Minimally Invasive Versus Conventional Aortic Valve Replacement: A Propensity-Matched Study From the UK National Data.

OBJECTIVE: Minimally invasive aortic valve replacement (MIAVR) has been demonstrated as a safe and effective option but remains underused. We aimed to evaluate outcomes of isolated MIAVR compared with conventional aortic valve replacement (CAVR). METHODS: Data from The National Institute for Cardiovascular Outcomes Research (NICOR) were analyzed at seven volunteer centers (2006-2012). Primary outcomes were in-hospital mortality and midterm survival. Secondary outcomes were postoperative length of stay as well as cumulative bypass and cross-clamp times. Propensity modeling with matched cohort analysis was used. RESULTS: Of 307 consecutive MIAVR patients, 151 (49%) were performed during the last 2 years of study with a continued increase in numbers. The 307 MIAVR patients were matched on a 1:1 ratio. In the matched CAVR group, there was no statistically significant difference in in-hospital mortality [MIAVR, 4/307,(1.3%); 95% confidence interval (CI), 0.4%-3.4% vs CAVR, 6/307 (2.0%); 95% CI, 0.8%-4.3%; P = 0.752]. One-year survival rates in the MIAVR and CAVR groups were 94.4% and 94.6%, respectively. There was no statistically significant difference in midterm survival (P = 0.677; hazard ratio, 0.90; 95% CI, 0.56-1.46). Median postoperative length of stay was lower in the MIAVR patients by 1 day (P = 0.009). The mean cumulative bypass time (94.8 vs 91.3 minutes; P = 0.333) and cross-clamp time (74.6 vs 68.4 minutes; P = 0.006) were longer in the MIAVR group; however, this was significant only in the cross-clamp time comparison. CONCLUSIONS: Minimally invasive aortic valve replacement is a safe alternative to CAVR with respect to operative and 1-year mortality and is associated with a shorter postoperative stay. Further studies are required in high-risk (logistic EuroSCORE > 10) patients to define the role of MIAVR.

Speeding dantrolene preparation for treating malignant hyperthermia.

Dantrolene is known to have a low solubility in water Studies have demonstrated that it dissolves more rapidly in warm water However, the overall benefit of warming has not been measured. This study evaluated the overall time benefit of warming. The first step was to measure how long it took to warm the 10 ml plastic ampoules of sterile water from ambient temperature (20 degrees C) to 45 degrees C. We found that when immersed in a water bath held at 45 degrees C, this required a minimum of seven minutes. Therefore the ampoules used for the study were kept immersed in a water bath held at 45 degrees C for at least 10 minutes. It took an average of 82.6 seconds to draw 60 ml (six ampoules) of water into a 60 ml syringe. Squirting the water into the dantrolene vial and miring until dissolved took 102.8 seconds (SD 8.3) for the warmed water and 129.0 seconds (SD 14.6) for the ambient temperature water (P = 0.009). Redrawing the dantrolene solution into the syringe took an average of 32 seconds for the warmed water and 35.2 seconds for the ambient temperature water. After the redrawing phase the average temperature of the warmed solution was 32.2 degrees C. The average total preparation time for the warmed solution was 217.4 seconds (SD 20.0) and for the ambient temperature preparation was 243.0 seconds (SD 11.7) (P = 0.038). Thus the time difference in preparation was about 256 seconds, which is the time that could be saved in preparing the standard dose of 10 vials of dantrolene using water at 45 degrees C. However, as it required about seven minutes to initially warm the sterile ampoules, there would be a net increase, not decrease in the time required. These findings indicate that warming is of no benefit in speeding dantrolene preparation.

Omni-Stat (Chitosan) arrests bleeding in heparinised subjects in vivo: an experimental study in a model of major peripheral vascular injury.

OBJECTIVE: To explore the effectiveness of Omni-Stat (Chitosan) in a model of major haemorrhage in the presence of clotting dysfunction. METHOD: A total of 12 major femoral artery bleeds in moderately heparinised swine treated with Omni-Stat (Chitosan) were compared with five control bleeds. RESULTS: Haemostasis was successfully achieved at first treatment in 10 of 12 bleeds and at second treatment in the remaining two bleeds. CONCLUSION: The study supports the evidence that Omni-Stat (Chitosan) acts independently of classical clotting pathways and should be effective in patients with clotting dysfunctions, who suffer major haemorrhage. It also suggests the potential for a role in cardiac surgery.

A new hemostatic agent: initial life-saving experience with Celox (chitosan) in cardiothoracic surgery.

Celox (MedTrade Products Ltd, Cheshire, UK) is a proprietary preparation of chitosan, indicated for moderate to severe hemorrhage and currently used for hemostasis in the emergency and military settings. We describe its lifesaving use in 2 patients undergoing cardiothoracic surgery in which conventional techniques had failed.

