Racial Differences in Blood Pressure and Autonomic Recovery Following Acute Supramaximal Exercise in Women

Despite the growing popularity of high-intensity anaerobic exercise, little is known about the acute effects of this form of exercise on cardiovascular hemodynamics or autonomic modulation, which might provide insight into the individual assessment of responses to training load. The purpose of this study was to compare blood pressure and autonomic recovery following repeated bouts of acute supramaximal exercise in Black and White women. A convenience sample of twelve White and eight Black young, healthy women were recruited for this study and completed two consecutive bouts of supramaximal exercise on the cycle ergometer with 30 min of recovery in between. Brachial and central aortic blood pressures were assessed by tonometry (SphygmoCor Xcel) at rest and 15-min and 30-min following each exercise bout. Central aortic blood pressure was estimated using brachial pressure waveforms and customized software. Autonomic modulation was measured in a subset of ten participants by heart-rate variability and baroreflex sensitivity. Brachial mean arterial pressure and diastolic blood pressure were significantly higher in Blacks compared to Whites across time (race effect, p = 0.043 and p = 0.049, respectively). Very-low-frequency and low-frequency bands of heart rate variability, which are associated with sympathovagal balance and vasomotor tone, were 22.5% and 24.9% lower, respectively, in Blacks compared to Whites (race effect, p = 0.045 and p = 0.006, respectively). In conclusion, the preliminary findings of racial differences in blood pressure and autonomic recovery following supramaximal exercise warrant further investigations of tailored exercise prescriptions for Blacks and Whites.

Identifying the value of RVEF for the prediction of major cardiovascular outcomes: a study of 7,131 patients undergoing cardiovascular magnetic resonance imaging

Background

Right ventricular (RV) function remains poorly recognized for its value in predicting cardiovascular events at a population level. Cardiovascular Magnetic Resonance (CMR) imaging is the gold standard for RV assessment.

Purpose

To define the independent prognostic value of RVEF for the prediction of major adverse cardiovascular events (MACE) as primary outcome in patients with known or suspected cardiovascular disease.

Methods

Data was obtained from the Cardiovascular Imaging Registry of Calgary (CIROC). Patients underwent standardized CMR imaging protocols and analysis. Clinical events were identified from administrative data.

Results

7,131 patients were included. 870 primary outcome events occurred over 2.5 years follow-up. RVEF provided equivalent predictive utility versus LVEF (Table 1). There was an increase in events with worsening severity of RVEF (Figure 1), with a significant “threshold-effect” at an RVEF of 40%.

Conclusions

RVEF is a strong and independent predictor of MACE at a population level.

Figure 1

Funding Acknowledgement

Type of funding source: None

Development and validation of a risk model for the prediction of cardiovascular hospital admission using CMR-based phenotype in patients with known or suspected cardiovascular disease

Background

Cardiovascular diseases remain the leading cause of morbidity worldwide and impose the highest economic burden among noncommunicable diseases. Much of these costs are related to hospitalizations for adverse cardiovascular events, which may be reduced by targeted management of high-risk patients. Cardiac markers derived from CMR imaging have been shown to be strong independent predictors of prognosis within specific cohorts. However, its capacity to broadly contribute to risk models aimed at predicting incident cardiac hospitalization has not been demonstrated.

Purpose

Using a large clinical outcomes registry of patients clinically referred for CMR, develop and validate a nomogram for prediction of cardiovascular hospital admission.

Methods

A total of 7127 consecutive patients were prospectively recruited between 02/2015 and 07/2019. All patients completed standardized health questionnaires and CMR imaging protocols. A nomogram was developed for prediction of cardiovascular hospitalization, inclusive of admission for heart failure, MI, cardiac arrest, heart transplant, LVAD implantation, or stroke. The risk model was derived from 80% (n=5702) of the cohort using Cox modelling that included CMR, medication, laboratory, and patient-reported health variables. Model validation was assessed by discrimination and calibration procedures applied to the remaining 20% of patients (n=1425). A minimum follow-up of six months was mandated.

Results

The derivation cohort was comprised of 38% females with a median age of 56 (IQR 44–65) years. During a median follow-up of 934 days, 514 (9.0%) events occurred. The validation cohort was similarly comprised of 37% females with a median age of 57 (IQR 44–66) years. During a median follow-up of 970 days, 142 (10.0%) events occurred. Numerous CMR parameters were significantly different between those experiencing versus not experiencing the primary composite outcome, including: LVEF (44% vs 59%, p<0.0001), RVEF (52% vs 55%, p<0.0001), LV mass (65g/m2 vs 56g/m2, p<0.0001), and LA volume (43mL/m2 vs 34mL/m2, p<0.0001). These and other CMR-derived characteristics were independently predictive of the composite outcome by univariate modelling (Figure 1A). An eight-variable nomogram (Figure 1B) was developed using a stepwise multivariate model that exhibited high discrimination in both the derivation and validation cohorts (C-index 0.81 and 0.83, respectively). Continuous model calibration curves indicated satisfactory external performance. The model was able to discriminate risk of hospitalization at 1-year with a dynamic range of 20–99%.

