Association Between Three-Dimensional Left Ventricular Outflow Tract Area and Gradients After Myectomy in Hypertrophic Obstructive Cardiomyopathy.

OBJECTIVE: Determine whether the intraoperative three-dimensional left ventricular outflow tract cross-sectional area may be inversely correlated with pressure gradients as a determinant of surgical success after septal myectomy in hypertrophic cardiomyopathy patients. DESIGN: Perioperative data were obtained by retrospective review. SETTING: Toronto General Hospital, University of Toronto, Toronto, Canada, a tertiary hospital. PARTICIPANTS: The study comprised 67 patients with hypertrophic obstructive cardiomyopathy. INTERVENTIONS: Transthoracic and intraoperative transesophageal echocardiographic assessment of pressure gradients. Transesophageal measurement of the three-dimensional left ventricular outflow tract cross-sectional area. MEASUREMENTS AND MAIN RESULTS: The smallest left ventricular outflow tract area increased on average 1.883 cm2 (98.3%) after septal myectomy. There was a significant correlation between the increase in the area and the transesophageal pressure gradients (r = -0.32; p = 0.01) after myectomy, but none with postoperative transthoracic gradients at rest (r = -0.10; p = 0.42). Postoperative transesophageal and transthoracic gradients were significantly correlated (r = 0.26; p = 0.04). The best risk factors to predict high residual gradients were preoperative transesophageal gradient >97 mmHg, postoperative transesophageal area <3.16 cm2, and moderate or more residual transesophageal mitral regurgitation (specificity 89%, 81%, and 78%, respectively). CONCLUSIONS: Three-dimensional left ventricular outflow tract area measurements with transesophageal echocardiography after myectomy correlated fairly well with postoperative transesophageal pressure gradients. Patients with residual transthoracic elevated gradients after surgery at follow-up had a smaller transesophageal area and higher transesophageal pressure gradients immediately after the procedure. However, transesophageal pressure gradients after myectomy correlated poorly with follow-up transthoracic gradients at rest.

Hypertrophic cardiomyopathy: current understanding and treatment objectives.

The understanding of hypertrophic cardiomyopathy (HCM) has changed dramatically over the last few decades, and it is now understood to be caused by a mutation in one of several cardiac sarcomeric genes. Due to complications such as outflow tract obstruction, diastolic dysfunction, arrhythmias, stroke, infective endocarditis and sudden cardiac death, appropriate and early identification of these patients is imperative. This review attempts to summarise the current state of knowledge on HCM, and provide insight of the appropriate investigations needed in patients with HCM. It also outlines treatment strategies for these patients. Much remains unknown about this complex and intriguing disease, and continued research in identifying the genetic basis of HCM, along with the assessment of therapeutic strategies, will help to optimise patient care.

Short-term low-dose propofol anaesthesia associated with severe metabolic acidosis.

Propofol-induced metabolic acidosis is well recognised in the paediatric literature, but the existence of such a syndrome in adults remains contentious. In most reported cases, metabolic acidosis complicated prolonged administration of propofol in critically ill patients. We present a case of severe non-fatal reversible metabolic acidosis, without ventilatory depression or hypoxia, related to short-term propofol infusion in an adult during and after coronary artery bypass grafting. We suggest that lactic acidosis occurred in a genetically susceptible patient with an abnormality of mitochondrial function. This report discusses an unusual adverse effect of propofol anaesthesia and sedation and highlights the need for further investigation to define propofol toxicity.

A phase II dose-response study of hemoglobin raffimer (Hemolink) in elective coronary artery bypass surgery.

