Subclinical cerebral complications after coronary artery bypass grafting: prospective analysis with magnetic resonance imaging, quantitative electroencephalography, and neuropsychological assessment.

OBJECTIVE: To analyze the frequency and severity of subclinical cerebral complications associated with coronary artery bypass grafting (CABG). DESIGN: A prospective controlled study using preoperative and postoperative magnetic resonance imaging (MRI) of the brain, quantitative electroencephalography (QEEG), and detailed neuropsychological and neurologic examinations as potentially sensitive indicators of subclinical cerebral injury associated with CABG. SETTING: Multimodality evaluation in a tertiary care unit (Kuopio University Hospital, Kuopio, Finland). PATIENTS: Thirty-eight patients undergoing elective CABG and 20 control patients undergoing other major vascular surgery, mostly operations on the abdominal aorta. MAIN OUTCOME MEASURES: Coronary artery bypass grafting-associated cerebral complications assessed preoperatively and postoperatively by brain MRI, QEEG, detailed neurologic examination, and a neuropsychological test battery that evaluates cognitive functions in major areas known to be vulnerable to organic impairment (learning and memory, attention, flexible mental processing, and psychomotor speed). RESULTS: There were no major neurologic complications. A mild hemisyndrome developed in 1 patient who underwent CABG and in 1 control patient. Overall, there was no decline in mean cognitive performance 3 months after surgery. Electroencephalographic slowing of 0.5 Hz or more in at least 2 channels occurred in 11 patients who underwent CABG and in 1 control patient (P=.03). The postoperative brain MRI scan revealed new small ischemic lesions in 8 patients (21%) in the CABG group but in none of the control group (P=.03). These new cerebral MRI lesions did not explain deterioration in neuropsychological test performance or the QEEG slowing. CONCLUSIONS: Coronary artery bypass grafting causes more QEEG alterations and small ischemic cerebral lesions that are detectable by MRI than does other major vascular surgery. The effect is mainly subclinical, because no statistically significant deterioration in mean neuropsychological test performance was detected.

Non-suppressed thyrotropin and elevated thyroglobulin are independent predictors of recurrence in differentiated thyroid carcinoma.

OBJECTIVE: Although in most cases differentiated thyroid carcinoma (DTC) responds to surgery and radioiodine (RaI) therapy, some patients will have recurrence and eventually cancer-related death. However, although various prognostic factors of DTC have been identified (e.g. staging, suppressed thyrotropin), none of the previous studies have assessed simultaneously their role in multivariate analysis. DESIGN AND METHODS: In this retrospective population-based study, we reviewed the clinicopathological data of 254 DTC patients treated in eastern Finland during the years 1976-1995, for clinical characteristics, primary treatment, follow-up and cancer recurrence. Tumor stage was based on pathological tumor-node-metastasis (pTNM) classification, and histopathological specimens were re-evaluated. RESULTS: DTC recurrence occurred in 33 patients (13%). In univariate analyses, the predictors of recurrence were older age (>60 years, P<0.05), follicular tumor type (P<0.01), pTNM classification system (P<0.05) and post-ablative radioiodine uptake outside the neck (P<0.05). Non-suppressed serum thyrotropin (TSH) and elevated serum thyroglobulin (>3 microg/l) measured one year after operation were both related to tumor recurrence (P<0.05 and P<0.001 respectively). In multivariate analysis the independent predictors for recurrence were both elevated thyroglobulin (P<0.001) and non-suppressed TSH (P<0.05) independent of histology, pTNM stage and RaI uptake. Adjusted risk ratio for recurrence of DTC for unsuppressed thyrotropin was 2.3, for elevated thyroglobulin 14.0 and, if both conditions were present, the risk ratio increased to 45.1. CONCLUSION: Our results suggest that both non-suppressed serum TSH and elevated serum thyroglobulin are related to an increased risk of DTC recurrence independent of tumor type and pTNM stage.

Hypermetabolism after coronary artery bypass.

