1638 Decade-Long Trends in Surgery for Acute Type A Aortic Dissection

Background

Little is known about unwarranted variations in care and outcomes of patients who undergo surgical repair for type A acute aortic dissection(TAAD). We aim to investigate decade-long trends in TAAD surgical repair in England.

Method

Retrospective review of the National Institute for Cardiovascular Outcomes Research (NICOR) National Adult Cardiac Surgery Audit (NACSA) registry from January 2009 to December 2018 , which prospectively collects demographic and peri-operative clinical information for all adult cardiac surgery procedures in the UK.

Results

Over the 10-year period,3,686 TAAD patients underwent surgical repair in England. A steady doubling in the overall number of operations conducted in England was observed from 237 cases recorded in 2009 to 510 in 2018. Number of procedures per hospital per year also doubled, from 10 in 2009 to 21 in 2018. The risk profile of the operated patients remained unchanged. Overall, in-hospital mortality was 17.4% with a trend toward lower mortality in the most recent years (from 22.8% in 2009 to 14.7% in 2018). There was a significant variation in operative mortality across regions with a trend towards lower mortality in regions with a high-volume hospital.

Conclusions

Surgery is the only treatment for acute TAAD but is associated with high mortality. Prompt diagnosis and referral to a specialist center is paramount. The number of operations conducted in England has doubled in 10 years and the associated survival following surgery has improved. Regional variations exist in service provision with a trend towards better survival in high volume centers.

Transapical perfusion for peri-arrest salvage during transcutaneous aortic valve implantation

An 80-year-old man developed severe haemodynamic instability during a transapical aortic valve implantation. He was not suitable for a conventional surgical approach due to comorbidities and patent aortocoronary bypass grafts also limited further stabilizing actions. As a bail-out procedure, we demonstrate the feasibility of transapical arterial cannulation by crossing a newly implanted TAVI valve in order to establish an emergency bypass circuit

Management options for aorto-oesophageal fistula: case histories and review of the literature

OBJECTIVE

An aorto-oesophageal fistula is a rare clinical entity, leading to life-threatening gastrointestinal bleeding. Thoracic aortic aneurysms are the most common cause of aorto-oesophageal fistulae; further causes involve foreign body ingestion, trauma (in most cases iatrogenic), carcinoma or, very rarely, aortitis tuberculotica.

METHODS

Due to its rarity, there are no large multicentre studies present to evaluate the efficacy of different therapeutic management options. Since it is associated with significant morbidity and mortality, we give a short summary of various treatment approaches performed in our clinical practice in the past three years. The most straightforward therapeutic option may be an endovascular aortic repair and subtotal oesophageal resection followed by gastro-oesophageal reconstruction, but other alternative treatment possibilities are also present, although with probable higher morbidity.

CONCLUSIONS

Eliminating the source of bleeding as an emergency, resecting the oesophagus urgently to prevent sepsis and reconstructing the gastrointestinal continuity as an elective case after having the inflammatory processes settled seems to justify the endovascular aortic repair and subtotal oesophageal resection, followed by a gastro-oesophageal reconstruction, as an effective surgical approach.

Emergency intensive care admission following elective thoracic surgery

AIM

The aim of this study was to analyse the outcomes of patients admitted to the intensive care unit (ICU) following initial recovery after elective thoracic surgery.

METHODS

The case notes of all patients who underwent elective thoracic surgery over a one-year period were reviewed. Patients who were admitted to ICU following an initial recovery on the ward were identified and their postoperative course analysed. The clinical and demographic characteristics of these patients were recorded and their outcomes analysed.

RESULTS

A total of 20 patients were admitted to ICU of whom 13 (65%) were admitted for respiratory complication, 5 with sepsis and 2 with cardiovascular instability. Sixteen (80%) patients required CPAP or BIPAP, of whom only 7 (35%) required mechanical ventilation. Renal support was required in 7 patients, with 2 (10%) requiring haemofiltration. ICU survival was 15 patients (75%), whilst overall three-month survival post ICU admission was 65%. Requirement for renal support was the only predictor of mortality on univariate and multivariate analysis.

CONCLUSIONS

Salvage ICU admission following elective thoracic surgery is associated with significant mortality, however the outcome is far from hopeless. The majority of patients can be managed without recourse to mechanical ventilation or haemofiltration. The need for renal support is, however, a significant adverse prognostic indicator.

