Off-pump coronary artery bypass grafting is a safe and effective treatment modality for Asian patients requiring coronary revascularisation.

INTRODUCTION: Off-pump coronary artery bypass grafting (OPCABG) is gaining widespread acceptance as the preferred choice for myocardial revascularisation. However, no definite data exist as to whether it is better than conventional CABG. We aimed to study the efficacy of the procedure in our patients, which constituted of a predominantly Asian population. METHODS: Between January 2000 and December 2002, 1062 patients underwent isolated coronary artery bypass in our institution. 184 patients (17.3 percent) underwent OPCABG. Patients were preoperatively prospectively risk stratified under the EuroSCORE risk assessment model under high, medium and low risk classes thereby making them comparable. Post-operative complications, intensive care unit stay, hospital stay, types of grafts done were then analysed in these different risk classes. RESULTS: The incidence of off-pump procedures showed a gradual increase over the last three years in this institution. A reduction in the number of post-operative complications, hospital stay, intensive care unit stay and mortality in the off-pump group was observed. Certain differences were found to be statistically significant. CONCLUSION: Off-pump CABG is a safe and viable alternative to conventional CABG as a treatment modality for surgical coronary revascularisation.

Myocyte transplantation for myocardial repair: a few good cells can mend a broken heart.

Cell transplantation is a potential therapeutic approach for patients with chronic myocardial failure. Experimental transplantation of neonatal and fetal cardiac myocytes showed that the grafted cells can functionally integrate with and augment the function of the recipient heart. Clinical application of this approach will be limited by shortage of donors, chronic rejection, and because it is ethically contentious. By contrast skeletal myoblasts (satellite cells) are abundant and can be grafted successfully into the animal's own heart even after genetic manipulation in vitro. Functional integration of myoblasts, however, is hampered by the lack of intercellular gap junction communication and the difference in excitation-contraction coupling between skeletal and cardiac myocytes. In experimental studies several other cell types have been used to augment cardiac function. In this review we discuss the published results of myocyte transplantation with emphasis on potential sources of cells, the ethics of using donor embryonic and fetal cardiomyocytes, genetic transformation of skeletal myoblasts for myocardial repair, and the functional benefits of cell transplantation to the failing heart.

Thoracolaparoscopic repair of traumatic diaphragmatic rupture.

Diaphragmatic rupture may occur after blunt or penetration trauma caused by the application of a powerful external force. Diaphragmatic rupture usually is repaired via laporotomy and/or thoracotomy, depending on the associated organ injury. The case of a 49-year-old man with traumatic rupture of the left hemidiaphragm is presented. Preoperatively, diaphragmatic rupture with herniation of the stomach into the left thoracic cavity was confirmed by computed tomography scan of the thorax. Under thoracoscopic guidance, the stomach, spleen, and omentum were repositioned in the abdominal cavity, and the rupture site (10 cm) was closed by nonabsorbable suture. A subsequent laparoscopy was performed to assess the efficacy of the repair and the absence of any abdominal organ injury. The patient was discharged from hospital without any respiratory or abdominal symptoms. Our report confirms that in the case of a patient with penetration injuries to the lower chest and upper abdomen, a combined thoracoscopic and laparoscopic approach may offer both diagnostic and therapeutic benefits with reduced surgical trauma. We conclude that thoracoscopic repair of traumatic diaphragmatic rupture can be used safely when no abdominal organ injuries are found.

Efficiency of a high-titer retroviral vector for gene transfer into skeletal myoblasts.

