Transcatheter Aortic Valve-in-Valve Replacement for Degenerated Stentless Bioprosthetic Aortic Valves: Results of a Multicenter Retrospective Analysis.

OBJECTIVES: The purpose of this study was to evaluate the safety and efficacy of valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR) for stentless bioprosthetic aortic valves (SBAVs) and to identify predictors of adverse events. BACKGROUND: ViV TAVR in SBAVs is associated with unique technical challenges and risks. METHODS: Clinical records and computer tomographic scans were retrospectively reviewed for procedural complications, predictors of coronary obstruction, mortality, and echocardiographic results. RESULTS: Among 66 SBAV patients undergoing ViV TAVR, mortality was 2 of 66 patients (3.0%) at 30 days and 5 of 52 patients (9.6%) at 1 year. At 1 year, left ventricular end-systolic dimension was decreased versus baseline (median [interquartile range (IQR)]: 3.0 [2.6 to 3.6] cm vs. 3.7 [3.2 to 4.4] cm; p < 0.001). Coronary occlusion in 6 of 66 procedures (9.1%) resulted in myocardial infarction in 2 of 66 procedures (3.0%). Predictors of coronary occlusion included subcoronary implant technique compared with full root replacement (6 of 31, 19.4% vs. 0 of 28, 0%; p = 0.01), short simulated radial valve-to-coronary distance (median [IQR]: 3.4 [0.0 to 4.6] mm vs. 4.6 [3.2 to 6.2] mm; p = 0.016), and low coronary height (7.8 [5.8 to 10.0] mm vs. 11.6 [8.7 to 13.9] mm; p = 0.003). Coronary arteries originated <10 mm above the valve leaflets in 34 of 97 unobstructed coronary arteries (35.1%). CONCLUSIONS: TAVR in SBAVs is frequently associated with high-risk coronary anatomy but can be performed with a low risk of death and myocardial infarction, resulting in favorable ventricular remodeling. A subcoronary surgical approach is associated with an increased risk of coronary obstruction.

Is Dysphagia After Cardiac Operations a "Preexisting Condition"?

BACKGROUND: Controversy exists about the incidence of dysphagia after cardiac operations, and very little is known about the baseline risk in this patient population. This study evaluated the incidence of dysphagia both preoperatively and postoperatively in patients undergoing cardiac operations. METHODS: Patients undergoing cardiac operations were screened for dysphagia preoperatively using a 90-mL water swallow challenge protocol, a mini cognitive/speech screen, and a modified oral mechanism screen. The tests were repeated after extubation once the patient was alert and oriented. Patient characteristics were analyzed in conjunction with the results of the swallow screens to identify risk factors for dysphagia. RESULTS: Of 176 patients tested, 15 (8.5%) failed the swallow screen preoperatively. Age, gender, and comorbidities were compared. Patients who failed the swallow study preoperatively were slightly older (76.1 vs 73.3 years, p = 0.047) and had a higher incidence of chronic renal failure (13.3% v. 0.6%, p = 0.017), but gender and other comorbidities were not significantly different. Postoperatively, 38 patients failed the swallow screen (21.6%). Those who failed the postoperative screen were also older (75.6 vs 72.9 years, p = 0.012), but other factors (including chronic renal failure) were not significantly different. All of the patients who failed the swallow screen preoperatively also failed postoperatively. CONCLUSIONS: Unrecognized dysphagia in patients who need cardiac operations is a common problem and accounts for a substantial portion of that seen postoperatively. Older patients are at increased risk of dysphagia, but gender and medical comorbidities are not useful predictors of this risk.

Impaired event memory and recollection in a case of developmental amnesia.

A current debate in the literature is whether all declarative memories and associated memory processes rely on the same neural substrate. Here, we show that H.C., a developmental amnesic person with selective bilateral hippocampal volume loss, has a mild deficit in personal episodic memory, and a more pronounced deficit in public event memory; semantic memory for personal and general knowledge was unimpaired. This was accompanied by a subtle difference in impairment between recollection and familiarity on lab-based tests of recognition memory. Strikingly, H.C.'s recognition did not benefit from a levels-of-processing manipulation. Thus, not all types of declarative memory and related processes can exist independently of the hippocampus even if it is damaged early in life.

