Risk factors for stroke following coronary artery bypass operations

BACKGROUND: Although the overall complication rates have been decreased significantly in recent years, stroke rates still remain high in patients undergoing coronary bypass operations. This study is designed to evaluate the risk factors for stroke in patients who had undergone coronary artery bypass surgery in an 8-year period in our clinic. METHODS: Between 1995 and 2003, 8547 coronary artery operations under cardiopulmonary bypass were performed. Retrospective analysis of the patient files revealed that 75 (0.9%) patients had stroke in the early postoperative period. RESULTS: Mean age of these patients was 62.3 +/- 9.5 years, and 54 (72%) were males. Stroke rate was 1.2% between 1995 and 1998 and this was significantly higher from the stroke rate (0.7%) of the period 1998 to 2003 (p = 0.03). Major technical differences between these two periods were the routine application of preoperative carotid arteries Doppler evaluation and intraoperative epiaortic echocardiography after 1998. Higher age (p = 0.000), female sex (p = 0.005), smoking (p = 0.03), presence of diabetes mellitus (p = 0.01), hypertension (p = 0.008), and left main coronary artery disease (p = 0.001), carotid surgery (p = 0.000), and peripheral vascular disease (p = 0.049) were identified as important risk factors in univariate analysis for stroke development. Higher age (p = 0.000; OR = 21.38), left main coronary artery disease (p = 0.007; OR = 7.26), peripheral vascular disease (p = 0.050; OR = 3.08), and operation date before 1998 (p = 0.012; OR = 6.33) were identified as important risk factors in logistic regression analysis. According to intraoperative epiaortic ultrasonography, operative strategy was changed in 9% of patients. Thirty-seven (49.3%) of the stroke patients died. Female sex (p = 0.023; OR = 5.18) and preoperative hypertension (p = 0.045; OR = 4.03) were observed as significant risk factors for mortality after stroke. CONCLUSION: Development of stroke is one of the major reasons of mortality after coronary artery bypass operations. It is essential to take all the measures to prevent this complication, especially in patients with known risk factors. Evaluation of carotid arteries prior to operation and application of routine intraoperative epiaortic echocardiography may in part eliminate stroke.     

Nitric oxide modulates renal vasoconstrictor effect of endothelin-1 in conscious lambs

To test the hypothesis that nitric oxide (NO) buffers the renal vasoconstrictor effects of endothelin-1 (ET-1) early in life, renal haemodynamic responses to ET-1 were measured in the presence and absence of endogenously produced NO in conscious lambs. Renal haemodynamic effects of ET-1 were measured for 5 min before (control) and 20 min after intraarterial injection of ET-1 before and after pretreatment with 20 mg/kg of the l-arginine analogue N^G-nitro-l-arginine methyl ester (l-NAME), (experiment 1) and its inactive isomer D-NAME (experiment 2) in conscious lambs aged ~1 week (N=7) and ~6 weeks (N=6). The two experiments were carried out in random order at intervals of 24–48 h. In lambs aged ~6 weeks, a marked increase in renal vascular resistance (RVR) was elicited by ET-1 administration; this response was enhanced twofold following pretreatment with l-NAME. In 1-week-old lambs, however, an increase in RVR in response to ET-1 occurred only after pretreatment with l-NAME. Therefore, we accept our hypothesis and conclude that NO buffers the renal vasoconstrictor effects of ET-1 early in life.The current address of Dr. Liesbeth van der Velde is UCLA Medical Center, Los Angeles, CA, USA. The current address of Dr. Alp Sener is University of Western Ontario, London, ON, Canada     

Glenohumeral instability and arthrosis

Although the development of arthrosis is rare following shoulder dislocations, it represents a significant problem if it develops after surgery for shoulder instability. The incidence of arthrosis may be decreased by correct diagnosis of the instability and appropriate surgical technique. However, should it occur, shoulder arthroplasty should be considered.     

Do platelet apoptosis, activation, aggregation, lipid peroxidation and platelet-leukocyte aggregate formation occur simultaneously in hyperlipidemia?

OBJECTIVES: The circulating lipoproteins may cause some abnormalities in platelet composition and function in hypercholesterolemia. The aim of this study was to investigate whether platelet apoptosis, platelet activation, platelet aggregation, platelet-leukocyte aggregate (PLA) formation and lipid peroxidation occur simultaneously in hyperlipidemia. DESIGN AND METHODS: Expression of GpIIb/IIIa (CD41a), P-selectin (CD62-P), platelet-bound fibrinogen (antifibrinogen), platelet membrane phosphatidylserine (PS), platelet-monocyte aggregates (mono-PLA) and platelet-neutrophil aggregates (neut-PLA) was measured in eight hyperlipidemic and eight normal subjects using flow cytometry. ADP (10 microM) was used to activate platelets. Furthermore, ADP induced platelet aggregation responses, platelet malondialdehyde (MDA) and glutathione (GSH) levels were determined. RESULTS: Before platelet activation, platelet CD62-P, antifibrinogen, annexin-V, mono-PLA, neut-PLA and platelet MDA levels as well as platelet aggregation responses in the hyperlipidemics were significantly higher than those in the controls (P<0.01, P<0.01, P<0.01, P<0.001, P<0.001, P<0.01, P<0.001, respectively), whereas GpIIb/IIIa expression and GSH levels were not different significantly (P > 0.05). In the control group, CD62-P, antifibrinogen and annexin-V levels increased significantly after ADP activation (P<0.05, P<0.05, P<0.01, respectively). In hyperlipidemic subjects, annexin-V expression increased significantly after activation (P<0.01), whereas expression of GpIIb/IIIa, CD62-P and antifibrinogen remained unchanged (P>0.05). The levels of total cholesterol (T-CHO), low density lipoprotein cholesterol (LDL-C), serum fibrinogen (S-FGN) and high density lipoprotein cholesterol (HDL-C) in patients were found to be correlated with platelet CD62-P, antifibrinogen, annexin-V, mono-PLA and MDA. CONCLUSIONS: In conclusion, it seems that in hyperlipidemia, some platelets are in an activated state in circulation, and that increased lipid peroxidation, early apoptosis, platelet-leukocytes aggregate formation and platelet aggregation altogether accompany this process.     

