Determinants of outcome after carotid endarterectomy

Background: The efficacy of carotid endarterectomy for selected patients has been evaluated with randomized controlled clinical trials. The generalizability of these studies to average surgical practice remains an important public health concern. Objective: The objective of the study was to determine the predictors of outcome after carotid endarterectomy on a regional basis. Patients and Methods: The study was designed as a retrospective cohort study and included all consecutive patients presented for carotid endarterectomy at the 8 University of Toronto–affiliated hospitals in the period from January 1, 1994, to December 31, 1996. The main outcome measure was 30-day postoperative stroke or death rate. Results: During the study interval, 1280 primary carotid endarterectomies were performed. The overall combined stroke and death rate was 6.3% for all patients who underwent endarterectomy (4.0% for patients who were asymptomatic). The significant predictors of poor outcome were the following: presenting symptoms (odds ratio, 1.74; 95% confidence interval [CI], 0.96, 3.12), low surgeon volume (<6 cases per year; odds ratio, 3.98; 95% CI, 1.65, 9.58), and left-sided surgery (odds ratio, 1.72; 95% CI, 1.07, 2.76). Conclusion: These data suggest that adoption of the recommendations of the symptomatic carotid endarterectomy trials is appropriate. However, endarterectomy for asymptomatic lesions remains of uncertain benefit on a regional basis and must be individualized to the experience of the specific surgeon. The surgeon volume/outcome relationship that is identified in this study suggests a need for a minimum volume threshold for this procedure. (J Vasc Surg 1998;28:1051-8.)     

Early vasopressin improves short-term survival after pulmonary contusion

Arginine vasopressin (AVP) is a promising treatment for several types of irreversible shock, but its therapeutic potential has not been examined after severe chest trauma. Two series of experiments were performed to fill this gap. METHODS: Series 1: anesthetized, mechanically-ventilated pigs (n = 20, 29 +/- 1 kg) received a blast to the chest, followed by a "controlled" arterial hemorrhage to a mean arterial pressure (MAP) <30 mm Hg. At 20 minutes, a 10 mL/kg normal saline (NS) bolus was followed by either 0.1 U/kg AVP bolus or NS, in randomized, blinded fashion. From 30-300 minutes, either AVP (0.4 U/kg/hr plus NS) or NS alone was infused as needed to MAP>70 mm Hg. Series 2: Swine (n = 15) received the chest injury followed by partial left hepatectomy to produce "uncontrolled" hemorrhage. Resuscitation was the same as in series 1. RESULTS: The blast created bilateral parenchymal contusions (R > L), hemo/pneumothorax and progressive cardiopulmonary distress. In Series 1, there were 3/20 deaths before randomization, 0/8 deaths after resuscitation with AVP versus 4/9 deaths with NS (p = 0.029). In surviving animals, with AVP versus NS, fluid requirements and peak airway pressures were lower while P/F was higher (all p < 0.05). In Series 2, with uncontrolled hemorrhage, there were 5/15 deaths before randomization. Upon resuscitation with AVP versus NS, survival time and blood loss were both improved, but the differences did not reach statistical significance. CONCLUSIONS: After severe chest trauma with controlled hemorrhage, early AVP decreased mortality, reduced fluid requirements and improved pulmonary function. With uncontrolled hemorrhage, early AVP did not increase the risk for bleeding.     

Determinants of outcome after heterotopic heart transplantation.

BACKGROUND: Donor availability is currently the major factor limiting the use of heart transplantation as a treatment for severe heart failure. Heterotopic heart transplantation may address this issue by allowing the use of smaller donor organs, which otherwise may not be used. METHODS: We analyzed the outcome of 42 consecutive, adult heterotopic transplantations performed between 1993 and 1999 at our center and compared them with the 303 consecutive orthotopic transplants performed in adult patients during the same period. METHODS: Univariate analysis showed a relative risk for death of 1.8 at 1 year after transplantation for the heterotopic group compared with the orthotopic transplantation group (p = 0.04). Multiple regression analysis using a proportional hazards model showed that donor-recipient size-mismatch, i.e., donor body surface area < or =75% of recipient body surface area (p = 0.0001), donor age (p = 0.0001), and use of a female donor (p = 0.04) were significant risk factors but heterotopic transplantation per se was not. A Kaplan-Meier survival analysis of heterotopic vs orthotopic transplantation showed that 30-day survival was 76% vs 87%. By 1 year, this was 59% vs 74%. At 3 years, the comparison was 56% vs 69%. Repeating this analysis after sub-dividing the heterotopic group into those size-matched vs size-mismatched, the 1-year survival was 81% vs 45%, respectively (p = 0.02). CONCLUSIONS: Heterotopic transplantation using a size-matched graft resulted in similar survival to that seen after orthotopic transplantation during the same period. Heterotopic transplantation with an undersized graft resulted in significantly decreased survival.     

