Simultaneous operative repair of multilevel lower extremity occlusive disease

Sixty-two patients (39 men (63%), 23 women (27%), mean age 68 years) with multilevel lower extremity arterial occlusive disease underwent simultaneous inflow and outflow operative arterial repair consisting of aortofemoral bypass in 22 (35%), axillofemoral bypass in 17 (28%), femorofemoral bypass in 15 (24%), iliac endarterectomy in 7 (11%), and unilateral aortoiliac bypass in 1 (2%), combined with 69 outflow procedures (unilateral in 55 patients, 89%), including above-knee femoropopliteal in 12 (17%), below-knee femoropopliteal in 35 (51%), femoroinfrapopliteal in 20 (29%), popliteal tibial in 1 (1%), and femoropedal bypass in 1 (1%). Multiple criteria were used to identify patients with multilevel disease likely to benefit from multilevel procedures. The operations were performed by two operating teams in a median time of 240 minutes. Prosthetic grafts were used for eight (13%) distal bypasses, the remainder were autogenous vein. There was one operative death (1.8%). The mortality rate, morbidity rate, and operative time were not significantly different from a group of patients who underwent concurrent, isolated inflow operations (aortofemoral, axillobifemoral, femorofemoral bypass or iliac endarterectomy). Mean follow-up was 14.9 months (range, 0 to 120). The life-table primary patency for the inflow procedures was 92.6% at 24 months, the outflow was 94.9% at 24 months. Cumulative limb salvage was 90.9% at 48-month follow-up. All patients with claudication were relieved of their symptoms. We conclude that complete correction of multilevel disease can be accomplished with operative time, morbidity rate, and patency equal to that of single level repair. Multilevel procedures provide complete relief of symptoms in a higher percentage of patients than has been reported after single level repair.     

Twenty-four hour esophageal pH monitoring by telemetry. Cost-effective use in outpatients

Of 366 cases of portal hypertension in adult patients referred for evaluation and management in the past 15 years, the cause was not related to cirrhosis or hemachromatosis in 41. No specific cause was demonstrated for portal hypertension in four cases, which were excluded from further evaluation. Of the remaining 37 patients, 26 had a presinusoidal block characterized primarily by bleeding from esophagogastric varices, and 9 had a postsinusoidal block characterized by the rapid development of intractable ascites. In two cases an arteriovenous fistula was the cause of portal hypertension. Treatment was operative or nonoperative depending on the nature and prognosis of the basic disease. The various approaches to therapy include shunting procedures for the control of ascites or esophagogastric varices, the use of a type of portal-azygous disconnection and a direct approach to a valve or a fistula. In the absence of a rapidly fatal primary disease, portal hypertension is not a threatening problem and may be controlled with minimal mortality by appropriate surgical management.     

Effect of exercise on hemodynamic conditions in the abdominal aorta

PURPOSE: The beneficial effect of exercise in the retardation of the progression of cardiovascular disease is hypothesized to be caused, at least in part, by the elimination of adverse hemodynamic conditions, including flow recirculation and low wall shear stress. In vitro and in vivo investigations have provided qualitative and limited quantitative information on flow patterns in the abdominal aorta and on the effect of exercise on the elimination of adverse hemodynamic conditions. We used computational fluid mechanics methods to examine the effects of simulated exercise on hemodynamic conditions in an idealized model of the human abdominal aorta. METHODS: A three-dimensional computer model of a healthy human abdominal aorta was created to simulate pulsatile aortic blood flow under conditions of rest and graded exercise. Flow velocity patterns and wall shear stress were computed in the lesion-prone infrarenal aorta, and the effects of exercise were determined. RESULTS: A recirculation zone was observed to form along the posterior wall of the aorta immediately distal to the renal vessels under resting conditions. Low time-averaged wall shear stress was present in this location, along the posterior wall opposite the superior mesenteric artery and along the anterior wall between the superior and inferior mesenteric arteries. Shear stress temporal oscillations, as measured with an oscillatory shear index, were elevated in these regions. Under simulated light exercise conditions, a region of low wall shear stress and high oscillatory shear index remained along the posterior wall immediately distal to the renal arteries. Under simulated moderate exercise conditions, all the regions of low wall shear stress and high oscillatory shear index were eliminated. CONCLUSION: This numeric investigation provided detailed quantitative data on the effect of exercise on hemodynamic conditions in the abdominal aorta. Our results indicated that moderate levels of lower limb exercise are necessary to eliminate the flow reversal and regions of low wall shear stress in the abdominal aorta that exist under resting conditions. The lack of flow reversal and increased wall shear stress during exercise suggest a mechanism by which exercise may promote arterial health, namely with the elimination of adverse hemodynamic conditions.     

Association between left ventricular mass index and cardiac function in pediatric dialysis patients

Background  

Left ventricular mass index (LVMI) is a surrogate of left ventricular hypertrophy and a predictor of cardiac morbidity and mortality in adults with hypertension. LVMI has not been linked to cardiovascular endpoints in children. The aim of this study was to identify an association between elevated LVMI and echocardiographic markers of systolic and diastolic function.     