Brain stem death testing after thiopental use:A survey of UK neuro critical care practice.

A postal survey was conducted to determine how thiopental is used in UK neurosurgery critical care units. Thirty units were contacted and 26 replied. Thiopental is used in 23 units. The majority (60%) of these units govern the use of thiopental with protocols or guidelines and 74% use cerebral monitoring to guide dosage. When patients have had thiopental, 20 units delay brain stem testing, two will not perform tests and one unit incorporates cerebral angiography into their protocol. Twelve units use serum thiopental assays in their brain stem testing procedures, but there is wide variation in the interpretation of the results. We found inconsistency and confusion surrounding brain stem testing in this patient group, raising the possibility of misdiagnosis of brain stem death.

Sexual dimorphism in trauma? A retrospective evaluation of outcome.

PURPOSE: Multiple studies have demonstrated a heightened immune response in female animals subjected to trauma-hemorrhage models and have implied a subsequent survival advantage. PROCEDURES: A retrospective review of outcome in 15,170 trauma admissions over a 5-year-period (1993-1997) at a level 1-trauma center was performed. A comparison of outcome by gender, age, injury severity score (ISS), mechanism of injury, location of injury (AIS), and length of hospitalization (intensive care unit and total hospitalization) was performed. FINDINGS: There were 12,456 male and 2714 female patients included in the study. Overall survival rates (male = 90.2%, female = 90.8%) and survival of serious (ISS > or = 15) trauma (male = 63.5%, female = 60.5%) were not statistically different. Logistic regression analysis identified age, mechanism and ISS as factors associated with survival. CONCLUSION: Retrospective evaluation of our trauma population failed to show a difference in outcome between male and female trauma patients. Age, mechanism and severity of injury-but not gender-were identified as factors influencing survival.

Impact of the number of negative nodes on disease-free survival in colorectal cancer patients.

PURPOSE: Between 1995 and 1999, we observed an increasing number of nodes being recovered from colorectal specimens. Patients with colorectal cancer were studied to determine whether increasing the number of negative nodes recovered would better stage the patient and more accurately predict disease-free survival. METHODS: All patients undergoing colorectal resection with curative intent between 1995 and 1999 at a tertiary referral hospital were retrospectively reviewed. Tumor stage, grade, number of nodes recovered, and the association of these factors with disease-free survival was analyzed. RESULTS: Three hundred forty-five patients with M0 disease undergoing surgical resection of carcinoma of the colon or rectum were studied. There was no statistically significant difference in tumor stage or grade during the study period. A statistically significant increase in the mean number of nodes recovered was observed during the study period. Node-positive patients did substantially worse than node-negative individuals. When compared with a national cancer registry (OncoPool), we observed a significantly greater number of nodes sampled in our study population and a statistically significant improved disease-free survival between our node-negative patients and that of the national cancer registry population. CONCLUSION: The extent of the pathologic assessment of the nodal status of colorectal cancer patients as determined by the number of nodes examined affects disease-free survival. The need for quality control for uniform pathologic assessments is critical.

Evaluation of the Pneupac Ventipac portable ventilator in critically ill patients.

We assessed adequacy of ventilation in 20 critically ill patients with multiple organ failure using a Pneupac Ventipac portable ventilator and the effects on patients' haemodynamic stability. Baseline data were recorded over 15 min for a range of respiratory, haemodynamic and oxygen transport variables during ventilation with a standard intensive care ventilator (Engström Erica). Patients were then ventilated for 40 min using the portable ventilator. Finally, they were ventilated for a further 40 min using the standard intensive care ventilator. Heart rate, arterial and pulmonary artery pressures were recorded at 5-min intervals throughout the study period. Cardiac index and other haemodynamic data derived from a pulmonary artery catheter were recorded at 20-min intervals. Blood gas analysis was performed and oxygen transport data (oxygen delivery, oxygen consumption and physiological shunt) were calculated at the end of each of the three periods of ventilation. In general, no significant adverse effects of ventilation using the portable ventilator were observed for any of the variables studied. Arterial PO(2) increased significantly during ventilation with the portable ventilator, reflecting the use of a higher inspired oxygen fraction during this part of the study. Oxygen consumption decreased significantly in one patient during ventilation by the portable ventilator although none of the other variables measured in this patient was altered. We conclude that ventilation of critically ill patients using the Pneupac Ventipac portable ventilator was safe, satisfactory and associated with minimal adverse effects on respiratory, haemodynamic and oxygen transport variables.