Conclusion

Using data available at time of CMR imaging, we derived and validated a Cox-based nomogram that offers robust prediction of future cardiovascular admissions. This tool may provide value for the identification of patients who may benefit from targeted surveillance and management strategies, and may offer a foundation for improved patient-specific cost modelling.

Figure 1

Funding Acknowledgement

Type of funding source: None

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

4941Machine learning based automated diagnosis of ischemic vs non-ischemic dilated cardiomyopathy using 3D myocardial deformation analysis

Background

Late Gadolinium Enhancement (LGE) imaging is a reference standard technique for the differentiation of ischemic cardiomyopathy (ICM) from non-ischemic dilated cardiomyopathy (NIDCM) in patients with heart failure and reduced ejection fraction (HFrEF). 3D myocardial deformation analysis (3D-MDA) offers highly reproducible phenotypic assessments of regional architecture and function that may provide value for artificial-intelligence-assisted cardiomyopathy diagnosis without need for LGE imaging.

Purpose

In this study, we trained and validated a machine-learning-based model to enable automated diagnosis of ischemic versus non-ischemic dilated cardiomyopathy exclusively using regional patterns of deformation among patients otherwise matched by age, sex and global contractile dysfunction.

Methods

100 ICM and 100 NIDCM patients matched for age, sex, and LVEF underwent standard cine SSFP and LGE imaging. Patient diagnoses were established using a combination of clinical and LGE-based criteria. 3D-MDA was performed using validated software (GIUSEPPE) to compute regional 3D strain measures at each cardiac phase in both conventional and principal strain directions. Principal Component Analysis (PCA) was performed on the composite 3D-MDA dataset. The first 20 components were chosen, accounting for approximately 65% of the population variance. Subsequently, a support-vector-machine-based algorithm was used with 10-fold cross-validation to discriminate ICM from NIDCM.

Results

Patients were 63±10 years (ICM: 63±10 years, NIDCM: 63±10 years, p=0.955), 74% male (ICM: 74%, NIDCM: 74%, p=1.000), and had a mean LVEF of 27±8% (ICM: 27±7%, NIDCM: 28±7%, p=0.688). Global time to peak strain was significantly shorter in ICM patients relative to NIDCM patients across all surfaces and in all directions (p<0.05). The highest single-variable Area Under the Curve (AUC) achieved for the classification of ICM versus NIDCM from global data was for minimum principal strain (ICM: 43.7±7.8, NIDCM: 48.3±7.5, p<0.001, AUC: 0.682) (Figure 1). However, a multi-feature machine-learning-based model exposed to all available regional 3D deformation data achieved an AUC of 0.903 (sensitivity 87.7%, specificity 75.5%).

Conclusions

Machine learning-based analyses of3D regionaldeformation patterns allows for robust discrimination of ICM versus NIDCM. Further expansion of the presented findings is planned on a wider, multi-centre cohort.

Acknowledgement/Funding

Dr. White was supported by an award from Heart and Stroke Foundation of Alberta. This study was funded in part by Calgary Health Trust.

Machine-learning to characterise neonatal functional connectivity in the preterm brain

Brain development is adversely affected by preterm birth. Magnetic resonance image analysis has revealed a complex fusion of structural alterations across all tissue compartments that are apparent by term-equivalent age, persistent into adolescence and adulthood, and associated with wide-ranging neurodevelopment disorders. Although functional MRI has revealed the relatively advanced organisational state of the neonatal brain, the full extent and nature of functional disruptions following preterm birth remain unclear.

In this study, we apply machine-learning methods to compare whole-brain functional connectivity in preterm infants at term-equivalent age and healthy term-born neonates in order to test the hypothesis that preterm birth results in specific alterations to functional connectivity by term-equivalent age.

Functional connectivity networks were estimated in 105 preterm infants and 26 term controls using group-independent component analysis and a graphical lasso model. A random forest–based feature selection method was used to identify discriminative edges within each network and a nonlinear support vector machine was used to classify subjects based on functional connectivity alone.

We achieved 80% cross-validated classification accuracy informed by a small set of discriminative edges. These edges connected a number of functional nodes in subcortical and cortical grey matter, and most were stronger in term neonates compared to those born preterm. Half of the discriminative edges connected one or more nodes within the basal ganglia.

These results demonstrate that functional connectivity in the preterm brain is significantly altered by term-equivalent age, confirming previous reports of altered connectivity between subcortical structures and higher-level association cortex following preterm birth.