All delays before radiotherapy risk progression of Merkel cell carcinoma

Prolonged waiting times for radiotherapy have resulted in many centres assigning priorities to various patient or diagnostic groups. A high risk of progression on a waiting list is one factor that would reasonably influence the priority. The present descriptive study of 27 patients with Merkel cell carcinoma (MCC) found that a median wait of 24 days for radiotherapy is associated with a high risk of progression. Eleven (41%) of 27 patients developed progressive disease, including five (45%) of 11 patients waiting for adjuvant radiotherapy. Patients treated adjuvantly also had longer waiting times prior to their initial radiotherapy consultation (median 41 days), which may have contributed to the rate of progression. Merkel cell carcinoma is an aggressive but curable malignancy and appropriate management should include efforts to minimize all potential delays prior to the commencement of radiotherapy.

Pericardial mesothelioma following mantle field radiotherapy

A 49-year-old female was referred with recurrent pericardial effusion following mantle field radiotherapy for Hodgkin s lymphoma. She underwent video-assisted thoracoscopy and resection of a pericardial window. Intraoperatively she suffered a cardiac arrest and subsequently died in the early postoperative period despite maximal therapy. Pathological examination revealed extensive myocardial fibrosis and multiple nodules of pericardial mesothelioma. The latter has hitherto not been recognised following mediastinal radiation. The cardiac complications of mantle field radiotherapy are discussed.

Acute pulmonary thromboembolism complicating pneumonectomy: successful operative management

Pulmonary thromboembolism after pneumonectomy carries high fatality. Here we present a case of acute embolism to the left pulmonary artery with thrombus in the right atrium and inferior vena cava following right pneumonectomy. Diagnosis was made clinically and radiologically before proceeding to emergency surgery. Thromboembolectomy was successfully performed on cardiopulmonary bypass and the patient was subsequently discharged home after uneventful recovery.

Drosophila p53 binds a damage response element at the reaper locus

The tumor suppressor gene p53 regulates multiple cellular responses to DNA damage, but the transcriptional targets that specify these responses are incompletely understood. We describe a Drosophila p53 homolog and demonstrate that it can activate transcription from a promoter containing binding sites for human p53. Dominant-negative forms of Drosophila p53 inhibit both transactivation in cultured cells and radiation-induced apoptosis in developing tissues. The cis-regulatory region of the proapoptotic gene reaper contains a radiation-inducible enhancer that includes a consensus p53 binding site. Drosophila p53 can activate transcription from this site in yeast and a multimer of this site is sufficient for radiation induction in vivo. These results indicate that reaper is a direct transcriptional target of Drosophila p53 following DNA damage.

mus304 encodes a novel DNA damage checkpoint protein required during Drosophila development

Checkpoints block cell cycle progression in eukaryotic cells exposed to DNA damaging agents. We show that several Drosophila homologs of checkpoint genes, mei-41, grapes, and 14-3-3epsilon, regulate a DNA damage checkpoint in the developing eye. We have used this assay to show that the mutagen-sensitive gene mus304 is also required for this checkpoint. mus304 encodes a novel coiled-coil domain protein, which is targeted to the cytoplasm. Similar to mei-41, mus304 is required for chromosome break repair and for genomic stability. mus304 animals also exhibit three developmental defects, abnormal bristle morphology, decreased meiotic recombination, and arrested embryonic development. We suggest that these phenotypes reflect distinct developmental consequences of a single underlying checkpoint defect. Similar mechanisms may account for the puzzling array of symptoms observed in humans with mutations in the ATM tumor suppressor gene.

An exploration of the sequence of a 2.9-Mb region of the genome of Drosophila melanogaster: the Adh region