Safety and efficacy of radiofrequency thermal ablation in advanced liver tumors.

HYPOTHESIS: Radiofrequency thermal ablation (RFA) can be performed safely and effectively to control local disease in patients with advanced, unresectable liver tumors. DESIGN, SETTING, AND PATIENTS: Prospective study of 76 patients with unresectable liver tumors who underwent RFA at a private tertiary referral hospital. INTERVENTIONS: Ninety-nine RFA operations were performed to ablate 328 tumors. MAIN OUTCOME MEASURES: Complications and local recurrence. RESULTS: There was 1 death (1%), major complications occurred in 7 operations (7%), and minor complications occurred in 10 operations (10%). Local recurrence was identified in 30 tumors (9%) at a mean follow-up of 15 months. Size (P<.001), vascular invasion (P<.001), and total volume ablated (P<.001) were associated with recurrence but the number of tumors was not (P =.39). CONCLUSION: Radiofrequency thermal ablation provides local control of advanced liver tumors with low recurrence and acceptable morbidity.

Coronary artery bypass performed without the use of cardiopulmonary bypass is associated with reduced cerebral microemboli and improved clinical results.

STUDY OBJECTIVES: Strokes and neurocognitive dysfunction have been correlated with cerebral microemboli produced during cardiopulmonary bypass (CPB). The purpose of this study was to determine whether, and to what extent, off-pump coronary artery bypass (OPCAB) reduces the occurrence of cerebral microemboli compared with traditional coronary artery bypass grafting (CABG) with CPB and to compare clinical results. DESIGN AND PATIENTS: A retrospective review of 137 patients undergoing elective CABG was performed, 70 of whom underwent traditional CABG and 67 of whom underwent OPCAB. Using transcranial Doppler ultrasonography, 40 patients (20 CABG, 20 OPCAB) were continuously monitored intraoperatively for the occurrence and pattern of cerebral microemboli. SETTING: Private, university-affiliated tertiary care hospitals. RESULTS: There was no statistical difference in the age, sex, or underlying comorbidities between those patients undergoing CABG and OPCAB. CABG patients did have a slightly lower preoperative ejection fraction (50.9% vs 55.5%, p = 0.03). Despite these similar preoperative characteristics, the OPCAB group experienced significant reductions in cerebral microemboli (27 vs 1,766, p = 0.003), transfusion requirements (29.9% vs 47.1%, p = 0.04), intubation time (3.3 vs 9.5 h, p < 0.001), ICU length of stay (1.5 vs 2.8 days, p = 0.02), and overall hospitalization (4.9 vs 6.6 days, p = 0.01) without an increase in mortality. Fewer strokes and deaths were observed in the OPCAB group, but these trends failed to reach statistical significance. CONCLUSIONS: In similar patient populations, OPCAB was associated with significantly fewer cerebral microemboli and improved clinical results without an increase in mortality. We believe that these early results support OPCAB as a viable and potentially safer alternative to traditional CABG.

Coronary artery bypass grafting performed with or without a bypass pump: early results.

