Ovarian function 6 years after cryopreservation and transplantation of whole sheep ovaries.

Whole ovary cryopreservation and transplantation has been proposed as a method for preserving long-term ovarian function. This work reports ovarian function 6years post transplantation of frozen-thawed whole sheep ovaries. Three 9-month-old Assaf sheep underwent unilateral oophorectomy to provide organs for the experiments. After perfusing with cold University of Wisconsin solution supplemented with 10% dimethyl sulphoxide, ovaries were cryopreserved using unidirectional solidification freezing technology. After thawing, ovaries were re-perfused and re-transplanted orthotopically by microvascular re-anastomosis, to the contralateral ovarian pedicle after removing the remaining ovary. Six years following transplantation and after inducing superovulation, the sheep were killed and the ovaries analysed. Two ovaries had normal size and shape showing some recent corpora lutea, while the third showed atrophic changes. A total of 36 antral follicles were counted by transillumination and four germinal vesicle oocytes were aspirated and matured in vitro to metaphase II. Serum progesterone concentrations were indicative of ovulatory activity in one of the three sheep. Histological evaluations revealed normal tissue architecture, intact blood vessels and follicles at various stages. Currently, this is the longest recorded ovarian function after cryopreservation and re-transplantation. Cryopreservation of whole ovaries, using directional freezing combined with microvascular anastomosis, is a promising method for preserving long-term reproductive capacity and endocrine function.

Off-pump coronary artery bypass grafting in a patient with Child class C liver cirrhosis awaiting liver transplantation.

We report the case of a Child class C cirrhotic patient who was diagnosed with coronary artery disease in the course of his pretransplantation evaluation. He underwent off-pump coronary artery bypass grafting (OPCAB), which was complicated with acute renal failure. The morbidity and mortality associated with cardiac operation in patients with cirrhosis is discussed, and the potential advantage of OPCAB in this patient population is emphasized.

Oocyte recovery, embryo development and ovarian function after cryopreservation and transplantation of whole sheep ovary.

BACKGROUND: Successful cryopreservation of a whole ovary may provide a solution for women with premature ovarian failure. The aim of this study was to evaluate the function of cryopreserved whole sheep ovaries both in vitro and in vivo. METHODS: Transplantation of frozen-thawed intact ovaries was performed on eight sheep by artery and vein anastomosis to the contralateral ovarian artery and vein. The remaining ovary was removed. Oocyte aspiration was performed 1 and 4 months post-transplantation. Serum progesterone levels were measured after 24 and 36 months. Magnetic resonance imaging (MRI) was carried out 12 months after transplantation. RESULTS: Progesterone activity was detected in three sheep from 24 to 36 months post-transplantation. Oocyte retrieval was successful in two sheep and parthenogenic activation has resulted in embryonic development up to the 8-cell stage. MRI revealed an intact ovary with small follicles and intact blood vessels. CONCLUSIONS: Whole ovaries, and the follicles and blood vessels they contain, are able to survive cryopreservation. In addition, MRI has shown that blood vessels were intact and that normal blood flow had resumed to the transplant. We conclude that immediate and long-term hormonal restoration and normal ovulation is possible after cryopreservation and transplantation of whole ovaries in sheep.

Ischaemic preconditioning but not isoflurane prevents post-ischaemic production of hydroxyl radicals in a canine model of ischaemia-reperfusion.

BACKGROUND AND OBJECTIVE: Isoflurane has been shown to mimic ischaemic preconditioning (IPC). The protective effect of IPC, or applying isoflurane or perfusion with the 'push-pull' complex zinc-desferrioxamine (Zn-DFO) in the canine heart, was investigated. METHODS: Thirty minutes after salicylate administration (100 mg kg(-1)) the heart was exposed. All dogs were subjected to a 10 min left anterior descending artery occlusion followed by 2 h of reperfusion. In Group I (n = 9) isoflurane (2.5%) was administered 10 min prior to and during ischaemia. In Group II (n = 8), IPC was elicited by 5 min coronary artery occlusion, followed by 5 min of reperfusion, prior to the 10 min ischaemia. In Group III (n = 9) Zn-DFO (2.5 mg kg(-1)) was given 10 min prior to ischaemia. The effects of these interventions were compared to control (n = 10). Coronary sinus blood concentrations of salicylate, 2,3-dihydroxybenzoic acid (DHBA), lactate, pH and oxygen content were monitored. RESULTS: In the control group, 2,3-DHBA increased by 32% above the pre-ischaemic value (P < 0.05). In contrast, in the IPC hearts, a significant decrease in the production of 2,3-DHBA was observed (40% lower than baseline, P < 0.01). In the isoflurane group only a 13% (and non-significant) decrease was noticed. In the Zn-DFO group a 33% decrease was found (P < 0.01). The increase in lactate concentrations in the IPC and Zn-DFO groups was significantly smaller than that of control and isoflurane groups. CONCLUSIONS: IPC protected the heart against the deleterious effects of reperfusion, possibly by amelioration of the level of oxygen-derived reactive species, and the complete inhibition of reactive hydroxyl radical production. Isoflurane did not prove to be as effective in reducing the free radical damage.