Modifiable risk factors remain significant causes of medium term mortality after first time Coronary artery bypass grafting.

BACKGROUND: Whilst there is much current data on early outcomes after Coronary artery bypass grafting(CABG), there is relatively little data on medium term outcomes in the current era. The purpose of this study is to present a single surgeon series comprising of all first time CABG patients operated on with the technique of cross clamp fibrillation from Feb-1996 to through to Jan-2003, and to seek risk factors for medium term mortality in these patients. METHODS: Data was collected from Hospital Episode Statistics and departmental patient administration and tracking systems and cross checked using database techniques. Patient outcomes were searched using the National Health Service strategic tracing service. RESULTS: Mean follow up was 5.3 years(0-9.4 years) and was complete for all patients. 30-day survival was 98.4%, 1-year survival 95% and 8-year survival 79%. Cox-regression analysis revealed that several modifiable pre-operative risk factors remain significant predictors of medium term mortality, including Diabetes(Hazard Ratio(HR) 1.73, 95%CI 1.21-2.45), Chromic obstructive pulmonary disease(HR 2.02, 95%CI 1.09-3.72), Peripheral vascular disease(HR 1.68, 95%CI 1.13-2.5), Body mass index>30(HR 1.54, 95%CI 1.08-2.20) and current smoker at operation(HR 1.67, 95%CI 1.03-2.72). However hypertension(HR 1.31, 95%CI 0.95-1.82) and Hypercholestrolaemia(HR 0.81, 95%CI 0.58-1.13) were not predictive which may reflect adequate post-operative control. CONCLUSION: Coronary artery bypass surgery using cross clamp fibrillation is associated with a very low operative mortality. Medium term survival is also good but risk factors such as smoking at operation, Chronic obstructive pulmonary disease, obesity and diabetes negatively impact this survival and should be aggressively treated in the years post-surgery.

Surgical resection of melorheostosis in the ribs.

Melorheostosis is a rare nongenetic developmental anomaly of the cortical bone. We present a 40-year-old woman who was diagnosed with melorheostosis affecting the ribs only. Chronic pain and cosmetic deformity were her presenting symptoms. She underwent posterolateral thoracotomy and excision of the affected ribs, with a satisfactory outcome of this uncommon presentation.

Pseudoanaphylaxis.

Profound hypotension and cardiac arrest after commencement of combined spinal and general anaesthesia in a patient for knee replacement surgery raised the suspicion of anaphylaxis. This seemed to be confirmed when a mast cell tryptase test taken about 90 minutes after the onset of the hypotension was elevated. However, subsequent intradermal skin testing twelve weeks later did not identify a causal drug. Repeat mast cell tryptase at the time showed the same elevation, which led to the correct diagnosis of mastocytosis and a secondary diagnosis that the patient's hypotension and cardiac arrest were the result of her spinal anaesthesia. If the serum tryptase is elevated during the event but no allergic agent can be identified, a further serum tryptase should be taken several weeks later to exclude a persistent elevation due to mastocytosis.

An evaluation of the relative efficacy of an open airway, an oxygen reservoir and continuous positive airway pressure 5 cmH2O on the non-ventilated lung.

The aim of this study, during one-lung ventilation, was to evaluate if oxygenation could be improved by use of a simple oxygen reservoir or application of 5 cmH2O continuous positive airway pressure (CPAP) to the non-ventilated lung compared with an open airway. Twenty-three patients with lung malignancy, undergoing thoracotomy requiring at least 60 minutes of one-lung ventilation before lung lobe excision, were studied. After routine induction and establishment of one-lung ventilation, the three treatments were applied in turn to the same patient in a sequence selected randomly. The first treatment was repeated as a fourth treatment and these results of the repeated treatment averaged to minimize the effect of slow changes. Arterial oxygenation was measured by an arterial blood gas 15 minutes after the application of each treatment. Twenty patients completed the study. Mean PaO2 (in mmHg) was 210.3 (SD 105.5) in the "OPEN" treatment, 186.0 (SD 109.2) in the "RESERVOIR" treatment, and 240.5 (SD 116.0) in the "CPAP" treatment. This overall difference was not quite significant (P = 0.058, paired ANOVA), but comparison of the pairs showed that there was a significant better oxygenation only with the CPAP compared to the reservoir treatments (t = 2.52, P = 0.021). While the effect on the surgical field was not apparent in most patients, in one patient surgery was impeded during CPAP. Our results show that the use of a reservoir does not give oxygenation better than an open tube, and is less effective than the use of CPAP 5 cmH2O on the non-ventilated lung during one-lung ventilation.

The frequency of pleural effusions after Bellovac drainage following coronary bypass grafting.