BACKGROUND: Genetic transformation of skeletal myoblasts for myocardial repair is dependent on an efficient gene transfer system that integrates the genes of interest into the genome of the target cell and its progeny. The aim of this investigation was to evaluate the use of a new retrovirally based gene transfer system for this purpose. METHODS: MFGnlslacZ retroviral vector, packaged in high-titer, split-genome packaging cell line (FLYA4) was used to transduce the skeletal myoblast cell line L6. L6 cells, cultured in 10% fetal calf serum, were transduced with the MFGnlslacZ vector by means of filtered supernatant from FLYA4 cells. Transduced L6 cells were divided into four groups. Group I cells were fixed as myoblasts 3 days after transduction. Group II cells were allowed to differentiate into myotubes. Group III cells were split every 3 days for 4 months. Group IV cells were split as in group III but then allowed to differentiate into myotubes. All samples were fixed and stained for beta-galactosidase activity. The effects on gene transfer of transforming growth factor-beta, insulin-like growth factor-I, and platelet-derived growth factor were determined by spectrophotometric assay of beta-galactosidase activity in cells transduced in the presence or absence of serum with 0 to 200 ng/ml of each growth factor. RESULTS: Morphometric analysis showed that 66.3% +/- 3% to 69.6% +/- 6% of cells in group I to IV expressed the lacZ reporter gene. In the presence of serum, transforming growth factor-beta significantly inhibited gene transfer, whereas insulin-like growth factor-I and platelet-derived growth factor significantly enhanced gene transfer. In absence of serum, however, only platelet-derived growth factor enhanced retrovirally mediated gene transfer into skeletal myoblasts. CONCLUSION: MFG retroviral vectors packaged in FLYA4 cells are efficient in gene transfer into skeletal myoblasts and result in transgenic expression that is maintained after repeated cell division, differentiation, or both. Platelet-derived growth factor enhances retrovirally mediated gene transfer into skeletal myoblasts.

Indications and outcome of surgery for pulmonary aspergilloma.

BACKGROUND: The indications and the outcome of surgery for pulmonary aspergilloma remain highly controversial. The short term and long term results of lung resection or cavernostomy in 24 patients with pulmonary aspergilloma are reported. METHODS: The case notes of 27 consecutive patients referred for surgical assessment for pulmonary aspergilloma at the Royal Brompton Hospital over the last 14 years were reviewed. Patients were categorised into four classes according to their fitness for lung resection and the severity of their symptoms. Severe symptoms were defined as life threatening haemoptysis or other symptoms requiring more than one hospital admission. Class I (n = 1), fit individual with mild or no symptoms; class II (n = 17), fit individuals with severe symptoms; class III (n = 1), unfit individual with no symptoms; and class IV (n = 8), unfit individuals with severe symptoms. Two asymptomatic patients and one on an IVOX pump were not accepted for surgery. Lung resection was performed in all 17 patients with class II disease, comprising segmentectomy only in five patients, lobectomy and segmentectomy in seven, and a completion pneumonectomy in five patients. Cavernostomy was performed in seven patients with class IV disease. RESULTS: Surgery was often complicated by prolonged air leakage and infection of residual space. There was no operative mortality in the group treated by resection whereas two of those who underwent cavernostomy died in the early postoperative period. All survivors were followed up for a median of 17 months (range 1-72 months); 19 were alive and had no symptoms attributable to aspergilloma. Late recurrence occurred in two patients in the cavernostomy group. The only late death occurred in the resection group five months postoperatively and was attributed to end stage renal disease. CONCLUSIONS: Lung resection in selected patients with complicated aspergilloma can be performed with low operative mortality. Cavernostomy is associated with high mortality and morbidity and should therefore only be performed in patients with life threatening symptoms who are unfit for lung resection.

Mediastinitis in patients undergoing cardiopulmonary bypass: risk analysis and midterm results.