We measured the changes in energy expenditure in the early postoperative phase after coronary artery bypass operations and the ventilatory response to the increased demand for respiratory gas exchange. Breathing pattern and gas exchange were measured noninvasively by respiratory inductive plethysmography and indirect calorimetry with a canopy. Eighteen patients were studied after weaning from mechanical ventilation. Energy expenditure increased by 18.3%, which is comparable to the response to major injury. Carbon dioxide production increased from 162 +/- 20 to 195 +/- 36 ml/min in the supine position (p less than 0.001), and similar changes were observed in the half-sitting position. Arterial carbon dioxide tension increased marginally (37.5 +/- 2.96 mm Hg preoperatively versus 39.7 +/- 4.87 mm Hg postoperatively; p less than 0.05), while oxygen tension decreased from 89.9 +/- 17.3 mm Hg to 62.9 +/- 13.4 mm Hg (p less than 0.001). Minute ventilation increased by 34% in the supine position (p less than 0.01) and by 28% in the half-sitting position (p less than 0.05), while tidal volume remained unchanged. We conclude that coronary artery bypass operations induce hypermetabolism and substantially increase ventilation and risk of arterial hypoxemia during the phase of compromised cardiovascular reserves.

Intravascular ultrasound and magnetic resonance imaging in the assessment of atherosclerotic lesions in rabbit aorta. Correlation to histopathologic findings.

RATIONALE AND OBJECTIVES: The authors compare the usefulness of intravascular ultrasound (IVUS) and magnetic resonance imaging (MRI) for quantitation of atherosclerosis in hyperlipidemic rabbits, correlated with histopathology. METHODS: Magnetic resonance imaging with T1- and T2-weighted spin echo sequences and three-dimensional time-of-flight MR angiography of the abdominal aorta was performed on seven rabbits using a 1.5 T MR imager and a standard head coil. X-ray angiography and IVUS examination (3.5 F/30 MHz imaging catheter) was performed via carotid artery access. RESULTS: Time-of-flight MR angiography source images provided the best resolution and plaque-lumen contrast in visual comparison between the different MRI sequences. Intra- and interobserver reproducibilities of the lesion thickness and area measurements were similar in IVUS and MRI (Pearson correlations 0.52-0.97; P < 0.01). The measurements from IVUS and MRI correlated closely with each other as well as with those made from histopathologic specimens (Pearson correlations 0.50-0.79; P < 0.001). The measurements from IVUS were somewhat more accurate than those made from MRI. CONCLUSIONS: Both MRI and IVUS with clinically available imaging equipments are feasible and accurate for the quantitation of experimental atherosclerosis of rabbit aorta.

Respiratory changes after open-heart surgery.

Breathing pattern was studied non-invasively in 20 coronary artery bypass surgery patients before the operation and post-operatively after weaning from mechanical ventilation. Post-operatively minute ventilation (VE), breathing frequency (Fr) and mean inspiratory flow (VT/TI) increased (28%, 42%, 27%; p less than 0.01, p less than 0.001, p less than 0.01, respectively), while tidal volume (VT) decreased (15%, p less than 0.025). CO2 production (VCO2) and oxygen consumption (VO2) increased postoperatively (p less than 0.001 for both), contributing to the increase in ventilatory demand. Reduced variation of VT and Fr (p less than 0.001, p less than 0.01, respectively) and number of sighs (p less than 0.001) were characteristic of the post-operative breathing pattern. Post-operatively an increase in the contribution of rib cage (%RC) to tidal volume in the supine position was observed suggesting reduced motion of the diaphragm. All patients had atelectasis, 17 had pleural fluid and only 6 normal vascularity post-operatively. The shallow breathing in combination with increased ventilatory demand, impaired gas exchange and the surgical trauma of the thorax predispose to postoperative respiratory complications.

Breathing pattern and gas exchange in emergency and elective abdominal surgical patients.