A contiguous sequence of nearly 3 Mb from the genome of Drosophila melanogaster has been sequenced from a series of overlapping P1 and BAC clones. This region covers 69 chromosome polytene bands on chromosome arm 2L, including the genetically well-characterized "Adh region." A computational analysis of the sequence predicts 218 protein-coding genes, 11 tRNAs, and 17 transposable element sequences. At least 38 of the protein-coding genes are arranged in clusters of from 2 to 6 closely related genes, suggesting extensive tandem duplication. The gene density is one protein-coding gene every 13 kb; the transposable element density is one element every 171 kb. Of 73 genes in this region identified by genetic analysis, 49 have been located on the sequence; P-element insertions have been mapped to 43 genes. Ninety-five (44%) of the known and predicted genes match a Drosophila EST, and 144 (66%) have clear similarities to proteins in other organisms. Genes known to have mutant phenotypes are more likely to be represented in cDNA libraries, and far more likely to have products similar to proteins of other organisms, than are genes with no known mutant phenotype. Over 650 chromosome aberration breakpoints map to this chromosome region, and their nonrandom distribution on the genetic map reflects variation in gene spacing on the DNA. This is the first large-scale analysis of the genome of D. melanogaster at the sequence level. In addition to the direct results obtained, this analysis has allowed us to develop and test methods that will be needed to interpret the complete sequence of the genome of this species. Before beginning a Hunt, it is wise to ask someone what you are looking for before you begin looking for it. Milne 1926

Comparison of primary coronary artery bypass surgery in a British Indo-Asian and white Caucasian population

AIM

To compare the clinical characteristics, at the time of admission and after coronary revascularization by bypass surgery, among British patients of Indo-Asian and white Caucasian descent.

METHOD

One hundred and ninety-four pairs of patients admitted between November 1994 and January 1997 were matched for age (within 3 years), sex and date of admission (within 3 months). Their clinical characteristics at the time of admission for coronary artery bypass grafting surgery, and the incidence of hospital morbidity, hospital mortality and length of stay in the intensive therapy unit or hospital following coronary artery bypass grafting were determined.

RESULTS

A higher proportion of Indo-Asian patients underwent coronary revascularization on a non-elective basis (43% vs 32% white Caucasian patients, P =0.018), had a higher prevalence of diabetes (39% vs 12%, P =0.0001), a lower prevalence of smoking (36% vs 80%, P =0.0001) and a lower rate of previous myocardial infarction (47% vs 62%, P =0.012). As regards revascularization, although there was no significant difference in the number of vessels revascularized, there was a lower use of the arterial conduit (internal mammary artery) in the Indo-Asian patients (72% vs 81%, P =0.028) particularly for those undergoing emergency/urgent surgery (59% vs 72%, P =0.001) and with a previous myocardial infarction (65% vs 81%;P =0.01) when compared with their white Caucasian counterparts. Following surgery there were no differences in the types of support required for vital functions. There was no significant difference in the proportion of major post-operative complications, that is, haemorrhage, cerebrovascular accident, renal failure requiring dialysis or respiratory failure. Similarly, there were no differences in the length of intensive therapy unit stay (median stay 1 day vs 1 day, P =0.4) and hospital stay following surgery (median stay 6 days vs 6 days, P =0.5) between the two groups. Although there was a trend towards a higher in-hospital (30 day) mortality (6.7% [95% confidence intervals CI 3.18-10.21] vs 2.6% [CI 0.35-4.9;P =0.0618]), in Indo-Asians compared to white Caucasians this trend disappeared when patients in the two groups undergoing non-elective surgery only were compared (9% vs 7%;P =0.7).

CONCLUSIONS

A higher proportion of Indo-Asians underwent non-elective coronary revascularization, with a significantly lower use of the arterial conduit and a relatively higher in-hospital mortality. Following coronary revascularization the medical management, length of stay and hospital morbidity in Indo-Asian patients was no different from that of their white Caucasian counterparts. This is despite a perceived poorer outcome in Indo-Asians compared to white Caucasians.

The threshold for air leak: stapled versus sutured human bronchi, and experimental study

BACKGROUND

Little is known about the integrity of staple-closure of the bronchus and its tolerance to normal mechanical stresses (cough, sneezing, etc.) in the immediate early post-operative period. There are few studies which tested the mechanical strength of stapled bronchial closure compared with manually closed bronchi using the threshold for fluid leak across the bronchial suture line which differs from air.

MATERIAL AND METHODS

Intact cadaveric tracheobronchial tree (n = 40) were selected, age range from 55 to 70, of which 60% were males. They were divided into two groups: group A, 20 left bronchi were closed with RLV 30 Ethicon 4.8 mm bronchial stapler; group B, 20 were closed with 4 0 Prolene simple interrupted sutures. All specimens were intubated with endotracheal tube and submerged under water before testing the immediate air leak with the standard 40 mm Hg inflation pressure. Inflation pressure was increased until air leak was detected. The stapled closures were resected and subjected to radiological examination.