BACKGROUND: Deep sternal wound infection (mediastinitis) occurred in 21 out of 4043 consecutive patients who underwent a cardiopulmonary bypass procedure (incidence of 0.4%). METHODS: Clinical characteristics of patients who developed mediastinitis (group I) were compared to those of patients who had no mediastinal infection (group II). RESULTS: Hospital mortality was significantly higher in group I (14% vs 3.8%) (p<0.001). Mean hospital stay was longer in group I (36 days vs 7 days) (p<0.001). Multivariate analysis identified the following variables as significant risk factors for developing postoperative mediastinitis: diabetes; relative risk (RR)=3.02, 95% confidence limits (CL)=1.68-5.45, resternotomy for bleeding: RR=5.43, CL=1.85-15.92, associated leg wound infections; RR=16.55, CL=5.32-51.49, the need for 3 or more units of blood transfusion; RR=2.48, CL=1.82-3.39, obesity; RR 4.96, CL 2-12.25. Group I patients were categorised according to a recently proposed classification for mediastinitis (reference 1). Type I (n=17), mediastinitis presenting within 2 weeks following surgery in the absence of risk factors. Type II (n=2), mediastinitis presenting at 2-6 weeks following surgery in the absence of risk factors. Type IIIA (n=2), mediastinitis type I in the presence of one or more risk factor(s). Wound debridement and closed mediastinal irrigation was performed in 19 patients; 15 cases with type I, 2 with type II, and 2 with type IIIA. Primary closure without irrigation was performed in 2 type I patients. The primary intervention failed in 3 patients, two of whom died. A third patient died 4 weeks after an apparently successful treatment of type I mediastinitis. Midterm follow-up (mean of 18 months) of 18 patients showed that 16 patients were alive and well, there was one late death, and one patient had chronic wound pain. CONCLUSION: Diabetes, obesity, associated leg-wound infection, and the need for repeated blood transfusions are associated with high risk of mediastinitis. Closed mediastinal irrigation for mediastinitis type I can yield satisfactory functional and cosmetic midterm results.

Effects of cardiomyoplasty on cardiac growth in rats.

BACKGROUND AND AIM OF THE STUDY: Cardiomyoplasty (CMP) has been proposed as a treatment for pediatric patients, but restriction of cardiac growth by the muscle wrap is a potential source of concern. This possibility was investigated in an immature animal model. METHODS: Six-week-old rats (body weight 203.8 +/- 5.4 g, mean +/- SEM) underwent either left thoracotomy with CMP (group I, n = 7), or thoracotomy without CMP (group II, n = 8). A third group (group III, n = 7) served as untreated controls. Final measurements were made 20 weeks later after body weights had reached a plateau. RESULTS: Preoperative body weights were not significantly different between the groups. At elective sacrifice, the body weights of animals that underwent surgery did not differ significantly (group I, 558.0 +/- 21.5 g and group II, 617.3 +/- 20.3 g), but were significantly less than those of control animals (727.6 +/- 13.3 g, p < 0.001 and p < 0.01, respectively). Cardiac ventricular weights in the CMP group were significantly less than those of control animals (group I, 1.21 +/- 0.06 g; group III 1.45 +/- 0.04 g; p < 0.01), but were not statistically different from those of the sham thoracotomy group (group II, 1.36 +/- 0.05 g). Mean left ventricular end-diastolic volumes were similar in all groups (group I, 0.67 +/- 0.07 mL; group II, 0.66 +/- 0.07 mL; and group III, 0.69 +/- 0.10 mL; p = ns). CONCLUSIONS: A major surgical procedure impairs growth in juvenile rats. no evidence emerged from this study for additional restriction of cardiac development due to cardiac wrapping. However, studies that include stimulated muscle wraps are needed before CMP should be considered for the pediatric age group.

Extended criteria for cardiac allograft donors: a consensus study.