OBJECTIVE: To evaluate the effects of intra-abdominal surgical emergency on breathing pattern and gas exchange and compare it with the changes induced by elective abdominal surgery. DESIGN: Prospective clinical study. SETTING: Abdominal surgical departments in a university hospital. PATIENTS: Patients operated for intra-abdominal emergency (n = 10, EAS), elective upper abdominal (n = 19, UAS). MEASUREMENTS AND RESULTS: Breathing pattern and gas exchange were measured with a respiratory inductive plethysmograph and a gas exchange monitor. EAS patients had pre-operatively a classical rapid shallow breathing pattern and increased ventilatory demand due to increased energy expenditure. The operation improved the breathing to normal pattern (frequency, 26 +/- 5/min and 17 +/- 3/min, p < 0.01; tidal volume, 439 +/- 128 ml and 541 +/- 165 ml, NS., before and after surgery, respectively). Sighing was absent before and after EAS and strictly reduced after elective surgery (p < 0.01 for UAS). The operation restricted the abdominal-diaphragmatic breathing movement which was reflected as increased contribution of the rib cage to VT (%RC: from 37% +/- 15 to 57% +/- 15 for UAS p < 0.001; from 47% +/- 16 to 61% +/- 14 for EAS NS.). After EAS and UAS hypoxemia was common (p < 0.001) with frequent radiological pathology. We conclude that intra-abdominal surgical emergencies increase the ventilatory demand and challenge the respiratory system to marked adaptive changes both pre- and post-operatively.

Carotid stenosis by digital subtraction angiography: reproducibility of the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial measurement methods and visual interpretation.

PURPOSE: To evaluate different carotid stenosis estimation methods with digital subtraction angiography. METHODS: We assessed the intraobserver reproducibilty and interobserver variability of visual interpretation and the measurement methods used by the European Carotid Surgery Trial and the North American Symptomatic Carotid Endarterectomy Trial. Angiographic stenosis measurements according to both criteria were performed twice by a radiologist, a neurologist, and a vascular surgeon. Eighty bifurcations of consecutive symptomatic patients underwent 480 pairs of measurements. In addition, four radiologists estimated the stenoses visually. RESULTS: Intraobserver consistency was slightly better by the European (kappa, 0.86 to 0.94) than by the North American (kappa, 0.68 to 0.91) trial criteria or by visual interpretation (kappa, 0.79 to 0.81). No significant interobserver variability was found, except in the subgroup of mild stenoses by the North American Trial criteria. By kappa statistic, the interobserver agreement was excellent by the European trial method (kappa, 0.72 to 0.86), good by the North American trial method (kappa, 0.59 to 0.77), and good to excellent by visual evaluation (kappa, 0.68 to 0.88). The visual estimation agreed more closely with the European (kappa, 0.73 to 0.92) than with the North American trial (kappa, 0.55 to 0.74) criteria measurements. CONCLUSIONS: All three methods have good reproducibility in digital subtraction angiography. Interobserver differences become more important in the estimation of mild stenosis.

Late correlative imaging findings of previous acute infective spondylitis.

PURPOSE: To evaluate late correlative imaging findings in relation to clinical outcome in persons with previous acute infective spondylitis, the authors performed bone and leukocyte scintigraphy (planar and SPECT imaging) and magnetic resonance imaging of the spine in nine patients (two men, seven women; mean age, 66 years; age range, 57 to 84 years) 3.1 years (range, 0.9 to 6.2 years) after the acute disease. METHODS: All images were evaluated visually. The relevant uptake on SPECT images was also quantitated using an adjacent normal vertebral body as the reference area. RESULTS: Except for one patient, all other patients had increased uptake in the affected vertebra on bone scintigraphy [corrected]. In leukocyte scintigraphy, clearly decreased uptake was noted quantitatively in six of the seven patients who underwent SPECT. On the magnetic resonance and computed tomographic scans, the typical findings were destruction of intervertebral disks and compression deformities of vertebral bodies, but there was high interindividual variance of other findings, such as osteophytes, spondylolisthesis, increased vertebral fat content, and postoperative changes. These data show that nearly all patients with previously acute infective spondylitis have gross abnormal anatomic and functional imaging findings years after the acute disease, despite good clinical outcome [corrected]. CONCLUSIONS: The utility of bone and leukocyte scans in the diagnosis of reactivated spondylitis is limited, and incidentally observed abnormal imaging findings in asymptomatic patients with known previous spondylitis should be interpreted with caution.

