or during reperfusion; and delayed reappearance of electroencephalogram (EEG) or marked EEG abnormality. Strategies advocated to increase safety of HCA include: pretreatment with barbiturates and steroids; use of alpha-stat pH regulation during cooling and rewarming; intraoperative monitoring of EEG; slow and adequate cooling, including packing of the head in ice; monitoring of jugular venous oxygen content; hemodilution; and avoidance of hyperglycemia. Current investigation focuses on delineating the relationship of cerebral blood flow (CBF) to cerebral oxygen consumption and glucose metabolism during cooling, HCA, rewarming, and later recovery, and identifying changes in acute intraoperative parameters, including the presence of intracerebral enzymes in cerebral spinal fluid, with cerebral outcome as assessed by neurological evaluation, quantitative EEG, and postmortem histology. Clinically, intraoperative monitoring of EEG and measurement of CBF by tracer washout or Doppler flows are contributing to better understanding of the physiology of HCA, and in the laboratory, nuclear magnetic resonance (NMR) spectroscopy has provided valuable insights into the kinetics of intracerebral energy metabolism. Promising strategies for the future include investigation of other pharmacological agents to increase cerebral protection, and use of "cerebroplegia" or intermittent perfusion between intervals of HCA to improve cerebral tolerance for longer durations of HCA.

Tumor-related obstruction of the inferior vena cava extending into the right heart--a plea for surgery in deep hypothermic circulatory arrest.

This study reviews eight patients, 39-63 years old, with tumor-related obstruction of the inferior vena cava (IVC) extending into the right atrium (n = 5) and ventricle (n = 3). Five patients suffered from renal cell carcinoma, 3 from sarcomatous disease. The general approach was a median sternotomy and laparotomy with hypothermic circulatory arrest (17.0-20.5 degrees C; 23-46 min) in six patients, while in two patients, the IVC was clamped sequentially under moderate hypothermia and extracorporeal circulation. Four patients had tumor infiltration of the IVC necessitating partial caval resection. In three, the IVC was reconstructed by fabric patches or tubular prothesis. In one patient, the continuity of the IVC was interrupted permanently. Three patients underwent nephrectomy during the same procedure, two before and one after IVC disobliteration. In one patient each, pulmonary embolectomy and intrahepatic IVC stenting were performed. Two patients died early, one due to uncontrollable hemorrhage the other due to non-cardiogenic pulmonary edema. Six patients were discharged in good physical condition and are still alive at a mean follow-up of 24 months. Five patients have since remained free of recurrence, one patient underwent three further surgical interventions for bone metastases. We feel that IVC desobliteration is feasible in selected cases with extended tumor-related obstruction with an acceptable early risk and late outcome.