Novel resuscitation strategy for pulmonary contusion after severe chest trauma

BACKGROUND: Adenosine A2a receptor stimulation can increase coronary perfusion and also reduce leukocyte-mediated inflammatory responses in some conditions. Hextend is a novel colloid solution that may have antioxidant properties. All these actions might be beneficial after severe chest trauma, but have never been investigated. To fill these gaps, this study evaluated the therapeutic potential of a novel adenosine A2a agonist during fluid resuscitation from severe chest trauma with either standard-of-care crystalloid or Hextend. METHODS: Anesthetized, ventilated swine received unilateral, blunt trauma to the right chest via captive bolt gun, followed by a 10- to 12-mL/kg arterial hemorrhage. After 25 minutes of shock, ATL-146e was started (10 ng/kg/min intravenously for 180 minutes). After an additional 5 minutes, the minimum amount of either colloid (Hextend, 5% hetastarch in lactate-buffered, balanced electrolyte solution) or crystalloid (lactated Ringer's [LR] solution) was administered to maintain mean arterial pressure > 70 mm Hg and heart rate < 100 beats/min and to correct lactate for 180 minutes postinjury. Cardiopulmonary function was monitored and serial bronchoalveolar lavage samples were analyzed for protein, leukocyte infiltration, and expression of cyclooxygenase (COX)-1 and COX-2 isozymes as markers of the inflammatory cascade. RESULTS: Fluid requirements were reduced by half with Hextend compared with LR (p < 0.05). ATL-146e in either Hextend or LR transiently increased cardiac output, cardiac contractility, and systemic oxygen delivery (all p < 0.05). Pao(2)/Fio(2) ratio was 50 to 100 higher and bronchoalveolar lavage leukocytes were reduced by half with Hextend versus LR (both p < 0.05), but there was no added effect of ATL-146e. COX-1 expression was induced in macrophages (Mphis), whereas COX-2 was induced in neutrophils. Neither Hextend nor ATL-146e reduced COX expression. CONCLUSION: Hextend reduced the volume for initial resuscitation, which may offer logistical advantages in prehospital field conditions or whenever there is limited medical resources or prolonged transport times; ATL-146e improved early cardiac performance without causing hypotension or bradycardia; when administered 25 to 30 minutes after injury, neither Hextend nor ATL-146e altered inflammatory changes in pulmonary Mphis or infiltrating PMNs; and further studies are needed to determine whether these short-term benefits correlate with long-term outcome.     

Determinants of patient satisfaction with outcome after shoulder arthroplasty

The purpose of this investigation was to identify the determinants of patient satisfaction with outcome after hemiarthroplasty and total shoulder arthroplasty. Seventy patients who underwent shoulder arthroplasty were studied to determine predictors of patient satisfaction. Patient satisfaction was graded on an ordinal scale from 1 to 10. There was a significant association between patient satisfaction and age (P = .010) and between patient satisfaction and worker's compensation status (P = .018). There was no significant decrease in patient satisfaction for patients with rotator cuff tears. Patient satisfaction was significantly associated with all pain and function variables at follow-up (P < .05). The American Shoulder and Elbow Surgeons score was significantly correlated with patient satisfaction (P = 0.680, P < .05). Independent predictors of satisfaction included pain with activities of daily living, painless use of the arm above the shoulder, and difficulty with toileting (R(2) = 0.555). Subjective variables associated with pain were independent predictors of patient satisfaction. Thus, in assessing patient satisfaction after shoulder arthroplasty, we emphasize the importance of patient-derived subjective assessment of symptoms and function.     

Variables affecting outcome in blunt chest trauma: flail chest vs. pulmonary contusion

We reviewed 144 consecutive patients with flail chest and/or pulmonary contusion between 1979 and 1984. The purpose was to analyze the factors adversely affecting morbidity and mortality. There were 97 males and 47 females, with an average age of 40 years +/- 18 S.D. (range, 2-83). Seventy-five per cent of the injuries were caused by motor vehicle accidents, with the remainder due to falls (17%), cardiopulmonary resuscitation (4%), altercations (2%), or falling objects (2%). The Injury Severity Score (ISS) averaged 32 +/- 14 S.D. in all survivors versus 60 +/- 14 S.D. in those who died. Eighty-three patients (58%) required mechanical ventilation. Thirty-six patients died (25%). Isolated pulmonary contusion or flail chest had a mortality of 16% each. However, the mortality more than doubled when there was a combined pulmonary contusion and flail chest (42%). More than half of all deaths were directly attributed to central nervous system injuries with another third due to massive hemorrhage. Factors that were associated with a higher morbidity and mortality included severe associated thoracic injuries, a high ISS, the presence of shock, falls from heights, and the combination of pulmonary contusion and flail chest.     

