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Biomedical subjects

H Loeprecht

Publications and source records attributed to H Loeprecht.

At least 19 recordsLinked to original sources
PubMed1992

Technique and results of vascular endoscopy in arterial and venous reconstructions.

In an effort to maximize results, vascular endoscopy was used in our institution to monitor arterial and venous reconstructions. Since 1982, angioscopy was applied as a control method in 182 venous thrombectomies to treat iliofemoral thrombosis and 114 aortoiliac thromboendarterectomies. Of the cases with venous thrombectomy reviewed, 50% were incomplete by endoscopic evidence; of these, in 80% the remaining clots could be partly or completely removed. Additionally, in six patients a venous spur was found. Of 114 attempted aortoiliac thromboendarterectomies, only 91 could be completed. In the remainder, endoscopic evidence of persistent intimal flaps forced us to bypass the affected segments. With further miniaturization of the angioscopes, the method was also applied to check vessel repair on small-caliber arteries. In an initial study with 220 femorodistal bypasses we were unable to find a statistically significant difference of primary patency in grafts that were endoscopically controlled or not. In the learning phase with the in situ technique, we identified competent valve remnants in 40%, but this rate could be reduced to 12.7% with growing experience in valvulotomy. We conclude from our data that angioscopy is very helpful in assessing the morphological integrity of aortoiliac thromboendarterectomies and venous thrombectomies. The actual value in infrainguinal arterial reconstructions still remains to be proven.

Angioscopy↗
PubMed1992

[Duplex sonographic monitoring of infra-inguinal arterial reconstructions: can a threatened bypass occlusion be detected by this method?].

In our institution, 95 infrainguinal arterial reconstructions were prospectively entered into a graft surveillance programme which consisted of a postoperative i.a. DSA and routine assessment of graft flow velocity (GFV) and ankle pressure indices (ABI) during the first postoperative year. An average of 4.1 GFV measurements was obtained during a mean follow-up period of 8.2 months. Abnormal GFV led to arteriography in 29 bypasses identifying--aside from three false positive findings--two graft occlusions and 24 severe (> 70%) graft stenoses. Of the latter, in only 7 cases a significant decrease in ABI was found. Unheralded graft occlusion occurred in 6 patients. Including the corrections of the above mentioned lesions, secondary patency rates were 97% at 30 days and 89% at one year.

Aged↗
PubMed1992

[Determination of vascular resistance in bypass operations with infragenual anastomosis: is prediction of early occlusion possible with this value?].

Peripheral outflow resistance (OR) was assessed intraoperatively in 75 infrainguinal bypass procedures to the below knee popliteal artery (20) or a single crural artery (55). OR measurement was done after completion of the distal anastomosis. For that purpose, the graft was perfused with Ringer solution at constant flow rates of 100 and 150 ml/min using a roller pump. During infusion, arterial pressure was recorded. In this way distal (DOR) and total (TOR) outflow resistance in E/S anastomoses was calculated before and after vasodilatation with papaverine. DOR at a flow rate of 100 ml/min was found to be most discriminant as a predictor of early graft thrombosis: 1. In the limbs with a thrombosed graft at 30 days OR was significantly higher than in the limbs with a patent graft (1828 +/- 418 vs. 1472 +/- 221 mPRU; p less than 0.01, Mann-Whitney U-Test). 2. The cut-off value of 1700 mPRU, which was determined by ROC curves, was 100% sensitive and 81% specific in the group of femoro-crural grafts to predict early graft failure. A better discrimination by the application of papaverine could not be achieved. We concluded from our results that OR might be an important factor in early graft thrombosis. But still there is more experience required to select patients for primary amputation or adjunctive procedures (av-fistula, sequential graft) on the basis of the present available data.

Arterial Occlusive Diseases↗
PubMed1990

Significance of transcranial Doppler CO2. Reactivity measurements for the diagnosis of hemodynamically relevant carotid obstructions.

Transcranial Doppler ultrasonography can be used to determine CO2 reactivity in the large basal cerebral arteries. CO2 reactivity is expressed as percentage increase of mean flow velocity above one volume percent of CO2, using a reference value of 40 mmHg pCO2 normalized autoregulatory reserve. A normalized autoregulatory value of 15 as the lower limit of the normal range clearly separates patients with internal carotid artery obstructions greater than or equal to 70% from the control group. Stenoses of the ipsilateral internal carotid artery of greater than or equal to 70% result in a significant decrease of normalized autoregulatory reserve in the middle cerebral artery, which can be normalized by removal of the upstream flow obstacle using a carotid thromboendarterectomy. The scatter of normalized autoregulatory values in severe internal carotid obstructions indicates the variability of collateral circulation A retrospective comparison of normalized autoregulatory reserve and ipsilateral ischemic symptoms in the supply area of the internal carotid artery reveals a significant correlation between clinical symptoms and reduced normalized autoregulatory reserve.

Adult↗
PubMed1989

[Cost-benefit analysis of saving the leg].

To acquire cost-benefit analysis data for limb salvage a prospective study was performed between 1. January 1988 und 30. Juni 1988, including 128 admissions for AOD Stage IV or acute complete ischemia. After dividing the patients into three groups--limb salvage (LS), limb loss (LL) and primary amputation (PA)--the average total costs per admission were calculated. In the LS group these costs amounted to DM 14,652 for all cases and DM 14,069 for the survivors, in the LS group to DM 25,364 and DM 27,583 and in the PA group to DM 22,946 and DM 28,186. Therefore in light of the total costs alone every effort should be made to salvage threatened limbs.

Aged↗
PubMed1988

Intraoperative assessment of in situ saphenous vein bypass grafts by vascular endoscopy.

