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Biomedical subjects

S Karacagil

Publications and source records attributed to S Karacagil.

At least 55 records · Page 3Linked to original sources
PubMed1998

2D inflow MR angiography in severe chronic leg ischemia.

PURPOSE: The aim of this study was to compare 2D inflow MR angiography (MRA) with selective X-ray angiography (XRA) in patients with severe chronic leg ischemia. MATERIAL AND METHODS: In a blinded prospective study, 2D inflow MRA and XRA were compared with regard to evaluation of the arteries distal to the knee in 24 patients (median age 72 years) with severe ischemia; 23 of them had either rest pain or tissue loss. Statistics were calculated with XRA as the reference method. RESULTS: The interpretations of 2D inflow MRA and XRA showed moderate agreement in the calf arteries but poor agreement in the foot arteries. Of the discrepancies, two-thirds were observer-related and only one-third method-related. Of all the comparable arteries, 9% showed method-related differences between the two methods. An assessment of MRA using only maximum intensity projections (MIP) resulted in 19% of findings being judged inconclusive whereas all the arteries could be classified when the cross-sectional images were studied on the viewing console. CONCLUSION: The agreement between MRA and XRA was good in the calf but questionable in the foot.

Adult↗
PubMed1997

Influence of twist on vein and PTFE graft hemodynamics: an ex vivo experimental study.

OBJECTIVE: In an ex vivo infusion model, the effect of different factors affecting the critical level of twist in vein and PTFE grafts was analysed. SETTING: University Hospital, Department of Surgery. EXPERIMENTAL DESIGN: Saline perfusion of grafts with various diameter and length under constant high (90 ml/min) and low (50 ml/min) flow rates against various peripheral resistance was performed. MEASURES: The pressure changes in the grafts were measured at increasing increments of twisting. RESULTS: The critical level of twist appears to be dependent on the diameter, length, stretching, status of peripheral resistance, amount of volume flow and the type of graft material, varying between 90 to more than 360 degrees. In vein grafts critical twisting appeared earlier with a decrease in diameter, shortening in length, high peripheral resistance, high flow rate and stretching. PTFE grafts especially with external spiral support were resistant to twist. CONCLUSIONS: These data suggest that the critical level of graft twist is dependent upon multiple factors and moderate or even high grade twist with especially externally supported PTFE grafts regardless of length and long mobilized vein grafts do not lead to hemodynamic changes. On the other hand total cessation of flow occurs at lower degrees of twist in stretched, short vein grafts.

Blood Vessel Prosthesis↗
PubMed1996

Secondary aortoenteric fistulae--changes from 1973 to 1993.

AIM: To investigate a series of patients with secondary aortoenteric fistulas and compare it with a previous series (1985-93 vs. 1973-84). DESIGN: Retrospective study of medical records. SETTING: Sixteen vascular surgical centers in Sweden. PATIENTS: Twenty-seven patients were identified making an overall incidence of 0.5% of all aortoiliac operations. Among aneurysm patients the incidence was significantly lower than in the previous series. One patient record could not be identified. Fourteen primary operations were for aortic aneurysm, 12 for occlusive disease and one was an aortorenal vein bypass. RESULTS: Symptoms of the fistula occurred after a median interval of 90 months which is significantly later than the previous series (32 months; p<0.05). The commonest presentation was bleeding followed by septis. The median diagnostic delay was 10.5 days, which was significantly shorter than in the previous series. Most fistulas involved the duodenum (88%). One patient died before surgery. The postoperative mortality was 28%, significantly lower than in the previous series (58%) (p<0.05). At the end of follow up (median 43 months) significantly more patients were alive than in the previous series (42% vs 18%) (p<0.05). CONCLUSION: Over a 21 year period there seems to have been a decrease in the frequency of secondary aortoenteric fistulas after aneurysm surgery, a longer interval before they occur, a shorter diagnostic delay, and a better survival.

Aorta, Abdominal↗
PubMed1996

Value of duplex scanning in evaluation of crural and foot arteries in limbs with severe lower limb ischaemia--a prospective comparison with angiography.