•

Robust classification of preterm and term-born neonates using functional connectivity patterns.

•

Discriminative pattern of alterations in basal ganglia and frontal connections.

•

Reflects system-wide disruption of subcortical–cortical connections following preterm birth.

The effects of hemorrhagic parenchymal infarction on the establishment of sensori-motor structural and functional connectivity in early infancy

INTRODUCTION

The objective of the study was to characterize alterations of structural and functional connectivity within the developing sensori-motor system in infants with focal perinatal brain injury and at high risk of cerebral palsy.

METHODS

Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) data were used to study the developing functional and structural connectivity framework in six infants born prematurely at term equivalent age. This was first characterised in three infants without focal pathology, which was then compared to that derived from three infants with unilateral haemorrhagic parenchymal infarction and a subsequent focal periventricular white matter lesion who developed later haemiparesis.

RESULTS

Functional responses to passive hand movement were in the contralateral perirolandic cortex, regardless of focal pathology. In infants with unilateral periventricular injury, afferent thalamo-cortical tracts appeared to have developed compensatory trajectories which circumvented areas of damage. In contrast, efferent corticospinal tracts showed marked asymmetry at term equivalent age following focal brain injury. Sensori-motor network analysis suggested that inter-hemispheric functional connectivity is largely preserved despite pathology and that impairment may be associated with adverse neurodevelopmental outcome.

CONCLUSION

Following focal perinatal brain injury, altered structural and functional connectivity is already present and can be characterized with MRI at term equivalent age. The results of this small case series suggest that these techniques may provide valuable new information about prognosis and the pathophysiology underlying cerebral palsy.

Pretreatment with n-6 PUFA protects against subsequent high fat diet induced atherosclerosis--potential role of oxidative stress-induced antioxidant defense

OBJECTIVES

Recent evidence suggests that oxidative stress can promote antioxidant defense and thus be athero-protective. n-6 polyunsaturated fatty acids (n-6 PUFA) are more prone to oxidation, compared to monounsaturated fatty acids (MUFA) and yet have proven anti-atherosclerotic effects. In this study, we tested whether early exposure to a diet rich in n-6 PUFA, compared to a MUFA rich diet would reduce lesion burden, even with subsequent exposure to a high fat, high cholesterol diet (HF). Further, we tested to determine whether oxidative mechanisms are involved in such protection.

METHODS AND RESULTS

Twenty four, 4 week old, male, LDL receptor knockout (LDL-R(-/-)) mice were divided into two groups and fed either a n-6 PUFA rich or a MUFA rich diet for a period of 12 weeks. At this point, 4 mice from each group were euthanized and the remaining 8 mice from each group were fed a HF diet for four weeks. Atherosclerotic lesions, plasma lipids, autoantibodies to lipid peroxide modified proteins, isoprostanes and aortic catalase levels were measured. The n-6 PUFA diet reduced aortic lesions and plasma lipids compared to the MUFA diet and this reduction in lesions continued even after the mice were switched over to the HF diet, despite the fact that the plasma lipids were similar in both groups after the HF diet. n-6 PUFA fed mice had highest plasma isoprostane levels, indicating oxidative stress, but also had higher levels of aortic catalase. On the other hand, MUFA fed mice had comparatively lower levels of isoprostanes and their aortic catalase levels remained low. Finally, aortic lesions were negatively correlated with isoprostanes and catalase.

CONCLUSION

An initial exposure to a n-6 PUFA rich diet compared to a MUFA rich diet reduces atherosclerotic lesions and this protection probably involves oxidative stress induced by PUFA.

Somatosensory cortical activation identified by functional MRI in preterm and term infants

Functional MRI (fMRI) has not previously been used systematically to investigate brain function in preterm infants. We here describe statistically robust and reproducible fMRI results in this challenging subject group using a programmable somatosensory stimulus synchronized with MR image acquisition which induced well-localized positive blood oxygen level dependent (BOLD) responses contralateral to the side of the stimulation in: 11 preterm infants (median post menstrual age 33 weeks and 4 days, range 29+1 to 35+3); 6 control infants born at term gestational age; and 18 infants born preterm (median gestational age at birth 30 weeks and 5 days, range 25+4 to 36+0) but studied at term corrected gestational age. Bilateral signals were identified in 8 of the ex-preterm infants at term age. Anatomical confirmation of appropriate activations was provided with diffusion tensor imaging (DTI) based tractography which identified connecting pathways from the regions of activation through the ipsilateral corticospinal tracts and posterior limb of the internal capsule. These results demonstrate that it is possible to reliably identify positive BOLD signals in the infant brain and that fMRI techniques can also be applied in the study of preterm infants.

