Use of transcranial Doppler sonography and acetazolamide test to demonstrate changes in cerebrovascular reserve capacity following carotid endarterectomy

OBJECTIVES

To assess the effect of carotid endarterectomy on cerebrovascular reserve capacity.

METHODS

Cerebral blood flow velocity (CBFV) and cerebrovascular reserve capacity (CVRC) were measured by transcranial Doppler sonography (TCD) and acetazolamide test in 40 patients who underwent uncomplicated unilateral carotid endarterectomy (CEA). Indication for operation was limited to stenoses > 70% as documented by angiography and/or Duplex scanning. The TCD studies were carried out 6 days (range 1-14 days) before and 8 days (range 5-12 days) after endarterectomy.

RESULTS

Before endarterectomy, resting CBFV values and CVRC in the 40 patients were significantly different between the operated (51 +/- 19 cm/s; 20 +/- 16%) and the non-operated (60 +/- 19 cm/s; 34 +/- 24%) hemisphere (p < 0.05;p < 0.01). After CEA the overall increase of resting CBFV of the operated side was highly significant with preoperative CBFV values of 51 +/- 19cm/s and postoperative values of 62 +/- 15 cm/s (p < 0.01). Cerebrovascular reserve capacity after operation was increased on both sides significantly (non-operated side: from 34 +/- 24% to 43 +/- 19%, p < 0.05; operated side: from 20 +/- 16% to 51 +/- 18%, p < 0.001), and the preoperative asymmetry was no longer present.

CONCLUSIONS

CEA has a beneficial effect on the cerebral circulation in most patients, even those who presented with asymptomatic carotid artery stenosis. Since CVRC has been assessed in the early postoperative period, our findings also suggest that cerebral vascular adaption occurs within 2 weeks after CEA.

Characterization of edema by diffusion-weighted imaging in experimental traumatic brain injury

The objective of this study was to use diffusion-weighted magnetic resonance imaging (DWI) to help detect the type of edema that develops after experimental trauma and trauma coupled with hypotension and hypoxia (THH). Reduction in the apparent diffusion coefficients (ADCs) is thought to represent cytotoxic edema. In a preliminary series of experiments, the infusion edema model and middle cerebral artery occlusion models were used to confirm the direction of ADC change in response to purely extracellular and cytotoxic edema, respectively. The ADCs increased (p<0.05) in the case of extracellular edema and decreased (p<0.001) in cytotoxic edema. Following these initial experiments, a new impact acceleration model was used to induce traumatic brain injury. Thirty-six adult Sprague-Dawley rats were separated into four groups; sham, trauma alone, hypoxia and hypotension (HH), and THH. Following trauma, a 30-minute insult of hypoxia (PaO2 of 40 mm Hg) and hypotension (mean arterial blood pressure (MABP) of 30 mm Hg) were imposed and the animals were resuscitated. The DWI was carried out at four 1-hour intervals postinjury, and MABP, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and cerebral blood flow (CBF) were monitored. The ADCs in the control and HH groups remained unchanged. The ADCs in the THH group rapidly decreased from a control level of 0.68 +/- 0.05 x 10(-3) mm2/second to 0.37 +/- 0.09 x 10(-3) mm2/second by 3 hours posttrauma (p < 0.001). In this group, the decreased CBF and CPP during secondary insult remained low despite resuscitation, with the ICP increasing to 56 +/- 7 mm Hg by 3 hours. In the trauma alone group, the rise in ICP reached a maximum value (28 +/- 3 mm Hg) at 30 minutes with a significant and sustained increase in CBF despite a gradual decrease in CPP. The ADCs in this group were not significantly reduced. The data lead the authors to suggest that the rise in ICP following severe trauma coupled with secondary insult in this model is predominately caused by cytotoxic edema and that ischemia plays a major role in the development of brain edema after head injury.