RESULTS

No air leak was detected in any bronchus at 40 mmHg regardless of the closure technique. The median leakage pressure was significantly higher in the hand sutured bronchi compared to the stapled group (200 vs. 105 mmHg, respectively) and 50% (n = 10) leaked from multiple sites in the stapled group compared with leakage from one site only in group B, this difference was statistically significant P < 0.001. The radiological appearance of the staples maintained the B configuration, recommended by the manufacturer as a sign of sound application.

CONCLUSION

Hand sutured bronchi tolerated higher inflation pressure compared with the stapled ones before leaking air. Air leak at high pressure occurs in the presence of intact staples.

von Willebrand factor and urinary albumin excretion are possible indicators of endothelial dysfunction in cardiopulmonary bypass

OBJECTIVE

Experimental evidence suggests that cardiopulmonary bypass (CPB) associated inflammatory response leads to endothelial injury and increased permeability, but this has been difficult to show clinically. We have investigated the use of von Willebrand factor (vWF), and urinary albumin excretion, as measured by the urinary albumin creatinine ratio (ACR), to demonstrate this.

METHODS

A total of 23 patients undergoing elective coronary artery bypass grafting were studied. Complement fragment C3a, leukotrienne B4 (LTB4), interleukin 6 (IL6), neutrophil elastase, vWF and ACR were measured on anaesthetic induction (baseline), 20 min after starting CPB, 5 min after cross-clamp removal, 5 min, 2, 6 and 24 h after termination of CPB. Anaesthetic, CPB and myocardial protection techniques were standardised. ANOVA was performed by using the distribution free Friedman test for each measured parameter. When significance differences were found (P < 0.05), post hoc analysis with Wilcoxon signed rank test was used for comparison of each time point with the base line level and differences were only accepted as significant following the Bonferroni correction (P < 0.008). Summary measures of peak versus peak and area under the cure were also analysed for ACR with vWF.

RESULTS

Peak vs. baseline levels for C3a were 4.9 vs. 2.1 microg/ml (P < 0.0001), LTB4 was 800 vs. 20 pg/ml (P < 0.0001), neutrophil elastase was 250 vs. 115 ng/ml (P < 0.001), IL6 was 620 vs. 1.4 pg/ml (P < 0.0001), vWF was 2.2 vs. 1.3 IU/ml (P < 0.0001) and ACR was 17.6 vs. 2.0 mg/mmol (P < 0.0001). C3a, LTB4 and ACR peaked during the operation. Neutrophil elastase peaked at 2 h following CPB. IL6 and vWF peaked at 6 h following CPB. The correlation coefficient between vWF and ACR following peak versus peak analysis was 0.48 (P = 0.035), and area under the curve analysis was 0.6 (P < 0.01).

CONCLUSION

These results demonstrate that endothelial permeability and injury, as measured by urinary albumin excretion and vWF, respectively, are related and the use of these easily detectable and sensitive biochemical markers warrants further investigation.

Is there a role for video-assisted thoracoscopy in the staging of non-small cell lung cancer?

OBJECTIVE

To evaluate the role of video-assisted thoracoscopy (VAT) in the staging of non-small cell lung cancer (NSCLC).

METHODS

In 30 patients (18 male, 12 female, median age 62 (50-78) years) VAT was used to assess the operability of NSCLC in cases where doubt existed after conventional staging investigations had been performed.

RESULTS

VAT was used to assess direct tumour invasion of adjacent organs in 17 patients (mediastinal invasion in 14 and chest wall invasion in 3 patients). In 4 patients with limited respiratory reserve, VAT confirmed the need only for lobectomy prior to thoracotomy. Mediastinal lymph node biopsy was performed in 5 patients with significant (> 1.5 cm) lymphadenopathy on CT scan. VAT was also used to assess bilateral lesions in 4 patients with suspected synchronous tumours. Conversion to thoracotomy was necessary in 4 patients for technical reasons. Successful resection was possible in 17 of the remaining 26 cases, while unnecessary thoracotomy was avoided in 9 patients (30%) with unresectable or benign disease. In 4 patients deemed inoperable on CT scan, VAT staging enabled subsequent resection.

CONCLUSIONS

Video-assisted thoracoscopy appears to have a complementary role in staging NSCLC when other methods are equivocal. It has the potential for increased sensitivity over conventional staging methods.