Clinicopathologic profile of 470 giant cell tumors of bone from a cancer hospital in western India

Over 20 years, 470 cases of giant cell tumor of bone diagnosed at a tertiary cancer hospital were analyzed. Male predominance (57%), predilection for bones around the knee joint (42%), and occurence in the 21- to 30-year-old age group (49.1%) with 6% being in the immature skeleton are well known facts. Accurate diagnosis was possible in 66% and 88% of cases on radiology and biopsy, respectively. Tumors measured 6 to 20 cm and, in 402 cases, showed "usual" histology comprising uniformly scattered multinucleate giant cells amidst mononuclear stromal cells, together imparting a syncitium-like appearance. Presence of osteoid, hemorrhage, and aneurysmal bone cyst-like areas; spindle cells in sheets (devoid of giant cells); or storiform pattern and intravascular osteoclasts were less common. The less common histologic features posed diagnostic difficulty in the setting of a small biopsy. Treatment included intralesional curettage (33.19%), marginal excision (4.2%), wide excision (31%), or radical surgeries (14.25%). Recurrences seen in 170 cases were multiple in 47 cases. Metastases largely to the lung were recorded in 24 cases. The histology of all the tumors, namely, primary, recurrent, or metastatic was identical. Statistical analysis using the computer software SPSS (SPSS Inc, Chicago, Ill)was performed with particular reference to the unusual histologic features vs recurrence and metastasis by chi(2) test. The only statistically significant factors were occurrence in the axial skeleton vs appendicular skeleton (P = .001) and primary treatment elsewhere vs at this hospital (P = .045), each of these being associated with increased frequency for local recurrence but not metastasis.

Successful percutaneous treatment of anomalous left coronary artery from pulmonary artery

Anomalous origin of the left main coronary artery from the pulmonary artery (ALCAPA) is an uncommon congenital condition seen in the adult population, with most patients developing symptoms in infancy. We describe successful closure of an ALCAPA in an adult using a percutaneous transcatheter approach in a patient with evidence of anterior wall ischemia believed to be the consequence of myocardial steal. A 30-year-old female was noted to have continuous flow in the right ventricular septum on transthoracic echocardiography, with subsequent imaging confirming the presence of an ALCAPA. Myocardial perfusion imaging confirmed anterior wall ischemia, and as a strategy to optimize coronary perfusion pressure, the patient underwent percutaneous ALCAPA closure using an Amplatzer vascular plug. The procedure was well tolerated, with no evidence of anterior ischemia or myocardial dysfunction. Follow up perfusion imaging demonstrated no residual anterior wall ischemia. Transcatheter closure of an ALCAPA is a potentially safe and effective alternative treatment strategy in this patient population.

MR perfusion and delayed enhancement imaging in the heart

Cardiac magnetic resonance imaging is rapidly emerging as an exciting and important technique for the investigation of congenital and acquired heart disease. This article focuses in particular on recent developments in the field of adenosine stress myocardial perfusion as well as addressing the many applications of 'delayed enhancement' imaging.

Prospective randomized clinical trial of the value of intraperitoneal drainage after pancreatic resection

OBJECTIVE

To test the hypothesis that routine intraperitoneal drainage is not required after pancreatic resection.

SUMMARY BACKGROUND DATA

The use of surgically placed intraperitoneal drains has been considered routine after pancreatic resection. Recent studies have suggested that for other major upper abdominal resections, routine postoperative drainage is not required and may be associated with an increased complication rate.

METHODS

After informed consent, eligible patients with peripancreatic tumors were randomized during surgery either to have no drains placed or to have closed suction drainage placed in a standardized fashion after pancreatic resection. Clinical, pathologic, and surgical details were recorded.

RESULTS

One hundred seventy-nine patients were enrolled in the study, 90 women and 89 men. Mean age was 65.4 years (range 23-87). The pancreas was the tumor site in 142 (79%) patients, with the ampulla (n = 24), duodenum (n = 10), and distal common bile duct (n = 3) accounting for the remainder. A pancreaticoduodenectomy was performed in 139 patients and a distal pancreatectomy in 40 cases. Eighty-eight patients were randomized to have drains placed. Demographic, surgical, and pathologic details were similar between both groups. The overall 30-day death rate was 2% (n = 4). A postoperative complication occurred during the initial admission in 107 patients (59%). There was no significant difference in the number or type of complications between groups. In the drained group, 11 patients (12.5%) developed a pancreatic fistula. Patients with a drain were more likely to develop a significant intraabdominal abscess, collection, or fistula.

CONCLUSION

This randomized prospective clinical trial failed to show a reduction in the number of deaths or complications with the addition of surgical intraperitoneal closed suction drainage after pancreatic resection. The data suggest that the presence of drains failed to reduce either the need for interventional radiologic drainage or surgical exploration for intraabdominal sepsis. Based on these results, closed suction drainage should not be considered mandatory or standard after pancreatic resection.