Cardiovascular effects at multi-detector row CT colonography compared with those at conventional endoscopy of the colon

PURPOSE: To compare the cardiovascular effects of computed tomographic (CT) colonography and conventional endoscopy in a group of patients undergoing both procedures. MATERIALS AND METHODS: A total of 144 patients underwent CT colonography followed by flexible sigmoidoscopy (40 patients) or colonoscopy (104 patients). Pulse, blood pressure, and oxygen saturation were measured before, during, and after the procedures. Forty patients also underwent continuous Holter electrocardiographic (ECG) monitoring. Periprocedural pain was assessed by using a handheld counting device. Outcome variables were assessed by using a combination of paired t testing and multilevel linear regression. RESULTS: When a spasmolytic was not used, CT colonography was associated with only a small increase in oxygen saturation (P =.03), while use of a spasmolytic caused an increase in pulse (mean increase, 19.9 beats per minute; P <.001) and diastolic blood pressure (mean increase, 5 mm Hg; P <.001). Compared with that at CT, oxygen saturation decreased significantly during and after colonoscopy and sigmoidoscopy (mean decrease after colonoscopy with sedation, 1.0%; P <.001). Systolic and diastolic blood pressure also decreased during and after colonoscopy (mean systolic decrease after colonoscopy with sedation, 16.6 mm Hg, P <.001; mean diastolic decrease after colonoscopy with sedation, 7.5 mm Hg, P <.001). Patients were 30.3 times more likely to develop bradycardia after endoscopy (95% CI: 2.65, 346; P =.006). Ventricular couplets were significantly higher at endoscopy than at CT in patients with a history of cardiac disease (odds ratio: 72.5 and 95% CI: 4.56, 1,153 at CT vs odds ratio: 14.6 and 95% CI: 0.96, 222 at endoscopy; P =.002). Patients were 1.89 times more likely to register pain during colonoscopy than during CT (95% CI: 1.06, 3.38; P =.03). CONCLUSION: CT colonography had no significant cardiovascular effect other than spasmolytic-induced tachycardia. Endoscopy-and colonoscopy in particular-causes cardiovascular effects that are largely related to sedation. CT colonography is less painful than colonoscopy and is comparable to flexible sigmoidoscopy.     

Carotid surgery following previous carotid endarterectomy is safe and effective

With the perceived high risk of repeat carotid surgery, carotid angioplasty and stenting have been advocated recently as the preferred treatment of recurrent carotid disease following carotid endarterectomy. An experience with the operative treatment of recurrent carotid disease to document the risks and benefits of this procedure is presented. A review of a prospectively acquired vascular registry over a 10-year period (Jan. 1990-Jan. 2000) was undertaken to identify patients undergoing repeat carotid surgery following previous carotid endarterectomy. All patients were treated with repeat carotid endarterectomy, carotid interposition graft, or subclavian-carotid bypass. The perioperative stroke and death rate, operative complications, life-table freedom from stroke, and rates of recurrent stenosis were documented. During the study period 56 patients underwent repeat carotid surgery, comprising 6% of all carotid operations during this period. The indication for operation was symptomatic disease recurrence in 41 cases (73%) and asymptomatic recurrent stenosis >/=80% in 15 cases (27%). The average interval from the prior carotid endarterectomy to the repeat operation was 78 months (range 3 weeks-297 months). The operations performed included repeat carotid endarterectomy with patch angioplasty in 31 cases (55%), interposition grafts in 19 cases (34%), and subclavian-carotid bypass in 6 cases (11%). There were three perioperative strokes with one resulting in death for a perioperative stroke and death rate of 5.4%. One minor transient cranial nerve (CN IX) injury occurred. Mean follow-up was 29 months (range, 1-116 months). Life-table freedom from stroke was 95% at 1 year and 90% at 5 years. Recurrent stenosis (>/=80%) developed in three patients (5.4%) during follow-up, including one internal carotid artery occlusion. Two patients (3.6%) underwent repeat surgery. Repeat surgery for recurrent cerebrovascular disease following carotid endarterectomy is safe and provides durable freedom from stroke. Most patients are candidates for repeat endarterectomy with patching, but interposition grafting is often required. These results strongly support the continued role of repeat carotid surgery in the treatment of recurrent carotid disease.     

Color Doppler Visualization of Intramyocardial Coronary Arteries Using a New Echo System: Effect of Contrast Enhancement and Vasodilation

Utilizing a new echocardiographic system, intramyocardial coronary arteries could be demonstrated by color Doppler in a small number of open chest animals. Both intravenous and intracoronary injections of a contrast agent (Levovist) resulted in significant enhancement of color flow signals with an increase in the length, width, and the number of these vessels. Similar results were obtained with intravenous infusion and direct intracoronary injections of a vasodilator (adenosine).     

Disease surveillance in recombining pathogens: multilocus genotypes identify sources of human Coccidioides infections

Molecular surveillance of pathogenic microbes works by genotyping isolates with DNA fingerprinting techniques and then using these genotypes to assign individuals to populations. Clonality is assumed in many fingerprinting studies, although this assumption has been shown to be false for many organisms. To accommodate recombining organisms into surveillance programs, methods using population allele frequencies in combination with individual multilocus genotypes are necessary. Here, we develop a statistical method appropriate for haploid recombining microbes that allows individuals to be assigned to populations. We illustrate the usefulness of this technique by inferring the source populations for Coccidioides isolates recovered from patients treated outside the endemic area of Coccidioides sp., the etiological agents of human coccidioidomycosis, but with a travel history including visits to one or more endemic areas.