The headache triggered with ingestion of hot and soft fizzy drinks: similarity with ice cream headache

Ice cream headache is more frequent in migraineurs. This is probably due to the specific interactions between neural and vascular systems in migraine patients. Two patients suffering from ice cream headache reported us that a similar headache occurred during migraine attacks with various stimuli such as ingesting hot and fizzy drinks. In addition to the pace of ingestion and temperature of the material, central sensitization may also have a role in the occurrence of this pain. We think that various factors play role in this neuro-vascular interaction. Accepting the ice cream headache as a prototype of this neuro-vascular interaction could provide path to new concepts.     

Gut Permeability and Intestinal Mucins,Invertase, and Peroxidase in Control and Diabetes-Prone BB Rats Fed Either a Protective or a Diabetogenic Diet

This study deals with the enteropathy recently identified in diabetes-prone BB rats (BBdp). Diabetes-resistant BB rats (BBc) and BBdp rats were fed from days 32–39 onward either a protective diabetes-retardant hydrolyzed casein diet (HC) or a plant-based diabetogenic (NTP) diet. The NTP diet decreased body weight and plasma insulin in BBc and BBdp rats. The BBdp rats displayed low intestinal invertase and increased intestinal peroxidase activity. In the BBdp rats fed the HC diet, the mucin content 30–35 cm below the pylorus was higher and the gut permeability lower than in the other three rat groups. There was a significant inverse correlation between gut permeability and the insulinogenic index in the BBdp rats fed the HC or NTP diet. Thus, in BBdp rats, the HC diet somehow prevents the increase in gut permeability and the decrease in the insulinogenic index otherwise found in some of these diabetes-prone animals.     

Brain magnetic resonance imaging in tyrosinemia

A 3.5-year-old girl with tyrosinemia is reported. A computed tomography scan of the abdomen revealed multiple hepatic nodules. Brain magnetic resonance imaging revealed bilateral high-signal changes confined to the globus pallidus on T2-weighted images. Globus pallidus lesions likely represented neuropathologic changes such as astocytosis, delayed myelination, and status spongiosus (myelin splitting and vacuolation).     

An infant with pentalogy of Cantrell and limb defects diagnosed prenatally

We present a case of pentalogy of Cantrell which was diagnosed prenatally on routine ultrasound examination. There were several associated limb defects. We discuss the differential diagnosis and conclude that our case probably had a variant form of this syndrome.     

Neurocognitive functions after aortic arch repair with right brachial artery perfusion

Background

Satisfactory neurologic outcome following aortic arch repair through right brachial artery perfusion is well established. However, how neurocognitive functions are affected following selective cerebral perfusion, still needs to be elucidated.

Methods

In a period between April 2002 and March 2003, 22 patients (19 male, 3 female, with a mean age of 46.8 ± 12; range: 26 to 70 years old), underwent aortic arch repair using right brachial artery low flow (8 to 10 mL · kg⁻¹ · min⁻¹) selective antegrade cerebral perfusion under moderate hypothermia (26°C). There were 6 Stanford type-A dissections and 16 ascending aortic aneurysms. All patients were evaluated preoperatively and postoperatively (at seventh day and second month) for neurocognitive functions.

Results

There was no operative mortality. The average cardiopulmonary bypass time was 115.0 ± 24.2 minutes and the average antegrade cerebral perfusion time was 29.8 ± 7.1 minutes (19 to 38 minutes). No major neurologic deficit was observed in the postoperative period. In terms of neurocognitive test results, between the preoperative and postoperative assessments for both hemispheric cognitive functions no deterioration was detected.

Conclusions

The low-flow selective antegrade cerebral perfusion technique through the right brachial artery may safely be used for the great majority of patients undergoing aortic arch repair without causing deteriorations in neurocognitive functions.     

Emery-Dreiffus muscular dystrophy: MR imaging and spectroscopy in the brain and skeletal muscle

Emery-Dreifuss muscular dystrophy is a rare disorder characterized by childhood onset of contractures, humeroperoneal muscle atrophy, and cardiac conduction abnormalities. This report presents the cases of two brothers with this dystrophy in whom bilateral hypomyelination of the deep periatrial white matter was noted. In the hypomyelinated regions, a prominent peak centered at 1.5 parts per million was present on short-TE MR spectra likely representing prominence of proteolipids in the macromolecular region. Major peaks (N-acetyl-aspartate, creatine, choline, and myoinositol) were normal. With respect to muscle changes, atrophy of the medial head of the gastrocnemius muscle was noted at MR imaging, and phosphorus spectroscopy of this muscle revealed decreased phosphocreatine and inorganic phosphate peaks.