Intraoperative vascular endoscopy was used in 20 femorocrural in situ saphenous vein bypass procedures in order to control valvular incompetence, to localize side branches and to assess the integrity of the distal anastomosis. We used an Olympus Fiberscope (PF-27L) with a diameter of 2.7 mm and a working length of 80 cm, which had fixed illuminating and viewing fibers and a steerable tip, Valvulotomy was performed according to the technique described by R. Leather using a valve-cutter. In 8 out of 20 patients, partly retained valve leaflets were found by intraluminal inspection and could be immediately corrected. The integrity of the distal anastomosis was verified angioscopically in 14 patients. In addition, venous side branches, which had to be ligated, were easily identified under direct vision and localized by transillumination of the endoscopic light through the skin. Vascular endoscopy seems to be a practicable and time saving method to control in situ vein bypass procedures. The steps of the procedure and early results after 20 bypasses for limb salvage are presented.

Anastomosis, Surgical↗
PubMed1988

Chest wall resection---alloplastic replacement.

In a retrospective study of 302 patients, who were operated on in our centre between 12/85 and 9/87, 25 patients required a chest wall resection. The most frequent indication (11 times) was an infiltration of the thoracic wall by bronchial carcinoma. 8 times we resected a primary rib tumour, in rarer cases a thoracic wall resection was required for mesothelioma, echinococcus alveolaris and tuberculoma. In 10 patients the defect was too small to require a patch. Initially we applied Marlex-mesh and Vicryl-mesh to cover the defects. In our last 10 cases GORE-TEX-2 mm-patch was used. The technical ease of the method, the mechanical stability and durability, the tightness for air and fluid and the positive tissue response speaks for the continued application of this material. Additional methods such as myocutaneous flaps are not necessary and should only be used in complex defects.

Adolescent↗
PubMed1988

[Venous thrombectomy: indications, technic and results].

Venous thrombectomy is a promising approach to treating acute iliofemoral thrombosis with comparable results to those of thrombolysis. It is the treatment of choice in cases of thrombosis caused by pregnancy, delivery, surgery (early postoperative period) and trauma. The success depends on the age of the thrombus, skilled surgical techniques with atraumatic preparation and intra-operative endoscopic control. Creation of an adjunctive av-fistula is mandatory to protect against reocclusion. Followup includes X-ray and checkups. Reininterventions are possible.

Humans↗
PubMed1987

Advances in vascular endoscopy.

In reconstructive vascular surgery several intraoperative investigations are in use to check-up and secure full blood flow restoration (angiography, ultra-sound, electro-magnetic flowmeter etc.). In the last years endoscopical lumen control, introduced 1969 in clinical praxis, could be remarkably simplified and improved. For vascular endoscopy three technical prerequisites are necessary: a) temporary interruption of blood flow using clamps or balloon catheters, b) replacement of the blood by a transparent medium via pressure controlled saline perfusion, c) availability of suitable special endoscopes. The main application of vascular endoscopy includes: a) semi-closed thromboendarterectomy (aorto-iliac or femoropopliteal), b) arterial embolectomy, c) lumen control of inserted grafts including the anastomosis and the distal run-off vessels, d) venous thrombectomy. The availability of small-calibre endoscopes (external diameter: 1.7-2.7 mm) enables the extension of lumen control to small vessel areas such as the tibial and coronary arteries. Compared with angiography vascular endoscopy offers several convincing advantages such as a more reliable three dimensional lumen control, easy performance, saving time and the avoidance of any additional X-ray exposure. Technical faults or overlooked concomitant vascular lesions can be diagnosed and corrected immediately.

Angiography↗
PubMed1985

[Can EEG monitoring with the Trend Analyzer replace stump pressure measurement in carotid surgery?].

Description of the EEG-trend-analyzer as an intraoperative monitoring during carotis surgery. Criteria for the evaluation of the findings are presented. In a prospective study 92 patients underwent monitoring with the EEG-trend-analyzer as well as the measuring of the internal carotid artery stump pressure. EEG monitoring shows a sensitivity of 100% for ischemic events, compared to 67% for the stump pressure measurement with a threshold of 50 mm Hg. EEG monitoring shows false positive results in 25% but no false negative results. Stump pressure investigation of the internal carotid artery is a very unreliable parameter for cerebral ischemia and inferior to the results of EEG-monitoring.

Blood Pressure↗
PubMed1979

[Gastroesophageal reflux: a factor eliciting esophageal variceal hemorrhage?].

Following a hemorrhage, ten patients with esophageal varices were examined by means of gastroscopy and functional analysis of the esophagus with special regard to gastroesophageal reflux. A pathological gastroesophageal reflux was not confirmed. These results plus previously published findings lead to the assumption that reflux is of not importance in the initiation of esophageal variceal bleeding.

Adolescent↗
PubMed1978

[Reconstructive surgery on the venous system].

1. The progress of reconstructive venous surgery in recent years has been mainly based on the use of changed operative techniques (atraumatic preparation and suture technique; intraoperative vascular endoscopy or venography; temporary arteriovenous fistula). As a result, the clinical indications could be remarkably increased (acute phlebothrombosis; some types of post-thrombotic syndrome; venous substitution in tumor surgery; vascular lesions). 2. A peripheral temporary arteriovenous-fistula proves the most effective protective method both in venous thrombectomy and in graft reconstruction (full lumen restoration also in cases with incomplete disobliteration due to increase of flow velocity and flow volume; improvement of graft patency). 3. In long-standing axillar or subclavian venous thrombosis, a distal arteriovenous fistula (similar to a Cimino shunt) has a curative effect (without venous thrombectomy) via stimulation of rapid recanalisation and formation of collateral pathways. 4. Persisting central venous blocks may be corrected by a bypass procedure (great saphenous vein graft for the shoulder region; expanded PTFE grafts (Gore-Tex) for the ilio-caval segment).

Adult↗