Lung cancer resection or aortic graft replacement with simultaneous myocardial revascularization without cardiopulmonary bypass.

BACKGROUND: The concomitant occurrence of lung cancer or other thoracic problems requiring surgical treatment in patients with significant coronary artery disease is uncommon. METHODS: Three patients underwent revascularization of the anterior descending artery, without cardiopulmonary bypass, with simultaneous pulmonary lobectomy (two patients) or replacement of an obstructed descending aortic graft (one patient). RESULTS: Postoperative ventilation time was < 3 h, and no morbidity related to the combined procedure occurred during midterm follow-up. CONCLUSIONS: This one-stage approach allowed the immediate solution of two intrathoracic comorbidities, reducing expenses and suffering to the patients and minimizing the risk of bleeding or tumor dissemination secondary to extracorporeal circulation-induced coagulopathy and immunosuppression.

[Concomitant surgery--coronary artery bypass and pulmonary lobectomy].

Coronary artery disease amenable to percutaneous interventions or coronary artery bypass grafting, and resectable lung cancer are major causes of morbidity and mortality. We present our experience in the treatment of 3 patients (men aged 64 and 66 and a woman of 77) who each had significant coronary artery disease and a resectable lung tumor. They underwent combined coronary artery bypass grafting and pulmonary lobectomy. We conclude from our experience and review of the literature that concomitant surgery in such cases is safe and effective, decreases suffering, and decreases the cost of 2 separate invasive procedures.

Mitral valve replacement in patients after aortic valve replacement.

BACKGROUND: Mitral valve replacement in patients who previously had undergone aortic valve replacement is a technical challenge. The rigid aortic prosthesis limits visualization of the anterior mitral annulus and placement of sutures. METHODS: Reoperative mitral valve replacement was performed in five patients after aortic valve replacement. Two patients underwent resternotomy to allow verification of normal aortic prosthetic valve function. Anterolateral right thoracotomy was used for reentry in the remaining three patients. Exposure of the anterior mitral annulus was accomplished by initial traction on the intact anterior leaflet, with resection of this leaflet only after placement of sutures. RESULTS: All patients survived the surgical procedure and are well 2 to 30 months after operation. In one patient it was impossible to open one cusp of the mitral prosthesis, nor was it possible to rotate the valve. The valve was reimplanted, but sutures were tied only after testing for full free cusp motion. CONCLUSIONS: When appropriate, right thoracotomy incision offers excellent exposure of the mitral valve with minimal dissection. Placement of sutures along the anterior portion of the annulus is facilitated by traction downwards on the anterior leaflet. Full range of motion of the prosthetic cusps should be verified before tying the sutures.

Coronary Artery Bypass Grafting without Cardiopulmonary Bypass: Improvement in Cardiac Function Following Enflurane Anaesthesia during Coronary Occlusion.

Severe adverse effects, especially neurologic complications after cardiopulmonary bypass have lead to the development of techniques for performing coronary artery bypass graft surgery without cardiopulmonary bypass. Laboratory and clinical studies confirmed the positive role of enflurane anaesthesia in preventing myocardial dysfunction following an ischaemic interval. The aim of this study was to evaluate the haemodynamic response to enflurane anaesthesia during single graft coronary bypass surgery without cardiopulmonary bypass. Twenty one patients were divided randomly into two groups: control and enflurane groups. Haemodynamic parameters and those derived from a pulmonary artery catheter were recorded and analysed. In the enflurane group, the amount of fentanyl administered was considerably less than in the control group: 25.7 +/- 3.8 microg/kg vs 36.8 +/- 1.6; p=0.03. The mean arterial pressure during enflurane administration was lower than in control group, but the difference was not significant. Despite a dearease in left ventricular function during the performance of the anastomosis in the enflurane group, a significant recovery was noted after 20 minutes of reperfusion: cardiac index increased from 1.4 +/- 0.1 to 1.85 +/- 0.1 L/min/m2 and left ventricular stroke work index from 15.8 +/- 1.1 to 27.7 +/- 6.7 g.m.m2 . In the control group, the deterioration in cardiac function observed during the graft anastomosis did not recover till the end of the surgical procedure. We conclude that enflurane anaesthesia may be a positive addition to fentanyl-based anaesthesia by improving myocardial function following CABG without bypass surgery.