BACKGROUND: We performed this study to determine the dose-response of hemoglobin raffimer administered in conjunction with intraoperative autologous donation in patients undergoing coronary artery bypass grafting surgery. A secondary objective was to evaluate hemoglobin raffimer for reducing the incidence of allogeneic red blood cell transfusions. METHODS: This was a phase II, single-blind, multicenter, placebo-controlled, open-label study. Patients undergoing coronary artery bypass grafting with cardiopulmonary bypass and intraoperative autologous donation were randomized to receive a single dose of hemoglobin raffimer or control (10% pentastarch). Patients were sequentially enrolled in a dose block of 250, 500, 750, and 1000 mL. RESULTS: Sixty patients received hemoglobin raffimer (n = 30) or control (n = 30). Hemoglobin raffimer was well tolerated. Most (98%) adverse events were mild or moderate in severity. There was an expected dose-dependent increase in the incidence of blood pressure increases and jaundice in hemoglobin raffimer-treated patients. In a dose-pooled analysis of hemoglobin raffimer versus control, increased blood pressure (43% vs 17%), nausea (37% vs 33%), and atrial fibrillation (37% vs 17%) were the most frequently reported adverse events. All serious adverse events were considered unrelated or unlikely to be related to study drug. No hemoglobin raffimer-treated patient required an intraoperative allogeneic red blood cell transfusion, compared with 5 (17%) pentastarch-treated patients (P =.052). This advantage of hemoglobin raffimer was maintained at 24 hours after surgery (7% vs 37%; P =.010) and up to 5 days after surgery (10% vs 47%; P =.0034). CONCLUSIONS: Hemoglobin raffimer was not associated with any serious adverse events in patients undergoing primary coronary artery bypass grafting with cardiopulmonary bypass and intraoperative autologous donation in a dose-response study up to 1000 mL. Hemoglobin raffimer was effective in facilitating decreased exposure or avoidance of allogeneic red blood cell transfusions when used in conjunction with intraoperative autologous donation.

Valve surgery in octogenarians.

OBJECTIVE: To review the outcomes of octogenarians undergoing valve operations. PATIENTS AND METHODS: One hundred and twenty-five consecutive patients aged 80 years and over received valve operations between 1990 and 1996 at the Toronto General Hospital, Toronto, Ontario. All hospital survivors were prospectively followed for a mean of 36.6 months (range 0.1 to 89.9). RESULTS: One hundred and two patients received aortic valve operations, 18 patients received mitral procedures and five patients underwent double valve operations. Significant aortic stenosis was present in 95 of 102 patients (93%) receiving isolated aortic valve surgery, and mitral regurgitation was present in 16 of 18 patients (89%) undergoing mitral valve operations. Overall in-hospital mortality was 6.4% (n=8) and the perioperative infarction rate was 1.6% (n=2). In-hospital mortality was higher for mitral valve patients at 17% (n=3) than for aortic valve patients at 4% (n=4) (P=0.06). For the group overall, the six-year actuarial survival rate was 71.6+/-6%. The actuarial freedom from valve-related death was 97.1+/-2% at three years. Concomitant coronary artery disease was not significantly associated with perioperative mortality. Survivors had significantly improved New York Heart Association functional class status. CONCLUSION: In carefully selected patients aged 80 years and over, aortic valve surgery carries a low perioperative mortality with good intermediate term survival and benefits. Octogenarians undergoing mitral valve procedures experience higher perioperative mortality. Although the number of participants was small for this study, it does appear that coexistent coronary artery disease should not be the sole reason for denial of surgery because it has less of an impact on short and intermediate term survival than other factors.

Permanent cardiac pacing after a cardiac operation: predicting the use of permanent pacemakers.

BACKGROUND: The need for permanent cardiac pacing after cardiac operations is infrequent but associated with increased morbidity and resource utilization. We identified patient risk factors for pacemaker insertion to enable development of a predictive model. METHODS: Data were collected prospectively for 10,421 consecutive patients who had cardiac operations between January 1990 and December 1995. Two hundred fifty-five patients (2.4%) were identified as having received a permanent pacemaker during the same hospitalization. Logistic regression analysis was performed to determine the independent, multivariate predictors of permanent pacing. The predictive accuracy and precision of the logistic regression model was evaluated in the 1996 database of 2,236 consecutive patients by the calculation of Brier scores. RESULTS: Eight independent predictors of permanent pacemaker requirement were identified. The factor-adjusted odds ratios (OR) with 95% confidence interval (CI) associated with each predictor are as follows: (1) valve replacement surgery (aortic: OR 5.8, CI 3.9-8.7; mitral: OR 4.9, CI 3.1-7.8; tricuspid: OR 8.0, CI 5.5-11.9; double: OR 8.9, CI 5.5-14.6; and triple: OR 7.5, CI 2.9-19.3); (2) repeat operation: OR 2.4, CI 1.8-3.3; (3) age 75 years or older: OR 3.0, CI 2.0-4.4; (4) ablative arrhythmia operation: OR 4.2, CI 1.9-9.5; (5) mitral valve annular reconstruction: OR 2.4, CI 1.4-4.2; (6) use of cold blood cardioplegia: OR 2.0, CI 1.2-3.6; (7) preoperative renal failure: OR 1.6, CI 1.0-2.6; and (8) active endocarditis: OR 1.7, CI 0.9-3.0. A model for postoperative permanent pacemaker requirement using the eight predictors was formulated and tested (Brier score = 0.017+/-0.003; Z = 0.18). CONCLUSIONS: The proposed predictive model correlated highly with actual pacemaker use, which suggests that the requirement for pacing results from either operative trauma or increased ischemic burden. Preoperative identification of patients at increased risk of conduction disturbances may allow for earlier detection and improved treatment. Patients requiring postoperative pacing had increased morbidity and length of stay.