Cardiopulmonary exercise performance in adult survivors of the Mustard procedure

Most patients with the Mustard procedure are now adults. To date, however, there have been few reports on resting and exercise hemodynamics in a large population of adults with this circulation. The aim of this study is to describe such parameters in one of the largest and oldest populations of adults with the Mustard procedure. The database of the University of Toronto Congenital Cardiac Centre for Adults was examined to identify 84 adults with the Mustard procedure who have undergone cardiopulmonary exercise tests. Magnetic resonance imaging and echocardiography studies were obtained in order to assess right ventricular size, function and baseline hemodynamics. Patients achieved lower maximum uptake of oxygen, maximal heart rate, forced vital capacity, forced expiratory volume in 1 second, and oxygen saturations at maximal exercise compared to a healthy population. Magnetic resonance imaging showed significantly different right ventricular ejection fractions between patients and controls. There were no effects of operative variables or preoperative hemodynamics on current exercise capacity. Patients after the Mustard procedure have subnormal exercise capacities. Factors such as chronotropic incompetence, peripheral deconditioning, and impaired lung function may be responsible for these results.

Angiotensin-converting enzyme inhibitors in adults after the Mustard procedure

Angiotensin-converting enzyme inhibitors had no significant effect on cardiopulmonary exercise function in 14 patients who had undergone a Mustard operation for transposition of the great arteries. In some patients aerobic capacity improved and maximum systolic blood pressure decreased.

Lymphoproliferative disorders after liver transplantation: imaging features

BACKGROUND

To define the imaging features of lymphoproliferative disorders that occur after liver transplantation.

METHODS

A retrospective review of 605 liver transplantations between 1985 and 1998 showed 20 patients with posttransplantation lymphoproliferative disorders (PTLDs). All relevant clinical, imaging, and pathologic findings were reviewed.

RESULTS

PTLDs occurred in 13 men and seven women (mean age = 43.3 years, age range = 18-68 years). The time to diagnosis of disease ranged from 1.5 to 51 months (mean = 14 months) posttransplantation. Cervical, thoracic, or abdominal lymphadenopathy was seen in 11 patients (55%). A complex portal mass in five patients (25%) was the second most common manifestation of PTLD, ranging in size from 5 to 12 cm. Other findings included gastrointestinal tract involvement in three patients (15%) seen as a duodenal mass and diffuse wall thickening in one patient and large bowel thickening in two patients with preexisting inflammatory bowel disease.

CONCLUSION

There is a wide spectrum of findings in lymphoproliferative disorder after liver transplantation. The presence of lymphadenopathy, a portal mass, or bowel thickening indicates a need for further investigation to reach a pathologic diagnosis.

Giant bronchial carcinoid tumors: a multidisciplinary approach

BACKGROUND

Bronchial carcinoid tumors account for approximately 2% of all lung tumors. Although they were considered benign lesions, they are now categorized malignant, occasionally with poor prognosis. The clinical symptoms can be highly variable and are often present for many years before diagnosis. Whereas some carcinoids are entirely asymptomatic, others are accompanied by carcinoid or paraneoplastic syndromes.

METHODS

We describe the multidisciplinary management of a 34-year-old female patient with a massive actively secreting bronchial carcinoid tumor of the right lung. Furthermore, we provide a review of the literature regarding the operative treatment and the perioperative management of pulmonary carcinoid tumors with respect to surgical, anesthetic, radiologic, and pathologic considerations.

RESULTS

In the reported case, the first symptoms were chronic watery diarrhea, skin flushing, progressive shortness of breath, and increasing right shoulder pain. When the patient initially presented at our institution, the tumor had already reached an enormous size and it involved the right and left atrium as well as the atrial septum. Using an evidence-based, multidisciplinary approach the patient was treated successfully with extended surgical resection.

CONCLUSIONS

Carcinoid tumors are potentially curable even if they reach a significant size and thus an aggressive strategy is warranted. The management of such cases requires careful investigation, planning, and treatment with collaborative expertise provided by a multidisciplinary team. We demonstrated that this approach can lead to a favorable outcome in what first appeared to be a formidable and unresectable tumor.

Late arrhythmia in adults with the mustard procedure for transposition of great arteries: a surrogate marker for right ventricular dysfunction?

OBJECTIVE

To examine the relation between ventricular dysfunction and late clinical arrhythmia in adults who underwent the Mustard procedure for transposition of the great arteries.

DESIGN

Observational study based on periodic outpatient assessment of biventricular function.

SETTING

Tertiary referral centre.

INTERVENTIONS

Analysis of data from 12 lead ECGs, echocardiography, exercise radionuclide ventriculography, and magnetic resonance imaging.

MAIN OUTCOME MEASURES

Clinical outcome and late onset clinical arrhythmia during follow up. ECG and ventricular function indices obtained before arrhythmia onset were used for analysis.