INTRODUCTION: Traditionally, heart bypass surgery has required stopping of the heart and the use of cardiopulmonary bypass. Numerous complications have been associated with exposure to this extracorporeal circuit. Newer techniques of local cardiac wall stabilization now enable this operation to be performed safely "Off Pump". The early clinical results of Off Pump Coronary Artery Bypass (OPCAB) will be compared to a similar group of traditional Coronary Artery Bypass Grafting (CABG) patients. METHODS: A retrospective review of 137 consecutive patients undergoing elective coronary artery bypass grafting was performed, 68 of who underwent traditional CABG and 69 of who underwent OPCAB. Inclusion criteria consisted of first time cardiac surgical procedures with an ejection fraction > or = 20%, without significant renal failure (creatinine < 2.0). RESULTS: There was no statistical difference in the age, sex, cardiac function or underlying co-morbidities between those undergoing CABG and OPCAB. CABG patients had slightly more vessels bypassed than those in the OPCAB group (3.0 vs 2.6, p = 0.010). Despite similar preoperative characteristics, the OPCAB group experienced a reduction in morbidity without an increase in mortality. CONCLUSION: In similar patient populations, OPCAB was associated with significantly reduced transfusion requirements, intubation time, ICU and overall hospital lengths of stay, with no increase in mortality. Further investigation is warranted to ascertain the role of the OPCAB in the general cardiac surgical community.

Fifteen years' experience with an antirefluxing biliary drainage valve.

PURPOSE: The aim of this study was to examine the efficacy of the antirefluxing, mucosal-flap valve (AMFV) for biliary drainage relative to technical feasibility, surgical complications, and incidence of ascending cholangitis (AC). METHODS: Twenty-seven infants requiring biliary tract reconstruction underwent valve construction. Twenty biliary atresia (BA) patients received the Kasai procedure, and 7 choledochal cyst (CC) infants had cystectomy and hepatoenterostomy. A retrospective review of all patients was performed including radiographic evaluation of the current valve function in 10 patients. RESULTS: Construction was successful in all cases, and no morbidity was incurred by incorporation of the valve. Of 7 CC patients, there have been no known episodes of AC with mean follow-up of 4.4+/-4.2 years. Of 20 BA patients, there have been 5 deaths (25%), 7 liver transplants (35%), 2 (10%) lost to follow-up, and 6 (30%) survivors. Nine BA patients (45%) have had AC, with patients in all 4 outcome categories represented. Ten patients (5 CC and 5 BA) have been evaluated with barium small bowel radiographs, with no reflux to the liver hilum in all cases. CONCLUSIONS: The AMFV has caused no morbidity and continues to prevent reflux to the liver hilum. Despite functioning as designed, it does not appear to influence the occurrence of AC. Because CC patients had no AC, we feel that infection is related to the underlying atresia rather than to reflux.

Comparison of lactate and bicarbonate buffered haemofiltration fluids: use in critically ill patients.

OBJECTIVE: To compare acid-base balance, lactate concentration, and haemodynamic and O2 transport variables during haemofiltration with replacement fluid containing 44.5 mmol/l Na+ lactate or 40 mmol/l Na+ HCO3- and 3 mmol/l lactic acid. DESIGN: A prospective, randomized trial. SETTING: A multidisciplinary, adult intensive care unit in a university hospital. PATIENTS: Forty acidotic patients who required haemofiltration, were dependent on mechanical ventilation, and had PA catheters in situ. INTERVENTIONS: During haemofiltration patients received lactate or bicarbonate replacement fluid at a mean rate of 1.7 l/h (SD 0.3). Arterial blood gases, plasma lactate, and haemodynamic and O2 transport variables were measured before and after 12 and 24 h haemofiltration. Ultrafiltrate was collected for lactate estimation. MEASUREMENTS AND MAIN RESULTS: As means (SD). The net gain of lactate was 63 mmol/h (12 mmol) with Na+ lactate and 0 mmol/h (0.3 mmol) with Na+ HCO3-. There was a significant increase in pH and [lactate] in both groups, but [lactate] was higher in patients receiving lactate. Twenty-one patients survived to ICU discharge, these patients were significantly less acidotic after filtration (lactate group: 0 h: pH 7.23 (0.09), [lactate] 2.4 mmol/l (1.7); 12 h: pH 7.34 (0.09), [lactate] 4.7 mmol/l (2.4); 24 h: pH 7.36 (0.07), [lactate] 4.7 mmol (2.7). HCO3 group: 0 h: pH 7.23 (0.09), [lactate] 2.3 (1.3); 12 h: pH 7.32 (0.06), [lactate] 2.9 mmol/l (1.8); 24 h: pH 7.35 (0.08), [lactate] 2.8 mmol/l (2.0). Base deficit: survivors: 0 h: 9 mmol/l (4); 12 h: 2 mmol/l (3). Non-survivors: 0 h: 10 mmol/l (3); 12 h: 6 mmol/l (3)). Haemodynamic and O2 transport variables were not significantly affected by treatment group or outcome. CONCLUSIONS: The degree of correction of acidosis during the first 24 h of haemofiltration was determined by patients outcome but was not affected by the substitution of bicarbonate- for lactate-containing replacement fluids.