[Bronchiolitis obliterans organizing pneumonia: survey based on two cases]

Authors offer a survey about an aspect forming a clinical entity called bronchiolitis obliterans organizing pneumonia, by two of their patients' presentation. In Case 1 the process manifested in form of a disseminated, small spotted, diffuse shadow, causing serious resting hypoxia. Diagnosis was supported by histological examination of a substance obtained by small surgical thoracotomy. Five months' therapy of Imuran and altogether 15 months' therapy of Prednisolon resulted in recovery. Second patient's symptoms and the shadow representated in the left upper lung field on chest X-ray, proposed the probability of a tumour. The lesion removed surgically, together with the left upper lobe, proved to be the clinical appearance that constitutes histologically the subject of this paper. Surgery alone resulted in definitive recovery. Disease can be proved on the basis of histological picture and it's important to sunder it primarily from bronchiolitis obliterans as well as from other interstitial pulmonary diseases.

Our policy in diagnosis and treatment of hydrocephalus

The authors present the policy they have worked out for hydrocephalus patients with special reference to the pressure measurement and test methods and to rCBF, SPECT and transcranial Doppler sonography (TDC) studies. For diagnosis, the protocol proposed by Gjerris and Borgesen was followed in 75 cases: besides other methods (CT, radionuclide cisternography, MRI) the intracranial pressure waves routinely recorded and analyzed by means of ventricular catheters for 24 h. The patients were roughly divided into groups in terms of diagnosis, baseline pressure, compliance, results of infusion tests and of surgery. In 13 patients the investigations were supplemented by rCBF SPECT and in 42 patients by TCD studies before and after CSF shunting or withdrawal to analyze the acute effects on cerebral circulation. Clinical follow-up shows that need for shunting was indicated fairly well by the common results of baseline ICP, compliance and infusion loading. The rCBF SPECT studies revealed a significant increase of the cerebral perfusion at the basal ganglia after shunting while, on the basis of CBF velocity changes three types of vasoregulatory response could be defined with TCD. In our hands, monitoring of the pressure and craniospinal capacity has proved to be a valuable aid in decisions on surgery; however, for a more precise (and beneficial) appreciation of whether surgery is indicated the vasoregulatory responses should also be taken into account in future.

Evaluation of cerebral vasoreactivity by SPECT and transcranial Doppler sonography using the acetazolamide test

rCBF SPECT with 99mTc-HMPAO was performed prospectively in 29 patients (3 controls and 26 stroke patients) as well as TCD studies in 20 patients (3 controls and 17 stroke patients) before and after 1 g i.v. acetazolamide. The sensitivity of rCBF SPECT increased from 62% to 77% after acetazolamide provocation in stroke patients. In patients with a reversible neurological deficit, the sensitivity under resting conditions was 50% which increased to 71%, while in cases with a permanent deficit it increased from 75% to 83%. In the evaluation of the cerebrovascular reserve capacity the results of rCBF SPECT and TCD coincided in 91% of the hemispheres. The correlation was statistically significant.

[Primary malignant melanoma of the lung and lower respiratory tract]

After detailed analysis of the international special literature, the authors found--together with their own two patients--only 18 cases, considered primer malignant melanoma of the lower respiratory tract and/or lung. Of the accepted criteria, they dispute the obduction's absolute evidentiary role, because among primer patients there are the most who survives, even a decade. In seven cases tumour was located endobronchially and in one patient in the trachea. It was manifested endobronchially and on the dependent lung-areas, simultaneously in two patients and merely parenchymally, in eight. There was a successful resection in fourteen of 18 cases. Survival was influenced primarily by the operability depending on distension of the tumour. Besides procedures forming opinions, bronchoscopy and histological examinations of bioptatum gained this way play a greater role than usual in determining the tumour's primarity, localisation, operability and type of surgery, respectively. Namely, only operated patients can rely on a long survival.

[Clinical significance of lumbosacral transitional vertebrae (Bertolotti syndrome)]

500 lumbosacral plain x-ray injured patients and 1000 myelography of patients suffering from low back pain and nerve root sign were reviewed to evaluate the rate of transitional lumbosacral vertebra. This anomaly appeared in 4.6% in the normal population. The rate of the transitional vertebra in patients with nerve root syndrome was double (8.4%) whereas that with lumbar disc herniation four time as many as in the normal population. The data demonstrate that the asymmetrical anomalies have more clinical significance. The authors consider, that the role of the transitional vertebra is twofold: it can be consider primary in low back and sciatic pain, but in the formation of lumbar disc herniation is secondary. They find the analysis of the lumbosacral plain x-ray is necessary even in cases with CT and MRI.