RESULTS

51 patients (mean (SD) age 25.7 (5.0) years) fulfilled entry criteria at a mean of 23.4 (4.0) years after the Mustard procedure. Late arrhythmia occurred in 11 (22%): sustained atrial flutter/fibrillation in 10, ventricular tachycardia in one. Compared with patients who remained arrhythmia free, patients with arrhythmia had longer QRS (129 (26) v 112 (16) ms, p = 0.01), greater QT dispersion (107 (28) v 51 (24) ms, p < 0.001), and increased ratio of right to left ventricular end diastolic diameter (2.4 (0.9) v 1.7 (0.7), p = 0.02), but no difference in wall thickness. Systemic ejection fraction was also reduced in the arrhythmia subgroup (at rest: 34.1 (13)% v 47 (16)%, p = 0.04; during exercise: 37.8 (12)% v 52 (17)%, p = 0.03). QRS duration correlated with right ventricular end diastolic diameter (r = 0.59, p < 0.001), suggesting a possible mechano-electric relation after the Mustard procedure. QT dispersion was the only predictor of clinical arrhythmia in multivariate analysis.

CONCLUSIONS

Impaired ventricular function in adults with the Mustard procedure for transposition of the great arteries relates to clinical arrhythmia. Late atrial flutter/fibrillation may be a surrogate marker for ventricular dysfunction, and these patients may also be at risk of ventricular tachycardia.

MRI of the pulmonary veins: comparison between 3D MR angiography and T1-weighted spin echo

OBJECTIVE

The purpose was to determine the ability of three-dimensional (3D) magnetic resonance (MR) angiography to depict normal pulmonary veins in comparison with spin-echo MR imaging.

MATERIALS AND METHODS

MR imaging of 40 patients with cardiovascular disease were reviewed. Patients with known pulmonary venous abnormalities were excluded. Using a standard GE 1.5-T magnet, axial T1-weighted spin-echo 5-mm-thick contiguous slices and 3D MR angiography (contiguous slice thickness of 2.5-3.5 mm, 20-30 c.c. of gadolinium bolus at 1-1.5 c.c./sec, 32-43-second breath-hold, coronal and sagittal plane acquisition) were evaluated retrospectively on separate occasions by two experienced radiologists. Multiplanar imaging projection was used for the identification of pulmonary veins. Each lung was considered to have two drainage veins: a superior vein and an inferior vein. Identification of a pulmonary vein was made by visualizing a connection with the left atrium.

RESULTS

143 pulmonary veins (87.5% +/-5.2) were identified at the level of the left atrium on T1-weighted spin-echo images, and 157 (98.1% +/-1.9) were identified on 3D MR angiography (p<0.01). Overall we identified by T -weighted spin-echo imaging 36 right upper, 38 right lower, 27 left upper, and 38 left lower pulmonary veins. By 3D MR angiography, we identified 38 right upper, 40 right lower, 39 left upper, and 40 left lower pulmonary veins. All four pulmonary veins were detected in 22 patients on spin-echo imaging (55%) and in 37 patients (92.5%) on 3D MR angiography (chi = 3.81, p<0.05).

CONCLUSION

A significant difference is demonstrated between 3D MR angiography and spin-echo MR imaging in identifying normal pulmonary veins. MR angiography provides a complete view of normal pulmonary venous anatomy and could be a valuable tool for the assessment of abnormal pulmonary venous drainage.

Complications of total hip arthroplasty: MR imaging-initial experience

PURPOSE

To investigate the use of standard magnetic resonance (MR) imaging sequences with simple parameter modifications for the detection and characterization of total hip arthroplasty (THA) complications.

MATERIALS AND METHODS

An initial phantom study was performed with cobalt-chrome and titanium prostheses to establish the imaging parameters for a subsequent clinical study. In the clinical study, coronal and transverse MR imaging of 14 THA prostheses was performed before and after intravenous contrast material administration in 12 patients who were being considered for revision arthroplasty. The images were reviewed for evidence of juxtaarticular or periprosthetic abnormalities, patterns of contrast enhancement, and quality of periprosthetic tissue depiction.

RESULTS

Phantom study results showed improved periprosthetic tissue depiction with use of thin sections, increased frequency-encoding gradient strength, and fast spin-echo sequences. The clinical study results demonstrated periprosthetic abnormalities in 11 cases: mechanical loosening in two cases (including one case with an associated periprosthetic fracture); granulomatosis, eight; and infection, one. In 100% of cases, tissue depiction around the femoral component was judged to be of "diagnostic quality." Tissue depiction around the acetabular component was of diagnostic quality in five (36%) cases. In all seven surgically confirmed cases, a correct diagnosis was made preoperatively with MR imaging.