Functional outcome of distal bypasses for lower limb ischemia.

OBJECTIVES: The purpose of this study was to assess limb salvage and functional outcome in patients who underwent distal reconstructions. DESIGN: Retrospective study. MATERIALS AND METHODS: Fifty-nine consecutive patients underwent 63 femorodistal bypass operations during 1998-2002 at a university hospital. Late functional outcome was assessed using a questionnaire (mean 27 months after the primary operation). RESULTS: At the end of the study, 81% (30/37) of the surviving patients were alive with a viable limb. In all, 90% (27/30) of patients were living in their own homes and 3% (1/30) in a nursing home. Sixty percent (18/30) were able to walk independently. The walking distance was unlimited in 42% (13/31) and limited in 42% (13/31) of the operated limbs. In 16% (5/31) of cases, the treated limbs served only as a support. CONCLUSIONS: According to our results, the functional outcome of distal bypasses seems to be favourable. It is recommended that these operations should be performed even in elderly patients to avoid major amputations and to maintain the independence of the patient.

Ruptured massive aneurysm of the deep femoral artery.

Atherosclerotic aneurysm of the deep femoral artery is extremely rare. We report an 88-year-old man, who was admitted to the hospital because of acute pain and massive swelling in the right groin. Angiography and ultrasonography demonstrated an uncommonly large ruptured deep femoral artery aneurysm (10.5 x 10.1 cm). At operation the aneurysm was resected accompanied by an autogenous venous graft replacement. This case and others reported in the literature indicate operative treatment in all, even in symptomless deep femoral artery aneurysms in order to avoid serious complications.

Axillofemoral bypass operations in Kuopio University Hospital 1985-1996.

BACKGROUND AND AIMS: Axillofemoral bypass has been used since the 1960's in poor-risk patients with aortoiliac atherosclerotic occlusive disease to improve arterial circulation in the lower extremities. This article describes the outcome of 84 consecutive operations in our hospital. MATERIAL AND METHODS: During the period 1.1.1985-31.5.1996, 84 axillofemoral bypass operations were performed in our hospital. In this retrospective study, information was based on patient records and clinical follow-up examination for surviving patients living in the area of Kuopio province and operated before the end of 1995. Patencies and survivals were established using the life table method. RESULTS: The primary patency rate was 81.1 % at one year, 64.3 % at three years and 56.7 % at five years. The secondary patency rates were 92.1%, 67.1% and 57.7 %, respectively. The operative mortality rate was 6.0%. Eighty-five percent of the patients were alive one year after the operation, compared to 50 % after five years. Serious complications were rare, but local wound complications occurred in 29 %. Vascular reoperations were needed in 29 %, particularly thrombectomies. CONCLUSIONS: Axillofemoral bypass gives acceptable results in the treatment of lower leg ischaemia in elderly poor-risk patients.

Compartment syndrome as a late complication of eosinophilic fasciitis.

Eosinophilic fasciitis (EF) was diagnosed in a 23-year-old man presenting characteristic symptoms, skin changes, blood eosinophilia and typical histology showing thickened deep dermal fascia with inflammatory cells. After one year of corticosteroid treatment he experienced increasing pain in both legs and fluctuating serum creatinine kinase levels. Direct measurement showed elevated resting intracompartment pressure and both static strain and dynamic exercise provoked the typical pain. At operation all 4 compartments of both legs were decompressed and he recovered uneventfully. The compartment syndrome may be a hitherto unknown, but expected complication of severe EF.

Vocal cord paralysis caused by a cyst in extraglandular thyroid tissue. Case report.

A 37-year-old woman presented with hoarseness two days after developing pain while undergoing physiotherapy for tension in her neck. Computed tomography showed a probably benign mass near to the left lobe of the thyroid, which was found at operation to be attached to the recurrent laryngeal nerve. The nerve was dissected free, the tumour removed, and the patient and her voice recovered fully. Histological examination confirmed a benign cyst in extraglandular thyroid tissue and the patient is well two years later.