OBJECTIVES: To compare Duplex scanning with angiography for evaluation of crural and pedal arteries in limbs with lower limb ischaemia. DESIGN: The findings obtained during Duplex scanning and angiography were prospectively compared in a blinded manner. SETTING: Departments of Surgery, Diagnostic Radiology and Clinical Physiology, University Hospital. MATERIALS: Duplex scanning and selective angiography of femoropopliteal, crural and foot arteries were performed in 40 limbs (38 patients, 480 segments) with intermittent claudication (n = 6), rest pain (n = 13) and ulcer/gangrene (n = 19). Each arterial segment were graded into four categories: normal, < or = 50% diameter reduction, > 50% diameter reduction and occlusion. Pedal arteries were evaluated as patency or occlusion of dorsal pedal artery and plantar arch. CHIEF OUTCOME MEASURES: Accuracy (AC), sensitivity (SE), specificity (SP), positive predictive (PPV), negative predictive (NPV) and kappa values. MAIN RESULTS: The Duplex scanning of the tibioperoneal trunk, crural and pedal arteries had an accuracy of 80% (kappa = 0.6). The SE, SP, PPV and NPV values were 83%, 77%, 79% and 81%, respectively. The SP was relatively low for the peroneal artery (58%) compared to the others. CONCLUSIONS: The results demonstrate the feasibility and reliability of Duplex scanning in detecting crural and pedal artery lesions in lower limbs with severe ischaemia.

Adult↗
PubMed1996

Composite polytetrafluroethylene/vein bypass grafts: conventional distal vein segment or vein cuff?

OBJECTIVES: To determine the current status of PTFE vein composite grafts, we reviewed our experience with 205 composite reconstructions and compared the results of conventional distal vein segment to that of distal vein cuff. DESIGN: Retrospective review. SETTING: Department of Surgery, University Hospital. PATIENTS AND METHODS: The series included 85 women and 102 men with a median age of 70. The indications for surgery were claudication in 30, rest pain in 71 and ulcer/gangrene in 103. The site of the distal anastomosis was the popliteal artery in 111 and crural artery in 94. The graft consisted of a proximal PTFE graft anastomosed to a distal segment of reversed saphenous vein in 169 or to a modified distal Miller cuff in 36 operations after 1992. RESULTS: Cumulative life table primary patency rates for the whole series at 12, 24 and 36 months were 39%, 32% and 25% respectively. Limbs with good run-off demonstrated significantly better patency rates compared to limbs with poor run-off (55% and 17% at 12 months, 35% and 11% at 36 months, p = 0.04). The patency rate of femorocrural grafts with poor run-off was only 4% at 12 months. The overall limb salvage rates at 12 and 36 months were 63% and 55%, respectively. Similar results were obtained in limbs with distal reversed vein segment and distal vein cuff. CONCLUSION: The results of this study suggest that for infrainguinal bypass grafting where the saphenous vein is unavailable, a composite PTFE-vein graft might be an acceptable alternative in limbs with good run-off. Although not a randomised study, the results using a distal reversed vein segment of a cuff were similar.

Adult↗
PubMed1996

A modified technique of ultrasonic triplex scanning of the lower extremity arteries.

This study was undertaken to evaluate the utility of a modified technique of triplex scanning of the lower extremity arteries in 20 subjects without any clinical signs of arterial disease. The distal aorta and iliac arteries were examined with the subject in supine position and lying slightly on the opposite side. By moderate compression of the probe towards the psoas muscle and directing it over the iliac arteries with slight medial retraction of the abdomen, satisfactory visualization of the common and external arteries with 7.5 MHz high resolution imaging and a 5.6 MHz doppler probe were obtained in 56 of 80 segments (70%). In obese individuals it was necessary to use 5 MHz probe for satisfactory scanning of the aortic bifurcation and common iliac arteries. The distal superficial femoral, popliteal and tibioperoneal trunk segments were examined with the patient prone and the knee slightly flexed. Peak systolic, early diastolic reverse and late diastolic forward flow velocities were studied together with measurement of the arterial diemeters, which demonstrated wide variations. This study suggests that satisfactory scanning of the iliac and femoropopliteal arteries with the described technique can be achieved in the majority of subjects with a superficial high resolution probe. The combination of 7.5 MHz two-dimensional imaging with a 5.6 MHz pulsed wave Doppler probe offers optimal information of these arteries in nonobese individuals.