Reoperation for recurrent aortic coarctation.

BACKGROUND: Recurrence of stenosis is a complication of coarctation repair associated with major long-term morbidity. Persistent or exercise-provoked hypertension may indicate recurrent coarctation. Patients failing or not amenable to balloon dilation should be managed surgically. METHODS: A retrospective chart review was performed. RESULTS: Forty-three patients were identified as having undergone repeat surgical intervention for recurrent aortic coarctation between the years 1976 and 1993 at The Hospital for Sick Children in Toronto. Seventy percent of the children had other congenital cardiac anomalies. Eighty-six percent of patients initially treated by subclavian flap aortoplasty or end-to-end anastomosis were managed at reoperation by patch aortoplasty, and 26% of patients also required augmentation of the transverse arch (under hypothermic circulatory arrest) for accompanying hypoplasia. Three patients underwent a second reoperation; all were treated at this reoperation with tube graft interposition. CONCLUSIONS: No ischemic spinal injury occurred in patients managed with either simple proximal aortic cross-clamping or cardiopulmonary bypass. No patient treated with transverse arch augmentation required further surgical intervention. Mortality at reoperation was 7% (3 patients), similar to that of first-time coarctation repair. At follow-up (mean duration, 4.5 years), 57% of patients are normotensive, with no measurable arm-leg gradient.

Atypical presentation of spontaneous pneumomediastinum.

Spontaneous pneumomediastinum is a rare clinical entity; when diagnosis is certain, no treatment is required and symptoms rarely recur. The clinical presentation is usually diagnostic; however, atypical symptoms may mandate further investigation before diagnosis can be established. We describe 2 patients with spontaneous pneumomediastinum who presented with dominant esophageal symptoms (odynophagia and dysphagia) suggestive of esophageal perforation. Investigation and management are discussed.

Massive perirenal and intra-abdominal bleeding after shock-wave lithotripsy: case report.

Complications of extracorporeal shock-wave lithotripsy are rare, with an incidence of symptomatic perinephric hematoma ranging from 0.2% to 0.66%. A 59-year-old man had massive symptomatic retroperitoneal and intra-abdominal bleeding 24 hours after lithotripsy. The hemorrhage was managed successfully by conservative measures, which consisted of packed red blood cells and fresh frozen plasma. The literature on the bleeding complications of lithotripsy is reviewed and the risk factors are identified.

Infective endocarditis in patients who had replacement of the aortic root.

In 12 patients who had had composite replacement of the aortic valve and ascending aorta, infective endocarditis developed 2 months to 17 years after operation. Six patients had mechanical valves and 6 had biological ones (four homograft and two porcine valves). All patients needed operation because of shock, heart failure, persistent sepsis in spite of adequate antibiotic therapy, or the development of a paravalvular false aneurysm. The predominant microorganism was Staphylococcus. All 6 patients who had mechanical valves were found to have an abscess in the junction between the aortic annulus and the prosthesis; in patients who had biological valves the infection was limited to the leaflets in 3 (one homograft and two porcine valves) and leaflets and annulus abscess in 3 (three homograft valves). Operation consisted of radical resection of tissues suspected of being infected and reconstruction of the left ventricular outflow tract and of the surrounding structures with glutaraldehyde-fixed bovine pericardium. The aortic valve and ascending aorta were replaced with a new valved conduit. An aortic homograft was used in only 1 patient. There was only one operative death due to right ventricular infarction but most patients experienced serious postoperative complications. Operative survivors were followed up from 3 to 156 months (mean, 42 months). One patient died 35 months postoperatively due to bleeding complications of anticoagulation; 1 patient suffered a cardiac arrest at home 2 months after operation, sustained permanent cerebral damage, and died 4 months later. The remaining patients are asymptomatic from the cardiovascular viewpoint.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful treatment of massive pulmonary embolism after coronary artery bypass grafting due to heparin-induced thrombocytopenia.