Flail chest and pulmonary contusion

Flail chest is most often accompanied by a significant underlying pulmonary parenchymal injury and can be a life-threatening thoracic injury. Its management is often complicated by the other injuries it is frequently associated with. Similarly, mortality and morbidity are dictated most often by the associated injuries and findings. Its treatment is complex and should first be one of pain management, judicious fluid resuscitation, and excellent pulmonary toilet. In those patients requiring mechanical ventilatory support, or who require ipsilateral thoracocotomy, rib stabilization may be considered depending on a host of potentially conflicting indications and contraindications. At the end of this section are listed the current major recommendations and their levels of evidence.     

Determinants of patient satisfaction with outcome after rotator cuff surgery

BACKGROUND: The outcome after rotator cuff surgery has been reported frequently with use of condition-specific measures, but patient satisfaction has not been well studied. The purpose of this study was to identify the determinants of patient satisfaction with the outcome after rotator cuff surgery. METHODS: A cohort of 311 patients undergoing rotator cuff surgery was studied prospectively. Two hundred and fifty-four patients had subjective follow-up for a minimum of one year, and fifty-seven patients had subjective and objective follow-up for a minimum of one year. Diagnoses included tendinitis or impingement (eighty patients), a partial-thickness rotator cuff tear (fifty-five patients), and a full-thickness rotator cuff tear (176 patients). The dependent variable was patient satisfaction with the outcome, graded ordinally on a scale of 1 to 10. Independent variables included demographic, surgical, objective follow-up, and subjective follow-up parameters. Univariate and multivariate analyses were performed to identify the determinants of satisfaction. RESULTS: Univariate analysis of demographic variables demonstrated no significant differences (p > 0.05) with respect to patient satisfaction. Analysis of the surgical variables showed significantly decreased satisfaction (p < 0.05) for patients who had debridement for a massive, irreparable cuff tear; those who had subscapularis tears; and those with larger supraspinatus and infraspinatus tears. Analysis of the objective variables at follow-up demonstrated significantly decreased satisfaction (p < 0.05) for patients with diminished and weakened forward elevation, impingement signs, and acromioclavicular joint pain and tenderness. Univariate analysis of subjective variables at follow-up showed significantly decreased satisfaction (p < 0.001) for patients with pain, functional difficulty, and work disability. Multivariate analysis demonstrated significantly decreased satisfaction associated with pain (p < 0.001) and dysfunction (p < 0.05). A significant relationship (p < 0.05) was detected between satisfaction and a willingness to recommend the surgery to another. A significant relationship (p < 0.05) was also found between satisfaction and the American Shoulder and Elbow Surgeons score. CONCLUSIONS: Subjective variables of symptoms and function have the most robust associations with patient satisfaction following rotator cuff surgery. Thus, in assessing the outcome of rotator cuff surgery from the perspective of patient satisfaction with outcome, we emphasize the importance of patient-derived subjective assessment of symptoms and function.     

Determinants of late outcome after minimally invasive direct coronary artery bypass

AIM: Minimally invasive direct coronary artery bypass (MIDCAB) is a reliable method to revascularize the left anterior descending (LAD) coronary artery. However, a more consistent body of knowledge is needed to assess factors influencing long-term outcome. With this study, we retrospectively investigated the long-term determinants of survival and freedom from cardiac morbidity and revascularization in patients who underwent MIDCAB. METHODS: From 1997 to 2005, 109 patients underwent MIDCAB. Seventy-five (68.8%) presented isolated LAD disease and 34 (31.2%) multivessel disease. The first 57 patients (53.2%) in the series underwent early postoperative angiographic reinvestigation. All 109 patients were subsequently followed-up at our outpatient clinic. Follow-up (mean 50.7 months, range 3-93) was completed in 100% of cases. RESULTS: No in-hospital deaths occurred; 2 patients (1.8%) experienced perioperative myocardial infarction. At early postoperative angiographic reinvestigation, the anastomotic perfect patency rate was 54/57 (94.7%); survival was 100% and 95.8% at 1 and 5 years, respectively. Overall freedom from repeated revascularization was 95.3% and 88.3% at 1 and 5 years respectively; freedom from LAD revascularization was 95.3% and 91.6% at 1 and 5 years, respectively; cardiac event-free survival was 95.3% and 80.8% at 1 and 5 years respectively. At multivariable analysis (Cox regression), women were found to have a higher risk of repeated LAD revascularization (hazard ratio [HR] 30.24; P<0.001); female sex and left ventricular dysfunction were the only predictors affecting long-term cardiac outcome (hazard ratio 29.35; P<0.001 and 5.1; P<0.001), respectively. CONCLUSIONS: A key factor in the long-term success of MIDCAB seems to be appropriate patient selection. Special attention should be reserved for female patients, as they appear to have a worse cardiac outcome and a higher probability of repeated revascularization on LAD. MIDCAB may represent a viable option for treating multivessel disease when complete revascularization is unfeasible or a hybrid procedure is envisaged.     