BACKGROUND: A common postoperative complication after CABG with internal mammary artery (IMA) harvest is the evolution of a pleural effusion. Our aim was to see if the intra-operative insertion of a Bellovac drain to the pleural cavity, with drainage continuing for 4-days post operation, eliminates the complication of pleural effusion. METHODS: Using our computerised audit database, 500 consecutive patients were identified who had undergone CABG including at least one internal mammary graft by a single consultant at Blackpool Victoria Hospital. All these patients received Bellovac drainage for 4 days on the side of the harvested IMA. The chest X-ray reports were retrospectively collected from the hospital computer databases. The 4-day post-operative, and the 6-week post-operative films were found. In the cases where no consultant radiologist report was found J.D. reviewed the film, and any abnormalities were also reviewed by R.W.J.M. RESULTS: Out of 500 radiographs, six patients (1.2%) died, 25 patients had no traceable record of a chest X-ray, 434 patients had an entirely normal chest X-ray and 461 patients had no effusion at 6 weeks. Six patients had a small effusion at 6 weeks, two had a moderate effusion successfully treated conservatively, and no patients had a pleural effusion that required drainage. CONCLUSION: In patients undergoing coronary arterial bypass grafting with internal mammary artery harvest, the intra-operative insertion of a Bellovac drain on the side of the harvested IMA reduces the risk of postoperative pleural effusions

Metabolic and immunologic consequences of laparoscopy with helium or carbon dioxide insufflation: a randomized clinical study.

BACKGROUND: Previous studies using animal models have demonstrated that carbon dioxide (CO2) pneumoperitoneum during laparoscopy is associated with adverse physiological, metabolic, immunological and oncological effects, and many of these problems can be avoided by the use of helium insufflation. The present study was performed in patients to compare the effect of helium and CO2 insufflation on intraperitoneal markers of immunological and metabolic function. METHODS: Eighteen patients undergoing elective upper gastrointestinal laparoscopic surgery were randomized to have insufflation achieved by using either helium (n = 8) or CO2 (n = 10) gas. Intraperitoneal pH was monitored continuously during surgery, and peritoneal macrophage function was determined by harvesting peritoneal macrophages at 5 min and 30 min after commencing laparoscopy, and then assessing their ability to produce tumour necrosis factor-alpha (TNF-alpha), and their phagocytic function. RESULTS: Carbon dioxide laparoscopy was associated with a lower intraperitoneal pH at the commencement of laparoscopy, although this difference disappeared as surgery progressed. The production of TNF-alpha was better preserved by CO2 laparoscopy, but the insufflation gas used did not affect macrophage phagocytosis. Patients undergoing helium laparoscopy required less postoperative analgesia. CONCLUSION: The choice of insufflation gas can affect intraperitoneal macrophage function in the clinical setting, and possibly acid-base balance. The present study suggested no immunological advantages for the clinical use of helium as an insufflation gas. The outcomes of the present study, however, are different to those obtained from previous laboratory studies and further research is needed to confirm this outcome.

Monoclonal light chain--mesangial cell interactions: early signaling events and subsequent pathologic effects.

Glomerulopathic monoclonal light chains (G-LC) interact with mesangial cells (MC), resulting in alterations of mesangial homeostasis. Early signaling events control mitogenic activities and cytokine production, which in turn participate in the subsequent pathologic events. Mesangial homeostasis is affected in two very different ways, depending on whether the G-LC is from a patient with light chain deposition disease (LCDD) or light chain-related amyloidosis (AL-Am). In contrast, tubulopathic (T)-LC chains from patients with myeloma cast nephropathy do not significantly interact with MC and result in no alterations in mesangial homeostasis. Therefore, understanding early events in the monoclonal LC-MC interactions is fundamental. MC in culture were exposed to LC obtained and purified from the urine of patients with plasma cell dyscrasias and biopsy-proven renal disease, including LCDD, AL-Am, and myeloma cast nephropathy. Incubation of MC with G-LC, but not T-LC, resulted in cytoskeletal and cell shape changes, activation of platelet-derived growth factor-beta (PDGF-beta) and its corresponding receptor, cytoplasmic to nuclear migration of c-fos and NF-kappa beta signals, and production of monocyte chemoattractant protein-1 (MCP-1), as well as increased expression of Ki-67, a proliferation marker. Although NF-kappa beta activation was directly related to MCP-1 production, c-fos activation regulated proliferative signals and cytoskeletal changes in MC. Amyloidogenic LC were avidly internalized by the MC, whereas LCDD-LC effector targets were located at the MC surface. These cellular events are likely initiated as a result of interactions of the G-LC with yet-uncharacterized MC surface receptors. Dissecting the events taking place when G-LC interact with MC may define potential important targets for selective therapeutic manipulation to ameliorate or prevent the glomerular injury that ensues.

Are nasal spectacles adequate for supplementary oxygen in patients after anaesthesia?