Adult↗
PubMed1996

Patterns of atherosclerotic occlusive disease of lower leg and pedal arteries in hypertensive patients undergoing infrainguinal bypass procedures.

OBJECTIVE: To analyse the atherosclerotic involvement of lower leg and foot arteries in patients undergoing infrainguinal bypass grafting. SETTING: Department of Surgery, University Hospital. PATIENTS: Among 282 limbs (267 patients), fifty limbs belonged to hypertensive nondiabetics (Group A), 39 to hypertensive diabetics (Group B), 129 to normotensive nondiabetics (Group C) and 64 to normotensive diabetics (Group D). INTERVENTIONS: Femoropopliteal or femorodistal bypass procedures. MEASURES: Intraoperative postreconstruction serial angiography of the lower leg and foot arteries. RESULTS: Occlusion rate of two or three lower leg arteries was significantly higher among diabetics (Group B 77% and Group D 73%, respectively) compared to nondiabetics (Group A 56% and Group D 51%, respectively). It was similar in diabetic patients with or without hypertension. The incidence of having both foot arches (dorsal and plantar arch) intact was significantly higher in nondiabetic patients with hypertension (Group A). Only 5.8% of these patients demonstrated both deficient or occluded foot arches compared to 18% in Group B and 31% in Group C and 20% in Group D. CONCLUSION: Hypertension does not seem to contribute to the extent and severity of lower leg and foot vessel involvement in patients undergoing infrainguinal bypass surgery.

Aged↗
PubMed1996

Spontaneous internal carotid artery dissection. Review.

Spontaneous ICA dissection is an increasingly recognized cause of stroke especially in young adults. The most frequently reported site of involvement is the cervical part of the internal carotid artery (ICA). Although several primary arteriopathies have been related to the development of spontaneous ICA dissection the cause is not clear in most cases. The clinical picture varies from mild cerebral and/or cranial nerve dysfunction to a completed stroke. Angiography has been considered as gold standard in establishing diagnosis. Recently, duplex scanning has emerged as a powerful noninvasive diagnostic tool only in the initial assessment but in the serial follow-up of patients. Early diagnosis is essential as these lesions require anticoagulant treatment. Immediate heparinization is instituted after diagnosis, followed by oral anti-coagulation for at least six months. Surgical treatment is warranted in only few cases. Complete resolutions of the dissection is seen in at least 50% of cases. The risk of recurrent stroke remains low in patients discharged alive after spontaneous ICA dissection.

Adult↗
PubMed1995

The effect of postocclusion reactive hyperaemia, papaverine and nifedipine on duplex derived haemodynamic parameters of infrainguinal bypass grafts.

OBJECTIVES: The aim of the present study was to analyse the effects of various vasodilating stimuli on postoperative infrainguinal graft haemodynamics. DESIGN: Duplex derived haemodynamic parameters of infrainguinal bypass grafts were measured at rest and after postocclusion reactive hyperaemia, intraarterial papaverine (40 mgm) injection and peroral nifedipine (10 mg) administration. SETTING: Department of Surgery, University Hospital. MATERIALS: Twenty-nine patients with infrainguinal bypass grafts were studied by Duplex scanner after a median of 25 months postoperatively. CHIEF OUTCOME MEASURES: Peak systolic velocity (PSV), mean velocity (MV) and volume flow (VF) were measured at rest and after various stimuli. MAIN RESULTS: VF at rest increased from 125 +/- 16 ml/min (mean +/- S.E.M.) to 271 +/- 26 ml/min after papaverine administration and to 205 +/- 19 ml/min during reactive hyperaemia (p < 0.001). PSV, MV and VF increased significantly during postocclusion reactive hyperaemia and papaverine injection. After nifedipine administration VF increased to 154 +/- 21 ml/min after 30 min (p < 0.001) and there was a significant increase in MV (p < 0.05). CONCLUSIONS: Duplex derived flow measurement of infrainguinal bypass grafts can evaluate graft and limb haemodynamics in the postoperative period. Pharmacological manipulations, such as vasodilation, can influence the physiological runoff with subsequent increase in volume flow through the graft.