Massive pulmonary embolism is a rare complication in patients undergoing coronary artery bypass grafting. Frequently patients have had exposure to heparin before the operation. In this article we report a patient who 6 days after a cardiac operation suffered a massive pulmonary embolism. The patient was later discovered to have heparin-associated thrombocytopenia with serum heparin antibody. We recommend patients receiving heparin have frequent platelet counts and those with induced thrombocytopenia undergo sensitivity testing.

Preoperative cardiac evaluation of the patient with vascular disease.

OBJECTIVE: To review the literature and evaluate the investigation of cardiac risk factors, by tests and intraoperative predictors, that will identify patients at high risk for vascular surgery. DATA SOURCES: An English-language literature review of Index Medicus articles from 1961 to 1992. STUDY SELECTION: Published articles that addressed preoperative risk factors, diagnostic tests and intraoperative predictors were selected by multiauthor consensus. DATA EXTRACTION: Independent extraction by multiple authors was utilized to abstract and assess the quality of data from selected references, with consensus determining inclusion or exclusion. DATA SYNTHESIS: From evaluation of published data, a number of factors were considered to put a patient scheduled to undergo vascular surgery at higher risk: symptomatic coronary artery disease; clinical evidence of coronary artery disease, congestive heart failure, aortic stenosis and recent myocardial infarction; laboratory findings of significant disease with cardiomegaly or significant dysrhythmias; and no symptoms but two or more risk factors. CONCLUSIONS: The authors propose an algorithm for the investigation of patients and stratification of risk to be considered in weighing the dangers versus the benefits of vascular surgery.

Sudden rupture of an indirect inguinal hernial sac with extravasation in two patients on continuous ambulatory peritoneal dialysis.

Continuous ambulatory peritoneal dialysis (CAPD) is commonly used to treat patients suffering from end-stage renal failure. This method can be used on a long-term basis and in the short term for patients awaiting renal transplantation. Inguinal hernias are a potential source of morbidity for these patients. Therefore, when patients with inguinal hernias require long-term peritoneal dialysis, the hernia should be repaired if the patient's medical status will allow it. The authors report on two patients maintained on CAPD who experienced rapid enlargement and perforation of a previously undiagnosed asymptomatic inguinal hernia. The hernia was repaired successfully, without complication, in both cases.

Pulmonary Complications in Obesity Surgery.

Massively obese patients undergoing abdominal surgery frequently develop pulmonary complications. The basis of this predilection, syndromes and suggestions to reduce risk are discussed.

Management of papillary carcinoma arising in thyroglossal-duct anlage.

Cysts of the thyroglossal duct are common congenital abnormalities. They present as asymptomatic midline cervical swellings. The risk of malignant change is low; only 103 cases have been reported in the world literature, 85% of which were papillary adenocarcinomas. The appropriate treatment for this condition remains controversial. The authors describe three patients who had papillary carcinoma contained within a thyroglossal-duct rest. All were treated by cyst resection and thyroid suppression, but without thyroidectomy and radioactive thyroid ablation. Postoperatively, all patients remained disease free, with no recurrence at follow-up ranging from 10 to 29 years. Isolated papillary carcinomas arising from primitive thyroid remnants, associated with a palpably normal thyroid gland at surgery and a negative thyroid scan, can be treated adequately by excising the thyroglossal mass.

A Jejuno-ileal Bypass Patient Presenting with Recurrent Renal Stones due to Primary Hyperparathyroidism.

In the past, jejuno-ileal (JI) bypass operations were performed for the treatment of massive intractable obesity. This procedure is known to be complicated by numerous malabsorptive syndromes, occasionally resulting in electrolyte abnormalities and oxalate renal calculi. Recurring renal stones and oxalate nephropathy are cause to reverse the JI bypass. However, investigation of recurring renal stones should be done to exclude causes that are not secondary to the bypass procedure itself. We present a patient 13 years post JI bypass with recurring renal calculi due to primary hyperparathyroidism.

Diet Coke or Not?

Many obese patients are attempting to diet. Furthermore, many gastric restrictive procedures permit the ready flow of liquids, and the individual may want to be assured that the liquid is in the "non-calorie" form. Many obese patients have diabetes, and an incorrect or misrepresented beverage can result in elevated plasma glucose with a disruption in glycemic control. The studies below have been extended for orange-flavored carbonated beverages (Orange Crush, Fanta Orange, etc.) with the same findings-no color change with the diet drink and immediate brown color change with the regular drink on the Diastix.