Pentoxifylline preloading reduces endothelial injury and permeability in cardiopulmonary bypass

Pentoxifylline (PTX), a methyl xanthine derivative, reduces endothelial permeability. A double blind, prospective, randomized, placebo controlled, parallel study was undertaken to assess the effect of PTX on leukotriene B4, complement fragment C3a, interleukin 6 (IL6), endothelial injury as measured by von Willebrand factor (vWf), and endothelial permeability as measured by urinary albumin excretion (expressed as excreted urinary albumin to creatinine ratio [ACR]) in patients undergoing cardiopulmonary bypass (CPB) for elective coronary artery bypass grafting. Twenty patients were recruited into each treatment arm and given either PTX 400 mg or placebo three times daily for 1 week before surgery. Patients were well matched. All operations were performed using one anesthetic, CPB, and a myocardial protection technique. Blood and urine samples were taken after anesthetic induction (baseline); 20 min after the start of CPB; 5 min after removal of the cross clamp; and 5 min and 2, 6, and 24 hr after the end of CPB. Pentoxifylline did not reduce IL6, C3a, and LTB4 release but reduced Factor VIIIRAg and urinary albumin excretion preoperatively (PTX vs placebo, ACR 1q.0 vs 2.1 mg/mmol, vWf 0.8 vs 1.3 IU/ml, p < 0.05) and peak levels (PTX vs placebo, ACR 8.9 vs 16.2, vWf 1.2 vs 2.2, p < 0.05) after CPB. These results suggest that PTX may attenuate the endothelial injury and permeability seen in CPB.

Hemofiltration in a cardiac intensive care unit: time for a rational approach

The typical annual expenditure for patients requiring continuous hemofiltration (CHF) is high. To audit the benefit of this expensive treatment, the outcome of 48 consecutive patients (34 men, 14 women; mean age, 65 years) requiring hemofiltration for acute renal failure was analyzed during a period of 24 months. The operations performed were 26 CABG, 8 AVR, 3 AVR/MVR, 2 post infarction VSD repairs, and 1 thoracoabdominal aneurysmectomy. Indications for hemofiltration were oliguria and fluid overload in 69%, uremia in 56%, acidosis in 33%, and hyperkemia in 13%. Twenty five patients (52%) died while in the hospital, and 10 more died within 9 months of discharge. Of the remaining 13 survivors, 6 (46%) were classified as III or IV according to the New York Heart Association classification system. The mean ITU and hospital stay per patient requiring CHF was 15.3 days and 25.4 days, respectively. There were no statistically significant differences between patients who did and did not survive in the hospital in age, pre-operative renal function, ejection fraction, duration of cardiopulmonary bypass, or urine output before CHF. However, there were no survivors when the cardiac index was less than 1.7 L/m2 and adrenalin requirement was more than 30 micrograms/min before CHF (seven patients). These results suggest that the short- and long-term outcome in patients requiring CHF after cardiac surgery is poor. Considering the large demand on resources, the use of CHF should be rationalized, particularly in patients with persistent low cardiac output.

Retrograde cerebral perfusion: clinical experience in emergency and elective aortic operations

We recently have used retrograde cerebral perfusion via the superior vena cava in association with hypothermic circulatory arrest as an adjunct to cerebral protection during aortic arch operations. Between April 1993 and March 1994, 23 patients (14 male; 9 female; median age, 64 years; age range, 25 to 76 years; 14 emergency, 9 elective) underwent operation on the ascending aorta, aortic arch, or both for acute dissection (11) or aneurysm (12). Aortic root replacement was performed in 13 patients (7 with arch replacement), ascending aortic replacement in 7 (4 with arch replacement), isolated aortic arch replacement in 2, and repair of sinus of Valsalva aneurysm in 1. Coronary artery bypass grafting was performed in 4 patients. Hypothermic circulatory arrest (15 degrees C) and retrograde cerebral perfusion were implemented in all cases (median circulatory arrest time, 21 minutes; range, 13 to 51 minutes; median retrograde cerebral perfusion time, 20 minutes; range, 12 to 50 minutes). Three hospital deaths occurred (atheromatous embolic stroke, sepsis, rupture of infrarenal aortic aneurysm). The remaining patients had no neurologic damage (median intensive therapy unit stay, 1 day; range, 1 to 5 days). Retrograde cerebral perfusion is easy to establish and safe, and may improve brain protection during hypothermic circulatory arrest.