The prognostic value of serial measurements of serum albumin concentration in patients admitted to an intensive care unit.

The prognostic value of serial measurements of serum albumin concentration during the first 72 h after admission to a general adult intensive care unit was retrospectively reviewed in 348 consecutive critically ill patients over a one year period. The accuracy of the admission APACHE II (Acute Physiology And Chronic Health Evaluation) score in correctly predicting patient outcome was compared with the serum albumin concentration measured at different times after intensive care unit admission. Multiple logistical regression analyses were performed to evaluate whether combining APACHE II and serum albumin into a unified risk index improved prognostic accuracy. Serum albumin concentration on admission was lower in non-survivors than in survivors and decreased more rapidly in non-survivors (p < 0.001). The admission serum albumin concentration was found to be an insensitive prognostic indicator. However, serum albumin measured after 24 h was as accurate as the admission APACHE II score in correctly classifying patients according to outcome. There was a good correlation between the admission APACHE II score and serum albumin measured after 24 h but not between the admission APACHE II and the admission serum albumin. Combining the APACHE II score and serial albumin concentrations into a unified risk of death equation did not improve the accuracy of outcome prediction.

Analgesia for venous cannulation: a comparison of EMLA (5 minutes application), lignocaine, ethyl chloride, and nothing.

Three commonly available local anaesthetics were compared, in a controlled trial, for use before venous cannulation. The pain of application of the local anaesthetic, the pain of cannulation, and the rate of successful cannulations were compared. The value of EMLA cream applied for 5 min was questioned. Venous cannulation with a 20G venflon was found to be significantly more painful than the application of any of the local anaesthetics (P < 0.01). Lignocaine 1%, injected subcutaneously, and ethyl chloride spray significantly reduced the pain of venous cannulation (P < 0.01). The use of lignocaine did not result in significantly more failed cannulations than the control group. It was concluded that local anaesthesia should be used before venous cannulation, even for 20G cannulae.

Pharmacokinetics of propofol during and after long-term continuous infusion for maintenance of sedation in ICU patients.

The pharmacokinetics of propofol administered as long term infusions were determined in 12 intensive care unit patients (two female; mean age 58 yr, mean weight 66.9 kg) requiring sedation during mechanical ventilation. Patients were recruited after having been administered propofol for 24 h. Blood samples for analysis of propofol were taken during the infusion (mean duration 85.6 h; mean rate 2.58 mg kg-1 h-1) and for up to about 42 h after its termination. The median propofol total body clearance, derived from the apparent steady state propofol blood concentrations during infusion, was 2.11 litre min-1. One patient died during the infusion, from multi-organ failure secondary to a pre-existing septicaemia, and in one other patient no sampling was possible during the first 30 min after infusion; full elimination data were obtained for 10 patients. After termination of the infusion, propofol blood concentrations declined rapidly, with an overall mean decrease of 50% over the first 10 min; thereafter the decline was more gradual. The elimination profile was triphasic in seven patients and biphasic in three patients. Mean half-lives for the three phases were 1.81 (n = 10) min, 70.9 (n = 7) min and 1411 (n = 11) min. There was no apparent trend in the terminal phase half-life with the duration of sampling after infusion.