CONCLUSION

By using simple modifications to standard MR imaging sequences, diagnostic-quality MR imaging of THA complications can be performed, particularly around the femoral prosthetic stem.

Isolated congenital absence of the pericardium: clinical presentation, diagnosis, and management

BACKGROUND

Congenital absence of the pericardium (CAP) is a rare clinical entity.

METHODS

We identified from the two hospital databases all patients with isolated CAP, reviewed their data, and invited them for prospective clinical evaluation with electrocardiography, chest x-ray findings (CXR), echocardiography, and magnetic resonance imaging (MRI).

RESULTS

Ten patients (3 males, 7 females) presented at a median age of 21 years (range, 2-53 years) with paroxysmal stabbing chest pain, largely nonexertional (9), and heart murmur with an abnormal CXR (1). Three patients had partial and 7 had complete CAP (all 7 had marked lateral displacement of the cardiac apex). CXR combined with MRI were key to establishing the diagnosis; a "tongue" of lung tissue interposing between the main pulmonary artery and aorta was the most consistent diagnostic feature. Four patients underwent pericardioplasty, 3 for debilitating symptoms and 1 for left atrial appendage herniation, followed by improvement or resolution of symptoms. At a mean of 10.5 years from presentation all patients were alive. No complications were seen in the nonsurgical group.

CONCLUSIONS

Isolated CAP has a common presentation pattern with periodic stabbing chest pain mimicking coronary artery disease. CXR and MRI are required for definitive diagnosis. Symptomatic patients with the complete form may benefit from pericardioplasty.

Intracardiac extension of intravenous leiomyomatosis in a pregnant woman: A case report and review of the literature

Intravenous leiomyomatosis is an uncommon clinical entity characterized by the growth of a benign, smooth muscle tumour within the venous system. Intracardiac extension of this tumour is rare, and approximately 35 cases have been reported in the literature. The second case of massive intracardiac extension of intravenous leiomyomatosis is reported in a pregnant patient diagnosed after the unusual presentation of seizure activity. Tumours were successfully removed from the right internal iliac vein, inferior vena cava, and right atrium and ventricle in a single-stage operation using cardiopulmonary bypass and circulatory arrest. Concomitant total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Nine months after diagnosis, the patient was evaluated for recurrent disease. A review of the literature from 1994 to 1998 is presented.

Intracardiac extension of intravenous leiomyomatosis in a pregnant woman: A case report and review of the literature

Intravenous leiomyomatosis is an uncommon clinical entity characterized by the growth of a benign, smooth muscle tumour within the venous system. Intracardiac extension of this tumour is rare, and approximately 35 cases have been reported in the literature. The second case of massive intracardiac extension of intravenous leiomyomatosis is reported in a pregnant patient diagnosed after the unusual presentation of seizure activity. Tumours were successfully removed from the right internal iliac vein, inferior vena cava, and right atrium and ventricle in a single-stage operation using cardiopulmonary bypass and circulatory arrest. Concomitant total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Nine months after diagnosis, the patient was evaluated for recurrent disease. A review of the literature from 1994 to 1998 is presented.

Primary pericardial mesothelioma presenting as constrictive pericarditis

Primary pericardial mesothelioma is a rare tumour, often discovered late in a patient's clinical course or at autopsy. Antemortem diagnosis is usually made at the time of surgery. A patient who presented with what appeared to be viral pericarditis in October 1997 is reported. Recurrent symptoms prompted re-evaluation with echocardiography, chest computed tomography, magnetic resonance imaging, cardiac catheterization and a diagnosis of constrictive pericarditis. Associated hepatic dysfunction was found to be secondary to congestion. After operative pericardiotomy and histological examination, primary pericardial mesothelioma was diagnosed. The lesion was surgically debulked.

Coronary venous oximetry using MRI

Based on the Fick law, coronary venous blood oxygen measurements have value for assessing functional parameters such as the coronary flow reserve. At present, the application of this measure is restricted by its invasive nature. This report describes the design and testing of a noninvasive coronary venous blood oxygen measurement using MRI, with a preliminary focus on the coronary sinus. After design optimization including a four-coil phased array and an optimal set of data acquisition parameters, quality tests indicate measurement precision on the order of the gold standard optical measurement (3%O(2)). Comparative studies using catheter sampling suggest reasonable accuracy (3 subjects), with variability dominated by sampling location uncertainty ( approximately 7%O(2)). Intravenous dipyridamole (5 subjects) induces significant changes in sinus blood oxygenation (22 +/- 9% O(2)), corresponding to flow reserves of 1.8 +/- 0.4, suggesting the potential for clinical utility. Underestimation of flow reserve is dominated by right atrial mixing and the systemic effects of dipyridamole. Magn Reson Med 42:837-848, 1999.