Determinants of patient satisfaction with outcome after anterior cruciate ligament reconstruction

BACKGROUND: The purpose of this study was to identify the determinants of patient satisfaction with the outcome after reconstruction of the anterior cruciate ligament. METHODS: A cohort of 201 patients undergoing primary reconstruction of the anterior cruciate ligament was studied prospectively. All patients were followed for a minimum of two years (mean, 35.9 months). The dependent variable was patient satisfaction with the outcome, graded ordinally on a scale of 1 to 10. Nonparametric univariate analysis and multivariable modeling were performed to identify determinants of satisfaction. RESULTS: The demographic variables were not found to have a significant association (p > 0.05) with patient satisfaction. The variables at surgery demonstrated a significant association (p < 0.05) with patient satisfaction only with respect to the status of the lateral meniscus, the presence of osteophytes, and concurrent plica excision. The objective variables at follow-up revealed that patients were significantly less satisfied (p < 0.05) if they had a flexion contracture, increased laxity of the involved leg on the manual maximum test as measured on a KT-1000 device, an abnormal result on the pivot-shift examination, effusion, or tenderness at the medial joint line or patella. With regard to the subjective symptoms at follow-up, patients were found to be significantly (p < 0.05) less satisfied with the outcome if they had symptoms of pain, swelling, partial giving-way, full giving-way, locking, noise, stiffness, or a limp. Analysis of the subjective function at follow-up demonstrated that patients were significantly less satisfied (p < 0.05) with the outcome if they had a lower level of activity, sports activity, strenuous work, activities of daily living, overall knee function, sports participation, or symptom-free activity; if they were unemployed; or if they had difficulty with walking, squatting, ascending or descending stairs, running, jumping, cutting, or twisting. Patient satisfaction was significantly associated (p < 0.05) with the Lysholm knee score, overall International Knee Documentation Committee (IKDC) knee score, IKDC subjective subscore, IKDC symptoms subscore, and IKDC range-of-motion subscore. The seven independent multivariate determinants (adjusted R (2) = 0.83, p < 0.001) of patient satisfaction included the Lysholm score, overall subjective knee function, IKDC range-of-motion subscale, patellar tenderness, full giving-way, flexion contracture, and swelling. CONCLUSIONS: Univariate and multivariate determinants of patient satisfaction with the outcome after reconstruction of the anterior cruciate ligament were established. Although some specific surgical and objective variables were important, subjective variables of symptoms and function had the most robust associations with patient satisfaction. In assessing the outcome of reconstruction from the perspective of patient satisfaction with the outcome, we should emphasize patient-derived subjective assessment of symptoms and function, particularly those involving issues of stiffness, giving-way, swelling, and patellofemoral symptoms.     

Crystalloid resuscitation of patients with pulmonary contusion

One hundred nine patients with the diagnosis of pulmonary contusion were studied retrospectively. Thirteen deaths were respiratory related (12 percent of patients). All of the patients were quickly resuscitated with crystalloid solutions as necessary to restore perfusion to normal. Twenty-eight of the most severely injured patients, all of whom were intubated and ventilated and in whom serial PaO2 and total protein determinations were available, were examined for the relationship between crystalloid induced hemodilution as measured by the plasma colloid oncotic pressure and oxygenation as measured by the PaO2/FiO2 ratio. When survivors and nonsurvivors were analyzed by group, both individually and collectively, no correlation was found between oxygenation and oncotic pressure. Survivors and nonsurvivors exhibited similar post-traumatic courses in the PaO2/FiO2 ratios with differences not becoming significant until the eleventh day after injury. We conclude that contusion is not a progressive lesion unless pneumonia supervenes and that pulmonary dysfunction after contusion is unrelated to hemodilution.