BACKGROUND AND METHODS: To achieve a consensus regarding extending the current criteria for referring potential cardiac allograft donor, we sent a detailed questionnaire to all heart transplant surgeons in the United Kingdom. RESULTS: Replies representing the opinion of 16 heart transplant surgeons (88% response rate) suggest that the majority believe that donor age could be extended up to 55 years even in the absence of a coronary angiogram or echocardiogram. Family history of ischemic heart disease, history of hyperlipidemia or smoking, and brain death caused by paracetamole or barbiturates overdose were not considered prohibitive to cardiac allograft donation. Similarly, chest trauma, prolonged mechanical ventilation, pre-referral cardiac arrest or hypotension for any length of time, and nonspecific ST-segment elevation were not considered to be contraindications. By contrast, significant Q waves in a recent electrocardiogram, the presence of hepatitis C antibodies, pulmonary capillary wedge pressure more than 20 mm Hg, and dependency on multiple inotropic support were considered definite exclusion criteria. Donor hormonal resuscitation (T3-cocktail), insertion of a Swan-Ganz catheter, and direct measurement of intracavitary pressure at the time of retrieval were considered unnecessary by more than 80% of respondents. There was no consensus of opinion regarding the use of donors above the age of 55 years, brain death caused by carbon monoxide poisoning, history of diabetes mellitus, alcohol or drug abuse, systemic infections, electrocardiographic evidence of left ventricular hypertrophy, or the maximum dose of inotropic support required to maintain satisfactory hemodynamics. CONCLUSIONS: The number of potential cardiac allograft donors can be increased by extending the donor age to 55 years. Brain death caused by Paracetamole and barbiturate overdose may not prohibit organ donation.

Postoperative mediastinitis: classification and management.

Although the incidence of mediastinal wound infection in patients undergoing median sternotomy for cardiopulmonary bypass is less than 1%, its associated morbidity, mortality, and "cost" remain unacceptably high. There is considerable lack of consensus regarding the ideal operative treatment of complicated median sternotomy wounds. The aim of this article is to review the current preventive, diagnostic, and therapeutic techniques offered to patients with mediastinitis. We also propose a new classification for postoperative mediastinitis. Data from the English-language literature suggest that the type of mediastinitis and direct assessment of the mediastinum under general anesthesia are the main determinants of the nature of subsequent operative treatment. Wound debridement and removal of foreign materials are essential steps of whatever procedures are applied. Closed mediastinal irrigation can be successful in type I mediastinitis, whereas major reconstructive operation is probably the treatment of choice for patients with mediastinitis types II to V. Refinement of the current diagnostic tools and further evaluation of the benefits of primary sternal fixation in combination with a reconstructive procedure in mediastinitis types I to III could improve the outcome of this dreaded complication.

Factors affecting the integrity of latissimus dorsi muscle grafts: implications for cardiac assistance from skeletal muscle.

BACKGROUND: Severe latissimus dorsi muscle damage may compromise cardiomyoplasty performance. We analyzed factors underlying the damage produced in 20 sheep latissimus dorsi muscles by isolating the influences of electrical stimulation, mobilization (with some loss of vascular supply), loss of normal resting tension, or a combination of these. METHODS: In group I (n = 3), the muscle was mobilized except for its neurovascular pedicle and reattached at normal resting length. In group II (n = 3), the muscle was mobilized and reattached at about 80% of resting length. Groups III (n = 6) and IV (n = 4) were as groups I and II except that continuous indirect stimulation at 2 Hz was added after 2 weeks. In group V (n = 4), the undisturbed muscle received stimulation alone. After 10 to 12 weeks, muscle samples were taken for morphometric analysis. RESULTS: Loss of resting muscle tension appeared to be the single most damaging intervention, though mobilization and stimulation had further deleterious effects. The worst damage was seen when all three factors were combined, when 60% of the muscle cross section was occupied by connective tissue and fat. The changes were significantly more severe in the distal than in the proximal part of the muscle, implicating ischemia as a contributory factor. CONCLUSIONS: Fiber damage reduces the effectiveness of muscle grafts used for cardiac assistance and merits further systematic investigation.

Progressive tracheal and superior vena caval compression caused by benign neurofibromatosis.

The case history presented is of a patient with progressive tracheal and superior vena caval compression caused by a benign neurofibroma, a previously unrecognised feature of neurofibromatosis. The patient was successfully treated by surgical decompression.