[Aspiration of barium contrast medium and its prevention]

The authors have been noted aspiration bronchograms associated with barium-filling study of the upper gastrointestinal tract in 58 patients involving basal medial, anterior, lateral and posterior segments of the lower pulmonary lobes, mammary segment of the middle lobe, moreover inferior lingula. In 75.9% of patients (44 cases) the barium meal got to bilateral basal medial, anterior and lateral segments. The 34 men and 24 women had a mean age of 69 years (range, 29-88 years). The aspiration was found 3.8-times more frequent after completion of patient's 50th year than before it observed. A transient tertiary mobility disorder of the esophagus, extrasystoles and tendency for collapse were on barium-filling of bronchi. In 15 of the 18 patients the Valsalva's maneuver proved a pharyngomyodystonia. Carrying out of endoradiography depended on function of the lateral pharyngeal wall. The bronchi with physiological saline following aspiration of the contrast medium within 30 minutes were lavaged.

[Cardiorespiratory and electrolytic changes in status asthmaticus after intravenous administration of magnesium sulfate]

The authors studied cardiorespiratory effects of MgSO4 infusion in 30 randomized patients with status asthmaticus. They found, that after having the drug administered, values of VC, FEV1, FIV1, PaO2 and pH increased, the respiratory and heart rate, diastolic blood pressure reduced. Other ventilation, blood gas and ECG parameters were unchanged. Among the electrolytes, serum Ca2+ level has reduced, both plasma and intracellular Mg2+ concentrations increased. It is apparent from the results, that broncholytical ability of MgSO4 given in therapeutical dose i.v. does not reach the level of beta-stimulating agents. However, this completed with the cardioprotective, sedative effect as well as more advantageous ion-distribution, influences favourably the asthmatic dyspnoea.

[The effect of carotid endarterectomy on the reserve capacity of cerebral blood flow velocity]

Cerebral blood flow velocity was measured by transcranial Doppler sonography at rest and during cerebral vasodilatation evoked with acetazolamide in 14 patients before and after carotid endarterectomy. Before surgery the vasoreactivity in the affected middle cerebral artery territories was reduced and abnormal (asymptomatic side: 35.9 +/- 25.6% [mean +/- SD; n = 14]; symptomatic side: 25.6 +/- 10.7%), but the difference between the two hemispheres was not significant however, vasoreactivity was normalized 5 days after surgery (asymptomatic side: 46.9 +/- 22.3% symptomatic side: 58.9 +/- 23%) (p < 0.001). The increase in cerebral reserve capacity and changes in Gosling's index of pulsatility correlated significantly in both hemispheres (p < 0.02). This findings indicate an improved perfusion reserve on the fifth day following carotid endarterectomy in patients with an internal carotid artery diameter reduction of at least 70%.

Lack of short-term autoregulation in the cochlear microcirculation in guinea pigs

To determine the relationship between the dynamics of mean arterial blood pressure (MABP) elevation and possible changes in the cochlear microcirculation the cochlear blood flow (CBF) was measured in guinea pigs by a laser Doppler method. The MABP was elevated at rates ranging from 0.02 mmHg/s to 4 mmHg/s by intravenous infusions of norepinephrine or epinephrine in various concentrations. A fall in MABP was induced by exsanguination of the animals. The purpose of the experiments was to record the time of onset and course of an expected autoregulation in the cochlea in response to slow or rapid changes in MABP. The data suggest that there is no short-term autoregulation in the cochlear microcirculation reflecting the increase of the MABP, but a slight compensation occurs when the MABP declines. These latter changes could be attributed to the high CO2 sensitivity of the cochlear blood vessels.

