Edward G. Shifrin

Angiographic and Duplex Grading of Internal Carotid Stenosis: Can We Overcome the Confusion?

The stroke risk reduction benefit of surgical intervention in carotid occlusive disease has been validated in multicenter trials for various angiographically defined lesion severity categories. The two divergent angiographic grading methods used for internal carotid artery stenosis in these trials have caused confusion in the clinical application of their recommendations. Moreover, while todays highly accurate carotid duplex scanning can obviate the need for preoperative angiography in many cases, the duplex criteria must be tailored to achieve sufficiently reliable results on which therapeutic decisions can be made. This review offers a clarification of the discrepancies between the angiographic grading techniques and how their measurements of percent stenosis correlate to the duplex criteria needed to support the treatment decision-making process for carotid obliterative disease.

Renal Vein Occlusion: A Review

PURPOSE The different etiologies of renal occlusion are reviewed. A special category, division of the left renal vein in abdominal aortic surgery, is also discussed in the review. MATERIALS AND METHODS The various diagnostic modalities used in cases of renal vein occlusion include excretory urography, ultrasound, nuclear scan, angiography, venography, computerized tomography and magnetic resonance imaging. The main goals of therapy in this condition should be conserve renal parenchyma and to protect renal function. RESULTS The principal mode of treatment is medical and includes correction fluid and eletrocyte imbalance, dialysis, antihypertensive drugs, anticoagulation and in certain cases thrombolysis. CONCLUSIONS Renal vein occlusion in adults is usually a result of the vein thrombosis which is frequently associated with the nephrotic syndrome. The anatomy of renal vascularization is of primary importance in understanding its pathophysiological responses and the clinical and diagnostic presentation of patients with this condition. The reaction of the kidney to its vein occlusion is determined by the balance between the acuteness of the disease, extent of the development of collateral circulation, involvement of 1 or both kidneys and the origin of the underlying disease. Renal vein occlusion is generally a complication of some other condition but may also be a primary disease.

Optimal dosing as a necessary condition for the efficacy of hyperbaric oxygen therapy in acute ischemic stroke: A critical review

Abstract The effectiveness of hyperbaric oxygen therapy (HBOT) in clinical and experimental acute ischemic stroke (AIS) has been controversial for many years. However, in the literature, no data was found on the dose/effect of HBOT in patients with AIS. We analyzed retrospectively the published data of clinical studies performed in different hyperbaric centers (a total of 265 patients). The dose of HBOT (DHBOT) was calculated considering the product intrabarochamber pO2 (ATA), the duration of a single HBOT exposure (hours), and the number of HBOT treatments. Efficacy of HBOT (EfHBOT) data regarding the number of patients who showed significant clinical improvement of their neurologic status in the course of the treatment HBOT (the percentage of the total number of patients). The level of EfHBOT in each study was compared with a corresponding value of D HBOT. A comparison of the data shows a pronounced tendency H for higher values of EfHBOT as the level of the average values of the total DHBOT increases. The coefficient of correlation between these parameters appears to be fairly high (r = 0.92). The maximum possible value of EfHBOT is 100%, which corresponded to the average values of DHBOT at a level of no less than 30 agreed units. The examined data suggest that applying optimal total DHBOT may provide a maximum possible EfHBOT in treating patients with AIS.

Revascularisation for a Poorly Functioning Solitary Kidney

Renovascular disease in a solitary kidney is a difficult and challenging problem. In six patients, with a mean age of 62 years, revascularisation was undertaken. In four of them, one to three attempts at PTA were made before the operation but all were unsuccessful. The preoperative mean serum creatine (Cr) was 3.52 mg% (range 2.5-5.5). The stenoses were caused by atherosclerosis in five cases and fibromuscular dysplasia (FMD) in one. Two methods of revascularisation were used: aortorenal bypass with saphenous vein (three patients) or PTFE (two patients), and transaortic renal endarterectomy with a venous patch (one patient). One patient with an aortic aneurysm underwent simultaneous aortic repair with a PTFE graft. There was no mortality or major complications in our series and no patient suffered acute tubular necrosis (ATN) after surgery. The mean follow-up period was 51 months (15-84 months). Postoperative Cr and blood pressure improved in all patients. Four patients no longer required any medication and the other two only needed reduced doses of antihypertensive drugs. Based on our experience of patients with poor single kidney function, we do not recommend PTA in this specific group of patients and suggest an aggressive surgical approach, which can effectively improve solitary kidney function, thus eliminating further haemodialysis.

Acute Respiratory Distress Syndrome in Patients after Blunt Thoracic Trauma: The Influence of Hyperbaric Oxygen Therapy

The rate of mortality from acute respiratory distress syndrome (ARDS) has reportedly reached as high as 50–75%.1−3 The risk of ARDS development increases after severe blunt thoracic trauma (BTT) because of a higher likelihood for lung contusion4 and acute depression of cardiac function.5, 6 Monitoring of oxygen transport in patients with ARDS has shown that oxygen delivery and consumption were significantly higher in the survivors compared to nonsurvivors.7 This suggests that maintenance of oxygen delivery at optimal levels can potentially enable the reversal of ARDS.8 In cases of severe BTT, these oxygen transport variables may be induced by early cardiorespiratory dysfunction6, 9 which requires inotropic support.6, 8, 10 On the strength of these data, it is reasonable to conclude that the prevention and correction of oxygen deficiency are basic to intensive care during ARDS.