Anomalous aortic origin of the right coronary artery. An unusual cause of angina pectoris and its surgical correction

A 45-year-old female presented with typical recent-onset exertional angina pectoris. Subsequent investigation showed that the likely cause was an aberrant origin of the right coronary artery arising from the left coronary sinus. This anomaly is uncommon and is not usually associated with angina pectoris. Surgical rerouting of the origin of the right coronary artery produced complete resolution of ischaemia.

Chronic muscle stimulation improves ischaemic muscle performance in patients with peripheral vascular disease

There is currently no established treatment for intermittent claudication with proven long term benefit. Exercise classes have been shown to improve walking distance. Chronic electromyostimulation (CEMS) a method of stimulating skeletal muscle has effects on normal muscle which may also benefit claudicants. We investigated the effects of one month of CEMS on claudicants in a single blind placebo controlled study. Patients were randomised to either CEMS (treatment) or transcutaneous nerve stimulation (TENS) placebo. The effects of the two modalities were assessed using the conventional measures of claudicating distance (CD), maximum walking distance (MWD), ankle-brachial pressure index (ABPI) and pressure recovery time (PRT). Muscle performance was assessed by the fatigue index (FI) a technique determining the decrease in ischaemic muscle response to repeated contraction. After 4 weeks treatment the CEMS group showed significant improvements in their median CD (88 to 111) and MWD (118 to 158); this was not seen in the control group. Muscle performance also increased significantly during the 4 weeks of treatment in the CEMS group but not in the control group. These changes were not maintained after CEMS was stopped. This pilot study suggests that CEMS may well have a role to play in the treatment of intermittent claudication though a number of further studies need to be undertaken.

Pharmacological reduction of the systemically damaging effects of local ischaemia

Many patients with intermittent claudication are encouraged to exercise. However, transient exercise-induced muscle ischaemia results in systemic vascular endothelial injury associated with increased vascular permeability manifest as an increase in urinary albumin excretion. Repetitive systemic vascular endothelial injury leads to accelerated atherogenesis and may explain the high cardiovascular mortality rate of claudicants. Oxpentifylline, a haemorheological agent, has recently been shown to prevent vascular endothelial injury in animal models. A double-blind, placebo-controlled, cross-over trial was undertaken to determine the effect of oxpentifylline on exercise-induced systemic vascular endothelial injury in 20 claudicants. Urinary albumin, expressed as a creatinine ratio (ACR), was measured before and 1 and 2 hours after standardised exercise following 1 week treatment with either active drug or placebo. Oxpentifylline reduced the median (range) 1 hour post exercise increase in ACR from 0.35 (-0.46-12.72) to 0.02 (-6.00-14.10) mg/mmol. (p = 0.030, z = 2.2 Wilcoxon rank sign test). These results confirm that local ischaemia is associated with a potentially deleterious systemic effect and that it may be possible to attenuate this pharmacologically. The clinical significance of this is yet to be determined.

Sports causing most injuries in Hong Kong

A prospective survey was carried out on 2293 patients attending the Sports Injury Clinic in the Prince of Wales Hospital between May 1984 and December 1990. A Sports Injury Report Form was completed for each patient. Subjects in this study represent a group of nonprofessional and non-élite athletes in a metropolitan area. Soccer, basketball, volleyball, long-distance running and cycling in descending order were the five most common sports causing injury. Different sports produced different injury patterns. In four of the five sports, the knee (27.27-50.47%) and the ankle (16.78-24.67%) were the commonest sites of injury. In cycling, the face (19.46%) was the commonest site of injury. There was a higher injury rate to the lower than the upper limb in soccer, basketball, volleyball and long-distance running, with a ratio of upper- to lower-limb injury ranging from 1:1.13 to 1:46.10. In cycling, upper limb injury was more frequent (upper- to lower-limb injury ratio was 1:0.53). Sprain was the commonest injury overall (44.60%). It was also the commonest injury condition in volleyball (55.15%), basketball (55.34%), soccer (51.41%) and long-distance running (39.33%). In cycling, abrasion (24.83%) was commonest.