Does the anesthetic method influence the postoperative breathing pattern and gas exchange in hip surgery? A comparison between general and spinal anesthesia.

We studied the effects of elective hip surgery, performed under either spinal (SA, n = 10) or general anesthesia (GA, n = 10), on breathing pattern and gas exchange. Measurements were made with respiratory inductive plethysmograph and indirect calorimetry in two positions before and after surgery. The method of anesthesia had no effect on the severity of postoperative hypoxemia. Reduced arterial oxygenation (PaO2; P less than 0.001, SA from 12.5 +/- 2.37 kPa to 10.5 +/- 1.38 kPa, GA from 12.5 +/- 2.95 kPa to 10.5 +/- 1.75 kPa) despite increased alveolar ventilation (P less than 0.01; from 2.30 +/- 0.37 l/min to 2.39 +/- 0.43 l/min in SA, 2.27 +/- 0.56 l/min to 2.57 +/- 0.35 l/min in GA) and reduced arterial carbon dioxide partial pressure (PaCO2; SA from 5.20 +/- 0.22 kPa to 4.95 +/- 0.33 kPa, P less than 0.01, GA from 5.07 +/- 0.36 kPa to 4.72 +/- 0.41 kPa, P less than 0.05) indicated maldistribution of ventilation and perfusion. Changes in breathing pattern and gas exchange and differences between the groups were minimal. Minute ventilation, tidal volume and mean inspiratory flow remained unchanged in both groups. The contribution of rib cage to tidal volume increased postoperatively in the supine position (P less than 0.001; SA from 32.6% +/- 10.3 to 46.3% +/- 7.5, GA from 36.5 +/- 16.4 to 48.5% +/- 15.4). CO2 production, oxygen consumption and energy expenditure remained unchanged. The postoperative changes in breathing pattern are related to the operation, not to the type of anesthesia and do not explain the alterations in gas exchange.

Results of infrainguinal bypass surgery: an analysis of 263 consecutive operations.

BACKGROUND AND AIMS: The purpose of this clinical study was to assess the success of infrainguinal revascularization in the treatment of lower limb ischaemia. MATERIAL AND METHODS: 226 consecutive patients underwent 263 femoropopliteal (n = 194) or femorodistal (n = 69) bypass operations during 1988-1996 at a university hospital. Records of all patients were reviewed. Late control visits including clinical and colour doppler ultrasound examinations were programmed for 109 patients. Initial success, primary and secondary patencies, limb salvage and survival rates were determined and factors affecting outcome were analysed in various patient categories. RESULTS: Initial success rate was 92% (243/263). The primary and secondary patencies were 70/83% and 52/63% at one and five years, respectively. The corresponding limb salvage rates for patients with chronic critical ischaemia were 82% and 77%. The number of diseased vessels in the treated limb correlated negatively with the primary patency. Advanced age did not affect primary patency or limb salvage rates. Diabetes and the use of distal revascularizations were independent predictors of poorer limb salvage. Diabetes and renal insufficiency proved to shorten life expectancy. CONCLUSIONS: Infrainguinal revascularizations are effective regardless of patient's age. The extent of atherosclerotic changes in the operated limb, diabetes and renal insufficiency are factors affecting outcome.

How should we estimate carotid stenosis using magnetic resonance angiography?