Two methods of oxygen delivery were compared when used postoperatively after a general anaesthetic had been administered. There were 255 patients randomly allocated to receive oxygen via nasal spectacles or a Hudson face mask in the initial postoperative period. Oxygen saturation was monitored using pulse oximetry. Seven percent of patients who received the Hudson mask and 14% of patients who received nasal spectacles desaturated below 94% (P = 0.10). Age, weight or American Society of Anesthesiologists (ASA) status did not predict oxygen desaturation; however, desaturation occurred more frequently in male patients with nasal spectacles undergoing abdominal surgery. If male patients who had abdominal surgery with muscle relaxants are excluded from the nasal spectacle group, the desaturation incidences for spectacles and masks are similar (10% versus 7%, P = 0.38). Using nasal spectacles for all postoperative oxygen therapy in selected patients is therefore feasible and could provide substantial cost-saving.

Glomerulopathic light chain-mesangial cell interactions modulate in vitro extracellular matrix remodeling and reproduce mesangiopathic findings documented in vivo.

Glomerulopathic light chains (LCs) are associated with two distinct mesangiopathies: AL (light-chain-related) amyloidosis and light-chain deposition disease (LCDD) with immunomorphologic features that are well documented in the literature. Even though both conditions are caused by monoclonal LCs, these entities differ dramatically in their morphologic expressions. In AL amyloidosis the mesangial matrix is replaced by amyloid fibrils, while in LCDD the matrix increases as a consequence of deposition of excess extracellular matrix (ECM). The immunomorphologic mesangial alterations observed in biopsy material are closely reproduced in vitro when mesangial cells grown on an artificial matrix are incubated with monoclonal light chains obtained from the urine of patients with either condition. This article summarizes previously reported data, reports new findings, and focuses on integrating all the available information on the subject. When mesangial cells are incubated with LCDD-LCs, production of ECM proteins (collagen IV, laminin, fibronectin, and tenascin) is increased, with maximum effect at 72 hours post LC treatment. A concomitant decrease in collagenase IV activity further accentuates the accumulation of mesangial matrix. These effects are mediated through transforming growth factor-beta (TGF-beta) activation. In contrast, when mesangial cells are incubated with Am-LCs, a decrease in ECM protein production and a stimulatory effect on collagenase IV is observed, which results in matrix degradation and facilitates amyloid deposition. The decreased TGF-beta documented in the literature in this setting precludes adequate matrix repair. These findings substantiate the morphologic alterations observed in renal biopsy specimens and in the in vitro model. Using this in vitro model, it is then possible to delineate the LC interactions with putative receptors at the mesangial cell surface that regulate mesangial cell pathobiologic responses and mesangial matrix homeostasis.

Radiation therapy among atomic bomb survivors, Hiroshima and Nagasaki.

As a follow-up to the two previous surveys of radiation therapy among the atomic bomb survivors, a large-scale survey was performed to document (1) the number of radiation therapy treatments received by the atomic bomb survivors and (2) the types of radiation treatments conducted in Hiroshima and Nagasaki. The previous two surveys covered the radiation treatments among the Radiation Effects Research Foundation Adult Health Study (AHS) population, which is composed of 20,000 persons. In the present survey, the population was expanded to include the Life Span Study (LSS), including 93,611 atomic bomb survivors and 26,517 Hiroshima and Nagasaki citizens who were not in the cities at the times of the bombings. The LSS population includes the AHS population. The survey was conducted from 1981 to 1984. The survey teams reviewed all the medical records for radiation treatments of 24,266 patients at 11 large hospitals in Hiroshima and Nagasaki. Among them, the medical records for radiation treatments of 1556 LSS members were reviewed in detail. By analyzing the data obtained in the present and previous surveys, the number of patients receiving radiation therapy was estimated to be 4501 (3.7%) in the LSS population and 1026 (5.1%) in the AHS population between 1945-1980. During 1945-1965, 98% of radiation treatments used medium-voltage X rays, and 66% of the treatments were for benign diseases. During 1966-1980, 94% of the radiation treatments were for malignant neoplasms. During this period, 60Co gamma-ray exposure apparatus and high-energy electron accelerators were the prevalent mode of treatment in Hiroshima and in Nagasaki, respectively. The mean frequency of radiation therapy among the LSS population was estimated to have been 158 courses/year during 1945-1965 and 110 courses/year during 1966-1980. The present survey revealed that 377 AHS members received radiation therapy. The number was approximately twice the total number of cases found in the previous two surveys. Thus the data on radiation therapy in the AHS members have been updated well by this survey, and will provide information for more precise dose-response analyses of radiation effects in the AHS population. The information extracted from the medical records of the hospitals consisted of hospital names, treatment periods, body sites treated, diagnoses, treatment doses, radiation sources, the field sizes of the exposures and the data for identification of the patients. These data will be essential in estimating the organ doses from scattered radiation and in evaluating the effects of therapeutic radiation.