Safety and efficacy of low anterior resection for rectal cancer: 681 consecutive cases from a specialty service

OBJECTIVE

To determine perioperative morbidity, survival, and local failure rates in a large group of consecutive patients with rectal cancer undergoing low anterior resection by multiple surgeons on a specialty service. The primary objective was to assess the surgical complications associated with preoperative radiation sequencing.

SUMMARY BACKGROUND DATA

The goals in the treatment of rectal cancer are cure, local control, and preservation of sphincter, sexual, and bladder function. Surgical resection using sharp perimesorectal dissection is important for achieving these goals. The complications and mortality rate of this surgical strategy, particularly in the setting of preoperative chemoradiation, have not been well defined.

METHODS

There were 1233 patients with primary rectal cancer treated at the authors' cancer center from 1987 to 1995. Of these, 681 underwent low anterior resection and/or coloanal anastomosis for primary rectal cancer. The surgical technique used the principles of sharp perimesorectal excision. Morbidity and mortality rates were compared between patients receiving preoperative chemoradiation (Preop RT, n = 150) and those not receiving preoperative chemoradiation (No Preop RT, n = 531). Recurrence and survival data were determined in patients undergoing curative resection (n = 583, 86%) among three groups of patients: those receiving Preop RT (n = 131), those receiving postoperative chemoradiation (Postop RT, n = 110), and those receiving no radiation therapy (No RT, n = 342).

RESULTS

The perioperative mortality rate was 0.6% (4/681). Postoperative complications occurred in 22% (153/681). The operative time, estimated blood loss, and rate of pelvic abscess formation without associated leak were higher in the Preop RT group than the No Preop RT group. However, the overall complication rate, rate of wound infection, anastomotic leak, and length of hospital stay were no different between Preop RT and No Preop RT patients. With a median follow-up of 45.6 months, the overall actuarial 5-year recurrence rate for patients undergoing curative resection (n = 583) was 19%, with 4% having local recurrence only, 12% having distant recurrence, and 3% having both local and distant recurrence, for an overall local recurrence rate of 7%. The actuarial 5-year overall survival rate was 81%; the disease-free survival rate was 75% and the local recurrence rate was 10%. The overall survival rate was similar between Preop RT (85%), Postop RT (72%), and No RT (83%) patients (p = 0.10), whereas the disease-free survival rate was significantly worse for Postop RT (65%) patients compared with Preop RT (79%) and No RT (77%) patients (p = 0.04).

CONCLUSION

The use of preoperative chemoradiation results in increased operative time, blood loss, and pelvic abscess formation but does not increase the rate of anastomotic leaks or the length of hospital stay after low anterior resection for rectal cancer. The 5-year actuarial overall survival rate for patients undergoing curative resection exceeded 80%, with a local recurrence rate of 10%.

The value of late computed tomographic scanning in identification of vascular abnormalities after abdominal aortic aneurysm repair

PURPOSE

The purpose of this study was to determine the prevalence of late arterial abnormalities after aortic aneurysm repair and thus to suggest a routine for postoperative radiologic follow-up examination and to establish reference criteria for endovascular repair.

METHODS

Computed tomographic (CT) scan follow-up examination was obtained at 8 to 9 years after abdominal aortic aneurysm (AAA) repair on a cohort of patients enrolled in the Canadian Aneurysm Study. The original registry consisted of 680 patients who underwent repair of nonruptured AAA. When the request for CT scan follow-up examination was sent in 1994, 251 patients were alive and potentially available for CT scan follow-up examination and 94 patients agreed to undergo abdominal and thoracic CT scanning procedures. Each scan was interpreted independently by two vascular radiologists.

RESULTS

For analysis, the aorta was divided into five defined segments and an aneurysm was defined as a more than 50% enlargement from the expected normal value as defined in the reporting standards for aneurysms. With this strict definition, 64.9% of patients had aneurysmal dilatation and the abnormality was considered as a possible indication for surgical repair in 13.8%. Of the 39 patients who underwent initial repair with a tube graft, 12 (30.8%) were found to have an iliac aneurysm and six of these aneurysms (15.4%) were of possible surgical significance. Graft dilatation was observed from the time of operation (median graft size of 18 mm) to a median size of 22 mm as measured by means of CT scanning at follow-up examination. Fluid or thrombus was seen around the graft in 28% of the cases, and bowel was believed to be intimately associated with the graft in 7%.

CONCLUSION

Late follow-up CT scans after AAA repair often show vascular abnormalities. Most of these abnormalities are not clinically significant, but, in 13.8% of patients, the thoracic or abdominal aortic segment was aneurysmal and, in 15.4% of patients who underwent tube graft placement, one of the iliac arteries was significantly abnormal to warrant consideration for surgical repair. On the basis of these findings, a routine CT follow-up examination after 5 years is recommended. This study provides a population-based study for comparison with the results of endovascular repair.