Our purpose was to assess the reproducibility of and differences between the most commonly used methods for assessing carotid artery stenosis using magnetic resonance angiography (MRA). We studied 55 patients who underwent axial three-dimensional time-of-flight MRA (1.5 T). Quantitative caliper measurements were performed from maximum intensity projection (MIP) and multiple planar reconstruction (MPR) images, according to the criteria of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST). The measurements were compared to each other and to visual interpretation, using conventional angiography as the reference. The measured percentage stenoses were higher on MRA than on digital subtraction angiography (DSA) using both NASCET (mean difference 1.9-3.0%) and ECST (6.3-6.7%) criteria. The kappa coefficients for the agreement between DSA and MRA were higher using the NASCET (0.61-0.76) than the ECST criteria (0.52-0.65). No statistically significant differences were found between measurements from MIP and MPR images. The ECST measurement criteria gave significantly higher percentage stenoses than the NASCET criteria (P < 0.001), this difference being more prominent on MRA (mean difference in diameter stenosis percentage 14.3-16.4%) than on DSA (7.6-11.2%) and most important with mild stenoses. The difference between visual interpretation and quantitative measurements on MRA was significant (P = 0.01-0.001). There were no statistically significant interobserver differences in the MRA film readings, either in visually estimated degrees of stenosis or stenosis measurements. Thus, the different criteria of the two multicentre trials led to significantly different results, especially in the assessment of mild stenosis, and these differences are more important with MRA than with DSA. Differences between the imaging modalities or the reconstruction programs seem less important.

Hemodynamic effects of carotid endarterectomy by magnetic resonance flow quantification.

BACKGROUND AND PURPOSE: Blood flow can be evaluated non-invasively using magnetic resonance phase-contrast flow quantification. The purpose of this prospective study was to assess the feasibility of this method and to evaluate the hemodynamic effects of carotid endarterectomy. METHODS: Volumetric flow rates and peak systolic velocities of the internal and common carotid and the vertebral arteries were measured by magnetic resonance flow quantification. Sixteen patients undergoing 18 endarterectomies had complete flow data recorded preoperatively and 3 days after surgery. RESULTS: The inverse correlation between the angiographic stenosis degree and the preoperative flow rate in the corresponding internal carotid artery was highly significant (r = -.69, P < .001). After endarterectomy, the mean flow in the ipsilateral internal carotid artery improved from 143 to 233 mL/min (P < .001). The mean peak systolic velocity increased from 23 to 37 cm/s (P < .001). No significant changes were seen in the contralateral carotid or the vertebral arteries. The mean total blood flow improved by 81 mL/min (P = .08). In the severely stenosed bifurcations (70% to 99%, n = 11), the flow rate improved by 106 mL/min and in the moderately (30% to 69%, n = 4) or mildly (< 30%, n = 3) stenosed bifurcations by 63 mL/min. If the contralateral carotid artery was occluded or severely stenosed, the improvement was 164 mL/min. CONCLUSIONS: Magnetic resonance flow quantification provides a useful tool for the follow-up of the hemodynamic effects of carotid endarterectomy. Our results indicate that surgery is followed by a significant increase of blood flow in the ipsilateral carotid artery and that there appear to be differences in flow increase between subgroups of patients with different degrees of stenosis.

Reduced CD44 standard expression is associated with tumour recurrence and unfavourable outcome in differentiated thyroid carcinoma.

CD44 was detected with an antibody recognizing all forms of CD44 (CD44 standard) and others specific for its v3 and v6 variant isoforms; their prognostic value was evaluated in 213 patients with differentiated thyroid carcinoma (DTC). The staining patterns of CD44 standard (s) and CD44v6 in tumour tissue were quite similar, 176 cases (83%) being highly positive for CD44s and 153 cases (72%) for CD44v6. Only 18 (9%) tumours showed high expression of CD44v3. Papillary carcinomas were significantly more often high expressors of CD44s and CD44v6 than follicular carcinomas (p<0.001 for both). Age older than 60 years, distant metastases, and advanced pTNM stage were related to loss of expression of CD44s (p<0.001, p=0.021, and p=0.003, respectively). Tumour recurrence and cancer-related mortality were related to the reduced level of CD44s (p=0.049 and p=0.042). CD44v3 did not associate with any of the clinicopathological factors. In univariate analysis, CD44s was the only significant prognostic factor for disease-free survival (p=0.0488). In multivariate analysis, CD44s and thyroglobulin level were significant prognostic factors for disease-free survival (p=0.040 and p<0.001, respectively). The reduced level of CD44s in DTC patients seems to be an independent prognostic factor for unfavourable disease outcome.