Significance of the rate of systemic change in blood pressure on the short-term autoregulatory response in normotensive and spontaneously hypertensive rats

Cerebral autoregulation, the physiological regulatory mechanism that maintains a constant cerebral blood flow (CBF) over wide ranges of arterial blood pressure, was investigated in normotensive and spontaneously hypertensive rats by means of laser-Doppler flowmetry. Systemic arterial hypertension was produced at rates ranging from 0.02 mm Hg/second to 11 mm Hg/second by constant infusion of epinephrine and norepinephrine. Systemic arterial hypotension was produced at rates ranging from -0.03 mm Hg/second to -12 mm Hg/second, either by bleeding the animals into a reservoir or by compressing the abdomen. In those cases with a low rate of change in systemic arterial blood pressure (SABP), the measurements lasted for 5 +/- 2 minutes, and in those with a high rate of change in SABP, measurements lasted for 40 +/- 30 seconds. The purpose was to record the time of onset and course of autoregulation in the basal ganglia in response to slow or rapid changes in SABP. CBF in the basal gray matter remained at baseline values (i.e., autoregulation was functioning) if the rate of increase of SABP did not exceed a critical value (0.10 mm Hg/second in the normotensive rats; 0.35 mm Hg/second in the spontaneously hypertensive rats). When hypertension was produced at faster rates, CBF followed arterial blood pressure passively, and no autoregulatory response was observed for 2 +/- 1 minutes. Hypotension did not change the baseline CBF when it was not produced at a rate faster than -0.4 mm Hg/second in normotensive rats and -0.15 mm Hg/second in spontaneously hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[Bronchoalveolar lavage in the confirmation of pulmonary involvement in chronic lymphoid leukemia]

The authors made bronchoalveolar lavage (BAL) for explaining the origin of diffuse bilateral lung--infiltration in patients with chronic lymphoid leukaemia. On the base of lavage-fluid, the lung damage may be caused by leukaemic infiltration. The lesion has not changed by antibiotic therapy, but was radiologically cured after giving corticoids. The authors have not read about approaching chronic lymphoid leukaemic pulmonary infiltration by BAL. They call attention to the etiologic clarification of lung organs' complications in haematological aspects and outstanding role of BAL as a non-invasive method.

[The value of acetazolamide provocation combined with blood flow tests in the diagnosis of ischemic cerebrovascular diseases]

In 28 (3 normal, 11 TIA, 14 completed stroke) patients 99mTc-HMPAO rCBF SPECT studies were performed at rest and after acetazolamide administration. For the investigations, a one-day protocol (the stress study directly followed the rest investigation) was used. The reconstructed and normalized slices were evaluated visually and semiquantitatively with a side difference analysis method. In the group of TIA patients, the abnormal results of the rCBF investigations increased from 55% to 82% after acetazolamide provocation. The corresponding results in the completed stroke group were 80% and 87%. After acetazolamide stimulation, hypoperfusion appeared or become more pronounced in the majority of the TIA group patients in contrast with the completed stroke patients with an unchanged or decreased perfusion abnormality. The semiquantitative evaluation method was mostly effective in the TIA group, where predominantly a one-sided cerebrovascular disorder was suspected. It was concluded that the 99mTc-HMPAO studies allow demonstration of the acetazolamide-induced cerebral perfusion alterations, and this method can be useful in the diagnosis and management of cerebrovascular disorders.

[Determination of the cerebrovascular reserve capacity by using acetazolamide as well as transcranial Doppler and SPECT tests]

The aim of this study was the development of a simple bedside test to assess cerebrovascular reserve capacity using transcranial Doppler sonography. We tried to validate the increase in blood flow velocity as cerebrovascular reserve capacity in 20 (3 normal, 7 TIA, 10 completed stroke) patients. They were studied using transcranial Doppler sonography and rCBF SPECT before and after injection of 1 g acetazolamide. Their increases in blood flow velocity and changes in cerebral blood flow correlated significantly in the symptomatic hemispheres (p less than 0.001). Blood flow velocity between the two hemispheres (symptomatic and asymptomatic) was not significantly different at rest. We offer these simple and reliable methods in clinical studies to clarify the frequency of ischemic stroke of hemodynamic origin.