Aged↗
PubMed1995

Comparative analysis of patency, limb salvage and survival in diabetic and non-diabetic patients undergoing infrainguinal bypass surgery.

In 92 diabetic and 175 non-diabetic patients undergoing 336 femoropopliteal or femorodistal bypass procedures, 1- and 3-year cumulative life-table patency, limb salvage, and survival rates were comparatively analysed. The peroperative mortality rate was significantly higher in diabetic patients (5% compared to 1.4%, p < 0.001). The cumulative graft patency rates were 61% at 12 months and 46% at 36 months in diabetic patients compared to 64 and 52% in non-diabetic patients. Significantly better patency rates were observed in limbs with good runoff compared to limbs with poor runoff in both groups. The limb salvage rates at 3 years were 70% in diabetic patients and 62% in non-diabetic patients. The survival rate at 3 years was significantly lower in diabetic patients, 62% compared to 86% in non-diabetic patients. Diabetic patients with poor runoff demonstrated a significantly lower survival rate after 36 months compared to diabetic patients with good runoff (48% and 74%, respectively). The results of this study demonstrate that the early and intermediate patency and limb salvage rates are similar in diabetic and non-diabetic patients. On the other hand the survival rate in diabetic patients, especially in those with poor distal runoff, is significantly lower than non-diabetic patients.

Aged↗
PubMed1995

Long-term follow-up of autologous vein grafts. 40 years after reconstruction for cystic adventitial disease.

Long term follow-up (38-41 years postoperatively) has been undertaken in three patients who were initially operated on with autologous reversed vein grafts due to cystic adventitial disease of the popliteal artery. The patients were evaluated clinically as well as with colour coded ultrasonography and phase-locked echo-tracking ultrasonography. One vein graft was occluded, the others were patent, without dilatation and with a compliance similar to that in the femoral artery. Autologous vein grafts below the groin are very durable.

Adult↗
PubMed1994

Duplex ultrasound scanning for diagnosis of aortoiliac and femoropopliteal arterial disease.

Forty patients with symptomatic aortoiliac and/or femoropopliteal occlusive arterial disease subjected to angiography were studied with duplex ultrasonography. The duplex scanning of the aortic, iliac, femoral and popliteal segments had a sensitivity of 93% in detecting significant stenoses and a specificity of 91%. The positive and negative predictive values were 75% and 98%, respectively. The sensitivity was relatively low in low-flow segments distal to total occlusions especially in patients with severe iliac disease and multiple distal femoropopliteal lesions. The results demonstrate the reliability of duplex scanning in detecting aortoiliac and femoropopliteal lesions.

Aorta, Abdominal↗
PubMed1992

A new biodegradable patch for closure of atrial septal defect. An experimental study.

Biodegradable patches made from polyhydroxybutyrate (PHB) were used to close experimentally induced atrial septal defect in six calves. The implants were evaluated after 3-12 months macroscopically and by light and scanning electron microscopy with regard to regeneration of tissue and degradation of the polymer. At implant degradation, complete endothelial layers facing the right and left atrium were observed, with a subendothelial layer of collagen and some smooth-muscle cells. The patch was degraded by polynucleated macrophages, and 12 months postoperatively no polymer material was identifiable at ordinary light microscopy, but in polarized light small particles of polymer with persisting foreign body reaction were still seen. Scanning electron microscopy revealed a complete layer of surface cells with morphologic signs of endothelium. There was no shunt or sign of infection. Biodegradable PHB patches implanted in atrial septal defects in this experimental model thus prompted formation of regenerated tissue that macroscopically and microscopically resembled native atrial septal wall. The total degradation time exceeded 12 months.

Animals↗