Respiratory changes and structure of sleep in young high-altitude dwellers in the Andes of Peru

Sleep organisation in eight young [mean (SD); 20.9 (2.6) years] Peruvian high-altitude residents was studied in a laboratory in Cerro de Pasco at 4300 m. Electroencephalograms, electromyograms, electro-oculograms, electrocardiograms, respiratory movements and arterial oxygen saturation were recorded on an 8-channel Medilog recorder and analysed later in England. Haematocrits ranged from 48% to 64% [57.9 (5.6)%]. The amount of slow wave rapid eye movement (REM) sleep was similar to that reported in young lowlanders sleeping at sea level but very different to the disturbed sleep in visitors sleeping at high altitude. All the Peruvians showed episodes of periodic breathing and respiratory apnoeas [29 (15) night-1] resulting in marked arterial oxygen desaturation [81 (4.5)%; changes of 6 (2.5)%]. These events occurred either during stage 2 or REM sleep and were more frequent in those with lower haematocrits. The amount of wakefulness during the night was 2-3 times greater than would be expected in an age-matched lowland population at sea level. The awakenings were strongly associated with apnoeas (P < 0.02) but were negatively correlated with haematocrit, although this was only significant for seven of the subjects (P < 0.05).

Adjuvant prostanoid treatment during femorodistal reconstruction

A prospective randomized placebo-controlled trial was conducted to determine the effects of the stable prostacyclin analogue iloprost on early graft patency and hemodynamic parameters during femorodistal reconstruction for critical leg ischemia. Peripheral resistance and graft blood flow were measured using an operative Doppler flowmeter and graft pressure transducer. Postoperative graft surveillance was continued at 1-month and then at 3-month intervals by duplex Doppler ultrasonography, measurement of ankle-brachial pressure indices, and intravenous digital subtraction angiography when indicated. In patients receiving 3000 ng of iloprost (n = 45) infused into the graft on completion there was an immediate mean decrease in peripheral resistance of 44% that persisted to skin closure in comparison with controls (n = 38) in whom no such decrease in resistance occurred (p < 0.001, Wilcoxon test). During the same period, mean graft blood flow increased in iloprost-treated patients by 74.5% compared with controls in whom there was a 6% increase in flow (p < 0.001). Primary cumulative patencies at 1 month were significantly higher in iloprost-treated grafts, 98% compared to 83% for controls (p < 0.05, log-rank test). Cumulative primary patencies at 1 year and secondary patencies at 1 month and 1 year were also greater in the iloprost-treated group (67%, 98%, and 87.6%, respectively) compared to controls (65%, 86%, and 79.3%, respectively), but these did not achieve statistical significance. A single bolus infusion of iloprost has prolonged beneficial effects on graft blood flow and peripheral resistance during femorodistal reconstruction. This is reflected by improved early primary graft patencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Reperfusion plasma contains a neutrophil activator

Aortic aneurysm repair produces inflammatory mediators, neutrophil activation, and remote organ injury. Reperfusion plasma from these patients produces microvascular injury in an ex vivo chemotactic model. This study investigates the mechanism of this injury. Vena caval blood was obtained before and 15 minutes after aortic clamp removal (n = 16) or at laparotomy (n = 10). Plasma or saline solution was introduced into unit dose chambers fixed atop dermabrasions on the back of depilated anesthetized rabbits. Animals were treated with intravenous saline solution (n = 4); made neutropenic with nitrogen mustard (n = 4); pretreated with the xanthine oxidase inhibitor allopurinol (n = 4); or cotreated intravenously with the free radical scavengers superoxide dismutase (SOD) and catalase (n = 4). Three hours later neutrophil counts (polymorphonuclear cells [PMN]/mm3) and activity (free radical production by flow cytometry), protein leakage, and inflammatory mediators (thromboxane [TX] and leukotriene B4 [LTB4]) were measured. In contrast to control plasma in untreated rabbits, reperfusion plasma produced TX and LTB4 generation (1090 +/- 105 and 794 +/- 91 pg/ml, respectively, p < 0.01), PMN accumulation (1636 +/- 210/mm3, p < 0.01) and activation (276 +/- 31 mean fluorescent units), and microvascular permeability (554 +/- 90 micrograms/ml, p < 0.01). Neutropenia (3 +/- 1 PMN/mm3) and cotreatment with SOD and catalase abolished these responses, whereas pretreatment with allopurinol did not. Human reperfusion plasma contains a soluble factor that stimulates free radical generation by rabbit neutrophils to produce a microvascular injury characterized by de novo TX production, neutrophil accumulation and activation, and increased microvascular permeability to protein.