Systolic pressure variation predicts the response to acute blood loss.

STUDY OBJECTIVE: To evaluate systolic pressure variation (SPV), defined as the difference between the maximum and minimum systolic blood pressure measured during a controlled mechanical respiratory cycle, as a predictor of the cardiac output (CO) response to an acute decrease in ventricular preload. DESIGN: Prospective study with each subject serving as his or her own control. SETTING: Cardiac surgery operating rooms of a university medical center. PATIENTS: 15 adults with good ventricular function undergoing coronary artery bypass grafting. INTERVENTION: During stable anesthetic conditions and before surgical stimulation, 500 ml of blood was removed from each patient over 10 minutes. MEASUREMENTS AND MAIN RESULTS: CO, central venous pressure (CVP), pulmonary artery diastolic pressure, and pulmonary artery occlusion pressure (PAOP), and SPV before and after phlebotomy were recorded. Phlebotomy was associated with significant decreases in CVP, PAOP, and CO, and an increase in SPV. Of these variables, SPV was the best predictor of the percent decrease in CO resulting from blood loss. CONCLUSION: SPV is a dynamic measurement, which, by revealing the response to small cyclical changes in left ventricular preload that occur during the controlled mechanical respiratory cycle, is a better predictor than central filling pressures of the response of CO to acute decreases in preload that occur as a result of acute blood loss.

Cerebral protection using retrograde cerebral perfusion during hypothermic circulatory arrest.

BACKGROUND: Retrograde cerebral perfusion through the superior vena cava (SVC) has been proposed to protect the brain from ischaemic injury during profound hypothermic circulatory arrest (PHCA). Its contribution to cerebral protection is unclear. Furthermore, the addition of anaesthetic or vasodilating agents to the SVC perfusate to enhance brain protection, has never been described. METHODS: In three patients undergoing repair of the ascending aorta utilizing PHCA, the upper body was retrogradely perfused with cold (16 degrees C) blood through the SVC by the cardiopulmonary bypass pump. Electroencephalographic activity was monitored using a computerized electroencephalographic monitor (Cerebro Trac 2500, SRD). Perfusion pressure was measured at a port in the cannula connector. Etomidate or thiopentone was injected into the SVC perfusate to arrest reappearing electroencephalographic activity. Nitroglycerin or nitroprusside was injected into the perfusate to increase retrograde flow and maintain a constant perfusion pressure. RESULTS: During PHCA periods of up to 61 min, recurrent electroencephalographic activity was abolished by the retrograde administration of small boluses of etomidate (total 50 mg) or thiopentone (total 500 mg). Nitroprusside (100 micrograms) and nitroglycerin (2 micrograms.kg-1.min-1) increased retrograde flow from 220 to 550 and 660 ml.min-1, respectively, while maintaining perfusion pressure (25-26 mmHg). Recovery from anaesthesia and surgery was uneventful, with no adverse neurological sequelae. CONCLUSION: Injection of anaesthetic agents into the retrograde SVC perfusate during PHCA, can suppress reoccurring electroencephalographic activity and retrograde injection of vasodilators can facilitate an increase in perfusion. It is suggested that both may augment brain protection.

Single pass lead VDD pacing in children and adolescents.

Implantation of permanent pacemakers in children and adolescents is possible but usually is limited to single chamber generators. The natural growth of these patients may require physiological pacing, but until recently two leads were required for this type of pacing. The single pass lead VDD pacing mode makes possible physiological pacing by using only one lead, for both atrial sensing and ventricular sensing and pacing. The feasibility of VDD pacing using endocardial lead was evaluated in 16 children and adolescents with congenital or postsurgical atrioventricular block. Their mean age was 7.9 +/- 4.9 years (range 1-16 years) and the smallest patient's weight was 8.2 kg. In all the patients, a single pass pacing lead with atrial sensing rings and bipolar ventricular pacing and sensing capability was implanted through the left or right subclavian vein. The pacemaker generator was implanted in a rectopectoral position. The mean atrial electrogram during the implantation was 4.2 +/- 2.1 mV and 2.6 +/- 1.9 mV after a mean of 1 week. The ventricular pacing threshold was 0.5 +/- 0.2 V; the ventricular pacing impedance was 560 +/- 95 omega; and the ventricular electrogram amplitude was 9.9 +/- 2.1 mV. This is a first report to demonstrate the feasibility of atrial synchronous ventricular endocardial pacing using a single pass lead in a relatively large group of children and adolescents.