[Bronchoscopic appearance of the bronchial mucosa in pulmonary venous hypertension]

The authors studied the bronchoscopic appearance of bronchial mucosa's vessel contour in pulmonary venous hypertension in 20 patients with mitral stenosis and in 20 with cardiomyopathy and/or aortic vitium. The submucous venous congestion was scored on the base of its extent and severity according to Ohmichi. They have observed a linear relation between the PPA (wedge) and PPA values in patients with mitral stenosis and the total scores indicatory of submucous venous congestion. The mean total scores of patients with mitral stenosis as well as cardiomyopathic patients showing volume-loading of the pulmonary circuit and/or aortic vitium differed to the benefit of the former. Mucosa's vessel contour of grade 3 was found in 12 patients with mitral stenosis and only in 4 cases of cardiomyopathy and/or aortic vitium, so that is more characteristic of mitral stenosis. In spite of this, condition of patients with cardiomyopathy and/or aortic vitium are considered more severe on the base of NYHA values. Taking both patient populations into consideration relation between NYHA-phase and the degree of total scores could not have been proved. Venous congestion on lower part of the left main bronchus was observed in every patient. Appearance of congestive bronchial mucosa has not occurred in pure precapillary pulmonary hypertension.

Measurements of regional cerebral blood flow and blood flow velocity in experimental intracranial hypertension: infusion via the cisterna magna in rabbits

Cerebral blood flow velocity, as measured in the intracranial segment of the internal carotid artery by transcranial Doppler sonography via the transorbital route, and regional cerebral blood flow and volume in corresponding cortical areas, as measured by the hydrogen clearance technique, were recorded for eight New Zealand White rabbits subjected to infusion via the cisterna magna to elevate intracranial pressure. In the lower range of autoregulation, that is, at perfusion pressures between 80 and 40 mm Hg and even lower, the changes in cerebral blood flow velocity and cerebral blood flow showed a strong correlation (0.86) under conditions of standard pCO2 (PaCO2 = 35 +/- 2 mm Hg). Autoregulation was exhausted at 40 mm Hg, and the cerebrovascular resistance was minimal. Below this perfusion pressure, the cerebral blood flow and volume dropped sharply, whereas the cerebrovascular resistance gradually increased, indicating that, despite the maximally dilated resistance vessels, intracranial hypertension causes vascular resistance to increase, possibly via blocking of the venous outflow. Our results confirmed that noninvasive and easily (even at bedside) applicable measurements of changes in cerebral blood flow velocity could be a substitute for the cumbersome and expensive isotope measurements of cerebral blood flow in patients with intracranial hypertension.

Transbronchial mediastinal cystography

This article demonstrates a new method applied to two patients suffering from a subcarinal, mediastinal cyst, which, however, remained undetected by routine roentgenographic tests. In the first case, transbronchial needle aspiration was applied to remove the content of the cyst and injecting an x-ray contrast material (Endocistobil) for contrast roentgenography, whereas in the second patient the same x-ray contrast substance was injected by using an ultrathin catheter introduced through an opening which connected the cyst with the bronchial system. This method represents progress in the preoperative diagnosis of subcarinal mediastinal cysts.

Bronchial papillomas of various origins

There were five cases of solitary papillomas and three of chronic infectious papillomatosis induced by a foreign body, one caused by broncholithiasis. The five isolated papillomas had verrucous appearances. The common opinion, that the solitary papilloma is likely to be a pedunculary tumor, seems untrue. Squamous or cylindric epithelium covering the same tumor may vary from region to region. We believe that multiple polyps caused by inhalation of hot, burning, and corrosive gases are of inflammatory origin. Once the causative factor (eg, a late diagnosed foreign body) is removed, the inflammatory papillomatosis may resolve spontaneously. After the removal of a benign papilloma, recurrence is usually caused by lack of operative radicality rather than by malignancy. Laser technique and other coagulation methods make it possible to remove most tumors by performing bronchoscopy with only little risk. Papillomas showing the signs of atypia and peribronchial spreading require later surgery.