Iloprost reduces peripheral resistance during femoro-distal reconstruction

A randomised placebo-controlled trial was conducted to investigate the effect of iloprost, a stable prostacyclin mimetic, on peripheral resistance during femoro-distal bypass. Patients undergoing femoro-distal long saphenous vein bypass for critical ischaemia received 3000 ng of iloprost or placebo infused into the graft via an unligated side branch over 2 min. Graft blood flow and peripheral resistance were measured for 20 min, using an operative Doppler flowmeter (OpDop 130, SciMed, U.K.) and a pressure transducer to record graft pressure. Postoperatively, graft blood flow was assessed by daily duplex ultrasound for 7 days. Iloprost produced an immediate drop in peripheral resistance in all cases (n = 18) by a mean (range) of 40% (4-80%) compared with controls (n = 15) in whom there was a 5.3% (-8 to +36%) increase in resistance (p less than 0.01, Wilcoxon test). Decreased peripheral resistance in iloprost-treated patients persisted to 20 min. The largest decreases in peripheral resistance occurred in patients with the highest initial resistances (r = 0.56, p less than 0.02). Graft flow during the same period increased by 52% (-7 to 294%) compared with controls in whom there was a 6% (-17 to 26%) increase in flow, (p less than 0.01). Flow remained elevated by 53% over baseline values at 1 week post-infusion in the iloprost-treated group but this did not achieve statistical significance compared to controls in whom flow also increased by 13%. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

The practice of cardiothoracic surgeons in the perioperative staging of non-small cell lung cancer

BACKGROUND

The treatment and prognosis of non-small cell lung cancer, and assessment of the results of treatment, depend on accurate perioperative staging. The extent to which this is carried out in the United Kingdom is unknown.

METHODS

A postal questionnaire survey was undertaken in 1990 to determine the perioperative staging practices of cardiothoracic surgeons in the United Kingdom.

RESULTS

Replies from 77 surgeons, who between them performed about 4833 pulmonary resections a year for lung cancer, were analysed. Forty four per cent of surgeons, operating on 43% of the patients, do not perform computed tomography of the thorax or mediastinal exploration before surgery. They may therefore embark on a thoracotomy for stage III disease. At thoracotomy 45% of surgeons, operating on 40% of patients, do not sample macroscopically normal lymph nodes. They may therefore understage cases as N0/N1 when there is at least microscopic disease in mediastinal lymph nodes.

CONCLUSIONS

The staging of lung cancer in the United Kingdom in 1990 appears in many instances to be inadequate. There should be a more organised approach to perioperative staging so that prognosis may be assessed and comparisons between groups of patients can be made.

Sleep of Andean high altitude natives

The structure of sleep in lowland visitors to altitudes greater than 4000 m is grossly disturbed. There are no data on sleep in long-term residents of high altitudes. This paper describes an electroencephalographic study of sleep in high altitude dwellers who were born in and are permanent residents of Cerro de Pasco in the Peruvian Andes, situated at 4330 m. Eight healthy male volunteers aged between 18 and 69 years were studied. Sleep was measured on three consecutive nights for each subject. Electroencephalographs, submental electromyographs and electro-oculograms were recorded. Only data from the third night were used in the analysis. The sleep patterns of these subjects resembled the normal sleep patterns described by others in lowlanders at sea level. There were significant amounts of slow wave sleep in the younger subjects and rapid eye movement sleep seemed unimpaired.

Failed femorocrural reconstruction does not prejudice amputation level

From January 1985 to December 1989, 500 consecutive patients presented to a single vascular unit with limb-threatening acute or critical ischaemia. Vascular reconstruction was attempted unless the patient had insufficient viable tissue to permit weight bearing or complete absence of run-off vessels in the calf. Fifty patients underwent a primary amputation and 450 patients underwent vascular reconstruction, of whom 265 had a femorocrural bypass. Sixty secondary amputations were performed following femorocrural bypass failure. The below-knee amputation to above-knee amputation ratio (BKA:AKA) was 2.0 in the primary amputation group and 1.1 in the secondary amputation group. Direct comparison between the two groups is not valid as they are clinically different. The combined BKA:AKA ratio was 1.4. This compares favourably with the BKA:AKA ratio of recent published series and figures from the National Amputation and Limb Fitting Services. It suggests that an unselective policy of vascular reconstruction for critical ischaemia does not lead to a higher proportion of above-knee amputations.